I've been using computers for presentation in churches for a number of years now. Because the software we use (Media Shout in the past, ProPresenter currently) makes it easy to run video clips right off those computers and integrate it seamlessly into the presentation, that's what we've done. The downside of this has always been audio. Most computers have an extremely low quality audio output jack, that comes out as an 1/8" unbalanced jack. While this might be passable for headphones or computer speakers, it's problematic when integrating into a church sound system.
Unless the computer is near the soundboard, running an unbalanced line any distance creates problems. And because the output is of inherently low quality, it's already noisy. Sure, you could drop in a PCI audio card, but many of them also terminate in unbalanced RCA connectors. The answer is an external USB or FireWire interface. Enter the Lexicon Alpha. It's a compact entry-level USB buss-powered audio interface with bona-fide balanced outputs. We recently installed one in our presentation booth, and the sound quality is noticeably better. But before we get to that, let's take a look at the unit itself.
Input, Outputs and Controls
The Alpha is a model of simplicity. The front panel features a 1/4" instrument jack (unbalanced, for guitars, keys, etc.), two gain knobs (for the aforementioned instrument jack and the rear XLR mic jack), a Stereo/Mono button, a useful Monitor Mix knob (more in a moment), a Output Level control and an 1/8" stereo headphone jack. Two peak LEDs near their respective input controls alert you to overly hot signals.
photo courtesy of Lexicon
On the rear is a USB-B jack, two 1/4" TRS line-in jacks, an XLR mic jack, two 1/4" TRS line-out jacks and a set of RCA stereo outs.The TRS outs deliver a nominal +4 dBu. It's a snap to hook up and no software is necessary to make it work. If you want to access some of the additional functionality of the box, Lexicon includes Cubase LE for multitrack recording and mixing. Since all I really wanted to do was get clean, balanced audio out of my computer, I skipped the software.
photo courtesy of Lexicon
Having TRS, RCA and 1/8" outputs makes it very easy to send signal where it's needed in the right form. In our setup, I use the TRS outs to go to FOH, and the 1/8" headphone outs for the computer speakers in the booth. If I needed to, I could easily send the RCA outs to our DVD burner or other recording device.
Lexicon thoughtfully includes a 6' USB cable, so you don't need to go hunting for one. Since we're currently in transition between PC based presentation for CPC and Mac based for Upper Room, the ability to quickly change over from one platform to another by moving the USB cable is a huge plus. When connected to a Mac, it simply becomes another I/O device that you can select in the Sound Control Panel. The first time you hook it up, you need to tell the OS to route sound through the Alpha; from then on whenever you hook it up, it makes the switch for you (which I really like since we're using my MacBook Pro every week for ProPresenter).
Hooking up to a Windows-based machine is just as easy. The new hardware wizard proudly proclaims it has found new hardware and offers to install drivers. Since none are needed, dismiss the box and get back to work. Audio is routed to the Alpha automatically. This really is how Plug and Play is supposed to work.
Once audio is running through it, you turn the Monitor Mix control full-right and adjust your Output Level accordingly. That's it! For clean, quiet audio running to FOH over balanced lines, it couldn't be simpler. While I haven't had time to do extensive testing, the quality improvement is pretty substantial. The noise floor has dropped by 10-15 dB, and the increased dynamic range has added a noticeable punch to our soundtracks. Frequency response is quoted as 20-20KHz +0, -.5 dB, which is pretty respectable. It handles 44.1 and 48 KHz sample rates at up to 24 bits.
One thing of note for Mac users is that you can completely mute your alert sound volume without affecting the sound sent to the Alpha. This is handy for those times when the computer channel on the board is open and you do something to cause an alert beep. Unfortunately, I found this after I accidently triggered such a beep during a service. My pain is your gain.
Should you wish to use the Alpha for recording, it has a few nice features for that as well. The ability to connect line, mic and instrument sources is very handy. Obviously you might not be able to fit an entire band into it's inputs, but that's not the intended purpose. You could easily hook up a mic and a guitar however, and lay down some tracks. The Monitor Mix control gives you the ability to listen to the analog inputs directly (full-left) with no latency—very handy—or mix in the computer tracks as when doing overdubs. Since I didn't test the recording capabilities (that's not what I bought it for), I don't know the latency, or sound quality. I suspect the AD conversion is just as clean as the DA conversion however, and would make a fine addition to a small recording setup.
The Alpha also comes with Lexicon's famous Pantheon reverb VST plug-in, and acts as a hardware processor for said plug-in. This takes a load of your CPU when mixing. Lexicon is known for it's high-quality reverb and this alone could be worth the price of admission depending on your needs.
At a street price of just about $100, the Alpha to me seems a no-brainer. It's a great-sounding, simple way to get clean audio out of your computer and to FOH quietly over balanced +4 dBu lines. The fact that it's buss powered also makes it easy to install and even move to a remote location should you have the need. For me, the recording features are a bonus that I'll not likely use, but you never know. At the end of the day it does what I wanted it to do, and didn't break the bank.