The Kavernas MTM HT Mains
  • Peerless HDS Nomex 832873 5.25" Midwoofer
  • Beston RT002A Ribbon Tweeter
  • 13 liters net volume
  • 1/2" Baltic Birch through out
  • 2" Diam X 4" Port, F3 63Hz (estimated)
  • 88 dB estimated sensitivity

I wound up with a bunch of these little Peerless mids at the last PE "buyout" sale. I figured if they were good enough for the Linkwitz Pluto they would be just fine. I really like planars & ribbons so I decided I'd give these new Beston's a try. I thought they'd look sexy with the truncated Peerless. Besides, if I didn't like them, I knew I could drop a Neo3PDR in that space. These needed to be a bit on the petite side, but I wanted the vertical "control" of an MTM.

With a sub and an honest 30 watts from my HK 154 receiver, I undersized the box to help control cone movement and give me some flexibility in crossing to the sub. This 13 liter configuration gives a shallower, gentler rolloff that should make it easier to match up with a ported sub. FOR MEASUREMENTS CLICK HERE

I was a bit concerned about the low end reach of the Beston. I tried the smaller RT001 in an unpublished 3 way. The smaller one dropped like a rock at about 3500 but I liked what I heard. So I set up my gear to emulate the conditions that would be close to their intended application sitting on a table 3 feet off the ground. Planars present some issues with respect to accoustic centers. Since it's not a point source, there's not really a measurable "center". I found that setting up farther away makes that a bit less problematic for simulation. The RT002 looked like it would be doable down to 2500.

After three design cycles, I settled on the crossover shown below. The peaky artifacts up in the 15000 range are inaudible and may be due to my new measurement setup. I set up a notch filter to get rid of it, and it's just not audible. Pretty simple really. Coil/Cap for the Peerless, third order for the Beston. Final crossover is at about 2800. I liked a 4.7 ohm padding resistor in my prototype, but I will hold off on final voicing until I have them in place. I think these would be very nice for standalone use with moderate power. There isn't a ton of bottom end, but what's there is very clean and punchy. Good bedroom system or for the executive suite as stand alone boxes.

Nov 12 Update

Got these set up with the HK 154 & rolled them off at 80 hz with bass management. I thought they were a bit dark & polite with the garage gear. The HK exaggerated that condition. I swapped out the 4.7 for 4 ohm padding resistor and these babies positively glimmer. Relieved of the absolute low end, the soundstage is wide open, bright, and even a bit forward. With the Bestons, (like the NEO3) I like running these a little bit hotter than most domes. I'll trade a bit of bad-mastering rasp for the top end sparkle in these. High sensitivity - I couldn't sit in the room with the full HK 30 watts running through them. A little bit of padding change makes a world of difference. I'll now move these Bestons up to NEO3 league and would gladly take them over the HiVi planars. A bit less off axis dispersion than some domes, but nothing I found objectionable. Nice integration with the center channel, and tolerable on TV commercials and other nasty sources. For music, I will be very happy to spend some critical listening hours with the Kaverna's (and a sub).

Dec 5 Geek Fest

After hearing the Kavernas, next to the TunDars and other boxes. A few folks thought the Kavernas were a bit forward in a bright large room with my digital Panny receiver. But on stands, out in the room, they were exceptionally sweet with two different tube setups. Most found the bass to be decent for the size of the box. Everybody liked the Beston ribbon (at least that's what I was told). Part of the "forward" sound comes from going light on baffle step.



Measured at 1.5 meters, 36" ground to box bottom. Lots of ground bounce.