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[Steve-White]

Polarity not phase.

Ultimately, if you can't troubleshoot the problem, and reversing the polarity on one sub cures it, just do it.

Being an electrician, that leaks out from time to time.  Ok, polarity which could be manifesting as a phase issue in this case. 

I would definitely want to know what the problem was, especially if it's a cable as that could cause some real brain drain if it got moved around in the system.

[Art Welter]

Hi, I have a system composed of 4 electrovoics and 2 Horn Fold subwoofers. The problem is that the crossover is canceled between it is dbx 223XL and I noticed that I always have to press the reverse button on the right side to sound properly. Both are in the phase, I noticed that the bass feels strong in the middle and not at all in the corners, instead if you press the reverse button in the corners it sounds like full bass. Finally the bass where it should feel in the middle or in the distance ??

John,

Sounds like room modes along with time-of flight phase alignment issues. Neither will be fixed with a polarity reverse, which will just move the problem around the room.

[Steve-White]

John, I assumed you were just inverting the phase on the right channel LF output to the subwoofer.  Correct?

https://dbxpro.com/en/product_documents/dbx223234xlmanuala2pdf

Mac, Riley and I are on the same page with regard to troubleshooting your system.

Art makes a good point too, it may be the room.

[John Brad]

so in the end everything is fine, where do you have to feel the bass in the middle or in the back?

[Tim McCulloch]

so in the end everything is fine, where do you have to feel the bass in the middle or in the back?

Back to front is a matter of spacing - the distance from the subs to the nearest large, reflective thing behind them (say, a wall) and the boundary at the opposite end... AND the frequency in question because it's all about wavelengths.

Now repeat that for side to side and you can "see" where perceived position of LF/ELF will change based on your location in the sound field and with changes in frequency.

This is all about reflections, standing waves and room modes.  If you want to hear what 1 sub (or 1 stack of subs) sounds like, take it outdoors where you've got a one hundred foot radius free of reflections (buildings, wall, trucks or autos) and make some noise - tones, sweeps, pink noise - and walk all around the sub at various distances.  Now add another sub / stack of subs some distance away and repeat your signals and walks.  You're hearing the result of physics, and as Scotty told Kirk, "Captain, I canna change the laws of physics!"

The result is getting to pick which of several compromises work best, with the equipment at hand, in the places you are able to deploy your subs/tops.

Indoors?  It's all a crap shoot.  In the end one must accept that there will be places in the room where the results will sound/feel different than a spot only a meter away.

[Brian Jojade]

Indoors?  It's all a crap shoot.  In the end one must accept that there will be places in the room where the results will sound/feel different than a spot only a meter away.

Not quite a complete crap shoot, but certainly close.  With enough detail, you can calculate and predict how things will play out, but yeah, getting 100% even coverage indoors is next to impossible.  With proper placement, you can usually achieve decent sound in the areas that matter.  But, as you stated, sometimes proper placement too has to be compromised, as something else may need to be in place of where that speaker sits.

For small venues, this is where experience kicks in more than anything. It's not practical to model each and every room, and different things like wall materials, ceiling patterns, etc make that nearly impossible.  Intuitively knowing that moving a sub a couple feet one way or another can change the sound dramatically is something that can be learned over time so that when you walk into a room you can drop speakers in locations that will give you 'good enough' results.

[ProSoundWeb Community]