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Author Topic: bit rate  (Read 2767 times)

rhkrhk

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bit rate
« on: December 16, 2014, 04:33:36 pm »

I'm recording my vinyl using audacity, set at 24 bit, with a bit rate of 96K or 192K, into WAV or FLAC files at level 8 (best)

When imported into an MC playlist, the wav files are reported to have a bitrate of 9216, and the flac files between 4800-4900.

CDs, by comparison, range between 350 and 700 bitrate.

Is the definition of bit-rate different in Audacity and MC?  Why the large discrepancy?

Fundamental audiophile problem is that my digitized dixieland vinyl files attenuate the hi-hats and cymbals as compared to the LP.
I think the 192K settings resolve the problem, but the reported bitrates confuse me.

explanation??? thanks
rhk
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ferday

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Re: bit rate
« Reply #1 on: December 16, 2014, 08:27:50 pm »

bit-rate is defined as "bits of data per second"

FLAC is a compressed file (like a .zip file), usually around 30-50% is about right....so at 50% compression you'll have 50% lower bitrate.  when you play the file (i.e. decompress it) the actual bitrate becomes the original value.
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mwillems

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Re: bit rate
« Reply #2 on: December 16, 2014, 08:42:58 pm »

I'm recording my vinyl using audacity, set at 24 bit, with a bit rate of 96K or 192K, into WAV or FLAC files at level 8 (best)

When imported into an MC playlist, the wav files are reported to have a bitrate of 9216, and the flac files between 4800-4900.

CDs, by comparison, range between 350 and 700 bitrate.

Is the definition of bit-rate different in Audacity and MC?  Why the large discrepancy?

Fundamental audiophile problem is that my digitized dixieland vinyl files attenuate the hi-hats and cymbals as compared to the LP.
I think the 192K settings resolve the problem, but the reported bitrates confuse me.

explanation??? thanks
rhk

Audacity probably isn't reporting a bitrate of 96K or 192K, those are common sampling rates which are not the same.  Sampling rate (44.1KHz, 96KHz, 192Khz, etc.) should not be confused with bitdepth (16 bit or 24 bit), which should not be confused with bitrate (which varies widely depending on the filetype).

Bitrate (the last one) is only a measure of quality for lossy formats (like mp3s).  By contrast, a given recording will have the same audio content in any lossless format even though the bitrate will differ (as noted by ferday).

Bottom line, as long as you're converting the rips to WAV or FLAC, the bitrate isn't an indicator of quality.
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AndrewFG

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Re: bit rate
« Reply #3 on: December 16, 2014, 11:55:07 pm »

Audacity probably isn't reporting a bitrate of 96K or 192K, those are common sampling rates which are not the same.  Sampling rate (44.1KHz, 96KHz, 192Khz, etc.) should not be confused with bitdepth (16 bit or 24 bit), which should not be confused with bitrate (which varies widely depending on the filetype).

Bitrate (the last one) is only a measure of quality for lossy formats (like mp3s).  By contrast, a given recording will have the same audio content in any lossless format even though the bitrate will differ (as noted by ferday).

Bottom line, as long as you're converting the rips to WAV or FLAC, the bitrate isn't an indicator of quality.

In short, bit rate equals the size of the file in bits, divided by the track duration in seconds :)
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Vincent Kars

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Re: bit rate
« Reply #4 on: December 17, 2014, 04:13:29 am »

Fundamental audiophile problem is that my digitized dixieland vinyl files attenuate the hi-hats and cymbals as compared to the LP.
According to Shannon-Nyquist your sample rate should be the double of the highest frequency.

Vinyl can contain signals up to 25 kHz (but higher values are reported) so 44.1 kHz (Nyquist=22) is probably a bit at the low site.
hi-hats are known to produce a lot of signals > 20 kHz

 When doing the AD conversion any signal in excess of half the sample rate generates an error.
 The input should therefore be band limited.
 Low sample rates like 44.1 kHz forces you to use very steep filtering (brick wall). This might be audible

Your best bet is to analyze the frequency of the recording using a 96 or 192 sample rate and check if there is live above 20 kHz
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