My First DIY Subwoofer using Eminence Lab 12

Surrealistix

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Joined
May 14, 2008
Messages
187
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Location
Navi Mumbai
I got the idea of building a Subwoofer when I realised that the shipping cost for a HSU VTF MK3 subwoofer from the US would be as much as the cost of the subwoofer itself.

I started doing some research a couple of months ago, and finished my first DIY Subwoofer build a couple of weeks ago.

I didnt know a thing about building a subwoofer two months ago, with a lot of reading and some help on forums, I am pretty happy with the outcome of my first DIY endeavour.

Functional Goals:
  • At the minimum, sound significantly better than my Polk Audio PSW 500 subwoofer in my HT setup
  • Should sound as good if not better than subwoofers available in 50K to 80K for HT use
  • Total costs should be under 30K its too risky to spend more on my first DIY project
  • A big bonus if the sub integrates well in my stereo setup
Design Goal:
  • Should sound reasonably flat down to 25 hz (in room)
  • Group Delay should be kept below 6 to 8 ms above 30 Hz
  • Port air velocity should be under 17 m/s
  • It should be able to reach 105 db SPL without exceeding cone excursion limit of the driver
Implementation:

The Eminence Lab 12 looked like a really good driver and was available at a reasonable price in India. Other than importing a driver, I didnt find any other 12 inch driver that would be suitable for a subwoofer in India.

I was very keen on building a sealed sub, but the Lab 12 didnt seem to lend itself to a sealed design. I spent a lot of time with WinISD and Bassbox pro and read up extensively on forums to finalise on enclosure design which comes close to my design goals.

I finalised on a 163 litre box with two front ports tuned at 17 Hz. The effects of the port seems to kick in below 30 Hz and it didnt require any boost using parametric eq or Linkwitz Transform.

Given that I didnt need any active eq with this design really helped, as this is my first project and it certainly helps to keep things simple.

Amplification: I was contemplating getting an O Audio plate amplifier based on recommendations from Ashok on the forum, but finally went with a pro-amp as I didnt seem to need a cross-over or eq. The Tapco juice 2500 was available for the same price as the O Audio plate amp with 4 times as much power (2500 watts at 4 ohms). I didnt need any of that power for my current project, but I figured that I may want to run two subwoofers so the pro-amp seemed to be a more future proof choice.

Here are some pics of my Subwoofer (I havent worked on the Veneer as yet).



The Amp on the bottom left on the rack is the Tapco Juice 2500 Pro amp



Here are the graphs from WinISD for my Subwoofer:

SPL


Cone Excursion


Group Delay


Port Air Velocity


Amplifier Apparent Load power(VA)





Setup:

HT: I am simply using the LFE from my Denon 3808 receiver going into the Tapco amp (Bridged Mono). I used the Audyssey EQ on the receiver to setup the crossover and levels. The setup was simple and sounds really good.


Stereo: I dont use the Subwoofer in my Stereo setup as it feels unnecessary. The Usher BE-718 speakers go really deep down in my current setup. Since I made this baby with my very own hands, I have to use it in my Stereo setup anyway (welloccasionally). :angel

Since I use my PC as the front end, I decided to use a software cross-over plug-in on Foobar. My M-Audio sound card can do SPDIF out (bit matched) and LR (Balanced analogue) simultaneously.

So I have the SPDIF out connected to my external DAC for the front speakers. This ensures that I dont touch the Stereo signal path in anyway by adding the sub. I can switch on the Sub by enabling the crossover plug-in and using LR analog output summed mono feeding into the pro amp. The Foobar crossover plug-in allows all kinds of cross-over tweaking and I have been playing around with these settings.

foo_dsp_xover


I am reasonably convinced that my Usher BE 718 speakers dont really need any assistance from the Subwoofer except for may be when I have a party in my house listening to music that needs to shake the floor. I tried the sub with my smaller Usher S 520 speakers and found the two integrated really well.


Overall, I am super happy with my first DIY Sub. It sounds tight, goes deep and can play really loud without breaking a sweat.

Parts and Cost:

I still need to veneer the box, but the cost so far:
  • Eminence Lab 12 driver: Rs. 8,500 shipped to Mumbai from Cinetekk Chennai
  • *Tapco Juice 2500 Pro Amp: Rs. 19,500 from Narain Pro Audio, Lamington Road, Mumbai
  • 8X4 MDF sheet Rs. 1400
  • Carpenter, glue and other misc cost: 1200
  • Total: Rs. 30,600
* I could have gone for the Tapco Juice 1400 or Juice 800 and saved Rs. 7000 to 10,000 bringing the overall cost down significantly.
 
Nice setup Surrealistix, must visit Mumbai at some point :)

The real gem which no one asked about is actually the green two chassis unit directly behind the Usher power amp :D

enjoy!

cheers
[email protected]
 
I didnt know a thing about building a subwoofer two months ago, with a lot of reading and some help on forums, I am pretty happy with the outcome of my first DIY endeavour.

could you let me know what did u refer to b4 starting off ?hv u done any other DIY projects or was this the first ?? seems gr8 to start off with a sub imo ...
 
Last edited:
Very nice ..... congrats ...... I bet the eminence driver is sweet. We use eminence speakers for surround duty in my cinema theater.

Also wanted to know whether I can use a car audio subwoofer with box and a car sub amplifier at home. I want to hook it up to the Audioengines A5 i plan to purchase.

Is this doable ?
 
grubyhalo - Its available from ARN systems on a discount. Check out Sridhar's thread, it's on sale with a 22% discount. Should be a little over 1 lac.

cranky - The Sub is quite big about 28 inches tall and 23 inches deep and 19 inches wide. The fan on the Tapco doesnt switch on when I am listening to music at regular levels at all. If the amp runs for long and loud, then it does come on,but I notice the noise only when I put turn down the music. When I bought the Tapco, I was prepared to put it in the next room and drill a hole through the wall to run the cables. I don't think that will be necessary.

The PD Dac is mind blowing. I have the m-audio connected to it directly over SPDIF. The entire stereo chain starting with the PD Dac, then to the Shindo Pre, Usher r 1.5 Power and the Usher BE 718 has come together really well. I am thrilled to bits with my current setup. I think the Shindo pre (yes the green box in the middle) and the PD Dac works like magic.

I will posting pics of my complete setup within the next couple of days.


I sold the Odyssey amp to a friend.

maniac_2004:
I tried to ready everything I could find on the Internet. Got really overwhelmed, then confused and finally after a few weeks of research I got my head around the basics and felt that a Subwoofer was probably a good place to start my DIY hobby.

I have a built a Monica Dac2 from a kit before this, but that was just a few hours of soldering - not much fun.

audiodelic:
I have seen some posts where car sub drivers have been used for a home sub, don't really know if it will sound good. You will simply need to use WinISD, punch in the parameters and see if it works.

Here is another pic of the sub showing the insides of the Sub:
 
Great work! What did you do for woodworking? Do you have table saw and other tools? Can you please share details on that? How did you join the wood panels, what material did you use etc?

Regarding the amp and woofer, can you please share the contact details of the dealers?

It is very aspiring. I too was planning to enter into DIY with a sub, which should be much easier than building a 3 way speaker. I do not have any tools/ space to woodwork, painting, so I might look at a carpenter.
regards
 
anm:
I had my carpenter do all the woodwork. He is pretty good and more importantly follows instructions to the tee.

I joined the panels using Areldite and nails. I am currently using .75 inch MDF, I think I need to have a wall thickness of 1.5, so will be doubling all the exterior panels.

I got the Amp from Narayan EPro Audio: Narain : Proaudio Lighting Pvt. Ltd for a little under 20K

I got the Eminence Lab 12 from cinetekk.co.in in Chennai

If you are in Mumbai, feel free to come home and check out my Sub.
 
anm:
I had my carpenter do all the woodwork. He is pretty good and more importantly follows instructions to the tee.

I joined the panels using Areldite and nails. I am currently using .75 inch MDF, I think I need to have a wall thickness of 1.5, so will be doubling all the exterior panels.

I got the Amp from Narayan EPro Audio: Narain : Proaudio Lighting Pvt. Ltd for a little under 20K

I got the Eminence Lab 12 from cinetekk.co.in in Chennai

If you are in Mumbai, feel free to come home and check out my Sub.

Hey Surrealistix, the bracing behind the driver looks like particleboard. Is it?
Also, the brace - is it also bracing the driver? Can't be too sure from your pic. but I think it does not. Maybe if you can brace the driver with a rubber bush between the bracing and the magnet...
 
Hi Keith,

I used MDF for the cabinet and the bracing.

I didn't think about bracing the driver. But, I guess it might help. I will try that out next time I open up the box.

Thanks!
 
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