Arrival Time Differences In Preamps and Converters

[Studdy]

I will use my example but it will apply to any gear.
I do have everything sync and clocked properly.

I use a Rme Fireface. I have a few external preamps. Great River, Maudio etc. I also have a profire a/d converter.
I noticed that signals arrive in the daw at slightly different times. I use short cable runs and in most case everything shares the same snake. Has anyone else noticed that different preamps is resulting is un aligned tracks in the daw? Another example is when using profire standalone spdif into rme fireface. If i use the preamp line and the spidf at the same time the signal from the preamp direct out is delayed.
Anyone else dealing with this. Are most people doing a lot of time alignment in there daws?
Thanks.

 

[aortizjr]

Yeah that is because different converters take a bit longer to convert the signal. You can test this with a simple loopback test with a cable. Cable length doesn't matter since it travels at nearly the speed of light. It is all that conversion time.

In Cubase and I would guess most DAW's there is a setting for recording compensation by the number of samples. This is to help compensate for this problem. Most people don't even think about it and most of the time it doesn't really matter. Not to mention is kind of a pain in the ass to deal with it.

When you are dealing with individual tracking and such, you have to be pretty damn sensitive to notice that you are 1-2ms off.

To deal with it you can use the compensation in your DAW. If you have multiple brands of converters, then you have to use delay's on the input channels. It is a bitch, so I just am aware of it with things that have to be phase coherent, like OH's, or multi mic'd cabs and things like that.

There was a couple of articles about it on the web that I can't find right now. It is something very few seem to really care about, but maybe they should?

Let's just say that typically there are a lot of other things you are dealing with.

 

[Studdy]

Actually the digital signal arrives sooner than the preamp direct out. Which is why im slightly confused.

 

[deLuther]

AD/DA have group delay around 1-2 ms with modern converters.

 

[Studdy]

The digital signal arrives sooner than the preamp direct out. Which goes against what is being said here. Also there are time differences between interface onboard preamps and standalone preamps. This must be an issue for some people. I always place the mics where they sound good to my ears so I'm not being the visual guy, I just never really thought about time differences between preamps/interfaces because of my short/proper cable setup. I find it really weird that the profire spdif arrives into the daw sooner than its direct out mic pre into fireface. I would have thought the opposite I assumed sync/clock would take care of that. Just something I've never analyzed to death before. No biggy just wondered if anyone else deals or bothers to deal with it.

 

[tedtan]

The digital signal arrives sooner than the preamp direct out. Which goes against what is being said here. Also there are time differences between interface onboard preamps and standalone preamps. This must be an issue for some people. I always place the mics where they sound good to my ears so I'm not being the visual guy, I just never really thought about time differences between preamps/interfaces because of my short/proper cable setup. I find it really weird that the profire spdif arrives into the daw sooner than its direct out mic pre into fireface. I would have thought the opposite I assumed sync/clock would take care of that. Just something I've never analyzed to death before. No biggy just wondered if anyone else deals or bothers to deal with it.

The preamp direct outs still have to through A/D conversion before arriving in your DAW, though, so perhaps the RME converters have a slightly greater latency than the Profire converters (I'm assuming you are running the Profire analog outs into the RME converters for your comparison). You can try a loopback test through each set of converters to see if this holds true.

 

[Studdy]

Thanks for help thus far, but lets leave converters out of this for a second.

Im using the RME as main interface. Using the profire just as a standalone preamp. Connected to RME Line input via trs.

I put 2 brand new out of box (never opened) SM57s. I placed them side by side with the capsules identical. 2 identical cables. 1 going into onboard RME Preamp the other into Preamp on Profire. The profire signal is arriving in protools 59 samples behind. I checked with other outboard preamps (great river, maudio dmp3, etc) No sample differences from onboard pre's. So the only thing left is that the Preamps is the Maudio Profire in Standalone Mode have a pretty drastic delay. If use spdif out to fireface there is delay but not much at all, much closer. Can anyone else test this?

 

[Studdy]

bump.

 

[tedtan]

That's interesting, I didn't realize you were getting the delay even when running through the same converters. I can't think of any reason it should do that. Does the delay remain the same if you switch the preamps you run each of the 57s into?

 

[Studdy]

I really wish i had an answer for this one.

 

[aortizjr]

Thanks for help thus far, but lets leave converters out of this for a second.

Im using the RME as main interface. Using the profire just as a standalone preamp. Connected to RME Line input via trs.

I put 2 brand new out of box (never opened) SM57s. I placed them side by side with the capsules identical. 2 identical cables. 1 going into onboard RME Preamp the other into Preamp on Profire. The profire signal is arriving in protools 59 samples behind. I checked with other outboard preamps (great river, maudio dmp3, etc) No sample differences from onboard pre's. So the only thing left is that the Preamps is the Maudio Profire in Standalone Mode have a pretty drastic delay. If use spdif out to fireface there is delay but not much at all, much closer. Can anyone else test this?

Ok so the signal going through the profire in standalone mode is arriving later?

Almost all interfaces that operate in "standalone" mode that I know of go through an entire ad/da phase. There aren't physical switches that change it, it is just like an autosetting that happens in the DSP mixer routing the inputs to the outputs.

So one signal is going: Mic->Cable->RME Pre->RME conversion->DAW

The other: Mic->Cable->Profire Pre->AD->DSP Mixer->DA->RME Conversion->DAW.

That is where the additional latency is coming from. If you use the Profire SPDIF output, that is digital, and bypasses the RME converters and the Profire D/A. So the slight difference would be the input delay differences between the RME and Profier A/D.

Does that make sense?

So if you want to use these together and the phase matters and all that. Then you will have to delay the RME inputs by 59 samples. Essentially pushing them back to match up. Then set your daw compensation to 59 samples which I think pulls everything forward 59 samples as soon as you stop recording. Obviously some experimenting needs to be done here.

Cables and analog pre-amps should have no or very very little delay. They are electrons at nearly the speed of light. That's the beauty of analog.

 

[Studdy]

Thanks. But the only thing that makes no sense to me is how has everyone not had problems with all these so called "standalone" preamps? There are lots of different standalone a/d converters/preamps. API , maudio, focusrite , ,audient, etc. they all behave this way? I can't believe that the audient micro for example when being used as just a standalone "analog" preamp would have noticeable delay. Also what if you already have superior conversion there is no way around going through the converters? The units should just send a preamped signal out the line outs. Thanks for you explanation though.

 

[deLuther]

If you are using some interface as preamp, then, in most cases, preamp signal goes through DSP and D/A conversion, not just straight from preamp to analog output. If you need signal straight from preamp - go for analog preamp. Of course there is exceptions, but most interface does not provide analog pass through, if you need one - choose by studying detailed info/manuals.

 

[aortizjr]

Thanks. But the only thing that makes no sense to me is how has everyone not had problems with all these so called "standalone" preamps? There are lots of different standalone a/d converters/preamps. API , maudio, focusrite , ,audient, etc. they all behave this way? I can't believe that the audient micro for example when being used as just a standalone "analog" preamp would have noticeable delay. Also what if you already have superior conversion there is no way around going through the converters? The units should just send a preamped signal out the line outs. Thanks for you explanation though.

The profire isn't a standalone preamp, it is an interface that happens to have a standalone mode. Some of MOTU's stuff are similar. That's what I meant by interfaces, not standalone preamp/converters.

Others you mention are pre-amps that have a converter attached for convenience/marketing/whatever. So most of those do just send a line level signal right after the preamp and therefore no latency. Then the converter just splits off from the line level signal.

If you look at the block diagrams, that usually helps understand the routing.

 

[deLuther]

For example, take FireFace 400 and ProFire 610/2626, units have the same AKM AK4620 CODEC, A/D group delay at 44.1k is 43.2 samples, D/A group delay is 28 samples. So A/D+D/A=43.2+28=71.2 samples. Maybe mentioned FireFace is not FF400, so it can have different converter with shorter A/D group delay. And one should remember that additional conversion make result worse, even you will have top-of-the-line A/D conversion at the end of chain, so better to use digital connection to avoid additional conversion.
In case of FF800, you have ak5385 ADC and AK4395 or AK4396 DAC, ak5385 is similar in terms of quaility to ak4620, so no gain in quality. FF UFX has CS5368 ADC and PCM4104 DAC, CS5368 also similar to ak4620... but have group delay of 12 samples (shorter digital filter length, traditionally for Cirrus Logic converters, but it has it`s own shortcomings).

 

[Studdy]

So just dragging the audio back in time (or time alighn plugin etc.) is the only solution to this problem?

Thanks for all the explanations. I never knew that these All in One boxes induced substantial delay when used as a standalone preamp. Doesnt this kind of fall into false advertising?

Thanks everyone.

 

[aortizjr]

So just dragging the audio back in time (or time alighn plugin etc.) is the only solution to this problem?

Thanks for all the explanations. I never knew that these All in One boxes induced substantial delay when used as a standalone preamp. Doesnt this kind of fall into false advertising?

Thanks everyone.

I don't know if I would call it substantial delay. 1 ms is roughly the same as 1 foot of distance. Sure it may matter with like phase, but as far as playing and most everything else, it doesn't really matter. 44 samples 1 ms at 44.1 and that gets cut in half at 88.2.

I think most people don't give a shit and even for me I just know if I care to use the same converter. Converter quality differences don't make or break recordings by any means. Preamp wise, an internal preamp to an interface is typically just enough to get you by so it isn't like I would go out of my way to use a profire, motu, focusrite saffire, presonus, or even rme preamp. I am not afraid to use them, but I am not going to skip over my other dedicated pres that cost more per channel done DIY and sound better.

For the record, I run a MOTU interface with a Focusrite Octopre MkII and Behringer ADA8000 via ADAT, then a Mytek via SPDIF and there are still differences I have to deal with.

I would also argue that taking care of all this is part of the "engineer" in recording engineer that has been lost now that recording is easier. In the old days you had to calibrate the gain structures, perform regular maintenance, tape calibration, head alignment, etc. Basically someone had to know the gear in and out to make sure it was all performing properly and performing properly together.

Same is true for digital, but it mostly just works so you forget or no one tells you. But it is details like these and really knowing your equipment to know such things and make sure it is all working together properly.

And again, I don't consider it substantial by any means and I don't think companies need to advertise it compared to all the other things they gloss over or cover up. Hell most companies barely give you proper specs to a standard measurement, they don't give schematics any more and won't give them to you even if you ask. Also their shitty 1-year warranty, seriously!? Oh and "Zero latency internal digital mixer" yeah whatever... but it is close enough. Digital mixers have up to 12ms of latency!!

I think you should be proud of yourself for noticing and hearing it. Then learning something about it. Yeah it is a bitch. But maybe cascade a second RME via firewire instead of whatever reason you are using a Profire. Or get a proper dedicated preamp or use the ADAT's or something else. There are some benefits to using all one maker of converters/interfaces.

Also I doubt these slight delays are seriously ruining your recordings or performance. Hell standing up means your ears are at least 4 feet or so from the ground where most amps sit. So worry about it with phase or recording the same instrument. The rest, probably not a problem.

 

[Studdy]

So do devices like Focusrite Octopre, ADA8000, etc. All have this issue? Or are they "true" standalone preamps or do they go through the converter first inducing delay?

 

[aortizjr]

Most marketed as a standalone preamp are in fact that. So the Octopre mkii has analog outs and actually has no D/A at all. The A/D is just pulled off the line level outs. The Octopre mkii dynamic has a switch to use the direct outs from the pure before the A/D or from the Adat inputs. So no latency either in the right mode. And using the other mode would actually mean you would have to jumper the adat I/o.

Which brings me to the ADA8000. There are no direct outs, in fact to use it as a standalone preamp, you have to jumper the the adat I/o.