Why is USB latency an afterthought in modelers?

[EOengineer]

Sorry this one is kinda long and probably pointless.

I’ll start by saying I LOVE tracking guitars through Helix hardware. The guitar input section in that unit sounds SO GOOD direct, even when driving other modeling software or reamping.

HOWEVER, as a live performer in an all direct/modeling band, I’m unable to use Helix’s USB interface because of its poor USB audio performance, with latency ~10ms in a modern Mac. I’m of the opinion that putting in the work to drop USB latency would open up some really cool workflows for tech savvy bands. Let me elaborate.

Our bass and both guitars use Helix and/or Tonex. We run XLR or 1/4 cables from each hardware modeler to a Quantum 2626 into Logic/Mainstage and monitor back out through an Aviom system. We do this weird hurdle because the Quantum is extremely low latency (< 3ms) and helps us feel more connected as a band. We can’t introduce the Helix into our OSX Aggregate device pool without tripling the latency. OSX’s aggregate devices always slow to the speed of the slowest device in the pool.

If Helix Stadium and other modelers had the same kind of USB performance as the Quantum, each band member could just run USB, cut out the extra DA conversion stage both coming in through the quantum, and likely get their monitor mix from the modeler as well, this also eliminating the need for the separate monitoring system and THAT DA stage too.

It’s probably too niche a case for mass appeal, most people aren’t gigging with a computer, but I love the idea of each band member basically bringing their own interface and monitoring setup.

 

[MirrorProfiles]

I KIND OF feel like aggregate devices are too flaky to rely on as a serious/robust option. I almost never use the built in audio interface features of guitar modellers (so I agree that they're not really up to par). Usually the limited I/O means there's some amount of routing juggling to do and I think that can lead to more issues than using the I/O in a caveman way. It's a bit of a waste of the USB features but I guess they're handy as a fallback in some situations. For band use, I'd either be doing SPDIF or AES, or just suck up the digital conversions (as they're generally not causing many issues).

If Helix Stadium and other modelers had the same kind of USB performance as the Quantum, each band member could just run USB, cut out the extra DA conversion stage both coming in through the quantum, and likely get their monitor mix from the modeler as well, this also eliminating the need for the separate monitoring system and THAT DA stage too.

I think this would be a great thing to achieve, but even if it was REALLY solid, I'd still be apprehensive about doing aggregate devices vs having a solid "all in" rig.

 

[Lysander]

The tl;dr is that there are a lot of moving parts involved when it comes to USB audio, to the point that guaranteeing low latency is but impossible
And this is the case even with dedicated recording gear, where getting low single-digit latencies involves battling with ASIO drivers and hardware settings.

I love using the HX Stomp for recording - it's a fantastic audio interface for guitar - but you're right, there's no way to track realtime audio through USB with it.

 

[EOengineer]

The tl;dr is that there are a lot of moving parts involved when it comes to USB audio, to the point that guaranteeing low latency is but impossible
And this is the case even with dedicated recording gear, where getting low single-digit latencies involves battling with ASIO drivers and hardware settings.

Yup, I totally agree with you. It’s challenging.

FWIW I have a couple very stable aggregate configurations with various devices that have worked well for me for a couple years and across OS updates. It could be total luck or anecdotal but I’ve felt like aggregate stability is better than it used to be.

None the less, get 5 devices together and who knows. It would be a crapshoot.

 

[LP59]

Sorry this one is kinda long and probably pointless.

I’ll start by saying I LOVE tracking guitars through Helix hardware. The guitar input section in that unit sounds SO GOOD direct, even when driving other modeling software or reamping.

HOWEVER, as a live performer in an all direct/modeling band, I’m unable to use Helix’s USB interface because of its poor USB audio performance, with latency ~10ms in a modern Mac. I’m of the opinion that putting in the work to drop USB latency would open up some really cool workflows for tech savvy bands. Let me elaborate.

Our bass and both guitars use Helix and/or Tonex. We run XLR or 1/4 cables from each hardware modeler to a Quantum 2626 into Logic/Mainstage and monitor back out through an Aviom system. We do this weird hurdle because the Quantum is extremely low latency (< 3ms) and helps us feel more connected as a band. We can’t introduce the Helix into our OSX Aggregate device pool without tripling the latency. OSX’s aggregate devices always slow to the speed of the slowest device in the pool.

If Helix Stadium and other modelers had the same kind of USB performance as the Quantum, each band member could just run USB, cut out the extra DA conversion stage both coming in through the quantum, and likely get their monitor mix from the modeler as well, this also eliminating the need for the separate monitoring system and THAT DA stage too.

It’s probably too niche a case for mass appeal, most people aren’t gigging with a computer, but I love the idea of each band member basically bringing their own interface and monitoring setup.

It's not an afterthought. The problem is modelers do more processing than an audio interface and must use larger internal buffers because of that. That means higher latency. Your Quantum does even less than the minimal processing that most audio interfaces do and that's why it uses extra small buffers and has such low latency.

I'm assuming you know you can use the Helix driver to lower the latency compared to class-compliant, but it will still be higher than what you get with an audio interface.

And I'm assuming you know you can turn up the sample rate and turn down the computer audio buffer size to minimize the latency. In other words, spend computer CPU to lower your latency.

SPDIF might be worth checking out, because it's not a buffered protocol, but you'd have a hard time finding an audio interface that can manage more that 2 SPDIF connections.