7.1 Audio Test BD-25 BluRay

[maxmercy]

Hey everyone,

I am going to make an audio test BD-5 (BluRay on DVD) in order to properly calibrate prior to doing scene captures in spec lab and to ensure headroom is abailable in worst case bass management scenarios.

I plan to include the following:

1. Tones for all channels at 0dBFS
2. Worst case scenario - all channels same signal at 0dBFS
3. Full bandwidth impulse track (click track) for all channels
4. Tonebursts for all channels

This disc will augment Soho54's Audio Test DVD available at AVS.

Unfortunately, I am limited to 640k Dolby Digital 5.1, as I cannot encode lossless, but it should be very useful for testing a system and esp room acoustics with the click track for audible echoes, and speaker limits with the tonebursts.

Any ideas for other additions to this disc?

JSS

[Infrasonic]

I must have this!

 

Yeah, my only request would be to have the tones in all the major HD codecs and PCM but I see that isn't an option right now. However, in a BD player when set to MPCM output one will get to test their system in PCM it's just that the original tones won't be actual lossless but it will help for those who use alternate settings for the various sound formats.

[maxmercy]

This will mainly be LF data, so the lossy AC-3 should be enough.

 

I can currently only generate sweeps down to 10Hz, but tones down to 1Hz. The impulse track is easy to do, and the tonebursts as well.

 

Everything will be encoded at -0.1dBFS. May get to burn an initial

Test disc tonight to see if it will encode w/o clipping.

 

I was thinking of doing mainly LFE tones 1-20Hz, and every 5-10Hz above.

 

How many worst case scenario tones do you guys want?

 

JSS

[maxmercy]

New development - I have found out how to do -0.1dB tonebursts down to 3Hz. So the toneburst values can be:

 

3Hz

5Hz

10Hz

12Hz

20Hz

25Hz

32Hz

40Hz

50Hz

63Hz

80Hz

100Hz

125Hz

160Hz

200Hz

250Hz

315Hz

400Hz

500Hz

630Hz

800Hz

1000Hz

1250Hz

1600Hz

2000Hz

2500Hz

3150Hz

4000Hz

5000Hz

6300Hz

8000Hz

10000Hz

12500Hz

16000Hz

20000Hz

 

If this is to be mainly a subwoofer disc, I can eliminate the higher freq tonebursts, but they could be helpful for determining the highest distortion-free volume level for any speaker, letting your ears be the judge....

 

JSS

[TimVG]

That would be a cool and very handy disk to own! Any chance it can be put up online when it's done?

[maxmercy]

The .iso file will be put up so that anyone can burn it to a single layer DVD. I think I will limit the scope of this disc to LFE and worst case scenario only, save for the impulse tracks for each channel. All data will be recorded at -0.1dBFS.

 

So far there will be Worst Case Scenario and LFE Tones, Tonebursts, Impulse, and a slow, descending sweep 250-10Hz to find rattles.

 

JSS

[Ricci]

I would just do the 1/3rd octave centers.

 

3, 4, 5, 6, 8 , 10, 12.5, 16, 20, 25, 31.5, 40, 50, 63, 80, 100, 125, 160, 200, etc...

 

 

I will pick up a disc just for this since I have been to lazy to put it together myself.

"2. Worst case scenario - all channels same signal at 0dBFS"

[maxmercy]

Are 3, 5, and 8Hz enough? I am having some issues encoding, first trial resulted in a new coaster....I think I know my error, though...

 

JSS

 

 

[lilmike]

Let me know if I can help at all.

[maxmercy]

Will do, plan to work on it some this weekend.

 

JSS

[FOH]

Wow, I really like this idea

 

Som time ago I was involved or initiated a thread @AVS with regard to finding a worse case scenario scene,... whereby gain stages could be set, speaker/sub systems tested etc, ie the most demanding scene known.

 

I examined several of my DVD/BD releases in a crude, spectrally weighted method of amperage drawn on a sub amp, at a given level. My methodology proved a bit too crude,..like non-starter crude, fun nonetheless.

 

I'm down for one.

[Sputter]

I use 'Bass,I love you' but i'd take one too.

[maxmercy]

While doing work for another project, I have discovered some things, and will be able to move on this project more. Will use lpcm for the audio at the fastest bitrate DVD will allow, and later make a BluRay disc with lpcm and HiDef audio and video DTS, Dolby and THX trailers.

 

JSS

[morca]

Just a new member here,but this is a great idea.

I,m gonna follow your topic

[maxmercy]

I will get to work on this more in early summer.  I'll update here as work progresses.

 

JSS

[maxmercy]

I have good news on this front.  I should be able to use linear PCM to make the tracks, and be 7.1, and still fit on a DVD-5 disc read as a BluRay!!!  Work will begin in earnest on this disc this summer.  I have one more glitch to overcome (menu for the disc), but it shouldn't be a big deal.

 

JSS

[deepthoughts]

Good plan.  Just a quick thought...  If you are going through all the effort, maybe also attempt to add a few tracks with different band-limited pink noise.  ie 40-80Hz, 30-80Hz, 20-80Hz, 16-80Hz, 10-80Hz, and then also 10-20Hz, 10-40Hz, and 20-40Hz at maximum unclipped level... say 6dB crest factor.  This would add lots of real-world, worst case examples as tools to see what your system can handle.

 

I haven't yet had time to really play with the new beta version of REW, but does the HDMI output capability make this redundant if you have that capability?  If the output of REW can be referenced to a digital 0dBFS I would think most all of this would be available.

[maxmercy]

Did not know about REW's new capabilities. But this disc could still be used to evaluate a signal chain including the player.

 

Does REW's signal generator support impulses?

 

JSS

[maxmercy]

OK folks,

 

I have been working on this disc again, and will make it a full 7.1 BluRay disc.

 

So far, I plan to include the following:

 

1. True Pink Noise tones that are 12.3dB Crest and RMS of -12.3dBFS and -23dBFS to be nearly identical to the tones referenced in the following (see below).

 

http://www.meyersound.com/pdf/cinema_technical_papers/cinema_calibration_tech_report.pdf

 

 

2. Tonebursts in each channel and all 7.1 channels for worst case scenario at different freqs without the devastating effect long-term sinewaves can have on equipment.

 

3. Impulse tracks for each channel (and all 7.1), both max positive amplitude impulse (Dirac delta) and max positive amplitude followed by max negative amplitude impulse.  These are good for flutter-echo evaluation. 

 

4. A few slow sweeps for each channel to track down rattles in your room.

 

5. I may do a pink noise 'walk-around', panning the pink noise to every speaker in succession to see how timbre-matched your system is.

 

 

Any more suggestions?

 

There will be some THX, Dolby and DTS Trailers as well. 

 

 

JSS

[Ricci]

I would like an absolute worst case LFE channel plus 5 or 7 redirected bass channels all just below clipping. Identical 30Hz centered signal on all channels that will coherently add with each other and LFE to produce the theoretical maximum worst case signal level. It should probably be a short duration that repeats every few seconds as it would be dangerous to equipment health.

 

I want this test as a means of setting gain structure and evaluating clipping of the SW electronics. I would probably not even have the speakers connected for this.

[maxmercy]

All tone bursts will include 'worst case scenarios', as well as the impulse track.

 

JSS

[FOH]

This is a wonderful idea, I've enjoyed most every "test" type disc I have. Also, I've always wanted some type of worst case scenario test material, or actual program material.  

 

Question;

 

"Tonebursts in each channel and all 7.1 channels for worst case scenario at different freqs"

 

At different freqs?

 

 

Thanks

[Infrasonic]

I want all these things.

[maxmercy]

I intend to have each tone burst and impulse track as one track that goes from channel to channel and then worst case.....

 

Pink noise level cal files will be for individual channels only, but I can also include a worst case...

 

JSS

[maxmercy]

More work done on this project.  So far planned, all encoded at 48kHz, 24bit, 7.1 LPCM

 

Pink Noise - Mainly used for LCRS and subwoofer integration timbre matching, SPL calibration, and one amp clipping test

 

-'Around the Horn' PN pan with both Full Band (1Hz-20kHZ) and Narrowband (250Hz-4kHZ) PN -20dBFS RMS for timbre matching

-Clipping Test - 7.1 simultaneous all channel Full Band PN -12.3dB RMS with 0dB Peak

-SPL Speaker Cal with -20dB RMS PN Narrowband (500Hz-2kHZ) for C-weighted SPL meter 

-SPL Subwoofer Cal with -20dB RMS PN Narrowband (20Hz-80Hz and 20Hz-120Hz) for C-weighted SPL meter

-Possible 'crossing routes' Around the Horn with Full Band and Narrowband PN; e.g. Back Left Surround panning to Front Right, etc. 

 

 

ToneBursts - Used for amplifier clipping tests as well as distortion tests, these will likely be the most useful tools on the disc

 

- Tonebursts at -0dBFS at the following freqs for each channel: 1.5, 3, 5, 8, 10, 12, 16, 20, 25, 32, 40, 50, 63, 80, 100, 125, 160, 200, 250, 315, 400, 500, 630, 800, 1000, 1250, 1600, 2000, 2500, 3150, 4000, 5000, 6300, 8000, 10000, 12500, 16000, 20000

- Subwoofer Worst Case Scenario Tonebursts with 0dBFS signal simultaneously in all channels with freqs as above, from 1.5-250Hz

 

 

Sweeps - Used to find rattles in rooms

 

- Linear and logarithmic sinewave sweeps for all channels, full band and narrowband, encoded at -10 or -20dBFS

- Worst Case Scenario Subwoofer sweep encoded at -10dBFS all channels simultaneously

 

 

Impulse Track - Used to assess flutter echo/room treatment

 

- Impulse track for each channel encoded at 0dBFS

 

 

Any other requests?

 

 

JSS