44.1 ok for movie audio in DCP digital age?

matt_gh2

I'm working on producing a feature film. Most audio is recorded at 24/96, but a lot is being recorded at 44.1. I remember hearing that in terms of using on actual film, it needed to be 48. But given that I've heard most theatrical distribution is on Digital Cinema Package (DCP) these days, is it okay to have some of the audio recorded at 44.1?

TheNewDeal

You can shoot and edit anyway you like. But for final DCP delivery, most insist on 48k at 24 fps.

rrsduncan

It's not an insist, it's part of the DCI spec. The audio absolutely must be at 48k.

The spec does permit 96k as well but I've never made nor exhibited one that had this.

matt_gh2

@rrsduncan @TheNewDeal Thanks for info guys. We're just starting production so I'll make sure everything is recorded at 24/96 or 48K.

rrsduncan

DCP is my bread and butter so feel free to ask if you come across any problems. Hope it goes well

DrDave

There is absolutely no reason to record any audio at 44.1, since no one listens to CDs anymore. Record at 24/48, or 24/96 and if necessary use Weiss Saracon or the less pricey R8Brain to convert.

The reason for this is that you want the "good" sound to be the one you use for the main markets, and the "converted" sound to use for the small markets.

If you have CD spec in mind, like for a soundtrack, it then can be released on MP3 at 48, giving you a small but valuable edge in the online market which is the main market.

Fact is, 44.1 is a crap sample rate. 48 is better and closer to the optimal rate of ~60. 96 is farther away from 60.

You can argue from a mathematical point of view that 88.2 is a reasonable compromise, but most software and hardware is just not set up right for 88.2. Stick with 48.

matt_gh2

@DrDave Thanks for info. Didn't know that 48 is actually better than 96 - very interesting. I'm not committed to 44.1, it's just that for some unique scenes we have character's voices being heard over cell phones, and I just happened to play around with a voice recorder iphone app that gave us the sound we want, and that records in 44.1. I'm sure I can find another similar app with similar sound characteristics, that records in 48. Thanks.

DrDave

As a practical matter, you won't hear a difference between 48 and 96 :) I'm not saying it is better, it is just closer to a theoretical ideal. You might be able to process 96 in such a way that it is closer to 60, but your time would be better spent tasting beer.

majoraxis

Just a quick note regarding ~ 60k sample rate as the ideal sample rate. True if you are using an A/D converter that samples at 60k natively, but some A/D converters are actually sampling at 1-bit DSD sample rates then decimating (converting) to the target sample rate.

I have found on my Mytek 8x192 converter (which internally samples at DSD sample rates then decimates) for recording music, I like the sound of it at 96k over 88.2, 48, 44.1.

I also like the sound of DSP processing at higher sample rates, so even if 48k and 96k sounds very similar before processing, when doing EQing, compression and limiting etc, if giving the choice I prefer working with higher sample rate files.

Anyway, 48k over 44.1k for video work for sure... but if you have a 1-bit DSD based A/D converter, then give it a listen at 48k and 96k. That said, if you can't tell the difference, stick with 48k because doing a conversion to 48k from any other sample rate will typically not improve the sound quality and may degrade it (if ever so slight depending on the SRC (sample rate converter) you use).

DrDave

Mytek makes a great converter! However, exhaustive double blind tests by AES have shown that no one can tell the difference in sample rates. I'd like to believe it makes a difference.

tetakpatak

The best sampling rate of the WAV files for industrial conversion to DSD (so actually for the SACD) is 88.2 kHz

matt_gh2

Thanks all for your advice.

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