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Recording, Bit Depth & Sample Rates ???

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Recording, Bit Depth & Sample Rates ???

Postby pianoworldstage » Fri Jul 10, 2020 10:30 am

Hi

In regard to recording solo piano (CFX Concert Grand in to Garageband) what bit depth and sample rate would be best recommended?
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Re: Recording Audio ???

Postby blinddrew » Fri Jul 10, 2020 10:39 am

Bit depth: 24 bit. Loads of headroom, no need to keep an eye on levels whilst performing, set and forget.
Sample rate: I'll defer to wiser heads on this, but as i understand it, there are potential anti-aliasing benefits to recording at 48kHz as opposed to 44.
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Re: Recording Audio ???

Postby The Elf » Fri Jul 10, 2020 10:55 am

blinddrew wrote:Bit depth: 24 bit. Loads of headroom, no need to keep an eye on levels whilst performing, set and forget.
Sample rate: I'll defer to wiser heads on this, but as i understand it, there are potential anti-aliasing benefits to recording at 48kHz as opposed to 44.
I remain uncertain of the benefits of 48kHz if the end aim will be to end up converting to 44.1, since SRC will be required - which itself is not a perfect technology. Anyone have some info/guidance on this?
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Re: Recording, Bit Depth & Sample Rates ???

Postby Hugh Robjohns » Fri Jul 10, 2020 11:06 am

If you plan to release your music, I'd go for 44.1kHz for convenience... or 96k if you have sufficient storage space and processing power in your system to cope.

As for the alleged advantage of 48kHz... it's largely a myth!

48kHz is a required rate when working with video for historical reasons, and, being slightly higher than 44.1k it does afford slightly more bandwidth and thus a slightly reduced risk of aliasing artefacts... but the difference between 48k and 44.1k is pretty insignificant. If you're worried about aliasing then you need to use 96kHz, or find a better 44.1k converter!

Most hardware asynchronous SRCs (aSRC) are pretty good these days, but going analogue via A-D and D-A conversion can be better if you can afford the latency.

Software SRCs are much more variable and some of those built into some popular DAWs are still diabolically bad. The Infinity Wave website allows most software SRCs to be compared... and it's quite an eye-opener!

(Hint: I always use either Adobe Audition or iZotope RX6... and I would avoid Protools and never use SADiE!)
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Re: Recording, Bit Depth & Sample Rates ???

Postby The Elf » Fri Jul 10, 2020 11:19 am

Hugh Robjohns wrote:Software SRCs are much more variable and some of those built into some popular DAWs are still diabolically bad. The Infinity Wave website allows most software SRCs to be compared... and it's quite an eye-opener!
Errr... Very interesting. Wonder what it means!?

I didn't even understand the help text! :lol:
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Re: Recording, Bit Depth & Sample Rates ???

Postby Dan LB » Fri Jul 10, 2020 11:32 am

pianoworldstage wrote:Hi

In regard to recording solo piano (CFX Concert Grand in to Garageband) what bit depth and sample rate would be best recommended?

I think there might be a bit of confusion here....

Are you recording an actual acoustic piano with microphones?

Your previous posts lead me to believe you're using the Garritan CFX plugin
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Re: Recording, Bit Depth & Sample Rates ???

Postby Hugh Robjohns » Fri Jul 10, 2020 11:41 am

He is... but there are options for setting up Garageband...
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Re: Recording, Bit Depth & Sample Rates ???

Postby Hugh Robjohns » Fri Jul 10, 2020 11:58 am

The Elf wrote:Errr... Very interesting. Wonder what it means!?

If you compare the Sweep plots for the DAWs I mentioned it will become obvious.

Basically, imagine a sweep tone in a 96kHz system. It can range up to 48kHz. If that signal is sample-rate converted down to a 44.1k system, everything above 22.05kHz should be removed, and the resulting sweep plot should show a single clean line rising from left to right and then stopping.

If the SRC produces aliasing, you'll see an aliased image of the sweep coming back down, and possibly other aliases cris-crossing in the background. The brighter those lines, the worse the aliasing. Check out the SADiE 6 plot... :shocked:

The 1kHz tone plots are another way of showing the amount and level of those aliases and other spurious junk. The lower the level of the white 'grass', the better...

The Passband and Transition plots just show the shape and turnover frequency of the reconstruction filtering in 'overview' and 'closeup' views. An ideal filter response would be a flat line ending in a vertical 'brickwall' at 22.05kHz. In practice that's not possible, so the filtering will start at a lower frequency and round into a near-vertical dive.

The Phase response plot shows the amount of phase shift introduced by the filter. As most are 'linear phase' filters there is no phase shift and you get a flat line. But a few are 'minimum phase' and in those you will see the phase lag at high frequencies (eg. Ferocious Sampler-minimum phase plots).

Similarly, the Impulse response plots shows the, er, impulse response. With linear phase filters you will see pre- and post-ringing, and the main spike being delayed in time (to the middle of the time window). With minimum phase filters there is no pre-ring, but the post-ring is usually longer and the spike is earlier (to the let of the time window) because there is less filter latency. If the filter is more gentle, the ringing will be shorter, and steeper filters have more ringing.

Again, compare the Ferocious Sampler standard and steep plots, looking at the impulse and transition band plots.
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Re: Recording, Bit Depth & Sample Rates ???

Postby RichardT » Fri Jul 10, 2020 12:11 pm

pianoworldstage wrote:In regard to recording solo piano (CFX Concert Grand in to Garageband) what bit depth and sample rate would be best recommended?

I would check the sample rate of the product, which is probably 44.1kHz, and use either that or 96kHz at 24 or 32 bit.
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Re: Recording, Bit Depth & Sample Rates ???

Postby The Elf » Fri Jul 10, 2020 12:26 pm

Hugh Robjohns wrote:
The Elf wrote:Errr... Very interesting. Wonder what it means!?

If you compare the Sweep plots for the DAWs I mentioned it will become obvious.
Hopefully.

I'll take some time to examine the plots and let this all sink. in. I'm always open to being educated.

Thanks for taking the time to explain, Hugh. It's always very much appreciated. :clap: :thumbup:
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Re: Recording, Bit Depth & Sample Rates ???

Postby Hugh Robjohns » Fri Jul 10, 2020 12:35 pm

No problem. It's a fascinating site if you're a bit geeky... and a useful comparative resource if you're curious about the quality of software SRCs in the DAWs and audio editors you're using.

I stumbled across it found it when I was trying to track down some information after hearing noises that shouldn't have been present when SRC-ing material in SADiE 5. I was shocked to discover the built-in automatic SRC facility was so atrocious.... and the plots on that site for SADiE 6 came from me! It is no better... :cry:

Thankfully most DAWs are reasonable now, and many have improved a lot over the last few years, but some are still quite grim and a few remain disappointing -- PT being one! DP being another...

There's really no excuse for anything less than technical perfection these days, and many can now deliver exactly that. As I said earlier, I use RX or AA for any off-line SRC work I need to do.
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Re: Recording, Bit Depth & Sample Rates ???

Postby pianoworldstage » Sat Jul 11, 2020 12:53 pm

OP,

So there is NO bit depth and sample rate chosen when recording MIDI? but rather when exporting a MIDI project to audio is when a bit depth and sample rate is required?

Therefor if one chooses to export a MIDI project to 24 bit, thus rendering a 24 bit audio recording?

When then is the point when red book standard requires a 16-bit 44.1kHz for CD compatibility.
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Re: Recording, Bit Depth & Sample Rates ???

Postby desmond » Sat Jul 11, 2020 12:57 pm

pianoworldstage wrote:So there is NO bit depth and sample rate chosen when recording MIDI?

MIDI has absolutely nothing to do with audio at all. It's just instructions to various instruments to ask them to play notes.

pianoworldstage wrote:but rather when exporting the MIDI project to audio is when a bit depth and sample rate is required?

Yes, because now you are recording the *sound* the instruments make when they are asked to play notes, to an audio file.

pianoworldstage wrote:Therefor if one chooses to export a MIDI project to 24 bit, thus rendering a 24 bit audio recording?

Yes.

pianoworldstage wrote:When then is the point when red book standard requires a 16-bit 44.1kHz for CD compatibility.

Because it's generally better to work at a higher resolution, then reduce down to the required target format, as you get the best out of your target format - rather than working within your target format the whole time (this applies in many areas of production, including graphics, video, and so on.)
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Re: Recording, Bit Depth & Sample Rates ???

Postby pianoworldstage » Mon Jul 13, 2020 1:21 pm

It's been an education, thank you to everyone for your input.
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Re: Recording, Bit Depth & Sample Rates ???

Postby MOF » Mon Jul 13, 2020 2:01 pm

Apple are now asking for the highest bit and sample rate files: “Use High-Resolution Sources.
To take best advantage of our latest encoders, use only 24-bit sources and send us the highest-resolution master file possible, appropriate to the medium and the project. Don’t upsample files to a higher resolution than their original format. Upsampling won’t recover or add information to an audio file. Similarly, don’t “bit-pad” or recapture 16-bit files in 24-bit.
Provide High-Resolution Masters.
Some mastering engineers prefer to control the SRC process by sending already converted files, however we ask that you deliver the highest native sample rate available. As technology advances and bandwidth, storage, battery life, and processor power increase, keeping the highest-resolution masters available in our systems allows for full advantage of future improvements to your or your client’s music”.
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