Anyone who's tuned their 20-39pc+, gotta question... (1 Viewer)

[JohnTKline]

If you've tuned it down to 16Hz with the port blocker, have you noticed any difference in losing any power at your listening levels? Or was it insignificant compared to the lower bass response. I hope I worded that correctly...

John

 

[Chris Tsutsui]

I don't have SVS but in my experience with tuning a tempest: Lower tuning meant the bass was able to hit slightly deeper but it's not as easy to hear. When the box is tuned higher, it produces a more noticeable amount of mid bass and loses some of the deep stuff.

If deep bass isn't missed in most of the stuff you listen to and you like slam for HT then I'd use the higher tuning. It gives your bass some headroom and allows for some higher SPL at the sacrifice of deeper bass.

 

[Mark Kreisberg]

I did not notice a difference with one port plugged. I did, however, when I plugged both ports. My 20-39PC+ is currently tuned to 16Hz.

 

[Edward J M]

I can immediately notice when one port is plugged and my B&K SPL meter confirms it - SPL drops about 1-2 dB when a port is plugged. This is expected, of course, in exchange for a lower tuning point. Recalibration is in order after a port plug is used.

Interestingly enough, I found simply dropping the SS filter to 16 Hz and leaving all three ports open actually increased SPL when the Ring drops to the ground in the opening scene of LOTR-FOTR. That passage must contain significant SS content.

A typical HT room gives some extension and reinforcement - maybe another 3-4 Hz. I've been wondering if it might be beneficial to run all three ports open and have the SS filter set to 16 Hz to take advantage of typical room extension.

What do you guys think?

Ed

 

[Robb Roy]

I have recalibrated after each tuning, and my 20-39PC+ has been able to fill my 20x20 HT area at each point with no problem. If there is a difference after calibration, I haven't been able to notice it yet (I'm still experimenting).

-Robb

 

[Yee-Ming]

I found simply dropping the SS filter to 16 Hz and leaving all three ports open actually increased SPL when the Ring drops to the ground in the opening scene of LOTR-FOTR. That passage must contain significant SS content.

interesting observation. I tried this scene a few days ago as a demo, but thought that the bass wasn't particularly fearsome, as contrasted to scenes like Bridge at Khaza-dum (sp?). but I have an SVS25-31PCi tuned to 22. if the bass on this is really infrasonic, that would explain it -- my little SVS doesn't go that low :frowning:

 

[Edward J M]

A typical HT room gives some extension and reinforcement - maybe another 3-4 Hz. I've been wondering if it might be beneficial to run all three ports open and have the SS filter set to 16 Hz to take advantage of typical room extension.

Update: I asked Tom V this question via email. In typical fashion he responded almost immediately.
He says running all three ports open and setting the SS filter below the natural tuning point of the enclosure leaves the driver vulnerable to sudden subsonic spikes that could damage it - IF the sub is run at very high levels. At lower levels this practice is OK, but caution is the word of the day.
I like to crank my 20-39PC+ pretty high sometimes, so I think I'll leave my SS filter set at 20 Hz with all three ports open.
Ed