Converting 24bit 96k to 48k, how to????

[Jonathan Levin]

Hi everyone.

I'd like to take advantage of my SD 633 recorders' ability to record at 96k. I know the human ear can't reall tell the difference between 48 and 96, but it's there. In fact I think you can go up to 200 something range which I have know idea when and why you'd use that unless perhaps there are major sound affects, etc.

Anyway my editing program, FCP X apparently only likes 48k. Tests from others revealed audio drift if syncing to accompanying video.

So what is the best conversion method. Is it just a matter of opening it in something like Logic, then bounce new audio at 48k? Then Archive the 96k audio.

Thanks guys.

Jonathan

[Richard Crowley]

Let me see if I have this right.
You want to record in 96K.
You have not disclosed any compelling reason to record at 96K
You will need twice as much storage medium for equal clip length.
You will need to convert your 96K back to 48K for your NLE.
You have read reports of possible sync issues.

Sounds to me like considerable downside, with zero practical benefit.
Remind us again, WHY do you want to do this???

If it ain't "broke", don't attempt to "fix" it.

[Gary Nattrass]

Standards exist for reasons and to assist workflow, a 24 bit 48k recording will give you a frequency range or around 20-24khz plus a dynamic range of over 100db and that is ample enough for TV and Film.

As Richard says why re-invent the wheel when the one you have works already and you will hear no significant difference by the time it has gone through the editing process.

P.S the conversion may even introduce more problems and if you can hear above 16khz then you are lucky.

[Jonathan Levin]

Richard and Gary.

Thanks for your reply.

Let me try and explain my way out of this one:

1st, if I have this almost correct the human ear can hear between 200(????) and 20000khz. I've heard but can't recall if it is correct if you take 48000khz, divide that by 2 you get 24000khz, well beyond the range of human hearing. Am I close?

That being said, I totally understand that recording anything above that does not offer any benefit. However I come from a digital photography background and I have always shot the highest common denominator by taking advantage of RAW settings on my camera. This way I always have that master file to be able to offer any resolution of a shot I would ever need. Talk about storage craziness!

So that is why I was thinking 88khz, 96khz, or the unbelievable 192khz setting!!!! 192 is probably ridiculous.

After re-sizing original file to a working 48khz file, I would then just archive the original. At this point storage is not an issue I think even with three inputs going, which is probably all I'd need for most of what I do anyway. I'd have to test what a WAV Poly file weighs in at per minute. The sync issues would be a deal killer, but if properly converted, would this still be an issue?

I'd love to hear your thoughts.

Jonathan

[Jonathan Levin]

And one last point. If I were to record a a very long meeting or round table, I'd reconsider my settings, and go with 48khz. But for short VO or something where i record a few minutes to an hour of VO, dialog, interview, maybe 96khz.?????

JL

[Richard Crowley]

Even prime-time operations with practically unlimited budgets only use 96K for recording special sound-effects where they know they will be doing extensive post-production processing.

The ideal audio range has long been established as 20Hz to 20KHz. As you understand, the Nyquist–Shannon sampling theorem very roughly states that you can record up to 1/2 the sample-rate. So a sampling rate of 48KHz will theoretically record up to 24KHz. However, very very few mic preamps and almost NO microphones will pass anything above 20 KHz. And it is rather uncommon to find an adult in a modern industrialized part of the world who can still hear up to 20 KHz.

Recording at 88 or 96 or 192KHz sample rate is like using a 100 or 200 mega-pixel camera with cheap plastic lenses. Nothing prevents you from doing that, but there is no practical benefit, no matter how you might wish there were. It is roughly like having small children in the back seat asking "Are we there yet?" every 30 seconds. The sample rate is vastly over-specified for the signal of interest.

If you want to do something that will ACTUALLY improve what your audio track sounds like to people who view your videos, then get better microphones and hire people who know how to use them effectively.

All that said, I am rather surprised that FCP X can't handle other audio sample rates (as, for example Adobe Premiere has for at least a decade). But then Apple rather exited the professional market when they dramatically dumbed-down Final Cut and lost most of their professional user-base.

[Rick Reineke]

If 96K floats your boat Jonathon.. by all means.
Otherwise, I concur with Richard and Gary.

[Jonathan Levin]

Hi Richard.

After reading your post, there is no point for me to consider anything other than 48khz. Thanks for clearing that up.

Great analogy the 200 megpixel camera with plastic lenses. Point well taken. Also interesting to know that better audio capture equipment is the best way to get better audio, and 1) knowing how to use the stuff properly or 2) hire a sound guy.

Trust me on this, if it were not just a matter of a sit down interview and involved anything needing moving feet, a sound guy no matter what the budget. I understand! I can only do so much myself before something screws up. I know my limits. Hell I hired a teleprompter operator for a couple of jobs and they were a life saver. Never had a need for one until then.

FCP X can handle sample rates, but apparently if you just use a higher sample like 96khz in a timeline that is 48khz, the conversion is sometimes spotty and audio can lose sync with video.

And I finally get to disagree with! The idea that Apple exited the Pro App market is so 2011! While X has had it's share of growing pains, it is evolving into a really fresh and exciting way to edit. And quick. The comparison to IMovie and all those arguments is bullshit in my opinion. The idea is to get the job at hand done.

Hell FCP version 1 was no picnic either, but by the time they got to version 7, a great, albeit buggy, was there to use. The old version can't take advantage of multi-core 64bt processing, the new one can. And gone is all the menu bloat from the bad old days of analog/interlaced.

Didn't the guy who help develop FCP go over to Adobe to work on the still un-friendly to me Premier?

Go have lunch while rendering since you can't edit during? Those days are gone with X. Given time, X is going to be even more incredible, If Apple doesn't drop the ball. Again, early versions were really awful, but now at 10.2.1 years old, I am really happy to have made master files of all my old FCP 6-7 stuff and said good-bye to all that.

Jonathan

[Jonathan Levin]

Thanks Rick.

Already changed setting on the 633 back 48khz.

Such great advice here I can't believe it.

Jonathan

[Rob Neidig]

Jonathan,

I agree with the others that 96kHz is overkill for most video productions. With that said, no one has answered your original question.

If you have a 96kHz file, any number of audio editing programs can convert that easily to whatever other sample rate you want, including 48kHz for video editing. Sony's Sound Forge, Adobe Audition, even the free Audacity will do that easily.

Have fun!

Rob