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My experience adding subwoofers to 2 channel

My Kappa 9 speakers are rated to 29hz and they sound pretty good in my 18x24 room...powered by McIntosh mc1.25 amps...l was looking for another layer of bass to enhance the sound..my first experiment l took my SVS pb16 ultras from my theater room and tried them first...it sounded terrible,didn't blend well..couldn't hear a difference until you turned in up then it rattled the room apart........my final experiment worked..l used 4 Velodyne minivee subwoofers(1000 watt rms class D sealed 8 in.) and after hours of calibration l hit it......lve got the bass response that exeeded my expectations. ....l should have done this along time ago....can anybody tell me of another subwoofer that may work even better?
vinnydabully

Showing 2 responses by atmasphere

atmasphere's avatar
atmasphere
12,116 posts
 
@mijostyn I've heard the direct drive version- that speaker never seemed to bring home the bacon the way the one did that was easily driven by the M-60s (which replaced an ARC Classic 60; this was a good 15 years ago).
I wish I knew which model that was as I've heard Acoustats that looked just like it but needed a big amp to make them play. The first time I heard an Acoustat though I was very surprised at how well our amps and the speakers worked together. IMO they worked quite a bit better than the Quads, which at the time were also easy to drive.

By comparison the direct drive model had a bit of a trashy sound on top and we got better bass with the regular speaker (it had no hint of trashiness!). But I think there was a good possibility the power tubes in the direct drive model I heard were simply shot. That was a tricky speaker- you really had to be careful around it due to the very high plate voltage on the power tubes.

Of course I've heard Sound Labs many times. Something like 80% of all our MA-2 amplifier production has gone to Sound Lab owners.
atmasphere's avatar
atmasphere
12,116 posts
 
I wouldn’t even consider a tube amp to power subs due to their generally low damping factors and their resulting poor ability to firmly control the movement of dynamic cone drivers, especially the precise starting and stopping required of larger and heavier bass drivers in subs.
Actually this 'precise starting and stopping required of larger and heavier bass drivers' is a bit of a myth. You can get excellent and natural bass out of a tube amplifier if you set things up right. Our amps go full power to 2Hz so no measurable square wave tilt at 20Hz. So often what causes people to think tube amps don't make good bass is phase shift; if there is a cutoff within 1/10th the lowest frequency to be amplified phase shift will be present. This can cause a lack of impact. FWIW, if you overdamp the speaker it will be less able to play bass impact correctly; no speaker needs more than 20:1 damping factor.@mijostyn  Some of those Acoustats were very easy to drive and some weren't. I've never figured out the models, but a customer had a set of M-60s driving Acoustats and the combo was wonderful. The Acoustat was a very nice and IMO an undersung product.

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