Audio Recording Noise Test on a new laptop.How do I reduce fan/system noise?

[PeterGreen]

Hi,

I'm not sure where to post this but since I came here for info and advice when I wanted to buy a new laptop for audio recording/processing 6months ago I thought just to put this here.

I recently bought a Dell precision M4700. I could find no customer reviews since it just came out last summer but I read one very detailed and overall pretty good review but I was concerned about 1 thing. The review mentioned the noise gets loud with the fans( it has one for the processor and one to cool the graphics card.)
I didn't know then that the fans don't always run. Apparently they start when the processor reaches a certain temperature and stop when the processor has cooled down which I can clearly hear on this recording I just made last week.

I was recording quiet sounds and simultaneously recorded using a dv camera. When I listened back to the audio recording I noticed this extra noise.
At first I thought I had somehow accidentally swapped the audio with the audio from the video camera(I imported audio from both devices in the video editing window) and that has camera noise on it.

Listening to the audio recording track from the beginning I noticed that that noise isn't always there. In the beginning of the track you clearly hear the noise that stops after 10 seconds for 1 minute and then the noise returns at 1'09". So that must be when the fan starts running. I think it's quite loud actually.

The video is uploaded on youtube. link http://www.youtube.com/watch?v=PJ7tMyb-Qh0

Did I make a mistake buying this computer? Does anyone know what I can do to reduce that noise -preferrably before recording - but if not then without doing damage to the actual audio?

[hjorte]

Originally Posted by PeterGreen

Did I make a mistake buying this computer?

No. In general a laptop needs to cool itself by active cooling (in this case a fan) due to the insufficient passive cooling design. They all suffer from this more or less. They are simply too small and crammed to host sufficient passive cooling.

Does anyone know what I can do to reduce that noise without doing damage to the actual audio?

I have no advice for noise reduction of your current example other than carve it out with EQ, but next time around, make sure you place your laptop farther away from the microphone and isolate the two acoustically somehow. I would build a U-shaped acoustically treated box to host the laptop and make the recording in a treated room as well.

[PeterGreen]

Originally Posted by hjorte

I have no advice for noise reduction of your current example other than carve it out with EQ, but next time around, make sure you place your laptop farther away from the microphone and isolate the two acoustically somehow. I would build a U-shaped acoustically treated box to host the laptop and make the recording in a treated room as well.

The noise on this video is not important but for recording music in the future. Building a treated box that's a good idea. Thanks!

[sunburst79]

Its possible that one of those laptop coolers with the fans would help and be quieter than the fans in the unit if you could keep them from turning on when it gets hot.

[jasonthurley]

If it happens during silent parts just duplicate the track... reverse the phase of the 2nd track and only use clips on the out of phase track when you want to remove the fan noise... This will cancel the frequencies out and you wont hear it... although it gets more difficult as you try and remove it with recorded audio. In that case I would use a very good noise reduction software like Isotope RX2.

As far as doing something about the fans while recording there is a way in Windows to adjust the fan speeds and when they kick on, etc... but I do NOT recommend touching these settings as you could have permanent hardware failure If it overheats. The olny alternative it to record the material away from the laptop (in a separate room, or making a homemade baffle to surround the source and microphone. Another that can help a bit is to use a deflector shield around you laptop (similar to an amp or drum shield), this will help the direct signal from being so loud as it diffuses the fan noise.

I have a Macbook Pro I7 and dont really get bothered with fan noise when mixing but If I am recording into a large (heavy plug) session the fans are whistling pretty good... that is just the result of having ANY computer in the same room you record in... even towers I hear fans on recordings done in the same room.

[PeterGreen]

Originally Posted by jasonthurley

... although it gets more difficult as you try and remove it with recorded audio. In that case I would use a very good noise reduction software like Isotope RX2.

As far as doing something about the fans while recording there is a way in Windows to adjust the fan speeds and when they kick on, etc... but I do NOT recommend touching these settings as you could have permanent hardware failure If it overheats.

Thanks for info. I if you use an out of phase track it will cancel out the actual audio too right? I'll look for the Isotope RX2. I got ozone and it's pretty good stuff.
Yea I can't change any fans settings I think, wouldn't if I could cause I already had heating issues within days of purchase. The table I use has a soft surface and cutoff the bottom vents so the palmrest,it already started melting down

[PeterGreen]

Originally Posted by sunburst79

Its possible that one of those laptop coolers with the fans would help and be quieter than the fans in the unit if you could keep them from turning on when it gets hot.

Sorry I don't know those. Do you have any links or specific name/brand I should search?

[hjorte]

There is no way a laptop cooler will be able to cool a PC laptop to the extent that the laptop won't need to switch on its internal fans at some point when doing even low to average CPU/GPU extensive tasks. Disabling the laptop fans (if at all possible) is not recommended.

A laptop cooler is not comparable to and nor is it a replacement for laptop internal fans.

[jasonthurley]

Originally Posted by PeterGreen

Thanks for info. I if you use an out of phase track it will cancel out the actual audio too right?

Exactly... so you could use the out of phase trick up until say the first audible peace of audio (or say a snippet between 2 "hits" or impacts) then it does you no good... (and really you can just remove the audio anyway if there is no source sound in it) You could record the room before you record with the fans going though and try to use that to throw only the fan sounds out a bit... but that gets tricky with fan RPM changing so the sounds arent going to be an exact match, it could help with some of the noise reduction though.

Best bet, as I stated, is to record away from the computer or use baffling to isolate the source from the room.

[PeterGreen]

Originally Posted by hjorte

There is no way a laptop cooler will be able to cool a PC laptop to the extent that the laptop won't need to switch on its internal fans at some point when doing even low to average CPU/GPU extensive tasks. Disabling the laptop fans (if at all possible) is not recommended.

A laptop cooler is not comparable to and nor is it a replacement for laptop internal fans.

Oh there's no way I'll switch off the fans, i don't even think it's possible. However the processor temp triggers the fans so how about using a block of ice spreading cold air underneath. If that keeps the processor cool for longer time than the fans won't get triggered so often. Could keeping ice close to my laptop damage any parts or interfere with the working because of too much cold? Or is it just a crazy idea?