Will I break my PA Speakers?

Paligulus

hi Folks,
I posted this question in Instruments (so appologies if it looks familiar!!!)but I think its more suited here!!!

Awhile ago I bought a 1000 Watt PA system. I then bought two PV 300 Watt speakers. The reason I got the 300 Watt was because I couldn't afford the 500Watt (!) and I was only using the system for practicing with no intention of gigging. So there was no fear of me pushing the PA to blow the PA speakers.

Now I will be using it for giging soon. It wont be a full band with drums so there wont be a need to push it (acoustic instruments) 300 Watt speakers or do I run the risk of blowing them if I turn up the volume too loud? (over half way?)

If I do run the risk of blowing my speakers what would be the best/cheapest option? Getting Bass bins or trading in my 300Watt speakers?

Cheers

Savman

Can you post:
-Poweramp (or Powered desk) rated output at 4 and 8ohms
-speakers full power handling rating, should be written like 300w RMS/600w Program/1200w peak

You should be grand, but best to be sure.

Paligulus

Savman wrote: »

Can you post:
-Poweramp (or Powered desk) rated output at 4 and 8ohms
-speakers full power handling rating, should be written like 300w RMS/600w Program/1200w peak

You should be grand, but best to be sure.

Cheers. Definately wanna be sure cos the guy where I was buying them said I could blow them. Of course, he was trying to sell me the 500 watt speakers!!!!!
Here's the mixer:
http://www.soundcraft.com/product_sheet.asp?product_id=129
Outputs:
Max out main / mon = 18 dBu
Power Output = 2 x 500W into 4 OHMS


Speakers:
Peavey PRO -15
Impedance=4 OHMS
Power 600 Watts Program


Is that enough? I dont have the manual for the speakers,

Cheers

PaulBrewer

...but don't quote me on that!

Normally the amp power would be a lot higher than speaker power. The thing that generally melts speakers, more specifically Tweeters, is when the amp goes into distortion and produces square(ish) waves.

This is a bit like switching DC on and off into your speakers (and perhaps you like the smell of Blue Smoke, who am I to criticize?)

With a much higher powered amp you're actually less likely to get to those damaging square waves as even if there are peaks above the speaker rating they'll be a lot shorter and , theoretically, less likely to damage.

The other part of the equation is that the speaker 'Watts' are the same as the Amp 'Watts'....

I'll leave that to a wiser man than I though.....

Paligulus

Cheers Paul.

I wouldn't have thought about it like that, but it actually makes a lot of sense!!!

Paligulus

PaulBrewer wrote: »

The other part of the equation is that the speaker 'Watts' are the same as the Amp 'Watts'....

That's very cryptic!!!

PaulBrewer

Paligulus wrote: »

That's very cryptic!!!

Not really! There isn't an industry standard way to express 'Watts' ...
For example you see RMS watts and Peak Watts. Now RMS (Root Mean Square....no, I don't know either) watts are standard(ish).

So say your amp is 100 watts RMS it also could be 1000 Watts Peak i.e. that amp can produce 1000 watts for a 'peak' .
However even 'Peak' ain't what it seems either. How long for this peak? An hour? A second..... a Milisecond?

As far as I remember Crown amps peak spec refer to 100 hours peak. Anecdotaly I've heard that a popular cheaper brand begining with B's peak spec is for 10 miliseconds!

Gawd only knows what happens then, but I'd have a fire extinquisher nearby!

My point is 1 units 100 watts is much different to another's 100 watts!

That's not allowing for impedance issues either!

Stop , me heads meltin' !!

Frankiestylee

At a guess... is root mean square not the root of the average of the square of the highest and lowest bits of the ac, whereas the peak is just the highest point? Should be equal enough really... but it's been an age since I studied such shiz, I could be completely wrong. So um... don't blow anything up on my account.

Savman

Trust me, the watts figure in reality means absolutely zero. It's great to quote it to your mates but otherwise it gives no indication as to how a given speaker will perform. Personally, I'd only refer to watts to make sure I was properly matching amp power to speaker power and capability.

Generally as a rule of thumb, make sure your poweramp is sending 1.5 times the speakers' RMS rating. For more headroom, you can use an amp that'll send twice the speaker's RMS rating.

From the info you supplied it looks like you're perfectly powering your 300w speakers. One could argue that if you were to change to speakers rated @ 500w RMS you'd not yield a result you might consider "better" because in fact a 500w speaker would defo wanna be seeing 750-1000w of amp juice before it would come to life.

So looks like yer grand.

Paligulus

Cheers Lads. Thanks for putting me at ease on that one!!! As well as clearing up that prob. I actually learned something too!!! There was a bit more to this PA thing than I had previously though!!!!!!!!

And Savman, how did you know I spend the weekends waxing lyrical about the combined wattage of my gear to the lads?!!!!!!!!!!!

Savman

Many times I've heard fellas going on about their "5k rig" when it's probably running about half that, if even. Watts is such an arbitrary number for comparing PA spec and its very often used as spurious marketing blurb by various manufacturers to make their product sound better.

In reality, a 200w EV or Dynacord speaker could very well, and probably would, sound audibly "louder" than a Behringer equivelant rated at 600w. There are so many other factors to take into consideration, but they are all boring and wont impress any musos

Sgt Pepper

U can actually do more damage by being underpowered believe it or not. U should b fine with ur setup though. If it were me i'd get bass bins if i could afford it - they can take the pressure off the tops {and if ur a vocalist u'll find bins of great help cos u won't b competing as much for space in the mix. I always find having bins is also way safer than having speaker stands jutting out 2. Bins can give u a lot of peace of mind if people start dancing a few feet away from ya in smaller pubs/venues.

Paligulus

Sgt Pepper wrote: »

U can actually do more damage by being underpowered believe it or not. U should b fine with ur setup though. If it were me i'd get bass bins if i could afford it - they can take the pressure off the tops {and if ur a vocalist u'll find bins of great help cos u won't b competing as much for space in the mix. I always find having bins is also way safer than having speaker stands jutting out 2. Bins can give u a lot of peace of mind if people start dancing a few feet away from ya in smaller pubs/venues.

I was actually thinking of getting some bass bins initially before I found out that underpowering is worse.

Would Bass bins degrade the signal?
Also, and excuse my ignorance, but would they not make everything sound, well....very bassy?!!