Early sidewall reflections

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abomwell

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Early sidewall reflections
« on: 22 Dec 2021, 01:54 pm »
 Everyone here knows that dipoles create a null on the speaker's lateral (and vertical) axis. This morning I experimented by using a hand mirror placed on the left sidewall to find the left speaker's reflection point as seen from the listening chair. And then, with very slight additional toe in, I was able to only see the speaker's edge in the mirror. I repeated that on the right wall. The resulting toe-in aimed the speakers just outside my ears. The toe-in adjustment points the speakers' null at the first sidewall reflection point all but eliminating it without needing padding placed there. The speakers and chair are located in an 8' equilateral triangle configuration.

About a week ago, with the listening chair back about 8", I noticed that when I leaned inward towards the speakers by about 8" I heard a clearer presentation. As a result I moved my chair up 8" and have liked the cleaner sound from that location. As it turns out, by changing the chair's location,  I inadvertently placed it where the early reflections were greatly mitigated by the speaker's lateral null. If you can manage doing this you might find it helpful too.

mrotino332

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Re: Early sidewall reflections
« Reply #1 on: 22 Dec 2021, 02:53 pm »
My X5s are about 7 and half feet apart and only about 18 inches from the side walls and I sit about 8 and half feet away.  I've actually experimented with treatments at the first reflection point using a mirror and I don't hear a difference with or without the treatment.  Honestly I don't hear much sound when I put my ears at the first reflection point as the null is to the sides and most likely also because my side walls are fairly close to the speakers.  So I'm currently using no treatment at the first reflection point but do use treatment at the second reflection point.  The second reflection point is when you use a mirror on the side wall and see the opposite speaker in the mirror.  There is a lot of sound output at the second reflection point and my room is long and narrow so I do notice an improvement with room treatment at the second reflection point.

rooze

Re: Early sidewall reflections
« Reply #2 on: 22 Dec 2021, 03:18 pm »
The speakers and chair are located in an 8' equilateral triangle configuration.

Curious to know how far you have the speakers from the front wall in this 8' configuration.

abomwell

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Re: Early sidewall reflections
« Reply #3 on: 22 Dec 2021, 03:33 pm »
Curious to know how far you have the speakers from the front wall in this 8' configuration.

Speakers are 53" from front wall which is 29% of the room's length. According to Art Noxon, owner of ASC, that is where he recommends placing a subwoofer for room's length. He also recommends 29% of room's width which is not necessary for dipoles, and 29% of room's height which obviously won't work.

DBT AUDIO

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Re: Early sidewall reflections
« Reply #4 on: 23 Dec 2021, 06:55 am »
Everyone here knows that dipoles create a null on the speaker's lateral (and vertical) axis. This morning I experimented by using a hand mirror placed on the left sidewall to find the left speaker's reflection point as seen from the listening chair. And then, with very slight additional toe in, I was able to only see the speaker's edge in the mirror. I repeated that on the right wall. The resulting toe-in aimed the speakers just outside my ears. The toe-in adjustment points the speakers' null at the first sidewall reflection point all but eliminating it without needing padding placed there. The speakers and chair are located in an 8' equilateral triangle configuration.

About a week ago, with the listening chair back about 8", I noticed that when I leaned inward towards the speakers by about 8" I heard a clearer presentation. As a result I moved my chair up 8" and have liked the cleaner sound from that location. As it turns out, by changing the chair's location,  I inadvertently placed it where the early reflections were greatly mitigated by the speaker's lateral null. If you can manage doing this you might find it helpful too.
Good information!!  You mentioned your speakers were positioned 53" from the front wall.  Does the music sound like it's coming from behind the speakers?  I'm curious because I like that type of presentation from speakers.  I'm not in a position to have my speakers that far out from the front wall in my current room.

abomwell

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Re: Early sidewall reflections
« Reply #5 on: 23 Dec 2021, 10:28 am »
Yes, it does seem as though the music is coming from behind the plane of the speakers. I have noticed that the farther away from the front wall speakers are positioned the more apparent the depth. In my experience that has been true with all speakers, monopoles, dipoles and omnis.

This evening I remeasured the speakers and allowed my Anti-mode X4 to recalculate the room correction.  I was pleasantly surprised that there was very little to correct! Anti-mode shows a measurement with the corrected curve superimposed over it. It pulled down a room mode peak at 40dB about -3dB and made an additional three other small changes. When I toggled the corrected curve and the uncorrected curve, in bypass mode, the difference in sound was almost indistinguishable!! I manually brought down a small peak centered at 2kHz that was also present and the resulting frequency response is very flat with a slight, (and desirable) rising slope in the bass and a gradual downward slope above 2kHz.

This afternoon a good friend, who had been the principal trombonist in the LA Philharmonic for over 30 years, came over to listen. We played several recordings including some LA Phil ones that he was playing on. He was quite impressed and very complimentary of the X5's. Interestingly, most musicians I've ever known are unimpressed with audio systems and have some of the crappiest playback equipment out there. That my friend was impressed is really a big deal and says a lot about the X5's!

DBT AUDIO

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Re: Early sidewall reflections
« Reply #6 on: 25 Dec 2021, 09:51 pm »
Yes, it does seem as though the music is coming from behind the plane of the speakers. I have noticed that the farther away from the front wall speakers are positioned the more apparent the depth. In my experience that has been true with all speakers, monopoles, dipoles and omnis.

I have a pair of KEF LS50 speakers in a second system and they have a nice soundstage behind the speakers as they are over 3’ or more off the front wall.  I plan to pull my X5s off the front wall when I have more space in a different room.  Its a good confirmation that your system is dialed in when you receive a positive review from your friend who’s been a member of the prestigious LA Philharmonic.  I imagine musicians would compare speakers to live instruments vs. comparing speakers to other speakers.

abomwell

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Re: Early sidewall reflections
« Reply #7 on: 25 Dec 2021, 10:47 pm »
I have a pair of KEF LS50 speakers in a second system and they have a nice soundstage behind the speakers as they are over 3’ or more off the front wall.  I plan to pull my X5s off the front wall when I have more space in a different room.  Its a good confirmation that your system is dialed in when you receive a positive review from your friend who’s been a member of the prestigious LA Philharmonic.  I imagine musicians would compare speakers to live instruments vs. comparing speakers to other speakers.

I think it's difficult for him to get excited about audio after sitting in a live orchestra several hours daily for decades. But he will say something like "Yup, that's what a piano sounds like on stage".  I think a reason why musicians seldom are audiophiles is that they "fill in" from their aural memory what's missing, and ignore what's been added, from distortion, to what they hear in audio. So in a sense they can "listen through" the sound to what they hear in their mind.


Wayner

Re: Early sidewall reflections
« Reply #8 on: 25 Dec 2021, 11:31 pm »
I have ML reQuests that are dipole. lots of music comes from behind the speaker to the front wall and that will hit the side wall too. I suggest finding the hot spot on the front wall and where that translates to the side wall (I'm sure it will be close to the corner). The corner may make a mid/bass hump.