speaker distortion

[Arthur Nienhouse]

/*My gap on the right side looking at your first picture vn9 where the
slot is in the upper case half when the case half's are closed I see the
right side touching on the vertical part then on the horizontal bottom
its touching in the lower right
bottom case.

I m going to take a good machinist file and open that vertical gap on
the lower case, thinking about this arrangement the whole mount of the
speaker is on a island of sorts asking to be vibrated like a tuning
fork. And that is exactly what I think my radio is doing.

When touching that lower right corner of the speaker grill opening the
vibration stops as I'm sending cw with the monitor volume up to hear my
fist.

What I think it needs is to keep that bottom of the speaker (island)
from vibrating like a diving board or tuning fork could some kind of
triangle angle bracket inside the upper case to make solid this speaker
area to the upper case of the radio.

Could be what is needed is to anchor that bottom part of the speaker
(island) top case to the lower case half, when the KXPD3 is bolted on
the issue is worse the top of the keyer is vibrating a lot my last post
with out the key mounted the side tone set at 30 there was hardly a
trace of vibrating  applying in ward pressure on the lower right of the
speaker grill stops all vibrating.

It also might be a good thing to bend this lower speaker area in just a
tad before assembling the radio looking at the fit of the case half's
first before stuffing the kit in it.
Any thoughts ...

Regards
Art
ka9zap
*/

On 7/19/2012 3:17 PM, Andrew Moore wrote:

> Don, Ron, Wayne & all--
>
> Looks like the buzzy speaker distortion problem was in fact due to the gaps
> between the top and bottom halves of the enclosure. This may be premature
> as I haven't made a permanent fix but all signs point to these gaps.
>
> Ron, I was wrong in assuming that Don was referring to the gap I
> illustrated - I hadn't seen or considered the one directly below the
> speaker grille - however, the one I illustrated may in fact be part of the
> problem as well.
>
> It seems like we're dealing with two types of distortion: 1) AGC threshold
> too high and 2) mechanical vibration of the KX3's enclosure.  The first
> seems to be solved by going into the menu and setting: a) AGC MD to "ON",
> b) AGC SPD to "FAST" and c) AGC THR(eshold) to "005" (the default used to
> be "007" but Wayne says that should now be "005" as shipped from the
> factory).
>
> The second seems to be solved by focusing on three main gaps between the
> upper and lower enclosure halves. Looking at the KX3 with the speaker
> facing you, one gap is about 4 inches long and is located to the left of
> the speaker; one is about 1.5 inches long and is directly under the speaker
> grille; and one is about 1.5 inches long and is located to the right of the
> speaker.
>
> The solution appears to be either making sure the gap is wide enough so the
> two halves of the enclosure don't contact each other, or actually closing
> this gap by inserting some kind of material that dampens the vibration. In
> my case, I'm going for the latter, and will attempt to use an
> adhesive-backed felt. I think this would be easier than filing, prying,
> bending, etc., and will work with minimal fiddling if the enclosure is ever
> opened up again.
>
> Images illustrating the gaps (two of them courtesy Don W3FPR) follow via
> links below.
>
> Thanks Wayne/Don/Ron/all for helping debug this. Even with my temporary fix
> (fabric stuffed into the gap), the problem is about 90% solved.
>
> This is a very capable little speaker.
>
> Disclaimer... all off the above is to the best of my knowledge and is my
> own experience with one KX3 sample.  I don't speak for Elecraft and this is
> not necessarily an official solution, nor am I saying this was even a
> "problem" to begin with. I'm just trying to make my KX3 behave the way I
> want. Fantastic little rig!
>
> --Andrew, NV1B
>
> Links:
> http://i47.tinypic.com/21l5vn9.jpg
> http://i47.tinypic.com/34pkpvs.jpg
> http://i48.tinypic.com/108a5pi.jpg
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