Bunch of Carbon questions and suggestions

[dawnofdreamx97]

Hi ,

I have a bunch of questions about the carbon ,

I just received my carbon and have gotten it installed and setup with a brand spanking new Mac book pro 14" m1 max , 64gb ram. 2 tb hard drive. 24 core gpu. Still on Monterey OS and protools 2022.9

So far so good! All running smooth and behaving as it should.

Using the sonnet avb adapter to connect via Thunderbolt to the Mac book.

I'm currently using a midas xl48 via the adat ports for an additional 8 inputs. The only downside is that there is obviously a slight time difference between the built in preamps on the carbon / line ins , and the adat inputs from the xl48. I'm pretty sure this isn't a carbon issue , just the nature of the beast with this type of configuration.

My question is , does the carbon pre avoid this timing issue ? I'm assuming yes because its the same ADC and connecting via AVB and not adat. It's only an issue if I double mic a source and used 1 built in preamp and 1 preamp from the xl48.

Can anyone confirm this ?

I was just reading a thread below this that said they've added optical spidf support via the adat ports. Very cool !

My thought was maybe to use 2 channels of adat outs to feed a DAC / monitor controller via aes like my dbox+

Would be really cool if could put main LR outs to just 2 channels of adat outs / spidf and use the 2 additional analog monitor outs for more outputs not tied to main bus.

Is this possible ?

Would love to see a 8 or 16 out analog module that connect via avb like the carbon pre for additional DA ....

Would also love a way to knock the headphone outs down to line level to make them 8 line outs to feed headphone distribution system or just as additional line outs.

Also avid we need a better artist control app for adjusting headphone mixes. I'd love to give 4 musicians their own iPad and mix their own headphone mix in the live room .... just saying ! Kinda like the x32 q app

I track and mix at 96k mostly so the xl48 is occupying 2 adat input ports , will it still be possible to set 1 for spidf to do monitoring like I had asked above ?

Ok rant over lol ! Sorry about that !

[K Roche]

Whoa first thing you should do is downsize that photo image to maybe 840 px

beyond that I do not use any additional ADAT inputs so take with grain of salt

To clarify it sounds like you are saying that the signals coming thru the ADAT from the midas into PT are delayed compared to the signals coming through the Carbon inputs Yes ? All I can say I know a guy who is using a 3 party ADAT input MOTU I think, and he has not reported any delay issues

[dawnofdreamx97]

Originally Posted by K Roche

Whoa first thing you should do is downsize that photo image to maybe 840 px

beyond that I do not use any additional ADAT inputs so take with grain of salt

To clarify it sounds like you are saying that the signals coming thru the ADAT from the midas into PT are delayed compared to the signals coming through the Carbon inputs Yes ? All I can say I know a guy who is using a 3 party ADAT input MOTU I think, and he has not reported any delay issues

Sorry about that, I'll try to resize it.

So yes exactly. Not sure you'd notice the delay unless you had something double mic'd its Def very slight but it's enough to cause an issue. As I said though I believe carbon isn't the problem it's just the nature of having two different converters arrival times..... I'm thinking carbon pre will fix this but want a confirm before even considering it !

Happy new year all

[K Roche]

Originally Posted by dawnofdreamx97

Sorry about that, I'll try to resize it.

So yes exactly. Not sure you'd notice the delay unless you had something double mic'd its Def very slight but it's enough to cause an issue. As I said though I believe carbon isn't the problem it's just the nature of having two different converters arrival times..... I'm thinking carbon pre will fix this but want a confirm before even considering it !

Happy new year all

Well I can't say as I only use the 8 channels on my Carbon BUT is there not a way to clock both the Carbon and the Midas from just the Carbon perhaps in the Audio Midi set up ?

[dawnofdreamx97]

Originally Posted by K Roche

Well I can't say as I only use the 8 channels on my Carbon BUT is there not a way to clock both the Carbon and the Midas from just the Carbon perhaps in the Audio Midi set up ?

Yes I do have the midas clocked to the carbon and the results are the same.

[smurfyou]

Nothing to do with clock, you're correct that it's just the nature of two different conversion paths. Would only be an issue if double mic'ing across the two.

The question about the Carbon Pre is a good one if someone here can answer.

[Darryl Ramm]

Originally Posted by smurfyou

Nothing to do with clock, you're correct that it's just the nature of two different conversion paths. Would only be an issue if double mic'ing across the two.

The question about the Carbon Pre is a good one if someone here can answer.

Yep. this is what happens with outboard ADAT, S/PDIF, MADI, etc. converters. They are never going to just randomly have exactly the same hardware conversion latency as analog I/O on the main interface box. And while the Carbon is an unusual box it likely works the same as others and its driver reports back its latency to the DAW, but it reports the latency data for its onboard analog I/O. Systems could in principle report different latency for outboard converters, say through a different CoreAudio stream, except the interface had no way for the outboard converter to tell it what its input latency is, and I suspect no DAW really pays attention to different stream latency data. And for many uses the differences are small enough so they are just not noticed and/or are ignored... until its a phasing/interference issue.

This is one reason folks sometimes see small negative time offsets on tracks from outboard converters, if Pro Tools is compensating for latency for all inputs assuming they are the same, but if the ADAT or whatever outboard convertors have lower latency they will be shifted bavkwards in time compared to the analog input signals on the interface. This input delay compensation is not ADC (which is for plugins and hardware inserts), it happens transparently in all DAWs when you record a track.

You can deal with this at mix time by nudging stuff around, or using something like Eventide Precision Time Align as others have suggested on DUC in the past. (pity there is not a HDX DSP version of that tweaked for things like this, which could help here while tracking). If you have some alternative HDX DSP transparent delay you can control to very small delays you could try leaving that on the slower inputs.

When looking at any of these delays remember its not the RTL latency you measure in an RTL tool, that is output+input latency, you just want to measure the offsets in the two different recorded inputs.

I have no idea what the Carbon Pre does here, but I would hope Avid did line up the conversion latencies here. I also hope they fix the delay comp problems on Carbon that are affecting other users, and the several other embarrassing delay comp bugs in Pro Tools, not a good look for the industry leader.

[dawnofdreamx97]

Originally Posted by Darryl Ramm

Yep. this is what happens with outboard ADAT, S/PDIF, MADI, etc. converters. They are never going to just randomly have exactly the same hardware conversion latency as analog I/O on the main interface box. And while the Carbon is an unusual box it likely works the same as others and its driver reports back its latency to the DAW, but it reports the latency data for its onboard analog I/O. Systems could in principle report different latency for outboard converters, say through a different CoreAudio stream, except the interface had no way for the outboard converter to tell it what its input latency is, and I suspect no DAW really pays attention to different stream latency data. And for many uses the differences are small enough so they are just not noticed and/or are ignored... until its a phasing/interference issue.

This is one reason folks sometimes see small negative time offsets on tracks from outboard converters, if Pro Tools is compensating for latency for all inputs assuming they are the same, but if the ADAT or whatever outboard convertors have lower latency they will be shifted bavkwards in time compared to the analog input signals on the interface. This input delay compensation is not ADC (which is for plugins and hardware inserts), it happens transparently in all DAWs when you record a track.

You can deal with this at mix time by nudging stuff around, or using something like Eventide Precision Time Align as others have suggested on DUC in the past. (pity there is not a HDX DSP version of that tweaked for things like this, which could help here while tracking). If you have some alternative HDX DSP transparent delay you can control to very small delays you could try leaving that on the slower inputs.

When looking at any of these delays remember its not the RTL latency you measure in an RTL tool, that is output+input latency, you just want to measure the offsets in the two different recorded inputs.

I have no idea what the Carbon Pre does here, but I would hope Avid did line up the conversion latencies here. I also hope they fix the delay comp problems on Carbon that are affecting other users, and the several other embarrassing delay comp bugs in Pro Tools, not a good look for the industry leader.

Exactly my thoughts , hopefully someone from avid can confirm this. I would think it would be a much more pro and phase accurate sounding solution.

For me when tracking drums I'm usually around 12 inputs , so it would only be a few inputs. Hat. Ride , room mic, maybe a subkick ....

Would also love to dig in to my other comments posted in the first post as well as far as the optical spidf routing stuff, better artist control app and so on ....

[dominicperry]

1st of 2 posts - DUC won't let me post the full reply in one for some reason.

Originally Posted by dawnofdreamx97

I'm currently using a midas xl48 via the adat ports for an additional 8 inputs. The only downside is that there is obviously a slight time difference between the built in preamps on the carbon / line ins , and the adat inputs from the xl48. I'm pretty sure this isn't a carbon issue , just the nature of the beast with this type of configuration.

My question is , does the carbon pre avoid this timing issue ? I'm assuming yes because its the same ADC and connecting via AVB and not adat. It's only an issue if I double mic a source and used 1 built in preamp and 1 preamp from the xl48.

Can anyone confirm this ?

As pointed out by Darryl - you need to know the converter latency of both devices and trim/delay the longer ones.

I was just reading a thread below this that said they've added optical spidf support via the adat ports. Very cool !

My thought was maybe to use 2 channels of adat outs to feed a DAC / monitor controller via aes like my dbox+

Would be really cool if could put main LR outs to just 2 channels of adat outs / spidf and use the 2 additional analog monitor outs for more outputs not tied to main bus.

Is this possible ?

You don't have to assign the main outputs of Pro Tools to the main outputs of the Carbon. (You need to go to Setup -> Hardware) in PT and untick Main - Mon 1/2. You can then go into Setup -> I/O and decide which path you want for main Mon and select ADAT 1/2). [Watch out - if you remove the Mon inputs from this hardware tab, they become unattenuated, so full-scale).
Someone was asking in another thread for this to be hardware assignable - well, it isn't. But if you are using PT you can choose for ADAT 1/2 or S/PDIF 1/2 to be your main outputs (or Line1/2 or 3/4 on the analog d-sub). What you can't do is control that level from the main volume control - the digital output is always full-scale (as are Line 1/2 and 3/4). That doesn't matter if you are putting a proper monitor controller like the DBox on the end of a digital output.

Would love to see a 8 or 16 out analog module that connect via avb like the carbon pre for additional DA ....

It exists already. It's called the Carbon Pre! There's no DSP in the Carbon Pre - it's just a bunch of ins and outs and mic pres for a very unreasonable price. My bet is that there won't be anything smaller.

[dominicperry]

Would also love a way to knock the headphone outs down to line level to make them 8 line outs to feed headphone distribution system or just as additional line outs.

Also avid we need a better artist control app for adjusting headphone mixes. I'd love to give 4 musicians their own iPad and mix their own headphone mix in the live room .... just saying ! Kinda like the x32 q app

Dont' know how to address any of those points I'm afraid.

I track and mix at 96k mostly so the xl48 is occupying 2 adat input ports , will it still be possible to set 1 for spidf to do monitoring like I had asked above ?

I do everything at 96K too, and yes, I use the S/PDIF at 96k from the ADAT 1. The ADAT outputs are selectable individually as ADAT or S/PDIF. I don't use the inputs so I don't have any settings for those, but it doesn't look like you can use the Carbon ADATs as S/PDIF inputs from what I can see. Looks like the Midas is input only (you're not using it as 8 line outs??) so that isn't an issue. I'd use Word Clock to clock the Midas from the Carbon, otherwise you'll have to use the Midas as the clock source, which probably isn't optimal (not sure if the Carbon re-clocks to remove jitter like the RME interfaces do, but having the Carbon as master is better if it doesn't).

Ok rant over lol ! Sorry about that !

Not a rant, just questions. Hope that helps.

Dominic