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RE: Some comments from a long-time owner.

Posted by corerosin (A) on November 27, 2007 at 21:32:41

In Reply to: RE: Some comments from a long-time owner. posted by jsm on November 27, 2007 at 17:10:55:

I didn't mean to dump on you about this. It's just that the 105's were the only world class speaker system I have ever seen that had a high pass filter into the woofer. When I saw that the first time I couldn't believe it. I figured it had something to do with making all the drivers operate in a bandpass filter to control phase. However, if you run the numbers assuming that the composite series cap is half of a 12db high pass filter into an 8 ohm load, then the -3db point is at 39hz. Below that it will roll off electrically at -12db and ostensibly another -12db for an acoustical rolloff. Sort of a brick wall at 40hz. Now that's okay if you're running records and want to minimize the chance of turntable rumble, but in a digital age, that seems meager to me. And when you run into speakers that are cutoff in that way, you wind up hearing comments about how much better the speaker sounds once you put 200 watts into it. Well, power won't actually change anything in this case.

That's too bad, because apart from the limitations in the extreme bass, the 105 is a stellar performer. I love the performance of that oversized tweeter. I would guess the wonderful frequency response is a consequence of the fact that though the tweeter is a dome, it isn't really a hemispherical dome. It's tremendously flattened out which extends the flat response and broadens the operating surface, or to put it a different way, the tweeter doesn't stick out very far from the surface of the baffle. That's a really good idea. The output at the center of the dome isn't fighting the output at the edge. -

Anyway, I have had friends who have owned 105's and both of them had to have their woofers replaced. A rather expensive proposition. Both of them attempted to 'fix' the bass problem by using bigger amps. It doesn't work. It just burns up the woofers.

I was just wondering whether anyone simply bypassed that high pass filter. It would be a gutsy thing to do. Simply bypass the three 120uf caps and disconnect the parallel coil and reverse the leads for the woofers. That should put the woofer in correct phase again. You might try it sometime. I don't know what it will do. Maybe nothing. Probably it will just soften the brickwall at 40 hz.

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