This is the Aiyima T8 Review. I’ve said before that I’m no expert on audio stuff. I give my honest opinion on it and list my commentary on what I thought about different products. Aiyima might not be all that new but it’s pretty new to me. I have the Aiyima T8 DAC/Headphone Amp/Pre-Amp to take a gander at. I’ll break it down into several parts to make it easier to navigate.
First Impression
The First impression on the Aiyima T8 is….it looks weird. The bright red volume knob reminds me of Bozo’s nose. The wood rails at the top to keep fingers off the vacuum tube seem oddly out of place. The rest of it seems really well made. Recessed machine screws hold everything together. The brushed aluminum frame is matte black and looks great. The “OLED” display is crisp and not overly bright. All the inputs and outputs are clearly labeled to avoid confusion.
Aiyima T8 FrontAiyima T8 Tube insert
Assembly
Assembling the Aiyima T8 pro is easy. You have to insert a vacuum tube which only goes in one way, screw in the antenna, and plug in the power cord. Done.
Aiyima T8 Accessories
Operation
The volume/power knob (Bozo’s nose) has a quality feel to it. Firm detents and clean clicks with no wobbles or mush. The display clearly shows you what is going on detailing the input, volume, as well as the sampling rate of the input signal. You also get a remote control which I’ve barely used. It adds a great value if used as a pre-amp that will be out of arm’s reach. I’m using the T8 on my desk so the remote is not really needed for my current use.
Options
On the Aiyima T8 you have the option of Coaxial input, RCA input (and RCA output!), Optical, and Bluetooth. That’s a lot of inputs for a $129 audio gadget. Switching inputs is a click of the volume knob or remote button away. As for tube options, you can go with the GE5657, 396A, 2C51, 12B4A, or the 6H3N. The people at TubeDepot in Memphis are very helpful if you have questions about tubes/valves. They also have some DIY amp kits for the ambitious (and opulent).
Inputs and outputs of Aiyima T8 Tube
Thoughts
This thing is QUIET! No hum, buzz, chirping, clicking………… nothing! Pretty impressive at this cost level. As a DAC it was instantly recognized by my PC and worked flawlessly. Bluetooth was equally quiet which was a surprise to me as well. With all the wireless stuff and power adapters on my desk I figured there would be something unwelcome in the signal. Nope. I tried several different headphones with this and they were all very clear. I will say that I had to use some equalization to get it where I liked it but I think my ears are spoiled.
CONS
The red knob and wood rails bother me for some reason. They just seem oddly out of place. That’s pretty much it for the cons.
PROS
It’s QUIET!
The Aiyima T8 operates flawlessly.
Lots of inputs.
Remote control included.
The vacuum tube is located right on top so tube rolling will be quite easy.
The SMSL HO100 being reviewed is a budget friendly, no frills headphone amplifier. It is absolutely about one thing quality. And when I say no frills, I mean it. It is a classic all aluminum frame with a beautiful glass bezel but it only has your basic controls on the front panel. those include three toggle switches to switch you amplifier on off, switch between xlr and RCA inputs as well as a high mid and low gain selector. You will also have your headphone outputs (a 4.4mm for balanced output and a ¼” for unbalanced out) which should have you covered for most types of headphones that you will be using. And finally it has a volume knob on the right hand side. when you turn it around you aren’t going to see much. In fact, all you will see is the XLR balance inputs, and your unbalanced RCA along with an IEC jack for power. And they have all of this in a small compact case. In fact, the case is only 5 inches long by 6 inches wide and 1.5 inches tall and it only only weighs 1.23 pounds.
Build Quality
Now, although I see this is no-frills, remember I said that the SMSL HO100 is all about quality. And you start to see the attention and care they put into this amplifier as soon as you start to use it. In fact, it was very clear they didn’t cheap out on materials like many companies are doing now a days. From the first time I picked it up, you could tell this unit was solid. The all aluminum exterior was robust for its size and weight. In fact, the overall build quality is exactly what I would expect from SMSL’s higher end line, not this one. In fact it is the same fit and finish as their much more expensive HO200.
The HO100 toggle switches are nice and rigid with that think that you like to hear from good quality toggles. They have all gold finishes on the inputs and outputs and even the volume control is very smooth without any type of hesitation. Honestly, the switches and knobs feel exactly like they do on their higher end units. They did not cheap out on these and that is very nice to see. I was also surprised to see that the HO100 included a built in power supply, so no bulky power supply hanging out your desk just a simple power cord that you can plug into the wall. This makes for a much cleaner install. And thankfully, with the power supply built-in you do not have to wonder if you are going to get a noisy power adapter. Making this more likely to sound just like SMSL intended.
Power
The HO100 also packs quite a bit of punch for its size. It can deliver three watts of power into 16 ohm headphones or one and a half wants into 32 ohm headphones. Which is going to be about half the wattage that you would see on a higher end headphone amplifier like the HO200. However, in this type of price range I think this is exactly what you should expect. And honestly in this price range you’re most likely going to be using some of the lower impedance headphones. And it is those Headphones that this type of headphone amplifier is specifically tailored for. And during my testing I didn’t have any issues driving my headphones to more than adequate levels.
Sound Quality
It is important to note, that although it does have the fit and finish and the look of a high-end headphone amplifier, the most important thing of any headphone amplifier is its sound quality. And although I know, SMSL makes some high-quality gear I was not expecting the sound quality that I got out of the HO100. Not only did this headphone amplifier exceed my expectations on sound quality. It sounded just as good as it’s a bigger brother, the HO200 it was crisp and clear and very neutral. It didn’t add any bass or treble like some of the cheaper headphone amplifiers do. Best of all, the HO100 was absolutely silent. When I say silent, the unit itself is obviously silent as it is all solid state with no fans. So the operation of the unit itself is silent. But what I say silent I’m talking about the distortion and noise floor. The total harmonic distortion plus noise is -123 dB. That is well below human hearing! But if you want to visualize that as a percentage, it is 0.00006%. That is astronomically low! And a lot lower than I would ever expect in a headphone amplifier at this price range. And this absolutely made a huge impact when listening to music during those silent scenes. Instead of hearing a hiss or a noise that wasn’t there, I heard nothing. Silence. And that’s exactly what I want from a headphone amplifier. And I definitely as not expecting it in this price range.
Measurements of the HO100
It is one thing for me to tell you this, but it would be nice to back it up with some measurements. Unfortunately, I don’t have the access to be able to measure this myself, but one thing that SMSL does is they provide all the measurements for you. When we take a look at their measurements, we see that the frequency responses from 20 hertz all the way up to 100 kilohertz and that frequency response is completely linear and that explains why this amplifier is so great at reproducing exactly what the artist had intended.
Shortcomings
Now it’s rather obvious that I love the sound quality and the fit and finish of the HO100. But that doesn’t mean that I love everything. There are some cons to this headphone amplifier. For example, when we look at the HO200 it’s bigger brother you’ll notice that you’re actually getting some balanced and unbalanced outputs. This allows you to hook up something like powered desktop speakers, to the back of this. Allowing you to simply toggle between your headphones, and your speakers with the flip of a switch. The less expensive alternative doesn’t have any type of outputs like that so this truly is only a headphone amplifier. And that’s not really a problem as long as you understand what you’re getting.
Final Thoughts on the SMSL HO100
Now this is probably a first for me because I don’t really have anything negative to say about this amplifier. Honestly, it blew away all of my expectations and it has become my favorite budget headphone amplifier. In fact, if you’re looking for a headphone amplifier in the $150 range I wouldn’t look any further. I just don’t see you being able to get anything better than this in that price range, but having said that if you do need some more outputs, then look at some of my other reviews where I looked at the topping and of course the SMSL HO200. Now It is time to figure out exactly where to place this on my list? I am going to place it right below the SMSLHO200. Mainly due to the fact it doesn’t have any RCA or XLR outputs and is lower wattage. However, ti has the advantage with it’s size. And if you don’t need the wattage or outputs, then I would absolutely buy the HO100 over the HO200.
Is a budget DAC worth it in 2022? Well, that’s the question we’re going to try to answer by looking at the SMSL DO100, which retails right around $230.
SMSL sent the DO100 for me to review. And I was very interested in it, because I already have a DO200, which I really love and enjoy, but is about twice the price. The DO100 is its smaller brother in both size, features and of course price. If we take a look at the back, it does have all the digital inputs that you would want, such as USB, digital fiber optic, digital coaxial and even Bluetooth 5.0. It also has your unbalanced RCA and balanced XLR outputs so that way you can go into something like another amplifier, or even a headphone amplifier, depending on how you want to utilize this particular dac.
Before we review the sound quality of the SMSL DO100, I want to first talk about its overall quality. And I got to say that SMSL D100 has hit it out of the park. I absolutely love the different varying brightness levels of this particular dac and all the different menus that you can go in and change as nice to have.. It’s all aluminum frame is very robust for its size. And honestly, is on par with something like the HO 100, or even the bigger brother DO200, as far as build quality goes. They do give you a remote control which is their standard remote that is used on most of their units.
Display
Since the SMSL DO100 is a budget DAC that is being reviewed. There are going to be some things that you are going to notice that are lacking on this particular model. For example, the screen is nice and bright, and I do enjoy that. However, it is using older technology that ahs a limited range in reproducing letters. Although, this isn’t an issue, it does make it look cheaper and is a little harder to navigate the menus. For example, when we go through the menu system, you can’t easily identify what you are changing. Thankfully, the manual clears that up for you. Another disappointment, is the DO100 is missing one of my favorite features of the SMSL DO200, sound color modes. This is a built-in feature that changes the way the DAC sounds. You can even make it sound like a tube amplifier if you want. WIth the DO100, you can’t do that without another device.
Technical Specs
What was surprising for this price range is that the SMSL DO100 does do DSD512, PCM 32/768 as well as your Bluetooth support for (LDAC, APTX/HD, SBC, AAC). And that’s something I just didn’t expect any price range. And all of these help give you the best sound quality you could expect from a DAC. Speaking of sound quality, that is most important thing with any dac. And I gotta say, once again, SMSL has hit this out of the park.
Not only do we take a look at the graphs SMSL provided of the DO100 and we see very low distortion, but it also does a great job at reproducing exactly what it is that the artist intended. It doesn’t add any coloration to it and the sound came across crystal clear, crystal clean. And I got to be honest, I really enjoyed the sound. Now, my particular headphones, the bare dynamics, DT770 pros, do get a little bright during certain songs. So I would have appreciated a way to attenuate the treble or the addition of sound color modes.
Final Thoughts on the SMSL DO100
As of now, if you did want those, you would have to buy a more expensive dac, like the DO200. And if I am to be frank, in this particular price range, for a dac of this size, I don’t know that there’s much more that I could personally ask for. It is a really good value. Now, having said that, I’m going to go ahead and show you where I put it on my list. And I put this right around here. I would still take the SMSL DO200 over it, even though it is a lot more expensive. In this case, I think the expense is warranted. You get the better screen the more extensive menu system and the sound color modes. All of these, adds quite a bit of value. However, if those things don’t interest you, I think the SMSL DO100 is a great value.
You may wonder what tools are needed to get started building your own custom loudspeakers. The list is surprisingly small if a person is simply trying to build a basic box with bracing. What tools do you need? A plunge router with bits, a circle jig, and clamps. Is that really it? Yes, surprisingly. But don’t you need your sheet goods broken down? Yes. You can often be deal with that if you are willing to pay. We’ll discuss the alternative to paying, which includes a router and a straight edge, you’ll just have a bit more kerf. All in due time.
The Plunge Router
This is one of the most versatile tools of woodworking. You can use a router to cut holes, to flush trim the edges, to rabbet the wood, to cut dadoes and grooves, to create interlocking edges, and even to surface a face of a project (not needed for speaker cabinets, but still cool).
Uses of the Router
A router is one of the easiest ways to cut circles into a baffle. This includes recessing the frame of the driver to sit flat with the surface of the baffle. The primary ways in which a beginner cabinet maker will use this tool is basic rabbeting, plunge routing, flush trimming, and round-overs or chamfers.
Rabbeting Bits
When will you need to do each of the above? For rabbeting, you use this if you want the edges of the enclosure to have a stepped edge to increase glue surface contact area. The other way you could use rabbeting is to create the recess for drivers or to fix if you did not reach the right depth when doing this the other way discussed below.
Plunge Routing
As to plunge routing, you will use this when cutting out the driver holes in the baffle. It can also be used when cutting out the area for a terminal cup. Or you can also use this to cut out the holes in bracing or to create dadoes and grooves. Then you can either take a straight edge of a piece of wood, clamped down or with double sided tape, but I prefer clamps, or a straight edge clamp or a track for a track saw if you have a track guide for your router model, and you can run it at the specific depth you need to get a clean dado or groove.
Flush Trimming Bits
For flush trimming, you will be using the bit to fix any protrusions where the walls of the cabinet meet so that you get a seamless surface for each side. Simply put in the flush trim bit and run it over the edges that are protruding with the bearing riding along the lower surface. This knocks it back down level with the side while saving a little time and effort on sanding.
Pro tip: if you did not get a great seal when gluing or you see a partial gap, take some of the sawdust from all the routing, mix it with some wood glue, then apply this to the area. You can do this with a putty knife, if one is available. But if in a pinch, you could even force it into the crack with some cardboard or a political mailer, after all, those are trash and just going to be thrown away anyways. You might as well get more use out of it than the politician did.
Round-overs and Chamfer Bits
Finally, you have round-overs and chamfers. This is primarily for the fit and finish of the final product. It’s often nice to use the router to take the sharp edge off the wood, especially if you have small children prone to falling over at home. Not only this, but chamfers often have some of the best effects on diffraction. That is unless doing large round-over radii or building a round speaker like a globe. But considering this is written for those just starting, it is foolish to talk about a globe style speaker.
Recommendation
For my recommendation on the type of router to get, if you can only get one (two is always better), is to get a nice 2.25 HP plunge router. A trim router would be the next one I would recommend. Lastly would be a beastly 3.25 HP router for use in a router table. But, when just getting started, the 2.25 HP is the right blend of versatility and size, with the ability to handle both quarter and half inch shanks for your bits. Now, if you can buy a second one, a trim router will make the round-overs and chamfers much easier. They are small, comparatively, and able to quickly and easily control when running around to take off the sharp edges.
Dewalt DW618PK
The Router Bits
We covered a plethora of tasks that can be done with a router. But you still have to have the right bits for the job. Now, bits are consumable. If you are unsure what bits you need, I’d recommend getting a C3 carbide general set with half inch shanks from Yonico or Kowood. These bits are great for the price and these brands use C3 carbide rather than a different level of carbide. C2 is a bit soft, whereas C4 is harder, but can crack and shatter easier on nails and similar objects. On the other hand, if you have the money and know you will be using that bit a fair amount, it might be worth the money to splurge on the higher end bit.
It is important to remember that bits will wear down, chip, and possibly even break over time. Do not wait to replace your bits until this happens. A bit breaking while spinning at thousands of rotations per minute in a router is extremely dangerous. If you see the bit is chipped and possibly cracked, please, for your own safety, replace it. As such, don’t think these will last forever. But, the more expensive bits will last for a longer period of time. Do a cost benefit analysis on time and usage to decide if you, personally, would benefit from replacing with a cheaper bit or a high-end bit.
Get the Rabbet
With that said, you will likely want to get a rabbeting bit set. These come with swap-able bearings. I prefer buying a more expensive bit set with a coating to help the bit last longer. These sets usually also have extra bearings that give more options on rabbeting depths as well. I have enjoyed my Freud set. But there are many fine brands, from Whiteside with Astra Coating sold by Bits & Bits to CMT. For this, I do recommend spending the bit extra for a good set, that way it will last you longer.
Sometimes, circle jigs require a specific size bit, such as the Jasper Jig, discussed below. When that is the case, I prefer to buy a dedicated bit that I store with the Jig. In my case, I purchased a Whiteside RU4700 standard spiral up cut bit made of solid carbide. Bits & Bits does not carry this SKU with an Astra coated finish, but it is found on Amazon, has an half-inch shank, a quarter-inch cutting diameter, and an one-inch cutting length. If taken care of, this bit will be very robust and will last quite some time alongside the jig.
With that said, if trying to buy bits for the router on a limited budget, you might try to find a cheaper set of bits, like mentioned above, that has a quarter inch diameter, half inch shank with it, just to save on initial purchase cost. You can always buy the better bit later after you have consumed the initial one in a kit. But the spiral bit is better than the straight edge bits often found in these kits.
Buy Router Bits In Bulk
The other bits needed, such as round-over, chamfer, flush trim, and dado/straight edge bits can generally be bought in a set like those mentioned above. When you wear them out, you may consider purchasing a higher end replacement. But until then, you are getting started and this is more than satisfactory to get going on building your own cabinets, get used to maintaining the bits, and to get them all in an affordable package with other bits for other projects. Generally, buying a good version of each bit you would use will cost as much or more than buying the kit while also not getting other versions of bits in different sizes that you could find useful in certain cases. As such, I recommend a bit set to start.
Give ‘em the clamps, Clamps!
Clamps are the bane of most woodworkers. Why? Because you can never have enough and there are so many different versions you need to do different tasks. When starting out, I personally recommend getting some cheap versions of the following types of clamps.
Strap/Band Clamps
Strap/band clamps are great for making boxes. These are made so you can vary the strap length, use the 90 degree portions that the band slips through (which can be removed in the event of having large round-overs where the corner cannot sit properly in the 90 degree part) to help grab the edges, then pull tight and twist the handle of the clamp to tighten into place. These are an excellent value for what they do.
Pipe Clamps
These are more expensive, but have a lot of versatility. You can use these with any length of pipe, which helps greatly. But, it also requires you to buy the pipe, which can get very expensive. The pipe multiplies the cost greatly, so although it can be used with many lengths and in many ways, it is not the most economical clamp, necessarily, for starting out woodworking. It is cheaper than cabinet clamps, though, and able to have an internal clamping length longer than many for the price. This is especially true if building tower speakers.
Bar Clamps
These simple clamps are much like the pipe clamps, except you cannot swap out the length of pipes. This means you will need to have many clamps of the same length and the storage space to put them when not in use. If you bought four pipe clamps, you could just swap out the length of pipe. But bar clamps are fixed. The up side is these are finished products and you can grab and go.
They also come in many styles, including having quick release mechanisms, F-style, and parallel (which has parallel surfaces and is excellent for cabinet making, but comes at a much higher cost). For starting, I’d recommend, if on a budget, picking up some F-style bar clamps or some other style of bar clamp and getting more at a later date. After all, you may need to clamp down the pieces to your work surface to route or need longer ones to clamp the box together during a glue up if not using the band clamps (or using both).
Didn’t You Say The Sheet Needs Broken Down?
Of course you have to break down the sheet into the smaller pieces in order to make it usable.
Have Someone Else Do It
What many may not realize is that if you are nice to the people at your big box store or many other stores where you can buy sheet goods, they can usually cut the sheet down a bit for you. Some stores have a policy of one or a few cuts. That would allow you to turn the 8’x4’ into two 4’x4’ to bring home. Beyond those initial free cuts (or cuts you sweet talk your way into for free), many stores will continue cutting to break down the sheet for you for a nominal fee.
Because of this, if you come prepared, you can have them cut the pieces slightly oversized and pay for it there, that way you do not need a table saw or a track or circular saw. After that, if you use a straight edge guide with the plunge router, you can clean it up to the final size with a nice edge.
Plunge (Router) Away
In the alternative, you can take a straight edge bit that can go through the entire thickness of the sheet, layout your cuts, and then use your plunge router to cut down the sheet. Granted, this will lose a fair amount to kerf, the waste due to the thickness of the bit used, but it will give a straight edge so long as the guide edge you use is straight. Just use a combination square to have a proper line to reference that is parallel to the factory edge.
Also, you will have to know the offset from the bit to the clamped straight edge you are using to push your plunge router against while routing. Just use a scrap piece of wood to figure out this offset and things become much simpler. You place a second line that offset distance from your cut, then you clamp the straight edge to that line and guide the router. Very simple.
A Perfect Circle Is Not Just A Band, It’s a Jig
You may wonder how do I get the circles cut into the baffle for my drivers? That is simple enough and there are numerous ways to accomplish this.
DIY Jig
The cheapest is to drill two holes in a piece of wood. One is for the pivot point, which you want to drill it large enough to use a nail or similar in the center of the circle. The other hole must be large enough that the bit can fit through. You measure and set the distance between the two holes to the radius of the circle you are trying to create. Then you attach that piece of wood to your router as a base. The benefit is this is cheap. The drawback is that it fits only that size circle (unless you recreate a Rockler style circle jig).
Store Bought Jig
The next way to accomplish this is to buy a jig. I like the ability to dial in the size seen with Jasper jigs. They lay out the pivot points in a grid style that makes it incredibly easy to make the perfect circle every time. Another is the Rockler style. For this, they have it where you can slide the pivot point closer to get the right radius. This allows for setting the distance between the bit and pivot at more intervals. But it also takes more effort to make sure you have to radius set correctly. Both are great, but I personally went with the polycarbonate Jasper Jig.
As to making the circles, you also have a choice to either make the recess now with the jig for the driver to sit flat or to use the rabbeting bit. You would set the plunge depth to the level to make the driver frame sit flush. But you will have to route out in stages to that depth at various distances from the pivot of the jig to get the lip from the outer edge of the driver to the recommended cutout diameter. If you do not want to reset the radius on the jig and route in circles repeatedly, possibly with the cord wanting to wind up as you make those circles, then you can use a rabbet bit and lock the plunge base to the desired height which should match the thickness of the driver’s frame, then just ride that around the circle cut to the cutout diameter recommended for the driver.
Summary – Routers, Bits, and Jigs, Oh My!
So that is it. It really is that simple. Grab yourself a router and get going. Buy your bits. Get some clamps. And get those creative juices flowing. Don’t be afraid to ask the store clerks to help cut down your wood for you. They’ll be happy-ish to help, especially if charging for the service. It really is that easy.
Many people, including myself before I started, think you need this huge plethora of tools to do the fine woodworking, to get the straight edges, and to accomplish the goal. They just do not understand exactly how versatile a router can be. It can do everything! You just have to be creative, understand which bits you will use in your design, and get to work. I’m sure you will thank yourself when you see what you can create.
Also, I didn’t include measurement devices, but do recommend a good ruler or combination square, if possible. I have a 24” blade for my combination square, which can accomplish most of the measurements needed. You may also need a four foot ruler if building especially large speaker cabinets. But that is a story for another time. If you want to find out more, check out the forums for more tips.
Adam J Cain
Author, Attorney (non-practicing), Philosopher, Burgeoning Audiophile and Woodworker
While designing a speaker using a full range driver, I ran into a common problem: the sensitivity shifts upward at a specific point making the higher frequencies output more decibels than lower frequencies. This problem is not unique to these drivers, though. Baffle step is another instance where this can occur. This can cause lower frequencies to drop significantly, which will suck the bass right out of your speaker. There is a solution to these problems: shelf filters.
Lii Audio Crystal-10; Example of full range driver with lower end having less sensitivity
Baffle step is the effect caused by the interaction of the driver and the baffle. It can cause lower frequencies to drop in sensitivity. This is due to a cancellation effect caused by sound wave interference from the point source and the diffraction effect from the cabinet edge. You can compensate by changing how the cabinet and baffle is shaped. But there is also shaping the signal to compensate for the effects.
In comes the importance of shelf or shelving filters. Many know about high pass filters and low pass filters, along with band-pass filters. Arguably, you should always use band-pass for sub-woofers, woofers, and mid-range drivers, but that is for another discussion. One that fewer know about, at least outside of electrical engineering (and even among some engineers), is the shelving filter. The shelving filter boost or attenuate the signal across a period of frequencies to flatten the signal.
Terminology for Shelf Filters
I discovered this filter while perusing the website of SiegfriedLinkwitz (yes, the one who created, with his friend from HP—Riley, the Linkwitz-Riley filter which is a pair of cascading Butterworth filters). But, he did not fully discuss the ways to describe this type of filter.
The Highs and Lows
A shelving filter is first divided into the categories of “low shelf filters” (“LSF”) and “high shelf filters” (“HSF”). This is identified by which part of the signal is being augmented. If you are increasing or attenuating sensitivity of the lower end frequencies, that would be an LSF. If you are decreasing or increasing the sensitivity at the higher end, that would be a high shelf filter.
The Boost and Cut
These are then further divided into two types—a boost and a cut type. So, when you are discussing the type of filter you are using, if you are compensating for baffle step through boosting the low end, you would call it a low shelf boost filter or an LSF boost. If you are cutting the high frequencies, then it would be a high shelf cut filter or HSF cut.
In practice, as regards implementation, you are primarily only using two variations of the circuitry. But it is still important to properly term what you are doing so that everyone is on the same page. Why only two variations? Because an HSF boost is a curve that resembles an LSF cut. Meanwhile, the LSF boost resembles the HSF cut. Why? Because when you raise one, the other end will be lower and vice versa. So, in practice, you are dealing with two filters, but the terminology separates them into four categories. Just be mindful of this in practice.
LSF Boost/HSF Cut HSF Boost/LSF Cut
The other reason to define high and low shelf is so that people understand which part of the signal you are targeting for modification. It will help to convey your goals in the implementation of the filter, which always seems to help when trying to get advice.
Passive Shelf Filter Layout
This section will discuss the implementation of each filter. That is, this will discuss what components are needed for the filter and how they roughly shape the curve, without examining the math.
Low Shelf Cut Filter/High Shelf Boost Filter
To start, we will look at the LSF cut/HSF Boost variant. For this, you will be running a resistor and a capacitor in parallel in the positive line of the circuit path while using a resistor to then run between the positive line after the parallel circuitry to the negative/ground line. See the image for layout.
LSF Cut/HSF Boost
What does each component do? First, the capacitor moves left to right where the shift happens for increasing or attenuating the signal. Second, the resistor in parallel on the positive line raises and lowers the lower frequency sensitivity. Third, the resistor bridging the positive line to the negative line/ground also raises and lowers the frequency sensitivity of the lower end, but it also has a soft effect on the curvature going from the low to the high frequency set.
Low Shelf Boost Filter/High Shelf Cut Filter
Next we have the LSF Boost/HSF Cut filter. This is comprised of a resistor in the positive line along with a resistor followed by a capacitor in series connecting the positive line to the negative/ground line. See image below.
LSF Boost/HSF Cut
The resistor on the positive line moves the entire signal up and down. This makes sense because resistors attenuate the signal. The resistor in the bridging between the positive line and negative/ground line moves the frequencies of the high end up and down. And the capacitor is used to shift where the slope is on the frequency response (moves the slope left and right).
The Math
HSF Boost/LSF Cut Math Equations
V1 and V2 Equation Variables for HSF Boost/LSF Cut HSF Boost/LSF Cut Equation Variables A, fz, and fpLow Shelf Filter Boost/High Shelf Filter Cut Math EquationsV1 and V2 Equation Variables for Low Shelf Boost Filter/High Shelf Cut Filter Low Shelf Boost Filter/High Shelf Cut Filter Equation Variables A, fp, and fz
I won’t go through all of the math. Even though the pictures show the resistors and capacitors used, they carry different numbers from the equation. Just remember that R1 is always in line with the positive line and R2 is always bridging the positive line to the negative/ground line. A is the amount that the lower sensitivity of the frequency response is at. Finally, fz is the lower sensitivity end of the slope and fp is the higher end of the slope.
Conclusion
If you are unsure, you can always open XSim and shape the curve with the rough description given in the last section of this article on what each component in the filter does to the curve shape. You then can plug in what you got into the equations to see them operate in that way, which may help to use it to solve for the values of the components in the future. Sometimes just seeing it work with known variables helps to start thinking about solving for the variables when using the equations. Also, you can cascade these, if you want to do a multi-order shelving filter.
And if you would like to take deeper dives into shelving filters, I suggest you might check here, here, and here. If you instead would like to implement a shelving filter through DSP, you might check out the forums and ask for me if you need help finding it in sigmastudio, or to generally learn more about DSP.
Adam J Cain
Author, Attorney (non-practicing), Philosopher, Burgeoning Audiophile and Woodworker
As with starting any new hobby, a person gets excited. They want to throw themselves into it whole-heartedly. And just like a new relationship, a person just throws themselves into it, especially in the honeymoon period.
Now, if you are like me, you already were interested in some area related to audio, but you do not yet understand the scope of what all goes into audio transmission and how amazing it truly is that we can even do the cheaper implementations embedded into devices and they just work. This isn’t to suggest the cheaper implementations are good. But the more you learn, it is a marvel to see them everywhere. There are many aspects to audio, from the electronics to drive a clean signal to digital signal processing to correction for certain aberrations in the signal chain or aspects of speaker design. Then you have the cabinet or enclosure and woodworking.
As to enclosures, you will find out quickly what a cabinet resonance is. You’ll learn about bracing, insulation, and possibly constrained layer damping. You might even come up with some crazy bracing design of interlocking pieces that also interlock with shelves or dadoes. This is where the mantra comes in: Keep it Simple Stupid!
Many of those advanced woodworking techniques sound and work great. And if you have the skills or a CNC router (like used in the MK Boom build) for sheet goods, this isn’t a message to you. This is to remind people that if you don’t want a project to drag on forever (and designing and building, even without the advanced woodworking will already take a bit more time than you expect), keep it simple!
Tools to Start With
For example, if you are starting from nowhere, you are likely going to get a job-site or contractor saw (or if where you can, a hybrid/fulltablesaw, but talking about starting a hobby within a hobby—woodworking). You will also have to buy a router, possibly a tablerouter, the bits, a circle jig, and learn the skills. The most basic cabinet is a box. Just cut the sides, line them up, glue together. Next is adding a brace, like a window brace, with the walls glued together. Then there is rabbeting the edges to create a tighter fit for the walls. Further, you have dadoes/shelf slots cut into the sides for bracing. Beyond that, you have interlocking bracing that have to align with the other bracing and the dadoes/shelf slots in the internal sides of the speaker.
Each time you make the design more complicated, you add to your tooling costs (meaning getting the tools, creating the jigs, and research on how to create and how to use the tools and jigs) and training costs so you don’t mess it up (especially with the price of wood, even if we may have a slight reprieve on pricing that I hope remains lower; but sheet goods get price cuts after lumber prices, so we have some ways to go).
Advanced Tools
For example, to add dadoes or shelves, you will either need the bit for the router along with clamps or something to hold a straight edge to get a straight cut, a table router, or a dado stack for the table saw (and a table saw able to actually use dado stacks, which excludes job-site saws for the most part). This automatically raises cost and complexity. Further, if using the router and a straight edge, if you get one side or the other clamped at the wrong place, you may not have a straight cut across the plane, meaning your shelves (the bracing) may not be properly aligned when you go to glue up (an accurate square can help with this, so long as your cuts are square and parallel to start with).
These are not hard things to overcome so long as you are measuring seven times and cutting once. But even then, for a beginning woodworker (or even experienced) you will inevitably make a mistake. The simpler the design and fewer tools needed for creating the enclosure, the less chance for a mistake to be made.
Additional Tools
As another example of something a beginner may consider adding, look no further than rabbeting the edges of the sides of the enclosure. Rabbets are easily added by setting up the height in a table router lift or in your edge or other router to run the edges. You can then run every edge at the same time to make sure the heights will match each other as you did it without stop. This is a simple element to add to the enclosure that increases the surface area for glue bonding by 50%, can help potentially reduce air gaps where the box walls meet, and thereby is a practical addition with little extra skill or difficulty being added to the process.
So being judicious in what to add when you are starting is important. Adding little things like rabbets require little extra effort, but carries a great benefit. Dadoes and shelves are nice thoughts, but take a lot more to do properly, regardless of method. Interlocking brace elements that are set back into dadoes throughout the internal system, leave this for advanced woodworkers. If it interests you, build up to it. You will get there, but don’t jump to the end.
Remember, as with all things in life, this is a marathon, not a sprint. Pace yourself and you’ll get there.
Adam J Cain
Author, Attorney (non-practicing), Philosopher, Burgeoning Audiophile and Woodworker
[/vc_column_text][vc_video link=”https://youtu.be/J-ZFdMbfO00″ align=”center” css_animation=”slideInDown”][vc_wp_text]Back in 2012 Edifier bought Stax a high end audiophile headphone company. They continued with that brand, but promised that they would come out with their own Edifier brand. We waited ten years, but they have finally come, the EdifierStax Spirit S3. Were they worth the wait? Let’s find out!
Packaging
Packaging whenever I receive a product. I’m always interested in the type of packaging. When a product is of high quality packaging, I typically get the feeling that the company has really cared about that product. This was especially the case with the edifier stacks as three. These came not only in a hard outer case, but also came in a very comfortable foam case inside. And the headphones themselves were in a third case that is designed as a carrying case to protect the headphones when not in use.
Now even the foam and the case were designed in a way that made you feel like at a fire, really cared about them. The Edifier Spirit Stax logo was stitched on the top of the case with a unique design on the case. And when you opened it up, there was a divider where the headphones would touch each other. That was made of a felt so that they would not scratch. They even included a net where you can put all of your accessories that used velcro to secure it so you didn’t loose any of your accessories. Overall the packaging was vey well thought out and I appreciate they put so much thought into this.[/vc_wp_text][vc_images_carousel images=”25205,25191,25190″ img_size=”full” speed=”2000″ autoplay=”yes”][/vc_column][/vc_row][vc_row][vc_column][vc_wp_text]
The physical design of the Edifier Stax S3 needs are relatively subdued. There. Almost all black with a black leather earmuffs and a black leather headrest. The foam in them is very comfortable and they are designed to be over the ear. The only other thing that you’ll notice about them is there is an R and an L to show you which is your right or left earphone. They also have the Edifier logo on the headband. As well as a really nice carbon fiber inlay on each one of the earmuffs with the EDIFIER logo. And although this is fairly subdued, I really like the design.
The spirits tax as three are a Bluetooth headphone and because of that there are no wires connected to it. However, when you do take a look on the right ear cup, there is a position where you could plug up a 3.5 millimeter cable to plug into a headphone Jack. Now that cable is included. With the headphones when you buy them. In front of that, you’ll see three small little holes. That’s actually the microphone. And behind that you’ll see three buttons. One is a power button, one is a volume up button, and the last is a volume down button. That power button does have multiple functions, such as turning on and off game mode and answering phone calls. The left side really doesn’t have much on it at all, except for a USB C charging port.[/vc_wp_text][vc_gallery images=”25206,25207,25208,25209,25211,25214,25212,25213″][/vc_column][/vc_row][vc_row][vc_column][vc_wp_text]
Battery Life
Once fully charged the Edifier Stax Spirit S3 can last for 80 hours (1500maH battery). However, if you’re in a hurry, you can do a quick 10 minute charge, which should last you about 13 hours, or at least that’s what Edifier claims. I used these for quite a while and never have had an issue with charging. Another excellent benefit is that if you download the app on the phone, they’ll actually tell you what the percentage of the headphones battery life that you have left. I’ve used these for multiple days, even doing. Work out in the yard and have not needed to charge the edifier spirit Stax S3.
Planar Technology Why it differs from your Other Headphones
One of the main advantages of the edifier stacks spear S3 is that they are planar headphones. This is a little bit different technology than your normal dynamic transducer, which you’re probably used to. A planar headphone is a much lighter moving mass, which means that the headphones can respond quicker to music, meaning that you don’t get as much coloration and you don’t get as much distortion. And because of this, they are typically much tighter and can even have a much lower extension without the need of DSP. This is very important when we’re talking about headphones that we want to believe our audiophile grade. The real question here is, did they implement the planar technology correctly to make these audiophile grade?
Sound Quality
This was my first experience with Edifier headphones and I must say I was very impressed with their implementation of their planar drivers. It’s not always simple to implement. Clean our drivers to create a great sounding set of headphones. And this is where I really appreciate what Edifier did. They collaborated with a well known planar headphone manufacturer, Audeze so that they could use some of their patented, award-winning technology (fazor, fluxor and their uniforce diaphram) and in these headphones.
They combined these technologies along with their own implementation of these to create a very convincing soundstage on these headphones. It was very surprising to me to be able to hear things that they hadn’t heard before on headphones. You were easily able to pick up the intricacies. That were hard, if not typically masked by dynamic drivers. Because of muddying the sound. But these were very quick and able to reproduce the sound accurately without fatigue.
One of the things that most surprised me was the base extension. Not only did the bass go down fairly low, but the base was very quick. Whenever I heard a drum or bass beat, it just started and stopped. There was no reverberation when it shouldn’t have been any, and I must say that was something I did not expect. But not only was the bass really good, but the highs were also very good. I was able to get crystal clear highs. On songs that I don’t typically get. In fact, I was even able to hear singers breathing in and out, which I typically would not hear with other pairs of headphones.
The App
since these are Bluetooth headphones, you can’t connect to the app. Now the app is pretty interesting because it does allow you to change the EQ to three different types of EQ. Now, after listening to all the different cues, I personally enjoyed classic and kept it on that. You could also change which type of ear pads you’re using, as well as turning game mode on and off. Now game mode is pretty interesting because what it does is it decreases latency so that you can get the quickest. Signal from your device to your headphones when playing games or even watching movies.
Conclusion
So the real question here is how did I like them overall? When we think about the price point of these, these are on the low end of planar headphones and the fact that they include your Bluetooth is quite amazing. We could do hands free calling, we can do Bluetooth, wireless music. And I must say with all that in mind, these are very undervalued and I think that these might be one of the better values out on the market. If you’re looking for a planar headphones, obviously these are going to be significantly more than a typical dynamic transducer headphone, and if you’re looking to save some money then these are probably. The headphones for you.
There are a lot of subwoofers out there, but is there a best subwoofer? Best subwoofer for home theater? best subwoofer for sound quality? Depending on what you are trying to accomplish there definitely can be a best a subwoofer. Here, I’ll take a look at some different subwoofers I have used and what I think they are really good at. So if you have been interested in a subwoofer, here are some to think about.
The Dayton Ultimax 18 is by far the most versatile subwoofer I have ever come across. This 18″ subwoofer has massive power handling of 1000 watts RMS and 2000 wats peak and it’s generous excursion of 22mm, this subwoofer can really do it all. Seriously, you can do a small sealed, a large ported or even an infinite baffle. This sub is built so well, you literally can pick about any alignment and it will do it and do it well! If you want a relatively small box, you can put it in as small as a 4 cubic foot box and it’ll still tune it down close to 30hz. What to go deeper or lower in bass which makes it one of the the best home theater subwoofers. You can easily do that by by building a box about 11 cubic feet and tuning it do to 16 hz! That is incredible!
And if you really want to go all out, just build it as an infinite baffle. Although, I would recommend dsp for that option. Honestly, there aren’t that many subwoofers that work so well and are so versatile. This is probably my favorite home theater subwoofer. Having said that, if the ultimax 18 is too big, you can get this in sizes 8, 10, 12 and 15. Add in the fact, these are dual 2ohm voice coil, you have the ability to wire this either in a 4 ohm (home use) or 1 ohm (car use) to get the most out of your amplifier.
If sound quality is most important to you, the CSS SDX12 is the subwoofer for you. This 12″ subwoofer utilizes a proprietary XBL underhung motor that offers 1000w RMS power and 2000w peak and an incredible 28mm of excursion. That is the same amount of power the Ultimax 18 can handle with more excursion capabilities…and this is a 12″ subwoofer! But what is even more incredible, is that if you buy the passive radiator version of this subwoofer, you can use an 18.5″ cube and tune this down to 20hz. This is true home theater subwoofer territory out of a very small enclosure. That is pretty unheard of. But what is the most impressive is the sound quality this puts out. It is almost dead silent. You don’t hear any motor noise.
In fact, you keep turning it up, because you don’t hear the subwoofer straining at all. Only until you hear the T yoke hit the top plate, do you realize you are overpowering it. It is incredible. There aren’t many subwoofers that I have tested that have this clarity. And definitely the only one I can think of that has this clarity along with the deep bass needed for home theater. If you are looking for a subwoofer that is great on music and can be good for movies, take a look at the CSS SDX12. I think you’ll be in for a treat.
The Best Subwoofer: Price
ISO 100
The ISO 100 is between $80 to $100….for four subwoofers. That means each subwoofer costs about $20-$25. Now I don’t love the GRS 10SW-4 by itself, but in this build, it is an incredible value. It is probably the cheapest way I know to get true 20hz bass for a home theater subwoofer. Basically, this subwoofer consists of four of the GRS 10SW-4 in an isobaric configuration. By doing this, 4 subwoofers now share the same amount of space you would need for one subwoofer, while maintaining a 4 ohm load. That means you can still use cheap power. In fact, this whole build can run off a 250 watt amplifier. What is incredible, is that this subwoofer, when build will perform similar to an ultimax 18. Watch the video below for more information about it. But if you want cheap bass that can dig deep, the ISO 100 is your sub.
Let’s be honest, I love the tang band W5-1138smf. It is by far my favorite small subwoofer. Why? Because it can dig deep, with authority in a small form factor. This is the same subwoofer that I used in the famed Dinas and in my redesigned Voxel build. That is due to the fact, that these can get loud and play really well, all the way down to 35hz. For a 5 1/4″ sub that is amazing!
This sub can be used in a lot of way, but one issue with it, is it can really move a lot of air. So I found the best way to use this with a the VoxelPassive Radiator version. In this version, I add a passive radiator which takes away any concerns with port noise (chuffing) due to the air being pushed out of the port. This makes this subwoofer an absolute beast. When I first played the Dinas at Midwest Audio Fest a guy thought I was punking him. He thought for sure I was hiding a 12″ subwoofer somewhere. Keep in mind, these were being played in a huge warehouse and he still couldn’t believe the amount of bass they put out.
So if you are looking for a small subwoofer, take look at the w5-1138smf. ANd if you want something fun to do with them, check out the Dinas or the Voxelpassive radiator. I think you would enjoy them.
What’s your favorite Subwoofer
So you’ve heard my favorites. What are yours and why? Leave them in the comment section or the forum.
The new Dayton AudioMax-X 15″ Subwoofer, the MX15-22 is now available. I plan to get one, but before I do, I thought I would share some ideas for one of the best subwoofer box designs for deeps bass. As always, the subwoofer box design is the most problematic. And I honestly thought the MX15-22 could be really hard due to it’s High Excursion. Especially when you are trying to design the loudest subwoofer box design. Typically high excursion subwoofers will have some issues with port noise when you design your subwoofer box. Or at least maintaining an inaudible port noise at full volumes. This was especially a challenge when I designed the Dinas. But if all the specs are correct on this sub, here is a build option.
*when I say loudest subwoofer box design, i am talking about low end extension without the aid of dsp.
Home Theater Subwoofer Design
Subwoofer Design
ChevyChev ported subwoofer design tuned to 21hz in around a 5.3 cubic foot box. This should be a great subwoofer design for deep bass. Simulation is with 800w
Projected Response of the Subwoofer Box:
This Max15-22 has a projected F3 of around 20hz. This is exactly what we want for the deep bass that is necessary for a good home theater subwoofer.
Excursion
With 800w, the subwoofer does have a problem excursion below 18hz. Which we can take care of later. *In general this is an issue with all ported subwoofer box designs.
Port Velocity
Port Velocity below 26hz does go over out target of 17 m/s and has a first port resonance of 226hz. This subwoofer box is using a slot port of 15″ wide by 2″ tall and 30″ deep. Some people might be okay with this, as the amount of sound there is negligible. But I think we can get this down a little more.
Most of the perceived problems of this subwoofer box design will go away with a simple high pass/subsonic filter on the subwoofer. By just using a second order centered at 20hz, all your excursion problems go away and your port velocity doesn’t go over 17m/s except between 17-25hz. Here it peaks at 20m/s. And with a rear firing port, I don’t think this would be an issue at all. But if you were concerned, you could increase that to a 4th order. Why is this so important? Most home theater plate amplifiers have a 2nd order high pass on them centered at 20hz. So you wouldn’t have to do anything. And since this can take the full 800w, it will be the loudest subwoofer box design (assuming you want a flat response that is).
Suggested Amplifiers:
The amplifiers are going to be the most expensive part of this build. But if you want your subwoofer design to really shine, you will want to pick one that best suits your needs. There are a lot of pros and cons to each amplifier. I’ll try to break it down for you.
SPA1000 – This would be the most powerful plate amplifier that would get you the most SPL and deep bass out of the MX15-22 right out of the box. It is a class AB amplifier. The biggest con here is the expense. It is twice the cost of one subwoofer and will only work for this subwoofer. But it does have really good dynamic power and will help your subwoofer see it’s full potential and has a 20hz 2nd order dedicated high pass. It also is a sealed amplifier, so you wouldn’t have to design a separate amplifier compartment in the subwoofer box. However, I still suggest it.
SPA500 – This is another Class ab amplifier, which some people prefer. This would only give your subwoofer 500w of power and more dynamically. It also has a very limited parametric EQ, but might help out if you have a huge peak due to a room mode. This is a cheaper option, but there are less expensive and maybe even better amplifiers out there for the price. This does have a 20hz 2nd order dedicated high pass as well. It is also sealed, but I would still recommend a separate amplifier compartment.
SPA500DSP – This is a class D amplifier with built in DSP. This will allow you to pick your subsonic filter, dsp your room modes out using a laptop with usb. You can install limiters, phasing and eq. This would be for someone that really wants the best sound out of their subwoofer and has a decent calibrated microphone to set it up. It is probably my favorite plate amplifier. This is not enclosed, so I would recommend a separate sealed enclosure for this. This can be built right into the subwoofer.
SD500 – This is the cheapest option. It is a class D amplifier. It has not tested as well as the Dayton Audio AB amplifiers when it comes to dynamic power. So do not expect much more out of it that the 500w even during short bursts. This is not enclosed, so I would recommend a separate sealed enclosure inside or outside the subwoofer box. This can be built right into the subwoofer design we created..
Recently Sound Advice had a DIY boombox competition. The goal was to take a premade boombox kit from Parts Express and transform it aesthetically to just wow people. I ended up with the MK boom, an inexpensive $130 diy boombox kit. It was small, so I had to get creative. So for this, I used Epoxy and a blue powder to create this beautiful look to it. After that was finished, I back lit it with LED’s. Overall, I was very happy. It seems others liked this $130 boombox transformation, as I ended up winning the competition. Let me know if you have any questions. But for now, here are some pictures and the video of the build process.
The MK Boomboombox isn’t in itself a unique design. It isn’t like the fully waterproof boombox or like the fun Emoji Boombox. This was more like an ammo can boombox. You really had to work with the structure already given to you to make the unique design. That is what made the MK Boom Boombox so hard to design. What could I do that was so different, that could make this $130 MK Boom look to be worth so much more? That is when it hit me. You don’t see many boomboxes with an epoxy pour. And definitely not many with an LED lit epoxy pour.
For this, I decided to use my CNC. Now you could make jigs to make this work, but I choose to use my CNC design software and have it cut this out. I would love to say it went smoothly, but I had to cut 5 tops out before one worked correctly. Even when the machine is doing ti, there can be issues.
MK Boom Challenges
Besides the top taking numerous cuts before ti worked out. There were a few more challenge. The first was how to add led lighting. I had two options. First, I could using the 12v output on the battery pack itself. Each of the Dayton boards have this 12v out, so it is easy to run an accessory. However, by doing this you have to run a power switch between the lights. Typically you could just use a DPST switch. However, the power on the Dayton board doesn’t work like a normal power switch. SO I couldn’t use a DPST.
Another option was to take the MK Boom’s power input and split the power signal coming in. Since this comes with a 15v power supply, you would want to run a step down to step down the power to 12v.
In the end, I choose neither of these options and instead, just ran the lights to the power switch. Which mean that when the battery is charged or the MK boom is plugged in, the boom box is technically on. But that didn’t really bother me.
MK Boom Final Thoughts
The MK Boom is a decent starter DIY Boombox that you can really tailor it to your style. It is a little harder to work with since it is so small. But you can get creative and make make something. Not to mention the wiring is all plug and play, minus soldering the crossover to the amplifier board.
The sound quality isn’t the best I’ve heard, but it is adequate at the $130 price range. It doesn’t go as deep in bass as some and the response can get a little sloppy. But over all, I think the MK boom is a fine kit for someone to start making a DIY boombox.
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