Latency MBP built in audio faster than firewire?

[synthoid]

It's not so surprising that the internal soundcard would have a low latency. Being closer to the CPU and sitting on a more responsive bus than the firewire interface, it probably needs less internal buffering to guarantee a steady flow of audio.

Normally you buy an audio interface for more reasons than simply to outperform the built-in soundcard in latency; better converters, multiple inputs and outputs, other audio formats, different clock rates, etc. If the FA-66 doesn't offer anything more than the built-in sound card, then I'd agree that you screwed the pooch.

-synthoid

[valis]

If you are 'playing' any plugin instruments from external midi input that have a larger internal latency and have full PDC on you might notice considerable latency, though there are some extra features to work around that issue (enabling "Live" mode for tracks I believe will disable any high latency plugins in that signal chain).

Also firewire has an inherent latency that is higher than other types of soundcard connections, as the firewire chipset itself has a small buffer and some overhead (overhead which in theory should reduce CPU usage, although it seems that modern Intel chipsets are possibly faring BETTER with usb now.)

Lastly, Edirol isn't exactly the name that springs to mind when I think of 'the lowest latency possible' for soundcards.

[Timur Born]

Install "AU Lab" which is part of the developer tools on the Leopard DVD. It reveals all internal buffers and hardware latencies (AD/DA conversion).

Here's an example:

Input

HDSPe: Hardware 45, Safety Offset 24
FF 400: Hardware 45, Safety Offset 64
FF UC: Hardware 45, Safety Offset 24

Output

HDSPe: Hardware 79, Safety Offset 24
FF 400: Hardware 32, Safety Offset 64
FF UC: Hardware 46, Safety Offset 24

These are the latencies your interface begins with *without* audio buffers being added. So in the above example a Fireface UC with a buffer setting of 64 samples would sum up to 46 + 24 + 64 = 134 samples = 3.04 ms output latency.

These values differ from OS X to Windows because of how ASIO (IRQ) and CoreAudio (timer) work internally.

Input OS X vs. Windows

HDSPe: 69 vs. 32
FF 400: 109 vs. 45
FF UC: 69 vs. 55

Output OS X vs. Windows

HDSPe: 103 vs. 64
FF 400: 96 vs. 96
FF UC: 70 vs. 63

On the other hand OS X allows to set Audio buffers as low as 1 sample, while the minimum on Windows is 32 for PCI(e) and 48 for FW and USB (in practice rather 64).

[TC Custom Audio]

Originally Posted by Timur

Install "AU Lab" which is part of the developer tools on the Leopard DVD. It reveals all internal buffers and hardware latencies (AD/DA conversion).
...

Input OS X vs. Windows

HDSPe: 69 vs. 32
FF 400: 109 vs. 45
FF UC: 69 vs. 55

Output OS X vs. Windows

HDSPe: 103 vs. 64
FF 400: 96 vs. 96
FF UC: 70 vs. 63

...

This is the most informative post I've seen in a long time regarding the latency issue on native platforms.

Thanks for that.

As an aside, leave it to RME to FINALLY introduce a USB interface that doesn't suck.

[TC Custom Audio]

Originally Posted by Peedah1

I have just purchased a new unibody style MBP for music production. I've switched over after years of PC Cubase based 'almost right but not quite right' niggles.

I purchased a Edirol FA-66 firewire interface and am using logic 9. Here's the bit I don't understand - the built in audio interface is reporting faster latency than the FA-66. Surely this can't be right...

Yes, that's right. I'm a longtime PC user and I currently run Cubase with RME and Lynx cards. The built-in low latency audio on the macs is one thing that I really envy and I just don't think that's a feature that will be coming to the PC anytime soon. I bought Logic version 5 for PC and we all know how that turned out... But, maybe someday I'll finally get over it and buy a mac. If your mac has the 1/8" combo analog-optical jacks, then you've really got some serious options. Ditch the Edirol though.

[Timur Born]

It's mostly a problem of drivers. The inbuild Mac sound is just a plain Realtek HD audio chipset. While CoreAudio is made for professional audio on its own on Windows you either need software that makes full use of WDM Kernel Streaming or Wave RT or you need extra ASIO drivers (which Realtek does not provide).

You can easily get low latency audio from the Realtek by using ASIO4ALL on Windows though (which internally uses WDM KS). That even works inside a VM (Parallels better than Fusion) to some extend.

[TC Custom Audio]

Originally Posted by Timur

You can easily get low latency audio from the Realtek by using ASIO4ALL on Windows though (which internally uses WDM KS). That even works inside a VM (Parallels better than Fusion) to some extend.

Wow, I totally forgot about ASIO4ALL. Good point.