Dual GR Research SW-12a Project - Home Theater Forum and Systems - HomeTheaterShack.com

Old 05-05-12, 08:25 PM Thread Starter
Shackster

Join Date: Feb 2011
Posts: 10
Dual GR Research SW-12a Project

I am looking to start planning a enclosure project using two SW-12A subwoofers from GR Research. They recommend using 2.6 cubic feet tuned to 20hz for best performance per driver. Below are the parameters:

SW-12A parameters:
Mechanical Parameters:
* Fs = 20.5 hertz
* Qms = 4.85
* Vas = 3.56 cu.ft or 101 liters
* Cms = 0.057 in/Ib
* Mms = 5.964 oz or 169.1 grams
* Rms = 9.843 Ibs/sec
* Xmax = 16 mm
* Sd = 72.5 sq.in or Dia = 9.6 in or 244 mm
Electrical Parameters:
* Qes = 0.440
* Re = 6.7 ohms
* Le = 5.16 mH
* Z = 8.0 ohms
* BL = 18.5
* Pe = 200.0 watts
Combination Parameters:
* Qts = 0.40
* Sens = 87.03 dB (2.83 V)

I plan on building a box 5.2 cubic ft tuned to 20hz. I have done some modeling in WinISD using 500 watts (Oaudio amp).

Can you please let me know which port size would be best? Single 6", dual 4" ports or a slot port. This is for mainly HT with a little music use.

Thanks in advance for the help
jbracing17 is offline

Old 05-12-12, 11:32 PM Thread Starter
Shackster

Join Date: Feb 2011
Posts: 10
Re: Dual GR Research SW-12a Project

I think I decided to go with two square ports (4.25" x 4.25"). The port velocity looks to be .06 in WinISD so I assume that is acceptable unless someone say it is not. The program calculated a port length right around 42.75" to achieve the 20 hz tune in a 5.2 ft^3 box. Does that sound right? I used some other calculators I found online and the result ranges from 41.17" to 43" or so. Please let me know if I am on the right track. The amp arrived this week and the other woofer is set to arrive next week. So I would like to start construction this weekend.
jbracing17 is offline
Old 11-03-12, 02:10 PM
Senior Shackster

Join Date: Jul 2009
Location: Iowa Park, Texas
Posts: 279
Re: Dual GR Research SW-12a Project

I meant to respond to this much earlier but somehow it slipped my attention. Those number all look spot on. How did your project work out?
Danny Richie is offline
Old 11-03-12, 03:39 PM Thread Starter
Shackster

Join Date: Feb 2011
Posts: 10
Re: Dual GR Research SW-12a Project

Thanks for the response. I actually jumped ship on the ported design even through I spent quite a bit of time designing it. I was able to purchase two PR12a for a very good price so I am back to the drawing board on this. I will keep it to 2.4 per driver and PR. I just need to decide if I want to build two seperate boxes or a single box with seperate chambers. I am working on the single box right now. I plan on using braces similar to what use in your servo boxes. They make the most sense.
jbracing17 is offline
Old 11-03-12, 03:46 PM
Senior Shackster

Join Date: Jul 2009
Location: Iowa Park, Texas
Posts: 279
Re: Dual GR Research SW-12a Project

Here are some plans using the SW-12A and the matching PR: http://gr-research.com/pdf/sub.pdf
Danny Richie is offline
Old 11-03-12, 04:03 PM Thread Starter
Shackster

Join Date: Feb 2011
Posts: 10
Re: Dual GR Research SW-12a Project

Excellent. Now that is service. Is there any reason that I cannot shave 2 inches of depth off and make it up in other dimensions? Thanks again. About how much no rez is needed for two of these cabinets?
jbracing17 is offline
Old 11-03-12, 05:03 PM
Senior Shackster

Join Date: Jul 2009
Location: Iowa Park, Texas
Posts: 279
Re: Dual GR Research SW-12a Project

So long as you keep the same air space then you can manipulate the shape.

Place No Rez on all four sides between every brace.
Danny Richie is offline
Old 11-03-12, 08:25 PM
Elite Shackster

Jack

Join Date: Apr 2008
Location: Evansville, Indiana
Posts: 1,695
My System
Re: Dual GR Research SW-12a Project

Then you can have something that looks like this when all the spacers are filled in and the outer cabinet is almost finished.
With the driver installed but the top edge radius pieces missing, it is an imposing subwoofer to be sure. I had to listen before I did the finish, it was begging me to plug it in. I just had to....

Oh and yes Danny that is a Lite Audio Dac you sold to me some years ago.

Good Listening

Jack

"For those who believe no proof is needed for those who don't believe no proof is possible"
Savjac is offline
Old 11-03-12, 11:27 PM Thread Starter
Shackster

Join Date: Feb 2011
Posts: 10
Re: Dual GR Research SW-12a Project

Thanks for the pics. I think I am just going to stick to the original plans that Danny linked and do a single enclosure that houses everthing. Do I need 1 pc of No Rez per Chamber?
jbracing17 is offline
Old 11-04-12, 07:01 AM
Elite Shackster

Jack

Join Date: Apr 2008
Location: Evansville, Indiana
Posts: 1,695
My System
Re: Dual GR Research SW-12a Project

I believe that is what I used one full piece.
The sheet is pretty large and goes a long way. Make sure once you are ready to stick it to the wood, that everything is the way you want it because that stuff sticks like crazy. On the upside, it works very well. I have used it for other speakers and it does a wonderful job.

Good Listening

Jack

"For those who believe no proof is needed for those who don't believe no proof is possible"
Savjac is offline

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