My Listening Room
Old 13th March 2014
  #361
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Warmth

I am getting more into the notion that rooms treated extensively with fibre lack warmth, due to a 'sickout'. I have seen this repeatedly and am wondering as to the cause.
My Listening Room-screen-shot-2014-03-13-16.12.38.jpg

My Listening Room-screen-shot-2014-03-13-16.12.48.jpg

DD
Old 13th March 2014
  #362
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Quote:
Originally Posted by DanDan View Post
I am getting more into the notion that rooms treated extensively with fibre lack warmth, due to a 'sickout'. I have seen this repeatedly and am wondering as to the cause.
Attachment 388998

Attachment 388999

DD
Not sure what you mean or how your getting there. My 200hz data changes significantly if you move the LP and/or speaker positions. That is, the 200hz RT60 artifact is only true where things are positioned presently (or in specific areas). I can easily cure this phenomena, but other factors become much worse.

I dont know anything about fiber based treatment that would imply a specific attenuation at a particular frequency range when the density/thickness is sufficient to model as broadband.

Just today, I played with lowering the mic 4" and gained 2.5db at 200hz on the FR for instance.

My Listening Room-03-13-14-fr-r.jpg

My ceiling and side wall absorption models look like this Multi-layer Absorber Calculator
My Listening Room-18-fluffy.jpg
Old 13th March 2014
  #363
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Decay

FR will change radically over short distances, but decay times often do not.
My point here is that two different decay graphs show about half the length of decay at 200Hz compared to the surrounding frequency bands.
I have repeatedly noticed a very similar suckout in fibre treated rooms.
It is recurring enough to spike my curiosity, and it is not the partial resonance of 4" panels, which I suspected previously.
DD
Old 13th March 2014
  #364
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Anomaly

It is the anomaly I am interested in Jim, particularly as I have detected it in many of not most fibre treated rooms.
I stand by my point that FR will change radically with position while Decay times often will not change RADICALLY.
In some cases they may, but exceptions make the rule and in any case that hardly matters if one is interested in the anomaly I am pointing to. Even in this new graph of the other side of the room, the suckout remains quite noticeable. I find that interesting.

DD
Old 13th March 2014
  #365
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My Listening Room-03-13-14-r-lower-mic.jpg

03 13 14 IR R lower mic.wav

Apparently, the 200hz suckout isnt there on the Right channel even though the FR dip is similar. So you are right that FR and decay don't always correlate. But it would also seem to show that the room treatment isnt the cause.
Old 13th March 2014
  #366
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Quote:
Originally Posted by DanDan View Post
It is the anomaly I am interested in Jim, particularly as I have detected it in many of not most fibre treated rooms.
I stand by my point that FR will change radically with position while Decay times often will not change RADICALLY.
In some cases they may, but exceptions make the rule and in any case that hardly matters if one is interested in the anomaly I am pointing to. Even in this new graph of the other side of the room, the suckout remains quite noticeable. I find that interesting.

DD
Phase angle calculation time delay frequency calculate phase lag difference time of arrival ITD oscilloscope formula angle current voltage phi phase shift time difference - sengpielaudio Sengpiel Berlin

My Listening Room-200hz-floor-bounce.jpg

As to what you observe, and I have also, I think (speculate) that floor bounce maybe key. Using the calculator link, one will find that typical floor bounce delays (2-3ms) correspond to (167hz - 250hz) out of phase.

I would further speculate that this turns up in treated rooms more than others because reinforcing (in phase) sidewall and ceiling reflections are minimized (absorbed) to a greater degree than floor reflections.
Old 13th March 2014
  #367
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Quote:
Originally Posted by jim1961 View Post
Phase angle calculation time delay frequency calculate phase lag difference time of arrival ITD oscilloscope formula angle current voltage phi phase shift time difference - sengpielaudio Sengpiel Berlin

Attachment 389047

As to what you observe, and I have also, I think (speculate) that floor bounce maybe key. Using the calculator link, one will find that typical floor bounce delays (2-3ms) correspond to (167hz - 250hz) out of phase.

I would further speculate that this turns up in treated rooms more than others because reinforcing (in phase) sidewall and ceiling reflections are minimized (absorbed) to a greater degree than floor reflections.
Room Acoustics

Correct AFR, Density and Thickness for SuperChuncks Corner Traps relation

Old 13th March 2014
  #368
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Old 18th March 2014
  #369
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Old 18th March 2014
  #370
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My Listening Room-3-17-14-fr-2.jpg

My latest point of interest is channel response deviation. Anyone know how much is acceptable, good or bad? Do some areas of frequency get treated different (in terms of allowable deviation) than others?
Old 18th March 2014
  #371
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Perfect

There is another thread running on Mild Hearing Loss and whether to Eq for it or not. Makes sense to include that physical link in the chain IMO. Must try it soon. There is considerable divergence between my ears at HF. Even visibly one is at a quite different angle to the other.....;-)
I suspect I may have never actually heard true stereo.
DD
Old 18th March 2014
  #372
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Old 18th March 2014
  #373
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Quote:
Originally Posted by jim1961 View Post
Attachment 388459

Here is one from last month for the left channel. Keep in mind, this is a snapshot (one short sine sweep) as it is made in Omnimic. Noise pretty much makes anything below -35db on the waterfall useless.
That is a fun little REW file to look at. The ETC is interesting.
I would love to hear your room some day.
Old 18th March 2014
  #374
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Quote:
Originally Posted by Glenn Kuras View Post
That is a fun little REW file to look at. The ETC is interesting.
I would love to hear your room some day.
Ever in Texas?
Old 19th March 2014
  #375
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Quote:
Originally Posted by jim1961 View Post
Ever in Texas?
My wife is from TX so we visit Austin and Brownwood a lot.. Sometimes make it up to Dallas.
What parts of TX are you'll in?
Old 19th March 2014
  #376
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Quote:
Originally Posted by Glenn Kuras View Post
My wife is from TX so we visit Austin and Brownwood a lot.. Sometimes make it up to Dallas.
What parts of TX are you'll in?
Dublin.

2.5 hours from Dallas and Austin
1 hour from Brownwood

You would go right by me driving from Brownwood to Dallas.

What kind of music do you like to listen to?
Old 19th March 2014
  #377
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Quote:
Originally Posted by jim1961 View Post
Dublin.

2.5 hours from Dallas and Austin
1 hour from Brownwood

You would go right by me driving from Brownwood to Dallas.

What kind of music do you like to listen to?
I have been to Dublin!! Last time we drove through Dublin, they had some horse thing going on. Looked like some kind of cattle drive.
Next time I am in Brownwood I will contact you.
Old 19th March 2014
  #378
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Originally Posted by Glenn Kuras View Post
I have been to Dublin!! Last time we drove through Dublin, they had some horse thing going on. Looked like some kind of cattle drive.
Next time I am in Brownwood I will contact you.
Excellent!

It would be nice to have a outside opinion of my work. Look forward to it
Old 7th April 2014
  #379
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My Listening Room-100-0078_img.jpg


My Listening Room-04-07-14-etc-r-l.jpg
Orange = Right
Grey = Left
No smoothing, full range

(ignore blue line at top and reflections at 37ms. The later are blocked when one is actually sitting at the LP)


Been working on my tail (not to be confused with problems sitting)

The top image shows how I staggered the reflection panels into 3 tiers rather than the previous two. It has the effect of smoothing out the reflections temporally and extending them slightly further from the terminator.
Quote
2
Old 19th April 2014
  #380
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It never ends.....

My Listening Room-03-17-14-vs-now-fr-r-mm.jpg

Red = Now
Blue = Before (my last post on 03 17)

Getting that 150hz- 225hz area right has been the hardest and most time consuming task period in this whole treatment endeavor. Anybody ever heard the saying "The 50th try is the charm"? Pretty close now. Backed off on the 20hz - 40hz area a bit as well.

My Listening Room-04-19-14-l-r-mm-both-fr.jpg

Gray = Left
Red = Right
Green = L + R

(all graphs 1/24th smoothing, 250ms gate)
(mic pointed strait ahead)


For those just tuning into this thread at this point, these readings are WITHOUT any processing what so ever. NO EQ, NO DSP, NO Audyssey.
Old 19th April 2014
  #381
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Does your graph change by a couple of dB if you move your mic a few inches left, right, front or back?
Old 20th April 2014
  #382
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Originally Posted by seiyafan View Post
Does your graph change by a couple of dB if you move your mic a few inches left, right, front or back?
Yes. Further back in this thread are examples of that.
Old 20th April 2014
  #383
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Quote:
Originally Posted by jim1961 View Post
Yes. Further back in this thread are examples of that.
The reason I am asking this is because I am in the process of convert a bedroom in my house to a mini theater and I discovered how peaks and nulls could change a lot even if I move microphone several inches, now I can't freeze myself like a stick and not move my head an inche during a 2-hour movie, not to mention my ears are separated by 10 inches.
Old 20th April 2014
  #384
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Quote:
Originally Posted by seiyafan View Post
The reason I am asking this is because I am in the process of convert a bedroom in my house to a mini theater and I discovered how peaks and nulls could change a lot even if I move microphone several inches, now I can't freeze myself like a stick and not move my head an inche during a 2-hour movie, not to mention my ears are separated by 10 inches.
Some chairs are such that they suck you into one place when you sit in them. Its surprising how close your ears end up in the same place every time in such a situation.
Old 28th July 2014
  #385
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You make me sick!


lol, gonna be in the NorthEast anytime soon? You sir, are the quintessential perfectionist!
Old 28th July 2014
  #386
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Quote:
Originally Posted by AwwDeOhh View Post
You make me sick!


lol, gonna be in the NorthEast anytime soon? You sir, are the quintessential perfectionist!
Thanks, well, I dont like making my readers sick of course

In reality, I do not know if my results are attributable to luck or skill. And frankly, I still see many imperfections.

Sorry, I dont get to your part of the woods.
Old 4 Weeks Ago
  #387
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Quote:
Originally Posted by jim1961 View Post
Thanks, well, I dont like making my readers sick of course
in a good way

Quote:
Sorry, I dont get to your part of the woods.
lol, ok, i'm moving!

Quote:
In reality, I do not know if my results are attributable to luck or skill. And frankly, I still see many imperfections.
[luck or skill] or free time?
Only a true perfectionist would only sees the imperfections!

I admire your quest [OCD?] for the perfect listening room.
Old 1 Week Ago
  #388
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My Listening Room-fr-today.jpg

(1/24th octave smoothing applied)

My mains (black) are quite capable of good response below 45hz, but the room null starts there and down to about 30hz. Sub1 (blue) primarily I use to fill the gap so speak. Sub2 (purple) for just a tad more smoothing resulting in the composite or overall graph (green).

These are all measurements at the listening position.

Just documenting my low end (left channel) measurements.
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Old 1 Week Ago
  #389
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Looks great.
Old 6 Days Ago
  #390
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When using 2 subwoofers, is it better to drive each sub with both channels of the amp, or to hook up one sub to the right channel & the other to the left channel?
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