Damaging Monitors?

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Tangled Cords

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I recently bought a pair of Event PS8 monitors wich are amplified. I used 1/4" guitar cords to hook them (No No?) and after a few hours I noticed the woofer on the right monitor has crackling and had no bass response. I was listening to bass heavy music but not very loud. Anyways dropped it off to have a new woofer installed, been two months and it's still there. A few weeks later I'm Playing my guitar line in via a POD with sonar getting a good chunky tone and the the other one starts doing the same thing. What is the deal with monitors? are they extremely sensitive? Again I didn't really have the volume up very far. I'm not sure if I should be using 1/4" speaker cable instead or not.
 
I don't think it's the cable. Any 2 conductor cable should work. If the amplifier driving the speakers has a balanced out, you could also use a three conductor cable (TRS - balanced) but that's another topic.

On the surface, it doesn't sound like you did anything wrong. Here's a few things to check:

1) What are you driving the monitors with? It it's a line level output from you mixer or DAW you should be okay. Make sure you're not overdriving the monitors. Turn down the amplifier output, turn up the volume control on the monitor.

2) Have you had problems with feedback loops in the past? You know, you turn up the monitors and forget the microphones are still on ... SCREEEEECHHHH! Ouch. I burnt up a tweeter that way; don't know if it could hurt a woofer.

3) Are the monitors used? Maybe they were slightly damaged before you got them.
 
Turning down the amplifier is actually a really fast way to blow monitors. Overpowering is much safer on drivers than underpowering and as a result overloading the amplifier with signal.
 
xstatic said:
Turning down the amplifier is actually a really fast way to blow monitors. Overpowering is much safer on drivers than underpowering and as a result overloading the amplifier with signal.
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I use my mixer mains to feed the monitors and routinely turn the mixer output all the way down when using headphones to track. Are you suggesting this is bad practice?

I think I'm missing something.
 
What soundcard do you have?

I had a similar problem with crackling (although I didn't notice any problem with the bass) when I got my IMF's.

I even posted the problem on a hi-fi forum and the consensus was that the speakers were knackered.

It turns out the outputs on my soundcard were set at +4dbu causing the speakers to distort.

So I set them back to 0dbu and it cleared up the problem.
 
Phyl said:
I use my mixer mains to feed the monitors and routinely turn the mixer output all the way down when using headphones to track. Are you suggesting this is bad practice?

I think I'm missing something.
Click to expand...

That is certainly not bad practice, and in no way could that damage your speakers. I was referring to turning down an amplifier, meaning a power amp, and not a summing amplifier. The only time I ever trun down a power amplifier is when leaving it at full does not offer enough control at the console end (or whatever volume pot is being used). If the slightest move on your master faders results in way too much change in volume, then I go and turn down the amplifier.
 
Wow does that apply to live-size stuff too? So if I have a big power amp set to '5' it's a bad thing? :confused:
 
I would say it definately applies to live stuff. IN fact, probably even more so to live stuff. Every once and a while there are reasons to not leave amps set at full, but in about 97 out of 100 systems I work with and retune for people, I almost always need to crank the amps wide open to really let the system work. Unless of course the amps are being used as some sort of ghetto crossover, or for overall zoning volumes. I use a nice big convection cooled QSC on my Dynaudio BM15's. For almost 8 years now I have used the same amp. Even with little Alesis Monitor 1's. I have never blown a driver because that amp was wide open.
 
That's really interesting. I've never heard anyone say anything like this before, or see it practised. Where's your info from? I'm not doubting ... just would like to get my head around what you're saying a little more.
 
xstatic said:
Overpowering is much safer on drivers than underpowering and as a result overloading the amplifier with signal.
Click to expand...

Well, having an amp that can deliver more clean power than your speakers can handle can be safer, if you pay attention.

Clipping the amp can result in very high power levels to the tweeters, so you are essentially right. :)
 
noisedude said:
That's really interesting. I've never heard anyone say anything like this before, or see it practised. Where's your info from? I'm not doubting ... just would like to get my head around what you're saying a little more.
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Speakers blow for two reasons, pretty much: They get too much power and heat up too much, or they move too far. The danger of an amp rated for less than your speakers can handle, oddly enough, is that you will feed them too much power.

As you clip the amp, the average power level output rises, like using a compressor. The peaks get rounded off, the low level signals come up.
So the speakers have to take more juice, on average. Average power handling is usually a lot less than peak.
Clip hard enough, and average power output of your amp approaches peak output.

As the signal clips more and more, the lows clip, but the highs still have headroom. So as you drive the amp harder, the highs get way more power than they should. A full-range speaker has a ratio of like 90/10 for a ratio of how much power the lows/highs can take. Clipping an amp hard can raise the power level of the high freqs dramatically, putting your tweets at risk as it compresses your signal.

Amps also can put out more juice than they are rated for. Amps are rated for power at a certain % distortion. They can put out more, but with more distortion. Many amps can put out peaks up to twice their rated power.

Put the higher average output together with lots more power to the highs, plus the fact that your amp puts out more than you think, and it's easy to blow speakers when you think you are safe with a small amp.

However, you will never blow a 1000W speaker with a 1 watt amp, no matter how hard you clip it,
 
My experience comes from being a full time engineer and system tech. I ran a pro audio company, privately contract, worked with over 1000 bands and on probably a couple of hundred different systems. There are always "exceptions to the rule" of course and reasons why someone may not run their system that way, but if proper gain staging and equipment purchase and set up is practiced, then amplifiers will usually end up wide open.

Think of it as putting a governor on your car at 40 miles an hour. Every time you try and go 60 you are just adding extra stress to the engine. Take the governor off and you can run nice and smooth at 60. But you still have to remember that your car does have a limit. If you choose to constantly press 120 when your car is not designed to than you will still have a problem. So either way there is a problem, but which problem would you rather live with?
 
Yeah - but if I only need half the power of my amp, should I use my amp at full power (possibly well over the rated handling of my cabs) and have the masters on the desk really low? That still doesn't quite make sense to me.
 
as a general rule of thumb, people in the pro audio industry tend to triple power their setups. This means if you want to power a 400 watt RMS speaker, you hit it with an amp capable of 1200 watts. A little bit of crossover tuning should put your system in a comfortable operating range.
 
noisedude said:
Yeah - but if I only need half the power of my amp, should I use my amp at full power (possibly well over the rated handling of my cabs) and have the masters on the desk really low? That still doesn't quite make sense to me.
Click to expand...

Like xstatic said, proper operation is about understanding your gear.

It's totally fine to turn your amp down to get appropriate volume to keep your console in a decent operating range.

The problem doesn't come from turning an amp down. The problem comes from using an amp that can't provide enough clean power to get you the volume you need.

Amp controls should be called "sensitivity" not volume.
The volume control determines how much signal at the input is needed to drive the amp to full power.
With the volume knob all the way "up", the amp might need 1 volt to get it to full power. With it halfway down, it might need 5 volts.
It's just like the trim knob on a mixer. Turn up the trim, the mic pre is more sensitive.

So a big amp turned down isn't a problem. It just takes more juice to get it to put out full power.

The problem is when an amp is run wide open, and still doesn't give you enough power. You push the amp into clipping pretty quickly, as the amp takes very little console output to drive it to full power and beyond, and get the problems that can result from that. (Signal compression, raised average output, etc., as well as the horrid sound of clipping).

Like xstatic also said, it's a more common problem in live work, as people usually run their amps wide open and their speakers as loud as possible. :D The system is already at the edge, in many cases.
 
Actually, turning the puput of an amp down is adding more of a probability that you will overload the amplifier in order to get volume. Speakers will handle amps a lot better than most people think. What they won't handle well is an amp that is clipping.
 
That's where knowledge comes in. If you dial your amp back, you just need to know how much extra signal you can put in without clipping, and don't go past that. If you hit that point and need more volume, turn up your amp.

If your amp is set at 0db, a 0db signal gets full power from the amp.
If your amp is set at -6db, +6db signal is needed to get full power from the amp.

Thing is, a lot of amps aren't calibrated this way. :mad: They go from 0-10, or some stupid crap, and you have no way to tell what you are really doing to the sensitivity.

And many amps these days have built-in limiting, which sounds better all the time. So sometimes you don't even realize you are clipping, because it doesn't sound as bad as it used to.
 
So I wonder if the volume knob on the back of my active monitors are actually controlling the the amp power (in which case I should turn them all the way up), or just an attenuation knob like a mixer or something (in which case I would prefer to keep them around the middle so as not to push them too hard)?

What do you guys do with the volume knob on your active monitors?
 
wow this is new to me.. I got a pair of KRK RP8's and i dont really wanna hurt them at all. They are connected to my Yamaha MG 4/12 mixer but will be soon directley connected to my Audiophile 2496. I have them set to 0db already. So i should be good right there right? .. :( yes i know im a n00b.
 
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