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Discussion Starter #1
Folks,

Some of you may have already responded to my other thread...and Thanks to all your advice I've now decided to embark on a (very ambitous for newbie) DIY subwoofer project.

This new thread is just to seek a wider audience for guidance... The goal being to build the cleanest, high-fidelity sub possible in DIY... as the sub will be used mainly for music and should unobtrusively extend the range of the mains I plan to get (Genelec G Four / 8040).

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
10. Features: Comparable to the ADAM Sub-10
11. Remote control?


Need recommendations/guidance on the following:
1. Cabinet Type
Considering Sealed dual push-pull cabinet due to ease of design and build.

2. Driver/Amplifier/Kit

Which driver or kit should I get?
I'm thinking restricting myself to Aluminum cones - any advice?
Can you guys suggest if I should go with 12” or 10”? Focus again is fidelity and not loudness.
can you folks recommend the best brands and makes with very long excursion 10" or 12" drives

One recommendation I have received so far (Thanks Maxmercy)

"DIYSoundGroup. No need for expensive tools, just glue, clamps, a drill, some paint.
Dual Opposed 10" cabinet would be good for your needs, and fit the WAF. Build two. Use the Dayton reference drivers."

What about Scanspeak, Seas and Peerless and any others?

3. Amplifier:
Which amp type is better 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?
What is the minimum power I will need for a 10" or 12" sealed dual based on amp type and driver size?

4. Cabinet Material:
Would Hard-wood cabinet (instead of MDF) offer any advantages over MDF?

I also have the option of GRP (figerglass) or aluminum for cabinet - would this be worth exploring 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 what are 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 around $2200 for the pair (based on US prices of components, before shipping, taxes and customs).


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 can consider Peerless drivers (made in India - but its not easy to get them locally) - 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 the same on AVS and Data-bass.

Thank you all in advance for any and all responses.
 

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First off, I think your power rating is a bit too low... You need at least 1,000 watts for most dual 12" subs designs.

Amp designs are not important as the power output... Class D amps run more efficient and are smaller in size than Class AB.

I would not consider hardwood over MDF. MDF has consistent density whereas hardwoods are not due to knots, age and growth patterns. You need denser materials as it reduces resonances... Fiberglass would definitely be a no-no.

If you want accurate bass, you will need to figure out the box size from the Thiele-Small parameters to get a low Qtc. A Qtc below 0.7 will give a tighter response at the cost of some low output, above 0.7 will give you more bass with some boom at the frequency peak. Some people go as low as 0.6 or lower for tighter bass.
 

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Discussion Starter #3
Thanks jon:

Will look into Thiele-Small paramenters...

as for sealed vs ported - is it possible to replicate the Genelec LSE design? how difficult is to implement and is it worth giving a shot?


One of the advantages of being in India is that I have some really wild choices for cabinet material - for eg... Given a drawing I could get a solid box made in granite, onyx ("transparent marble"). If density and inertness is the main criteria - then I gez no-one can beat natural stone... I'll give it a shot with granite or marble If you guys think it could offer some performance advantage...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.


Drivers -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?
Many have recommended Dayton - but that means shipping, import duties etc and in that case I probably should also consider Scanspeak (Vifa) or Seas and any other makers?

Amp: Not sure if there are any good local Indian makers of amps... so I'd have to look east (China/Taiwan) for it... in that case what are the makes/models to consider?
 

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$1000 for a pair of 12's would be enough to have killer bass. Peerless make some nice woofers but prefer the TC Sounds over them.
http://www.parts-express.com/pe/showdetl.cfm?partnumber=293-658
And if you want even more SPL then there are more 12" car audio woofers to chose from for the same price or much less. BUT 2200 for everything should be easy. The LMSR 12's MiniDSP and a big amp and your set.

I know of only one Indian amp company and I am still waiting on them to put their products out. They have some awesome numbers as far as wattage but they most likely wont have a product for another few months.
 
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