8.5 pro with UAD2 pcie - latency

I’m using an RME Babyface Pro USB with a UAD-2 USB OCTO Accelerator with Cubase 8.5 Pro on a Dell Laptop. Both the UAD and RME devices are connected on a single USB3.0 port via an Anker USB3.0 Hub (the Dell only has 1 USB 3 port!) This hub is recommended by UAD (if you must use a hub), and in practice I have absolutely no problems with this setup.

I’ve done a chunk of work to understand how system and UAD latency work together, and found practical steps to get it as low as possible when using UAD plugins. Here’s my findings. The good news in that you can get your latency as low as you like, if you understand how certain settings interact. So…

The UAD always has a latency that is added to the audio interface latency. To make this as low as possible, go into the UAD Control Panel → Configuration and untick the ‘extra buffering’ option (this is not required for most DAWs including Cubase). This only shaves off 64 samples.

Next turn ASIO Guard off. When ASIO Guard is off, the UAD latency is equal to the audio interface latency. e.g. I can set my RME latency as low as 64 samples, and with ASIO Guard off, the UAD latency is an additional 64 samples. The UAD latency will always equal the audio interface latency when ASIO Guard is off.

In pratice, ASIO Guard helps a lot when the project size increases. But it is best to set the ASIO Guard level to ‘low’ when using UAD hardware. With the ASIO Guard level set to ‘low’ the UAD latency will go as low as 256 samples. It will not go lower than this, even if your audio interface latency is lower. If your ASIO Guard level is ‘normal’, the UAD latency will not go lower than 512 samples.

For me, the sweet spot on smaller projects is to set the audio interface latency to 128 samples, set ASIO Guard level to ‘low’, and the UAD latency will be 256 samples. This gives me an actual latency of about 9 ms. And I can load up my OCTO accelerator to the hilt with minimal laptop CPU usage. On bigger projects, I’ll up the audio interface latency to 256 samples, giving me about 12ms latency (usable for playing soft synths live, but not ideal),

Of course I can go lower than this quite successfully by disabling ASIO Guard and setting the latency as low as 64 samples, at which point the UAD will add 64 samples, for a total latency of about 3.8ms. Or 128 samples (interface) + 128 samples (UAD) = 6.7ms. This is perfect for when I’m playing a few soft synths or jamming on my fav Native Instruments The Maverick piano, which I like to run through a UAD Shadow Hills Compressor and a Lexicon 224 Reverb… but that’s another story :wink:

Thanks!