Mastering Movie Audio for the Home - Page 19 - AVS Forum | Home Theater Discussions And Reviews
Forum Jump: 
 175Likes
Reply
 
Thread Tools
post #541 of 585 Old 06-19-2019, 03:45 AM
Senior Member
 
Join Date: Jan 2015
Posts: 264
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 178 Post(s)
Liked: 34
I also remembered a post I made some time ago quoting Tomlinson Holman and reposting it here @FilmMixer about the 83 vs 85 dBC controversy.
http://forums.musicplayer.com/ubbthr.../posts/1000723
Quote:
Thanks Jay for saying I'd work at the 1/100th of a dB level! But "Holmanism?" Ug. -18 dBFSrms = 85 dBC was not a Holmanism, but was SMPTE RP200 for years--but you had to read it carefully because it was buried in the text.

The fact is that -18dBFSrms instead of -20 dBFS was not a misprint. It was there to solve a problem and to make it so that 0 VU made 85 dBCslow. Please follow the history:

Dolby originally used a wideband (100 kHz) average responding HP400FL voltmeter to set the level of noise for the hundreds of generators that they built and supplied to technicians who in turn used them to set thousands of theaters.

This had three problems: the bandwidth of the noise they measured was far wider than the audio band, an average detector under-measures random noise by about 0.8 dB, and the time constant of the measurement was not long enough to promote good accuracy (this was the analog era; fancy add- 'em-all-up-across-the-file-length stuff didn't exist).

The added bandwidth had the effect of lowering the level in the audio band when you then actually did band limit, and thus to get back to the same level you had to turn it up.

The effect of using an average-responding detector instead of an rms one was to turn it up.

The effect of using a fairly short time constant was to make the reading difficult and unpredictable.

In contrast at Skywalker I used a Radford Audio Noisemeter ANM5 which had 1. a defined bandwidth corresponding to the audio band (DIN Audio Band 22 Hz - 22 kHz -3 dB like an Audio Precision), 2. a true-rms detector (an Analog Devices chip), and 3. arbitrarily long time constant (just put a big, big cap on the Analog Devices chip smoothing port, so long as you are willing to wait for the answer). Then set it to Dolby internal bus level, 300 mVrms for the CN85 which today corresponds to -20 dBFSrms.

Now when the Wow! laser disc came out having pink noise at this level, we got a message from Roger Dressler at Dolby saying that our level was wrong. I checked the work others had done and found that our disc was correct to our method within 0.2 dB, and that the pink noise that Dolby had supplied for the Video Essentials laser disc was wrong in level and was not flat. I sent them a 5 page or so FAX regarding my history of measuring and specifying noise, dating to the time I was chief engineer at Advent in the '70's. I've got it somewhere; you'd find it amusing reading.

Time passed. We could never get agreement in SMPTE because practical people wanted 0 VU pink noise on the bus to be 85 dBC slow on the Radio Shack, and I wanted reference level (say +4 dBu) rms band-limited pink noise measured over a long interval to be 85 dBC slow.

The problem with this is that VU meters have a consistent error and are also inconsistent one to the next unless expensive, and many aren't. Radio Shack meters ain't bad, especially when calibrated, but the tolerances on their C weighting filter is pretty loose, leading to at least a +/-1 dB variation between them when they are set identical on tone.

All of the above went into specifying RP200, which once again, was written by Ioan, not me. The -18 dBFSrms noise is 85 dBCslow (meaning -20 dBFSrms is 83 dBCslow) because then 0 VU on the bus IS 85 dB on the Radio Shack! The two statements are the same thing. This is why you got good results with the Martinsound CheckMax, which we make, and yet the numbers sound different.

Now, RP200 is being revised. Dolby LA never agreed to it (get the irony), and they now use a band limiting filter, but still an average detector, and 1 minute+ averaging. So things are converging (over 15 years!). I recently took my pink noise card out there and as a courtesy to me they calibrated it to their standard, so we'd be alike, but note that their contemporary practice now uses most of the things I'd been complaining about years ago. So we are converging I think.

Former posts in this thread had some errors. Here are some replies:

1. We've been told to set the subwoofer level to +10 dB on a sound level meter. WRONG. Since the bandwidth is narrower than the whole spectrum, the actual level of the subwoofer measured on a Radio Shack is about +4 dB (exactly depends on its bandwidth). I wrote a whole Surround Pro article on this which should be archived.

2. There's a lot of stuff about the X curve. I disagree with Jay about moving the break frequency out to 4 kHz in a small room, and I believe that Ioan and I are in agreement to follow the standard for film material, which has an adjustment for room volume given as the number of seats. Small rooms such as 60 seat dub stages I set up typically flat to 2 kHz and then down about 1/2 of the X curve above there, thus -4 at 10 kHz and additional roll off beyond there. Also, the level of this smaller dub stage is set 2 dB below the level of the main 185,000 cu. ft. auditorium (Norris that many people in LA know from SMPTE spring seminars for years).

3. I agree you don't want an X curve for DVD-A material. In fact our Tesseract system includes a "film-video" switch which does the right thing; it switches in two different high frequency curves, one for X curve compatible film material and one for flat home monitoring compatiblity. Note that it is re-eq in Home THX that fixes the difference on Hollywood program material for the home; otherwise it is too bright.

Last edited by Optimus_Fine; 06-20-2019 at 12:55 PM.
Optimus_Fine is offline  
Sponsored Links
Advertisement
 
post #542 of 585 Old 06-19-2019, 03:34 PM
Senior Member
 
awediophile's Avatar
 
Join Date: Oct 2013
Posts: 409
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 295 Post(s)
Liked: 150
Quote:
Originally Posted by OBJECT View Post
awediophile, I still do not believe that you are having a speaker freq. response curve 6Hz to 22kHz +-0.0 dB even +-1.0 run through a dedicated FFT app. speakers at 4 m. distance, in a room which do not have a acoustic treatment. There does not even exist a loudspeaker capable of that.

I mighr have seen one in a anechoic chamber. It was a completely round speaker. That one did in that completely dead room a flat response as a measurement mic.

How did you capture this 6 Hz from the freq. response?

You use same DSP optimization as Bag End which goes to 8 Hz?
Is your room tuned to 6 Hz?
My UMIK-1 mic (plus built-in pre-amp) was calibrated to 5 Hz by Cross Spectrum Lab.

I'm not sure what you mean here by speaker "freq. response curve". Frequency response curve for what? Measured where? Measured how? Analyzed how? What kind of smoothing is applied? What smoothing kernel? To which particular data? Different answers to these questions lead to different "frequency response" curves.

I don't optimize my spectral balance based on RTA measurements or any sort of "frequency response" curve, except (indirectly) anechoic chamber response, which I estimate from in-room data. Most curves obtained from in-room measurements are very strongly influenced by reflections and acoustic phenomena that are local to the measurement area. Attempting to "correct" either of these types of features using DSP provides no audible benefit and creates new audible flaws in the sound. EQing to make RTA bins or "frequency response" curves fit a target will inadvertently do this to some degree or another depending on the specific EQ strategy.

My approach is to move beyond the traditional paradigm of methods that fit "frequency response" to some target curve. My approach focuses on the response of each speaker in a global sense, which is closer to how I believe listener perception actually works. Human listeners are sophisticated, capable of not only adapting to most reflections and local acoustic phenomena but also using information from earlier reflections (usually radiated from the speaker at off-axis angles, for better or worse) to actually improve the quality of perception. Note that by "speaker", I include any bass-managed subs and potential active ambiance sources. If optimized successfully, these additional acoustic sources will seamlessly contribute to the perceived sound of the primary source.

I don't want to go into more detail here about my methods because it's off-topic, because it gets very technical, because I want to maintain some propriety for now, and because the technology is not available to the public and won't be until I'm able to do a lot more testing and validation.
awediophile is offline  
post #543 of 585 Old 06-19-2019, 11:34 PM
AVS Forum Addicted Member
 
Roger Dressler's Avatar
 
Join Date: Jul 2000
Location: Oregon
Posts: 11,478
Mentioned: 91 Post(s)
Tagged: 0 Thread(s)
Quoted: 2948 Post(s)
Liked: 1694
Quote:
Originally Posted by awediophile View Post
Pink noise that is band-limited to 500-2000 Hz is used to calibrate levels for music (see e.g. Bob Katz K-system), TV program in both US and Europe (ATSC and EBU recommendations), and home theaters (I believe originally recommended by THX).


Quote:
Out of curiosity, I measured the "full-band Dolby Pink Noise" sample as-is on my front-stage speakers with a calibrated Galaxy Pro SPL meter set to "slow". I get very close to 85 dBC at "0". Note that this test sample is actually around -18.2 dBFS:rms, so if -20 dBFS:rms is the standard that counts, then I may be technically a bit under "reference" at "0".
You are calibrated correctly. The pink noise standard used by Dolby these many years, and now codified in SMPTE 2095, reads -18.5 dBC. The reason is that when SMPTE defined their -20 dBFS spec, it was measured a) with an average responding meter, and b) in a bandwidth of 22 Hz to 22 kHz. Today we measure this noise with RMS meters (adding ~1 dB), over the full bandwidth of the signal, which extends down to 10 Hz.

Quote:
OTOH, if one first processes this pink noise sample using the X-curve target, it comes out exactly to -20 dBFS:rms. (This may be purely a coincidence.)
It's a coinkydinky, as they say.

Deadwood II Theater (Previous Deadwood Theater HTOM)
Anthem AVM 60 7.4.4; Classé SSP-800 PLIIx 7.4; MiniDSP OpenDRC-AN
Oppo UDP-203; Oppo BDP-93; Win7 media PC w/Roon+Kodi; Roku Ultra; DirecTV Genie
Adam Audio S3V/S3H LCR, KEF Ci200QS 4 srrnd, Tannoy Di6 DC 4 hts, Hsu ULS-15 4 subs
JVC RS520; Stewart Cima Neve screen 125" diag 2.35:1, MLP at 115"
Roger Dressler is offline  
Sponsored Links
Advertisement
 
post #544 of 585 Old 06-19-2019, 11:39 PM
AVS Forum Addicted Member
 
Roger Dressler's Avatar
 
Join Date: Jul 2000
Location: Oregon
Posts: 11,478
Mentioned: 91 Post(s)
Tagged: 0 Thread(s)
Quoted: 2948 Post(s)
Liked: 1694
Quote:
Originally Posted by Optimus_Fine View Post
So, if one wants to calibrate with a band-limited pink noise, from 625-2500 Hz, at -20 dBFS RMS, he should not actually aim for 83 dBC, but 84 dBC.
The "THX-style" bandlimited pink noise signal is derived via 4th-order high pass and 4th order low pass filter applied to the wideband pink source. The result is gain corrected to hit -30 dBFS:RMS (for a 75 dB SPL).

Deadwood II Theater (Previous Deadwood Theater HTOM)
Anthem AVM 60 7.4.4; Classé SSP-800 PLIIx 7.4; MiniDSP OpenDRC-AN
Oppo UDP-203; Oppo BDP-93; Win7 media PC w/Roon+Kodi; Roku Ultra; DirecTV Genie
Adam Audio S3V/S3H LCR, KEF Ci200QS 4 srrnd, Tannoy Di6 DC 4 hts, Hsu ULS-15 4 subs
JVC RS520; Stewart Cima Neve screen 125" diag 2.35:1, MLP at 115"
Roger Dressler is offline  
post #545 of 585 Old 06-20-2019, 03:24 AM
Senior Member
 
Join Date: Jan 2015
Posts: 264
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 178 Post(s)
Liked: 34
Quote:
Originally Posted by Roger Dressler View Post
The "THX-style" bandlimited pink noise signal is derived via 4th-order high pass and 4th order low pass filter applied to the wideband pink source. The result is gain corrected to hit -30 dBFS:RMS (for a 75 dB SPL).
Hi, Roger.

In a large room cinema, is the frequency response arriving at the listening position supposed to follow the X-Curve or is the X-Curve a method to obtain a flat frequency response in such environments?

If the former is correct, wouldn't the pink noise have a slightly higher level in cinema rooms corrected with the small X-Curve?

And if I was able to record a wide band pink noise equalized like the X-Curve and play it in a small room, would that be an incorrect calibration method?

To record a THX compliant narrow band pink noise, do I filter with a 4th order high pass at 500 Hz and a 4th order low pass at 2000 Hz?

Are soundtracks with Dialnorm -27 supposed to be played at Reference or left attenuated -4dB by the decoder?

Thanks.
Optimus_Fine is offline  
post #546 of 585 Old 06-20-2019, 05:01 AM
Advanced Member
 
Tomas2's Avatar
 
Join Date: Jan 2017
Location: New Orleans
Posts: 740
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 459 Post(s)
Liked: 716
Quote:
Originally Posted by FilmMixer View Post
I’ve never mixed a film at anything by reference level.
When time permits can you further explain what you mean by this comment ? No matter how i read it, i have no clue what your trying to convey.

Quote:
....I don’t know any mixer that starts with a near field and pushes their stems up to match the attenuation of the monitor level.
That is not the objective of lowering ones (mix) speaker calibration target. The goal is to slightly elevate the overall program average volume, but no one is saying it should “match” the offset.

-Tomas

SAMSUNG QLED | ROTEL | MOREL | M&K | HAFLER | TECHNICS SP-25
Tomas2 is offline  
post #547 of 585 Old 06-20-2019, 06:21 AM
Senior Member
 
Join Date: Jan 2015
Posts: 264
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 178 Post(s)
Liked: 34
I remade from scratch my estimations of the spectral distribution of the broadband pink noise, this time with 10 points at the ISO octave center frequencies, from 31.5 Hz to 16 KHz.

The first batch is a sum energy of 85 dBZ corrected with the standard X-Curve (-3 dB/octave <63 Hz, -3 dB/octave >2000 Hz and -6 dB/octave >10 KHz):

71.9897000434 dBZ
75 dBZ
75 dBZ
75 dBZ
75 dBZ
75 dBZ
75 dBZ
71.9897000434 dBZ
68.9794000867 dBZ
63.8605664769 dBZ

Total dBZ energy: 83.62 dBZ.

Now, the second batch, corrected with C-weighting:

68.9794000868 dBC
74.1793017518 dBC
74.8281815844 dBC
74.9994248672 dBC
75.0325388774 dBC
75 dBC
74.8305784321 dBC
68.9794000868 dBC
62.9588001734 dBC
52.7211329538 dBC

Total dBC energy: 82.98 dBC (+2.02 dB gain/octave for 85 dBC).

As can be noticed, the broadband pink noise adjusted with the X-Curve, when measured with C-weighting, has a measurement error of only -0.64 dB.

Now, the X-Curve does not affect digital headroom, because it's not burned in the soundtrack.
The X-Curve does affect, though, the RMS output SPL from the speakers.
If we want to know the maximum RMS level per front channel at 1 KHz is 75 + 10 + 2.02 + 18.21 + 0.64 = 105.87 dBC.

Last edited by Optimus_Fine; 06-20-2019 at 07:06 AM.
Optimus_Fine is offline  
post #548 of 585 Old 06-20-2019, 10:34 AM
AVS Forum Addicted Member
 
Roger Dressler's Avatar
 
Join Date: Jul 2000
Location: Oregon
Posts: 11,478
Mentioned: 91 Post(s)
Tagged: 0 Thread(s)
Quoted: 2948 Post(s)
Liked: 1694
Quote:
Originally Posted by Optimus_Fine View Post
In a large room cinema, is the frequency response arriving at the listening position supposed to follow the X-Curve or is the X-Curve a method to obtain a flat frequency response in such environments?
Arriving at reference location, 2/3 back in center.

Quote:
If the former is correct, wouldn't the pink noise have a slightly higher level in cinema rooms corrected with the small X-Curve?
Not if it's adjusted for 85 in each case.

Quote:
And if I was able to record a wide band pink noise equalized like the X-Curve and play it in a small room, would that be an incorrect calibration method?
Yes.

Quote:
To record a THX compliant narrow band pink noise, do I filter with a 4th order high pass at 500 Hz and a 4th order low pass at 2000 Hz?
Yes.

Quote:
Are soundtracks with Dialnorm -27 supposed to be played at Reference or left attenuated -4dB by the decoder?
At any level you prefer, as you own the volume control. If you want "ref level" then yes, the dialnorm gain reduction needs to be cancelled.

Deadwood II Theater (Previous Deadwood Theater HTOM)
Anthem AVM 60 7.4.4; Classé SSP-800 PLIIx 7.4; MiniDSP OpenDRC-AN
Oppo UDP-203; Oppo BDP-93; Win7 media PC w/Roon+Kodi; Roku Ultra; DirecTV Genie
Adam Audio S3V/S3H LCR, KEF Ci200QS 4 srrnd, Tannoy Di6 DC 4 hts, Hsu ULS-15 4 subs
JVC RS520; Stewart Cima Neve screen 125" diag 2.35:1, MLP at 115"
Roger Dressler is offline  
post #549 of 585 Old 06-20-2019, 12:44 PM
Senior Member
 
Join Date: Jan 2015
Posts: 264
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 178 Post(s)
Liked: 34
Quote:
Originally Posted by Roger Dressler View Post
Arriving at reference location, 2/3 back in center.
Uhm... Yes, of that I'm aware of, but what is the outcome with the X-Curve?
A flat frequency response?
Or a frequency response with a spectral balance exactly like the X-Curve?
Quote:
Originally Posted by Roger Dressler View Post
Not if it's adjusted for 85 in each case.
Sorry, I should have asked, when calibrating to 85 dBC two rooms, one with the X-Curve and the other without, wouldn't the one without the X-Curve have a broader spectrum balance, thus less effective reading with C-weighting, leading to a higher gain and, ultimately, a slightly higher SPL in the midband?

Thanks.
Optimus_Fine is offline  
post #550 of 585 Old 06-20-2019, 02:17 PM
Advanced Member
 
Tomas2's Avatar
 
Join Date: Jan 2017
Location: New Orleans
Posts: 740
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 459 Post(s)
Liked: 716
Quote:
Originally Posted by Optimus_Fine View Post
...Are soundtracks with Dialnorm -27 supposed to be played at Reference or left attenuated -4dB by the decoder?
The dialnorm encoder setting (when the productions long term weighted average dialogue level is properly measured, and corresponding DN metadata is properly set) is used to normalize average dialogue to -31 dB below full scale zero.

If the production environment i.e. is calibrated (-20 dBFS = 85 dBC) he/she can still hit 105 dBSPL peaks on a single surround channel @ 0 dBFS excursion. On the other hand per your hypothetical, when the end-users decoder applies -4 dB to all channels (including the LFE) each surround channel will only reproduce 101 dBSPL peaks.

The long term average dialogue is now very precisely measured / metered:

LKFS (Loudness K-weighted, relative to Full Scale)

SAMSUNG QLED | ROTEL | MOREL | M&K | HAFLER | TECHNICS SP-25

Last edited by Tomas2; 06-27-2019 at 04:35 PM.
Tomas2 is offline  
post #551 of 585 Old 06-20-2019, 10:25 PM
AVS Forum Addicted Member
 
Roger Dressler's Avatar
 
Join Date: Jul 2000
Location: Oregon
Posts: 11,478
Mentioned: 91 Post(s)
Tagged: 0 Thread(s)
Quoted: 2948 Post(s)
Liked: 1694
Quote:
Originally Posted by Optimus_Fine View Post
Uhm... Yes, of that I'm aware of, but what is the outcome with the X-Curve?
A flat frequency response? Or a frequency response with a spectral balance exactly like the X-Curve?
The target is a response that fits inside the roughly +/- 3 dB window around the X-curve, with the least EQ. The goal is not the X-curve +/- 0.10 dB.

Quote:
Sorry, I should have asked, when calibrating to 85 dBC two rooms, one with the X-Curve and the other without, wouldn't the one without the X-Curve have a broader spectrum balance, thus less effective reading with C-weighting, leading to a higher gain and, ultimately, a slightly higher SPL in the midband?
The difference is less than 1 dB. But more importantly, what room would be calibrated flat with wideband pink at 85 dB?

Deadwood II Theater (Previous Deadwood Theater HTOM)
Anthem AVM 60 7.4.4; Classé SSP-800 PLIIx 7.4; MiniDSP OpenDRC-AN
Oppo UDP-203; Oppo BDP-93; Win7 media PC w/Roon+Kodi; Roku Ultra; DirecTV Genie
Adam Audio S3V/S3H LCR, KEF Ci200QS 4 srrnd, Tannoy Di6 DC 4 hts, Hsu ULS-15 4 subs
JVC RS520; Stewart Cima Neve screen 125" diag 2.35:1, MLP at 115"
Roger Dressler is offline  
post #552 of 585 Old 06-21-2019, 07:49 AM
Member
 
Join Date: Feb 2015
Posts: 91
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 50 Post(s)
Liked: 1
Roger, thi&#115; i&#115; intere&#115;ting, "when the end-u&#115;er&#115; decoder applie&#115; -4 dB to all channel&#115; (including the LFE) each &#115;urround channel will only reproduce 101 dBF&#83; peak&#115;."

Can you confirm. I&#115; it becau&#115;e of thi&#115; I need to increa&#115;e the volume
by +4 dB to achieve the &#115;ame level the one which do not have a -27 dBF&#83; applied?

Roger, by reading your po&#115;t ghe picture i&#115; th&#115;t you &#115;ugge&#115;t it &#115;hould be calibrated 85 dB, like THX i&#115; in equalizing, dubbing and cinema&#115; are. But &#115;till you a&#115;k in what room 85 dB!?
OBJECT is offline  
post #553 of 585 Old 06-21-2019, 07:42 PM
AVS Forum Addicted Member
 
Roger Dressler's Avatar
 
Join Date: Jul 2000
Location: Oregon
Posts: 11,478
Mentioned: 91 Post(s)
Tagged: 0 Thread(s)
Quoted: 2948 Post(s)
Liked: 1694
Quote:
Originally Posted by OBJECT View Post
Roger, thi&#115; i&#115; intere&#115;ting, "when the end-u&#115;er&#115; decoder applie&#115; -4 dB to all channel&#115; (including the LFE) each &#115;urround channel will only reproduce 101 dBF&#83; peak&#115;."

Can you confirm. I&#115; it becau&#115;e of thi&#115; I need to increa&#115;e the volume
by +4 dB to achieve the &#115;ame level the one which do not have a -27 dBF&#83; applied?

Roger, by reading your po&#115;t ghe picture i&#115; th&#115;t you &#115;ugge&#115;t it &#115;hould be calibrated 85 dB, like THX i&#115; in equalizing, dubbing and cinema&#115; are. But &#115;till you a&#115;k in what room 85 dB!?
Nanoo nanoo.

Quote:
Can you confirm. Is it because of this I need to increase the volume by +4 dB to achieve the same level the one which do not have a -27 dBFS applied?
Yes.

Quote:
But still you ask in what room 85 dB!?
I am suggesting wideband pink is not a recommended way to calibrate levels in any playback environment other than cinemas, and IMHO even that's open to debate. It's more accurate and consistent to use bandlimited pink noise, regardless if it's THX or Dolby flavor.

Deadwood II Theater (Previous Deadwood Theater HTOM)
Anthem AVM 60 7.4.4; Classé SSP-800 PLIIx 7.4; MiniDSP OpenDRC-AN
Oppo UDP-203; Oppo BDP-93; Win7 media PC w/Roon+Kodi; Roku Ultra; DirecTV Genie
Adam Audio S3V/S3H LCR, KEF Ci200QS 4 srrnd, Tannoy Di6 DC 4 hts, Hsu ULS-15 4 subs
JVC RS520; Stewart Cima Neve screen 125" diag 2.35:1, MLP at 115"
Roger Dressler is offline  
post #554 of 585 Old 06-22-2019, 12:59 AM
Senior Member
 
awediophile's Avatar
 
Join Date: Oct 2013
Posts: 409
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 295 Post(s)
Liked: 150
Quote:
Originally Posted by Roger Dressler View Post
The target is a response that fits inside the roughly +/- 3 dB window around the X-curve, with the least EQ. The goal is not the X-curve +/- 0.10 dB.
I haven't heard this before. Is this spelled out somewhere in the standard? I ask because knowing what I know now, this is precisely what *I* would recommend as a best practice. That is, assuming they are required to adhere to the standard and given currently available tools and technology. I might make an exception for the high frequencies, which could probably do well with more boost to get them up to higher than the X-curve target. Though obviously some systems have HF output limitations, which take priority.
awediophile is offline  
post #555 of 585 Old 06-22-2019, 01:21 AM
AVS Forum Addicted Member
 
Roger Dressler's Avatar
 
Join Date: Jul 2000
Location: Oregon
Posts: 11,478
Mentioned: 91 Post(s)
Tagged: 0 Thread(s)
Quoted: 2948 Post(s)
Liked: 1694
Quote:
Originally Posted by awediophile View Post
I haven't heard this before. Is this spelled out somewhere in the standard?
The standard in question is from 2017, SMPTE RP 2096-1, Cinema Sound System Baseline Setup and Calibration. It includes phrases such as:
In this recommended practice, electroacoustic response is specified as being within a calibration target ‘area’
rather than matching a target curve or line.

...the electroacoustic response of the screen channels between 50 Hz and 2 kHz should be essentially flat within the target area using as little equalization as possible...


But there is more discussion including how not to force EQ'ing into the 2 kHz knee.

Quote:
I ask because knowing what I know now, this is precisely what *I* would recommend as a best practice. That is, assuming they are required to adhere to the standard and given currently available tools and technology. I might make an exception for the high frequencies, which could probably do well with more boost to get them up to higher than the X-curve target. Though obviously some systems have HF output limitations, which take priority.
A key goal of the new document was to bring the latest practices for acoustic measurement and EQ to cinema technicians.
awediophile likes this.

Deadwood II Theater (Previous Deadwood Theater HTOM)
Anthem AVM 60 7.4.4; Classé SSP-800 PLIIx 7.4; MiniDSP OpenDRC-AN
Oppo UDP-203; Oppo BDP-93; Win7 media PC w/Roon+Kodi; Roku Ultra; DirecTV Genie
Adam Audio S3V/S3H LCR, KEF Ci200QS 4 srrnd, Tannoy Di6 DC 4 hts, Hsu ULS-15 4 subs
JVC RS520; Stewart Cima Neve screen 125" diag 2.35:1, MLP at 115"
Roger Dressler is offline  
post #556 of 585 Old 06-28-2019, 03:20 AM
Senior Member
 
Join Date: Jan 2015
Posts: 264
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 178 Post(s)
Liked: 34
I was thinking, in place of pink noise, why not use a very fast swept sine wave, say with a 1 second cycle, bouncing from 22 Hz to 22 KHz, or some other narrower frequency band?
Optimus_Fine is offline  
post #557 of 585 Old 06-29-2019, 10:50 AM
AVS Forum Addicted Member
 
Roger Dressler's Avatar
 
Join Date: Jul 2000
Location: Oregon
Posts: 11,478
Mentioned: 91 Post(s)
Tagged: 0 Thread(s)
Quoted: 2948 Post(s)
Liked: 1694
Quote:
Originally Posted by Optimus_Fine View Post
I was thinking, in place of pink noise, why not use a very fast swept sine wave, say with a 1 second cycle, bouncing from 22 Hz to 22 KHz, or some other narrower frequency band?
This is one of the tools used: Smaart

If sine sweeps worked better, they would have used it. Which is not to say they do not work. Audyssey and ARC use that just fine.

Deadwood II Theater (Previous Deadwood Theater HTOM)
Anthem AVM 60 7.4.4; Classé SSP-800 PLIIx 7.4; MiniDSP OpenDRC-AN
Oppo UDP-203; Oppo BDP-93; Win7 media PC w/Roon+Kodi; Roku Ultra; DirecTV Genie
Adam Audio S3V/S3H LCR, KEF Ci200QS 4 srrnd, Tannoy Di6 DC 4 hts, Hsu ULS-15 4 subs
JVC RS520; Stewart Cima Neve screen 125" diag 2.35:1, MLP at 115"
Roger Dressler is offline  
post #558 of 585 Old 06-29-2019, 11:47 PM
Senior Member
 
awediophile's Avatar
 
Join Date: Oct 2013
Posts: 409
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 295 Post(s)
Liked: 150
Quote:
Originally Posted by Optimus_Fine View Post
I was thinking, in place of pink noise, why not use a very fast swept sine wave, say with a 1 second cycle, bouncing from 22 Hz to 22 KHz, or some other narrower frequency band?
Quote:
Originally Posted by Roger Dressler View Post
This is one of the tools used: Smaart

If sine sweeps worked better, they would have used it. Which is not to say they do not work. Audyssey and ARC use that just fine.
So technically there are different measurement types and test signals along with different methods of analyzing the resulting data.

Cinema calibration specifies use of RTA of pink noise, which usually involves splitting the recorded signal and passing it into filter banks with a set of bandpass filters with a particular shape and fixed-octaves bandwidth and centered at different "bin" frequencies . The power output of these filters is then averaged over a long time.

A more comprehensive method of measurement is to measure sine sweep signal to determine the impulse response (IR) for the source at the measurement location. Note: not all methods that use sine sweeps are measuring impulse. For example, some methods may measure average SPL of a stepped sine, which gives different information than either the RTA or IR.

Technically, the IR completely characterizes the pressure response (both spectral and temporal aspects) at the measurement location, *provided* that the response is linear. By linear, I mean no significant compression or distortion of the output. What this means is that IR data can be analyzed in a variety of ways to recover the same information that would result using other methods like pink noise RTA or stepped sine SPL measurements.

However in practice, what most people appear to do is convert the raw IR data to transfer function data, throw away the phase, and smooth it somehow. This result is often referred to as "frequency response", even though the method of analysis has a big impact on the result and how it should be interpreted. For REW and probably most other programs, this "frequency response" data cannot be interchanged with binned pink-noise RTA data.

FWIW, it seems many cinemas these days get calibrated using some version of "frequency response" above even though it's not even compatible with the standard. That's probably not what is intended though.

Last edited by awediophile; 06-29-2019 at 11:54 PM. Reason: minor clarification
awediophile is offline  
post #559 of 585 Old 06-30-2019, 12:02 AM
AVS Forum Addicted Member
 
Roger Dressler's Avatar
 
Join Date: Jul 2000
Location: Oregon
Posts: 11,478
Mentioned: 91 Post(s)
Tagged: 0 Thread(s)
Quoted: 2948 Post(s)
Liked: 1694
Quote:
Originally Posted by awediophile View Post
Cinema calibration specifies use of RTA of pink noise...
SMPTE RP 2096-1 specifies: "1. Switch the analyzer to the proper mode (multi-time window transfer function for screen (Center, Left, Right) and LFE channels; RTA for surround array(s))."

Deadwood II Theater (Previous Deadwood Theater HTOM)
Anthem AVM 60 7.4.4; Classé SSP-800 PLIIx 7.4; MiniDSP OpenDRC-AN
Oppo UDP-203; Oppo BDP-93; Win7 media PC w/Roon+Kodi; Roku Ultra; DirecTV Genie
Adam Audio S3V/S3H LCR, KEF Ci200QS 4 srrnd, Tannoy Di6 DC 4 hts, Hsu ULS-15 4 subs
JVC RS520; Stewart Cima Neve screen 125" diag 2.35:1, MLP at 115"
Roger Dressler is offline  
post #560 of 585 Old 07-04-2019, 03:37 AM
Senior Member
 
awediophile's Avatar
 
Join Date: Oct 2013
Posts: 409
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 295 Post(s)
Liked: 150
Quote:
Originally Posted by Roger Dressler View Post
SMPTE RP 2096-1 specifies: "1. Switch the analyzer to the proper mode (multi-time window transfer function for screen (Center, Left, Right) and LFE channels; RTA for surround array(s))."
Thanks for the correction. Too bad it looks like this publication is pay-walled. I'd like to see some detail on this "multi-time window transfer function" mode, if there's any more to be found in that document. (Hopefully it's not an under-documented feature on proprietary hardware.)

Here's the thing though. Such capability did not exist when the X-curve standard was established. SMPTE is now recommending *different* measurement and analysis methods than were established in the original standard, yet SMPTE aren't recommending any new target(s)?

Like I said above, if the methods change, usually the resulting curves change too. Putting aside whether the original X-curve target(s) were ideal (at least on average across cinemas) for the pink noise RTA method, there's no reason to assume these curves would be ideal for these new and different methods. Either the standards committee was unable to agree on a better alternative, or they assumed the differences in methods weren't important.

They may not be too important if "+/- 3 dB using minimal EQ" is followed as recommended. I honestly don't know because I haven't seen the data I need to see from cinema measurements to make a determination. The discrepancies between pink noise measurement vs. other common methods may be surprisingly large in big rooms with long distance.

Unfortunately, it seems many if not most cinemas are now "calibrated" using some kind of auto EQ system that may follow an X-curve in-name-only approach by performing its own measurement and analysis methods but optimizing filters to peg the resulting curve (whatever it is) to an X-curve target. Most such systems give results that neither sound good nor are consistent with the X-curve methods. But hey, a computer did it so it must be right! (sarcasm)
awediophile is offline  
post #561 of 585 Old 07-05-2019, 03:34 AM
AVS Forum Addicted Member
 
Roger Dressler's Avatar
 
Join Date: Jul 2000
Location: Oregon
Posts: 11,478
Mentioned: 91 Post(s)
Tagged: 0 Thread(s)
Quoted: 2948 Post(s)
Liked: 1694
Quote:
Originally Posted by awediophile View Post
Thanks for the correction. Too bad it looks like this publication is pay-walled. I'd like to see some detail on this "multi-time window transfer function" mode, if there's any more to be found in that document. (Hopefully it's not an under-documented feature on proprietary hardware.)
The hardware and method is not proprietary. Checked out the documentation for the systems used for these measurements:
• SMAART, Multi-Channel Sound System Measurement, Optimization and Control Software, Rational Acoustics
• SIM-3, Audio Analyzer System, Meyer Sound Laboratories, Inc
• AFMG Systune, Live Sound Measurements in Real Time! Software, Ahnert Feistel Media Group
• D2, Acoustical Measurement System, AcoustX

Quote:
Here's the thing though. Such capability did not exist when the X-curve standard was established. SMPTE is now recommending *different* measurement and analysis methods than were established in the original standard, yet SMPTE aren't recommending any new target(s)?

Like I said above, if the methods change, usually the resulting curves change too. Putting aside whether the original X-curve target(s) were ideal (at least on average across cinemas) for the pink noise RTA method, there's no reason to assume these curves would be ideal for these new and different methods. Either the standards committee was unable to agree on a better alternative, or they assumed the differences in methods weren't important.
SMPTE published this report in 2014: TC-25CSS B-Chain Frequency and Temporal Response Analysis of Theatres and Dubbing Stages, which is listed here. It says one can register for free to download it. It states:
Quote:
7.1.2 Measurement Platforms
The bench-testing subgroup ‘laboratory-tested’ modern acoustic analyzers and technologies in theatres of various sizes and seating configurations. The tests showed that different manufacturers’ systems yield essentially identical results when subjected to the same test conditions. This validated the hypothesis that the technology’s measurements are not dependent on a specific test-system design.
This suggests the measurement method would not affect the curve.

Deadwood II Theater (Previous Deadwood Theater HTOM)
Anthem AVM 60 7.4.4; Classé SSP-800 PLIIx 7.4; MiniDSP OpenDRC-AN
Oppo UDP-203; Oppo BDP-93; Win7 media PC w/Roon+Kodi; Roku Ultra; DirecTV Genie
Adam Audio S3V/S3H LCR, KEF Ci200QS 4 srrnd, Tannoy Di6 DC 4 hts, Hsu ULS-15 4 subs
JVC RS520; Stewart Cima Neve screen 125" diag 2.35:1, MLP at 115"
Roger Dressler is offline  
post #562 of 585 Old 07-06-2019, 01:52 AM
Senior Member
 
awediophile's Avatar
 
Join Date: Oct 2013
Posts: 409
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 295 Post(s)
Liked: 150
Quote:
Originally Posted by Roger Dressler View Post
The hardware and method is not proprietary. Checked out the documentation for the systems used for these measurements:
• SMAART, Multi-Channel Sound System Measurement, Optimization and Control Software, Rational Acoustics
• SIM-3, Audio Analyzer System, Meyer Sound Laboratories, Inc
• AFMG Systune, Live Sound Measurements in Real Time! Software, Ahnert Feistel Media Group
• D2, Acoustical Measurement System, AcoustX
These systems are proprietary in the sense that the source code is not available and their computations are not documented in enough detail to either: (1) understand what these programs are actually doing; or (2) reliably reproduce their output.

I found the manual for the first system on the list: SMAART. I want to make a few notes: First, the manual actually distinguishes between two different smoothing methods it offers.

The first is called "fractional octave (logarithmic) smoothing". The word "logarithmic" could be providing a clue as to what information is being smoothed, but they may simply be remarking on the fact that the resolution is constant when viewed on a *logarithmic* frequency scale, as is usually the case when looking at spectral data. They do not clarify this elsewhere in the manual, nor do they indicate what type of smoothing kernel is used for this.

The second is called "linear complex smoothing (LCS)", which is less ambiguous to me. This method is mathematically the same as "frequency dependent windowing (FDW)" except that the FDW window is the inverse Fourier Transform of the LCS smoothing kernel. Unfortunately, they don't specify which window or kernel is used for this operation either. (A good "educated guess" is Gaussian.)

My other note about SMAART is that it provides a feature called "multi-time-window" in the context of "transfer function measurement", which appears to be what SMPTE RP 2096-1 is referring to. This feature is described as follows:

Quote:
MTW stands for multi-time-window. This is the default FFT selection for transfer function measurements and for a large majority of system tuning applications, there may rarely be any real need to change it. Rather than taking a single FFT for each input signal (reference and measurement) at a single sample rate, MTW uses a series of sample rate decimations and varying FFT sizes to produce a measurement with different time and frequency resolutions in different frequency ranges. There are a several benefits associated with this approach.

One benefit of MTW is that it sidesteps some of the time vs. frequency resolution trade-offs inherent in FFT analysis. Having only about 840 frequency data points makes MTW measurements much easier to
read than a single-size FFT measure with comparable low-frequency resolution. Another is that the use of shorter time windows at higher frequencies makes the coherence function a much more useful tool
for detecting timing mismatches between the reference and measurement than any single-size FFT based measurement with comparable low-frequency resolution. At 48k sampling rate, MTW produces better than 1 Hz resolution at the lowest frequencies, compared to ~1.5 Hz for a 32K FFT, with higher computational efficiency, and with nearly 20 times fewer frequency data points than a 32K FFT, it is much less work for your graphics hardware to plot.
The software really shows its age here. Even a cheap laptop these days can crunch through large FFTs very quickly. This hasn't always been the case though.

As a side-effect of this method, there is a kind of FDW applied at the time of the measurement, except it's not necessarily smoothly varying. In fact, it's not exactly clear how the data from the FFT at each scale is combined. Another thing is that late arriving high frequency energy will be truncated by the measurement method, which may or not be important depending on what type of analysis one wishes to perform after the fact.

***

I'm not going to go through the trouble to dig into the other measurement systems listed above because I'm fairly certain that the situation with them is similar. How many users of these programs pay attention to such details anyway? I would also point out that it's pretty unlikely that anyone implementing a "multi time window" feature in their measurement software would do so in the same way as SMAART did. How would they know what to do? It's not documented. Hence, this data can't be reliably compared.

Quote:
Originally Posted by Roger Dressler View Post
SMPTE published this report in 2014: TC-25CSS B-Chain Frequency and Temporal Response Analysis of Theatres and Dubbing Stages, which is listed here. It says one can register for free to download it. It states:
[...]
This suggests the measurement method would not affect the curve.
I have that report and have read it practically cover to cover. It has a lot of interesting information, and also lacks a lot of critical information for me to answer questions I have about the behavior of cinemas vs. small rooms. Unfortunately, according to the report their raw data suffered from a high noise floor because of the type of signal used to measure the transfer function. This would make it hard to assess the contribution of late arriving energy.

That specific paragraph refers to their bench testing group. Is there a separate report for their work? Two critical questions I would ask are: (1) Which specific measurement systems and methods were actually tested? and (2) What exactly is meant by "essentially identical"? Does this assume a certain "margin of error" to be negligible? If so, what?

In my opinion, what their statement suggests is not correct. I do expect many different measurement methods to give results that appear similar, but often significant differences will arise at the broader scales, which are the aspect of response that are usually being optimized to the "target", whatever it is.

To give the example of my room. Even up at 8 kHz I see about 1 dB difference between RTA pink noise and 1/48th octave FDW (which is as close as I can get to whatever SMAART is doing). In terms of total impulse response energy, about 25% of it around 8 kHz is "late arriving", being outside the 1/48th octave window. This is despite the following: (a) I use horn speakers with ~90 x 25ish degree pattern at 8 kHz; (b) I sit relatively close compared to the room size (both of these contribute to higher direct-to-reflected sound ratio); (c) the room has a fair amount of fabric; and broadband absorption; and (d) the air itself absorbs sound fairly rapidly at that frequency (-0.5 dB-ish per meter, depending a lot on temperature and humidity).

From a theoretical standpoint, I expect cinemas will exhibit substantially larger differences than I observe in my "close to near-field" situation. Discrepancies could be 3-6 dB or more in the mid frequencies for cinemas. I don't know for sure without being able to see the right data. And to emphasize again, some of these discrepancies may be very sensitive to room acoustic conditions. I'm reluctant to generalize until I see the data.

Last edited by awediophile; 07-06-2019 at 01:58 AM. Reason: improve formatting
awediophile is offline  
post #563 of 585 Old 07-06-2019, 01:15 PM
AVS Forum Addicted Member
 
Roger Dressler's Avatar
 
Join Date: Jul 2000
Location: Oregon
Posts: 11,478
Mentioned: 91 Post(s)
Tagged: 0 Thread(s)
Quoted: 2948 Post(s)
Liked: 1694
Quote:
Originally Posted by awediophile View Post
That specific paragraph refers to their bench testing group. Is there a separate report for their work?
Yes indeed. It is only available to SMPTE members of 25CSS. It was not made public other than the excerpts and conclusions included in the released report.

Deadwood II Theater (Previous Deadwood Theater HTOM)
Anthem AVM 60 7.4.4; Classé SSP-800 PLIIx 7.4; MiniDSP OpenDRC-AN
Oppo UDP-203; Oppo BDP-93; Win7 media PC w/Roon+Kodi; Roku Ultra; DirecTV Genie
Adam Audio S3V/S3H LCR, KEF Ci200QS 4 srrnd, Tannoy Di6 DC 4 hts, Hsu ULS-15 4 subs
JVC RS520; Stewart Cima Neve screen 125" diag 2.35:1, MLP at 115"
Roger Dressler is offline  
post #564 of 585 Old 07-12-2019, 04:46 AM
Member
 
Join Date: Feb 2015
Posts: 91
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 50 Post(s)
Liked: 1
Great to be back home from Florida, Fort Lauderdale. I will always miss to come back. Went to see a few movies at Regal and AMC. Will write about the experience later on...

Awediophile and Roger, you have great text if it comes to that, thanx .
But there is a few things both of you did not took up when you speak about the SMPTE report of measurement with different equipment aka SMAART/R2D2/SIM3, -20/-18 dbfs, spl, 85 dBC slow, etc. I said about this earlier but nobody notice it...
It does not work the way you are pointing it out ex. by only speaking about a measuring device how good or bad it is. It is question about how you use it in what situation and why.
SMPTE is not suggesting how a dedicated acoustic treatment is done in a room vs. the loudspeakers in use. Neither is it talking about the goal of a dead room, half dead or how echoing.
To do for movies a dubbing stage, cinema or a blu-ray studio I would install a dedicated room acoustic treatment with half-dead goal with knowing the monitors behavior inside this acoustic goal and apply after all this the needed equalization with a SMAART etc. You can not achieve a proper x-curve within +-3dB without a proper acoustic treatment!

To screw up your head a bit I found a few full-range pink-noise files in net, Genelec, Dynaudio, Dolby and BlueSky have one for download... Interesting is that all of them have different level in them!
OBJECT is offline  
post #565 of 585 Old 07-12-2019, 02:40 PM
AVS Forum Addicted Member
 
Roger Dressler's Avatar
 
Join Date: Jul 2000
Location: Oregon
Posts: 11,478
Mentioned: 91 Post(s)
Tagged: 0 Thread(s)
Quoted: 2948 Post(s)
Liked: 1694
Quote:
Originally Posted by OBJECT View Post
SMPTE is not suggesting how a dedicated acoustic treatment is done in a room vs. the loudspeakers in use.
SMPTE is not a cinema design authority.

Quote:
Neither is it talking about the goal of a dead room, half dead or how echoing.
Well, ST 2096-1 does specify:
Quote:
7.8 Reverberation Decay Time

Knowledge of a room’s reverberation decay time can provide the basis for an explanation for certain sound
characteristics that cannot be fixed with equalization, such as upper-bass “boominess” or a lack of
intelligibility in the middle to upper frequencies. A typical 200 – 300 seat theater should have a mid-frequency
RT60 of ~0.5 to 0.6 seconds. It is recommended that the reverberation decay time be checked as part of:

 The first tuning of a newly constructed space if the reverberation decay time has not been verified as
part of the construction process; or

 If physical changes have been made to the space or its contents.

Refer to ISO standard 3382-2 Part 2 for methods and procedures to conduct a reverberation decay time
measurement.
Quote:
To screw up your head a bit I found a few full-range pink-noise files in net, Genelec, Dynaudio, Dolby and BlueSky have one for download... Interesting is that all of them have different level in them!
It is for that reason SMPTE defined a standard pink noise signal (ST 2095-1). It most closely resembles the Dolby noise (from certain hardware only), as that was the de facto standard for all these years.

Deadwood II Theater (Previous Deadwood Theater HTOM)
Anthem AVM 60 7.4.4; Classé SSP-800 PLIIx 7.4; MiniDSP OpenDRC-AN
Oppo UDP-203; Oppo BDP-93; Win7 media PC w/Roon+Kodi; Roku Ultra; DirecTV Genie
Adam Audio S3V/S3H LCR, KEF Ci200QS 4 srrnd, Tannoy Di6 DC 4 hts, Hsu ULS-15 4 subs
JVC RS520; Stewart Cima Neve screen 125" diag 2.35:1, MLP at 115"
Roger Dressler is offline  
post #566 of 585 Old 07-13-2019, 01:07 AM
Member
 
Join Date: Feb 2015
Posts: 91
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 50 Post(s)
Liked: 1
Thanx Roger.

Sorry, I actually meant HOW everything is done the way it should be done. You need a very good consultant who knows something about this things to correctly build up a dubbing stage, cinema or blu-ray studio with the correct goal in the END result. This type of information is not even available at Dolby or DTS and if they would some consultant do not understand what is written on them

There are only a few guys who can do it properly and the rest are just wanna be or cowboys. What I mean is that the market is a jungle out there that not even Dolby or DTS had time to check out how my experienced Regal and AMC is compared to what they actually could do to avoid this type of huge mistakes.
This is it what Brian McCarthy wanted to point out in the video his concerns about the huge flaw in the consultant service for this dubbing stage and cinema vs. the FFT freq. response curve goal in them which is a mess!
And on top of this the mixer apply wrong decisions in the sound track.

Because we do not have a proper pink-noise file...could you provide a link to correct one, please?

Last edited by OBJECT; 07-13-2019 at 01:26 AM.
OBJECT is offline  
post #567 of 585 Old 07-19-2019, 01:29 AM
Member
 
Join Date: Feb 2015
Posts: 91
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 50 Post(s)
Liked: 1
Have you test the latest Waterworld NEW blu-ray releases. Arrow release is having the Ulysses Cut (all 3 cuts) with 5.1 audio. The US disc is theatrical cut (also TV cut) with DTSX track. I did test and the DTSX 7.1 track is 8 dB louder than the Arrow release. The US print have the correct level on that track. The mix is also different on the US release. Picture quality in the Arrow release is completely different than in the US release.

Do you know in what house who have mix this two?
OBJECT is offline  
post #568 of 585 Old 07-19-2019, 07:40 AM
AVS Forum Addicted Member
 
Roger Dressler's Avatar
 
Join Date: Jul 2000
Location: Oregon
Posts: 11,478
Mentioned: 91 Post(s)
Tagged: 0 Thread(s)
Quoted: 2948 Post(s)
Liked: 1694
Quote:
Originally Posted by OBJECT View Post
Because we do not have a proper pink-noise file...could you provide a link to correct one, please?
I cannot share the SMPTE file. However, if you have a pink noise signal, such as from REW, the 1/3-octave RMS level should be -33.74 dB FS.

If you prefer a wideband measurement, the RMS Level from 22.4 Hz – 22.4 kHz should be -19 dB FS.

Deadwood II Theater (Previous Deadwood Theater HTOM)
Anthem AVM 60 7.4.4; Classé SSP-800 PLIIx 7.4; MiniDSP OpenDRC-AN
Oppo UDP-203; Oppo BDP-93; Win7 media PC w/Roon+Kodi; Roku Ultra; DirecTV Genie
Adam Audio S3V/S3H LCR, KEF Ci200QS 4 srrnd, Tannoy Di6 DC 4 hts, Hsu ULS-15 4 subs
JVC RS520; Stewart Cima Neve screen 125" diag 2.35:1, MLP at 115"
Roger Dressler is offline  
post #569 of 585 Old 07-20-2019, 01:35 AM
Member
 
Join Date: Feb 2015
Posts: 91
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 50 Post(s)
Liked: 1
OBJECT is offline  
post #570 of 585 Old 07-21-2019, 10:18 PM
AVS Forum Addicted Member
 
Roger Dressler's Avatar
 
Join Date: Jul 2000
Location: Oregon
Posts: 11,478
Mentioned: 91 Post(s)
Tagged: 0 Thread(s)
Quoted: 2948 Post(s)
Liked: 1694
Quote:
Originally Posted by OBJECT View Post
I just checked the Dub Stage noise and it's perfect.
wideband level -18.3 dBFS
22.4 Hz - 22,400 Hz BPF, -19 dBFS
What are you seeing?
JonasHansen likes this.

Deadwood II Theater (Previous Deadwood Theater HTOM)
Anthem AVM 60 7.4.4; Classé SSP-800 PLIIx 7.4; MiniDSP OpenDRC-AN
Oppo UDP-203; Oppo BDP-93; Win7 media PC w/Roon+Kodi; Roku Ultra; DirecTV Genie
Adam Audio S3V/S3H LCR, KEF Ci200QS 4 srrnd, Tannoy Di6 DC 4 hts, Hsu ULS-15 4 subs
JVC RS520; Stewart Cima Neve screen 125" diag 2.35:1, MLP at 115"
Roger Dressler is offline  
Sponsored Links
Advertisement
 
Reply AVS Forum® Podcasts

Tags
frontpage , Home Theater Geeks

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off