I’ve never actually put my finger on the issue until now. I guess I should have just asked you 10 years ago. LOL

I have a 2020 MacBook Air that I only use for HX Edit because I could never get MainStage to sound good because of what I attributed to a ground hum. I suppose I now start saving for a new MacBook Pro.

A ground hum would be a different kind of issue I think than fan noise - do you have the Intel or M1 (I think both kinds were available in 2020)? This sounds like it could be related to your audio interface setup, what are you using? You certainly should have the CPU power to run a MainStage rig as I still have a 2013 MacBook Pro that can run a live effects setup with many plug-ins at once.

The most critical part is an audio interface that gives you very low latency (aim for 5ms or less round trip latency). RME Babyface Pro FS is what I'm currently using and it's quite stable and very low latency (particularly for a USB interface).

I use the Stomp as the audio interface. I’ve actually been reading that others run it off a power bank rather than plugging it in due to the cable causing problems like this. I just thought maybe the fan was the cause after your comment.

My MacBook Air is the last Intel batch in 2020.

Got it. Even without the hum issue you would likely find it an unsatisfying experience using the Stomp as an interface for MainStage since the round trip latency would be quite high, well over 10ms in most cases, which is enough for the sound to feel disconnected from what you are playing.

The Stomp is capable of recording both dry and effected tracks over USB to an audio application, which is quite helpful (as you could apply different effects to the dry tracks afterwards), but in this case you'd be hearing yourself through the HX Stomp directly rather than the audio going to the computer, having effects applied in MainStage, then back to the audio interface outputs (there'd be a noticeable delay). For these kinds of applications I find that 5ms is the maximum acceptable round trip latency for an audio interface. RME, Apogee Duet, even some of the Focusrite Scarlett interfaces I think can handle something like this (but I recently auditioned a Focusrite Clarett+ 4Pre, a relatively new addition to their higher end lineup, and was surprised that it could not handle sub 5ms latency).

Now you have me saving more than a MacBook Pro...

Rob, I appreciate your insight into all of this. You were the one that got me into Guitar Rig all those years ago. As a bass player, I am often in orchestra pits in very tight quarters so I have always been a fan of the maximum tonal capabilities with the least amount of physical equipment.

Would I like to have a full analog rig of Analog Alien pedals and a Strymon Trio? Absolutely. But it's just not practical for my day to day. That was the appeal of the Stomp--tiny box, big speaker, bass and/or Stick--hooked up and playing. I had to help a guitarist load in to a pit one time. It was quite a sight and we had a built in space heater with all the gear he was pushing with his vintage tube amp. Sounded amazing, but vintage is heavy.

I had my little white MacBook with MainStage, a Native Instruments Guitar Rig Session I/O which is probably smaller than an iPhone pro max, an MKII midi over usb foot controller, and my bass. It all fit into my bass guitar case. I've been trying to keep that type of setup ever since. As the modeling has gotten better I honestly don't ever see myself using anything else unless it is a built-in fixture somewhere.

The only difference now is that I use the HX Stomp alone. Only editing the patches and practicing are done on the MacBook Air. When I do record the occasional clip there is a lot of airy noise and a distinct but faint hum. I will look into audio interfaces as you suggest. Working at the desk with my IEMs is really the best way for me to check out and learn material.

Thank you for the advice.
MM

One other thing - I just remembered that when the HX Stomp is connected to my MacBook Pro via USB cable, it can introduce noise if I use a USB hub rather than connect directly to a USB slot on the Mac, or my audio equipment is not all plugged into the same power outlet (i.e. possible ground loop).

Noted. USB-B to USB-C ordered. Thank you.

MM