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Issues recording mics to 48khz but not 44.1khz - Help!

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Issues recording mics to 48khz but not 44.1khz - Help!

Postby JLH123 » Sun Apr 25, 2021 10:35 am

hi all, i am using AKG414 mics and a orion synergy core antelope interface, an Imac and Ableton. I have been recording for a year on 44khz without issue, i am recording something for visuals so i wanted to record in 48khz. I selected that in the interface, made sure that it was 48 in Ableton, but when i record every minute a so a noticable click comes into the recording, it sounds a bit like the noise that comes on when you first turn on phantom power but quieter. I really can't think waht else to do, i even changed the mac output speaker to 48khz, but they are not being used, as its thunderbolt wire from mac into interface and i am hearing it thourgh headphones from the interface.

I could just record in 44khz and then bounce it as 48khz after in ableton, esp if there are syncing issues?

I have checked all leads etc, so i dont think its that!
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Re: Issues recording mics to 48khz but not 44.1khz - Help!

Postby Hugh Robjohns » Sun Apr 25, 2021 1:07 pm

Regular clicks are often associated with devices not being correctly clocked.
So it sounds like something might not be getting the correct clock.

I'm not a mac user I'm afraid, so can't guide you through the mysteries of interface set up in the mac... but I'd go through everything carefully again -- the interface, the DAW, and anything else digital in your system, and make sure they are all being clocked sensibly!
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Re: Issues recording mics to 48khz but not 44.1khz - Help!

Postby JLH123 » Sun Apr 25, 2021 2:32 pm

someone told me it might be that my buffer size is 256, which has been fine for 44.1, but for 48, i should raise it to 512, as it needs more, perhaps thats a likely reason?
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Re: Issues recording mics to 48khz but not 44.1khz - Help!

Postby Sam Spoons » Sun Apr 25, 2021 3:00 pm

The difference between 44.1kHz and 48kHz is quite small so if it works reliably at 44.1 I'd be surprised if that was causing problems at 48 but it's easy to test, just reset the buffers and see if the clicks go away?
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Re: Issues recording mics to 48khz but not 44.1khz - Help!

Postby Wonks » Sun Apr 25, 2021 3:07 pm

A click every minute may be some other background task taking too long and not making the processor available when the audio engine needs it. A longer buffer setting will help but ideally you'd shut down the background app or stop it checking for updates or email or whatever it's doing on a timed basis whilst you're recording.
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Re: Issues recording mics to 48khz but not 44.1khz - Help!

Postby DanDan » Sun Apr 25, 2021 10:36 pm

Go into AudioMidi Setup, make sure everything it set to 48
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Re: Issues recording mics to 48khz but not 44.1khz - Help!

Postby merlyn » Mon Apr 26, 2021 4:53 pm

Wonks wrote:A click every minute may be some other background task taking too long and not making the processor available when the audio engine needs it. A longer buffer setting will help but ideally you'd shut down the background app or stop it checking for updates or email or whatever it's doing on a timed basis whilst you're recording.

If the problem was due to a background task then this would cause problems at 44.1k and 48k, no?
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Re: Issues recording mics to 48khz but not 44.1khz - Help!

Postby RichardT » Mon Apr 26, 2021 8:37 pm

Do you have GarageBand installed - if so see what happens there.

Clicks can result from overload of your CPU so that it fails to process the audio data in good time - raising the buffer size would fix this, as Sam has suggested.
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Re: Issues recording mics to 48khz but not 44.1khz - Help!

Postby Wonks » Tue Apr 27, 2021 9:08 am

merlyn wrote:
Wonks wrote:A click every minute may be some other background task taking too long and not making the processor available when the audio engine needs it. A longer buffer setting will help but ideally you'd shut down the background app or stop it checking for updates or email or whatever it's doing on a timed basis whilst you're recording.

If the problem was due to a background task then this would cause problems at 44.1k and 48k, no?

Sometimes these things are marginal. For the same buffer size, 48k is filling the buffer approx 8% faster than 44.1k. So a 256 byte 44.1k buffer is equivalent time-wise to a 235 byte 48k buffer.

If a time-triggered background process is hogging the system for just longer than the time it takes to fill the buffer at 48k, 5.33 milliseconds, but less than the time taken to fill it at 44.1k, 5.80 milliseconds, then you can get a glitch. Or the maybe processor just cant cope with all the tasks it’s running and processing the buffer in the time available.

I’ll grant you that it’s unlikely and is probably something else. But it is a possibility.

It’s something where increasing the buffer size will instantly cure the symptoms, whereas if it’s a software parameter that needs setting or a clocking issue, then it probably won’t.
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Re: Issues recording mics to 48khz but not 44.1khz - Help!

Postby JLH123 » Tue Apr 27, 2021 10:15 am

thanks for all your help everyone.
I don't think its a CPU issue, it never goes much above 5% as its new and i only use it for recording piano at moment. Ill try increasing buffer size next time. Recording seemed to work in 44.1, although there was one click in 30 minutes. Never happened when i recorded my album.

When i exported the project from Ableton in 48khz, the 11 minute track was exact same length? Should it of been different slightly?

When i put that on top of the visuals it wa still out of time. Visuals filmed on a iphone 12.

THe workaround I have found, is warping the final WAV of audio and changing the tempo from 120 to 119.85, so minimal you cant hear the change, but it matches the iphone filmed visuals.

so weird, any insight appreciated!
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Re: Issues recording mics to 48khz but not 44.1khz - Help!

Postby blinddrew » Tue Apr 27, 2021 10:30 am

There's a very good chance your phone is recording at 44.1 not 48. A lot of phones and cameras, including mid range SLRs don't record in 48.
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Re: Issues recording mics to 48khz but not 44.1khz - Help!

Postby Wonks » Tue Apr 27, 2021 10:44 am

Wonks wrote: For the same buffer size, 48k is filling the buffer approx 8% faster than 44.1k. So a 256 byte 44.1k buffer is equivalent time-wise to a 235 byte 48k buffer.

Sorry my explanation's wrong. Ignore the highlighted bit.
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Re: Issues recording mics to 48khz but not 44.1khz - Help!

Postby merlyn » Tue Apr 27, 2021 12:27 pm

JLH123 wrote:When i exported the project from Ableton in 48khz, the 11 minute track was exact same length? Should it of been different slightly?

No. Ableton has re-sampled the audio.

If it didn't re-sample and played back 44.1k at 48k, then yes, the audio would be shorter and higher in pitch. The samples would all be pushed slightly closer together.

If you imagine one second of digital audio at 44.1k there are 44100 samples. Now play that back at 48k and those 44100 samples don't span a whole second. The samples get closer together, it's shorter and the pitch goes up by about a semitone.

To avoid this software re-samples 44.1k to 48k. There are now 48000 samples in the hypothetical second meaning the length and pitch are preserved.
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Re: Issues recording mics to 48khz but not 44.1khz - Help!

Postby James Perrett » Tue Apr 27, 2021 3:12 pm

JLH123 wrote:When i put that on top of the visuals it wa still out of time. Visuals filmed on a iphone 12.

THe workaround I have found, is warping the final WAV of audio and changing the tempo from 120 to 119.85, so minimal you cant hear the change, but it matches the iphone filmed visuals.

so weird, any insight appreciated!

Digital audio clocks usually run at slightly different speeds in different devices so this is normal. One device might be running at 48.01kHz while another device might be running at 47.98kHz. If you want them to be in sync then you need to run some kind of synchronisation signal between them but this is impossible with most portable devices so adjusting the playback speed to match is usually the best way to do it.
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