Monday, June 30, 2014

Live sound

This post is a description of my system., and most of the rationale behind it.
It's slightly out of date, but I'll do an update soon.

I've been into live sound for quite a while now. A few years ago I did the audio for the Strawberry and Harvest festivals in the Northern Neck. Last year I showed a movie outdoors to our swim team, and that was a lot of fun for everyone. I also did some sound for the local Bible Bee.

Last year my sound system consisted of a Zoom HD16CD 8 ch recording mixer, two of the cheapest 12" PA mains I could find, a Bose home theater subwoofer, a QSC RMX 1450, and various cables and mics.

I really like the mixer for recording. I got it used for $300, and I haven't seen anything before or after, new or used that rivals it for anywhere near that price. This comes close, but doesn't have an option to use it as a control surface, which is almost a necessity when doing serious recording.

The PA mains were Gemini 1204's. I wasn't expecting hi-fi, which was a good thing. I used a lot of EQ and processing, and eventually managed to get them sounding O.K. with a subwoofer. The subwoofer had trouble keeping up at high volumes, but actually did surprisingly well for what it was (two 6" drivers outside) I'm not really a fan of Bose, they're not usually the best option, but that was what I had available at the time. It was something like this

The amp is a good solid class AB amp, built very strongly. It weighs about 40 lbs. I talked to a number of people, and all the feedback was very positive about these amps. I also found a service manual for it, which I really like.
http://www.loudandclearproductions.com/library/QSC.pdf

Anyway, when I did the outdoor movie, I had to turn the amp up all the way, the clip lights were blinking, and I still wished I had a little more volume. (I showed Cars) So, I figured if I wanted to do it again next year (I did!) I should upgrade my sound system. The amp I was using was 280 watts/channel, and the speakers I have are only rated for 100W RMS. I don't like running things like that, especially with the way things are compressed nowdays.
I started looking around, and all the options looked expensive. About the cheapest step up I could find was some Yamaha speakers, and I'd still need a subwoofer to keep up with them. Subwoofers are expensive too, when I was looking, anything that looked plausible was north of $500...
I decided that wasn't happening. Maybe I could build some speakers... I searched around some, and came across this website: http://billfitzmaurice.com/
I looked through all the designs, and specs, and decided that these were much more attractive options.
When going through the used section, I found an ad for 2 T48's and a DR250 'make me an offer'.
So I did. Suffice it to say he just wanted to free up some space, and I was happy to help him out with a total cash flow of a bit under what one of the commercial subs I was looking at would have cost. Win-win!

The subs work great so far, and the DR is very efficient. I have been somewhat disappointed in the bass and mid response of the DR though, it has tended to sound rather shrill on its own. It is a significant improvement over what I had though, especially properly crossed over to the subs. On its own it doesn't sound bad with a little EQ, but it does need the EQ. (I'm still quite happy though, considering the price I paid)

Currently the way I'm thinking I'll get things set up is:
QSC amp for the subs,
GTD audio TN-350 for the tops
DBX Driverack PX, or PA+

The reason I'm looking at the GTD audio amp is that it's the only sub $1000 1RU amplifier that I could find that has enough power to drive my speakers to full capacity.
I'm going for 1RU because I have a 4 space SKB rack case, and I want the system processing and amps to all fit in that.
If I really wanted to have a compact electronics system, this would be very attractive:
http://www.carvinguitars.com/products/DCM2004LX
It won't bridge into 4 ohms though, and it doesn't quite have enough power to drive my subwoofers to their max. Not that I plan on running them up to the max, but I'd want to be able to, if nothing else, so the amplifier doesn't have to work as hard. (Of course, if I really needed compact, there's also Powersoft, but I'd rather pay for a semester of college for that much money)

Part of the reason I'm working on all this (other than that it's fun) is that I'm hoping to have a rig that I can rent out this summer. Still needs a little work...