Do low powered amps damage speakers?

[dave2010]

Title .... question...

If so, how?

[Pharos]

If they are driven into clipping yes, the tweeter is in threat.

[dave2010]

If they are driven into clipping yes, the tweeter is in threat.

That's what I heard too, but surely there'd be a lot of distortion if that happened, or can it happen before the distortion becomes audible?

Also, consider electronic/synthesiser music. A lot of that may be composed of sounds made from square waves, other waves etc., white noise - signals from many different parts of the frequency spectrum. If clipping is an issue for speakers, would it not also follow that playing some electronic music could/would also be likely to damage tweeters?

Some speakers also have a response which is above audible hearing range. The way some signal processing works nowadays is to move audio into inaudible regions - couldn't that also damage speakers? Of course it would also depend on an amp also having the ability to pass those sounds out to the transducers.

Or is this business about tweeter damage just an urban myth?

[struth]

i dont believe its being a square waveform that damages speakers.

[Puffin]

I might be talking complete bollox here, but does it make a difference if say a 15w amp has a different gain to a 30w amp or higher. I have used low powered Class D amps to great effect with average sensitivity speakers and been amazed at the amount of grunt they have. As a comparison I was given an original NAD 3020 amp years ago and it was completely gutless and I was really unimpressed. A Creek amp of similar vintage was slightly better, but not that great.

[Filterlab]

Have a read of this article from Mackie (studio equipment manufacturers). It briefly explains how:

https://mackie.com/blog/what-clipping

[Puffin]

Have a read of this article from Mackie (studio equipment manufacturers). It briefly explains how:

https://mackie.com/blog/what-clipping

Nice and succinct and easily understood.

[struth]

i always was under impression that it was when underpowered amps went into clipping etc the distortion of the low freq turned some of it into high freq and it was sent to tweeter or mids and thus blew set drivers that couldnt take such power levels.

So a odd concept that under power producing overpower as it were

[Macca]

I might be talking complete bollox here, but does it make a difference if say a 15w amp has a different gain to a 30w amp or higher. I have used low powered Class D amps to great effect with average sensitivity speakers and been amazed at the amount of grunt they have. As a comparison I was given an original NAD 3020 amp years ago and it was completely gutless and I was really unimpressed. A Creek amp of similar vintage was slightly better, but not that great.

No, it makes no difference.

The NAD only has 20 watts into 8 ohm after all. Maybe the class D clips more gently, so you're still overdriving just not as noticeable? Same with most valve amps.

Obviously will also depend on speaker sensitivity so if you weren't using the same speakers for both then not a fair comparison.

[Beobloke]

That's what I heard too, but surely there'd be a lot of distortion if that happened, or can it happen before the distortion becomes audible?

The problem is that different distortions have different levels of audibility and clipping is a fairly mild one by comparison.

Early in my acoustics career, I was given a demo of the effect of distortion using purposely generated distortion levels of 1% and 10%, and the demo went like this:

- Listen to a 1kHz sine wave - nice and smooth
- Listen to the 1kHz sine wave with 1% distortion added - not so smooth
- Listen to the 1kHz sine wave with 10% distortion added - Awful - ragged and harsh!

The source was then changed to a pierce of music and repeated. This time i heard
- Music with no distortion added - sounded fine
- Music with the 1% distortion added - sounded bad and obviously distorted.
- Music with the 10% distortion added - sounded barely any different to the undistorted signal! Maybe just a touch harder across the top end and with a somewhat curtailed bass, but the results were far less obvious than the 1%

Well obviously this was confusing, but the key was in the type of distortion. To make the 1%, the signal had a deliberate shift in the zero-crossing point of the AC signal introduced. To generate the 10%, clipping was added. The 1% therefore affected every frequency at any signal level, whereas the 10% only affected the peaks and mostly at the bass end.

Basically, unless you're clipping really hard, or really know what you're listening for, clipping isn't always easy to detect.