March 14, 2021 at 4:32 pm #12950
I like the price and the performance of these speakers, so am thinking of using them for my first build (and if I think I can do a better cabinet later, I can move them to that).
So, my thought originally was two towers with 1xWom165_vMS each, 1xMid120_vHE each, and a twt28_vHP each. For the Bookshelves, 1xWom165_vMS each and 1xtwt28_vHP each.
For a center channel, I’m thinking 2xWom165_vMS paired with a Twt25_vHE (currently being redesigned), but may need to ask about 2xWom145_vMS to pair with a twt28_vHP to get the sensitivity right for what is available now.
I was wondering if anyone had any thoughts on that.
Now, currently the mid120_vHE is not available for sell. This means that although they could overlap the twt28_vHP with a 2 crossover, it really will not hit the mids like I wanted. I could throw a twt30 in there to reach low enough to hit those mids (they used an example of a bookshelf with the Wom165_vMS, the twt30_vMS and the twt12_vHP), but I really would prefer an actual mid so that I’m not interacting on crossing over with that second impedance peak seen on the twt30.
Although I could take the crossover point to 2,000Hz on the Wom165_vMS, my goal is to try to cross lower, like by 1300Hz. That is where the off axis charts show the first divergence, although it tracks really closely up to 2,000Hz (which is why I selected those areas, although I did note in their chart on their website there being an impedance bump around 1100-1300Hz, although that may vary by speaker).
I would substitute the Wom120_vMS or Wom145_vMS for the mid, except the first has an 87dB sensitivity and the second has an 88dB sensitivity, with the Wom165 and the twt28_vHP having 90dB. Sure, I’m probably nitpicking at the moment, and that range may be lifted a bit in the mid with the roll off of the 165 and the pickup on the twt28.
My goal with these is to attempt to get fairly flat lines with little coloring, along with great off axis performance. This is why I paid a lot of attention to the impedance values and the off-axis performance at 30 and 60 degrees. I really like the performance of the twt12, but aside from not being for sale through their distributor, it is an 87dB sensitivity tweeter, meaning either pulling down the other speaker’s sensitivity or doubling up.
I’d like any advice anyone has for me.
So far, this is what I’ve got for my winISD modeling with the 6.5″ in single and dual driver configurations, along with a quad Kartesian 4″ sub:
March 15, 2021 at 3:52 pm #12964
So, the F3 on the 4xSub120_vHP-F that I found is around 54Hz using the box tuned to 50.93Hz and the volume at 0.310 cubic feet.
I did, however, get the 6.5″ Wom165_vMS down to 85Hz with an F3 of 64Hz when tuned to 61.75Hz.
If assuming a sub will handle the 20-80Hz range, this could be a good home theater solution. Either that or adding a sub to the towers to handle the bass would be needed.
Still learning and playing. Also set the voltage input to 2.8V on these speakers.
Edit: To give an idea, that is roughly a little bigger than internal dimensions of 7.5″w x 8.45″h x 7.5″d, excluding the port which is .4×7.5×6.31 (length), the volume of the driver, and the volume of the brace (so it will be a little bigger than this and can be adjusted to preference in the next design phase). This results in an air velocity of around 13.776m/s. If you chamfer the edges, even though already where you should not have issue with the air moving, you will have a really nice looking bookshelf. That is for the single 6.5″ driver bookshelf.
Edit 2: I changed the port length after looking at 80W. I do not know what the RMS of these drivers is, so wanted to make sure that would be fine. But now the port does wrap the bottom and back of the enclosure.
March 16, 2021 at 8:52 am #12974hifisvenParticipant
@ajc9988 I like how you are diving right into this. I am not experienced, so I refrain from commenting on your design (though it sound well thought out!). Will be my first build as well and I am clearly well over my head, tbh. That said, I love the Kardesian speakers from what I see. Only dilemma I have is that 2 out of the 3 drivers I eyeballed aren’t available,… the WOM250 and the MID120. Although I wish they had something like a MID165 instead of MID120 anyway. So, back th drawing board. Good luck with your project!
March 16, 2021 at 2:11 pm #12977
@hifisven – Thanks. I LOVE to research. I just finished a big annual project, so this is going to be my reward. lol. Also, I have a little bit of spare time until the next project rolls in, so I’m using it to learn.
I will be posting more photos later today, as the French site has additional measurements that will help, such as XMAX (maximum distance the cone can travel before it basically bottoms out or comes completely out of the voice coil positioning with the magnet, where it can then be nonlinear or even tear itself apart), nominal and max power, etc. I question the Le and EBP numbers due to them being the same for two woofers and a tweeter, same with dual voice coils for everything, but I will be going through and adding the information to a separate spreadsheet this morning.
As to building a home theater three-way, I am now at deciding to do the following, most likely:
Floorstanding: 1xWom165_vMS; 2xWom120_vMS; 1xtwt28_vHP. Then have the 165 do 82Hz to around 800-1000Hz, have the 120s do from 800-1000Hz with a bandpass to around 3000Hz, with the tweeter doing above 3000Hz.
Things I would potentially want or change: I might want to add an 8-12in sub to the build. I would prefer 8-10in to keep the chassis from getting too wide. That would be purely sub-80ish Hz range. Next thing would be to add another smaller tweeter which has good above 8000Hz behavior with less separation of off-axis behavior. This tweeter is not bad at all, but that would allow the sound stage to be even better with this build.
Center: 2xWom120_vMS and 1xTwt28vHP. The two 120s give a good response with my design down to 100Hz with an F3 (3dB lower from the average transfer function) of around 75Hz. Since these already cross at 3000Hz with the tweeter, that makes this a decently small box to have under the TV right in front, while providing good coverage of the range being flat from around 100-8000Hz before the off-axis starts to matter.
Bookshelves: This will have 1xWom165_vMS, 1xWom120_vMS, and 1xTwt28_vHP.
Now, the 120 is less sensitive than the 165 or the 28. That is why I use two in the center and the floorstanding speakers. So, how do we deal with the dip from around 1000-3000Hz? Some would say turn into the skid and allow there to be a dip in the mids on sensitivity slightly so that it works with people that consider the range to be harsher. I may do that. Another way to do it would be to use the tails from the 165 and the 28 with a single order to use the roll off to bolster the frequency range of the 120. Another possibility is to do that while changing the frequency at which they crossover for the bookshelves along with a longer roll-off so that any dip is small and practically unnoticeable. I think that last one is the road I’ll be going down.
Also, although emailing the distributor said they did not have the Wom250, their website has the Wom250_vPA listed. https://en.toutlehautparleur.com/univers-des-marques/kartesian-speakers/woofers/speaker-kartesian-wom250-vpa-8-ohm-267-mm.html
That 10in would absolutely blow my budget. Also, I would recommend crossing it before or at 400Hz. At 400Hz, aside from the impedance bump which shows a dip there to 500Hz, above 500Hz is where the off-axis starts to diverge and where the speaker shoots way up on sensitivity.
Now, I do agree with you that I wish they had their mid120 available. But the WOM120 is a suitable replacement if using it as a mid driver.
If I may ask, what are you designing your speakers for? Music listening or Home Theater? Mine is HT, as you could guess with the 5.0 system. I’ll deal with the sub later. But that is also why I am less worried about the 20-80Hz range. For music, I’ve seen many mention that is more 40-80Hz, while the 20-40hz is seen more for cinema. That being the case, although I have a decent design, some may not be happy with how high the lowest point is on my floorstanding or bookshelf speakers will be (around 82Hz). That is why I am considering a smaller sub to add to the floorstanding (bookshelves will have to make due). I am also considering a shortlist of tweeters that *might* perform alright regarding off axis above 8000Hz to keep that tight. But the sub would definitely make my first crossover be a 4-way. Talk about ambitious, amiright?
Edit: considering using the Dayton Audio Rss265HO-44 10″ sub (https://www.parts-express.com/Dayton-Audio-RSS265HO-44-10-Reference-HO-DVC-Subwoofer-295-463) to fill out the 20-80Hz range on the floorstanding speakers. That would give relatively flat response from 40-8000Hz, including off axis, all being around equal sensitivity. I am fully open to suggestions on subs for the floorstanding speakers.
March 16, 2021 at 7:01 pm #12981hifisvenParticipant
@ajc9988 Wow! The way you describe it, I can already hear the sweet sound coming out of your system! My build as you guessed will be stereo removed link I am not much of a tv guy and -as a fact- haven’t owned a tv for the past few years. I was really excited to see the Kartesian line, even though I feel there are few voids to fill, especially with the items not even currently available. But that’s the beauty of innovation,… you sometimes encounter hiccups. So, given the slight squeeze in supply, I figured I’d take the COX165 for mid/high and add the WOM250_vHE for the lows, so a 3-way. But since they might not be able to supply the WOM250-vHE, I’d have to use the WOM165_vHE as a substitute. Crossovers would be somewhere around 200/2500 or so. Will still need to evaluate.
Anyway, probably not the most sensible combination, but I wanted to jump on the Kartesian bandwagon and take advantage of Nick’s generous offer to co-ordinate a group order.
March 17, 2021 at 6:06 am #12988
So, I played around with the Dayton RSS265HO-44 (only issue is driving 2 Ohm, but that is a problem later in the design process if I do not find another speaker worthwhile), the Kartesian Wom165_vMS, and 2 Wom 120_vMS. This is what I got:
You would be hard pressed to get the theoretical curve much flatter than that. @123Toid , I rewatched your video discussing using WinISD and you mentioned wanting the first port resonance high enough. Here, I would have it high enough for the 10″ sub, but am unsure if it will effect the other speakers on their first port resonance. I also selected the system input power by first putting in the RMS for each speaker type, then lowering the wattage of the other speakers to match the dB rating of the RMS of the lowest common denominator, in this case the 2xWom120_vMS.
Also, is there a way to model the drivers of different types in the same cabinet space? As I take it this would be building in the individual compartments in the tower. Is there any way to model the tweeter? And do you have opinions on eminence designer, soundeasy, or bass box pro you would be willing to share for box design?
Did some maths and to do this, the internal dimensions of the box would need to be 47in (H) x 10in (W) x 12.1 (D), excluding internal compartments. This would mean wrapping the 38.87in vent from the bottom front to the back and up the back of the sub compartment, the 6.5″ speaker would need a back pulling it in from the depth to only have close to 5.43″, excluding the 14.79″ vent, which also means this vent will possibly have to turn at the top of the 6.5″ enclosure toward the front. And for the 2×4.7″ drivers, it only needs a 2.8″ depth, meaning the 13.28″ will go in, then climb the 10″height for that internal enclosure, and may or may not need to turn (possibly not since it adds the half inch of the vent plus the thickness of the building material, any dampener inside and bracing, etc.).
All of this is before looking at wavelength alignment, though, phasing, etc. As I mentioned, I am new. So still have to figure out more of the speaker placement and how I want to accomplish my goals. That also is a triple port design. I also do not know how loud the tweeter can go at RMS, which may further limit the wattage sent to these speakers, which could mean I may be able to shorten the ports relative to the total maximum dB for which I am designing the speaker.
The center speaker is pretty easy as it is just the two 4.7″ speakers, so internal needs roughly 15 x 5 x 3.73″ with a vent length of 13.28, so it will run from the front to the back and up the back decently easily.
As for the bookshelf with 1×6.5″ and 1×4.7″, I would like to do a single port, but would need to do more to figure out the proper port length with both drivers in the same compartment.
Edit 2: and that is excluding the height for the tweeter, which is another 2.5in” to mount. So I’m estimating a 4′ 10″ speaker, roughly, with just under 3″ for the ports plus the thickness of the material (possibly 1″; don’t know how thick is needed for maple plywood (not set in stone)) separating each compartment. That’s kind of a big boy, at 4’10” (H) x 10″ (w) x 17″ (d). And that is before the speaker spikes. (rough estimate in my mind before putting it in sketch up).
Edit 3: I redid it so that it would be 12″ internal. Not including the displacement of the drivers, the bracing, and the padding, but accounting for the thickness of the vent as currently imagined, that would make the box 48.75″ (H) x 14″ (W) x 17.1″ (D). That would make this roughly inline to the size of a Rebel F328Be (except my ports will be on the front, my box won’t look as nice, and my design requires a 4-way cross). I might add to the height for the bracing and speaker displacement and dampener. So it will still be taller. But better than being at 5′ before compensating for all of that.
March 18, 2021 at 12:36 am #12996
So, I found the 8Ohm variant of the Dayton sub, version RSS265HF-8 ( https://www.parts-express.com/Dayton-Audio-RSS265HF-8-10-Reference-HF-Subwoofer-8-Ohm-295-442 ). If making it perfectly flat, it doesn’t perform as well as the 2 Ohm variant (HO-44), but, if willing to allow it to perform up to 0.246dB over zero for the transfer function, and increasing the volume of the section of the cabinet to the sub, something amazing happens . . . . You get a pony! lol. Instead you get an F3 of 19.25Hz. That’s right. Of course you will need an infrasonic filter because the sub will shred itself in the 18.10Hz mark (cone excursion), but other than that, you get down to 29.93Hz at F0 and cross the 20Hz level at -2.249dB. I’d say that is worth designing the extra space in the floor speaker for, along with barely any dB over a 0 transfer magnitude.
So this floor standing speaker is shaping up to have some decent performance, even if the 4.77″ speakers will limit it to 106.2dB. With the second speaker, that should bring it to 109dB. With the bookshelves and center, that will be more. Then eventually building the stand alone sub.
With the sub around 200W, 2×4.77″ pulling 50W each, a tweeter likely pulling 20W, and the 6.5″ pulling 50W, this speaker should be around 370W, give or take, for nominal full load. That is 740W for the two floor standing speakers. 120W for the center. Then probably 100W for the bookshelves. So designing a little over 1000W system (without a sub). I should check really quick on the bookshelves because the 4.77″ is the mid, but is about 3dB weaker on sensitivity than the tweeter and the 6.5″ woofer.
One question: When you have two drivers of the same type in WinISD, do you enter the RMS for System Input Power or do you double it? It seems like you do not double it, but wanted to ask.
March 18, 2021 at 4:24 am #12999
Some starts on the Center and two Bookshelves. For the Center, it is basically taken from the tower, just ripped into a smaller case because that is all it needs. I’m using 1″ as an estimate for the thickness of the walls. Still haven’t compensated volume in the box for any of these designs as of yet.
For the Bookshelf, since the mid (Wom120) doesn’t have to get low, I threw it in a non-ported compartment, have the 6.5″ ported, and have the tweeter thrown on there as well.
To put this into perspective, the Center will have a two-way crossover (at around 3,000Hz), the Bookshelf will have a three-way crossover, somewhere around 1,000 or 1,200 and at 3,000Hz, then the Towers will do a 4-way (or a 5-way if I find a tweeter that can offer great 60 deg. off axis above 8,000Hz) with the crossovers around 80 or 100Hz, 1000 or 1200, and around 3,000. Each case grows in complexity and grows in skills needed to accomplish the task (along with build size).
The bookshelf will be around the following:
7 (W) x 20 (H) x 11-5/16 (d)
The Center will be around:
5 (H)x 16-7/8 (W) x 7-1/8 (d)
(Ignore the error in the spreadsheet from a copy and paste on the Bookshelf dimensions, it is 7, not 14, inches)
I may work on getting the Bookshelf smaller, like removing a compartment to have the tweeter and the Wom120 in the same compartment, maybe put them almost touching. That can cut some height on the bookshelf. Still have bracing and displacement. I suppose I’m going to have to start selecting a CAD program soon to start figuring out the actual specifics….
Also, I was right. In the bookshelf, to keep from overpowering the Wom120, you have to lower the max on the Wom165 to around 25W. So that plus the 50W Wom120, plus up to 20W on the tweeter, the speaker is shaping up to be a 90-95W speaker tuned to around 103dB under load (theoretically). The center and floor standing are tuned to 106dB. I figure this should be fine in theory for the supporting role of surround speakers and sitting closer to them, on average, than the other three speakers. Otherwise, I would need 2xWom120s per bookshelf and that grows the size by 5 inches (insert that’s what she said joke here). Now, if willing to have another four or five inches (minus one by making the tweeter share compartment with the two mids and any you can save packing them close together), you can make this a nearly 2 foot Bookshelf. It also will hit 106dB, meaning a pair of the bookshelves with the 2xWom120s should be able to hit 109dB together.
The bookshelves will lack bass, but for those that want a small bass box, I believe 123Toid recently made a video just about that, going down to 60-65Hz, lower than the 100Hz of the 6.5″. Or you can wait for his project with the 4″ sub from .Kartesian. The sub may not hit the sensitivity of how loud the bookshelves are if going with a small cube, but it would greatly supplement what is there giving a better experience.
March 25, 2021 at 9:44 pm #13060
So, the spreadsheet on vent length is wrong, so the volume may be wrong. I will recalculate it later, but figured any amount could be filled in with acoustic damping material to make up the difference. I did measure and the vent length is correct, but my spreadsheet has the wrong lengths for the vent parts. Need to refine my equations. Doesn’t help that when you put in a limit formula without the specific calc formula (just it being recursive to the point of the limit), that excel freaks out and says no. But that doesn’t fully explain how far off the vent lengths are.
Either way, if I have to compensate for volume, I’ll do so with internal damping material.
Still do not have the braces that run the walls in that diagram. But still this gives an idea.
This is a big boy. If you add another 1.5″ on the base (with the existing 1″), you wind up with a 14″ (w) x 59.6875 (h) x 22.5378 (d). That is mainly so large due to the subwoofer in the enclosure.
Just double checked the vent volume with the new lengths. The cubic inch was within 1 cubic inch of what was in the spreadsheet, which could be rounding errors to the fractions of an inch (trying to fit it to 1/8, 1/16, or 1/32 of an inch instead of a tenths, hundredths, thousandths). I’m assuming the same with the other spaces but will check tonight.
For the top chamber, the walls are pulled in 2.25″ on each side of the chamber for the 2xWom120s and the Twt28. All three of them will be in there, with the tweeter sandwiched between the two woofers. The edges of the two woofers will be over part of the frame and the separator between the top and middle compartment. This was part of the compromises to get the internal area correct. That was tough.
So, you have a vent, Wom120, TWT28, Wom120, Wom165, vent, Dayton Reference series 10 inch RSS265HF-8, and the vent at the very bottom. So three vents. The tweeter in the middle was both to try to make it closer to ear level when sitting and to not have it too far from the 165mm woofer.
Article used for bracing: https://www.audioholics.com/loudspeaker-design/detailed-look-proper-loudspeaker-cabinet-bracing
So the vent boards being doubled of the shell act as bracing. I still have not put in the two square bracing planned in the sub area in addition with open centers in those braces, which are 2″ x 1.5″ and run the outside of the inner area.
Edit: Fixed the equation to get it to tell the correct length of each length of the vent for a single 90 deg bend.
I’ll need to double check I entered the numbers in correctly, then come up with the precise translation to Imperial (fractional inches) to then come up with the cut list and precise measurements to tell everyone. It is a fairly basic box.
Edit: To let people know, I calculated the volume for the horizontal braces with it running against the side of the inner vent, not in the space above the inner vent. If you want to run the brace higher up to touch the back of the speaker, then the volume would need recalculated, and thereby need to adjust the size OR reduce the damping material, which I assumed around 10% of the volume of what was given by WinISD.
Edit: update –
The distance from the acoustic center of the mid-drivers/tweeter to the Wom165 is 10 31/32″ (10.96875″). A full wavelength for 1250Hz is about 10.8″. That should be just enough to keep things just about right for the crossover. The sub to the other speakers isn’t really an issue, as 100Hz is 135.04 in. for a full wavelength. Just have it higher in its segment because I didn’t want it hanging by itself too low and look off.
Edit: A little more 3D. Also, the top compartment with the two mids and the tweeter will have 2.25″ walls on each side, bringing it into 7.5″ across. I figure just glue three .75″ plywood together on each side, then glue that to the walls. So the mids and tweeter will have a fairly solid enclosure. Especially since that also will glue to the front.
*These plans are for Personal use only. If you want to resell these, contact me first.
March 27, 2021 at 7:40 pm #13070
So, the Loudspeaker Design Cookbook 7th Edition (“LDC7”) came in yesterday, so going to take the weekend to take in key chapters. I am also going to redesign and draw up in sketchbook using some of my take-aways.
I am also going to draw up another design with back-firing vents. This will allow me to drop the height of the speaker to 4′. I will then check to see with the 4′ design (and 2′ deep) if I use any fewer sheets of plywood to accomplish the build.
I am also using the dimensions of the building materials I plan to use. I will be checking the parameters for whether and where to use a constrained damping layer (“CDL”).
On my research on CDL, aside from it being less than well documented, it is that green glue is NOT the solution, generally speaking, for cabinet design. Why? Although Green Glue is a viscoelastic polyurethane compound, it does not setup hard enough for this purpose (stays too liquid for the application). Further, their application technique is to wildly apply it on the sheet, instead of applying in a uniform fashion. As such, it does not have even results, has trapped air pockets, etc. Even if you got the 5 gallon bucket for over $300 to roll on, due to staying too liquid, it will not be appropriate for this use. (edit: The manufacturer does directly state their solution to be able to be used in a vertical orientation, which alleviates some fears related to setup. But it dries, on average, to 0.5mm and has a temp usage of 65-85F, which is much more constrained than many other building materials that can go sub-zero to over 100F, although they do often mention effectiveness is less as it gets colder.).
What that leaves is other types of Damping Compounds (DC). These come in different types in different industries. What was seen on Tech Ingredients’s Voight box was DC-30, a polyurethane paste material spread about 1mm thin. As the LDC7 pointed out, some of the automotive dampers may gas off and may not be suitable as they could damage drivers. This seemed to be referring more to dampers that can be rolled on like paints (in fact, there are what were called “sound paints,” with the Acry-Tech Acoust-X being one such material. https://www.parts-express.com/Acry-Tech-Acoust-X-1-Gal-Absorption-Coating-Paintable-Dampin-260-105 ). Then there was cheaper damper layers (compared to isodamp) like Audiomute Peacemaker which is a 6mm constrained layer to be placed between two pieces of wood (made for flooring, but what matters is the damping coefficient). That is 2’x25′ for $125 I think it was, or $2.50 per foot.
My take away on this search is that what matters is finding a descent viscoelastic material (silicon is not always visco, even though elastic) that can dampen while gluing the two pieces together. Certain types of rubber (possibly certain types used in roofing), certain polyurethane foams, pastes, and similar can be used (such as DC-30 damping compounds, although some of those are only to be used on metals, so please pay attention to the manufacturer’s statements of suitability). Also, remember, not all damping compounds are made to be used between two harder layers. Also, some of those compounds do not fully set and are not made to be used in a vertical orientation. You can find that in damping compounds made for flooring (including some self-leveling compounds), for example, where due to the horizontal nature, you do not need the material to fully set, where vertical would cause it to run out.
But, as I learn (and create more possible designs), I will keep posting.
Edit: I am also looking into Bitumen Rubber, like Betta by Gripset, as a potential product, or liquid rubber. I have to do more research on their properties, though, before I attempt those.
March 28, 2021 at 3:53 pm #13075
Good morning all.
Here is the 4′ version of the box. I had to have the bottom and top pieces hang over the front baffle and back. The reason why is simply for cutting up the plywood. With the dimensions used, you can cut a 4′ x 8′ in half, then the 4’x4′ in half to get the two side panels, while still being able to cut the front and back panel out of the other 4’x4′ piece. This will potentially drop the plywood sheets needed for construction if good planning is used (or possibly only needing a half-sheet or something like that instead of another full 4×8). Ignore my scribbling at the edges on the spreadsheet. That was me trying to convert some dimensions to the closest fraction of an inch to draw up the model in sketchup.
I packed the front speakers as close as possible in a MTMW-S configuration. I could move the sub up to right under the 6.5″ woofer, but chose not to based on the wavelength of the sub’s range, worry of vibrations coloring the compartment for the 6.5″, and because I want to inset the speakers (fine for the top ones, cosmetic for the sub), I planned the braces behind the inset so that you could drive longer screws at the top and bottom of the speaker to make up for the material removed from the front baffle, allowing a mechanical connection to not just the baffle but also the braces. Considering the inset requires a 3/8″ amount to be removed from a 3/4″ (actual 0.703, incorporated actual into the model) piece of plywood, there goes half of the baffle material to inset the sub. But, if you have longer screws at the 12 and 6 O’clock positions, this may make it a bit better. Also note, it is not necessary to inset your subwoofer. This will be fine without an inset, and I may even decide against insetting it for construction due to how much material is removed. With how much further down it is currently set, it not being inset should not effect the diffraction or create issues with the 6.5″ woofer. So, just to reiterate, the outside would be 2 2’x4′ pieces, 2 14″x4′ pieces, and 2 25 1/4″x14″ pieces for the top and bottom. Then, you have all of the internal pieces and bracing.
I also added a brace to the 6.5″ speaker section. Considering the WTW area is still pulled in by 2.25″ on each side in the top, those thicker walls or putting braces on the inner walls to the outer walls should be enough without putting a brace inside, although you still have to use some damping material inside the area.
1) I didn’t add the rear slots on sketchup yet for the vents.
2) Due to cone excursion, you won’t want to run the sub any higher than equal SPL to the other drivers, limiting to the Wom120 RMS.
3) You will need to setup an infrasonic filter on your crossover to prevent the sub from harming itself below 19Hz.
4) The braces used for the sub go in 2″, the brace for the 6.5″ woofer go toward the center 1.5″. (see spreadsheet).
5) this uses the same square with no center showed in the 5′ design. What is envisioned is cutting the square, then cutting the inside out of it, then gluing two of those squares together to create a 1.5″ (reality 1.406″+ glue or 1mm of constrained material) brace. That way the square is solid and not joined by 4 pieces glued together. This should add a bit more rigidity to the square.
Any questions and comments on the design are surely welcome. As I said, I am new to this, so feel free to ask why I did something or tell me if you see something that seems wrong.
Edit: Also, after I design the bookshelf speakers (next), I will design a more narrow version of the floor standing speakers without the sub in it. This will be more slender and still use the MTMW configuration. That should please some who would want something about 7″ wide. Should also be easier on the wallet as far as construction materials.
*These plans are for Personal use only. If you want to resell these, contact me first.
March 29, 2021 at 6:04 pm #13077
So, here is the design for the center, which also could be used as a bookshelf speaker or to just produce 5 of them and use those as 2-way 5.0 system using way less wood and able to be placed more easily around the room. They should have around 106dB RMS. Do not go over 50W per driver for the woofers, as they are not that far from cone excursion with this enclosure. You’ll want to put in the plumbing (meaning the crossover and the ports in the back) before you glue on the face baffle, which I designed to be glued on last. These are 120W speakers, so they should be near to maxed out on many audio receivers on the market and should fit well with receivers with 80-125W RMS per channel. Since the drivers selected are 8 Ohm nominal, these, once ran in parallel for the drivers, should be 4 Ohm speakers, if I picked up how that works correctly (if not, PLEASE let me know). Here is the spreadsheet, the cut list, the driver and tweeter selection, and the winISD information for the speaker design. This is assuming use of plywood (since home theater system, figure start there and stain and seal). Also, with the size, the extra cost should not be as bad, while getting extra stiffness out of the material.
Edit: I did forget to mention, you will need the low-end crossover filtered. The reason is that the Xmax winds up exceeding at around 60.29 Hz (or just under that) at about 9dB down from max volume during RMS use. Also, this assumes air pressure at sea level. If in the mountains, like me (around 4500ft), you have to try to not run these above 37W per speaker, or else another Xmax point appears.
You still have 105dB, so nothing to worry about there. But I did feel the need to mention the nuance here in case people, when getting to the building of the crossover stage forgot to check for Xmax and compensate in the crossover for the safety of the speaker.
*These plans are for Personal use only. If you want to resell these, contact me first.
March 29, 2021 at 9:50 pm #13079
Bonus: if you are cutting out 5 of these speakers, this is the cut layout that assumes a 1/4″ spacing between edges of the boards. That should allow for blade width + if it kicks a little bit at the edges, so that you can correct those or sand them to final length without too much worry. This all depends on your tools. Please adjust if needed. Just figured I’d lay it out since this may be the way I wind up going (and then use what I didn’t spend on the Wom165_vMS to then build 2 more of these for a side room, which should just about be doable with the remaining part of the sheet of plywood).
*These plans are for Personal use only. If you want to resell these, contact me first.
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