New to DIY, Subwoofer 10" or 12" dual push-pull - please guide - AVS Forum
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post #1 of 5 Old 08-28-2013, 01:40 AM - Thread Starter
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Folks,

I've been posting at the other forum threads and based on what was recommended among the manufactured subs and my constraints it took me a long time to decide to embark on a DIY sub project...

The goal is to build the cleanest, high-fidelity sub possible in DIY.. as the subs will be mainly for music and should pair well with the Genelec G Four (8040) I plan to get for the mains.

Following are the key requirements:
1. Building a High-fidelity, clean, distortion, rattle free and musical sub is the most important goal - not earth shattering bass, loudness or SPL.
2. Performance: looking to get equal or better fidelity and performance comparable to the Genelec subs 7060 (19Hz, 10" driver with 120Wamp) and 7070 (19Hz, 12" with 250W amp). The mains have a 6.5" (90W) woofer and the sub need only be big/powerful enough to complement it - therefore I'm thinking no more than 10"(400W) or 12" (800W).
3. Max. Cabinet dimensions: 18" x 18" x 24"
4. 10" or 12" - dual opposed drives - for vibration/rattle free bass.
5. Inputs: 1 x XLR, RCA for LFE (with low-pass set at 120Hz), 1 x XLR, RCA for Left/Right input (with low-pass set at 85Hz)
6. Outputs: 1 x XLR, RCA (for LFE loop out), 1 x XLR, RCA with high-pass to connect the Left/Right mains
7. Level control & Clipping protection
8. Detachable power cord with 220V/50Hz input and Power surge protection
9. Auto-power on signal, Remote control and in general "nice-to-have" features comparable to the ADAM Sub-10



Need recommendations/guidance on the following:
1. Cabinet Type
Considering Sealed cabinet - easier to design and mainly for fidelity and vibration cancelling reasons and for ease of build- than having to optimize or tune the port etc which can be quite complex. If a ported design may be more power efficient and give better extension without loss of fidelity then may be I'd like to do something inspired by and along the lines of the Genelec LSE.

2. Driver
I'm thinking Aluminum cone - any advice?
Can you guys suggest if I should go with 12” or 10”?
can you folks recommend the best brands and makes with very long excursion 10" or 12" drives

3. Amplifier
Which amp type Class A/B or Class D?
Which brand? suitable for the recommended driver and cabinet type. Are the features for high-pass/low-pass Filters and inputs and driver overload protection and power-on mute circuitry built into the Amp?

4. Cabinet Material:
Would Hard-wood for cabinet (instead of MDF) offer any advantages?
I also have option of GRP (figerglass) or aluminum for cabinet - would this be worth considering? would Aluminum be worth it and offer any performance or fidelity advantages?
If its Alumin or GRP, I'm considering a cylindrical shape with the top and bottom rounded out (much like a medicine capsule)... any advice on this?

5. Power source and all the other components I will need to accomplish the above?

6. Budget: What should the budget be to achieve the above goals. Although this is the least of the concerns - if possible I'd like to keep it around $2200 for the pair (based on US prices of components).

7. Location: I'm based in Bangalore, India and have access to a carpenter, metal worker, electronics assistant and may also able to get the speakers tested or measured at a lab in a research institute near-by.I an consider Peerless drivers - but not sure how low they extend - any other brands I'd have to keep in mind any components imported from outside India will incur an additional 70% in shipping duty and taxes.

I'm also posting this on HTS and Data-bass

Thank you all in advance for any and all responses.
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post #2 of 5 Old 08-28-2013, 06:54 AM
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No need to spam all the HT forums. rolleyes.gif
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post #3 of 5 Old 08-28-2013, 07:08 AM
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Just as a wild suggestion...



... have you thought about researching the above questions and then posting your findings with some initial proposals for comment?
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post #4 of 5 Old 08-28-2013, 12:32 PM - Thread Starter
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@nograveconcern:
Thanks for your earlier reply - which has since been edited...
I will stick to your original questions/suggestions:
1. Living/Dining hall: 25' x 18' open to a Foyer: 9' x 12' with Ceiling height 10'. 4BHK layout.jpg 775k .jpg file Flooring is polished marble, walls are brick with cement plaster.

2. I'd be more than happy if it can deliver the performance of commercial options...
Freq. Resp: 19Hz - 120Hz
Maximum short term sine wave, SPL output averaged from 30 to 85 Hz, measured in half space at 1 meter >= 108db SPL
Maximum peak SPL output with random pink noise, measured in half space at 1 meter >= 113dB SPL
Self generated noise level in free field @ 1 m on axis ≤ 15 dB
Amplifier system distortion at nominal output THD <= 0.05%

3. You are suggesting a Ported build and dual 12"? - whereas the Genelec 7060 is achieving the above with a ported single 10" and 120W amp?
I don't know if I have the confidence yet to do a good enough ported design and do the appropriate tuning etc... unless of course someone here can tell me that the Genelec LSE design is fairly easy to implement and worth a shot.

4. Looked into Dayton Reference - but I'm leaning towards Peerless drivers - as they are locally made in India and I can try to find out if there is any cost advantage over importing, paying shipping/duties etc.
Parts Express has the - Peerless 835017 12" Aluminum Cone XXLS Subwoofer with freq. response down to 19Hz (whereas the 10" driver from the same line is rated at 22hz)

If quality of the driver is the most important - then would Peerless still be the first choice?
I know you all have recommended Dayton - but that means shipping, import duties etc and that means I probably should also consider Scanspeak (Vifa) or Seas and other makers?

5. Can you point me to some material on MiniDSP that you referred to? Apart from Behringer iNuke - any other amp males/models to compare to?

6. Since I'm in India I have some really wild choices for cabinet material - for eg... Given a drawing I could get it made in granite or marble if it turns out to have some performance advantage. So should I consider granite or marble?
The only issue is finding some good way to mount the drivers and that too can be arranged with pre-drilled holes and filled with some resin for the driver and amp. plates to be screwed on.


@Max:
I know a lot more research is pending and has to be done.. my post was in the hope that I could narrow down my choices before digging further...
1. Cabinet type: Based on my research it became clear that sealed designs are easier to do and offer clean bass but the really low freq extension is harder... The matter is almost settled unless someone here has designs that are similar to LSE ported design of Genelec

2. Driver/Amp/Cabinet Material - see above...
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post #5 of 5 Old 08-28-2013, 01:01 PM
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I think 2 ported 12's is a good direction to go. I would separate them into 2 separate boxes. I'm not up on the quality of peerless subs in general. That driver specifically is extraordinarily expensive for the performance potential I see in it. The HO 12, at about 1/2 the cost in the US, would be a much better choice due to higher usable excursion (20mm vs 12.5) and possibly better inductance control (I don't know what is meant by "distortion canceling fixtures").

Of course I would go with as large of a driver as your budget and space allows. You could likely surpass the performance of a ported 12 with a sealed 18 in the same size box.
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