Equipment Questions: Speakers, Amps & Mixers for DJ/PA

Posted: Sun Jan 28, 2007 10:32 am

Background:I've fallen into the fun world of ProAudio gear. I play Guitar, Keyboards and various other intraments and a month ago bought a Mixer to dump all the sounds into before sending to the PC for recording. The PC Speakers kinda suck, they aren't loud enough for me, thus came on my next project.

Equipment:
Currently I have a Alesis 8port Mixer, a few microphones and guitars and such. Included in this is a multitude of PCs (I'm an I.T. Director for a living) so I'm dumping a lot of pre-assembled audio through this system as well. My Newest purchase was a cheap Technical Pro LZ-1000 Amp, which lists it's stats as follows:

1000 Watts peak power
450 Watts @ 2 ohm
360 Watts @ 4 ohm
200 Watts @ 8 ohm
Inputs: XLR, 1/4", RCA plugs
Outputs: Speakon, Banana plug gold terminals
Dual Cooling fan
Iridescent blue LED meter
Clipping lights
Ground Switch
Dimensions: 19"W x 4"H x 9"D
(490 x 100 x 230mm)
Weight: 18 lbs (8.2 kg)
110-220V Switchable

Now, since I'm playing on using each "channel" on this amp as Right/Left, and having ONE speaker attached to each, I did my research and saw that qualifies as "8ohm" so I've been looking for speakers wired at 8ohm already. I found MANY cabinets ready to do the job, but now I'm stuck on wattage. I've been looking at 300Watt RMS speakers to attach to this.

Questions:
I know having an amp which has MORE wattage then the speakers can handle means my speakers are busted... So I was looking to OVERPOWER the speakers (200watt amp & 600watt rms speakers) attached to the amp to prevent that. During my discussions with people I was told by one that if I underpowered the speakers (i.e. 200watts through 600watt rms speakers) too much that it could be just as bad on the speakers as pushing TOO much power through them...

One of the other purposes for my overpowering the speaker RMS is I then can do two things. 1) Use the speakers in other situations (if I DO decide to use them in DJ/PA situation) and (2) I can upgrade my cheapy amp later to a higher wattage without replacing the speakers.

ANY advise is greatly appreciated. Thanks for allowing me to pick the brains of those who know.

Posted: Mon Jan 29, 2007 6:23 am

It sounds as if your informants are only giving you half a picture. The reason why it can be a bad idea to use an amp that is too low powered for the job in hand is that when an amp is overdriven, it clips. Clipping in a power amp output stage generates lots of harmonics at high power levels, and these can damage the high-frequency drivers in loudspeaker cabinets. So the recommendation is not necessarily to use amps of a higher power rating than the loudspeakers, but to use amps of a high enough power for the job in hand.

Your post started by talking about the "..fun world of ProAudio gear", but many would question whether the gear you describe falls into that category. If you try to get a setup both for monitoring of recorded tracks (i.e. studio use) and for PA, you are going to end up with equipment that does both jobs less than satisfactorily.

Fortunately, with this sort of setup you can upgrade each link in the chain separately as time goes on. As your usage changes, the shortcomings of different pieces of gear become more apparent, and it becomes time to address the new situation.

Keeping your present mixer, amp etc for the moment, what you could do is get some decent passive nearfield or midfield monitors for your studio use, and then hire or buy PA speakers when you need them. For live use, if you were to build up to having two 8 Ohm PA speakers per side, that would give you a 4 Ohm load per channel, which your amp would drive with enough power for small to medium venues. You would need to run separate cables back to the amp for each speaker to minimise cable losses.

In reality, you should be aiming to have different rigs for studio and PA use.

Posted: Mon Jan 29, 2007 4:27 pm

Exactly. You cannot get good results in the studio from big boxes designed for live performance. These are really apples vs. oranges.
For the recording gear, look at a small pair of powered ("active") monitors like the NHT MOO's, the KRK line, and there are many others in this category.Nothing big, bad, and loud, but very "neutral" so you hear what you're REALLY giving them. A pair of these types (I recommend the NHT's) will set you back a whopping $500.00. Mere pennies to a man in as noble a profession as yourself. Now to the live stuff...
DJ's are tough on gear-ALL of it- and unless you're out to start a small business with it, I'd steer clear of doing it. If you're thinking that you might want to do a bit of that work in the future, fine-RENT it for the occassional gig. Because decent quality live sound speakers are not cheap, will take up 88% of your garage (Muffy will NEVER get that Lexus in there now!), and will probably end up collecting more dust than bucks.
And, while we're at it, keep that Alesis mixer at home, too. Not only was it built to be used on a desk (not on a stage), it has few features that will fit a DJ's bill. Quick cueing, cross-fading, and input switching are hallmarks of a DJ mixer, not Firewire or a bunch of mono channel strips.
SO...first you have to decide on the applications(s) for your future gear.
You really didn't touch on that specifically. Do you want to play out live with a band? Were you wanting to do some DJ'ing because you meet some nice cuties at weddings?Not being sarcastic, but you really need to ascertain what you'll be doing with this gear. If it's just that you want something that's good for the music recording and that you could use it for live...think again.

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