Home Theater Forum and Systems banner

1 - 20 of 20 Posts

·
Registered
Joined
·
162 Posts
Discussion Starter #1
I am designing a subwoofer for our new home theater setup. I have the Yamaha RX-V663 receiver with 7.2 outputs. I have a Yamaha stereo amp we don't use now.

Ideally, I would hook up 2 identical subs, one for each channel, at 100w per channel into 8 ohms. Another way I thought to do it would be to have 2 speakers in one cabinet and use one channel for each. I would have access to the 200 watts either way.

Could I somehow "parallel" the two channels to get 200 watts into one "bigger" speaker. I understand many commercial or contractor amps are bridgeable in this way. They can also power 2 ohm loads which the Yamaha should not do. The manual for the Yamaha does not show this being possible with this model amp, AX 592.

To sum it up, it would be convenient for me to use our existing amp for the sub. I believe it will drive a ripole with two opposing 12" speakers. For the same money I can build a dipole with a single 21" speaker. I would like to do that if I can give it the 200 watts available. Is this safe and doable? :huh:
 

·
Premium Member
Joined
·
1,941 Posts
Unfortunately I don't believe so. If it is not bridgeable so you'll have to use it as a 100 W * 2 channels. And anyway, I doubt that would be enough for powering 2 subs.

You should reconsider an amp to have a proper result :hide:
 

·
Registered
Joined
·
162 Posts
Discussion Starter #4
I am considering an opposing W configuration for 12's or 15's. I am considering an N configuration for an 18" or 21" driver.

http://www.boxenselbstbau.de/hifi/index_en.htm?/hifi/aka_geh_en.htm

http://www.boxenselbstbau.de/hifi/index_en.htm?/hifi/aka_geh_en.htm

The second link looks like a nice design for a 21" driver.

The 21" driver I am considering is described as; Pyle :pDW21250 21" performance optimized high power subwoofer.
freq. response - 22hz to 4khz
power handling - 1000 watts rms, 2000 watts peak power
8 ohm impedance
4 inch voice coil
350 oz magnet

This driver does not have much in the way of published Thiele parameters that I could find, however, it is built to be a big mutha premium subwoofer and sold by a company dealing in audio and subwoofers. I don't believe my ears will hear anything wrong with it. It is available in Canada as far as I can tell.

Our living room is small and already populated by 4 - 15" woofers, just not subwoofers.

Re. the Yamaha power. This amp is quite heavy. I have never turned it up past 3/4's. I understand that Crown, QSC, etc. give you a real use rating of their products. Pyle, Gem, and some other imports advertise 2000 watt PA amps that put out 200 rms watts per side in to 8 ohms - only double the Yamaha spec. This area is gray for me. I can also choose to home build a high power solid state amp or buy components and piece one together, but that will really eat up some time. Whew :dunno:
 

·
Registered
Joined
·
132 Posts
For the quality of the pyle driver stay away save your money and get a good subwoofer instead. Amp wise stay away from PYLE and GEM again and all other cheap brand, better buy once cry once then to buy twice and kicking your self to have not bought the right stuff to start.

Depending on your budget a SDX15 http://www.creativesound.ca/details.php?model=SDX15 or this http://www.mach5audio.com/zen/index.php?main_page=product_info&cPath=65&products_id=181 in a sealed or vented box and a Behringer 1500 or Tapco J1400 would be a safe bet and shake your house, if you plan for 2 subwoofers get the Behringer 2500 or the Tapco J2500, for cheap amp these 2 are probably the best money can buy.
 

·
Registered
Joined
·
162 Posts
Discussion Starter #6
Amp wise stay away from PYLE and GEM again and all other cheap brand, better buy once cry once then to buy twice and kicking your self to have not bought the right stuff to start.
I tend to agree. Nice of you to back up my suspicion. Yes I would like a Tapco or Behringer amp to drive one or two subs. Since Mastercard is financing the driver and plywood purchase, I would like to try and get by using the Yamaha for 6 to 12 months, maybe longer if it does the job.

If I had a bridgeable amp I would go for the SD15. Since I don't, would it be unwise to try 2 - SD12's?
If choosing 2 - SD12's, would an opposing W ripole be OK? I like the idea of a small, relatively simple cabinet supplying front and back waves.
 

·
Registered
Joined
·
132 Posts
I tend to agree. Nice of you to back up my suspicion. Yes I would like a Tapco or Behringer amp to drive one or two subs. Since Mastercard is financing the driver and plywood purchase, I would like to try and get by using the Yamaha for 6 to 12 months, maybe longer if it does the job.

If I had a bridgeable amp I would go for the SD15. Since I don't, would it be unwise to try 2 - SD12's?
If choosing 2 - SD12's, would an opposing W ripole be OK? I like the idea of a small, relatively simple cabinet supplying front and back waves.
I do not know why you want to build a w or other type of box :hide:, and you will have to figure out a speaker with the right parameter that can fit for that particular application :reading:.

You wrote you want it small and simple cannot get any more simple then a sealed box just follow the suggested box here http://www.creativesound.ca/pdf/SD12-16inCube-plans3.pdf for their 12 inches, also i'm not sure your Yamaha can handle 4 ohms load anyway they do specify 100 watts per side at 8 ohms and 120 watt at 6 ohms nothing about 4 ohms other then dynamic power at 4 ohms 220 watts that just puzzled me:dontknow:. You can give it a try and always look at a plate amp when money is ok but again this will be close to a EP2500 money wise but performance wise way better with an EP2500.

Also you haven't post the size of your room or your expectation from the sub you want to build, you should check that because you may end up disappointed at the end if you do not do it right the first time. if you are expecting this :hsd: and have this :thumbsdown: you will have to do it all over again:spend:.
 

·
Registered
Joined
·
162 Posts
Discussion Starter #8
Hi
The room is 13'6" x 16'.
The cabinet choices all have pros and cons, some that I do not know. Sealed need extra power compared to ported. Ported need tuning based on size and design. Horn type are larger and harder to build.

I do want to do it as right as possible the first time. Before I spend $250 for a 15" sub that will do the job, I want to be confident that this 18" sub for $120 won't do the job. I understand my amp isn't that great. Eventually I will have an amp that is good to go for this purpose. :innocent:

http://www.audiopile.net/products/Speakers/APX-1841/X-1841_cutsheet.asp
 

·
Premium Member
Joined
·
1,941 Posts

·
Registered
Joined
·
132 Posts
Hi Again i do have 2 sealed SDX15 in 2 boxes of 3,4 cft each just like these one http://www.hometheatershack.com/forums/diy-subwoofers-sealed-ported/11241-sdx15-mid-q-sealed-enclosure-pics.html hooked up to a QSC MX3000A (1200 watts per side)and i do have more bass then i need:jump: my room is 13X24X8 high. The speaker you refer is useless for HT sub duty. Like you said horn load would have to be monstrously large to do sub. If you want a 18 check this 265 $ canadian delivered to you door. http://www.mach5audio.com/zen/index.php?main_page=product_info&cPath=65&products_id=181
 

·
Registered
Joined
·
162 Posts
Discussion Starter #11
If you want a 18 check this 265 $ canadian delivered to you door.
Thanks very much. I had forgotten about that company. They have something I am interested in now, the MJ series. I have also decided to get a new amp when the subwoofer is finished. I can probably sell the Yamaha locally to someone still into stereo, as I was for many years. :hiya:
 

·
Registered
Joined
·
162 Posts
Discussion Starter #13
Put the MJ-18M in 10 cu.ft tuned to 18 hz and you'll have a decent HT sub for $155 shipped.
I expect to get the ball rolling on this shortly. I started using the WIN isd program and modelled a few tentative sizes. 12 cu. ft. at 16 hz tune looked interesting as well. I can choose the tune closer to the finish line though.

I do not know how much "flat response" I have ever experienced. I crank the bass up full on the TV and on the receiver. This could be producing a bass hump, or just be reducing a rapid falloff curve. I can't seem to get enough of it though. :party:
 

·
Registered
Joined
·
162 Posts
Discussion Starter #15
I ordered the MJ-18m today. I will be tuning the EBS box to 19 hz with 3 - 4" tubes, as suggested by Mach 5. :drive:
 

·
Premium Member
Joined
·
1,941 Posts
Why not a single 8"? Easier construction...
 

·
Registered
Joined
·
162 Posts
Discussion Starter #17
Why not a single 8"? Easier construction...
I'm not sure exactly why to go with 3 - 4 inchers but it sounds like a cool idea. I do know 4" is a choice available in Win isd. I guess when I tabulate the volume and subtract for speaker and brace volumes, I will be able to plug it in easy. Lots of the design is tentative right now though. I just noticed a mistake in my available space measurement so I need to think that through again. :laugh:
 

·
Premium Member
Joined
·
1,941 Posts
If you can manage to build a 8" port, it takes 3 times less effort than 3 * 4" ports, and 3 times less possibility for errors in construction.

You have to play with WINISD to check length of port, and port resonance. I haven't, but could do it if you need.
 

·
Registered
Joined
·
203 Posts
If you can manage to build a 8" port, it takes 3 times less effort than 3 * 4" ports, and 3 times less possibility for errors in construction.

You have to play with WINISD to check length of port, and port resonance. I haven't, but could do it if you need.
Modeling a 10cf with a 19hz tune an 8 Inch port will need to be roughly 30 inches long with a resonance of 222.28hz :T With 600 watts input power maximum air speed will be 22.5ms at about 17Hz, this is without a subsonic filter which would be needed

Three 4 inch ports would need to be roughly 24 inches long and the air speed with the same input power would be higher, peaking at 30ms

I vote an 8 inch port...
 

·
Premium Member
Joined
·
1,941 Posts
I have not made any modeling but by experience and sense... a 8" is better, but 3 * 4 " give options to play with :neener: like multi-tune a la SVS?? This feature is great to play with in the bginning, but will be useless once mind is made...
 
1 - 20 of 20 Posts
Top