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Hello! I'm trying to figure out this record offset thing. I actually didn't know about it much until just recently!

I'm using a Focusrite Saffire Pro 40.

What I'm doing is this:

I mad a signal with the Tone Generator, and sent that from the track output out of Out 7. I'm using a TRS cable from Output 7 to Input 1 on my interface to the line in jack.

I record the results, and this is what I got (see attachment).

I'm not quite sure what is going on here... Top track is the Tone Generator, the second track is the recording offset with 0 samples, then the third track is the offset with what I measured. Here's the problem though, as you can see, the re-recorded Tone Generator doesn't quite match the original signal. There is some strange lead in on the re-recorded tracks, and they don't match similar to how Mark Huyskens' video looks. In his video, the tracks look like they copy over pretty much identical. In my example, the lead in or start of the recording looks weird. Does anybody know why this would be or what any of this means?

EDIT: Furthermore, I also noticed that with Gregor's video, and Marcus', both of their interfaces place their audio earlier, whereas my interface places it later.

Attachments
Screen Shot 2022-09-04 at 8.28.45 PM.png

DAW's:
Studio One Professional 6.5.2
Pro Tools Studio 2023.12.1

Computer:
Mac Pro (Late 2013)
3 GHz 8-Core Intel Xeon E5
32 GB 1866 MHz DDR3
OWC Aura Pro X2 1 TB
AMD FirePro D300 2 GB
Mac OS 12.7.3 Monterey

Interface:
Audient EVO 16 w/ two Audient SP8's

Monitor:
LG 32' LCD connected via HDMI
Samsung 27" LCD connected via HDMI to Thunderbolt adapter
User avatar
by patrickviens on Sun Sep 04, 2022 9:36 pm
With that level of zooming, you get to see how the minimal effects the preamps gain and cable length/quality affect the original waveform. Looks like there is a loss of low end energy in track 3. But, if you can accurately spot your zero crossing point on the looped back return signal, the measure will be accurate enough.

I personally prefer to use Pipeline Mono to measure the offset :

Image

If you want to calibrate your send and return, scope is cool too :

Image

Windows 10 64-bit
IntelCore i7-4700MQ @2.40GHz, 16GB RAM, NVIDIA GeForce GT755M, MOTU Ultra-Lite MK3 Hybrid, IK Multimedia Axe I/O, Soundcraft Notepad 12FX Mixer/interface, MOTU Micro Lite Midi Interface, Studio One Professional 6.2.1
User avatar
by mikesupina on Sun Sep 04, 2022 10:17 pm
patrickviens wroteWith that level of zooming, you get to see how the minimal effects the preamps gain and cable length/quality affect the original waveform. Looks like there is a loss of low end energy in track 3. But, if you can accurately spot your zero crossing point on the looped back return signal, the measure will be accurate enough.

I personally prefer to use Pipeline Mono to measure the offset :

Image

If you want to calibrate your send and return, scope is cool too :

Image


Thank you for the reply! So, as far as track 2 and 3, those are actually the exact same; the only thing that changed was the record offset, and then I believe I clip gained the second one when trying to initially compare the original. But the thing that I don't understand is the stuff that's happening before the zero crossing point; it's doing a negative amplitude for a moment before going positive. I'm not sure why, and how to combat that.

DAW's:
Studio One Professional 6.5.2
Pro Tools Studio 2023.12.1

Computer:
Mac Pro (Late 2013)
3 GHz 8-Core Intel Xeon E5
32 GB 1866 MHz DDR3
OWC Aura Pro X2 1 TB
AMD FirePro D300 2 GB
Mac OS 12.7.3 Monterey

Interface:
Audient EVO 16 w/ two Audient SP8's

Monitor:
LG 32' LCD connected via HDMI
Samsung 27" LCD connected via HDMI to Thunderbolt adapter
User avatar
by mikesupina on Mon Sep 05, 2022 6:29 pm
patrickviens wroteWith that level of zooming, you get to see how the minimal effects the preamps gain and cable length/quality affect the original waveform. Looks like there is a loss of low end energy in track 3. But, if you can accurately spot your zero crossing point on the looped back return signal, the measure will be accurate enough.

I personally prefer to use Pipeline Mono to measure the offset :

Image

If you want to calibrate your send and return, scope is cool too :

Image


So, I believe I made an error, and did it correctly now. I measured the distance from Track 1 to the start of Track 2 (regardless of the stuff before on Track 2 before it starts to resemble Track 1), and I set the recording offset to that amount, and now, it would appear that the little bit of information before that was on track 2 doesn't appear anymore and they line up as they should! They don't completely phase cancel, but I assume that is to be expected since it's making a round trip from DA to AD via a TRS cable/preamp etc?

DAW's:
Studio One Professional 6.5.2
Pro Tools Studio 2023.12.1

Computer:
Mac Pro (Late 2013)
3 GHz 8-Core Intel Xeon E5
32 GB 1866 MHz DDR3
OWC Aura Pro X2 1 TB
AMD FirePro D300 2 GB
Mac OS 12.7.3 Monterey

Interface:
Audient EVO 16 w/ two Audient SP8's

Monitor:
LG 32' LCD connected via HDMI
Samsung 27" LCD connected via HDMI to Thunderbolt adapter
User avatar
by patrickviens on Tue Sep 06, 2022 9:17 pm
mikesupina wrote
patrickviens wrote They don't completely phase cancel, but I assume that is to be expected since it's making a round trip from DA to AD via a TRS cable/preamp etc?


Yes. Zooming at the sample level displays the inaudible mess existing at the extreme low levels. These bits are not relevant to measure the offset, neither, instead, you want to use the zero-crossing point that correlates to your test signal. If the components self-noise is visible, that is just too confusing. But snap to zero-crossing will snap just right.

See :

Image

Here below I have printed a sine wave a -12dbfs, I did not zoom so much (I don't care about the anomaly above), used snap to zero-crossing, split the region, and checked the event start & end difference in samples to set my record offset. 141 samples.

Image

But, usually, I just throw Pipeline in an empty song to measure the offset. Far simpler. The latency it reports can be ignored (50ms is rather 2,400 samples @48khz). Just check the sample offset reading. The result is the same. It is easier this way because the record offset is very much contextual and will always depend on many factors (will you want to to a loop back test every time you plug a device that introduce latency, or when you move a microphone?)

Image

Windows 10 64-bit
IntelCore i7-4700MQ @2.40GHz, 16GB RAM, NVIDIA GeForce GT755M, MOTU Ultra-Lite MK3 Hybrid, IK Multimedia Axe I/O, Soundcraft Notepad 12FX Mixer/interface, MOTU Micro Lite Midi Interface, Studio One Professional 6.2.1
User avatar
by mikesupina on Thu Nov 17, 2022 10:21 pm
patrickviens wroteWith that level of zooming, you get to see how the minimal effects the preamps gain and cable length/quality affect the original waveform. Looks like there is a loss of low end energy in track 3. But, if you can accurately spot your zero crossing point on the looped back return signal, the measure will be accurate enough.

I personally prefer to use Pipeline Mono to measure the offset :

Image

If you want to calibrate your send and return, scope is cool too :

Image


So, I didn't fully realize that pipeline made calculating this easier! How do you set it up? Should itbe a blank session? Do you put Pipeline on a mono track, set its output to an output on the interface, then set the input to any input, then hit the wrench icon? I was experimenting with it, and I see milliseconds on the right, and samples to the left of it. But when I hit the wrench icon, I see the blip of audio, but nothing happens. Am I missing something? I can drag the samples number until it says "0.0 ms"; is that how that works?

DAW's:
Studio One Professional 6.5.2
Pro Tools Studio 2023.12.1

Computer:
Mac Pro (Late 2013)
3 GHz 8-Core Intel Xeon E5
32 GB 1866 MHz DDR3
OWC Aura Pro X2 1 TB
AMD FirePro D300 2 GB
Mac OS 12.7.3 Monterey

Interface:
Audient EVO 16 w/ two Audient SP8's

Monitor:
LG 32' LCD connected via HDMI
Samsung 27" LCD connected via HDMI to Thunderbolt adapter
User avatar
by mikesupina on Thu Dec 01, 2022 6:05 pm
Bumping up :)

DAW's:
Studio One Professional 6.5.2
Pro Tools Studio 2023.12.1

Computer:
Mac Pro (Late 2013)
3 GHz 8-Core Intel Xeon E5
32 GB 1866 MHz DDR3
OWC Aura Pro X2 1 TB
AMD FirePro D300 2 GB
Mac OS 12.7.3 Monterey

Interface:
Audient EVO 16 w/ two Audient SP8's

Monitor:
LG 32' LCD connected via HDMI
Samsung 27" LCD connected via HDMI to Thunderbolt adapter

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