# How noisy is your projector?



## gsmollin (Apr 25, 2006)

This problem surfaces repeatedly in forum posts. The noise from projector fans are a constant issue, and just how noisy are they really? The Radio Shack Sound Level Meter is an inexpensive tool for the hobbyist, but it has a minimum sensitivity of 50 dB, too high to measure a modern projector fan at the standard 1 meter distance, or at your viewing seat. But, the meter has an analog output, and if you connect an inexpensive true RMS DMM to that, you can extend the sensitivity down to 30 dB, or lower.

Calibrate the DMM against the meter readout, using a source of sound. I used an air conditioner fan. Set the RS meter to A weighting, 60 dB range, and slow response. Set the DMM to AC volts. My meter read 0.230 VRMS at 60 dBA. Call this reading "V60". Now set up at the projector. I put the RS meter 1 meter from the edge of the projector, in the direction of my seating area. The meter must be secured by a stand to get consistent readings. Do not stand near it while taking measurements, or reflections from your body can affect the reading. Take a background reading. You may have to go around and shut off noise sources, such as air conditioning, fish tank pumps, computer fans, and fluorescent lamp ballasts. You may also have to wait until 2 AM for traffic to die down. Record your lowest room-measurement voltage, and call it "Vr". My reading was 0.012 VRMS. Convert this to dB by using the formula:


```
dB = 20 * log (Vr / V60) + 60.           (1)
```
My room was 34 dBA, not all that quiet, but it wasn't 2 AM either.

Now turn on the projector and take a second reading. Call this reading "Vp". You can convert that to dB using (1) above. My reading was 0.015 VRMS, which converted to 36 dBA.

Now we must subtract the room background from the projector noise to get the sound level of the projector by itself, as if it were in an anechoic chamber. We do this by subtracting the equivalent power levels of the two readings, using a root-sum-square method. This result is ratioed to V60, and converted to dB as before.


```
dB = 20 * log [ sqrt ( Vp * Vp - Vr * Vr ) / V60 ] + 60.     (2)
```
My result was 32 dBA. If you need more fan noise to get a measurement, you can move the meter closer to the projector. At 1/2 meter, I got a result of 37 dBA. Inverse-square law theory tells us the measurement should increase 6 dB for halving the distance to the source. The 5 dB change indicates this is true, but the measurement becomes sensitive to exact placement and near-field effects that may interfere with the inverse-square-law relationship. Also, halving the distance to the edge of the projector does not halve the distance to the noise source, which is recessed inside the projector case.

I find this projector audible when I sit through quiet passages. My seating area is on the exhaust side of the projector, which makes it worse.

I hope this helps somebody measure and compare their projector fan noises. Remember that the rated levels are taken in an anechoic chamber. A normal listening room has many reflective surfaces, which raise the noise level. It is unlikely you will equal the manufacturer's specified sound level.


----------



## mechman (Feb 8, 2007)

I have always run my projectors in 'eco' mode and I have never noticed noise from them at all when using 2D. And I sit right underneath it. 

I do notice a little bit of fan noise when going to 3D mode with my Epson 3010. It comes out of eco mode then so that you get the extra brightness.


----------



## Anthony (Oct 5, 2006)

My Sanyo Z4 was inaudible in ECO mode, but I have to bump it out of that for any daytime viewing.

However, most of that viewing is sports (movies are usually at night), so the noise doesn't bother me. I barely notice it.


----------



## tonyvdb (Sep 5, 2007)

My Panasonic AE4000 is always in high altitude mode as heat is the worst thing for a projector. That means the fan runs full all the time. I only hear it if I sit in my back row as the noise is much more audible out the back of the projector and its a sacrifice I will make to have it last much longer. it is mounted just behind the front row above my head (I have 9ft ceilings in my basement)


----------



## dsm1212 (Nov 23, 2012)

I just replaced a mitsubishi hc5000 at 19dB (Eco) with a Sony vpl-hw50es at 21dB and I do notice a difference. Actually the model is new and it has a defect with a couple caps in the 3d emitter. When 3d kicks in it creates a high pitched noise. Sony has provided an external emitter for anyone that complains and it turns off the bad caps. Fantastic unit now that I'm past this issue. The mitsubishi in white is for sale by the way in MA/NH area if anyone is interested pm me.

Steve


----------



## rubbersoul (Nov 12, 2007)

I have the Mitsubishi HC 6800 sit right underneath the thing and except for a small amount of and really unnoticeable fan noise it's quiet as all that. I used too have the Infocus Screenplay 5200 which was noisy.

Sent from my iPhone using HTShack


----------



## rac254 (Nov 27, 2012)

I have an AE 7000 that I sit directly underneath and a relatively low mount. It is audible if I'm looking for it but I've never noticed the noise while watching a movie. Only time I've noticed it is when the fan turns off after the projector shuts down and everything else in the room is dead quite.


----------



## 86eldel68-deactivated (Nov 30, 2010)

My JVC DLA-HD250 is whisper-quiet. I love it!


----------

