what inputs to poweramps have then? I always thought they had XLR inputs to run from the mixer's XLR main outs and speakon outputs.

[QUOTE=airborne50caliber]what inputs to poweramps have then? I always thought they had XLR inputs to run from the mixer's XLR main outs and speakon outputs.[/QUOTE]

oh, d'amn, thats a point. i guess higher end poweramps have balanced inputs.

Ihave a queastion do you need a pa. when we play shows the house have the mixer and speakers is this the same alaroun pretty much. durin practice we just run it through a guitar amp and it works fine

it will damage the guitar amp in the long term. Enough said, there's too many thread os this. Certainly dont play shows through one.

I have a question regarding the main volume controls on power amps.

Are you sopposed to run these full go and let your mixer or other preamps control the volume?

Also, say you had them up only 1/4 of the way would this mean that you are taking away the amps headroom and allowing it to clip at lower volumes, or is it merely stopping the preamp from boosting the level louder?

old speakers
 

Hey, I have a couple of really old JVC speakers hooked up to a big stereo system, and I was wondering if there's any way I can use them as studio monitors or something. My problem is that they use standard speaker wiring, and I don't see any way that I could plug it into my mixer. My mixer is a brand new Samson MDR 6, although I'm thinking of returning it and getting a better mixer because this one creates a buzzing noise when I record. Thanks for the help.

do you mean those bare orange speaker wires?

Moaner: The inputs of poweramps are for a line level signal. You can run a mic into them (if needs be) but it'll be quite quiet.
Ideally you'll want a preamp for the mic anyway.

Manimal:
Couple of reasons.

It is good practise to keep the volume on the poweramp pretty much maxed out all the time. And control the loudness via the output level on the mixer.
In bigger setups, the poweramps are right down the stage next to the main speakers. Right? The mixer is up the back of the room. You'll be at the mixer.
This way, you can control the levels where you are instead of having to run down to where the poweramps are and turn them up there.

Secondly. With the clipping indicators on the mixer, you'll have a good idea of where the poweramp will be clipping too.
You could be as loud as you need while only having the main level sliders on the mixer up half way. Instead of having the poweramp up only half way with the main level sliders on the mixer up full (and starting to clip).

nullifiedblaze:
I wouldn't reccomend it. Studio monitor speakers are designed to sound as neutral as possible.
So when you mix your music and it sounds alright on the monitors, then it should also sound good in any stereo you play it on.
If you mix some music and get it sounding good on your computer speakers, then it might sound like crap on your car stereo speakers. and etc.
Real studio monitors are reccomended.

Clear speaker wires like these:

[url]http://www.bestbuy.com/site/olspage.jsp?type=product&id=1051384447132[/url]

Well since I can't use them as monitors, can I still use them as just speakers? I just want to know if it's possible to hook them up to my mixer.

not without some very strange kind of adapter.

What is the point of stereo operation on power amps? Its not like you can utilize a stereo image at a live gig. Not everyone would be able to hear everything. The only benefit I can think of is higher impedence. But that means less power as well.

Wouldnt it be better to just run 2 8 ohm speakers in parrellel to get a 4 ohm load and more power?

[QUOTE=Manimal]What is the point of stereo operation on power amps? Its not like you can utilize a stereo image at a live gig. Not everyone would be able to hear everything. The only benefit I can think of is higher impedence. But that means less power as well.

Wouldnt it be better to just run 2 8 ohm speakers in parrellel to get a 4 ohm load and more power?[/QUOTE]
Yeah. You can utlise stereo dynamics at gigs. You can pan two guitars into differnt fields.
Also, having the toms panned across the stereo image in a nice effect to have, as the drummer does a fill it can sweep from the left to right fields.
Plus, you can really make use of stereo FX, such as Chorus, Pans, and Ping-pong Delays.

But, this all depends on the size of the gig. If you arn't playign huge 1000+ people shows. Then who cares about stereo dynamics right?

And, in larger setups like these. Power is of no concern. Trying to milk out extra power from differnt speaker configs will be unecessary, as the poweramps use would be more than adequately powered for the venue as it is.

But, often, subwoofer drivers are just mono. Often just ran off a poweramp that has been bridged. As these low frequencies are omnidirectional there is no point in having both a left and right field.

Are most gigs ran in stereo or mono?

stereo.

alright everyone is probly gonna flame me, but i just wanted to make sure of something. i play guitar, use a 120w rogue amp(****ty, yes i know, i needed something loud enough for cheap real quick), bassist uses a 60w for now, gettina 80/100w pretty soon, drummer doesnt mic. now, our singer is getting a PA system, its 80w, and has 2 8" speakers. Right now hes using a little 50w combo, and thats not loud enough at all. My question is, the pa system with 80w should be loud enough right? oh and if it matters, its just gonna be him and then the bassist as a backup singer going through it, no micing the guitar and bass amps or anything

[QUOTE=devildriver421]alright everyone is probly gonna flame me, but i just wanted to make sure of something. i play guitar, use a 120w rogue amp(****ty, yes i know, i needed something loud enough for cheap real quick), bassist uses a 60w for now, gettina 80/100w pretty soon, drummer doesnt mic. now, our singer is getting a PA system, its 80w, and has 2 8" speakers. Right now hes using a little 50w combo, and thats not loud enough at all. My question is, the pa system with 80w should be loud enough right? oh and if it matters, its just gonna be him and then the bassist as a backup singer going through it, no micing the guitar and bass amps or anything[/QUOTE]

should be fine. just set the vocal level first and the other things aorund it.

[QUOTE=drum_player4life1]Ok my PA suddenly just like ****ed up. I can get sound through it, but the compression light is like on if i turn it up the slightest. And the sound is terrible its all staticy and unclear. It's terrbile, and it isn't the speakers. So anyone? Have any idea what's wrong and what needs to be done to fix it?[/QUOTE]

compression light? Maybe adjust the threshold to get rid of that lil' bit of turd.

Could anyone possibly offer a technical explanation as to why running a vocal mic into a guitar amp would damage it? I've been a professional sound engineer for 8 years and I have to say I think the theory it will damage the pre-amp is complete nonsense!

The pre-amp in a guitar amplifier is no different to that in a mixing desk or hi fi amplifier, it just has a frequency response and EQ optimised for guitar.

As for the higher bandwidth of the human voice being the cause of pre-amp damage, I suggest anyone who believes this connects their guitar to a spectrum analyser. You'll be surprised just how wide the bandwidth of ANY instrument is. The real top end of the Human voice (S's and T's) tend to be in the 8-12kHz range. Even my G&L L2500 bass can register a lot of 8kHz on an analyser.

I've honestly never, in a total of 10 years mixing, heard a mic can damage a guitar pre-amp, and I can see no technical reason why it should.

I'll wait to be convinced otherwise:)

Paul

Hey there guys.
Well i finally got my PA setup, and id just like to write in to others can learn from my experience.

Firstly, if i havent mentioned before...me and 2 other guys jam everyweek in a music classroom, about 12-15m x 12-15 metres... we dont gig, and dont intend to yet anyways..but just jam for fun. We have a drummer on one end of the room, a lead guitarist in the middle using his own amp... not too loud..but loud enough for rockin..... and im on the other side playing semi-accoustic guitar (do rythm work), and singing.

So being the singer, and lead guitarist, i not long ago decided to get a PA system for myself to use with our band. I did a fair bit of research, as i was very new to this all... and found that i needed (as i wanted to amp my vocals and guitar) a: 1) powered mixer and 2) matching Loud Speakers, plus 3) quality loud speaker cables (speakon which matched both amp and speaker ends).

So this is what I purchased:
1. Behringer EUROPOWER PMH880S
Ultra-Compact 2 x 400-Watt 10-Channel Powered Mixer [url]http://www.behringer.com/PMH880S/index.cfm?lang=ENG[/url]
$560 AUST

Main thing was that it gave out 2 x 200Watts @ 8ohms.


2. 2 x 15" PA Accusound LoudSpeakers
[url]http://www.accusound.com.au/PA_Series.html[/url]
$360 AUST

Main thing is that they are each at 200w RMS @ 8ohms and 96 dB@1watt. So I figured it was a good match.


3. 2 x 10meter Speakon to speakon quality loud speaker cables (NL2FC neutrik)

So…
We use it… I have my mic in channel 1, and my semi-accoustic guitar in channel 2… ive basically experimented alot with the system, and Aes820 I have to thank you again for helping me with all the silly questions ive asked hehehe..

Anyways… HERE IS THE PROBLEM.
To explain this is the Clip lights setup. There are 6 Lights: Bottom light -10, next is -5, middle light is 0, next one up is +3, and highest light is LIM.. some kind of limiter.. and from what ive read, its not good to get it on this light.. its only a safety mechanism.

Anyways the problem is that i thought this system would be loud enough.. considering we are by ourselves, no crowd.. and just want a nice sound and for vocals to be heard nice loud and clear. Believe me im not an overly loud person.. ie. My ears a good, and I hate playing things too loud.. ie. We never get deafining loud with the electric guitars or drums.

So.. I put it a nice level, so that vocals can be heard well, and I can actually hear myself sing and so can the other members. Unfortunately to do this, the mains have to be turned quite high.. atleast ¾.
When I sing normally, the lights reach about -5, ie 2 lights.. but then when I sing harder its constantantly around the +3 mark… which scares the crap outta me, since I could go even harder, and im holding back. So I usually have to pull away from the mic (even though im never that close to it in the first place). Once I screamed pretty hard and the LIM light was reached momentarily.. which really pissed me off… means I have to hold back on a system that isn’t producing a good level for me… and again.. our drummer is just a normal drum, ie doesn’t hit the drums hard.. and the electric guitars are loud..but not deafining loud…

Even when playing just acoustic (no electric guitar), when I sing normally its great, but when I push it vocally, and even pull away from the mic, the lights approach the +3 and LIM…


The system (which pretty much runs at 200rms at 8ohms) does preduce very very clear sound which is great.. but we are already reaching its limits.. and we aren’t even playing live at a bigger venue.

Basically what I want, is something that preduces the level (max loudness im currently preducing) but at about halfway of the PAs (amp/speakers) power… that is so there is no fear whatsoever of reaching the volume we require without clipping… and there is always more power/volume if required…

So its kinda sad to say.. but im pretty fussy bout all this, and am thinking the best thing to do is sell what I have… ie. Poweramp and speakers, which weve only used about 4 times… and get something better.
This doesn’t really annoy me or anything, because we haven’t broken anything, and yeah I may lose a fair bit of money having to sell these items cheaper..but its all valuable experience I think 
I just wanted to let u guys know about my experience and hope people can either learn or make some inputs etc. Just felt like sharing the story…

Well its another long post haha so ill finish it off.
Is it possible to get a system similar size to the one I have (physically speaking), and have twice the power??? And how much will I have to pay.. I have the cables, so all I need is a Powered Mixer and 2 Loud Speakers. Ofcourse itll be more expensive, but does anyone have any advice??? Someone initially told me, and that was a guy who gigs regularly at pubs and clubs, that all I need is 150w RMS speakers… I don’t know that I can believe that considering 200w rms isn’t good enough for us in a classroom… btw.. one thing I haven’t mentioned is that the speakers are at 96 dB@1watt/metre.. im figuring that may be something I didn’t take into consideration… anyone know ??

Back to research.. and btw… im not dissing this amp.. its bloody great.. great sound..truely amazing.. just the level isn’t what I expected. Or it’s the speakers ahahah

Take care guys,
Steve ;)

I'm no PA expert but I like to contribute so here goes:

I highly doubt that system was rated at RMS. 200 watts RMS should have been plenty loud. You say it gives you 200 watts x 2 at 8 ohms and its not enough. Perhaps you could try using a 4 ohm load (The description says 2 x 400 watts so I asume thats a 4 ohm load they are talking about) and get more power out of it. Or you could brigde it and run your speakers in parrelel.

Honestly I think its your speakers that are keeping you from getting your desired volume.

its unlikely you'd have volume problems with a 200w system in a classroom. As yo your clipping problem- some kind of limiter (like the one vuilt inoto the behringer MIC200) might help.

[QUOTE=PMN]Could anyone possibly offer a technical explanation as to why running a vocal mic into a guitar amp would damage it?
[/QUOTE]
In my understanding. Because of the difference in impedence between the mic and that of an average guitar pickups. The mic will cause the input stage of the guitar amp to overdrive much easier.
Having the input stages constantly overdriven will wear eventually them out.
In much the same way as running something like an overdrive pedal with very high settings into a little amp will, after time, wear it out.

Also, bare in mind. That those who run setups like this often run these amps with their volume maxed out also. Which does little to prevent long term damage.

From my own experience, I have heard little practise amps that have been abused like this. And they do sound as if they are completely worn out. As if they are always distorted. Full of sand.

[QUOTE=aussiegnr]So.. I put it a nice level, so that vocals can be heard well, and I can actually hear myself sing and so can the other members. Unfortunately to do this, the mains have to be turned quite high.. atleast ¾.
When I sing normally, the lights reach about -5, ie 2 lights.. but then when I sing harder its constantantly around the +3 mark… which scares the crap outta me, since I could go even harder, and im holding back. So I usually have to pull away from the mic (even though im never that close to it in the first place). Once I screamed pretty hard and the LIM light was reached momentarily.. which really pissed me off… means I have to hold back on a system that isn’t producing a good level for me… and again.. our drummer is just a normal drum, ie doesn’t hit the drums hard.. and the electric guitars are loud..but not deafining loud…

Even when playing just acoustic (no electric guitar), when I sing normally its great, but when I push it vocally, and even pull away from the mic, the lights approach the +3 and LIM…

The system (which pretty much runs at 200rms at 8ohms) does preduce very very clear sound which is great.. but we are already reaching its limits.. and we aren’t even playing live at a bigger venue. [/QUOTE]
Gidday Steve.
Um. I'd like to see how you've got this all setup. Because I cannot see how this setup could not be as loud as you'll ever need.

I've got a couple of 300 watt powered speakers and these are seriously loud. I've rarely even come close to limiting these things, even while gigging.

Give me a call, one evening this week. Anytime after 5pm.
0411 295 116

Hey there Chris.. yeah im puzzled as well...
Everyone ive talked to, prior to testing this system out, including the local music shop and musical internet buddies, say that what i have will be awesome...
Something is a miss though...
Speakers say 200w rms @ 8 ohms (400w peak), and amp gives out 2 x 200w @ 8 ohms.. so it definately would be capable of reaching around that figure.. im guessing thatd be the max output????

But again, some guy told me recently that 150w speakers (im pretty sure he meant at 8ohms since most speakers are at 8ohms.. well ones ive seen on ebay) would more than enough for a pub gig.

Dont get me wrong.. i play these speakers pretty loud... im about 4 or so metres away from the speakers when i sing and play my accoustic guitar and can hear them well... but that this ideal level (which i know isnt deafining loud) the levels on the amp reach the top if sing hard...
im thinking maybe the speakers are dodgy... or something i dont know... or can it be the mic??? i have a shure but its a pg variety.. not the best.. but still ok..worth bout $100 australian... nah it cant be the mic

ok, ill give u a call chris.. thanks for that. Id really appreciate some help. Im almost 100% that i have this all set up correctly.. i mean itd be kinda hard to not set it up properly heheh but yeah.. im open to any help..cause as i said..somethings just not right. As i was expecting, getting to the ideal volume level of vocals over drums and electric guitar, with only about Half of the max amp output. Anyways.. ill give u a call soon, and ill let u guys on this forum know how it goes.... im sure people will learn something from this hahah who knows .. ill keep ya all posted... i may not have to sell the system after all. And thanks for all the comments guys, much appreciated ;)
cheers,
steve

[QUOTE=Manimal]I'm no PA expert but I like to contribute so here goes:

I highly doubt that system was rated at RMS. 200 watts RMS should have been plenty loud. You say it gives you 200 watts x 2 at 8 ohms and its not enough. Perhaps you could try using a 4 ohm load (The description says 2 x 400 watts so I asume thats a 4 ohm load they are talking about) and get more power out of it. Or you could brigde it and run your speakers in parrelel.

Honestly I think its your speakers that are keeping you from getting your desired volume.[/QUOTE]

Thanks for your input dude.. much appreciated.
Well i hope this helps..The amp i got says 2 x 400 @ 4 ohms, and 2 x 200w @ 8 ohms... this figure is whats important i think, since the speakers i got are at 8ohm rating. These are the speakers i got:
[url]http://www.accusound.com.au/PA_Series.html[/url]
SPECIFICATIONS
System 2 Way Trapezoidal
Power Rating 50-200 Watts RMS
(400 watts Peak)
Frequency Response 25-20 000Hz
SPL 96 dB@1watt/1metre
Impedance 8 ohms Nominal
Components 1 x 380mm (15”) Long-throw LF Driver
1 x 25mm (1”) HF Compression Horn
Colour Black Carpet Finish
with ABS Protective Corners & Carry Handles
Weight 18.25 Kgs each
Dimensions 585mm(H) x 448mm(W) x 430mm(D)

Before i bought them, i asked the RMS, he said comfortably at 200w rms..
even the box says the power handling (which i guess is similar to rms) is at 200w rms.. and peak is 400w.

So unless there is some false advertising i cant see how ive stuffed the matching of speakers to amp hmm its interesting. BTW..does the db have much to do with it??.. mine are at 96db.

My speaker cables are 10m long.. that couldnt be the reason right???
well talk soon,
steve

I am considering buying a Peavey PV-115 15" cab to go along with my PA system I'm scrapping together. I think I understand most of this stuff at this point, but I'd like to clear up a few hazy parts of my understanding.

The speakers are rated at 300W program, 600W peak @ 8ohms. So if I ran them in parrallel, I'd need a power amp that can drive 2x600 @4ohms, correct? Or would I only need 2x300? Some guides on the internet aren't as helpful as they are confusing...

[QUOTE=painball]The speakers are rated at 300W program, 600W peak @ 8ohms. So if I ran them in parrallel, I'd need a power amp that can drive 2x600 @4ohms, correct? Or would I only need 2x300? Some guides on the internet aren't as helpful as they are confusing...[/QUOTE]
If you'll just be running two speakers off the one poweramp. You'll need a poweramp rated at near enough to 2x300 watts while at 8 ohms. (although many poweramps are rated at 4 ohms, so in which case you'll need a 2x600 watt while at 4 ohm poweramp).

Dont worry about Series or Parrallel connections unless you are combining more than one speaker off one of the poweramps outputs.

Why exactly would you double the wattage when you halve the resistance? Wouldn't that overdrive the amp and speakers?

whats the diffference ebtween resistance and impedance, or is impedance just the american word for it?

[QUOTE=airborne50caliber]whats the diffference ebtween resistance and impedance, or is impedance just the american word for it?[/QUOTE]

hmmm... They are essentially the same thing, you'd just use them in different contexts i think.