Ron’s New System

[Ron Resnick]

Thank you Ron. I like the one from February.

I do too. The video from February sounds the most "alive."

But this, in my view, is the potentially insidiously misleading nature of videos. In the room, in person, to my ears, yesterday's Soular Energy playback sounded more natural and more realistic than it did in February.

The only difference is the four absorption panels on the front wall. The interesting test, to me, is if you would prefer in the room, in person, to your ears, the sound with the absorption panels (presently) or without the absorption panels (February).

 

[Ron Resnick]

Hi Ron,

Of those three audio clips… which one do you like the most? Which is ofcourse IMO the most important part.. as it is your room?.

/ Jk

It's really the February sound versus yesterday's sound (I aggregate yesterday's two videos together) .

The video from February sounds the most "alive."

But I'm not trying to solve for the frequency response and the acoustic treatment arrangement which makes videos sound natural. I'm trying to solve for the frequency response and the acoustic treatment arrangement which makes music in the room sound natural.

In the room the sound in February was a little bit unnaturally bright. I felt there was a little bit too much upper midrange energy. Maybe I simply don't know how piano sounds in person, but I felt that the piano sounded a bit too tinkly and a bit too bright.

If a professional pianist came over and selected one acoustic treatment arrangement over the other to achieve whichever frequency response sounded the most natural to him/her on piano, I would stay with that arrangement.

It's complicated because there are other factors. I will be switching from my universally derided DIY Sorbothane amp stands to Adona Zero GTX1N amp stands. I think literally everybody warned that Sorbothane amp stands will dampen/soften/slow down the sound.

Will this switch from DIY Sorbothane amp stands to commercial amp stands have the effect of making the overall presentation a bit more lively? Without the absorption panels might that amp stand swap make the sound too bright?

More experimentation is required. Removing or placing the four absorption panels on the front wall takes about three minutes, and it takes that long only because I have to be careful not to trip over all of the cables. Once the new amp stands are in place, I will have to reevaluate the sound.

Another factor, of course, is the recording itself. On brighter recordings the absorption panels may make the frequency response overall more natural. So acoustic treatment cannot be set merely to optimize naturalness on one recording.

For example, Fleetwood Mac's "The Chain" definitely sounds better to me now than it did in February. And I do not think of that track as a "bright" recording.

Another factor, of course, is personal preference. The very recordings from which Don and I heard too much upper midrange energy on piano sounded just right to other visitors.

 

[Ron Resnick]

My suspicion based on pjwd's analysis and on two evenings' worth of listening is that I overshot the mark with these four absorption panels by absorbing a little bit too much above 1000 Hz and by not focusing on minimizing absorption below 1000 Hz. I'm going to narrow (30" --> 24") and thin out (1" --> 1/2") the panels, and run the frequency response test again, and evaluate my personal happiness with the sound.

At that point I likely will leave it there -- and just swap the amp stands when I can figure out how and with whom to lift up the 200 pound amps -- until and unless friends and visitors report frequency response issues with which I agree.

 

[PeterA]

I do too. The video from February sounds the most "alive."

But this, in my view, is the potentially insidiously misleading nature of videos. In the room, in person, to my ears, yesterday's Soular Energy playback sounded more natural and more realistic than it did in February.

The only difference is the four absorption panels on the front wall. The interesting test, to me, is if you would prefer in the room, in person, to your ears, the sound with the absorption panels (presently) or without the absorption panels (February).

Yes of course, the in room assessment has more value than a video assessment from a far. Also, clearly your opinion and preference matters much more than mine to you. In the end it’s all about what you think of your system in your room. This is why I think a written description from the listener about the differences between what he hears in the room and what he hears from the video helps in the assessment of the quality of the video.

For me, the absorption panels are not simply to shift frequency response as heard and as reflected in the measurements. It’s also about what the panels do to the information on the recording as it is presented in the room. A big part of live sound and natural sound, for me at least, is the sense of nuance and ambience one experiences when listening. The balance between what is emphasized and what is not. If treatments or other audiophile accessories strip out or alternate that balance in the presentation, the sound becomes less natural, less convincing, and less like the real thing.

I don’t know what your system sounds like in the room, I am only expressing my preference between the videos. Thank you for posting them. They are consistent with the impression I had of your other video which was a very different recording.

 

[Ron Resnick]

For me, the absorption panels are not simply to shift frequency response as heard and as reflected in the measurements. It’s also about what the panels do to the information on the recording as it is presented in the room. A big part of live sound and natural sound, for me at least, is the sense of nuance and ambience one experiences when listening. The balance between what is emphasized and what is not. If treatments or other audiophile accessories strip out or alternate that balance in the presentation, the sound becomes less natural, less convincing, and less like the real thing.

I don't understand this. The fact is that the absorption panels, above 1000Hz, are effecting a largely linear shift in frequency response. That is what they are doing, and that is all they are doing.

Whatever anomalies you are hearing have to be grounded in a largely linear shift in frequency response. It's not like the absorption panels are absorbing materially more at 1000Hz, less at 2000Hz, and more at 4000Hz. There is no random or irregular or unpredictable emphasis and spotlighting at certain frequencies and de-emphasis at other frequencies.

 

[PeterA]

I don't understand this. The fact is that the absorption panels, above 1000Hz, are effecting a largely linear shift in frequency response. That is what they are doing, and that is all they are doing.

Whatever anomalies you are hearing have to be grounded in a largely linear shift in frequency response. It's not like the absorption panels are absorbing materially more at 1000Hz, less at 2000Hz, and more at 4000Hz. There is no random or irregular or unpredictable emphasis and spotlighting at certain frequencies and de-emphasis at other frequencies.

Ron, I hear the effect of the panels in the videos. I disagree that all they are doing is shifting the frequency response as captured by your measurements. Let us agree to disagree. I am not capable of explaining this to you, and for that I apologize. I have tried in multiple private conversations and failed. I am very happy that you like the effect of those panels on the sound, and that you are enjoying the sound of your new system.

 

[Alrainbow]

Many think videos are useless lol and In many ways they might be.
But to someone who knows they can extract info and help. I too was shown and proved there use
lastly while room sweeps help they can be misleading and this cements our ability to be effective.
if I say the room is Brite and show you a scan does it make me correct ? Well maybe I’m deaf but I still planted a seed and it will effect your own observatory outcome at times.

 

[pjwd]

Ron I still suspect its the dip between 200 and 1000 hz that causing a comparative brightness above
A few more thoughts
At the crossover point of 250 the drivers should be closer than 1/4 wavelength to prevent lobing which is 344mm... it looks as though this is not the case .. also unless there is a digital delay in woofer tower drivers would not be time aligned .. woofer prob need to be 20 to 30mm forward of mid
Is there anyway to move woofer forward and closer ... what does Gryphon advise

Earlier Keith suggested speakers were not properly placed and as dip was not short and deep I did not think that was the case but it could be that there are multiple dips that are accumulative that sum to a long shallow dip.. this would be distances between roughly 150 and 300mm plus one wavelength ( 4 times those numbers) as your room is quite assymetrical it may be developing a broad range of different reflective distances.
I think you would do well to get in someone who can do a range of more sophisticated measurments and attempt to flatten out the response as much as possible by speaker and chair location and then decide if you need absorbtion.

Out of interest if you move mic closer to speakers does the dip flatten out

BTW a quick google image search does show some setups with woofer tower inboard which to me is very logical .. the dipole has little sideways energy and the woofer has decreasing directional information
Enough from me
Phil

 

[sbnx]

pjwd kindly wrote to me privately that "the dip in between 200 and 1000 is a bit deeper with the panels." I hadn't noticed this myself on the frequency response chart, but he is correct.

Ideally I don't want the absorption panels absorbing anything below 1,000Hz. But that is not the way absorption panels work. There is no electronic absorption slope control on an acoustic panel.

Switching from 1" thick panels to 1/2" thick panels will reduce slightly the absorption from 500Hz to 1,000Hz.

As I experiment with absorption panels of different dimensions and in different locations and in a different quantities I simply lean the panels up against the wall. I realized one additional thing myself: there is an air gap between panel and the wall. Leaning the panel against the wall, the top of the panel touches the wall, and the bottom of the panel touches the floor a few inches away from the wall. This air gap increases the absorption of frequencies below 1,000Hz.

Hello Ron,

I have posted a couple graphs showing the absorption of 1" rigid fiberglass vs 1" rigid fiberglass with a a 1" air gap behind it. We make a few observations based on these.

First, the 1" fiberglass mounted directly to the wall starts dropping rapidly at 3000 Hz and by the time it reaches 1000Hz is at 40% absorption. It is at 20% at 500Hz.

Second, the 1" fiberglass with the 1" airgap absobs a lot lower. It is still at 90% absorption at 1000Hz and at 45% at 500Hz. So the airgap is causing a lot more absorption than you might expect.

Third is that the absorption vs frequency is not quite linear just above the "knee". This is only a few percent and should not make that much of an audible difference. keeping in mind that everything matters. it is just to what degree it matters.

It depends on how tall the panels are but if you are resting them on the floor (propped against the wall) then that is not quite what you will get when you mount them up a little higher as that is going to affect the RT60 quite a bit more.

Frequency response if one thing. But I have found that as long as the frequency response is relatively smooth it is ok. (Meaning no 5-10 dB bumps at 60Hz or some other narrow frequency band). The graph that tells the story above the schroeder frequency is the RT60 vs frequency. As long as that graph is smooth the sound always sounds good. If there is a big peak at 300 Hz or 2000Hz or wherever then your ear will quickly pick that up and anything around that frequency will have a resonance too it that will become irritating very quickly. I wish you could get someone to measure your room with REW. Then you would be able to quickly assess what the panels are doing and also where best to put them. You can do this by ear but it just takes a little longer.

 

[Ron Resnick]

Out of interest if you move mic closer to speakers does the dip flatten out

As I move the microphone towards the speakers, the dip does not seem to flatten out, but the peak moves down and frequency from about 60 Hz to about 40 Hz.

 

[Ron Resnick]

So the airgap is causing a lot more absorption than you might expect.

Thank you for the information and your further analysis. I think that mounting the panels on the wall, and eliminating the air gap, might ameliorate some or most of the panel-related dip below 1,000Hz.

Also, the next set of panels will be 1/2" thick rather than 1" thick. This change will help to minimize absorption below 1,000Hz.

 

[pjwd]

As I move the microphone towards the speakers, the dip does not seem to flatten out, but the peak moves down and frequency from about 60 Hz to about 40 Hz.

Clearly the 40 -60hz shift is room mode but non moving dip suggests that proximity to side wall ( and perhaps low ceiling on one side) could be the problem .... if it is indeed cancelation from relection
Try measuring by moving side wall to side wall in a few spots to see if dip remains

 

[Ron Resnick]

what does Gryphon advise

Gryphon advises the towers to be on the radius of a circle, so each tower is equidistant to the listener.

 

[pjwd]

Gryphon advises the towers to be on the radius of a circle, so each tower is equidistant to the listener.

OK .. presume this creates necessary offset in drivers

 

[Blue58]

Hi Ron,
why are you not treating the upper part of the room? It’s as though there is an invisible ceiling that audio doesn’t break through.
in my small room the bass locked in once the upper half of the room was treated with bass traps.

I also fooled my bass units side wall reflection using a horizontally placed trap centred to the drivers.

cheers
Blue58

 

[Ron Resnick]

Hi Ron,
why are you not treating the upper part of the room? It’s as though there is an invisible ceiling that audio doesn’t break through.
in my small room the bass locked in once the upper half of the room was treated with bass traps.

Thank you for the suggestion!

I haven't focused on bass traps in the ceiling because I view those devices as broadband bass absorption, whereas I have two fairly sharp room node frequency spikes. My current thinking is that these two nodes are best addressed with higher Q solutions than broadband bass ceiling absorbers.

if Helmholtz resonators could be attached to the ceiling that could be a solution as well.

 

[Blue58]

Thank you for the suggestion!

I haven't focused on bass traps in the ceiling because I view those devices as broadband bass absorption, whereas I have two fairly sharp room node frequency spikes. My current thinking is that these two nodes are best addressed with higher Q solutions than broadband bass ceiling absorbers.

if Helmholtz resonators could be attached to the ceiling that could be a solution as well.

I wasn’t thinking of ceiling treatment rather the room corners in the upper half requiring the corner traps to reach to the ceiling.

I defer to the experts.

 

[Ron Resnick]

I wasn’t thinking of ceiling treatment rather the room corners in the upper half requiring the corner traps to reach to the ceiling.

Oh, actually I used to have floor-to-ceiling TubeTraps in both front corners.

 

[Ron Resnick]

I just re-measured the distance between the ribbon panels and the front wall. The whole set-up was cattywampus.

One panel was 1.5" further away from the front wall than the other panel. And neither panel was square to the front wall (both panels were off square by 1/2" with a bit of random toe-in).

When my patience tank refills I will check the distance between the woofer towers and the front wall.

 

[dan31]

Dog moved the towers.