L/R speaker delay

[thexder]

Okay, thank you. I wasn't sure about this but now you and John M. confirmed this.
Excellent!
Time to do some testing!

 

[thexder]

Okay, did some tests but nothing to show yet. I've been researching ETC and found out this (from acousticfrontiers.com):
‐ it is not necessary for the speakers to be placed exactly the same distance from the left and right side walls. In fact this approach can often lead to problems since the path length differences from each speaker to nearby boundaries are the same, causing speaker boundary interference related nulls to coincide

Wouldn't that be similar to delaying one of the speakers?

 

[JStewart]

Wouldn't that be similar to delaying one of the speakers?

Are you asking if delaying one of the speakers is similar to not having their distance from the side walls the same or are you asking if the principle of out of phase signals causing cancellations is the same?

 

[thexder]

First one - delaying vs. different distance from the side walls.

 

[JStewart]

I may still not understand your question and sorry if not, but here goes ...

In the case of not having speakers equidistant from side walls the author is pointing out that, assuming the listener remains equidistant from each speaker, by having a different path length difference between direct and reflected sound for each, there will be a different center frequency of the dip (out of phase cancellation) caused by each. Often, as in the example provided in your link, this occurs in the lower registers when both speakers can be playing the same frequency at the same time, so the listener will hear more of the intended sound as it's now being cancelled for just one of sources rather than both at the same time. So the author's intent was to point out one way to mitigate the negative effect of domestic room wall bounce caused phase cancellations that will exist.

In contrast, if starting with 2 equidistant speakers, by electronically delaying one speaker so the arrival time of the direct sound from each is longer equal, phase cancellation is being unnecessarily created (when both are playing the same frequency at the same time) along with other more noticeable unwanted effects.

Changing the arrival time of the direct sound through electonic delay also does nothing to change the frequency that will be affected by the wall bounce cancellations. The difference in path lengths of direct and reflected sounds remains the same.

 

[thexder]

Ok, thank you very much for your explanation. The assumption that the listener remains equidistant from each speaker cleared things out.
If the listener is at the center of two speakers and each speaker has different distance to sidewall this could minimize speaker boundary interference.
Am I getting this correctly?

 

[JStewart]

Yes but I’ll add for clarity that it can reduce the EFFECT. Boundary interference remains.

Here’s a website I think does a good job explaining SBIR and ways to deal with it. http://arqen.com/acoustics-101/speaker-placement-boundary-interference/

 

[thexder]

I agree, this is better explanation.
Thank you again!