I'm X-static for Voce

Posted by: Steven Stone at 11:11 am, April 30th, 2009

 X-static for Voce
 
 I’ve been a fan of the AV123 X-static speaker since I heard the prototypes at the 2008 Rocky Mountain Audio Fest show. Additional listening at the 2009 RMAF and Wayne Garcia’s glowing review in TAS 189 did nothing to dim my ardor for this speaker. When I saw an ad in Denver’s Craig’s List posted by AV123’s Mark Shifter for an open-box local pick-up only pair of B-stock X-statics for $350 I jumped on them. I also bought a B/C-stock Voce center channel speaker for $150.
 
 
They were B-stock because one of the two X-Statics had a slightly crooked front speaker grill and the Voce had extensive finish flaws on the rear. These speakers are a great value at their A-stock price of $990 per pair for X-Statics and $499 for the Voce (plus shipping,) but the B-stocks were no-brainer must-buys at the listed prices in the Craig’s List ad.
 
Why, with a complete Genesis 6.1 surround system supplemented by two Genesis 2/12 subs and two JL 112 subwoofers, would I want to own the AV123 X-Static system? Simple – the Genesis servo amplifiers that drive the woofer and subwoofer modules in the 6.1 front speakers and subwoofers don’t like Rocky Mountain power outages. During the five years I’ve owned the Genesis system I’ve had to repair every single servo amplifier at least once, usually in the spring after a couple of big energy-killing storms. It takes at least a month to get back the repaired modules. Now I have something to listen to while the Genesis amps are being fixed. 
 
 

 
 

 
X-Static Modifications
 

Although the stock X-static and Voce speakers are fine performers, some easy modifications that virtually anyone can perform will make them sound even better. First, you must remove (and store) all the metal grills. If you tap them even lightly they go “sproooooong.” The last thing you need is a grill that adds midrange resonances, so they MUST go.
 
The next modification is almost as simple. It involves two kinds of felt damping. Before I explain the how, let me explain the why. Upon initial examination the X-static and Voce might look like quasi-bipolar designs which generate energy both to the front and rear due to their lack of a cabinet. But actually these speakers aren’t bi-poles, but open baffle designs with a conventional D’Appolito array. The lack of a cabinet box around the tweeter and midrange drivers vastly reduces cabinet resonances.
 
If you listen to the sound coming from the rear of the speaker it is comprised of primarily midrange energy since the midrange driver isn’t sealed. Because there is no rear-firing tweeter as with the true quasi-bi-polar Genesis design, and the X-Static’s tweeter back is sealed, there’s no high frequency energy leaking out the back of the speaker.
 
The extra midrange energy coming out the back of the X-Static doesn’t help generate a larger soundstage, but merely reduces the speaker’s midrange definition by time-smearing the midrange with out-of phase information. The X-Static’s low-level detail can be significantly improved by damping the energy coming off the back of the speaker. The trick is to do this with absorptive material that will not add any resonances of its own or redirect out of phase midrange energy back toward the front of the speaker. Industrial-grade felt is the ideal material for this purpose.
 
I used two different types of felt to damp the midrange driver. The first kind of felt material can be found at most large hardware stores in the window/door weatherproofing department. It’s ¼” thick felt that’s 1” wide rolls for filling gaps in windows and doors. I wrapped this felt around the circumference of the X-Static’s midrange drivers, building up a layer about 1” thick. This absorbs some of the energy coming off the back of the midrange driver cones.
 
The second type of felt I used was ¾” thick industrial felt that I got through the Internet. I use this same material to cover my computer desktop. It comes in sheets of various sizes from which I cut small rectangles which I glued with heavy-duty rubber cement to the back of each midrange driver. It damps the metal backs of these drivers, which go “ting” if you tap them lightly. This is a midrange resonance that becomes a problem only at higher volume levels. My pictures of these two mods should clarify how they were installed.
 
The goal of these felt mods is to absorb as much rear-firing midrange energy as possible without adding any physical resistance to the back-wave to the midrange drivers. I wanted to attenuate the out-of-phase midrange while not impeding airflow from the drivers.
 
Doing the felt mod and removing the speaker grills increases the X-static’s ability to play at higher SPL’s without getting muddy. Combined with crossing over the speakers at 80 Hz into subwoofers, the X-statics go from being very good to jaw-droppingly amazing. They gain greater dynamic capability as well as increased low-level detail and soundstaging accuracy. 
 
One final tweak for the X-Static and Voce involves a Torx screwdriver. TIghten all the Torx screws on the drivers. Be careful, if you over tighten you can easily strip the screws in the wood. About 1/8 turn was all I did on most, but a couple were rather loose and needed 1/2 to 3/4 turn.
 
 
 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Voce Voicing