# 921 Fan/disk sound measurement



## bnam (Nov 25, 2004)

Has anyone measured the sound level from the 921? I just put my SPL meter about an inch in front of the 921 and got a reading of 54dB. I'm wondering if others have measured...

Box is in shelf below my TV open in front and back, has 1.5inch space on both sides and has a CD changer on top

I'm planning to get some baseline readings before I swap out the fan for a quieter unit.

Byas


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## tnsprin (Mar 16, 2003)

bnam said:


> Has anyone measured the sound level from the 921? I just put my SPL meter about an inch in front of the 921 and got a reading of 54dB. I'm wondering if others have measured...
> 
> Box is in shelf below my TV open in front and back, has 1.5inch space on both sides and has a CD changer on top
> 
> ...


my meter doesn't go very low. About 50db is where it starts. From in front of the 921, that close, it read nothing. From the sides, near the vents, it reads about 54db.


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## ClaudeR (Dec 7, 2003)

I only get readings somewhere between "obnoxious" and "deafening". 10 months left on my warranty and counting...


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## GaryBeav (Dec 5, 2004)

bnam said:


> Has anyone measured the sound level from the 921? I just put my SPL meter about an inch in front of the 921 and got a reading of 54dB. I'm wondering if others have measured...
> 
> Box is in shelf below my TV open in front and back, has 1.5inch space on both sides and has a CD changer on top
> 
> ...


I get 56db


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## Zevon (Dec 28, 2004)

I have reduced the noise on my 921 somewhat  by replacing the case fan with a 9db Silenx 80mm unit. However, when I opened up the unit, (forget about the warranty, I want silence!), I noticed another fan, a 60mm unit, over by the CPU, mounted to the front panel. Sure enough, this thing makes most of the noise. :bang

I've got an 8db Silenx fan on order. I'll keep you posted on my success. If you all want, I can post a detailed "how to" if you aren't comfortable with performing the process.

Silenx makes fantastic, quiet fans. I am not affiliated with them in any way, but I have purchased a lot of their stuff and am always impressed.

http://www.silenx.com


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## sll (Jan 6, 2005)

Thanks for the info about a fan replacement. Please do keep us updated as to your success with the fan replacement. A "how to" would also be welcome. The constant fan noise the 921 makes as bugged me for quite some time.


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## mwgiii (Jul 19, 2002)

I am praying for the day Dish adds the code to spin down the HD and turn off the fan when the 921 is in standby.

Dish has this feature in the 5XX DVRs.


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## lujan (Feb 10, 2004)

mwgiii said:


> I am praying for the day Dish adds the code to spin down the HD and turn off the fan when the 921 is in standby.
> 
> Dish has this feature in the 5XX DVRs.


I don't believe it but I finally got through to ask a question on the Technical Chat tonight (2/21/05). I asked if there were any plans to update the software to turn off the fans and hard drive in the future. Dan said that because the 921 is Linux based, the software runs off the hard drive and because the software runs off of it, the hard drive needs to stay on all of the time. Also, because the hard drive is always running, the fan(s) will come on and off because of the heat generated by the hard drive. Maybe someone that is familiar with Linux can explain better than I could here or better than Dan did on the Tech Chat.


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## bnam (Nov 25, 2004)

Zevon,
I'm interested in your results on replacing the fans. It would be great if you could do a before and after. I had replaced the fan on my 6000 (was on the module). I noticed that the replacement fan got noisier over time -- perhaps they were not deisgned to run all the time (?). I don't remember the brand, but I vaguely recall that fans with sleeved bearings were supposed to run quieter.

Gary, was your reading from front or side? 

Byas


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## GaryBeav (Dec 5, 2004)

bnam said:


> Zevon,
> I'm interested in your results on replacing the fans. It would be great if you could do a before and after. I had replaced the fan on my 6000 (was on the module). I noticed that the replacement fan got noisier over time -- perhaps they were not deisgned to run all the time (?). I don't remember the brand, but I vaguely recall that fans with sleeved bearings were supposed to run quieter.
> 
> Gary, was your reading from front or side?
> ...


Byas my reading was from the front with a Radio shack 33-2050 sound level meter I use to set up my surround sound.


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## keitheva (Aug 23, 2002)

I replaced both the fans in my 921.

You can read about it and see pics here,

http://www.dbstalk.com/showthread.php?t=38204

Cheers,
-Keith


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## Zevon (Dec 28, 2004)

keitheva said:


> I replaced both the fans in my 921.
> 
> You can read about it and see pics here,
> 
> ...


I did a search after I wrote my notes above, and found Keith's detailed directions and was going to include a link to it in my next post. Thanks for beating me to it, and saving me the work.

I received my 60mm fan today, and installed it. Got it done without having to mod the fan as Keith indicated, even though it was the same size fan. I was about to take some drastic steps when I realized that the metal frame un-hooks at the front corner where the fan is located, allowing me to gently pry it back far enough to slip the fan in place. Everything went back in without a hitch and I have about 1/4" clearance between the fan and the CPU heatsink.

The unit is absolutely silent now; you can hear the hard drive only if you get really close to it.

If you are comfortable working on PCs, I recommend the upgrade wholeheartedly. If you are nervous about doing this yourself, I recommend you follow the directions Keith has detailed and proceed with EXTREME caution so as not to break anything. The unit basically is a PC, so use the care you would with a PC. If the thought of opening this box up makes you break out in hives, I recommend you get a very experienced PC technician to help you.

Do it, and enjoy the sweet silence.
Warren


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## keitheva (Aug 23, 2002)

Hi Warren,

If you look at the pictures you'll see we have very different looking cpu heatsinks. Dunno if I could have squeezed mine in the way you did or not. Would have been nice to know the trick anyway!

Cheers,
-Keith


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## Zevon (Dec 28, 2004)

I agree. When I look at the one photo of yours that is shot from above, you can clearly see that the fan is almost touching the heatsink. Once I got mine in, there is a 1/4" clearance between them. Must be that they used some different components as the production of the 921 evolved. I bought mine only a couple of months ago.


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## Tomos (Jan 16, 2005)

"The unit is absolutely silent now; you can hear the hard drive only if you get really close to it."

Fortunately thats how my unit is from the factory, don't know if they changed the fans on later units but possibly.


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