vasubandu Posted January 4, 2018 Share Posted January 4, 2018 In the SVS discussion area a guiy asked Can you speak to whether it would be possible to run dual subs, one PB-13 Ultra and the other a PB-12 Ultra? I imagine the subs have similar performance and phase response, however I'm not certain. For what it's worth, my room is large and open. It's about 15' x 22' x 15' with one of the 22' sides mostly open. Ed's answer was interesting. Yes, the PB13-Ultra and PB12-Ultra have similar FR and phase response and will work fine together. But before you place them in their intended locations, place them side-by-side with the phase controls set to 0 and then individually level match them using the AVR rumble tone, and then turn them both on together. The combined SPL should increase 4-5 dB over a single subwoofer. If the combined SPL obviously drops 8-10 dB, remove the BASH amp from the PB12-Ultra and reverse the electrical polarity of the woofer wires running to the amp (this is easy - they should both be 0.187 female spades). I always recommend this sanity check when mixing two subwoofers from different generations with different amp platforms. If you don't make sure they are the same electrical polarity, you'll be chasing your tail during set-up. Is this news to you guys or just par for the course? I only have one sub now, but am saving this for when I get a second. Quote Link to comment Share on other sites More sharing options...
Paducah Home Theater Posted January 4, 2018 Share Posted January 4, 2018 Most people who use multiple subs that are different or located around the room will have a capable external DSP that ought to be able to fix this with software. I can do this with a click of a button. Short of that yeah it's probably a good idea. DSP's introduce different delays and the difference could potentially be bad enough for two subs to partially cancel each other out. Quote Link to comment Share on other sites More sharing options...
DrWho Posted January 4, 2018 Share Posted January 4, 2018 Sounds like they discovered a polarity problem in production, that they fixed at a later date....but he didn't want to come right out and say it 1 Quote Link to comment Share on other sites More sharing options...
vasubandu Posted January 5, 2018 Author Share Posted January 5, 2018 Well as I see it, that would be easy to check and if it worked, then great. It does seem odd that they might be shipping with different polarities even in different models. And thanks guys for the insights. Quote Link to comment Share on other sites More sharing options...
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