[Elecraft] K3s Internal Speaker

[Steve Ellington]

If the washers are one micro too thick, air leaks around the speaker
degrading the sound.
If the washers are one micro too thin you can warp the speaker.

The cure is to have a spacer between the speaker and the lid.  No air
should leak. I think of something like a spacer for PC fans or a
carburetor/manifold gasket. Just something stamped out of cardboard would
be fine.

Steve N4LQ


On Sat, Dec 5, 2015 at 7:51 PM, Wayne Burdick <n6kr at elecraft.com> wrote:

> Thanks, Ron. I'm also going to look into the thickness of the fibre
> washers. They're supposed to be as tall as the cone to prevent bending.
>
> 73,
> Wayne
> N6KR
>
>
> On Dec 5, 2015, at 1:59 PM, "Ron D'Eau Claire" <ron at cobi.biz> wrote:
>
> > Hi Steve. Ron (Tech writer) AC7AC here.
> >
> > After r/r the speaker in a K3, K3 and K3S many times, I have managed to
> make
> > little dimples in the frame ears around the lock washers and nuts. But
> that
> > does not damage the performance of the speaker.
> >
> > As you probably know, the distortion and buzzing occurs with the voice
> coil
> > attached at the center of the cone rubs against the magnet. That happens
> > when the entire frame is distorted.
> >
> > Such distortion can result from aggressively tightening the mounting
> screws
> > so that the ring were the voice coil is attached is bent, which is why
> the
> > warning in the assembly procedure. But it takes being very aggressive.
> >
> > It can happen as a result of handling too, particularly if the speaker is
> > dropped, even when in its box. The magnet is heavy enough that it can
> bend
> > the frame members supporting the magnet on impact. I did that once right
> on
> > my workbench.
> >
> > It sounds like the factory accidentally may have sent you a defective
> > speaker, since you obviously are aware of the distortion issue. Or it's
> > possible the box containing the speaker was the victim of a shipping
> company
> > "gorilla" dribbling it across the sorting table. Elecraft packages
> shipments
> > very well, but I never underestimate the abilities of shipping companies,
> > Hi!
> >
> > 73, Ron AC7AC
> >
> >
> >
> > -----Original Message-----
> > From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of
> Wayne
> > Burdick
> > Sent: Saturday, December 5, 2015 12:11 PM
> > To: Steve Ellington
> > Cc: elecraft at mailman.qth.net
> > Subject: Re: [Elecraft] K3s Internal Speaker
> >
> > Hi Steve,
> >
> > Sorry to hear about this. I've never heard this complaint before (and
> there
> > are tens of thousands of these speakers in use, in both the K3 and K3S).
> The
> > frame should not bend if the correct fibre washers are used and the
> hardware
> > is not over-tightened. I'll check with our manufacturing lead to see if
> the
> > wrong ones were shipped.
> >
> > I'll also check with our tech writer. Perhaps the instructions could be
> > clarified.
> >
> > The internal speaker is certainly of high quality, so I hope you can get
> one
> > installed (I'm sure customer support will send another, given your
> issues).
> > It has excellent sensitivity (95 dB SPL, due in part to the very large
> > shielded magnet) and a wide frequency response range. Given the large top
> > cover mounting surface, the internal speaker is quite loud, with a low
> > natural resonance point.
> >
> > 73,
> > Wayne
> > N6KR
> >
> > On Dec 5, 2015, at 11:59 AM, Steve Ellington <steven4lq at gmail.com>
> wrote:
> >
> >> I've made 2 attempts to install a speaker in my new K3s but they bend
> >> like butter and distort. I was very careful to use the fiber washers
> >> and to not over tighten the bolts. The frame of the speaker can bent
> with
> > 2 fingers!
> >> I've never seen such a flimsy speaker.
> >>
> >> I had a brand x speaker in the junk box that worked great but I wanted
> >> it to be original especially since the speaker is necessary to hold
> >> down the sub receiver's shield. The junk speaker worked fine while I
> >> awaited a replacement but the new  replacement did the same. Basically
> it
> > is junk.
> >> I wonder if they washers they sent are too thin?
> >>
> >> I never use the internal speaker anyway but feel like it should at
> >> least work.
> >>
> >> Has anyone else noticed this? Otherwise I love the K3s!
> >>
> >> Steve N4LQ
> >
> >
> >
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> > delivered to ron at elecraft.com
> >
>
>