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View Full Version : Re: subtle damage to drivers?


Ethan Winer
August 9th 03, 03:55 PM
Laura,

> i built some speakers recently, if I had damaged the drivers while doing
it, would it be obvious? <

If you didn't actually saw into the speaker cone, or bend the frame out of
shape, then it's probably still fine. Listening to only one driver or the
other won't hurt anything, though you should never send low frequencies to a
tweeter without having a crossover connected. Sending high frequencies to a
woofer should be okay, even without a crossover.

I used to work for a large speaker manufacturer and every driver was tested
by playing a sine wave that swept through the driver's normal operating
range. So if you have access to a sine wave generator or test tone CD, you
can verify that the speaker is okay by slowly sweeping a tone at a moderate
to semi-loud level. What you're listening for is buzzing or obvious
distortion, and you sweep across a range of frequencies to make sure the
driver is okay at all frequencies. For a woofer you'll sweep from it's
lowest rated frequency up to maybe 1 KHz.

--Ethan

Laurence Payne
August 10th 03, 11:43 AM
>It actually sounds beautiful, with woofer and tweeter attached. But i'm
>mostly hearing the woofer.

That's good. The box is meant to sound like one speaker. If you
start specifically hearing the tweeter it's probably distorting.
>
>So, is the tweeter probably ok since i tried it with the crossover
>connected and no
>woofer? It sounded awful that way and at first i thought something had
>gotten messed up. But then i decided, maybe without a woofer attached,
>the crossover lets some low frequencies into the tweeter and causes those
>crackly, hissy noises.

Tweeter alone WILL sound pretty horrible.

Ethan Winer
August 10th 03, 03:59 PM
Laura,

> i have a keyboard. Would that work to test the tweeter and the woofer? I
tried hitting all its keys loud. Everything sounded fine except that there
is an increase in hiss from the tweeter >

If you can play loud and the woofer doesn't distort, then all seems to be
working.

> i'm mostly hearing the woofer. <

Were the woofer, tweeter, and crossover designed to work together?

--Ethan

Ethan Winer
August 12th 03, 05:06 PM
Laura,

> I took the advice of the people in the stereo store on that. <

Okay, then you're PROBABLY okay there.

> is it normal to hear a slight increase in hiss from the tweeter just below
the crossover frequency? <

Any hiss you hear only while you play notes on your keyboard are surely from
the keyboard. In fact, speakers and crossovers by definition cannot create
hiss, only amps and preamps and other electronic devices.

--Ethan

Ethan Winer
August 14th 03, 02:43 PM
Henry,

> If you move air through the right shape of leak, you'll get a "ssss"
sound. <

Great point. I hadn't even considered that.

--Ethan

Arny Krueger
August 14th 03, 06:30 PM
"Henry" > wrote in message


> In article >, "Ethan Winer"
> <ethan at ethanwiner dot com> wrote: <snip>

>>"Lacustral" > wrote in message


>>> is it normal to hear a slight increase in hiss from the tweeter just
>>> below the crossover frequency? mine put out extra hiss with the note
>>> from 1000-2000 Hz. Not terribly loud but quite audible

>> In fact, speakers and crossovers by definition cannot create
>> hiss, only amps and preamps and other electronic devices.

> Ethan, have you considered the possibility of an air leak in a speaker
> enclosure? If you move air through the right shape of leak, you'll
> get a "ssss" sound. Try voicing the "ssss" sound, and you'll see
> what I mean,

Right, but that presumes serious amounts of sound being generated at some
low frequency, which modulates the hiss in a way that is pretty obvious and
diagnostic.

Lacustral seems to be talking about noise at low volumes.