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Need help with Kinergetics Subs - Newbie

Total newbie question here...

Denon 2805 receiver
Spica TC-50 mains
Kinergetics SW-200 subs
Jamo S3 surround

I have a pair of Kinergetics SW-200 subs that have a problem that I need help troubleshooting. If you're not familiar with these older subs, they are a left and right sub each with two 10" cone speakers. Since my Denon 2805 only has one sub pre-amp out, I split this signal and feed to the L/R channels on the Kinergetics amp.

The problem is when the bass gets to a moderate level, the right sub box (again with two 10" speakers in it) starts to make a loud jackhammering staticy type sound. One of those wrong sounds that makes you run to turn down the volume before your system blows up. Both of the speakers in the right box seem to break down at the same time, so I'm not sure if it the speaker cones / coils or something with the electronics in the box. I usually blow a fuse soon after, too.

I don't see any visible cone damage and the subs sound fine at lower volume levels.

The left speaker box will make the same sound but only at a much higher level. The right speaker box definitely has the problem long before the left does. Am I just pushing the subs too hard for home theatre? They seem to be made to be a very subtle sub.

Anyone familiar with Kinergetic Subs? Are they right for home theatre or am I just trying to do something they weren't made for? I always thought "a sub is a sub" and can be used for multiple applcations, but maybe these aren't cut out for HT.

Anyone have ideas of what the problem is?

Thanks for any ideas / help!

John
robotman
rpw
47 posts
 
John,
I have owned the Kinergetics SW-200 for about 12 years now and have had the problem you are referring to. The amp section is the culprit, it is a 150 wpc unit using inexpensive bipolar transisters that clip very easily. The left and right sensitivity knobs are not matched evenly, that is why you are getting more clipping in the right channel. These subs are for two channel music and not HT, you can use them for HT, but don't expect miracles.

I use an outboard amp full range with 95db at 20 hz and no clipping which is quite loud in my 22 x 13 foot room.
I do not use the crossover to the main speakers but run the subs full range up to the 100hz crossover point. I also use my main speakers full range, more transparent sounding. Follow the directions for outboard amp use and try a good sub amp with good current and you should not get any clipping. I use an ATI 1502 ss amp and measure output with a Radio Shack meter and test disc. You might want to try it both ways and see which you prefer, the Spicas don't go very low and might benefit from using the crossover. Either way a decent outboard amp is a must with this system to get the most out of it. Good luck.

Rich
robotman OP
35 posts
 
I have switched the amp out wiring and the problem follows the cabinet. I actually had an offer for a good deal on a replacement amp, but unfortunately it seems to be more in the cabinet.

I don't know how to further troubleshoot the cabinet.

It's very hard describing the noise... it reminds me of that weird loud deep staticy (yet oddly quiet) sound that accompanies a nuclear explosion in a movie. Just as the mushroom cloud is forming and everything is getting blown away.

Based on that fascinating description, can anyone suggest some things to test or possible causes? Something is getting overloaded (possibly because it is already weakened).

Thanks for your help!

John
robotman OP
35 posts
 
Just to clarify... it's like the sound when nuclear explosions are showed in very slow motion and everything is getting blown away in slow motion (if that helps). Nuclear crackle...
robotman OP
35 posts
 
Rich - Thanks for all the very useful information!

The only thing that doesn't jive is that when I switch the L/R wiring, the R cabinet still clips first even being hooked up to the L outputs.

Again... I'm a total newbie with audio equipment. Is an "outboard amp" just a normal amp (like the Kinergetics amp minus the crossover function)?

Currently I'm feeding 80Hz and below to the input on the Kinergetic amp and then just outputting it to the speakers. I'm not using the Kinergetics crossover right now, just the Denon's built-in crossover.

It would be great if just another amp would improve the problem.

John
rpw
47 posts
 
John,

Yes, an outboard amp in relation to the Kinergetics amp/crossover unit is just a normal amp, preferrably one with high current for good bass control. The description you give does not sound like clipping, the sound I hear when the speakers clip sounds more like a metallic popping sound. I wish I could help you out but I'm stumped. The crackle static sound seems more electronic to me. Don't forget your summing the output from the receiver so the left and right should be the same. Try lowering the sensitivity knobs to about the 12 o'clock position then raise slowly. I have never had the knobs much past the 2 o'clock position, too much bass and they distort easily.

Rich
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