Blown speaker?

[AcID ZeR0]

I think I might have ruined one of my Pioneer coaxials, every time I play music I get this horrible smell from the right hand side one.

I dont know how to describe it but it gets right up your nose almost toxic like,
The best way I could descibe it is if a moth hits a light and gets fried.
I've one of them uplighters in my room and they always seem to make there way onto the halogen bulb.

Anyway I took the grill off and it seems to be coming from the tweeter in the middle, for a start it has a slight hole in the size of a pin prick I only spotted it as the tweeter is silver.
Oh and there was a slight burn mark on it which rubbed off.

What you reckon, had it?
Normally I wouldn't care but these are half decent speakers.

 

[Dink]

sounds like it's dead.

are they running off an amp or a the hu?

either way sounds like you might have been giving them a clipped signal

 

[AcID ZeR0]

They are amped mate.
Sorry is there any guide you can point me through to tell me about clipping I always hear it mentioned.

 

[theduck]

clipping is quite easy to explain. Basically an amplifier produces a sine wave. This sine wave increases in size as you tur up the volume. Once the amplifier cant produce a big enough sine wave to produce the required output it 'clips' the signal. Basically chopping the top and bottom off the sine wave. This means it goes from looking like this \/\/\/\/\ to something like this \_/-\_/ this is what causes distortion, and this signal damages speakers, if you cause the amplifier to clip[ too much, it will actually output a DC signal, which cause speakers to go in quite an impressive way.

 

[AcID ZeR0]

Cheers mate, explained that great.

I do give my speakers some abuse but my amp should handle them all its running is two fronts rated at 40w RMS the amp is 400w max so I'm guessing 150w RMS - The speakers don't distort either.
My other amp is poweing my sub, and the amp which is doing the speakers was powerfull enough to run the sub so it shouldn't in theory struggle with two 13cm's.

Anyhow; one Pioneer later the system is fine, running a Pioneer on one side and a JVC on the other lol.

 

[theduck]

I know what you mean with what you are saying mate, but unfortunately it isnt always that simple. This kind of equipment and the physics behind it all is a lot more complex than you would imagine.

 

[Dink]

if you turn your hu up too loud it will produce a clipped signal (even on the pre-outs)

but it sounds like it might be just sheer power they gave into or you may have killed the cap for the tweeter thus giving it full range rather than just the highs

 

[theduck]

sheer power wouldnt cause burning, it would throw the drive unit out of the speaker, or suck it back into the speaker, depending on what point it failed.

The fact there was sign of burning, means that the voicecoil has recieved a distorted (clipped) signal. The reason he is getting the continuous smell of burning and poor sound quality is because the voice coil now has a short in it.

 

[muz]

duckeatsport best explanation of a clipped signal i ahve see on a forum

Power ratings dont mean that much, you can send a clipped signal using no power and it will damage voice coils. It is all about how you set up the gains and without using a scope you can never be sure of not clipping the signal

If it is just the tweeter element you might be able to get it fixed however you might be cheaper getting new ones

 

[theduck]

thank you muz! I worked in the hi-fi trade for about 4 years and picked up a lot of knowledge on these things in the process

 

[AcID ZeR0]

Got seperate tweeters now but still got one Pioneer and one JVC looking at the speaker again the top of the tweeter had a tiny dent in it.

 

[Dink]

sheer power wouldnt cause burning, it would throw the drive unit out of the speaker, or suck it back into the speaker, depending on what point it failed.

The fact there was sign of burning, means that the voicecoil has recieved a distorted (clipped) signal. The reason he is getting the continuous smell of burning and poor sound quality is because the voice coil now has a short in it.

there is only so much heat a voice coil can dissapate and with it being a tweeter it's not exactly designed to "move" is it??

 

[jamesy]

yep sounds like amplifier clipping to me, clipped signals contain excess high frequencies meaning they are potentially fatal to small drivers such as tweeters and small coaxials it basically kills speakers through distorsion the most common cause for speaker failure however if they are giving off a burning smell id say you've probably melted the bond that hold's the coil to the former also rendering it useless this is purely caused from overpowering its where the former cannot dissipate the heat generated the best former material seems to be aluminium also if you play your music loud for long periods the coil will eventually begin to reject dc current also causing vast amounts of heat to be generated now for a breath

 

[Dink]

yep sounds like amplifier clipping to me, clipped signals contain excess high frequencies meaning they are potentially fatal to small drivers such as tweeters and small coaxials it basically kills speakers through distorsion the most common cause for speaker failure however if they are giving off a burning smell id say you've probably melted the bond that hold's the coil to the former also rendering it useless this is purely caused from overpowering its where the former cannot dissipate the heat generated the best former material seems to be aluminium also if you play your music loud for long periods the coil will eventually begin to reject dc current also causing vast amounts of heat to be generated now for a breath

lol clipping is where the sinusoidal wave becomes a square wave and a square wave at the same frequency as a sine wave will contain nearly twice the power.

rejecting dc current:S

 

[jamesy]

LOL ok trev

(rejecting dc current when the coil reaches a certain temp)

 

[tommyboy]

something smells dodgy to me, not just your speaker lol. hope this doesnt happen to me pio's

 

[Dink]

so rejecting dc current from an ac source.

that's a good un

 

[theduck]

dink if a tweeter was designed to NOT move, it wouldnt work now would it lol. I understand your point, i just disagree with you.

 

[Dink]

the "" were put in cos i know it moves but not like a woofer would

as it pretty much just vibrates

 

[The Bear]

Make sure you have your amp gain and your HU volume set up properly with any new speakers. This is the best way I have read:

1. Turn your amplifier's input level controls all the way down.

2. Put in a tape or CD or tune in a radio station. Turn up your receiver's volume control. You'll begin to hear music at faint levels. (Audiophiles and sound competitors may want to use a dedicated test disc.

3. When you start hearing distortion, lower your receiver's volume control until the distortion disappears. At this point, you have as much signal as possible passing from your receiver into your amp. (This gives you maximum signal-to-noise ratio, so you'll enjoy clean sound and your system will be less prone to engine noise problems).

4. Now begin adjusting your amp's input gain. Turn the input level controls up until the system is as loud as you can stand it or until you begin hearing distortion — whichever comes first. If you hear distortion, decrease the gain settings slightly.

By following this procedure, you'll optimize your amp's performance at the receiver's maximum volume level, so you can crank your system almost all the way up without amplifying any distortion, or damaging your speakers. Keep in mind that this adjustment does not affect the power output of the amp — you're simply setting the amount of input signal needed for optimum sound quality from your system.

From - Crutchfield Advisor - Very good guides and FAQ's.

 

[Dink]

Make sure you have your amp gain and your HU volume set up properly with any new speakers. This is the best way I have read:

1. Turn your amplifier's input level controls all the way down.

2. Put in a tape or CD or tune in a radio station. Turn up your receiver's volume control. You'll begin to hear music at faint levels. (Audiophiles and sound competitors may want to use a dedicated test disc.

3. When you start hearing distortion, lower your receiver's volume control until the distortion disappears. At this point, you have as much signal as possible passing from your receiver into your amp. (This gives you maximum signal-to-noise ratio, so you'll enjoy clean sound and your system will be less prone to engine noise problems).

4. Now begin adjusting your amp's input gain. Turn the input level controls up until the system is as loud as you can stand it or until you begin hearing distortion — whichever comes first. If you hear distortion, decrease the gain settings slightly.

By following this procedure, you'll optimize your amp's performance at the receiver's maximum volume level, so you can crank your system almost all the way up without amplifying any distortion, or damaging your speakers. Keep in mind that this adjustment does not affect the power output of the amp — you're simply setting the amount of input signal needed for optimum sound quality from your system.

From - Crutchfield Advisor - Very good articles and FAQ's.

or you could use some test tones and a scope

 

[quez]

same thing happened to my components once which were rated @ 180w rms but only getting a max of 150w rms maybe less, the problem is more likely to be your amp then your speakers altho the speaker is blown, jus be more careful with the amp in future, I smashed mine up since it was a £600 set of components it blew!

 

[The Bear]

Incidentally, you can download a whole range of test tones for gain level setting and to indentify clipping from here:

http://www.resnet.trinity.edu/areynol1/hosting/test_tones.zip

Whack them on a CD and bingo. Much easier to hear distortion/clipping than with a music track.