Re: Resonant mirror noise

Posted by Craig Brideau on
URL: http://confocal-microscopy-list.275.s1.nabble.com/Resonant-mirror-noise-tp7588458p7588471.html

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To add to the chorus, basically the scanners need to be in a sealed
enclosure. It doesn't need to be in vacuum, (although that would really
help) but as long as it cannot transfer sound pressure easily via air it
will be considerably quieter. Note your scan lens becomes the window for
the enclosure; it has quite a bit of spaced glass so it will probably be a
good sound absorber. A little sound dampening foam may still be necessary
on the exterior, just make sure you can still safely dissipate any heat
from the scanners and don't smother the thing completely. I have an early
resonant confocal system that shrieks when in use, and a system which is
newer by a few years, and the newer one is much quieter. On observation,
the new system is simply boxed up better with thicker walls and no gaps
from the interior to the exterior.

Craig

On Thu, Jul 26, 2018 at 8:53 AM Martin Wessendorf <[hidden email]> wrote:

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>
> Dear all--
>
> I'm going to guess that the obnoxiousness of the sound may be a
> function, in part, of the age of the listener.
> See: https://link.springer.com/article/10.1007/s00420-014-0951-8
>
> --Along those lines, I once had a digital watch with an unusually
> high-pitched alarm that I (at age 60) could barely hear, but the sound
> of which drove my sons (in their 20s) crazy.
>
> Martin Wessendorf
>
>
>
>
> On 7/25/2018 9:33 PM, Power, Rory wrote:
> > *****
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> > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> > Post images onhttp://www.imgur.com  and include the link in your
> posting.
> > *****
> >
> > Hi Mike,
> >
> > Thanks for your reply. I was rather referring to an 8 kHz fundamental
> oscillation. The noise is quite unpleasant - I’d hate to hear the 4 kHz if
> that’s worse as you say.
> >
> > Isolation should be possible. Perhaps combined with some foam we’ll
> arrive at a workable system.
> >
> > Yes, I assumed the same. Thanks again.
> >
> > Regards
> >
> > Rory
> >
> > …………………………………………………………
> >
> > Dr. Rory Power
> > HFSP Postdoctoral Fellow
> > Morgridge Institute for Research
> > Medical Engineering | Huisken Lab
> > 330 N Orchard St, Madison, WI, 53715
> > Tel: [phone]
> > [hidden email]<mailto:[hidden email]>
> >
> >
> >
> >
> > On Jul 25, 2018, at 21:18, Michael Giacomelli <[hidden email]<mailto:
> [hidden email]>> wrote:
> >
> > *****
> > To join, leave or search the confocal microscopy listserv, go to:
> > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> > Post images onhttp://www.imgur.com  and include the link in your
> posting.
> > *****
> >
> > Hi Rory,
> >
> > 8 KHz unidirectional or bidirectional (so 4 KHz fundamental)?  The 8 KHz
> > scanners are usually not that bad even at maximum amplitude because the 8
> > kHz tone is a lot harder to hear and essentially all the harmonics are
> out
> > of audible range.
> >
> > For 4 KHz at larger deflection angles you either need hearing protection
> or
> > to really isolate it from the room.  A metal box around the scanner and a
> > window on the input port so that air cannot pass in/out of the scanner
> > helps a lot. This is how most commerical systems work.
> >
> > I don't think the model matters; the noise comes from pushing air, so
> for a
> > given mirror size and deflection angle the noise power is going to be
> > almost constant.
> >
> > Mike
> >
> > On Wed, Jul 25, 2018 at 9:03 PM, Power, Rory<[hidden email]>
> wrote:
> >
> > *****
> > To join, leave or search the confocal microscopy listserv, go to:
> > http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> > Post images onhttp://www.imgur.com  and include the link in your
> posting.
> > *****
> >
> > Hi Confocalists,
> >
> > We’re trying to circumvent the annoyance of resonant mirrors screaming at
> > 8 kHz. I was wondering whether anyone has a recommendation for
> constructing
> > soundproof containment?
> >
> > Generally were using inexpensive resonant mirrors from EOPC:
> > http://www.eopc.com/sc30.html
> >
> > Also, does anyone know whether the more costly resonant scanners used for
> > confocal/multi-photon laser scanning microscopies are any better in this
> > regard? Were not hugely concerned with other attributes (simply for light
> > sheet microscopy stripe suppression) just the piercing noise.
> >
> > Many thanks in advance!
> >
> > Rory
> >
> > …………………………………………………………
> >
> > Dr. Rory Power
> > Morgridge Institute for Research
> > Medical Engineering | Huisken Lab
> > 330 N Orchard St, Madison, WI, 53715
> > Tel: [phone]
> > [hidden email]<mailto:[hidden email]>
> >
> >
> >
> >
> >
> >
>
> --
> Martin Wessendorf, Ph.D.                   office: [phone]
> Assoc Prof, Dept Neuroscience                 lab: [phone]
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>