Topic: What RME gear gives correct delay compensation?

Hi,

I'm wondering if anyone has a formula, rule of thumb or a spread-sheet on which combinations of RME gear will give robust sample accurate delay compensation? I've found some very specific answers but it would be great to have the complete picture.

Two examples where this is useful:
1. You are recording overdubs with direct monitoring via TotalMix.
2. You are using parallell outboard compressor as hardware insert.

A few setup examples I'm wondering about (but it would be great to have a master sheet of all possible combinations):
1. Just a RME interface (UFX II for example) and nothing else.
2. Digiface USB -> ADI-2 FS
3. Madiface USB -> M-1610 Pro
4. Madiface Pro -> 12Mic
List goes on...

PS. Will MIDI on RME inferfaces be correctly delay compensated?

Re: What RME gear gives correct delay compensation?

Midi is always delay compensated and independent of the audio anyway. If everything works correct it gets a timestamp upon entering the system.
AFAIK only onboard converters are 100% correctly delay compensated by the driver, like when you use the UFX analogues.
With the madi and digiface converter latency is not compensated automaticely, since the driver can not know the latency. But this is not in the audible range but  in the few samples range.

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
Babyface pro fs, HDSP9652+ADI-8AE, HDSP9632

Re: What RME gear gives correct delay compensation?

Ok, I think I read somewhere that MADI was correctly delay compensated but it was difficult to understand completely and I'm not sure.

Wouldn't it be possible for the interface to know (for RME gear at least) what outboard converters has been connected and compensate automatically. For example, UFX II could teoretically know what latency M-1610 has and add that to latency compensation for that unit when it's been connected.

4 (edited by ramses 2022-05-23 15:11:29)

Re: What RME gear gives correct delay compensation?

At least some MADI devices support delay compensation, that e.g. all Octamic XTC (e.g. up to 8 chained after each other) will have the same latency so that you can connect two mics (for stereo) to two different XTCs and which will have the same time base.
Delay compensation is only possible for the RME devices following the old "8-port" scheme, see e.g. Octamic XTC manual for "delay compensation". But not newer devices with 12 ports like 12Mic. Then you need to connect 2 mics for stereo recordings best to the same preamp.

BTW, things like delay compensation were special extensions from RME for MADI when in the old days up to 8 XTCs have been connected to a MADI bus.
Nowadays a 12Mic has a higher port densities, so you connect only fewer number of devices, esp. at double speed.
And the converter latency additionally became a little smaller.
So that the latency in total through MADI is not so high anymore compared to 8x XTC in the old days.

BR Ramses
UFX+, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1650v4, Win10Pro21H2, Cub12Pro

Re: What RME gear gives correct delay compensation?

One driver can not compensate for 2 different latencies from different converters. The driver reports 1 value.
And it is good practice to connect 2 sources (Mics) that have a phase relation, to the same interface when recording. Except for this the exact number of samples a converter delays is not that critical.

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
Babyface pro fs, HDSP9652+ADI-8AE, HDSP9632

Re: What RME gear gives correct delay compensation?

Thank you very much!

So, for example, if I liked the M-1610 Pro and wanted to use it as my "interface" via a madiface USB, I would need to manually add delay compensation if I need that. A case where I might need sample accurate compensation is if I use outboards and want to mix it with the original audio. In that case, I believe transients benefit from sample accurate timing but I have not experimented with small errors like 3-4 samples.

Wouldn't it teoretically be possible for the interface to report the latency of the slowest connected converter and hold the internal converters/faster converters so that everything gets delivered at the same time to DAW? Then the drivers wouldn't need more then one latency value.

Re: What RME gear gives correct delay compensation?

hansrohdin wrote:

Thank you very much!

So, for example, if I liked the M-1610 Pro and wanted to use it as my "interface" via a madiface USB, I would need to manually add delay compensation if I need that. A case where I might need sample accurate compensation is if I use outboards and want to mix it with the original audio. In that case, I believe transients benefit from sample accurate timing but I have not experimented with small errors like 3-4 samples.

Wouldn't it teoretically be possible for the interface to report the latency of the slowest connected converter and hold the internal converters/faster converters so that everything gets delivered at the same time to DAW? Then the drivers wouldn't need more then one latency value.

It sounds easy enough but has not been implemented by any company.
I would say it is more about phase relation then timing with those short latencies. for example 4 samples dealy would flip the phase of a 10k sine wave.
This is only critical (and then very critical) if you mix the original signal with the external processed signal. Any offset will cause phasing issues. But even therefore is a trick if needed. You can send the audio through an AD[DA loop and through the Ext fx. Latency will then be identical.
This all sound way more important then it practically is. Unless you have very specific needs, which you don`t state, so we are in the dark here if it will be a practical issue or a non issue.
Also all I state is in regard to converter latency, when connected straight to for example a UFX. I have no clue about serial madi latency (or madi at all).

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
Babyface pro fs, HDSP9652+ADI-8AE, HDSP9632

Re: What RME gear gives correct delay compensation?

Thank you very much for sharing your knowledge!

vinark wrote:

Midi is always delay compensated and independent of the audio anyway. If everything works correct it gets a timestamp upon entering the system.

I started thinking about midi delay compensation again. I understand that it will be correct within the midi world but what if I send midi to a synth and get audio back?
I’m working like this a lot and it’s always a hassle because the timing always gets wierd in my current setup (non RME) and the delay is also different depending on buffer settings. Will this workflow be any smoother with built in midi in the UFX II for example?

I understand that the interface can’t do anything about latency in the synth but it could perhaps compensate for it’s own midi output and audio input?

Re: What RME gear gives correct delay compensation?

This depends on your DAW. Cubase automaticity adapts to the buffer size when you use an external instrument track (so it sends midi early, so it seems in time through the buffers), That is what I use mostly. Sometimes I just use midi and a mixer (so not through the computer), depends If I want to use FX in the computer, I also have some external FX (and some synths internal). When the synth track is finished I record it into the daw.
Also with RME you can use pretty low buffers like 64 ot 128 and that just sounds in time to me anyway. Except maybe a drumcomputer, but pads and synth leads rarely depend on super tight timing, and once I record it into the daw the issue is gone anyway.

Also no interface does anything about latency (only in your ideas lol) It just has to report it correctly to the DAW, which should do the rest. As I said I use cubase and that is fully latency compensated

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
Babyface pro fs, HDSP9652+ADI-8AE, HDSP9632