HTF Blu-Ray Review: Iron Man Ultimate Two-Disc Edition (RECOMMENDED!) - Page 3

CraigF · 10-20-2008, 04:46 PM

I had a couple of sound issues here, minor in the scheme of the good audio quality, which makes them stand out more to me. A few people mentioned related things.

I'm running a PS3->Denon 3808. So the 3808 gets LPCM, it won't know about any audio compression flag on the BD, and 3808 "night mode" compression is permanently turned OFF anyway. Similarly, the "dialog enhancement" option in the PS3 is turned OFF, so should be no compression at that end via the BD's flag if all is working right.

First thing: I can see why they enabled that flag on the BD, because I found there were numerous places where the dialog was practically lost in the other sound, though it could have sometimes partly been Downey's clipped speaking manner too. Of course I could bump the center level, but just saying, I never had to do that before.

Second thing: the dynamic *range* (not the average scene level) didn't seem as large as it should have in some scenes. Also, as somebody already mentioned, the average level seemed lower than usual for a BD, but by no means the lowest I've seen. No problem with that, turn it up... (I do not use the 3808's amps, at LOUD my external amps are barely past idling, so that's not it.)

Since I didn't see this in a theater, I don't know how the BD compares, if this was the way the sound was designed. I am of course wondering if there's some sneaky compression thing happening, some flag or option I missed. I hate dynamic range compression. I really noticed/thought this with Batman Begins BD too (didn't see that in the theater either), but with no other BDs to date.

Chris Atkins · 10-20-2008, 05:42 PM

Craig, even with DRC off in the PS3 (I send LPCM from the PS3 so DRC isn't an issue on the receiver end), I still have to turn Iron Man up to -12 on my Onkyo 705. Usual listening range is -20 to -18 (rewatching the new Indiana Jones last night, I was between -26 and -20 depending on whether it was an action scene or a dialogue heavy scene).

CraigF · 10-20-2008, 06:28 PM

^ Did you notice the dynamic range seemed artificially limited at all? Like, did your natural sense of sound of "how things should be", assuming this film was reality, make it seem not quite right?

Here's what I'm beating around the bush about. It's not necessarily BD-related, but could be depending how it's recorded, I don't know nearly enough. I vaguely recall reading a lot some time ago about the limitations of most current AVRs' volume control chips. They have a limited dynamic range. Depending on what features you use, perhaps even "features" you have no control over, you may run into the limit of what these chips can handle. For instance, Audyssey I believe takes a toll. And I am wondering if a BD recorded at a "low" level, thus requiring you run at a higher volume level, causes the AVR to restrict the dynamic range to remain within the digital volume chip's capability.

Just a thought, I may be way out to lunch. The relatively pristine audio allows me to notice more details, and makes little things stand out more...

Edit: I thought I would add a simple example to (hopefully) clarify what I'm wondering about here.

Suppose your digital volume chip has a range from 0 to -80dB. Suppose the BD is recorded at such a level that you're listening at -10dB to get your usual volume level. Now suppose a 20dB explosion happens. That would require the volume chip to go to +10dB, which it can't do, so it would only go to 0dB thus making the explosion not seem as proportionately loud at only 10dB louder.

Second scenario: same hardware, except the BD is recorded louder and you're listening at -20dB for the same volume level. Now that 20dB explosion could go up to 0dB and you'd hear it's sonic impact more.

Note that this has nothing to do with your amplifiers and the actual sound level being produced. It has to do with the range of the volume chip in crunching the numbers in the data stream: when its "top number" is reached you just can't get any more volume = compression.

Chris Atkins · 10-20-2008, 09:11 PM

Craig, what you are saying is resonating with me. A lot of scenes in Iron Man, even with DRC turned off, seem to lack "punch" just when they should have lots of it (i.e. an explosion, collision between cars, etc.).

CraigF · 10-20-2008, 10:31 PM

^ Yes, it could manifest quite slightly, or a lot depending how you listen i.e. loudish for action movies (me!!), or more civilly... I mention it in this thread because this is one of the two action BDs I've really noticed it on so far, and this one does seem to be recorded at a lower average level, thus effectively consuming volume chip dB range. Or so my speculation goes...

It is somewhat relevant to this thread (I hope) beause the BD audio does not need to be recorded quite so low IMO, considering the movie's genre, many others are not. And the Denon 3808 is a mid-priced AVR probably no worse than the general public uses, and would use similar-generation/capability volume control chips with their apparently limited range...so the problem should manifest fairly generally.

Just to clarify, or explain too much...: Note that in that example above this is an imaginary digital volume chip. I'm sure they would all have more than an 80dB dynamic range these days. Also, the dynamic range of the volume chip (its "bit range") is not necessarily the same as the dB volume setting range you would see on your AVR display. But the chip does have a maximum "number" it can handle above which it chops. Some of the dynamic range is consumed by "accessory" electronic internal processing. The higher the number you run the preamplifier section at (what you see displayed), and thus the volume chip at, the less room you have left for peaks.

Paul D Snyder · 10-21-2008, 11:06 AM

I went out and bought a new Blu-Ray player just to watch this movie...(actually, I needed a new player as the old one wouldn't play it)...And it was well worth it!

Excellent movie both visually and sonically.

Paul



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