Sample Rate Basics

[MaxGain]

(New user apologies in advance)
Live Lite 11.3.21

• Assume I have recorded a single track with the Ableton preference sample rate set to 44,100

• I trim the beginning/end of the track

• I add a return track for the the default reverb and delay plugins

• Finally, I create a 44,100 export

No other edits, clips, plugins.

If I now change the preference sample rate to 48,000, will the earlier sample rate impact any additional edits such that I should re-record the track?

[Tarekith]

Why are you wanting to change the sample rate to 48k at this point of the process?

[Calagan]

Hi

There's a real time sample rate conversion done by Live when you play audio files recorded in a different sample rate than the actual session (like, in your exemple, 44kHz files in a 48kHz session).

My experience is that it impacts a little CPU footprint and of course the real time audio quality is affected.
But it's truly minimal (as far as I can hear) and when you print/export the tracks, Live is doing quite a good job with its conversion. After years using Live, I don't care anymore about the quality of the conversion (when exporting) : it's truly transparent.
Especially if you play 44kHz audio files in a 48kHz session, I don't think you'll be able to hear any issue.

This is with WAV audio files.

Now, with plugins, it can sometimes (in very rare occasions) change the sound in a dramatic way.

Most of the time it will not change anything, you just may have a better sound with less aliasing (with some plugins : there will be no change with digital EQs for exemple). The difference between 44kHz and 48kHz is tiny, and it's usually an improvement, not the opposite. But even if it improves the sound, you will not notice much difference.

But sometimes you will have a noticeable different sound because of the way the plugin is coded : I experienced that with some very specific Diva presets (when a different sample rate is changing the filters sound and modulation, and It affects the pitch), with the Valhalla reverbs and with the Soundtoys' Crystallizer plugin, where changing the sample rate is actually modifying the pitch of the fx...
But again, usually (with say 99% of the plugins), a different sample rate has very minimal difference (it just sounds better with higher sample rate, especially non linear processing and synths).

So you should check if a different sample rate will not change the sound of some plugins, and you should be cautious with CPU footprint, but most of the time there's no issue at all in changing the sample rate of the project (especially when going with a higher one).

[MaxGain]

Thanks For the responses.

Let me rephrase my question because I think I'm missing some fundamental understanding about Ableton.

My interface is a Focusrite 8i6 192Hz/24 bit.

The interface does the AD conversion at the above rate and provides the input stream to Ableton.

If the sample rate set in the Ableton profile at the time of recording is set to 44,100, then that is how Ableton samples the input stream/track. If a higher sample rate for the track is desired, the track should be re-recorded at the higher rate.

Is this correct?

[Tarekith]

Correct, there's really no benefit to recording something at 44.1 if you ultimately want it to be 48k. You can't make up what you didn't record in the first place.

[MaxGain]

If I have experimented and recorded sessions at different sample rates, is there a way to go back and determine what sample rate was used for a given track? I can't seem to find this anywhere.

[Calagan]

It's not the sample rate of the track, it's the sample rate of the audio clips that makes sense (there's no such thing as the sample rate of a track, if by track you mean the differents tracks of the Live session)

You can check the sample rate of the clip in the little colored area that is displayed when in clip view
Exemple here (in green, it shows 44.1kHz and 24-bit) : https://www.ableton.com/en/manual/clip-view/

To switch from plugin view to clip view : shift+tab

[MaxGain]

Let me give you an example-
I have session (.als) recorded in January when the sample rate in the preferences was set at 44100. For that session, I had recorded, edited and rendered output at that rate and had not made any further changes.
The track was first recorded 1/5/2024 and the .als file shows a last modified date of 1/21/2024

Recently, I changed the preferences sample rate to 48000.
When I load that session, the rate that shows in the clip view reflects the current sample rate, not the one used earlier.

[Calagan]

Strange. You may have done something weird because it doesn’t work like that.
If you change the session’s sample rate again to 44khz, is the sr displayed in the clip changing again ? I guess it doesn’t.

I think you rendered to 48khz without noticing (even while running the session at 44).
I don’t see other explanation…

[MaxGain]

Understood, it does seem weird.
I just created a test session recording at 44. Then did a save-as, deleted the tracks and created another at 48. I then left the preferences at 48 and reloaded the 44 session and in the clip editor it displayed 44 as expected.
I then rendered it at 48 and the clip editor sample rate remained at 44.

Thanks for staying with me on this as it confirms that the original sample rate persists.

As to the other session, I can blame it on having a second scotch