My first sub-beginner DIY - Page 5 - Home Theater Forum and Systems -

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post #41 of 48 Old 10-28-10, 09:23 AM
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Re: My first sub-beginner DIY

In your modeling you have an input power of 1000 watts. You should have a HPF at 16 hz. The slot port shouldn't be narrower then 2" so 2" x 14" x 33" would be my choice.
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post #42 of 48 Old 10-28-10, 08:33 PM Thread Starter
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Re: My first sub-beginner DIY

ok thanks mikep Gonna draw it up one last time for final confirmation but i feel like i have the design done.

As for the high pass filter....why 16? All i understand really is HPF prevent anything lower than what it is set (ie at 16 nothing lower than 16 will come through) . It seems like you could do this cause of cone excursion max prevention. But iin my model it shows cone excursion at ~13hz. Im just curious how come you say 16hz is all (more just an understanding thing than anything else)

Last try for this thing i hope. Im going to add in the bracing or sorts just to give an idea as well, not sure on exact design but gives an idea.

Ok got annoyed ta my google sketchup abilities but got it for the most part. Got the vent and bracing in so should give a good idea. Might also do a fore/aft bracing but havent decided on that yet. Amp can go anywhere if i go with plate amp.Also got a "rough" tempest x drive in to make sure the bracing had clearance.

Again INTERNAL dimensions are 20x31x20
Tuned to 18hz @ 1000W
Port= 2"x14"x~33.5"
Cubic feet wise approx 6.2 cubic feet from what i figured. im comfortable where it is box size wise though. with the added plate amp its probably right around 6.0 cubic feet.

Here it is, notice any FINAL thing wrong? I sure hope not cause i plan to start building tomorrow

Thanks for all the help guys. hopefully i can get the "looks good" and can start a build thread!
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post #43 of 48 Old 10-28-10, 09:17 PM
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Re: My first sub-beginner DIY

Your box design looks sound. The internal dimensions seem close to your calculated numbers, depending on final bracing. The port dimension is sufficient to keep air velocity reasonable and the resonant frequency out of the operating range. It looks as though you're using a double MDF thickness for the baffle which is a good practice. Most recommend at least 3" of clearance below the down-firing woofer, so keep that in mind when designing feet for the subwoofer.

Regarding the HPF, the purpose is to prevent over excursion of the driver near the tuning frequency. You can see this in WinISD by keeping the cone excursion graph below the red line for the driver at all frequencies. If the only crossing is sub-15Hz, this is generally considered OK due to the fact this should only occur during full power delivery from your amp (not typical) combined with actual significant content material at that frequency (rare).

Also, if you are considering a 1000W plate amp, the only two I'm aware of are the Dayton SPA1000 and the ED LT/1300. The Dayton has a single band of parametric EQ only down to 18Hz, so you won't be able to do a 16Hz HPF with it. The ED as far as I know doesn't have a HPF filter function, so again no 16Hz HPF built-in. In both cases you would need an external HPF function. As such, you may wish to consider an external 1000W amp and dedicated HPF/EQ device.

Good luck and have fun,


Last edited by dboff01; 10-29-10 at 08:11 AM.
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post #44 of 48 Old 10-28-10, 09:33 PM Thread Starter
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Re: My first sub-beginner DIY

Thanks i was planning on 3-4" clearance on the bottom. Depends what i decide to do/buy for feet but minimum 3". I havent finalized what material i will use or how the finished product will look though. internally though those are the dimensions and the bracing and port will be 1/2" mdf. Outside i've got plenty of ideas in my head ranging from oak to just 3/4mdf to a combo of the both. Just have to hit the hardware store and see what i actually like.

Ahhh that explains why you need a HPF so thank you. Looks like 16 is the magic number as MikeP already stated.

I thought i had a good line on the ED LT/1300 but if it doesnt have the HPF might just go with the external since i'd need an external filter device anyways. Bit more added cost but o well its worth it Guess one nicer thing is there wont be the plate on the back of the sub. So i can hid the wires a bit more which the gf will appreciate.

Thanks again guys and do expect a build thread in a couple of weeks!
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post #45 of 48 Old 10-29-10, 12:25 AM
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Re: My first sub-beginner DIY

I recommend the EQ.2 for your hpf duties. I imported one into the UK and its great. 2 bands of EQ too which comes in handy especially if you don't need much EQing. Its very accurate too. I have 3 tunes on my subs and one off them is 17.5hz and even up to -20db on the Onkyo, I still have it on minimum and don't see any where near max excursion on most stuff so at normal levels you probably won't need to set it as your winisd plot says. Obviously if you play music or movies which have alot off sub 20hz content you may find you want to turn it up a bit.

The ED plate amp is expensive in relation to the behringer pro amps but atleast it doesn't have a noisy fan which if you don't modify will annoy you.

Looking forward to the build matey.


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post #46 of 48 Old 10-29-10, 07:14 AM Thread Starter
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Re: My first sub-beginner DIY

Will keep that in mind when i look for a HPF. Probably just go super simple as i odnt plan on adjusting it very much after inital setup/testing/playing with.

The only reason i considered the ED plate was i had a good deal on a used one lined up. For about the same price as a new ep2500. But if it still needs a HPF ill just save more money and get the ep2500 or similar.

As for power i guess im just stupid when it comes to it. So let me just ask. Basically theres the ep1500 or ep2500.

The ep1500 provides
2 x 700 Watts into 2 Ohms; 1,400 Watts into 4 Ohms bridged operation

The ep2500
2 x 1,200 Watts into 2 Ohms; 2,400 Watts into 4 Ohms bridged operation

So if i understand right, the ep2500 all i would need is a single channel and i could get my 1k W power. However i could go with the ep1500 and use the bridged operation to get the 1k W too. So really either would work with the real cavat being the ep2500 would still offer 1 free channel for expansion/whatever whereas the ep1500 would be "maxed" so to speak channel wise.
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post #47 of 48 Old 10-30-10, 09:50 AM
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Re: My first sub-beginner DIY

I would put 3 braces in that box to keep unbraced wall spaces to less than 1 square foot

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post #48 of 48 Old 11-16-10, 07:43 AM
Join Date: Nov 2010
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Re: My first sub-beginner DIY

I love this design, (, 147 litre Slot Ported Cab for 15" Subwoofer (21hz)
How can I get 2D cutting sheet?
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