Blog Forums DIY Speakers and Subwoofers ISO 100 Build – 20hz for under $100

last updated by nickd 10 months ago
11 voices
85 replies
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    • #12711
      123toid
      Keymaster

      Parts Needed

      Box Dimensions and Cut List

      External Box Dimensions – Using 3/4″ Material

      • Height: 24″
      • Width: 30″
      • Depth: 18″

      This box uses 3/4″ material.

      Sample Cut List:

      • Front and Rear Baffle: 30″ x 24″
      • Top and Bottom: 30″ x 16 1/2″
      • Ends: 16 1/2″ x 22 1/2″

      Ports

      Ports. You will need 2 of the Precision ports. If using the precision ports like I uses, you will cut the straight piece to 7″ and then glue the flares on. With flared ends, it’ll be about 13″ in total length. These are designed to be glued on with ABS plumbers glue. However, you can use superglue or any other type of glue. Just make sure their are no air leaks in the port. If you decide to use something else, like PVC pipe a good guesstimate would be about 10″ long, However, since I didn’t do that, I can’t say for sure. I would recommend flaring the ports if you decide to make your own.

      Speaker Cutouts and Attachment

      I did recess the woofer from on the outside of the box so that it would sit flush. This will be important to do if you decide to turn it into an end table. This allows you to put on around 6″ legs. Without this you will want to raise the legs up higher. Each woofer is placed 12″ from the bottom and 7 1/2″ from the side. The ports will be 5″ from the top or bottom and 15″ from the sides. You will need to line up the holes correctly so you can bolt the subwoofers together. You can use a centering punch, or what I will do is put the driver in the recess and drill one hole out. Attach a bolt then drill a second hole on the other side. Attach another bolt. The woofer should no longer be able to move, then you can drill all the other holes without worrying about it moving. Just make sure to drill them directly down and not at an angle.

      The easiest way to attach the woofers to the front baffle is to use bolts and nuts. I would recommend either locking nuts or double nuts to make sure they do not come loose. You can pick up bolts pretty cheap at your local hardware store. Places like Ace Hardware will sell them by the bolt, which is often times cheaper than buying them in bulk. I used 10-24 bolts that were 1 and 1/2″ long. I would not use anything shorter, and it might make it easier for some if they bought 2″ long screws. It would help, especially when starting the first nuts. You will need 16 of these bolts and nuts (32 nuts if you decide to double nut it).

      Bracing

      For the bracing I just use scarp from what I have cut that is the same size as the internal dimensions of the box. These strips I cut around 1.5″ wide using that 3/4″ scrap. I try to use 12 of these and make sure to glue them together. But you need to make sure you keep plenty of room to remove and install the subwoofers. Make sure they do not go over the ports or where the ports will be. I would wait to glue these in, until after the port were installed. For bracing you will want the following 1.5″ strips cut.

      • 4 – 28.5″ long
      • 4 – 22.5″ long
      • 4 – 16.5″ long

       

      Wiring

      Each pair of woofers will be wired parallel out of phase. This allows each woofer to move with each other. AKA when one is going in, the other is going out. On the inside of the box you will now have 4 wires that need to go to the amplifier. These will be wired in series to get to a 4 ohm load. The diagram below shows you how to do it, if you are unfamiliar with this terminology.

      I used a terminal cup to pass the wires from the inside of the box to the outside of the box. You can use anything you want including binding posts. One thing to think about though, is making sure your wires will be close to your terminal cup. So when placing the woofers and screwing them down, pay attention to where you’ll be attaching those wires on the woofers.

      Basic Assembly Directions

      There really is no right or wrong way to do this, but here is what I find the easiest. I glue all the sides on accept the baffle opposite of the woofers (I’ll refer to this as the rear baffle). I’ll then paint the front baffle where the woofers will be going. Once that is dry I will attach the ports. I’ll also mark the height of the subwoofer on the inside of the box. I want to move on to bracing. With bracing there are a few things to keep in mind. You want to leave room for you to be able to remove the subwoofers if you ever need to. So you do not want your bracing in a way that will impede that. You’ll want it outside too woofers or at least give you enough room you can remove it if you need to.

      I typically glue in around 12 braces. Two going to each side. Glue these to each panel of the box and to each other. This will help the sides flexing and resonating. Keep in mind, you will not glue 4 of the braces to the rear baffle, since it still is not installed. Do not install these over the ports or in the way of your amplifier or subwoofers.

      Once that is finished, I would install the drivers, make sure these are tight and secure. you can now wire these and install the terminal cups. Once that is complete you can glue on the rear baffle. I would glue this facing down, that way no glue will drip on to your woofers, ports or terminal cups. Once that is dry do your finish work and hook it up to the amplifier.


    • #12716
      blehaa
      Participant

      Nice build. I think I want to build these. This will be my first speaker build, and seems pretty straight forward. Just wanted to confirm, (excuse my lack of knowledge) I will go from the positive side amp to positive speaker 1 to negative speaker 2 to positive speaker 2 to negative speaker 1 to positive speaker 3 to negative speaker 4 to positive speaker 4 to negative speaker 3 to negative side of amp. That’s how I’m understanding the diagram you posted, just never done a speaker, nor any knowledge about parallel out of phase. 

      thanks for the help. 

    • #12717
      tvor-ceasar
      Moderator

      @blehaa

      Yes, that is exactly correct. If it makes it any easier to visualize, twist speakers 2 & 4 so they face speakers 1 & 3 respectively, and notice the wires will “X” over to the correct terminals and you can see why they need to be out of phase. 


    • #12718
      123toid
      Keymaster

      @blehaa

      I’m having a hard time visualizing what it is that you’re saying. But I trust true voice of reason. If you do decide to go forward with it, just know that we’re here to help you along the way. So when it gets to the wiring phase, you can easily just take some pictures and we’ll double check and make sure that it is hooked up properly.


    • #12719
      tvor-ceasar
      Moderator

      I’ve got a long work day ahead, but I should have time in the afternoon to hopefully throw together a graphic that better illustrates exactly what should be done.

      The diagram 123Toid supplied is 100% correct. I see where your possible confusion could be, since the drivers are in the same orientation, not facing each other and the connection plates are inverted on #’s 2 & 4. That was done for ease of diagramming.

      I’ll see what I can do in a few hours from now.


    • #12720
      blehaa
      Participant

      @tvor-ceasar

       

      THANK YOU A TON. I was also wondering about the Phase on the AMP itself, do I put the switch to REV or Nor (I’m assuming Reversed or Normal). I Just submitting my order for everything, $285.85 pre tax. 

    • #12725
      tvor-ceasar
      Moderator

      You are quite welcome. Always willing to help if I can.

      The Rev/Nor switch does sound like a phase switch. These are normally used if, when sitting at your listening position, it seems that the bass just isn’t working. Most times that means the bass waves from the sub are out of phase with the main speakers, creating some sort of null at that point. If you change the switch it puts the sub up to 180 degrees out of phase, and you should notice a difference, one way or another.


    • #12726
      ttan98
      Member

      Thanks for your DIY a few questions, please.

      I just want to clarify your wiring and installation of the drivers of your subwoofer by showing a diagram attached.

       this image shows only 2 drivers, they other 2 drivers are identically mounted behind these 2 speakers.
      Questions please refer to image:

      1. these 2 drivers are wired out of phase in parallel.

      2. the other 2 drivers also wired out of phase in parallel.

      3. (1) and (2) are then wired in series.

      if your installation is different, pls supply an actual wiring diagram/image of your DIY

    • #12727
      123toid
      Keymaster

      @ttan98

       

      That is correct both pairs are out of phase in parallel. The wiring from the amplifier to the two pairs is in series. I’ll try to update it with a better picture sometime.


    • #12728
      123toid
      Keymaster

      @blehaa

      Sweet!  I can’t wait to see it!  It is going to be killer!  Just don’t start complaining when you neighbors call you up 🤣 

      As far as the switch, that is up to the room.  But typically that is left in normal.


    • #12732
      ttan98
      Member
      Posted by: @123toid

      @ttan98

       

      That is correct both pairs are out of phase in parallel. The wiring from the amplifier to the two pairs is in series. I’ll try to update it with a better picture sometime.

      Thanks. Like your DIY on Tangband W5-1138SMF, for a ported single you think the optimum size is 6l or 7litre? Somewhere in between is OK?

    • #12733
      123toid
      Keymaster

      @ttan98

      Thanks. That all depends on what you mean by optimum. But I usually like it closer to 10l for optimal low end. 


    • #12734
      ttan98
      Member
      Posted by: @123toid

      @ttan98

      Thanks. That all depends on what you mean by optimum. But I usually like it closer to 10l for optimal low end. 

      The subwoofer(vented) built by Paul is closer to 6l, you think is too small? Parts express recommends 0.26cu ft(equals to about 7.3 litres), you suggest closer to 10lit. to get closer to 35hz at -3dB?

    • #12735
      tvor-ceasar
      Moderator
      Posted by: @ttan98
       
      The subwoofer(vented) built by Paul is closer to 6l, you think is too small? Parts express recommends 0.26cu ft(equals to about 7.3 litres), you suggest closer to 10lit. to get closer to 35hz at -3dB?

      Well, running the standard calcs as provided for by Thiele-Small, you get a box of 9.34 L (0.33 Cu.Ft.) with a Fb and Fp of 36.7 Hz and a F3 of 32.4 Hz. (Optimum)

      Pump that to 10 L (0.355 Cu.Ft.) and you get a Fb and Fp of 35.6 Hz and a F3 of 31.1 Hz, albeit with a very minimal loss of 0.14 dB at Fb, basically unnoticeable.

      And that’s just pure box, not taking into account what the driver takes up, or even the port. So even if it is a 10 L box, it is probably closer to 9 L or so once the driver is installed and even less with the port.

      I can only surmise what Paul is thinking in his design choice, seeing as it’s a smaller driver and normally that size would be suited to a slightly higher Fb. (6 L = Fb 42, F3 40.5)
      Parts express uses BassBox6, of which I am not acquainted in any way, but it seems they have a “High Quality” option that tends to shy away from absolute bottom end. (0.26 Cu.Ft. = Fb 39.3, F3 36.4) And did you ever notice they don’t specify anything for the port even though it is listed as “Ported”?


    • #12736
      tvor-ceasar
      Moderator

      To help visualize what is going on with the wiring.
      This is how most programs would draw it out, but it’s not that helpful.

      This is what it would look like in real life and how the wires would connect.

      Now take note, even though you are reversing the wiring on one of the drivers so that as one moves forward, the complementary one moves backward, and vice-versa, they are still in Parallel. That make the two 4 ohm drivers equal to 2 ohms. Then you do the same with the second set and have another 2 ohm pair. Now these pairs get wired together in Series making the total circuit go back to 4 ohms. 

      Hope this clears things up.


    • #12739
      ttan98
      Member
      Posted by: @tvor-ceasar
      Posted by: @ttan98
       
      The subwoofer(vented) built by Paul is closer to 6l, you think is too small? Parts express recommends 0.26cu ft(equals to about 7.3 litres), you suggest closer to 10lit. to get closer to 35hz at -3dB?

      Well, running the standard calcs as provided for by Thiele-Small, you get a box of 9.34 L (0.33 Cu.Ft.) with a Fb and Fp of 36.7 Hz and a F3 of 32.4 Hz. (Optimum)

      Pump that to 10 L (0.355 Cu.Ft.) and you get a Fb and Fp of 35.6 Hz and a F3 of 31.1 Hz, albeit with a very minimal loss of 0.14 dB at Fb, basically unnoticeable.

      And that’s just pure box, not taking into account what the driver takes up, or even the port. So even if it is a 10 L box, it is probably closer to 9 L or so once the driver is installed and even less with the port.

      I can only surmise what Paul is thinking in his design choice, seeing as it’s a smaller driver and normally that size would be suited to a slightly higher Fb. (6 L = Fb 42, F3 40.5)
      Parts express uses BassBox6, of which I am not acquainted in any way, but it seems they have a “High Quality” option that tends to shy away from absolute bottom end. (0.26 Cu.Ft. = Fb 39.3, F3 36.4) And did you ever notice they don’t specify anything for the port even though it is listed as “Ported”?

      thanks for a detailed response.

    • #12740
      123toid
      Keymaster
    • #12741
      lionhrt9
      Member
      Posted by: @tvor-ceasar

      To help visualize what is going on with the wiring.
      This is how most programs would draw it out, but it’s not that helpful.

      This is what it would look like in real life and how the wires would connect.

      Now take note, even though you are reversing the wiring on one of the drivers so that as one moves forward, the complementary one moves backward, and vice-versa, they are still in Parallel. That make the two 4 ohm drivers equal to 2 ohms. Then you do the same with the second set and have another 2 ohm pair. Now these pairs get wired together in Series making the total circuit go back to 4 ohms. 

      Hope this clears things up.

      That’s awesome. This build is going to happen for me as well. I used to run isoberic in a car as a teenager. As soon as I saw toid YouTube vid I knew I was in. I’m taking the recommendation and flipping the box upside down for wife approved factor and adding an oak top. 

    • #12744
      blehaa
      Participant

      Thank you for all the help, while waiting for the delivery I spent some time in Aspire (CNC Program) and designed everything. My AMP cut out (PER Parts Express) should be 8.5 x 8.5. I don’t know how precise that is but I made mine 8.6 x 8.6 then creating a pocket out to 9 9/16 x 9 9/16 at .25 deep. This is centered, and was wondering if I could move it down  My Two speaker cutouts are 9 inches with a 1/4in pocket out to 10in. The terminal cup in 2.7in and will create the flange pocket when they come in for measurement purposes. Port holes are 3 inches, and will create the pocket once they come in because I cant find any documentation on the curve or flange. I also created 7 inch feet for the bottom. I will be using 3/4 inch birch plywood because that’s what I’ve got and I’m staining it to match the rest of my entertainment center.  

      Open to thoughts or comments. 

      Am I missing any thing? I’m able to attach dxf and eps files, just don’t know if that’s frowned upon of the exact rule. (I haven’t gone thru all of the welcome rules)

    • #12745
      123toid
      Keymaster

      @blehaa

      I don’t see anything you’re missing, also the files didn’t seem to attach. I also enlarge the cutout just a little.  If you move the amplifier down, just make sure it doesn’t get in the way of the binding posts.  It actually makes a lot of sense if you put it closer to the bottom of where the drivers are, it might make bracing it a little easier. 


    • #12750
      blehaa
      Participant

      @123toid

      Sorry about that, Ill try again. 



       

    • #12804
      123toid
      Keymaster
    • #12826
      lionhrt9
      Member

      Coffee table rendition. Subs and amp will be here Tuesday!  We used 3 sticks of 1×8 clear pine glued together for top. 


       

    • #12831
      blehaa
      Participant

      @lionhrt9

       

      Looks great, your beating me on my build, all my parts just came in, I waited to cut to make sure I had nice tight fits, 

      If any one wanting to build this and using exactly what was recommended Here are the exact sizes I came up with. 

      GRS 10SW-4 is 10.125 (10 1/8) inches Diameter with a .5 (1/2)inch flange with a .375 (3/8)inch thickness (if you want to pocket it.  Giving you an inner Diameter of 9.125 (9 1/8) inches

      Dayton Audio SPA250 9.875 (9 7/8) inches x 9.875 (9 7/8) inches Flange is .3125 (5/16 thick) inch If you want to pocket

      Precision Port 3 inch had on outside Diameter of 6.5 inches with a .625 (5/8) inch flange, witch would give me a 5.25 inner diameter due to the flange. Does this sound correct for a 3 inch port? I have DXF Files to share to verify. 

      All parts will be cut out with a CNC.  

       

       

    • #12833
      123toid
      Keymaster

      I am really getting excite to see all these finished!  You guys are killing it!


    • #12841
      lionhrt9
      Member

      Watch your bracing. Lol. Thank God I could still move them outta the way.


       Amp came in as well. 8.5 inch cut out was just enough. Gasket will be tight. Gluing rest of braces in tomorrow. Pocket drill for top attachment. I forgot to order the collars for the port tubes which are now back ordered till end of week.

       

    • #12843
      123toid
      Keymaster

      @lionhrt9

      Woah!  Cutting it close, eh?  lol. The bracing is by far the trickiest part of this build.  Glad you didn’t have to cut it out.  Of course, you can always cut one out if you need to, but who wants to do that?

       

      It is looking great so far!


    • #12846
      lionhrt9
      Member

      In hindsight I would move my lower braces up another inch or so and keep them off center like that just to be sure. Those subs are 5 inches deep with magnet. Also on the long side im only putting 2 staggered as that’s the most ridgid side and ive still gotta install some egg crate foam. It’s plenty stout already. Can’t freaking wait to at least get this powered up. Im thinking locating inside subs where I want them then marking and drilling bolt pattern, sticking bolts then threading on bottom subs onto bolt stems, that’s probably gonna be a 2 person job.

    • #12849
      lionhrt9
      Member

      Also another possible tip for future builders. Im thinking threaded inserts for the amp. I believe it will be the most logical access into the box as subs are bolted together. That being said I’ll bet those 3/4 inch wood screws will loosen after a couple times. So now I’m in between tee nuts or hurricane nuts with some glue. Also don’t wanna order something like that from PE as delivery will kill me. So maybe a trip to my smaller town hardware store is in order. Im leaning toward hurricane nuts. Any insight? 

    • #12850
      lionhrt9
      Member


    • #12896
      lionhrt9
      Member

      Getting ready for primer more sanding and hole filling. 2nd coat of general finishes arm r seal. Highly recommend this stuff, thanks nick. Attaching top with glue and pocket screws thru amp hole.

       

    • #12901
      123toid
      Keymaster

      @lionhrt9

      Looking great!  I can’t wait to see this finished!


    • #12926
      lionhrt9
      Member

      Im brain dead after today’s work. Posted in wrong spot. Sry bout that guy’s. 

       

      Tons of work today. 1st coat everything. 2nd coat once finally built. We hooked it up without securing the top and holy cow it scared the crap outta both of us when lfe kicked in during hill house storm scene. Unplugged and set top piece in glue and finally got 6 screws in it. Im spent.



    • #12928
      123toid
      Keymaster

      @lionhrt9

      Ha!  That is hilarious! Note to self, don’t play the subwoofer without the top on. 😆 

      I am really digging your setup.  That is looking really sweet!  I can’t wait for you to have it hooked up. Next time, I should have you build mine, so I don’t have to 😜 

      Really fine craftsmanship.  

       

      Wait, did I misread that?  I thought it said without securing the top on, but them I re-read it….oh well. Not like it is on the internet for everyone to see. 


    • #12930
      lionhrt9
      Member

      @123toid

      Yea. I tried to set a heavy plant on top….. that didn’t work. After glued and screwed I played bass sweep this morning. Holy s^$!!. Never felt 10hz from a sub ever outside of transducers in my couch. Then 20hz revealed a ton of rattles in our fireplace! But my favorite and it’s sweet spot is 25hz! House shaking! Im absolutley blowed away man! It’s super clean as well. I’m taking it downstairs to theater today and 1st play is going to be tron!

       It puts my 15 to shame. Great use of 250 watts! A non audio guy at work told me 250 was not going to be anywhere enough for 4 10s. He couldn’t have been more wrong. Without any calibration I just unplugged the 15 at 50 percent gain and the iso100 box is set below 50 percent gain so it’s super efficient! 

      I wanted a 10 foot cabinet but it looks good even at 5 feet! Lol

      I got the perfect video! Wait to the end! 

    • #12931
      lionhrt9
      Member

      Here’s the video

    • #12932
      robbiedh02
      Participant

      @lionhrt9 Yoi did a great job, looks really nice!

    • #12933
      123toid
      Keymaster

      @lionhrt9

      Hahaha! That had me cracking up this morning! Great job on the finish, it looks fantastic! Sounds like you’re enjoying that low low bass 😁 


    • #12942
      123toid
      Keymaster

      @lionhrt9

      Alright, I have to ask. What 15 did you have?  

      I’m glad you are liking it.  I think it is unbelievable performance for the price. Sounds like you feel the same. 


    • #12947
      lionhrt9
      Member
      Posted by: @123toid

      @lionhrt9

      Alright, I have to ask. What 15 did you have?  

      I’m glad you are liking it.  I think it is unbelievable performance for the price. Sounds like you feel the same. 

      I still have it in livingroom setup. It’s the parts express sub 1500. I mean for the price it sounds alright. Im actually considering pulling the amp and looking at a passive resonator sub. She’s not going for large sub boxes up here. To be honest I’m really digging the iso100 responses at lower hz. And I can tell it’s getting better after alittle break in period. It felt a bit punchy at first.  I feel like I’ve been missing so much from our experience and that includes 2 transducers we have installed in livingroom. 

    • #12957
      lionhrt9
      Member

       

      Finally got it moved down to theater room. Ran bass sweep from 0 to 60hz and it shook the projector! Ive never seen that! I mean it’s probably something im gonna have to look into isolating at some point but it added kind of a special effect to the YouTube video. Lol. I ran audessey thru denon and calibrated iso100 and klipsch 10 that’s sitting up front by screen. Im still thinking about getting dsp lf for tuning it.

       

       

    • #12960
      123toid
      Keymaster

      @lionhrt9

      It really is an awesome experience getting that crazy low end bass extension, isn’t it? I absolutely love that!  I never even thought about your projector shaking.  That is crazy! Is it hung from the ceiling? 

      I love the DSP-LF for the price.  It just does it’s job.  It is really nice if you have an iPhone, since it auto calibrates.  I still for the life of me can’t understand why they have 3.5mm jacks instead of RCA’s.  Seriously, who is going to use 3.5mm jacks? anyway, not sure if they changed the cabling that came with it, but I used these to convert the 3.5mm to rca


    • #12965
      lionhrt9
      Member
      Posted by: @123toid

      @lionhrt9

      It really is an awesome experience getting that crazy low end bass extension, isn’t it? I absolutely love that!  I never even thought about your projector shaking.  That is crazy! Is it hung from the ceiling? 

      I love the DSP-LF for the price.  It just does it’s job.  It is really nice if you have an iPhone, since it auto calibrates.  I still for the life of me can’t understand why they have 3.5mm jacks instead of RCA’s.  Seriously, who is going to use 3.5mm jacks? anyway, not sure if they changed the cabling that came with it, but I used these to convert the 3.5mm to rca

      Yea, low bass! I want to say that most are missing it until you hit this level or experience it in a show or something. To be honest I doubted I would ever be in a place where I could experience that at my house. We do not get this audio experience in theaters at all and that includes IMAX. I mean there’s a ton of money in audio right? To get something that performs like this and affordable to guys like me via DIY opens up all kinds of possibilities and you know its solid and the inter workings of it because you built it. I’ve been inside my lower end klipsch speakers, they do their job but you can tell they need to make money.  I’m obviously totally hooked at this point and so glad I came across these pages to get me started.  As you know, its some work and time but the payoff is there no doubt 100 percent.  Now ive got some of the tools and connectors and what not, I’m pretty set up and comfortable enough to proceed with some more builds!  Theres no doubt I enjoy hifi audio but the price points kinda knock me out of most purchase possibilities.  Some patience and work and incredible knowledge here and elsewhere online and most anyone could be in business!

      2 things you already picked up on and I also have issues with the DSP-LF. The apple handcuffs (im a droid/PC guy) and the tiny jacks.  I get the consistent mic thing for apple but the jacks just makes me scratch my head.  So,….. my work issued me an ipad but they’ve locked it down which is understandable.  Im trying to describe to our IT department why I’d like to use my company ipad to install an app temporarily. They are so confused on why someone would need an ipad to calibrate a subwoofer. LMAO. 

      As far as projector, yes i personally installed it on our ceiling into floor joists!!! and I’m as shocked as my wife when testing with bass sweeps, I mean theres other stuff hanging on walls thats rattling to but the energy it takes to transfer up the wall and into the ceiling down to project!

      It maybe just perception or location but it seems the 25 and 30hz decibels are louder than 35 to 50 range. This is why i want to get that DSP, kinda like taking control of this project I’ve got sometime into. Also with the apple vs droid thing, I guess I could just bypass the whole auto calibrate thing till I get access to an apple product, covid kinda put the damper on anyone coming by to use their iphone for now.

      Sorry for the ramble, got carried away. 

    • #12992
      123toid
      Keymaster

      @lionhrt9

      Yeah I really like the DSP LF for the price. It does help you get rid of those room modes that can play with your bass response. That’s a typical range for you to get a boost in the bass region. 


    • #12993
      marcopolo
      Member

      Hi guys.  I just found toids YouTube channel and joined here because of this iso build.  I’m clueless about Box design and tuning it so sorry if this a dumbass question but: could a person build it so the drivers are completely enclosed within the box volume and you only have the ports on the outside?  Also, if i changed the box shape(even with same volume), I’ll have to change the port config for a correct tune as well i guess?

      Thanks

    • #12994
      123toid
      Keymaster

      @marcopolo

      That’s actually not a dumb question at all. You can rearrange the shape to pretty much anything you want as long as you keep the internal volume the same. That will make sure that the ports and everything are the right size. Otherwise you’re going to need to recalculate everything. As far as having all the speakers inside the box, no. However you can attach a small sealed box to the front. And have those woofers facing out. The other woofers will be directly behind those, hidden in the box. This is another way to do an isobaric configuration, but it will have an effect on the final response. Unfortunately since I didn’t test it come I can’t tell you what it will be. 


    • #13016
      marcopolo
      Member

      @123toid ok understand.  I guess it could be designed into a band pass design but that would basically be a whole a new design.  I’m trying to figure out the best way to get a subwoofer in my attic that will drive bass into my living room with the smallest grill/opening possible. 

      I had a proper 10 inch ceiling subwoofer from home audio direct in my previous house but it was sadly anaemic 🤣.  My Tektons go down to 37 but i want add a bit more punch.  I don’t need 20hz, but would like to down below 30 with flat response so if you have a build you can link me to or any advice I’m all ears.  

      Your videos are really great by the way.  A breath of fresh air in the YouTube audio category. 

    • #13629
      ninjedi9000
      Member

      Hey guys planning on making this box any new tips from anyone who has done it? Also can i do it with 1 terminal plate in the middle by running both inside subs then out to go thru the outside subs? they will still be in series.

    • #13631
      123toid
      Keymaster

      @ninjedi9000 

      You could use a dual terminal cup, just be sure to remove the jumper. 

      I don’t have any real tips, but would be happy to help if you need it along the way. 


    • #13634
      tvor-ceasar
      Moderator

      Check page 2 of this thread for an explanation and diagram of wiring. Should clear up any questions you may have on that.


    • #13639
      padenormous
      Member

      Hey everyone. Super excited to be apart of this community. I’m wanting to follow these steps exactly, except I have to use the 12” version of the subs. 

      My question, does anyone have a formula or rule of thumb or something so I know what dimensions to make the box for these subs? 

    • #13640
      tvor-ceasar
      Moderator

      The beauty of this design is that you can use the T-S parameters for  the single driver to model the whole thing. The whole thing hinges on the fact that the only parameters that really change is just one: the Vas. When you put the drivers face to face in push-pull, the Vas is cut in half. When you put 2 drivers “side by side”, you double the Vas. So in essence, what you have done is made two (2) 1/2 Vas,.which puts it back to the original Vas. And that’s how you can model it using just the single driver. 

      If you would post the model #, we can do a quick rundown. Of course, if you download WinISD, you can check out the modeling.


    • #13641
      padenormous
      Member

      @tvor-ceasar 

      Thanks for the reply! That makes a whole lot of sense. So really I can just model a side by side configuration and get the same measurement I need for my isomeric setup. 

      https://www.parts-express.com/GRS-12SW-4-12-Poly-Cone-Subwoofer-4-Ohm-292-484

    • #13642
      123toid
      Keymaster

      @padenormous 
      There was a reason I didn’t go with the 12″, but for the life of me I can’t remember off hand.  I am going to check out the new HE version as well.  That might be a really cool build.


    • #13643
      padenormous
      Member

      @123toid 

      If the GRS 10SW weren’t on back order until the end of September, I would have gone with those. But I can’t count on my motivation lasting another 3 months before even starting this build.

    • #13644
      123toid
      Keymaster

      @padenormous 

      the HE version of this sub has a lot of potential.  It can do 4 of them in an isobaric with an f3 of 18.8hz and can supposedly can take up to 2000w (I’m not sure I believe that).  However, even with a mere 250w it hits almost 106dB.  The best part is it only needs to be about 4 cubic feet.  If I were to do a do a build with the 12″, I would do the HE version

       



    • #13645
      padenormous
      Member

      @123toid 

      Granted that the HE version of the sub is better, seemingly a lot better, if you compare the 12″ subs I linked (and already bought) to your original 10″ sub configuration, can I expect the same, if not a little better, performance as you demonstrated?

    • #13646
      tvor-ceasar
      Moderator

      IIRC, you used the 10″ for several reasons, the 2 biggest were:

      Price

      Box size

      You modeled about 24.6Hz Fb and 17Hz F3 with a 6 Cu.Ft. box, and the power and SPL were pretty good too.

      If you were to go with the 12SW, you can go with a 7 or 8 Cu.Ft. box with similar size ports and you’d hit 23/20 Fb/F3 with the 7, and 22/18.5 Fb/F3 with the 8. The sensitivity would be about the same. I haven’t checked the ports for noise, so that’s something for WinISD to do. 


    • #13647
      tvor-ceasar
      Moderator

      @123toid 

      Just a quick question – when you do your “Quick calcs” such as above, what’s the minimum driver info you put into WinISD for those “quickies”?


    • #13648
      123toid
      Keymaster

      @tvor-ceasar 

      Lol, all of them. I just haven’t gone through all of the graphs. I looked at the basic ones. But I need to go more in depth for port size, velocity, etc. 


    • #13649
      tvor-ceasar
      Moderator

      @123toid I understand. What I’m looking at is how fast you had the rough check of that driver in WinISD. You must have them already in the driver database, since I know how long it takes me to put all the T-S parameters in by hand. It sure isn’t as fast as you! 🤣 


    • #13650
      123toid
      Keymaster

      @tvor-ceasar 

      I appreciate that, but I did actually just put all the parameters in by hand 🤣  What can I say, I have no life 🤣 😀 🤣 


    • #13651
      tvor-ceasar
      Moderator

      @123toid 🤣 🤣 🤣 That’s what I call practice!


    • #13652
      padenormous
      Member

      I’ve got another question. I’m making peace with my sub-par (no pun intended) purchase of woofers. Now, I’ve got a 4 channel 800w RMS amp that I intend to use to drive my speakers (8 40w 4ohm thrusters) which will take up channels 1 and 2. I’m going to use channels 3 and 4 bridged to power this subwoofer. Someone tell me why this is not possible?

      It seems to me, I’m going to max out these speakers at ~320W and have a remaining ~380w left over for this sub. Am I simply an invalid or am I thinking about this correctly?

    • #13653
      tvor-ceasar
      Moderator

      It all depends on the amp. Generally, when you have a 4 channel amp like that, it is 4 x 200 watts at some nominal impedance, probably 4 ohms.

      In your case, you describe having 2 channels driving 4 each Thruster drivers, parallel/series to 4 ohms, at a total of 160 watts each side. Leaves you 40 watts/channel headroom. 

      The bridged section should deliver 400 watts (minimum) into it’s rated impedance, possibly up to 800 watts. If your sub matches that impedance, you can get that full rating, whatever it is, up to the sub’s rating.

      Like I said, it depends on how the amp was designed and how the manufacturer rates it.


    • #13654
      123toid
      Keymaster

      @padenormous 

      Honestly after giving it some thought, I just realized the 12dw-4he was going to cost around $160 for four of them.  At that price point, I would go with the the MX15 for only $12 more.  The regular 12″ don’t model well IMO.  If you really want to build this, I would just order them now, so you get your name in line.  Otherwise, they could sell out when they get back in stock.  Ask me how I know 😉 


    • #13660
      padenormous
      Member

      Hey guys, we’ve got a work in progress with the box. It’s going to be 10sqft volume for the 4 12″ subs. I have a couple of questions as I make some headway here.
      1. How big do I make the hole for the 3″ flaired ports?
      2. Are you supposed to put some materials inside the enclosure for sound dampening/removing standing waves?

      Thanks guys!

    • #13663
      123toid
      Keymaster
    • #13669
      padenormous
      Member

      @123toid
      GRS 12SW-4 12″

       

    • #13670
      padenormous
      Member

      Here’s the work in progress. Made out of a 40 year old office desk. Heavy as hell, but should be solid as all-get-out.

    • #13672
      padenormous
      Member

      So I did some more looking and found that for the 3″ flared port, I need a 5.25″ cutout. The reason I’m checking this instead of just buying the flared port and measuring myself, is I designed my own port and 3D printed it. I’m about half way done and I need to print the second port as well. 

      Here’s a question. I’ve calculated it out and the port length should be 7.33″. If my flare sections are 3″ each, does that mean I just need 1.33″ of tube between them?

      Here’s what I’ve got so far.

       

    • #13674
      123toid
      Keymaster

      @padenormous 

      I’m not sure I understand the question.  But typically the flare you can only count about half of it. So if the flare is 3 inches, it’ll only count about 1.5″ of actual port length.  So you would need and additional, almost 6 inches to equal your target.


    • #13675
      padenormous
      Member

      @123toid 
      Do you do both ends of each port flared? So would that mean (1.5″ x 2) + 4.33″ of tube = 7.33″? 

      Also, I have a more general question about tuning the sub. Are the box size and port dimensions the only variables I’m changing to tune this thing? Or does tuning also mean actually dialing in the frequency and crossover/etc on the amp?

      Thanks for all your help guys

    • #13677
      123toid
      Keymaster

      @padenormous 

      That would be the best for cutting down port noise.  And yes, that math would seem to be correct. 

      You should check your tuning frequency before gluing the port together.  You can do this easily with dats.  If you do not have dats, then you can just play test tones through the subwoofer and when the cone is barely moving, you have hit your tuning frequency.  Then adjust your port size from there. 


    • #14606
      neilyboy
      Member

       /edit… I went ahead and modeled all of this.. I will give it a go at printing tonight. Will share these up if anyone is interested and it works. May have to check that the length is correct of course. I have it so end to end it is 13″




      @padenormous 

       

      /old post….

      Did you happen to finalize your stl files for this project? I am thinking about attempting this project. I (like you) see no reason to purchase these when they could very easily be 3d printed! I would love any advice you can give me as far as design went or if you are open to sharing your stl. If not I can fumble my way through fusion360 enough to accomplish this (i hope).

      Thanks a ton in advance!

      Neil

    • #14694
      neilyboy
      Member

      Is anyone able to help me understand what I am doing wrong? I have this all hooked up (and unfortunately sealed). I am able to get it to run for about 5 minutes (just over one song) before it starts to pop and over-heats (heat-sync) on the back is hot to touch and it (im guessing) goes into some thermal protection. I must not have this wired properly but I followed the diagram on the first page exactly. Please see picture that I took before putting top on for reference.

      Thanks so much in advance!!

       

    • #14696
      123toid
      Keymaster

      @neilyboy I don’t have time to double check it right now.  But measure your impedance where they go into the amplifier.  If that is anything other than 4ohm, report what it is. 


    • #14701
      neilyboy
      Member

      @123toid I’ll get it first thing in the morning.  I unfortunately sealed everything up so I’ll have to either destroy what I have or find a strategic place to perform the operation 😆.  I’ll get some multimeter numbers first thing in the morning!  Wifey wanted to put the tree up tonight so I was unable to get some time to myself…

      Neil

    • #14702
      tvor-ceasar
      Moderator

      You should be able to remove the amp, remove one of the leads and check across them.

      Being as Re is listed at 3.96 ohms, and the wiring is meant to keep it at 4 ohm impedance, you should measure somewhere around that number. Anything lower means you have a wiring issue.


    • #14703
      neilyboy
      Member

      I’ll first test both s2 and s4 from outside the box .. I unfortunately soldered and closed everything up….. if both s2 and s4 test at 3.7-4ohm I’ll figure out the best way to open up the box so I can reseal it later. First thing in the morning I’ll get some numbers on here.  Thanks for all the help.  I have the stls to post if anyone wants them as well.  They printed beautifully

    • #14707
      neilyboy
      Member

      It hangs exactly at 4.2-4.3 ohms when testing the leads that head out to the amp…

       

      Had to cut a monster hole out of the top to verify but I’m not understanding why this thing over-heats and turns itself off its all brand new components and I soldered everything direct..

       

      Any other ideas or things to check? 

    • #14708
      123toid
      Keymaster

      @neilyboy 

      If that’s the case, then there’s a problem with the amplifier. Or your wiring is shorting out. Ie your positive and negative or touching somewhere. From the pictures I don’t see that being an issue. In this case, I think you might have a problem with your amplifier. I would try hooking it up to just one of the subwoofers and see if it does the same thing. 

      You could also double check your home theater receiver and make sure that it’s not over driving them.


    • #14710
      neilyboy
      Member

      Good idea on driving one I’ll try that for awhile.  Will it hurt a driver being mounted to the face of it (I’d hate to try pulling subs back off) while only one is pumping? I have an open ticket with parts express so we will see where that goes…. bummer thanks for the help thus far! I have built 3d printers and cnc machines from scratch so figured this couldn’t be that difficult lol..

       

      Neil

    • #22860
      nickd
      Participant

      Im thinking of doing the end table version of this. Seems like the Dayton spa250 amp is recommended. Being an end table, and for better WAF, I’d like to skip a plate amp, and maybe even paint the horns to match whatever color is the end table. What options are there for external amp 100w-250w, preferably under $200? 🙂

      Perhaps the AIYIMA 200W Subwoofer Amplifier Mono Amplifier Class D Amp for $72?

    • #22863
      123toid
      Keymaster

      I wouldn’t use that one. It doesn’t have a good enough power supply or caps to really be demanding enough for a subwoofer. If you can’t hide the plate amplifier on a certain side then I would go with the SA230. It is a little more than $200, but if you use the coupon code CJ2FIVE it should take off $25 on any order over $300. That would get you close to the $200 (about $215, I believe).

      Another option is still use the spa250, but build a small enclosure for it. You can put that anywhere and just run speaker wire from that location to the end table. It would basically end up being the same thing as an external amplifier. The spa250 is completely sealed, so it really doesn’t matter where it goes.


    • #22881
      nickd
      Participant

      That’s a good point maybe I can put the spa250 closest to the couch on the long side of the end table, to hide it!! Then the ports will still be on the short side of the end table

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