# Fan noise, how to judge it?



## maikeldepotter

Fan noise, how to judge it?

Since I have been enjoying my Panasonic PT-AE2000 which I bought some 8 months ago, I have been wondering whether the fan noise was (1) too loud by my own subjective judgement, and (2) too loud when compared to the specifications. 

The latter of course influencing the first, since if you suspect your projector is producing too much noise when compared to the specs, you will have difficulty not to notice it all the time and you will be less happy (and maximizing our hapiness is what we all aim for in the end, no matter how long the road..... )

I could not find much discussion on this subject so that's why I started this thread. Some of the questions that relate to this subject are:
- By which method the specified fan noise dB values are derived?
- Is there a simple and cheap way to objectively measure your fan noise and compare it to specs?
- What do we now about the variability between different samples of the same projector?
- What are the possible causes of such variability?

Since I am throwing the first ball here are some of my observations:
- The specifications of the PT-AE2000 claim a fan noise of 22 dB in eco mode
- a large number of reviews confirm the relatively low fan noise of this projector (subjectively)
- When I had the projector just beside sitting on the couch the fan noise was hardly noticable. Now it is hanging upside down 1,5 meter above my head and the noise is definitely present
- There is hardly any difference in fan noise between normal end eco mode
- The projector produces more fan noise than my PS3 (a well known noise-maker) standing 2 m away on the floor
- my wife does not find the fan noise really disturbing, I definitely do!

Thanks in advance for contributing/ helping out.

Maikel.


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## tonyvdb

How far away from the ceiling is the projector mounted? you may have some reflection of the fan sound off of the ceiling. To solve this if you have the space place some sound absorbing material (a piece of carpet or foam) above the projector where the fan is. Also does the fan vent air out the back/side or the top, the side facing down?


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## Blaser

Hello,

I don't think fan loudness should be compared to the specs. Indeed if it is as per specs and too loud for one's taste some insulation has to be done anyway...

You don't have professional power amps Maikel...do you?


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## maikeldepotter

tonyvdb said:


> How far away from the ceiling is the projector mounted? you may have some reflection of the fan sound off of the ceiling. To solve this if you have the space place some sound absorbing material (a piece of carpet or foam) above the projector where the fan is. Also does the fan vent air out the back/side or the top, the side facing down?


The projector is hanging 8 cm from the cieling. The vent air outs are at the front of the projector. The noise seems to come from inside the project: it is equally loud whether I put my ears near the intake or exhaust ports. I would prefer not needing to place material between projector and cieling for esthetic reasons. Also, when trying it this morning, it didn't not seem to have any effect on the noise level. If I can find time today, I will take the projector form the cieling and try if the noise reduces when I turn it.


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## maikeldepotter

Blaser said:


> Hello,
> 
> I don't think fan loudness should be compared to the specs. Indeed if it is as per specs and too loud for one's taste some insulation has to be done anyway...
> 
> You don't have professional power amps Maikel...do you?


Well, I agree. The question I have at the moment is whether this unit is producing more noise then it should, which could be a reason to have it fixed by the supplier within the garanty period. Prior to this projector I had its predecessor (the pt-ae1000) which I could hardly hear when sitting next to it! The specs for fan noise are the same!

About the equipment: I am using two ROTEL RB-981 power amplifiers together with the outlaw 990 now. :yes:


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## mechman

1. Can you hear the fan running while you're watching TV/Movies/etc.?

2. Does it bother you?

For my Mitsubishi HC3000u, I sit directly underneath it while viewing. And my answer's would be no and no. :bigsmile:

If you can hear the fan and it bothers you I can understand some concern.


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## maikeldepotter

mechman said:


> 1. Can you hear the fan running while you're watching TV/Movies/etc.?
> 
> 2. Does it bother you?
> 
> For my Mitsubishi HC3000u, I sit directly underneath it while viewing. And my answer's would be no and no. :bigsmile:
> 
> If you can hear the fan and it bothers you I can understand some concern.



My answer would be yes and yes. Considering that according to specs your Mitsubishi should even be louder than my Panny (25 dB vs 22 dB), and assuming your hearing is equal to mine, something must be wrong here. To be continued...


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## maikeldepotter

Update: 

Yesterday evening I took the Panny down from the cieling, put it on a small carpeted table, and did some tests. 

I listened to the fan noise of the projector in normal position, compared to the up-side-down position (like when it is attached to the cieling). Conclusion: Neither I, nor my wife could hear any difference in fan noise as a result of the projectors position. 

Then I noticed an additonal ventilation grille at the bottom of the projector close to the air intake for the lamp ventilation, which is placed at the back of the projector. This opening is not mentioned in the manual. Odd thing is that through these openings some air is being sucked in without passing a dust filter, to be joined with the air from the "official" air intake which is filtered. Strange...

Anyway, the thing is that when I covered this seemingly useless ventilation grille with my hand, the fan noise was reduced with about 1/3, at least that is how both me and my wife interpreted it. I think the difference will be bigger when I get the Panny back on the cieling again, as this noise is bouncing back from the cieling, just 3 inches away. Covering it will certainly make a difference.

Now I know what all you are thinking: Is this guy stupid? Covering a ventilation opening on his projector? Well as I said, to me it seems redundant since there is another, filtered ventilation opening next to it which is supposed to do the job, that is: cooling the lamp. Worst thing that can happen is that the projector shuts down because of temperatures getting to high... right?

To be continued...


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## Keith from Canada

maikeldepotter said:


> Fan noise, how to judge it?
> 
> Since I have been enjoying my Panasonic PT-AE2000 which I bought some 8 months ago, I have been wondering whether the fan noise was (1) too loud by my own subjective judgement, and (2) too loud when compared to the specifications.
> 
> The latter of course influencing the first, since if you suspect your projector is producing too much noise when compared to the specs, you will have difficulty not to notice it all the time and you will be less happy (and maximizing our hapiness is what we all aim for in the end, no matter how long the road..... )
> 
> I could not find much discussion on this subject so that's why I started this thread. Some of the questions that relate to this subject are:
> - By which method the specified fan noise dB values are derived?
> - Is there a simple and cheap way to objectively measure your fan noise and compare it to specs?
> - What do we now about the variability between different samples of the same projector?
> - What are the possible causes of such variability?
> 
> Since I am throwing the first ball here are some of my observations:
> - The specifications of the PT-AE2000 claim a fan noise of 22 dB in eco mode
> - a large number of reviews confirm the relatively low fan noise of this projector (subjectively)
> - When I had the projector just beside sitting on the couch the fan noise was hardly noticable. Now it is hanging upside down 1,5 meter above my head and the noise is definitely present
> - There is hardly any difference in fan noise between normal end eco mode
> - The projector produces more fan noise than my PS3 (a well known noise-maker) standing 2 m away on the floor
> - my wife does not find the fan noise really disturbing, I definitely do!
> 
> Thanks in advance for contributing/ helping out.
> 
> Maikel.


Ceiling mounting will increase fan noise...not sure why but it does and most projector manuals will tell you that.

I guess my question is how long have you had your projector up and running? I noticed the fan noise on my Mitsubishi and it bugged me at first. Now I don't notice it at all. As long as the fan sounds like a fan (a gentle 'whir' as opposed to a 'whine'), it shouldn't bother you for long.

If you want to do a scientific test to see how far off spec it is, a sound-level meter from The Source should do the trick.


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## maikeldepotter

Keith from Canada said:


> Ceiling mounting will increase fan noise...not sure why but it does and most projector manuals will tell you that.
> 
> I guess my question is how long have you had your projector up and running? I noticed the fan noise on my Mitsubishi and it bugged me at first. Now I don't notice it at all. As long as the fan sounds like a fan (a gentle 'whir' as opposed to a 'whine'), it shouldn't bother you for long.
> 
> If you want to do a scientific test to see how far off spec it is, a sound-level meter from The Source should do the trick.


Thanks for your reply Keith,

Most cielings have very reflective surfaces for sound. This will increase the fan noise from a cieling mounted projector, especially when there is an vent opening (intake or outlet, doesn't matter) on the side that is facing the cieling. My projector is also very close to a reflective wall behind it. This also doens't help in keeping the noise down, having large vent openings on that side of the projector.

I have had my projector up and running for about 6 months now. The reason for me to look into the fan noise has more to do with my ambition to optimize my set-up in every way thinkable. When I would listen to my present fan noise with the believe that it cannot be reduced, it would not bother me. Just believing that it should be less, or could be reduced, makes me wanting less noise.

Yesterday evening I did some measurements with a professional sound meter from my work. Having the projector placed up-side-down on a small table, I measured the sound at four positions from a distance of about 0,85 meter, the microphone pointed towards the projector in a downward angle of 30 degrees. Background noise level at that time measured 20 dB. The average measurement with the projector running was 33 dB, and with the upper grille covered about 31,5 db. Corrected for the background noise this gives 29,5 and 28,4 dB respectively. The specification value is 28 dB. I did these measurements in a room with reflective walls, which is not according to a standard measurement. Therefore, I believe not to have found evidence to suggest that my projector is out of specs. I will repeat these measurements this weekend with the lamp in ECO mode. This should reduce the noise level with 6 dB. When I have confirmed this, I will put the Panny back on the cieling, and will do some measurements at my viewing/listening position in order to asses the "cieling effect".

To be continued...


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## maikeldepotter

maikeldepotter said:


> To be continued...


... Last night I did some additional noise measurements for assessing the effect of the ECO lamp mode. The projector was in now normal upright position, with the "redundant grille" mentioned earlier (now being on the bottom) covered with a piece of cardboard (a minus 1 dB effect). I had a videocamera running for playback in order to be able to allow for switching from NORMAL to ECO playback mode. The sound coming form the camera was muffled with some pillows. Other conditions were as decribed in previous post. Background maesurement now was 22 dB (being earlier in the evening, and having a videocamera running increased the background noise with about 2 dB). The corrected level with the projector running in NORMAL mode was 28.8 dB. Putting the lamp in ECO mode brought this value back to 27.1 dB. Compared to the 22 dB claimed by Panasonic this is way out of spect IMO. 

Now, I am not sure where the 28 dB specification for the NORMAL mode is coming form Panasonic. I found the value only on a few sites: 1) http://en.buchmann.ch/products/Panasonic_PT-AE2000_Full_HD.htm 2) http://www.bmh.no/shop/index.php?page=shop.product_details&flypage=shop.flypage&product_id=521&category_id=104&manufacturer_id=0&option=com_virtuemart&Itemid=15&vmcchk=1 3) http://www.lyd-billed.dk/produkter/projektor/panasonic_pt-ae2000.htm. So it could be that I am taking measurements that for some reason are 5 dB too high. While I am working with a calibrated sound level meter, my room is not a sound lab.

However, what remains clear and has been reinforced by these measurements is the very small difference between NORMAL and ECO mode with my current projector. Although I can clearly hear the noise reducing when switching to ECO mode, I cannot hear the difference in a blind test: walking into the room where the projector is already running, and be able to tell what MODE it is in by merely listening to the fan noise. 

I would like very much like to hear from other PT-AE2000 owners if you can easily determine the LAMP MODE in such a blind test. Other comments, remarks, insights are welcomed as well. Thanks in advance...

ADDING LATEST EXPERIENCE:

After writing my post above I mounted the projector (with the mentioned grille covered) back on the cieling for watching the movie "Brokeback Mountain" together with my wife. When everything was set-up I listened to the fan noise and concluded that it was still too loud. Then I switched from NORMAL to ECO lamp mode and I was happily suprised. The noise reduced to a level that was very acceptable to me! Even in silent scenes it really didn't distract me as it did before. What happened?! Is the covered grille making the difference? Has my hearing been changed? Have I become less of a sorehead after all the testing? I will do some final measurements today or tomorrow with the projector mounted. As for now.... I am a happier man!!!! :bigsmile:


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