Panasonic ZT60 and VT60 Fan/Fridge Noise Production Numbers - Page 50 - AVS Forum
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post #1471 of 1484 Old 07-15-2014, 04:52 PM
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Originally Posted by eaayoung View Post
Have you tried increasing the size of the holes? That should reduce the temperature but may not result in a increase in fan noise. It's been suggested the fan noise is not really the fans themselves but harmonics from the rear cover. Just a thought.
When the cover was off, I could not hear the fans.
So it was either that they were horizontal or the cover is adding noise and amplifying vibration.


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post #1472 of 1484 Old 07-15-2014, 07:06 PM
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Originally Posted by eaayoung View Post
Have you tried increasing the size of the holes? That should reduce the temperature but may not result in a increase in fan noise. It's been suggested the fan noise is not really the fans themselves but harmonics from the rear cover. Just a thought.
yes, it does seem to be harmonics. depending where i sit in the room i can hear it or not hear it... really irritating, since the only place i hear it is really the only place i sit in the room 11 feet back from the TV. the pitch is at a frequency that seems to bounce off the walls.

i'll try making another set with wider holes and see how that goes. i guess the ideal way to do this would be to get the temperature as close to possible as not having them.
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post #1473 of 1484 Old 07-15-2014, 07:28 PM
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Room acoustics due to size and shape and how open it is plays a big part too. Among other things like model and size tv. Volum levels, with or without surround sound. All these differing variables is why it's a diffrent reported expierence by everyone.
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post #1474 of 1484 Old 07-15-2014, 07:46 PM
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Originally Posted by RichB View Post
When the cover was off, I could not hear the fans.
So it was either that they were horizontal or the cover is adding noise and amplifying vibration.


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okay, making the hole bigger did make it a bit louder. the hottest the inside of the cover got was 134F.

just how much of a fire hazard is this? or will it burn out the components in the TV faster/prematurely?
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post #1475 of 1484 Old 07-15-2014, 08:44 PM
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okay, making the hole bigger did make it a bit louder. the hottest the inside of the cover got was 134F.

just how much of a fire hazard is this? or will it burn out the components in the TV faster/prematurely?
Bigger holes raised the temperature?

Anyway, have you tried with just one or two of the fans covered? (The center one should be the least noisy one, it is the one that doesn't have any additional foam applied for "the fix".)

Seems to me my set does run hotter/noiser during the summer months, though I don't hear it so much any more, except when I turn it off after turning the receiver (audio) off beforehand. Do have a bit of tape covering the fan exhaust, at the time I put it in place it did seem to reduce the noise a bit (not enough) and didn't seem to matter with respect to how warm/hot the back got.

Like with the other minor annoyances with the set (except for some pesky IR), I don't really pay it much mind any more, but still wouldn't mind a quick fix.
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post #1476 of 1484 Old 07-16-2014, 08:00 AM
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Originally Posted by fmalczewski View Post
Bigger holes raised the temperature?

Anyway, have you tried with just one or two of the fans covered? (The center one should be the least noisy one, it is the one that doesn't have any additional foam applied for "the fix".)

Seems to me my set does run hotter/noiser during the summer months, though I don't hear it so much any more, except when I turn it off after turning the receiver (audio) off beforehand. Do have a bit of tape covering the fan exhaust, at the time I put it in place it did seem to reduce the noise a bit (not enough) and didn't seem to matter with respect to how warm/hot the back got.

Like with the other minor annoyances with the set (except for some pesky IR), I don't really pay it much mind any more, but still wouldn't mind a quick fix.
oh no, making the holes bigger didn't increase the temp, i'm just saying in general the hottest inside one of the foam covers i measured was 134F. i notice that i need to have them all covered to almost eliminate the sound.
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post #1477 of 1484 Old 07-16-2014, 02:48 PM
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oh no, making the holes bigger didn't increase the temp, i'm just saying in general the hottest inside one of the foam covers i measured was 134F. i notice that i need to have them all covered to almost eliminate the sound.
Got it. I had the tv running a bit with no sound earlier today, was actually pretty loud, at least off to the side. But with the avr at normal volume, didn't notice it at all. Probably been a while since a suitably quiet movie has been attempted, it would seem.

(It was a pretty quiet day around here mostly, though my flakey internet made it even quieter for most of the day... brief respite for now...)
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post #1478 of 1484 Old 08-19-2014, 06:14 PM
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Panasonic TC-P65ZT60
MK32940782
October, 2013
A14934

Has fan noise.

From the manufacturing date, would it already have the foam fix? If so, was anything else found that helped?

My system? Google for: Martin Logan 420 CLX Descent Stage Summit
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post #1479 of 1484 Old 08-19-2014, 06:49 PM
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Originally Posted by jimshowalter View Post
Panasonic TC-P65ZT60
MK32940782
October, 2013
A14934

Has fan noise.

From the manufacturing date, would it already have the foam fix? If so, was anything else found that helped?
That date should already have the fan fix in place.

There's a lot of DIY stuff that some has said has helped to quiet the fans.
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post #1480 of 1484 Old 08-20-2014, 09:15 AM
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Originally Posted by Jason626 View Post
That date should already have the fan fix in place.

There's a lot of DIY stuff that some has said has helped to quiet the fans.
I can see the foam "fix" looking at the back of the unit. It does not appear to fix the problem, or at least not fully fix it.

Pushing gently on the back of the panel to the left of the fan on the left (when looking at the back), I can feel it deflect slightly.

That means the back is really a drum. If turbulent flow forms in the exhaust area and happens to sync up with the resonant frequency of the "drum", even tiny initial effects could turn into unacceptably large amounts of noise.

Removing the back would of course make the problem go away. The foam "fix" might, depending on placement of foam, reduce the resonance and thereby the noise, without actually attacking the root cause. (Noise reduction due to the foam "fix" would just be a side effect of the foam.)

Did anyone try adding mass damping to the back of the TV? I'm thinking some thick, heavy blocks of viscoelastic material might snub the oscillations and make the problem go away.

Similarly, chunks of viscoelastic material thick enough to contact both the inside wall and the inside of the back might prevent it from vibrating.

My system? Google for: Martin Logan 420 CLX Descent Stage Summit
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post #1481 of 1484 Old 08-20-2014, 04:48 PM
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Quote:
Originally Posted by jimshowalter View Post

Did anyone try adding mass damping to the back of the TV? I'm thinking some thick, heavy blocks of viscoelastic material might snub the oscillations and make the problem go away.

Similarly, chunks of viscoelastic material thick enough to contact both the inside wall and the inside of the back might prevent it from vibrating.
Not sure that's been tried. Might work since the problem appears to be vibration of the rear cover. I've wonder about whether it would work as well. But I'm lucky since the fans on my 60 ZT aren't loud enough motivate my to find a solution. Let us know if it works.
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post #1482 of 1484 Old Today, 07:46 PM
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Mass damping probably won't work. I pressed on the back pretty hard--certainly hard enough to shut down any vibrations--and it had no effect.

The reason I thought it might be resonance with the back is that the back is made of thin flimsy metal. You can see that by pressing on it. So it would be pretty easy to vibrate.

But now I think it could be beat frequencies among the small amount of sound generated by each fan. Remove the back, the sound radiates spherically from each fan and is dispersed. Leave the back on, the sound is trapped in the layer between the back and the main body of the panel.

If that's true, the various types of airflow diverters don't address the root cause.

The foam "fix", being inside the gap between the back and the main body of the panel could help by acting like small separators. But they're imperfect because they're porous.

Did anyone try isolating the airflows behind the panel with vertical separators, so they can't interact?

My system? Google for: Martin Logan 420 CLX Descent Stage Summit
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post #1483 of 1484 Old Today, 08:56 PM
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Originally Posted by jimshowalter View Post
Did anyone try isolating the airflows behind the panel with vertical separators, so they can't interact?
Not on this forum. Only fix I've read about has been foam, various baffles or the plunger.
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post #1484 of 1484 Old Today, 09:17 PM
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Did anyone try:

- Shutting off all but one fan (briefly). If noise goes away, beat-frequency theory is substantiated.

- Installing inline fan speed control(s).

- Installing larger, slower fans (same CFU, but possibly less noise). Might require external mounting, but so be it.

Also, what have people used to measure before and after temperatures?

My system? Google for: Martin Logan 420 CLX Descent Stage Summit
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