Dual Sonosubs Conflicting info Help?

[chirotude]

I have tried to read as much info as possible on two separate subs but I am more in limbo than ever. I have 2 shivas and 2 AV250 plate amps. I have built one sono sub so far. Results in my partially built HT, with sub corner loaded in the front right, sounds great. No fancy reading sorry.

My Question is if I use other shiva and amp to build an identical setup for the front left corner what would my advantages/disadvatages be. I will use the AV250 set at ~ 60-80Hrz to blend with future kit281 for mains. My Sonosub will be ~ 200L 18" tuned to about 16. My walls of the HT are insulated etc including above my drop sealing. Dedicated HT room 22'Lx13'Wx8"H.

Please go easy on a new guy. thanks in advance.

Doc

[johninCR]

For music many guys prefer to use 2 separate subs run in stereo, but I suspect that you have a mono sub out. For HT 2 just gives you the additional problem of proper placement of a second sub. With multiple drivers I prefer a setup where the mechanical energy of the drivers cancel each other out and, if possible, in a push/pull alignment to further reduce distortion.

[chrish]

I am in the middle of a similar project, however I am interested in music more than home theatre. The way that I am handling the issue of stereo sub woofers (rather than dual mono) is to bypass the sub woofer output of the surround sound amp/receiver completely. I have a rotel surround pre-amp, and will be setting speakers to large and setting sub woofer to none. This way the low freqs of the left and right channels will not be stripped and blended to a mono output, but rather will remain with its respective channel. I am building an active crossover to then split this signal to get 1. Left (high and midrange) 2. Left Sub 3. right (high and midrange) 4. Right Sub.

The advantage of this setup is that I can bypass the whole of the surround pre-amp and still get stereo subwoofer output when listening to music (have passive volume control on power amp for this purpose). Hope this post is not too confusing and helps you decide what is best solution for you.

Cheers,

Chris

[THOR]

I have been running stereo subs for over 6 years and would never again run just 1. Because of the very long wavelength of bass, 2 subs reasonably close together 10/15' will act like a line source . its subtle, but IMHO, time alignment with the mains helps integration at the XO freq. the subs dont have to be in the same part of the room, just the same distance away from ur ears. If the subs are good enough and the XO low enough to not be able to locate the position of the subs, they can be placed anywhere in the room that they sound best, as long as they are the same distance as the mains .

[johninCR]

Thor brought up what I think would be the justification for stereo subs and that is for integration with the mains in a stereo setup. In a 5.1 setup though and playing 5.1 material though there would be no benefit, since it's not 5.2 material. Equal distance to your ears of subs and mains isn't an issue as long as your receiver has settings for distance to the different speakers to align them time wise.

Thor,
I would think stereo subs acting as a line source would be problematic in that at say a 4 meter listening distance material where the subs play the same exact notes would be 6db louder than stereo sounds just because of the line array effect.

[chirotude]

Thanks for reply. What started my question is that I have everthing I need to make two exact subs with amps. I realize this does necessarily mean its the best choice. I want to get the most quality and quanity out of what I have. The alternative being spend more money on other ideas and feel the wrath of wife. I suppose I could build them if they work great ok, if not sell and start over. All thoughts on the matter, opinion or fact, help me to learn a little more. Thanks again

Doc

[johninCR]

Use both amps and drivers. Mount them in a 2 driver manifold to greatly cancel out mechanical vibrations. Put them in a push/pull alignment in an infinite baffle hidden up above your drop ceiling to maximise your sound quality and give you great WAF.