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KX3 speaker: distortion from mechanical vibration?

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Andrew Moore-3

KX3 speaker: distortion from mechanical vibration?

My KX3's speaker audio starts to distort as higher volumes at certain
frequencies. It's pretty clear that it's a mechanical vibration, and I can
dampen it by doing things such as applying pressure to the left lever of
the paddle, or gently pressing on the grille. I'm aware of the AGC
threshold adjustment, but that doesn't appear to be the problem.

I've tried adjusting the speaker mounting screws and blowing compressed air
gently into the speaker to make sure there's no debris in there.

Any other suggestions? Should be relatively easy to fix. Maybe a thin
rubber gasket between the speaker and the enclosure would do it.

I really like the internal speaker and would like to use it, as opposed to
an external one.

I love this rig!

--Andrew, NV1B
..
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Don Wilhelm-4

Re: KX3 speaker: distortion from mechanical vibration?

Andrew,

That small speaker - if driven to high volumes *will* distort - there is
nothing that can be done about that.
As far as the mechanical vibration, that is quite another thing.
Look all around the speaker mounting plate - there should be a gap
between that plate and the bottom cover. Be certain you can drag a
sheet of paper into the gaps - if the paper is tight, a bit of filing
(or forming) may be in order to widen the gap.

If there is already an adequate gap, please let us know that too -
Elecraft is searching for the source of this mysterious vibration.

73,
Don W3FPR

On 7/19/2012 11:15 AM, Andrew Moore wrote:

> My KX3's speaker audio starts to distort as higher volumes at certain
> frequencies. It's pretty clear that it's a mechanical vibration, and I can
> dampen it by doing things such as applying pressure to the left lever of
> the paddle, or gently pressing on the grille. I'm aware of the AGC
> threshold adjustment, but that doesn't appear to be the problem.
>
> I've tried adjusting the speaker mounting screws and blowing compressed air
> gently into the speaker to make sure there's no debris in there.
>
> Any other suggestions? Should be relatively easy to fix. Maybe a thin
> rubber gasket between the speaker and the enclosure would do it.
>
> I really like the internal speaker and would like to use it, as opposed to
> an external one.
>
> I love this rig!
>

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Andrew Moore-3

Re: KX3 speaker: distortion from mechanical vibration?

On Thu, Jul 19, 2012 at 1:14 PM, Don Wilhelm <[hidden email]> wrote:

> That small speaker - if driven to high volumes *will* distort - there is
> nothing that can be done about that.
> As far as the mechanical vibration, that is quite another thing.
>

I'm definitely not reaching the speaker's limits, as I can get very clean
output from it at even higher volume as long as I apply pressure to parts
of the case to dampen the vibration.

The speaker itself is no slouch.

I've got to do more checking on this mention of the "gap" so I can be sure
where it's supposed to be. It looks like the square mounting gasket is snug
right up against the enclosure at the moment but it's not clear to me if
that's where this gap is supposed to be. I expect a quick Internet search
will reveal the answer, so I'm off to do that.

Thanks,
--Andrew
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Don Wilhelm-4

Re: KX3 speaker: distortion from mechanical vibration?

Andrew,

The gap is between the top and bottom covers - turn the KX3 over and
look at the bottom right below the speaker - you should see a gap
between the bottom cover and the speaker mounting plate which is a part
of the top cover.

Use a piece of paper as a feeler gauge to be sure the gap is really a
gap and not two pieces of metal touching each other.

73,
Don W3FPR
On 7/19/2012 2:48 PM, Andrew Moore wrote:

> On Thu, Jul 19, 2012 at 1:14 PM, Don Wilhelm <[hidden email]> wrote:
>
>> That small speaker - if driven to high volumes *will* distort - there is
>> nothing that can be done about that.
>> As far as the mechanical vibration, that is quite another thing.
>>
> I'm definitely not reaching the speaker's limits, as I can get very clean
> output from it at even higher volume as long as I apply pressure to parts
> of the case to dampen the vibration.
>
> The speaker itself is no slouch.
>
> I've got to do more checking on this mention of the "gap" so I can be sure
> where it's supposed to be. It looks like the square mounting gasket is snug
> right up against the enclosure at the moment but it's not clear to me if
> that's where this gap is supposed to be. I expect a quick Internet search
> will reveal the answer, so I'm off to do that.
>
> Thanks,
> --Andrew
> ______________________________________________________________
> Elecraft mailing list
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Andrew Moore-3

Re: KX3 speaker: distortion from mechanical vibration?

In reply to this post by Don Wilhelm-4

Ron - I believe they mean this one (and similarly the one on the left side
of the speaker)

*i47.tinypic.com/66chg3.jpg*
*
*
On Thu, Jul 19, 2012 at 3:04 PM, Ron D'Eau Claire <[hidden email]> wrote:

> What gap?
>
> 73, Ron AC7AC
>
>
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Don Wilhelm-4

Re: KX3 speaker: distortion from mechanical vibration?

Ron,

No that is not the one I was referring to (although that may be a
possible candidate too).
Actually, I have zero gap at that location and all else along that edge
between the top and bottom covers. It looks to me as though your bottom
cover is not fully seated - you should not be able to get paper in
there. Also the bottom cover should not stick out further than the
metal that the speaker is mounted on.

Could you please put the photos I sent to you on that "tinypic" site. so
all interested might take a look.

73,
Don W3FPR

On 7/19/2012 3:28 PM, Andrew Moore wrote:

> Ron - I believe they mean this one (and similarly the one on the left side
> of the speaker)
>
> *i47.tinypic.com/66chg3.jpg*
> *
> *
> On Thu, Jul 19, 2012 at 3:04 PM, Ron D'Eau Claire <[hidden email]> wrote:
>
>> What gap?
>>
>> 73, Ron AC7AC
>>
>>
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Don Wilhelm-4

Re: KX3 speaker: distortion from mechanical vibration?

Sorry, that should have been "Andrew" rather than Ron

On 7/19/2012 3:46 PM, Don Wilhelm wrote:

> Ron,
>
> No that is not the one I was referring to (although that may be a
> possible candidate too).
> Actually, I have zero gap at that location and all else along that edge
> between the top and bottom covers. It looks to me as though your bottom
> cover is not fully seated - you should not be able to get paper in
> there. Also the bottom cover should not stick out further than the
> metal that the speaker is mounted on.
>
> Could you please put the photos I sent to you on that "tinypic" site. so
> all interested might take a look.
>
> 73,
> Don W3FPR
>
> On 7/19/2012 3:28 PM, Andrew Moore wrote:
>> Ron - I believe they mean this one (and similarly the one on the left side
>> of the speaker)
>>
>> *i47.tinypic.com/66chg3.jpg*
>> *
>> *
>> On Thu, Jul 19, 2012 at 3:04 PM, Ron D'Eau Claire <[hidden email]> wrote:
>>
>>> What gap?
>>>
>>> 73, Ron AC7AC
>>>
>>>
>> ______________________________________________________________
>> Elecraft mailing list
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Andrew Moore-3

Re: KX3 speaker: distortion from mechanical vibration?

In reply to this post by Don Wilhelm-4

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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KU7Y

Re: KX3 speaker: distortion from mechanical vibration?

I do not have any trouble with buzzing.

Looking at the speaker, the left side of the bottom cover is tight against
the top cover. On the right side, there is a small gap, just about a loose
fit for a piece of paper.

The speaker mounting tab is well away from the left half of the radio case
but the right half has only enough room for the same piece of paper.

Just posting this to provide another data point.

OK, back in my hole,

Ron, KU7Y
SOWP 5545M
Arizona Outlaws Contest Club
Brenda, AZ (Winter)
Caldwell, ID (Summer)
[hidden email]
http://www.hatpinsandmore.com
KX3 #0062

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