Band buying PA - advice

[Stormbringer]

Hi all,

My band is looking into getting a PA for practices, and could do with a little bit of advice cos we're not really savvy on these sorts of things. We want something cheap/bottom-end just for practices, not gigging or anything - basically the minimum needed to get three vocals and maybe a keyboard up to the level of our hard-hitting drummer. So we've been into shops and on trademe hoping to learn a bit about what's out there that we might be interested in, but some advice on the following would be helpful:

Power: we just need to get three vocals above the drums in a garage or medium sized room, no big pubs or anything, and because we're wanting to save money and space we want as small as we can go - how powerful does it need to be?
(We have to ask because we got the distinct feeling the shop guy was trying to upsell us into something bigger than we needed)

Related to this, looking at PA stats some give a straight wattage, like 200W, some have funny things like 2 x 120W etc - can an electronicstician fill me in on what the latter means?

Next Q: If we want to go the way of piecing together an amp, speaker and mixer ourselves, in the small-PA industry is there serious risk of different bits being incompatible and blowing up, or is it pretty much plug it all into each other and it'll probably be fine?

Thanks

[Timi]

Theres 3 ways of doing it.
Mixer -> Powered speakers
Mixer -> Amp -> Passive speakers
Powered mixer -> Passive speakers

The first two can easily added to, but the third is usually more limited.

For the first two you should really have a 31 band eq between the mixer and amp so you can tune the PA to the room (better sound quality and less feedback). Some mixers have a smaller 5-9 band output eq on them which is better than nothing but obviously not as precise as a 15 or 31 band eq. Most powered mixers don't have the ability to allow you to run an outboard eq to tune the PA. Most usually have a 5-9 band output eq, which is better than nothing but not ideal.

Another issue is channel inserts for running things like compression. Most mixers bigger than a laptop size will have inserts, but most powered mixers don't. Slight compression on vocals smoothes them out and can also help not to blow things up if you drop a mic. I wouldn't want to use a PA at practice for vocals with no compressor personally.

As far as not understanding why some are 200 watts and others are 2x 120 watts, the 2x means its a stereo (2 channel) PA. Only really small PA's based around a powered mixer are usually mono.

If you are wanting to clearly hear 3 vocals and keys over a loud band I think you should be looking at some higher power ratings. I don't really know about what kind of power you need, but just keep in mind that companies rate their powers differently and that lots of power into a cheap inefficient speaker won't be very loud.

[Stormbringer]

Thanks man, very informative, I'll take it all under advisement!

[nzsimon1]

what is the maximum you can spend ?

The KB uses a lot of bottom end power as they have a large dynamic range and can swamp vocals I take it the KB player has no amp ?

As a bit of an understanding of power a drum kit is acoustically around 400 watts give or take depending on the kit and the drummer

[Timi]

As a bit of an understanding of power a drum kit is acoustically around 400 watts give or take depending on the kit and the drummer

?

[nzsimon1]

meaning a drum kit is roughly equivilent in volume to a 400w speaker in SPL output

So a recording of a drum kit played through a 400 watt speaker would be about the same volume as a actual drumkit in the room

Or looked at a different way yopu would need about 400 wats of vocals to overcome the volume of an unmiced drum kit

All roughly speaking of course the peak spl of a drum kit can be over 150db spl or in laymans term very loud

[Timi]

I know what you are trying to say, I just think its silly. As silly as saying my cat has a 10 watt meow, my scream is 25 watts, and I can do a mean 5 watt fart.

The actual SPL output of a "400 watt speaker" can differ wildly. Its the SPL that you should be looking at rather than ambiguous power ratings, and I very much doubt a drum kit can put out over 150dB.

[zdali]

I know what you are trying to say, I just think its silly. As silly as saying my cat has a 10 watt meow, my scream is 25 watts, and I can do a mean 5 watt fart.

The actual SPL output of a "400 watt speaker" can differ wildly. Its the SPL that you should be looking at rather than ambiguous power ratings, and I very much doubt a drum kit can put out over 150dB.

That sounds like a challenge... Anyone got a noise-o-meter?

[Timi]

I do, and have never seen anything near 150 on a kit.

[thehenderson]

I know what you are trying to say, I just think its silly. As silly as saying my cat has a 10 watt meow, my scream is 25 watts, and I can do a mean 5 watt fart.

Haha great post!

I agree though, I don't think putting a wattage to acoustic sounds makes things easier to think about. SPL can be helpful as a point of comparison, me and timi sat around screaming into his SPL meter. Screams are loud

[Stormbringer]

what is the maximum you can spend ?

The KB uses a lot of bottom end power as they have a large dynamic range and can swamp vocals I take it the KB player has no amp ?

As a bit of an understanding of power a drum kit is acoustically around 400 watts give or take depending on the kit and the drummer

He doesn't have an amp for it, no - Keys are a more casual addition to our sound, played only occasionally by the other guitarist.
As for what we can spend, it's a difficult question - we went into this not knowing how much cheap PAs cost. Having looked on trademe and in stores and bearing in mind the three ways Timi mentioned, I would tentatively answer the question with one of my own: What can you get for $500, and how much beyond that would we need to go to hear ourselves?
Doesn't need to sound good, and we only want what's necessary lol, sort of a bare minimum. Did I mention we're mostly students? Can you build PAs out of road signs/cones?

[rickenbackerkid]

I do, and have never seen anything near 150 on a kit.

I have, but the meter was within a meter of two of the drums. As your ears would be in a small garage.

[rocklander]

I do, and have never seen anything near 150 on a kit.

I have, but the meter was within a meter of two of the drums. As your ears would be in a small garage.

and as a muso on stage... don't my ears know it it's not the drums so much as the cymbals though.. ouch!

[sgt mukuzi]

get 2k off ya mum and call jands

[Stormbringer]

Haha yeah, the old Pink Floyd trick -
Nick Mason: 'You see, when Syd left we went to David's mother and we said "look, we'd like your son to join the group - you'll have to front a lot of equipment." And, I mean, that's how we got all of our equipment!'