NEW: Breakaway Broadcast Processor ASIO 0.90.79

Hi Guillou!

As always, there is no single easy answer!

What I/O do you need? How many channels?

For example, EMU Tracker Pre is a nice cheap external USB interface, and it handles 192 kHz well enough for MPX output, but it’s only 2 channels! So, you have FM Stereo MPX out, and MONO studio ultra low latency out, and that’s it.

I have not personally used the EMU Tracker Pre.

I have an EMU 0202 USB, and audio performance is good, but it usually fails to initialize when starting the computer, so I would not use it for unattended applications. Also it’s still only 2 channels.

I have an EMU 0404 USB, and it works well, but it’s also just 2 channels.

I have an Edirol FA-101 and Edirol UA-101, and they both work well. These are 8-channel cards, so you have enough I/O for everything.

However.. NONE of the above interfaces will give you exactly buffer size 256 or 512! They give you many other sizes, but not those too. And that’s too bad, because those are the sizes used internally by the algorithm. It will run fine on a different buffer size, but CPU usage will be more uneven, so you may need a faster CPU to avoid glitches. Also latency will be a tiny bit higher, because it must still buffer to meet the internal buffer size.

Also, don’t forget that external interfaces are more expensive than PCI cards for the same audio performance. If you’re building a dedicated PC (which you should be, they’re so cheap), I recommend you buy an internal PCI card, and get the lowest possible price AND lowest possible latency.

Best regards,
///Leif

ESI Juli@ is nice! I don’t have one myself, but I’ve used it, and I can definitely recommend it.

It has 2 analog and 2 digital channels (single spdif). So, using only analog, you get FM Stereo MPX (17ms latency), and a mono ultra low latency studio output (8ms latency) to drive headphones, if 17ms is too slow for you to comfortably monitor. If 17ms is fast enough, just monitor off air. If you have a D/A converter which can handle 192k S/PDIF, you could get stereo ultra low latency output too.

You can also of course run in full quality mode, for 500ms on-air latency, and still have the 8ms low latency output.

///Leif

ESI Juli@, M Audio Audiophile 192, Marian Trace 8, and LynxTWO will all yield basically the lowest possible latency, with buffer size 256.

Smaller buffer size than this could be a little bit faster, BUT, the internal buffer size of the algorithm is actually 512 samples. So, for ASIO buffer size 256, the program must buffer up two blocks (so that it has 512 samples), and then process ALL those 512 samples in the time of just ONE 256 sample block, so that it can output the first of those 256 samples during the current time period instead of having to wait for the next one. This means you need a faster cpu to run buffer size 256 than what is really necessary for the algorithm, because you need some headroom.

If we used buffer size 128, it would be slightly faster — (latency might be 15ms instead of 17ms) — but you’d need a much faster cpu, because now the CPU must process 512 samples in one 128-sample time period (and sit idle for 3 periods until it has the next 512-sample block!)… Unfortunately due to the nature of my clipper algorithm, it cannot be broken up into smaller buffer size without compromising audio quality.

Please note that this applies only to BBP ASIO.

Breakaway Live does not use the clipper back-end, and can use ANY block size down to 48 samples without uneven cpu load or extra latency. It does not have to be an even multiple of anything.

Marian Trace 8 is a nice card. 8 balanced analog inputs and outputs, DC STRAIGHT outputs (!!), and 192 kHz support. This card is ideal for an FM processor. It is quite a bit more expensive than ESI Juli@ or M-Audio AP192 — Trace 8 is €399 — but you get what you pay for. DC straight outputs means no tilt adjustment. It’s a different grade of card from pro-sumer ESI and M-Audio.

That said, ESI Juli@ and M-Audio AP192 are a great match with BBP ASIO.

Best regards,
///Leif