Gonna blow my speakers!!

[Tiefer]

i use a numark M1 usb mixer and laptop to dj house parties. the speakers i use are just a sony system, 2 speakers + sub. the sound system does enough for the small rooms i play in. i notice after about a half hour this burning plastic smell comes from the speakers. i realized today that mid and highs were +6 on the sound system so i reset them to normal. Is this most likely the issue or was it because the music was too loud, or gain too high on the external mixer etc? any ideas how to fix this so i dont have to buy a new system?

thanks

[Jester]

Best to set the EQ on the sound system to as flat a setting as possible, and work out a good balance between the input level from the mixer to the output from your stereo. I think as a general rule you want the master volume on the mixer to be low and let the stereo do most of the work, Depending on the wattage of course.

[pier]

Yeah the coils in the speakers get hot depending on the amount of voltage they receive. So more volume more heat.

[Jester]

Blown speakers are a sure sign of a good party tho

[Tiefer]

Blown speakers are a sure sign of a good party tho

hahaha! im doing a party this saturday so we'll see how it goes


well i thought the volume on the sound system should be low and the mixer high,uh oh, i guess i will change that this time

thanks a lot for the help!

[pier]

well i thought the volume on the sound system should be low and the mixer high,uh oh, i guess i will change that this time

Yeah that is the theory.

Why?

Because when you send your signal to the amps of the sound system the noise of the mixer gets raised up. If your signal in the mixer is low your signal to noise ratio is low, and you need to up the gain in the amp. So more noise will be amplified in the amps.

Also for the health of the sound system it's alway better if it doesn't work at their max levels.

Of course sometimes the party is the party and you need to crank it up

If you do that it's better to do it progressively. Start low and end up high. People's ears get accustomed to a certain level. If you start high then you'll want to raise it and you'll have to crank the EQ or the gain of your mixer and feed distorton into the sound system. Not only that is terrible to the system, but also to everyone's ears.

[Tiefer]

so to clarify:
mixer volume high, stereo system volume lower?

[pier]

Yes, mixer as high as you can without distortion.

If it's an analog mixer you're allowed a little bit of red lights on the highest peaks. Only a little bit. If it's digital you're allowed zero distortion.

In analog gear a bit of distortion gives the sound some nice punch. Plus you get a higher signal to noise ratio.

In digital, distortion or clipping means destroying the signal. When your signal reaches the top it goes flat.

[Fatlimey]

Why speakers blow:

Every speaker driver has a frequency range they are good at reproducing. When you feed it a signal outside of that range it still tries to reproduce that signal but fails because the signal is either too fast or too slow for it to make the necessary movement. You just pumped energy into the driver and got no movement out of it, so all it can do is heat up.

The most extreme example of this is a "DC offset" where the driver is being fed a constant signal as well as a varying sound, so the driver is pegged fully open before it has to vibrate, essentially banging itself against the end stops until something breaks.

Combating DC offset and low frequencies is the job of a "crossover" inside the speaker, a circuit you usually see glued to the inside of the cabinet. Large capacitors are there to remove the DC offset, and the coils are there to remove the low frequencies. It's also possible to buy "crossover" boxes that do this job digitally on the signal before you feed it to the amplifier - more control and greater possibility of killing your speakers if you don't know what you're doing.

It's a little more complicated than that as the amplifier is also part of this "elastic" system and can force a driver to follow a signal just by pumping more power into the driver, and the driver in turn pumps small amounts of power back to the amp as it comes to rest.

So, rules to follow:

1. Your amp must be way overpowered for your drivers. If your speakers say 500watt, think about pairing it with a 1kw amp. The extra power will give you a better sound.
2. Try to filter out signals to the speakers that it can't reproduce. If your speakers have a low end at 100Hz, don't send it 30Hz bass. Filter it at the desk or maybe your amp has a highpass filter and a limiter (and by highpass, we really mean pretty damn low).
3. Best is to "bi-amp" your rig, to have two amplifiers, one specifically for the bass speakers and one for the mid-top. You split the input before the amps using a crossover into a low and high signal and feed each into into a different amplifier which feeds different speakers.

These details, plus the fact that 1KWatt subbass speaker drivers are about $200-$500 each, explains why "the guy on sound" is usually pretty touchy about you fucking with his gear!

[pier]

[*]Your amp must be way overpowered for your drivers. If your speakers say 500watt, think about pairing it with a 1kw amp. The extra power will give you a better sound.

Why is that?

I always heard it was the contrary, because that way it's more difficult to blow the speakers.

Maybe you mean using a 1K amp at low volume so you never overheat the amp?