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Sample rate and bit depth survey

Posted: Sun Jul 12, 2020 11:17 am
by Lunkhead
I'm curious what folks use for their sample rates and bit depths when recording? I use 48kHz and 24-bit.

In case anybody isn't familiar with the terms, sample rate is the frequency with which a digital sample is taken of an analog audio signal when digitizing audio. Sample rate if I understand correctly is related to what range of input audio frequencies can be captured. And bit depths is the number of bits (the smallest unit of information in digital systems) are used to store each sample. Bit depth if I understand correctly is related to the dynamic (quiet/loud) range that can be captured. CD quality is 44.1kHz and 16-bit.

Re: Sample rate and bit depth survey

Posted: Sun Jul 12, 2020 11:21 am
by ken
24/48

Though I just realize my last couple of tracks were at 96K. I didn't realize the settings on my new interface were off. Totally explains why my system was starting to strain.

Re: Sample rate and bit depth survey

Posted: Sun Jul 12, 2020 3:25 pm
by jast
24/44.1 for the last 10 years or so.

To explain the terms a bit more: sample rate determines up to which frequency you can capture sounds - and nothing else. The theoretical limit is half the sampling rate, but for technical reasons (to prevent aliasing) a low-pass filter needs to be applied internally, and filters basically don't deliver a "perfect" cut-off, so depending on how "accurate" the filter is, you lose a little or a lot more than the theoretical optimum. Modern analog-digital converters (ADCs) use a trick called oversampling where they internally capture the audio at a much higher sampling rate - and then apply a much rougher filter (that is easier to implement). In other words: today's ADCs can deliver fairly close to the theoretical optimum.

Sample rate of 48 kHz = you can capture up to roughly 24 kHz.
Sample rate of 44.1 kHz = you can capture up to roughly 22.05 kHz.

Humans can perceive sounds at up to 28 kHz under lab conditions but the ears get much less sensitive starting at ~15 kHz, so probably you're good with either sample rate. Higher sample rates don't have much of a practical purpose in real life, though some audiophiles will claim differently.

The bit depth is basically the number of amplitudes that can be encoded - for instance, 16 bits can encode 65536 different amplitudes. This matters mostly for audio at the low end of the volume scale. Most audio system use a linear encoding of amplitudes, meaning that the 16 bits are mathematically evenly spaced over the resulting amplitude. Since human perception of loudness is logarithmic, this means that at the low end, the resolution gets significantly worse. If you process a 16-bit audio file to reduce it by, say, 90 dB, and then scale it back up, you'll find that it will sound quite mangled. This is due to the missing resolution in amplitudes and it's called quantization noise. It can be masked to some extent using dithering.

Bit depth of 16 bit = ratio of (full-scale) signal to quantization noise is roughly 96 dB. If your signal is at RMS -80 dBFS, the SNR is at around 16 dB, etc.
Bit depth of 24 bit = SNR is roughly 144 dB. If your signal is at RMS -80 dBFS, the SNR is at around 64 dB.

A higher bit depth is particularly relevant if you process audio multiple times, and you're not using a floating-point engine (which many modern DAWs do, but possibly not all plugins) - the quantization noise can add up over multiple rounds of processing.

Re: Sample rate and bit depth survey

Posted: Sun Jul 12, 2020 9:44 pm
by fluffy
I also use 44.1/24. Recording at 48KHz means there'll be a higher chance of artifacting when downsampling to 44KHz for the actual encoding, and 24 bits is plenty of headroom for the recording/mastering process (and 16 bits is more than enough for the final output, most people can't even hear the difference past 12 bits for most music).

Re: Sample rate and bit depth survey

Posted: Mon Jul 13, 2020 8:53 pm
by ujnhunter
44.1/24 here even if I have gear that goes to some redonkulous 192kHz as both Jan and fluffy point out about the technical details and human hearing. Anything else to me is a waste of precious space for things I can't even hear. ::shrug::

Re: Sample rate and bit depth survey

Posted: Tue Jul 14, 2020 9:15 am
by irwin
48k/20-bit. Only reason was that years ago when I upgraded from ADAT-land to a DAW, I set it to what the ADATs spoke so I could transfer all my old projects into the computer, and I just never changed it. Perhaps it is time to revisit?

Мы нашли все таки где купить этот препарат без огромных затрат

Posted: Wed Oct 14, 2020 7:35 pm
by Heatherarita
Хорошие специалисты и прекрасный севрис в этой онко

Доктор рекомендовал аптеку с низкими ценами и качественными препаратами

Posted: Wed Oct 14, 2020 7:35 pm
by Heatherarita
Хорошие специалисты и прекрасный севрис в этой онко

Re: Sample rate and bit depth survey

Posted: Wed Oct 14, 2020 7:38 pm
by sleepysilverdoor
Russian pharma spam? Wow!

Re: Sample rate and bit depth survey

Posted: Wed Oct 14, 2020 7:51 pm
by jb
Baaaanned.

Re: Sample rate and bit depth survey

Posted: Thu Oct 15, 2020 5:43 am
by ujnhunter
Glad that Russian Bot reminded me to set my sample rate accordingly on my video camera before I started recording with the wrong sample rate this weekend! Phew!

Re: Sample rate and bit depth survey

Posted: Thu Oct 15, 2020 5:47 am
by jb
Weird thing is that bot registered prior to when I changed the signup form to require pronouns. Which was months ago.

Prior to that I just looked for a reasonable username and email, and “Heatherarita” and “heathertan@gmail” seemed human.

So, my bad I think, but weird that it waited so long to get around to posting it’s shit.

Re: Sample rate and bit depth survey

Posted: Thu Oct 15, 2020 7:48 am
by fluffy
Oh yeah stealth spam is a thing. It’s a pretty common tactic for getting around post limits on boards which use a time delay to determine membership validity.

The ongoing spam Cold War is really annoying. Especially considering that the one thing spambots are trying to do (boost page rank) hasn’t been relevant for well over a decade.