Do Plugged Virgos sound better?


I recently set up a pair of Audio Physic Virgo IIs and was having a hard time controlling a mid-bass hump. At first I used them on the carpet without their spikes, but when I spiked them to the floor the sound (and the bass) did not change all that much. I tried some other measures, messed with positioning and subwoofer settings on my Servo-15, etc., but still could not entirely rid myself of that boom. Then, on a whim, I plugged the bass ports with some rolled up foam. That actually seemed to help reduce the mid-bass boom and tighten them up a bit. Now the bass is pretty respectable (has good articulation and solidity) over a wide range of recordings. So for me, plugging the Virgo's ports worked well in my room. Have others done this, and if so, how do your results compare?

I used to have a set of B&W CDM 9NTs that came with foam port plugs for exactly that purpose, so that's probably why I thought of it.
plato
I've measured the 1/3 octave response of my room both ways, and plugging the ports definitely reduces interference between the mains and sub where they overlap.
I found this to be especially true if the mains are running fullrange(not high-passed).

The downside is that the deep bass power handling of your woofers may be reduced slightly, due to a reduction in port damping at resonance.

BTW, maybe we can measure the response at your listening position later this week.
Hi Snickelfritz; what you said makes sense because if I run the Virgos without the sub the midbass hump is not nearly as prominent (presently I'm running the Virgos full-range). With the sub, no matter how low I cross it, it seems to increase the midbass too much.

And sure, if you have an accurate "kit" to measure the bass response, maybe we can chart the response and possibly fine-tune it a bit further. That would be great. Thanks!
I have a simple Ratshack SPL meter/tripod and Stereophile TestCD with 1/3 octave warble tones, and a rough correction curve for the microphone response.
(close enough for this purpose)

BTW, this greatly helps in finding the optimum setting for the X-30 variable phase control.
It's interesting to watch the cancellation frequencies slide up or down the spectrum as the control is rotated.
Differences of 10 degrees rotation can be very significant at some frequencies.

Also, moving the main speakers by as little as an inch or two can make a large difference in the upperbass balance and smoothness.
I was able to get ruler flat response(+/-0db) from 200hz down to 80hz simply by moving the main speakers a specific distance from the front wall.(37" in my case)
Other positions resulted in windows as large as 6db in this range!
The difference this makes in overall bass transparency can't be overstated, especially if the low-midbass maximum is reasonably close to the reference level.(difficult compromise between extension and room-boom)

I'll be installing a set of lowbass, midbass and midrange traps this weekend. If the measurements are promising, maybe we can construct some for your room.
(the 2'x8'x4" paneltraps cost about $35 each to build)
Technically, anything that has been plugged can no longer be considered a Virgo ;>)
I've tried some of the old-style, round Room Tunes, but not actual bass traps. But I may try bass traps in the near future if my latest efforts fall short of my expectations...
Also, do you follow the immedia speaker positioning. When I had virgo's this worked wonders...

http://www.audiophysic.de/info/aufstellung/e_index.html
Elgordo, it is true that once plugged, they are no longer "Virgos" but I kind of dig their new sexy "navels".

Jfrech, I've seen Audio Physic's recommended positioning rules but in my room they are not that practical as I will have to move the speakers a lot farther into the room than I would like or would be convenient or aesthetically pleasing. Everything but the bass is spot-on, so once I refine that, maybe with tube traps as Snickelfritz suggested, all will be bliss...