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Discussion Starter #1
Hello everybody,

I have currently two infinity 1260w sealed subwoofers. They play very nice but I want more bass:D


Because the infinity are very cheap here I bought two more. I want to build a ported subwoofer with two drivers in one box.

The design I have so far is a 170liter box tuned at 21hz.
Air speed limited to 16 m/s.
Port length will be 850mm.

Here are some winisd pictures.




Box will be made from 22mm (0.86 inch) mdf and with a lot of bracing.
The design has thee ports.
I have read some stuff over that the ports acts like one port so i shortened the port with 10%.



Does anybody have some tips, criticism, complaints etc. before starting with the build?
Thanks in advance!!!:cool:
 

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Is that 170 liters net? (ie, The final box will be larger to account for volume taken up by the port, driver and bracing?)
If so, you will only be giving up a couple db in the 20 Hz range compared to a larger box so not a huge deal. If your design is 170 liters total then I think you will be making a noticeable compromise.

I built four separate ported 1260W subs, each at 130 liters turned to 18 Hz. Unfortunately I haven't been able to find actual frequency measurements for this design, only modelling graphs, but the low end sure sounds sweet to me.

If you built that sealed sub in the picture then I'm sure the ported boxes will turn out great. Really nice job with the recessed driver and professional looking finish.
 

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Discussion Starter #4
Thanks for the reply's!:)
Is that 170 liters net? (ie, The final box will be larger to account for volume taken up by the port, driver and bracing?)
If so, you will only be giving up a couple db in the 20 Hz range compared to a larger box so not a huge deal. If your design is 170 liters total then I think you will be making a noticeable compromise.

I built four separate ported 1260W subs, each at 130 liters turned to 18 Hz. Unfortunately I haven't been able to find actual frequency measurements for this design, only modelling graphs, but the low end sure sounds sweet to me.

If you built that sealed sub in the picture then I'm sure the ported boxes will turn out great. Really nice job with the recessed driver and professional looking finish.
Thank you for the compliment, your subs turned out great too!
The 170 liter is net. My room is not very big so I am limited with the size of the box. The design what I have now is about the max.

You can model the subs up to about 16-17mm instead of stopping at the 13mm line.

You may want to tune a little lower with a bit bigger box, see what a 100cm port looks like with a 400 liter box size.
I didn't know that the excursion can be a little bit higher, thanks!
I have played with winisd with a bigger box but I don't have the space here. :(
 

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Is this in addition to the sealed subs, or a replacement? A little bigger box would be a big advantage, but I understand your space limitations.

If in addition to the sealed, you're almost better off with a single 1260 in that enclosure. You could tune it to 16Hz and you will be at about the same SPL at 20Hz as the dual.. and you will have good extension to 16Hz. I'm seeing a flat 106dB from 16Hz to 30Hz and only down 2dB from 80Hz.

Could tune it a little higher and actually have more SPL from a single in the ~20Hz region.

Tim
 

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Is this in addition to the sealed subs, or a replacement? A little bigger box would be a big advantage, but I understand your space limitations.

If in addition to the sealed, you're almost better off with a single 1260 in that enclosure. You could tune it to 16Hz and you will be at about the same SPL at 20Hz as the dual.. and you will have good extension to 16Hz. I'm seeing a flat 106dB from 16Hz to 30Hz and only down 2dB from 80Hz.

Could tune it a little higher and actually have more SPL from a single in the ~20Hz region.

Tim
Am I missing something? The green curve is 2X1260W in 170 liters tuned to 21Hz and the pink line is 1X1260W in 170 liters tuned to 16Hz. Even if you keep amplifier power the same the dual cabinet has an advantage at all frequencies above 20Hz.

 

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Discussion Starter #8
Is this in addition to the sealed subs, or a replacement? A little bigger box would be a big advantage, but I understand your space limitations.

If in addition to the sealed, you're almost better off with a single 1260 in that enclosure. You could tune it to 16Hz and you will be at about the same SPL at 20Hz as the dual.. and you will have good extension to 16Hz. I'm seeing a flat 106dB from 16Hz to 30Hz and only down 2dB from 80Hz.

Could tune it a little higher and actually have more SPL from a single in the ~20Hz region.

Tim
Thanks for your response.
It is an addition to the sealed subwoofers.
I've simulate your model and a few more but two subwoofers in the 170 liter enclosure will give me more SPL when I tune the box lower (16 or 18 hz).
It's off course not as efficient when you look at the watts but I have already a inuke 3000 dsp so that's no problem.:D

 

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Am I missing something?
No, I am. I was referencing the graph in the OP. When I model it myself I get something a little more similar to you:



In a combo scenario it's rolling off where you need it, but SPL is SPL. When I mixed sealed and horns I had to HPF/LPF so they both weren't covering the same frequencies. Don't recall the actual pass frequencies.

Also depends how deep you want to dig :D

Thanks for pointing out the error!

Tim
 

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Thanks for your response.
It is an addition to the sealed subwoofers.
I've simulate your model and a few more but two subwoofers in the 170 liter enclosure will give me more SPL when I tune the box lower (16 or 18 hz).
It's off course not as efficient when you look at the watts but I have already a inuke 3000 dsp so that's no problem.:D
Yeah, sorry man. I'm a little rusty; I should have modeled the dual.

The single in the same enclosure is flat at 106dB but the dual definitely has the SPL advantage.


edit: attached my T/S specs.. not sure why our models aren't matching better

Tim
 

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Discussion Starter #11 (Edited)
Thanks for the replies!


Yeah, sorry man. I'm a little rusty; I should have modeled the dual.

The single in the same enclosure is flat at 106dB but the dual definitely has the SPL advantage.


edit: attached my T/S specs.. not sure why our models aren't matching better

Tim
No problem, thanks for the thinking.
My T/S specs are on some points a little bit different I see.
I'm gonna check mine if the match with the data from infinity.

Maybe i tune the box a little bit lower, I'm gonna think about it.
I buy the wood next week so i have to wait anyway.:)
 

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I'm gonna check mine if the match with the data from infinity.

Maybe i tune the box a little bit lower, I'm gonna think about it.
I buy the wood next week so i have to wait anyway.:)
Ok, I see you entered a lot of the data and I had winISD calculate a lot of it. The general thinking used to be winisd did a better job of calculating it then the mfr data.. not sure if that changed. You can tell by the green (manually entered) vs blue (calculated) fields.

Not really of any consequence.. but David's rolloff was way steeper than mine.

I would tune a bit lower.. the sealed subs are performing admirably at the higher frequencies. Either way it's gonna be loud :D

Tim
 

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Discussion Starter #13
Ok, I see you entered a lot of the data and I had winISD calculate a lot of it. The general thinking used to be winisd did a better job of calculating it then the mfr data.. not sure if that changed. You can tell by the green (manually entered) vs blue (calculated) fields.

Not really of any consequence.. but David's rolloff was way steeper than mine.

I would tune a bit lower.. the sealed subs are performing admirably at the higher frequencies. Either way it's gonna be loud :D

Tim
Haha, the louder, the better!:D
 

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You can model the subs up to about 16-17mm instead of stopping at the 13mm line.

You may want to tune a little lower with a bit bigger box, see what a 100cm port looks like with a 400 liter box size.
Do you know if the same holds true for the JBL GTO1214 that seems to be the same sub?
 

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Discussion Starter #17
hello everybody,

I had finally some time this week to build the sub.
Here are two pictures.



The subs are connected in series to one channel of a inuke 3000 dsp.

So far, i'm not blown away by the bass, I'm thinking to wire the subs to two ohms for more watts.
And i still need to buy a mic to measure the response. :)
 

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i would say try it in 2 ohms, then set a limiter at max rms, i believe that to be 600 total for the 2. as others have stated, these can be pushed a little past xmax.
 

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Thanks for your replies.
i would say try it in 2 ohms, then set a limiter at max rms, i believe that to be 600 total for the 2. as others have stated, these can be pushed a little past xmax.
I have wired the subwoofers now in two ohm, thats a lot better. The limiter is now at 700 watt, according my simulations they can have 800 watts but this is good for now.

I am pretty much in the same boat as you. Built four X 4.5 cuft net slot ported Infinity's boxes tuned to 18hz and put one in each corner of my tiny 14X13 theater.
Was impressed at first by the output, but have noticed that the really low stuff isn't much better than my old Paradigm ported sub. Some quick rough measurements indicates that the "Holy Grail" of diy subwoofer bargains doesn't seem to perform anything like it models, in room or out in an open space. There are lots of modeled charts on AVS, but only one measured response that I could find, and it tends to corroborate my own. MFusik was going to measure his ported Infinity, but that was 3 months and a thousands posts ago so I hold little hope. If you do get a mic be sure to post the response. I really do need to get a UMIK-1 and a Mini-DSP myself.
Here is the thread where I was whining previously. :)
http://www.avsforum.com/forum/155-diy-speakers-subs/1922505-why-aren-t-there-more-1260w-1262w-builds-2.html#post33016585
I agree with you.
I have ordered a umik-1 so that i can measure the response of my 1260 sealed and ported.
When the mic is delivered i will post some measurements.
 

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I just built a 1260w sub and based on comments in my build thread I went ahead and upgraded to a new denon x2100. The sub is still powered by the Dayton plate amp.

I just watched Edge of Tomorrow and Transformers at -10. Through various parts the floor has been shaking, various random things rattling around the room, front door rattling, etc.

It definitely has the same general feel as being in a movie theater. I agree it just doesn't have the ability to move enough air to feel like standing at a concert, but the whole build was 250 dollars. I have a graph of the response at 75db, it is pretty flat. I haven't had time to push it to its limits and measure it.

My build was down firing 24 x 24 x 24, with shelves in the front for DVDs, so net is 3.7 cubic feet (about 100 liters). The port is 17.5 inches long and 4.5" square. I did use Unibox instead of WinISD to calculate port length based on how the port interacted with the edge of the subwoofer box (this was based on some posts by LTD02 about ports being close to the edge instead of a centered port). WinISD wanted a much longer port. I wonder if the actual tune ended up being different than WinISD calculated and it shifted the response from the low end?
 
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