Axe II + MOTU 828 + Mac: Setup Question

J

jshirkey

Experienced
I have my Axe II connected to my iMac via USB. I also have my Axe II L/R outputs going to two inputs on my MOTU 828. The main outs of my MOTU are connected to my monitors.

To play through the Axe II, I have been assuming that I had to have it connected to my MOTU directly, and then the audio would go through the MOTU and out to my monitors. It certainly works great that way.

But if I want to record (with Logic X), I discovered that there's a problem. I hear the audio that is sent through the Mac to Logic *and* the audio that is sent straight to the MOTU. The latency is different for each, and there's a kind of doubling effect.

I'm sure this is a complete noob question,but what's the fix? Do I disable the outputs to the MOTU? (Is there any reason at all to have the Axe connected directly to the MOTU?) If I just want to jam through the Axe II and not record, is it possible to do so without arming a track in Logic? I tried last night, and even though my Mac was getting signal from the Axe II, I couldn't figure out a way to hear any output (and I chose all of the different options in System Prefs/Sound). The only way I could hear the Axe II was to physically plug it back into the MOTU.

I feel like I'm going around in circles, and I need to start again at square one. (How to route/connect your Axe...). But if there is a simple solution, please let me know.

Thanks.
 
I don't have a Mac currently and have never used Logic but I do have an 828, and the basic principle is the same in all DAWs.

What you are experiencing is caused by the fact that you use both direct monitoring from your 828 AND monitoring from your DAW.

Just disable the latter. You really don't need to hear what your DAW gets UNLESS you are using effects for live processing.
 
vangrieg said:
What you are experiencing is caused by the fact that you use both direct monitoring from your 828 AND monitoring from your DAW.

Just disable the latter. You really don't need to hear what your DAW gets UNLESS you are using effects for live processing.
Click to expand...

I can't physically disable the connection to my Mac (obviously), so I assume I can disable monitoring by clicking some radio button within Logic? Since you don't use Logic, I know you won't have the exact solution I need, but that would be the gist, correct?

Thank you.
 
jshirkey said:
Since you don't use Logic, I know you won't have the exact solution I need, but that would be the gist, correct?
Click to expand...

Yes.

Here's one link: https://support.apple.com/kb/PH12934?locale=en_US

Generally, avoid software monitoring if you can. You get quite a lot of latency this way. If you absolutely must monitor in software, and since you have a card with S/PDIF, use that instead of analog inputs and outputs, that will reduce latency and improve sound quality by a lot. 828 is frankly quite a crappy card. You can tell by the fact that MOTU shies away from even publishing its specs properly. It's a glorified mixer, in essence.
 
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Think about it this way - when you plug your guitar into Axe FX, the signal goes through its input circuitry, a preamp and an analog to digital converter. These are by no means stellar to begin with. Just okay. Workable. If you then plug your Axe into your card's analog inputs, things get really messy. First, it all goes through Axe's digital to analog converters, again not really stellar. Each time you get latency, quite a lot of noise and some distortion. Then it all goes to your 828, to its preamp, A/D, then your computer's buffer, then D/A conversion again and then to your monitors via another amp. If you connect Axe digitally, you skip two conversion steps and two analog amp stages.

I don't know the exact Axe latency numbers, but I'd guess it's something less than 2 ms for A/D, 110 dB dynamic range, average distortion. Very fast, not too great in terms of noise and linearity, so you already lose something. Then your card will add some 7 to 10 milliseconds of latency round trip, or half that if you just use its D/A conversion only, and add about half the noise and distortion. So we're talking about 5-7 ms vs 10-15 ms latency and quite a big difference in terms of distortion and noise.
 
vangrieg said:
Think about it this way - when you plug your guitar into Axe FX, the signal goes through its input circuitry, a preamp and an analog to digital converter. These are by no means stellar to begin with. Just okay. Workable. If you then plug your Axe into your card's analog inputs, things get really messy. First, it all goes through Axe's digital to analog converters, again not really stellar. Each time you get latency, quite a lot of noise and some distortion. Then it all goes to your 828, to its preamp, A/D, then your computer's buffer, then D/A conversion again and then to your monitors via another amp. If you connect Axe digitally, you skip two conversion steps and two analog amp stages.

I don't know the exact Axe latency numbers, but I'd guess it's something less than 2 ms for A/D, 110 dB dynamic range, average distortion. Very fast, not too great in terms of noise and linearity, so you already lose something. Then your card will add some 7 to 10 milliseconds of latency round trip, or half that if you just use its D/A conversion only, and add about half the noise and distortion. So we're talking about 5-7 ms vs 10-15 ms latency and quite a big difference in terms of distortion and noise.
Click to expand...

I had my MOTU modded by Black Lion Audio a long time ago, so I think (??) some or all of the issues you mention have been taken care of in terms of its audio conversion quality. I forget the exact nature of the mods, but they were considerable.

Still, it seems like you'd suggest I connect to the MOTU digitally instead to reduce latency/distortion, if for no other reason. And--of course--I'm going to have to RTFM to see how to do that. lol And I shall...

Thanks again for all of your help.
 
I connected to the MOTU via S/PDIF. Things I learned in the process: 1. Had to change input source to S/PDIF on MOTU. (This also changed the input source in Logic to input 11). 2. Had to change clock setting to S/PDIF. (I was wondering why the Axe suddenly sounded really, really bad!). 3. Had to change sampling rate to 48 kHz.

And now I think I'm well on my way to having things figured out. At least for the time being. Thank you!
 
Turn off all your input monitoring in logic and only listen to the sound coming out of your interface. When you arm a track in logic you don't want the computer to send the sound coming into that channel back to the MOTU because it will come back with latency then combine to give you the "doubling" effect.

Disable "Software Monitoring" in the audio drivers preferences. Now Logic will not monitor signals through the mixer at all, leaving it up to your audio interface.

Another piece of advice would be to set up an "Aggregate Sound Device". See here on how to set one up:
https://support.apple.com/en-gb/HT202000

Then logic will see both the axe via usb and the MOTU as one sound card/device and you will have more inputs/outputs.

The advantage of this is it minimises the number of Digital to analog conversions (which aren't great as mentioned already). You can record the digital signal straight from the axe rather than converting it to analog (at the axe's output) going into the MOTU analog ins and converting it back to digital again to go into the computer...

When you record the axe the signal will be sent via the usb to logic but you will listen to the axe's output via the MOTU which will send it too the speakers without latency. You can also record the dry input of the guitar into the axe at the same time on another channel to re-amp later!
 
ralphonz said:
Turn off all your input monitoring in logic and only listen to the sound coming out of your interface. When you arm a track in logic you don't want the computer to send the sound coming into that channel back to the MOTU because it will come back with latency then combine to give you the "doubling" effect.

Disable "Software Monitoring" in the audio drivers preferences. Now Logic will not monitor signals through the mixer at all, leaving it up to your audio interface.

Another piece of advice would be to set up an "Aggregate Sound Device". See here on how to set one up:
https://support.apple.com/en-gb/HT202000

Then logic will see both the axe via usb and the MOTU as one sound card/device and you will have more inputs/outputs.

The advantage of this is it minimises the number of Digital to analog conversions (which aren't great as mentioned already). You can record the digital signal straight from the axe rather than converting it to analog (at the axe's output) going into the MOTU analog ins and converting it back to digital again to go into the computer...

When you record the axe the signal will be sent via the usb to logic but you will listen to the axe's output via the MOTU which will send it too the speakers without latency. You can also record the dry input of the guitar into the axe at the same time on another channel to re-amp later!
Click to expand...

I am now connecting my Axe to the MOTU via S/PDIF (see post above). I don't use the Axe's analog outs at all. So, should I still set up an aggregate sound device?

Thanks.
 
Didn't see your last post! sorry. Its probably not necessary to make the aggregate device unless you want to record the dry guitar at the same time for re-amping/tweaking the tone later
 
the doubling effect could mean you have two tracks recording at once, and not realizing it.. or.. i dont know
I have the same exact setup. Here's my
snWGdck.png
Motu setup which is working for me, not logic, but protools. Logic works though, i used it just the other day.
 
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