[rjmaurer]

If had a VMPS original subwoofer for years. It hasn't been used in about 10 and I'm trying to incorporate it into a home theater remodel. I found the passive radiator's surround had deteriorated so I replaced it with a Dayton Audio SD315-PR 12" passive radiator. I bypassed the crossover, wiring the leads to the driver directly to the posts in the back of the speaker. I am driving this with a AudioSource AMP 1 bridged for mono which should put out about 200 watts. The receiver is a new Denon 3313 and the front channels are old Polk Audio Monitor 10s and the center and rear channels are new in-ceiling 70-RTs. So here is the issue .. I'm just not impressed with bass. Low end seems weak. Not sure if I should replace the woofer with a better/newer one (I see a lot of talk about 'mega woofers' so it seems main VMPS owners have swapped out their drivers), get a more powerful amp, or toss it out and use a new powered sub or two. So is it worth it to do more with this thing? So far the passive radiator fix was only $40 and I had purchased the amp some years ago so I'm not out much if I toss this and replace it with something modern. Any advice would be appreciated.

[ST86]

First thing I would check is weather or not the bass management settings on your Denon are correct (speakers set to "small" to route low end to sub?) if you have a variable subwoofer crossover setting what that is set to (typical is 80 Hz).

Ed

[Stimpy]

VMPS subs were designed to be 'tuned' to the room, and the driving amp, via 'pinching putty' on the passive radiator.  With the original passive, replaced by the Dayton passive, there's no way of knowing how the sub is responding to the passive radiator change, with the sub no longer being properly tuned.  Though, it sounds if the sub may be over-damped, since bass "seems weak".  After trying ST86's suggestion, of veryifying the receiver set-up, you might pull the passive out of the cabinet, and try adding a small amount of weight to the passive radiator.  If there's a threaded screw on the back of the passive, try adding a washer, reinstall, and listen for bass changes.  If the washer helps, add additional washers, one at a time, until you reach the bass sound quality, that you like.

Also, since it's a new passive, it's surround my need a fews days of playback, to loosen it up?!?  Maybe adjust via adding washers, after break-in...

[rjmaurer]

Thanks for the feedback! As for the Denon - done that. One of the first things I did was set the front channels to 'Small' and adjusted the crossover. As for the damping - haven't tried that yet simply because it is such a pain. You are right about the screw where washers can be added but it requires the removal of the base and the passive to get to it. A greater break in period may be needed. The room it is in is undergoing a 'back to the studs' remodel so it has only been used for a few hours. Watched a few movies using the new hardware making sure all is ok before the walls are closed up. I guess I shouldn't be too critical until after the drywall and carpet is back in. After that I'll do the tuning and see. Also the Denon setup has been rather basic - one sitting position measured - since this is temporary until the room is done.