Dual sub calibration for room mode control?

[yepimonfire]

Im planning on placing them in two opposite corners of the room to help cancel standing waves. Should i time align them by inverting the phase on the rear sub or would i get better results leaving them both the same?

My thinking is that leaving them at the same polarity will cancel out the rear wall reflections, vs reinforcing them, at the expense of spl of course.

Any thoughts?

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[TheWarrior]

Im planning on placing them in two opposite corners of the room to help cancel standing waves. Should i time align them by inverting the phase on the rear sub or would i get better results leaving them both the same?

My thinking is that leaving them at the same polarity will cancel out the rear wall reflections, vs reinforcing them, at the expense of spl of course.

Any thoughts?

Sent from my LM-X210(G) using Tapatalk

Dude, SPL is not going to be an issue, lol! Yes, keep the phase the same until your measurements tell you to change it. What you need to do is put on your critical listening ears and a familiar musical bass/drum riff and ensure both subs are playing in unison. If the beat of the music is not tight, you need to turn your head or stand up and figure out which sub is playing first, and then keep adding a millisecond delay to that sub until they both 'play in time'.

And before you ask, length of the cables is not the only cause for concern about setting the delay. The other issue is the control the room has over the distribution of high pressure areas in the room. Yes this can be influenced with where you place the subs, but the length of time it takes to propagate large wavelengths that are audible at a specific place in the room varies a lot more than people seem to realize!

Good luck!

 

[KEW]

And before you ask, length of the cables is not the only cause for concern about setting the delay.

Good luck!

At the speed of electricity, I have a hard time accepting the length of the cables is ever an issue for any normal residential scenario!

 

[shadyJ]

At the speed of electricity, I have a hard time accepting the length of the cables is ever an issue for any normal residential scenario!

The signal travels through the cable at something like 80% of the speed of light in a vacuum, so the speed of sound in a normal domestic environment is absolutely negligible in comparison. Cable lengths do not matter in this regard.

 

[shadyJ]

Im planning on placing them in two opposite corners of the room to help cancel standing waves. Should i time align them by inverting the phase on the rear sub or would i get better results leaving them both the same?

My thinking is that leaving them at the same polarity will cancel out the rear wall reflections, vs reinforcing them, at the expense of spl of course.

Any thoughts?

Sent from my LM-X210(G) using Tapatalk

You need to measure, and than make adjustments by trial by error through measuring. Anything else is just guesswork. All kinds of crazy things can happen with phase in-room.

 

[lsiberian]

The harman white paper actually suggests opposite midwall placement is optimal.

 

[yepimonfire]

The harman white paper actually suggests opposite midwall placement is optimal.

Unfortunately, the side and front midwalls are occupied with furniture.

I have three options, both in the corners at the rear wall (where the seating is located, or adjacent corners, front right corner and front left corner, or both in the right front and right rear corners.

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[yepimonfire]

Dude, SPL is not going to be an issue, lol! Yes, keep the phase the same until your measurements tell you to change it. What you need to do is put on your critical listening ears and a familiar musical bass/drum riff and ensure both subs are playing in unison. If the beat of the music is not tight, you need to turn your head or stand up and figure out which sub is playing first, and then keep adding a millisecond delay to that sub until they both 'play in time'.

And before you ask, length of the cables is not the only cause for concern about setting the delay. The other issue is the control the room has over the distribution of high pressure areas in the room. Yes this can be influenced with where you place the subs, but the length of time it takes to propagate large wavelengths that are audible at a specific place in the room varies a lot more than people seem to realize!

Good luck!

Yeah, audyssey usually sets my sub when located along the front wall at double the distance, I'm assuming this is because the LFs do a full 180 flip when they hit the rear wall and bounce back. The rules change when you get down that low.

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[TheWarrior]

At the speed of electricity, I have a hard time accepting the length of the cables is ever an issue for any normal residential scenario!

The issue is not electrical. The distribution of high and low pressure areas in the room is.

 

[TheWarrior]

Yeah, audyssey usually sets my sub when located along the front wall at double the distance, I'm assuming this is because the LFs do a full 180 flip when they hit the rear wall and bounce back. The rules change when you get down that low.

Sent from my LM-X210(G) using Tapatalk

Expanding on what I said to KEW, the issue becomes a balancing act of keeping your ears in a high pressure zone, as opposed to high particle velocity- common with uncontrolled reflections.

Simply put, this can result in a bass reproduction system that lacks tightness at all frequencies in its operating range. You don’t want some bass, you want it all. Drums can sound muddy, bass guitar exaggerated or notes may be missing.

That is the rooms influence and only the correct placement of ears and loudspeakers can overcome that influence. So get ready to take lots of measurements around your room!