Subwoofer Tunes

[Auricauricle]

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]

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.

[BallinWithNash]

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.

[paulspencer]

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.