can a square shaped waveform do damage ?

[peterpiper]

the reason I ask i did a am embarrisingly silly mistake, after setting up my system after having the the new carpet fitting i accidently connected the cd player to the PHONO input

, yes I know,

confused as to why there was no sound I turned the tape loop knob , the speaker a/ b switching and the input selector, then oh s**t horrible garbled sound that sounded like a cliped signal came through the tweeters, luckily the volume was not that high, but now worried that I have done any as yet unkown damage to the tweeters?,

they sound normal ,but would a clipped square wave being amplified do damage ? , even though the amp itself was not clipping because the volume pot was only at 9 oclock position, it was just a signal that was clipped passing through

 

[Anderson]

Hi

Firstly, your CD player outputs analogue same as a record player.

You probably overloaded the phono input which is much more sensitive than any of the other inputs on your amp because a turntable puts out a much quieter signal (I'm so technical). What you heard was probably severe clipping, it's bad but provided you jumped to turn it down/off and you can't hear any lasting damage then you should be fine.

if someone more knowledgeable can explain better or correct me Id really appreciate it

 

[peterpiper]

Hi

Firstly, your CD player outputs analogue same as a record player.

You probably overloaded the phono input which is much more sensitive than any of the other inputs on your amp because a turntable puts out a much quieter signal (I'm so technical). What you heard was probably severe clipping, it's bad but provided you jumped to turn it down/off and you can't hear any lasting damage then you should be fine.

if someone more knowledgeable can explain better or correct me Id really appreciate it

yeah, the volume was not high thank god but the fact that it was a clipped signal had me worriying i may have done somthing , but all seems fine now, but it is interesting if a 'representation' of a clipped waveform will potentialy to damage, as that what it was really , it was basically a square wave being fed into the preamp, then main amp and coming through the speakers. but the main amp was not clipping , just the signal being fed through if you know what i am getting at , surley this must be a common mistake by newbies, but cretins like me should know better, but the room was dark *blush*

 

[Anderson]

Hi

Firstly, your CD player outputs analogue same as a record player.

You probably overloaded the phono input which is much more sensitive than any of the other inputs on your amp because a turntable puts out a much quieter signal (I'm so technical). What you heard was probably severe clipping, it's bad but provided you jumped to turn it down/off and you can't hear any lasting damage then you should be fine.

if someone more knowledgeable can explain better or correct me Id really appreciate it

yeah, the volume was not high thank god but the fact that it was a clipped signal had me worriying i may have done somthing , but all seems fine now, but it is interesting if a 'representation' of a clipped waveform will potentialy to damage, as that what it was really , it was basically a square wave being fed into the preamp, then main amp and coming through the speakers. but the main amp was not clipping , just the signal being fed through if you know what i am getting at , surley this must be a common mistake by newbies, but cretins like me should know better, but the room was dark *blush*

Your right in that the amp section of your integrated saw a square wave and just amplified it ( lol ). Or at least it was an almost square waveform because of the clipping, the HiFi God is forgiving, though must pay the Gods to get back into good favour. 10 x "what makes you beautiful" by One Direction will make up for your sins.

+ you'll never make that mistake again!

 

[lindsayt]

The capacitor in the tweeter section of the speaker crossover protected the tweeter by shunting the DC content of the square wave onto the woofers which can handle a certain amount of DC.

 

[jcbrum]

The capacitor in the tweeter section of the speaker crossover protected the tweeter by shunting the DC content of the square wave onto the woofers which can handle a certain amount of DC.

This is not strictly accurate. There is no 'DC' content of a fully clipped audio signal. It's still a sine wave (AC) and distorted, but with a power transmission (area under the curve) approaching a DC signal. It's the equivalent heating effect of such a signal which can burn the coil in the driver.

The degree to which a capacitor protects the driver depends on the frequency of the signal.

A large amplitude can also mechanically stress the driver beyond its safe condition.

JC

 

[andyjm]

The capacitor in the tweeter section of the speaker crossover protected the tweeter by shunting the DC content of the square wave onto the woofers which can handle a certain amount of DC.

Where to start?

There is no DC component in a square wave symmetrical around 0v which would be the case with a clipped waveform.

Capacitors present an infinite resistance to DC and therefore aren't going to 'shunt' DC anywhere.

The best way to fry a woofer is to supply it with DC.

 

[jcbrum]

It's perfectly ok to feed a 'square wave' signal to a driver providing it does not exceed the driver's maximum power dissipation and excursion parameters.

JC

 

[Covenanter]

ROFL

Chris

 

[andyjm]

It is a good question why a clipped signal blows tweeters - clearly there must be significant high frequency energy coming from somewhere as low frequency signals are blocked by the crossover.

You can either take my word for it, or Google 'Fourier analysis', but a square wave is in fact made up of an infinite series of decreasing amplitude odd harmonic sine waves. The upshot is that even a low frequency square wave will have a very significant high frequency component.

An amp driven into clipping produces large amounts of high frequency energy and it is this that cooks the tweeters.

 

[lindsayt]

OK, be pedantic if you want.

 

[andyjm]

OK, be pedantic if you want.

I guess that by 'pedantic' you mean 'correct'?

 

[jcbrum]

. . . a square wave is in fact made up of an infinite series of decreasing amplitude odd harmonic sine waves. The upshot is that even a low frequency square wave will have a very significant high frequency component.

An amp driven into clipping produces large amounts of high frequency energy and it is this that cooks the tweeters.

A square wave is simply a square wave. It can be mathematically resolved into an infinite series of sine waves, but the reality is that a true square wave simply requires an infinite bandwidth, which of course is not practically available.

Therefore, true square waves don't exist, except as a mathematical concept.

Practical square waves are simply heavily distorted sine waves with a very large and extended hf content, hence the tweeter problems.

JC

 

[peterpiper]

and what about certain recordings that have these types of nasty clipping signals deliberatly mixed in as part of the music , not that I would listen to that type of music (if you can call it music), could that damage tweeters if played loud enough ?, even though the amp itself maybe no where near its limit,

was it dylan/hendrix who deliberatly had their guitar pre- amps overloading for that raw distorted sound

 

[TrevC]

The capacitor in the tweeter section of the speaker crossover protected the tweeter by shunting the DC content of the square wave onto the woofers which can handle a certain amount of DC.

*wacko*

 

[jcbrum]

and what about certain recordings that have these types of nasty clipping signals deliberatly mixed in as part of the music , not that I would listen to that type of music (if you can call it music), could that damage tweeters if played loud enough ?, even though the amp itself maybe no where near its limit,

Simple answer, yes.

But you can damage your tweeters with any signal, if you play it loud enough !

Usually, on a normal audio spectrum, the mid/bass drivers go first, because there's not a lot of hf power in 'normal' music.

JC