SVS tuning? (1 Viewer)

[timZa]

Just wondering where most of you have your Ultra or Plus2 tuned. also does it matter which port is plugged for 20hz, the top or bottom? i gave the 20hz a try but did not stick the plug all the way down in the port. now looking at the manuel it says to drive it in the port about 1 inch from being flush. when i did the 20hz i had it sticking out several inches, would that make much difference?

 

[Kevin C Brown]

I use the 16 Hz tune. I don't play movies all that loudly, but I want the deepest extension I can get.

 

[Arthur S]

My recollection is that Ed Mullen, noted sub reviewer, with tons of experience with many SVS models, after much experimentation, concluded that the 16Hz tune is optimum.

 

[RichardH]

Also just to note, the dual driver models are 16/20/25 Hz selectable, whereas the single driver models are 12/16/20 Hz selectable. I've read that if you go down to only 1 port open, it's underported. So I think 16Hz is the optimum only if you have a single driver SVS. Corrections or additions, anyone?

 

[Arthur S]

I am thinking the SVS 16-46 PC-Plus is 12/16/20 selectable.

 

[Edward J M]

"Optimum" is really a function of the particular application.

If you have a very large room and you want maximum slam and headroom at high playback levels, the go with the 25 Hz tune. You'll have strong extension to about 21-22 Hz in-room before roll-off.

The best combination of extension and output is the 20 Hz tune, giving up about 2.0-2.5 dB in headroom (compared to the 25 Hz tune), but gaining extension to about 17-18 Hz.

The 16 Hz tune has the least headroom (giving up about 5-6 dB over the 25 Hz tune), but will extend in-room to 13-14 Hz. In mid-size rooms where extremely high playback level is not the first priority, it can be a good choice.

I run dual Ultra/2 in a mid-size room, so headroom is not an issue and I can afford to run the 16 Hz tune without encountering compression or audible artifacts. And the 16 Hz tune is somewhat overdamped (anechoic), so when combined with room gain the resulting in-room response tends to be flat down deep (instead of rising as might the 25 Hz tune). So for my particular set-up and application, the 16 Hz tune is "optimal", but it may not be for everyone.

 

[steve nn]

Yes indeed..there are those that even opt for a 14.25 Hz tune. There are some pretty goofy bass-heads running around.

 

[Kevin C Brown]

Hee, hee. I have a single Ultra/2. I have plotted the freq response in my room down to 11 Hz. And actually, I get pretty flat response from 11 to about 40 Hz (well, as accurate as the Radio Shack meter with the cal factors can be). Above 40 Hz, room nodes take over. Someday I'll try 2 Ultras. (I came close to pulling the trigger in July, but I'm still holding off). Not for more output, but flatter response across the room.



This is un-eq'ed. Someday I'll do another graph with the auto eq setup I now have in my system.

 

[Edward J M]

Dual Ultra/2 about 3 feet apart on the front stage (flanking the equipment rack but still between the mains) killed a 40 Hz null in my system. With bass trapping and a PEQ to kill a 70 Hz floor/ceiling peak, the response is quite flat from 12-100 Hz, including the mains (using a 100 Hz electronic XO with is actually about 90 Hz acoustic).

It took a lot of tweaking with the subwoofer distance and different XO points while measuring the E/T curves and phase response curves of the LCR speakers and the subwoofer, but it was worth it. You don't even realize there are subwoofers playing in the system when listening to music.

 

[Arthur S]

Ed, thanks for clarifying my generalization. For some reason, I'm thinking you are working on an IB, did I just dream that?

 

[Edward J M]

Sure thing Artie.

Yes, an IB is in the works, but I don't have the time to devote to it right now.

 

[Seth=L]

I would like to think plugging the top would be the best option since most subs that have just one reflex port have them positioned lower on the cabinet. Also about the plug being in a certain distance, I don't think it would make much difference so long as it is completely closed with no air leak. I used to have a Paradigm PS-1000 which was a bandpass enclosure with three large reflex ports on the rear. I used cloth to plug the ports and it sounded fine. Without at least one port plugged the subwoofer was a chud machine. It actually sounded nice after I plugged some ports.

 

[timZa]

Seth, thanks for clarifying the question.

 

[Kevin C Brown]

To be honest, this is another thing holding me up. To do multiple subs correctly, takes a lot of work. I need to make sure that if I get 2, that I can do them justice.