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Port noise (1 Viewer)

Frank Kanyak

Stunt Coordinator
Joined
Feb 28, 2002
Messages
240
Is there any solution to control my port noise at during some intense scenes. I did do a search in the DIY to no avail. It sounds like a chuffing like someelse said. ^' port x 26" length.
 

Chris Tsutsui

Screenwriter
Joined
Feb 1, 2002
Messages
1,865
26" is pretty long, is there a shorter length alternative?

Are your ports flared? I found that my two 11" flared ports create no noticeable air noise. (Unless I run a test tone and listen close to the ports)
 

Greg Monfort

Supporting Actor
Joined
May 30, 2000
Messages
884
You can stretch grill cloth (or similar) over the vent, turning it towards Aperiodic. Peak vent output will drop a little. If one layer isn't enough, then try two, but the main thing is getting it tight. Once you have the right amount, make a frame to attach it to, and to the sub.

BTW, this improves transient response too, though how audible it will be I can't say.

GM
 

Ron Shaw

Stunt Coordinator
Joined
Dec 4, 2001
Messages
142
Port noise is caused by the port area being too small. The velocity in the port should be kept below Mach .2 in order for port noise to be inaudible. Increase the area (diameter) of your port. You will need to increase its length to keep the tuning the same.
 

Dave Poehlman

Senior HTF Member
Joined
Mar 8, 2000
Messages
3,813
Is it a DIY sub, Frank?

Flaring the port may help. Widening or doubling your port will definately help. As stated above.. you would have to rethink the length of your port(s) if you want to keep the same tuning.

If it is a DIY sub and you are using PVC pipe.. make sure the ends are cut smooth.. sometime a burr or rough cut can cause noise.
 

Greg Monfort

Supporting Actor
Joined
May 30, 2000
Messages
884
Well, you can stick a longer 6" tube in, but it'll probably need to be ~45" long to be effective, or you can double up or stick a larger one in, which will make it (them) even longer. Not good plans IMO, so this leaves either my suggestion, a combination of my suggestion and make it a little longer, or seal it up.

GM
 

Greg Monfort

Supporting Actor
Joined
May 30, 2000
Messages
884
Just the opposite unless you accept the higher distortion of increased excursion, though frankly it will be low enough in frequency that overall it may sound better.

GM
 

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