Subwoofer Tunes [Archive] - Audio & Video Forums


View Full Version : Subwoofer Tunes

01-29-2010, 10:32 AM
At the time of this writing, I listen to a 2.1 set-up, including Polk Monitor 7c's as mains and an Eosone RSP 912 sub-woofer. All in all, it's a very engaging set-up and I have enjoyed beautiful music through them. Recently, I realized that the sound coming from the sub was a tad off. The sound is there, but reproduced in a somewhat hollow, rather round sound that doesn't sound at all musical. Then I remembered a trick I've known drummers to use: stuffing cloth into their bass drums...With this in mind, I took an old tee-shirt and stuffed it into the port. Voila! The bass has gotten noticeably tighter and that hollow ring is just about settled.

This morning, I spoke to a friend who is familiar with sound about this situation. He suggested purchasing a bag of cotton balls and putting those into the port, opining that their quality would be more beneficial. Well, I have done so, and thus far I am quite happy with what I am hearing. Presently, I am listening to Paris album, by Supertramp. The bass is tight and quite clean. Drums have that familiar, wonderful snap; bass guitar is resonant and articulate.

So, hear's (!) the question, all....In fine-tuning a sub-woofer, are such measures necessary? Should ports be left alone? What other tweaks can be employed to derive more satisfaction from subs?

Come on, now....Enquiring minds want to know!

JoeE SP9
01-30-2010, 02:57 PM
It depends. If it works for you that's your answer. Hsu Research talks about stuffing the ports on their subs for better sound with music. IE: Lower and smoother. Un-stuffed you apparently get more absolute volume.

01-30-2010, 11:47 PM
Try putting more insulation or foam inside the cabinet, I made my own cabinet and used foam I believe it was 1/2 inch thick I applied it to all sides except the side of the speaker and it sounded hollow so I doubled a couple of the sides and that worked for me.

02-22-2010, 01:12 AM
There are a few things going on at the same time, and from a distance it's not easy to say for sure exactly what you are hearing. What you have done is create an aperiodic box, which is essentially a leaky sealed box. Sometimes this is done deliberately to allow a smaller volume than a sealed box. You've given up a fair amount of output and extension, and it's possible that the tigher sound could be related to the room rather than the sub. If you have a peak in output around vent tuning (quite common), then plugging the vent will cause the bass to roll off sooner. Now instead of a big peak the bass is smoother. If the vent is poorly designed then plugging it might hide the issue. If the room is the problem then a better solution is EQ and measurements - you get tighter bass without giving up output. If the problem is with the port itself, then a better solution is converting it to sealed. What you want is a small panel attached over the port with a rubber seal and screws to fix the panel.