QSC Underwater Symphony dcp

[Jon Dent]

Pretty sure Dolby was also involved with the 70mm 6 track magnetic format that established the 5.1 channel layout in the late 70's with Apocalypse Now.

[Tony Bandiera Jr]

Anybody else notice that weird popping/snapping sound when the big fish appears in the background near the end? It sounds like cycling or clipping artifacts from the bass ramp in the center and LFE channels. I'd almost like to use this since we have QSC amps across the board but those artifacts are bad. In the LFE those pops go up above 10KHz, which definitely ain't good.

Untitled.jpg

Anything above the crossover point in the LFE channel will not be seen by the amplifiers or speakers, so it won't hurt anything. The ticks will not be likely to stress or harm the HF drivers much, if at all, but would be audibly distracting.

Second, where did you get this sample from? I see "Realtek Speakers" mentioned, so if this came from your computer's soundcard derived from the YouTube clip, it means nothing. These artifacts could be from your computer, the audio codec used for the video, or Youtube's processing compression.

The ONLY valid sample would be a direct output from the server or cinema processor and run on a proper analyzer. If this did come from a server, playing back a proper DCP, more info on what analyzer was used would be helpful.

[Tony Bandiera Jr]

It's funny though Ioan Allen always spoke about how the Cinema business led the consumer business and that getting that Dolby name on the Marque was the best way to license the technology into consumer products. I imagine Dolby made far more money from licensing to the consumer market than they ever did selling cinema processors and NR units.

^^ This. I like how Sean did the tl;dr of my first post. (Side note, I had seen tl;dr on a lot of things and had to finally look it up. Kids these days and their Newspeak, lol.)

[Jon Dent]

Second, where did you get this sample from? I see "Realtek Speakers" mentioned, so if this came from your computer's soundcard derived from the YouTube clip, it means nothing. These artifacts could be from your computer, the audio codec used for the video, or Youtube's processing compression.

The ONLY valid sample would be a direct output from the server or cinema processor and run on a proper analyzer. If this did come from a server, playing back a proper DCP, more info on what analyzer was used would be helpful.

I downloaded the DCP from the link at the beginning of the thread and loaded the 7.1 .mxf audio file into Audacity. So my soundcard has nothing to do with it. Top waveform is the center channel, bottom is spectrum view of the LFE.

Here's the DCP loaded into Resolve. You can see the same pops there as well.
Untitled.jpg

[Tony Bandiera Jr]

Thanks for the reply Jon.

I do stand by my original comment however. This is not looking at the output from a server in the real world, so whether those pops are audibly present or not is not known by this test. You are looking at the raw data (a good thing) but without the LFE low pass crossover, so again those pops would not make it past the crossover in the sub channel.

Have you tried the DCP in your theatre yet? It would be interesting to know if the pops show up there. As I stated, they would not cause any damage to any of your drivers. If you wish to be safer still, run the test with your fader at 5.

This reminds me of the old Addams Family Rap trailer, where they actually clipped the optical track so severely all the bass hits came out of the subs as a loud "BLAT". You can even see the two SVA tracks clash on all the bass hits.

[Jon Dent]

I'm not sure there is any kind of lowpass in our LFE chain. AES digital runs from our server to a CP750, then to the amp, that's it. The 120Hz LFE lowpass is supposed to be baked into the audio if I remember correctly.

Besides, that popping is also *very* present in the center channel and easily audible. That's why I wonder where it came from because it sure does not sound natural or organic compared to the rest of the soundtrack.

Eh this is all academic anyway.

[Jim Cassedy]

Yes, Dolby revolutionized cinema sound, but lets not forget one of the first, and most important
developments in the history of "talking pictures": The invention of Western Electric Noseless Recording™
- - which got rid of that annoying nasal quality present in the dialogue on early optical tracks by using an
advanced system of electo-acoustical filtering to achieve a high level of auditory olfactory obfuscation
Noseless-2.jpg

- JC -

[Mitchell Dvoskin]

From the early 1930’s… 948F5F66-566B-4208-B4E5-AE69A492AB53.jpeg

[Marcel Birgelen]

Yes, Dolby revolutionized cinema sound, but lets not forget one of the first, and most important
developments in the history of "talking pictures": The invention of Western Electric Noseless Recording™
- - which got rid of that annoying nasal quality present in the dialogue on early optical tracks by using an
advanced system of electo-acoustical filtering to achieve a high level of auditory olfactory obfuscation
Noseless-2.jpg

- JC -

Great find, first I thought the I somehow got all mingled up in the S, but it really seems to read NOSELESS and not NOISELESS. Maybe it worked by having the actors snort so much cocaine, their noses literally fell off.

[Tony Bandiera Jr]

I'm not sure there is any kind of lowpass in our LFE chain. AES digital runs from our server to a CP750, then to the amp, that's it. The 120Hz LFE lowpass is supposed to be baked into the audio if I remember correctly.

Besides, that popping is also *very* present in the center channel and easily audible. That's why I wonder where it came from because it sure does not sound natural or organic compared to the rest of the soundtrack.

Eh this is all academic anyway.

I am pretty sure that the CP750 incorporates a low pass filter in the subs, otherwise any noise artifacts from any processing or A/D conversions would find its way to the sub amps and speakers. And I believe you are correct that it could be encoded that way, but Audacity showed a bandwidth up to 8k, so at least as far as the raw audio was encoded, it didn't look like it was LFE filtered.

It's not all academic really, it is a great point of discussion. If there is an encoding problem QSC should be told about it. It would kinda defeat the whole purpose of an audio demonstration to have flawed audio in it.

[Tony Bandiera Jr]

Great find, first I thought the I somehow got all mingled up in the S, but it really seems to read NOSELESS and not NOISELESS. Maybe it worked by having the actors snort so much cocaine, their noses literally fell off.

Or whoever authored those titles has indulged in some devils dandruff

Either that, or we have one of, if not the, earliest examples of "Easter Eggs" hidden in credits.

[Sean McKinnon]

^^ This. I like how Sean did the tl;dr of my first post. (Side note, I had seen tl;dr on a lot of things and had to finally look it up. Kids these days and their Newspeak, lol.)

Thanks Tony! I am really good at repeating others good opinions! (don't feel bad I too had to look up TLDR a while ago)