amp hiss impact on speakers

IMHO, this would lead over some extensive time to a premature aging of the part.

Hi Davey,

It seems to me to be self-evident that there must be **some** power level, other than zero, below which continuous application of that power to a tweeter will not significantly affect its longevity. Assuming, of course, that the frequency content of that power is within the tweeter’s rated bandwidth.

Based on the assumption I stated earlier, that the hiss level the OP described corresponds to an SPL of 40 db at 1 meter (and I would feel pretty certain that the actual number is much less than that), and based on the specified parameters for the tweeter I used as an example (which is used in a small stand-mounted speaker), it would mean that the tweeter is being driven by one five-millionth of its rated power handling capability.

Given the assumption that there is **some** power level, other than zero, below which continuous application to a tweeter will not significantly affect its longevity, it seems to me to be a very safe assumption that one five-millionth of rated power handling capability is small enough. And again, the actual number in this case is probably much less than that.

Regards,
-- Al

@almarg   Intersting post. On my ss amp, if i listen very closely to the tweeter, even with the amp in the off mode( which in this amps case still is actually in the stand by mode...unless it is actually unplugged from the wall) I can also hear this very very faint hiss. I disconnect the bi-wire cable that connects to the tweeter side in this case, while leaving the bass connection still attached, and the hiss goes away. No issues. 
However, if I were to leave the connection, and I suspect this is what the OP is asking about, the tweeter would actually be playing 24/7. While it is clearly NOT being over driven...far from it, like you stated, the tweeter motor is still active. IMHO, this would lead over some extensive time to a premature aging of the part.

Definitely overuse of carbon.

geez, and I presumed only an SR fuse could possibly extend the life of a tweeter.

Tweeters are usually specified as being able to handle many watts, within their specified frequency range. For example consider this datasheet for a tweeter that is used in a very small stand-mounted speaker made by Salk (model WOW1). The datasheet indicates that the tweeter is rated to be able to handle 100 watts when used with an appropriate crossover network that would keep low frequencies out of it.

Since you only hear the hiss when your ear is very close to your speakers it would seem safe to assume that at the usual 1 meter measuring distance the hiss level is **well under** say 40 db. But let’s assume it is 40 db. Given a tweeter sensitivity in the area of say 87 db/1 watt/1 meter, which is the spec on the tweeter I linked to, it can be calculated that the tweeter is producing the hiss in response to an input in the rough vicinity of one fifty-thousandth of a watt, i.e., 0.00002 watts!

The bottom line: It’s a non-issue.

Regards,
-- Al

Oh. M. G.
and I don't say that. 

@millercarbon
Room correction or anything else you mentioned does nothing to get rid of the hiss from the speakers. What will a sub do to get rid of the hiss when it’s coming from the tweeters? Is the person running tube electronics, if so, that is probably the cause.

Right. Good catch. Brilliant! Running tube electronics is definitely the deciding factor. Tip of the hat to you, stereo5! Which tubes do you recommend for the longest tweeter life?

Wait- what? So you mean REL can't cure cancer??? 

😩

Uh, guys it's APRIL FOOLS DAY.

The amp is solid state. With the pre-amp off, I still hear the light hiss. So, the solution is to NOT run the amp the whole time? I keep hearing of people leaving things on "all the time." Is this a mistake, in this instance? 

this is more a case of carbon build up

@millercarbon
Room correction or anything else you mentioned does nothing to get rid of the hiss from the speakers.  What will a sub do to get rid of the hiss when it’s coming from the tweeters?  Is the person running tube electronics, if so, that is probably the cause.  

Even small amounts of endless hiss can build up and potentially eventually heat soak the magnet resulting in loss of gaussian electromotive force and melt the voice coil if continued long enough. Unless ribbons, they simply melt. The solution is auto room correction, GIK panels, and a REL sub, which are so good they can cure cancer.