On Jul 20, 9:01*pm, Jim Adney wrote:
On Jul 20, 2:30*pm, Amanda Ripanykhazov
wrote:

Anyone know what this means? This hissing sound isnt constant, it is
irregular: *It isnt related to the music or any movement of the cone
or any signal put through it, though it doesnt happen when no sound is
put through the speaker.

Frankly it sounds more mechancial than electronic (as if there is
something behind there!) but as I say, it isnt related to whatever is
coming through the speaker though it does increase and decrease with
adjustment of the volume control. *Andit is louder than most signals
put through the woofer itself??

My guess is that the suspension for the woofer cone has come unglued.
This can allow the voice coil to rub on the magnet, which makes sounds
that are mechanical and vary with volume.

To check for this, you'll need to remove the grill cloth so you can
get to the speakers. Gently press all five fingers of one hand against
the woofer cone, next to the center dome. Push sideways on the cone;
try several directions. It should not want to move. It may be useful
to do this on both speaker (stereo, right?) so you can be sure of any
differences.

You may see that the "surround" has disintegrated. That would be an
obvious flaw. There is also a lower support called a spider which
centers the cone near its small end. If the spider has come unglued,
it can be reglued while holding the cone centered.

Older AR speakers used wirewound controls for the tone controls. These
corrode and lose contact. The effect of this is to lose the midrange
or tweeter completely. They can be disassembled and cleaned, but they
don't tend to make extra noises. The capacitors in decent speaker
crossovers are never electrolytics, so they don't generally
deteriorate over time.

I dont know why but the first thing I tried was pushing the cone in to
see if I could identify that rasping effect when a speaker has blown.
Dont know why I did this as the speaker has obviously not blown (the
bass is still quite good. And for some reason I have never
understood, the surrounds in those old speakers aren't made of rubber
which disintegrates so that isnt a problem) in that way but what I
didnt try was to push eccentrically and see if there was any
resistance.

I suspect I am going to have to get them over to Miller Sound at some
time to rebuild (along with a pair of AR3s I have which have badly
corroded cross-overs) but what I was wondering was whether this sound
was likely to make the speaker terminal.

Incidentally the snake behind the woofer is the best description of
what I can actually hear! (a snake with a volume control, that is)