What size amplifier & PA to use?

[rpe]

I apologize if this sounds stupid. Is there a formula for computing what wattage is necessary for guitar amplifiers and PA systems to be compatible? I know the size of the venue is a big consideration but just suppose a band is playing in a small club (30 tables, small dance floor, bar area) playing mild rock with lead guitar, rhythm guitar, drums and vocalist. What is the optimum wattage for the guitar amps and PA to be compatible and equally heard? I guess a 40W Crate is not going to hang with a 100W Marshall stack and a 30W PA system for the vocalist is not going to compete with either. How does one compute what is required.

Thanks,

rpe

 

[muttley]

For a basic house P/A, I would start with a pair of 250 watt or so speakers E/V, or JBL ,or EAW, with a 400 watt per channel amp, if this is " too big/loud " ,one can always run it at lower volumes.
There is no real formula to figure, have your sound man/trusted pair of ears listen, then make necessary adjustments to volume as needed, every venue is going to be different, there will be times when you feel that its not loud enough, but one plays on anyways.........



da MUTT

 

[Tulago]

OK...I'll weigh in here to start a very subjective answer. There is no formula.

My two cents is you should get an amp tone you really like and run that through a PA system. You don't need a lot of power in your amp necessarily. Some prefer a 30 watt Fender Champ or a Vox AC-30 driven just to the breaking point. Run that through SM-57 mic just touching the grill cloth to a good high quality PA and everyone in the band will be happy. Your tone is preserved and the front of house can set volumes according to the house specs...ie; size and accoustics of the venue.

A good PA gives you lots of flexibility whether you're inside a room or outside at a music festival. If an amp blows a fuse you can run anything through a PA. You can insert outboard processing such as compression for the vocals and delay for the guitars...also you can route the signal to mains, monitors and recorders. I suggest a minimum of 300 watts going to two 15 inch speakers with high frequency compression horn drivers. Guitars, bass, and vocals can all live in there at the same time.

 

[eeldip]

lots of variables here, but speaking from experience...

i have one of those jbl powered eon15 jobbies. and my band plays similar sized venues. it seems to work pretty well. it is very portable, has a built in amp (saves time setting up the PA, saves cords, makes things simpler in the murphy's law world of live music). totally loud enough to compete with guitar amps and drums. (placement is important. speaker stands are vital) and they take a lot of abuse. dont buy the soft gig bag that comes with them (mine ripped apart after only a few shows). get a serious case, or just fuck it and let them get banged around.

i have also used those powered mackies. they are much better sounding (and louder) than the JBLs, but cost almost twice as much. consider those as well.

also, you will want to look at a small powered floor monitor...

 

[TexRoadkill]

I would agree that 300w and 15" speakers is the MINIMUM for a PA system. I would put the minimum wattage closer to 500 per CH but preferably 1000 per CH if you are going to put anything but keys and vocals through it.

I've never had to mic a guitar amp for any place that was smaller than 300 people unless the amp is seriously underpowered. A good 30 watt tube amp is ear shattering at full volume.

Bass frequencies take exponentially more power in a PA system. If you are planning on running bass through it then you must have some good power.

 

[muttley]

Lots of variables because of lots of experiences here.........



da MUTT

 

[eeldip]

My two cents is you should get an amp tone you really like and run that through a PA system. ...Vox AC-30 driven just to the breaking point. Run that through SM-57 mic just touching the grill cloth to a good high quality PA and everyone in the band will be happy.

those are fucking loud amps! i think the beatles used them in theaters unreinforced!

personally i prefer the sound of non-reinforced amps. way better tone. also, i think they have a better sense of place in the venue.

 

[TexRoadkill]

those are fucking loud amps! i think the beatles used them in theaters unreinforced!

I can believe that. We recorded a Vox AC30 and a little Fender Blues Jr over the weekend and both were at top volume. It was mind numbingly loud. Luckily my my sennheiser cans have great isolation so I could safely walk around the room.

 

[Tulago]

You guys are right (as usual)...

I realize watts and volume don't follow a formula. What I meant to say was go for tone at whatever volume you find it and, if necessary, you can amplify it for house reasons.

Personally, I believe 30 to 50 watts is more than adequate for most of what I like....and it can stand alone without a PA.

I alos happen to like the Pod Pro through the PA for alot of different amp tones...lots of flexibilty with some tweaking.

 

[Jblount]

I agree with tex, anything smaller than 300 wats, is to small to be versatile. Go large for just a few dollars extra. Nothing sounds better than knowing that you have the system backed down so that there is hardly any stress on the amps and speakers. I enjoy making a pa efficent enough to run at half volume or less, knowing that if you needed the extra power for volume and low frequencies, it is there!

 

[rpe]

Thanks everyone. I appreciate your feedback.

rpe

 

[mm2k5]

my band has 4 sets of duel 15s....8 15 should be loud enough just about anywhere you play