Can I use Latency Compensation Info to buy laptop?

Edit: I’m talking about using laptop’s with their default soundcards, without plugging in audio interfaces or anything like that

On this laptop (as well as all non-mac laptops I’ve used) I’ve never been able to get latency below 100ms no matter the settings, no matter the software (including operating system), which led me to believe it was a hardware thing with non-mac laptops.
Until now I didn’t know there was a name for that. I just learned from Ardour’s toolbar this irreducible hardware latency is called I/O latency.
Ardour reports that the I/O latency of this laptop is about 98ms which is consistent which what I’ve been experiencing.

So I was wondering, if I was to get a new laptop (or a windows computer) for live playing would it be a good idea to use Ardour as a latency benchmarking tool of sorts, in order to buy a laptop that doesn’t have a crazy high I/O latency like this one?

I would simply install Ardour, enable the latency compensation info toolbar item, look at the I/O latency and discard any laptop showing anything higher than 20ms


The latency that Ardour reports there depends on 3 things:

  • The buffersize and samplerate set in Window > Audio/MIDI Setup
  • Any plugins that add latency
  • Any systemic latency, configured or measured in Window > Audio/MIDI Setup

You can reduce the latency by picking a smaller buffersize in the Audio/MIDI Setup.
The problem with that is, that a too small buffer can cause dropouts if the system cannot keep up.

The reported latency by itself is not a useful indicator, you want to know that the system can also sustain that low latency over longer periods of time.

While there is a hardware dependency (e.g. WIFI Chipset, USB chipset, graphics-card), see The Ardour Manual - The Right Computer System for Digital Audio in the vast majority of cases the problem is software; specifically system configuration.

It is not just Linux, on WIndows there are also countless steps to make a generic OS more suitable for pro-audio.

Tweaking the system requires a bit of expertise, which is why there are many Pro Audio Distributions like AVLinux or KXStudio, UbuntuStudio etc.

Have you tried to run one of those?

I didn’t mention that I’m looking at the reported latency on a blank sesssion, no plugins or anything, at the default 44.1 khz / 1024 samples, which ammounts to 23.2ms according to the Audio/MIDI setup window.
Substract 23.2 from 98 and that leaves 74.8ms of irreducible latency
EDIT: actually, if I try setting buffer size to 64 (which reduces Ardour’s latency to 1.5ms), the I/O latency is still over 90ms, not 74.8, so what’s going on?

That only applies to the 23.2ms. Correct?

What I found in the manual is that I/O latency is small enough to be neglectible for PCI devices, so perhaps the internal audio card of this laptop is not PCI? I don’t know

I would have to check out the latter two, since I know AVLinux is a very big download.
But why do Macs never seem to have this problem? Even with old Macs I’ve used, latency has never been a problem

More importantly, if I tried one of those distros and the reported I/O latency by Ardour was still this high, that would most definitely mean that it’s a hardware issue. Correct?

Macs don’t have this problem because Apple fully controls the hardware.

You can use the audio/MIDI setup dialog with a loopback cable to measure the hardware latency. It is not distro or OS dependent (with some minor, mostly unimportant exceptions).

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Alright, so I just did the test with the cable and the detected roundtrip latency is over 6000 samples (140ms), so I guess this laptop’s toast for live playing and I should test with another laptop, right?

What are you using for an Audio IO device? Also which driver are you using on Windows, ASIO or MME? If the latter, you should be using ASIO and an ASIO compatible audio interface, as that is definitely the best way to get decent latency on Windows (Going back to what was mentioned earlier about system setup, as there is a lot of tweaking to be done for audio on Windows)


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