Anyone have info about recording at 192khz

[waigy]

Hey man

Recently bought a motu traveler which seems like the business so far, though I'm having problems with clicks when recording 4 tracks simultaneously at 24/176.4 or 24/192khz.
I will eventually suss what is causing the clicks, but in the meantime I'm going to have to record at 24/88.2 or 24/96khz, as the unit works fine at these settings.
I would obviously like to use as high quality as I can since I have the capability to do it, (and maybe in about 5 years time we will be playing mp3's on our mobiles at 24/192 and laughing at 44.1).
I read somewhere that if I use 176.4 rather than 192, it will be better when mixing down to 44.1khz as it's exactly 4 times the final frequency ie: 44.1x4=176.4
Anyone have good info or a web link to a site with good info about the advantages of recording at 192khz and mixing down to 44.1 (technical info, dithering e.t.c.).

Cheers man

[130dB]

There was some fairly lenghty discussion about bit depth and sample rate waaaaay back in the past.

http://www.audioforums.com/forums/sh...ad.php?t=11160


This thread had some very good info about sample rate as well as bit depth, but unfortunately, a certain member has been deleted from the forum and so his posts are also gone, too. There is still some good info there, though.

http://www.audioforums.com/forums/showthread.php?t=7879

[af-dcwave]

NOthing like digging up some old threads there 130db.

I cannot imagine why you would be recording at anything above 44.1 if your final result is going to be CD or mp3.

[AndyH]

You might want to look at this current thread on the same topic.
http://www.audiomastersforum.org/amf...pic.php?t=5457

[130dB]

NOthing like digging up some old threads there 130db.

heh, It didn't seem like all that long ago until I saw the post dates when I was searching.
That really was a great thread. Its a shame that Ed's posts are missing.


After some experimenting, I went back to 24/44.1 for most all of my work.

[t14]

Timbre, this is the quality that gives any sound its unique character and is formed by the interaction of a fundamental frequency and a number of harmonics (additional frequencies). This is what makes a piano playing a 300Hz note/frequency sound different from a guitar playing the same note/frequency. Recording with a high sample rate allows the best reproduction of higher frequencies and their harmonics, e.g.. recording a 10kHz sound plus the six harmonics that make up the timbre of that sound would require a 60000Hz sample rate to faithfully reproduce that sound (each harmonic multiplies the fundamental frequency by a factor of the number of harmonics that make up that sound, so 10kHz X 6 harmonics is equal to 60kHz). Here we begin to see the important role that high sample rates play in the reproduction of sound through digital systems. A 44.1kHz sample rate will not be able to reproduce high frequency sounds while also capturing their harmonics, resulting in a flat, dead sound in the high end of the recording. A test one can do to illustrate this effect is to compare the sound of a recording made at 44.1kHz sample rate against that of a direct monitor of the sound through a mixer before it is processed by any AD converter. Invariably one will find that the analog source of the sound superior in tone to that of the 44.1kHz recording.

interesting link for further reading -- http://www.dspguide.com/ch22/2.htm

also Bill Gibson does a better job explaining harmonics in his books 'The Audio Pro Home Recording Course Vol. 2' chapter three.

Ultimately, any argument for higher or lower sample rates in digital recording has to be weighed against practical, logistic and in the end subjective factors. If recording at lower sample rate gives you the results you find pleasing and meets the requirements of your application than who's to say your wrong?

[af-dcwave]

...If recording at lower sample rate gives you the results you find pleasing and meets the requirements of your application than who's to say your wrong?

Exactly!
............................

[AndyH]

Quite aside from the fact that no human can be aware in any direct way that such high frequencies exist, they certainly are not part of anything one hears, there is no trace of those higher frequencies in the final 44.1kHz product. The final result is the same whether or not a higher sample rate was used when recording.

[robertruetz]

Hey man, the dogs can hear those frequencies... be kind to the dogs, man.

Le_Singe

[AndyH]

hound dogs too?

[t14]

Some good reads on timbre, harmonics and overtones.

http://en.wikipedia.org/wiki/Timbre

http://en.wikipedia.org/wiki/Harmonics

http://en.wikipedia.org/wiki/Overtones

[AndyH]

A little extra education never hurts but there was nothing in those entries to suggest that higher sample rates are important in the current context. Basically, the contention here is that any information, effect, what-have-you, that may be possible with higher sample rates are irrelevant if the end product is a lower sample rate. The potential improvement in anti-aliasing is the only possible exception I know about, and that is strictly to do with hardware quality, nothing to do with sound or hearing beyond the Nyquist limit. Whether or not higher sample rates buy anything for an end media that supports higher sample rates, such as DVD-A, is a different question, but the objective, logical answer there seems to be no, with some possible exceptions in very special cases.

[oldfriend]

Hello,

i agree with Andy here... aliasing, also called 'audio blurring' is the reason why higher samplerates are used in audio production... the final product is eventually down-sampled and dithered to 16bits @ 44.1Khz... so, if you are wondering if there is a difference in sound (perceived quality), if two mixes are made, one recorded and mixed at 44.1Khz and the other recorded and mixed at 192Khz and then subsequently both dithered and downsampled to 16bits 44.1Khz,?.. the answer is yes... and that's about the only reason there is,.. IMHO...

Best wishes and welcome to AF

[af-dcwave]

And since most stuff these days is being listend to on ipod as mp3s... you can just stop recording anything above 10k anyway lol So save disk space and just use 22khz and 24bit... lol ( I crack myself up sometimes) LMAO.....

[waigy]

Thanks again for the info so far.

After reading the Dan Lavry sampling theory pdf

http://www.lavryengineering.com/docu...ing_Theory.pdf

I had to go and lie down.
Maybe a bit more technical than I expected.
I understood the first and last paragraphs though.
Dan seems to be saying the same as a few of you guys, that it is pointless recording at higher than Dr. Nyquist suggested, and so I have payed a lot of money for a useless function(ie: the ability to sample at very high sample rates).
Am I right in saying that?

My original idea was to :
1. Record myself(acoustic guitar and voice) at the highest possible setting then,
2. Back up those wave files to dvd, then
3. Extrapolate or alias or antialias or Nyquistivate ar whatever it's called down to 16/44.1, then
4. Do my mixing, effects, mastering and cd burning e.t.c. using the 16/44.1 wave files.

I thought it might be a good idea to have the highest quality wave files available for the future when maybe everyone's hifi or mobile phone will be capable of playing 24/192 wave files(or mp9's as they will be known).

Another question is this :
If I record at 24/192 on my traveler then play that recording back using the traveler's outputs through an amplifier, am I hearing a truer representation of the sound of my guitar than doing the same at 24/44.1?
Or is what Dan Lavry is saying that, you get no improvement of sound at all above 44.1?
Dan also mentions using lots more cpu and hard drive resources at the higher sample rates, well I bought a 3ghz/1 gig ram laptop for that reason, so I don't have a problem using more resources or buying a faster/larger drive.

I have learned a lot so far from the info suggested here, but I haven't grasped it 100% so I apologise in advance if anyone is offended by this response.

Cheers again