June 2006

Choosing a USB Audio Interface - Issue: June 2006

Choosing a USB Audio Interface
by Alec Watson

Computer recording keeps getting easier and more accessible.

Just a few short years ago, in order to do any “real” recording, one needed some kind of expensive internal controller card (and the guts to break open their computer to install it), a digital converter, and some good outboard microphone preamps; and we’re not even touching on the gear necessary to monitor your music. Today, there are so many choices for getting pretty darned good audio into your computer (at a good price) that it has once again become a little confusing when it comes to making the right choice. In fact, I was “Ebaying” last night and found a “Professional Engineer” who is willing to sell you his thoughts on purchasing the “right” USB audio interface. Not that I want to go denying dude his Ebay income, but as a little gift from CM to you, save your $16 US, (you can apply it to your new interface) here is what you need to know…

USB or Firewire?
I am almost certain I am going to get some hate mail from some better informed tech guy as to why I am wrong, but the honest truth is – it doesn’t really matter. That said there are a few considerations. No, USB and Firewire aren’t going to sound any different, but there may be some usage differences. If you have a computer that has all sorts of USB peripherals plugged in – printers, hard drives, card readers, USB Coffee Maker … and you have a Firewire port sitting empty, then it would probably be wise to go with a Firewire audio interface; you will never receive the dreaded “USB device not recognized” message AND you are likely to be able to achieve lower latencies due to less bus traffic … if that sounds like a bunch of techno crap, apart from the fact that it is (techno crap), rest assured I will explain it later so that you too can impress your friends!

On the flip side, I would tend to go with a USB interface if I was using it with my laptop. Yes, my laptop does have a Firewire port, but it also has six USB ports. A lot of the USB interfaces run off the power supplied by the USB port and as I don’t have a lot of USB peripherals plugged into my computer and I don’t want to carry a wall wart (power adapter) around with me, the USB interface is likely the more robust choice when it comes to powering external devices from my laptop.

Latency – What The Heck Is It And Why Do I Care?
Between the manufacturers of the USB audio interfaces there is a lot of hype about latency. Latency, in practical terms, is the delay that occurs between the moment your audio enters the interface, travels to the CPU (the main processing chip in your computer), is processed (effects and/or EQ that are applied to your audio), and then returns to your USB audio interface to be played by your speakers or headphones. Some USB interfaces have lower latencies than others; for me, however, any latency is too much! I prefer to “direct monitor”; most interfaces achieve zero latency times through this process. Direct monitoring really means that the USB interface is really splitting the audio into two paths, one path goes to your computer, the other goes directly to your headphones; the result is zero latency. The drawback is that you won’t be able to hear your vocal or guitar etc. with any of the cool effects that your computer can apply to them. For me, I would rather hear my voice dry than gooped up with effects and late.

Alec Watson is a Producer/Engineer that lives in Reno-hell Vancouver Island. He can be contacted at alec@alecwatson.com.

Stop The Bleeding - Issue: June 2006

Stop The Bleeding
by Jim Yakabuski

This is one of those things that hopefully only happens to you once in your audio lifetime, and if it does happen, you hope that it does so during a soundcheck and not during the show.

To communicate to the stage throughout the day, and to speak to the artist during soundcheck, we set up a ‘talkback’ mic that is routed through the snake to the monitor board so that the Front of House guy can have his voice magically appear in the monitors on stage. This useful process can considerably extend the life of a Front of House mixer’s vocal cords, as he or she doesn’t have to yell 100 feet to the stage all day long. The danger of having this mic is that if you happen to leave it on while you have the PA roaring away, there will be a ton of bleed back to the monitors and the monitor guy will begin pulling his hair out trying to find the root of the problem. This really is more of a warning to the monitor engineers out there, but the fault lies with the Front of House mixer. We all hate having our talkback mics shut off by the monitor guy because we are then forced to scream loud enough for someone to turn it back on. Therefore, we must be responsible enough to turn our talkback mics off out front so that the monitor guy can safely leave it turned on up there on stage.

The simplest solution is to get a mic with an on/off switch and always have it in the off position when you aren’t speaking to the stage. One simple rule of thumb that ensures that the show will not have this problem is unplugging the talkback completely from the mic cable before the show starts. The monitor guy should always have the talkback channel muted once the show begins, but this is an extra safety measure to ensure the front-of-house mix does not find its way back on stage.

This article is excerpted from Jim Yakabuski’s book entitled Professional Sound Reinforcement Techniques. The book is published by MixBooks, an imprint of artistpro.com. You can also find the book online at www.mixbooks.com and www.musicbooksplus.com.

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