marcnjocelyn
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Information on audio files
Hello all,
Does anyone know where i could get some detailed information on audio files in general? Information that would answer questions like:
1. Does normalizing audio cause data loss?
2. What level should digital audio be recorded at for optimum quality?
3. If the audio track is too soft, is it better to increase the fader level, or normalize the tack?
Something that would answer those TYPES of questions...?
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ohhey
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RE: Information on audio files
July 15, 09 11:08 AM
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ORIGINAL: marcnjocelyn
Hello all,
Does anyone know where i could get some detailed information on audio files in general? Information that would answer questions like:
1. Does normalizing audio cause data loss?
2. What level should digital audio be recorded at for optimum quality?
3. If the audio track is too soft, is it better to increase the fader level, or normalize the tack?
Something that would answer those TYPES of questions...?
This is where you need to understand bit level. When recording at 16bit resolution an upward change in the level after the recording was made was bad. This is because most of the loudness values were used up on the loudest parts and the soft stuff was not very good quality. That didn't matter if you listened to it as is but if you boosted the low stuff you could hear how bad it was. Now days everyone should be recording at 24bit. The record level is no longer a big deal because 24bit has so many loudness values that even the soft stuff is very good quality and can be boosted after the recording is made. When recording at 16 bit there are only 65,536 possible levels with 24 bit there are 16,777,216 levels so the converters have lots left over to make even the softest stuff high quality. So make sure you record 24bit tracks and you won't have to worry about that stuff. Also if you do mastering where the level of your mix might need to go up after you export make sure all that is done in 24bit. Only bit reduce to 16bit as the very last step. And no, normalizing does't cause data "loss" it just might cause things to sound worse if it's a 16bit file.
post edited by ohhey - July 15, 09 11:12 AM
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bitflipper
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RE: Information on audio files
July 15, 09 11:43 AM
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I'd recommend "Digital Audio Explained for the Audio Engineer" by Nika Aldrich.
This is a well-written introduction to digital audio that you don't have to be a mathematician to understand. Though an introductory text, it doesn't skimp on the meaty details.
 All else is in doubt, so this is the truth I cling to. My Stuff
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marcnjocelyn
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RE: Information on audio files
July 15, 09 12:06 AM
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THank you gentleman. This leads to another question...
Should i be recording at 44.1 or higher?
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CJaysMusic
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RE: Information on audio files
July 15, 09 4:10 PM
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I record at 48khz and 24bit. and then export it to 44.1khz and 16bit when im done and want to burn to CD. At this time and age, you should be reocridng at 24bit.
Cj
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ohhey
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RE: Information on audio files
July 15, 09 4:20 PM
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ORIGINAL: marcnjocelyn
THank you gentleman. This leads to another question...
Should i be recording at 44.1 or higher?
If your target media is CD or MP3 I would stick to 44.1. If your sound card sounds better at the higher rates you might consider just getting a better sound card. Good modern gear sounds great at 44.1 / 24bit. If you are doing a DVD soundtrack you need to use 48K. By using the same sample rate as your target media you avoid resamples. In my experiance a resample always alters the sound and in some cases can throw off the groove (timing).
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Kalle Rantaaho
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RE: Information on audio files
July 15, 09 4:59 PM
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There's a ot of useful reading at tweakheadz.com
The guides are very well written and cover practically every aspect of pc recording and home studio activities.
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papa2004
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RE: Information on audio files
July 15, 09 6:49 PM
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If your target media is CD or MP3 I would stick to 44.1. If your sound card sounds better at the higher rates you might consider just getting a better sound card. Good modern gear sounds great at 44.1 / 24bit.
If you are doing a DVD soundtrack you need to use 48K.
By using the same sample rate as your target media you avoid resamples. In my experiance a resample always alters the sound and in some cases can throw off the groove (timing). Disregard everything in the above quote except the DVD soundtrack part. It's all ancient myth and "hogwash" with today's technology. (Sorry, Frank)...
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tweeksound
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RE: Information on audio files
July 17, 09 5:24 PM
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ORIGINAL: papa2004
If your target media is CD or MP3 I would stick to 44.1. If your sound card sounds better at the higher rates you might consider just getting a better sound card. Good modern gear sounds great at 44.1 / 24bit.
If you are doing a DVD soundtrack you need to use 48K.
By using the same sample rate as your target media you avoid resamples. In my experiance a resample always alters the sound and in some cases can throw off the groove (timing).
Disregard everything in the above quote except the DVD soundtrack part. It's all ancient myth and "hogwash" with today's technology. (Sorry, Frank)...
Could you possibly please expand on this new found information, or at least point me where you found it? I have done many tests with modern digital gear that suggests that recording at 48 for CD just to resample to 44.1 yeilds a less pristine recording than starting at 44.1 and staying there.
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tweeksound
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RE: Information on audio files
July 17, 09 5:36 PM
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1. Does normalizing audio cause data loss? Data loss, no. Fidelity loss, technically yes. Due to the logarithmic nature of amplitude, there must always be rounded numbers when changing the level of a recording. However the loss of normalizing up 6dB is the same as bringing the fader up 6dB as long as both the normalize process' resulting file and mix engine are of equal bit resolution (32FP or 64FP). There are some processors that will truncate the higher bit depth file after the process and that can be even more detrimental. 2. What level should digital audio be recorded at for optimum quality? There is evidence that suggests that most converters have an easier time converting audio that is about 10 - 20dB below full scale. And with 24 bit recording from most commonly the equivalent of 20 bit converters, there is no real gain in fidelity in reaching over at least -12dB. From what I've read I take it that there are few of us who actually have converters that produce 24 usable bits. 3. If the audio track is too soft, is it better to increase the fader level, or normalize the tack? Again, it's probably the same integrity wise. However, it's much quicker and easier to undo a fader move than to undo a process. And the fader move doesn't create an entirely new file.
post edited by tweeksound - July 17, 09 5:41 PM
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rstollen
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RE: Information on audio files
July 17, 09 7:44 PM
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ORIGINAL: papa2004
If your target media is CD or MP3 I would stick to 44.1. If your sound card sounds better at the higher rates you might consider just getting a better sound card. Good modern gear sounds great at 44.1 / 24bit.
If you are doing a DVD soundtrack you need to use 48K.
By using the same sample rate as your target media you avoid resamples. In my experiance a resample always alters the sound and in some cases can throw off the groove (timing).
Disregard everything in the above quote except the DVD soundtrack part. It's all ancient myth and "hogwash" with today's technology. (Sorry, Frank)...
OK Papa2004 - You can't just come in here and say Frank's post includes "ancient myth and "hogwash". You're going to need to elaborate on that.
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papa2004
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RE: Information on audio files
July 18, 09 7:41 AM
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ORIGINAL: tweeksound
Could you possibly please expand on this new found information, or at least point me where you found it? This is not "new found information". Tons of research studies and tests by serious (and I mean REALLY serious) engineers conducted over the past decade have clearly proven this. It's Saturday morning here & I don't have time to "point" you anywhere or to present a lecture on the subject. One could easily find plently of documentation and substantive data on the subject by doing an internet search. Basically, it's simple math and physics laws applied to audio wave properties. More samples per/second will yield a more accurate representation of the original input. ORIGINAL: tweeksound
I have done many tests with modern digital gear that suggests that recording at 48 for CD just to resample to 44.1 yeilds a less pristine recording than starting at 44.1 and staying there. "Less pristine..."? That "suggests" to me improper resampling methods/software, or inaccurate hardware (DAC's, amps, speakers, etc.,) or a combination of any of the above factors. ORIGINAL: rstollen
OK Papa2004 - You can't just come in here and say Frank's post includes "ancient myth and "hogwash". You're going to need to elaborate on that. See above replies. 
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CJaysMusic
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RE: Information on audio files
July 18, 09 7:46 AM
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You can't just come in here and say Frank's post includes "ancient myth and "hogwash". You're going to need to elaborate on that. He cant!!! He just did.. I agree with what Papa is saying, exspecially these below. Less pristine..."? That "suggests" to me improper resampling methods/software, or inaccurate hardware (DAC's, amps, speakers, etc.,) or a combination of any of the above factors. This is not "new found information". Tons of research studies and tests by serious (and I mean REALLY serious) engineers conducted over the past decade have clearly proven this
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Oaf_Topik
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RE: Information on audio files
July 18, 09 10:05 AM
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I'm not saying CJ and papa are wrong, but I've never been able to hear the difference (in tests by "serious engineers" with high end gear) The irony is, if you are lucky enough to sell songs and make a living, the delivery of your media will most likely be on low end MP3, and listened to on a pair of cheap ear buds by the majority of your audience.
post edited by Oaf_Topik - July 18, 09 10:10 AM
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