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I too, like Blvdre, use a passive preamp & I have found it to be superior to both an Audio Research pre & a Naim pre, both of which cost considerably more. The passive produces no extraneous noise at all & is wonderfully open & clean.

I too run a passive preamp (purely for gain control & source selection) & I find the sound much cleaner & purer than with an active preamp. Everyone says you won't get the same bass control with a passive or with no preamp, but then they hear my system & they can't quite believe it. To be fair, it may be system dependent & I've only ever had highly efficient speakers, so that may count for something.

That is a pretty bold statement. If this is really doing that much for bass extension, than you definitely have my attention. Can we get any numbers to back up the subjective observations? Daniel I have a test disc (original Master Recording - "Sound Check by Alan Parsons & Stephen Court) that has amongst other things 1/3 Octave test bands. When the speakers were firing into the room I could just hear the 50Hz tone. Now that they are firing into the rear wall I can just hear the 31.5 Hz test tone & the 50 Hz test tone is much stronger. Without any dedicated testing equipment that's the best I can do. I tend to agree with Greg though that if a trace was done it might not look all that great, but the proof is in the pudding!

That is a pretty bold statement. If this is really doing that much for bass extension, than you definitely have my attention. Can we get any numbers to back up the subjective observations? Daniel Daniel, I was quoting Greg there re the KHorns...but I can tell you that they are as deep as my Altec Model 19's, which go comfortably to 30Hz. I don't have any equipment to run any figures but I agree it would be cool to see exactly what is happening here.

Here's a rough plan of the positioning I have at the moment

"The bass was as deep as my Khorns and even tighter. It was really amazing. I'm still shaking my head over it. I was playing Spyro Gyra "Original Cinema" and I just couldn't stop listening. I just let the whole CD play. There were a few moments that made me sit up and say holy sh*t, what was that! I can't wait to go back tomorrow and crank some more tunes." Greg, Read through that thread & a couple of comments from a few questions that were raised. Yes, the bass is even tighter than before & as you say, stronger in the mid bass & certainly subjectively lower in frequency. It has a wonderful tactile sound to it...you can feel the texture of the strings. This just doesn't sound like LS bass! I can't detect that I am losing any upper or mid bass even though this bass cab would go slightly beyond 400Hz. I agree it's probably not for every room but it certainly works in mine. One thing - at very high levels it can tend to overload the room with bottom end. Will have to do a bit more experimenting with positioning.

Has anyone ever tried turning the bass bin of their La Scala 2's back towards the wall? Since getting my LS2's up & runnning, the bass has always been, well, not quite right. Sort of in the back of the mix a bit & not as easy to pick out as I'm used to. So I tried turning just the bass bin to fire into the back wall & the corners & wow! Not like I remember at all when I tried this many years ago...maybe a room acoustic thing & it may suit my new room. The bass has come alive & is instantly discernable, the tone is spot on with more timbre & texture....the growl has returned. Much smoother & warmer too. I would have thought that the imaging would be inferior, but no, sounds OK to me. All in all a huge fix. I highly recommend you try this because I thought it would never work but was proven wrong. If anyone can do this & provide any measurements to see what we are actually hearing, that would prove very interesting.

and doing the knuckle rap test on the finished article.

And the finished article.

Make one template & cut the others from that.

Decided to try some dampening material on the K400's. A friend had some sound deadening material primarily for automotive applications. It's a combination of thermal reflective & butyl rubber with self adhesive. Impressions are positive with a slight softening of the mids which are now slightly more recessed in the sound stage. This has subjectively improved the bottom end making it easier to follow the bass line. Very easy to apply....just cut to size with scissors...remove backing paper....and apply. Even easier when you have your friend do it for you....thanks Sandro. A worthwhile & low cost improvement! I love that.

Greg & Co, Thought you may be interested to read this info on some early tractrix designs for bass horns. spexemplar.pdf

Now THAT is a compliment from the best. Yes, very nice work, handsome grain pattern. Michael Yeah, I appreciate your comments Greg & don't forget that you gave us the inspiration to use this design. Another comment on the sound quality as I've done some more critical listening. I believe the drivers are acquiring a more mellow tone as they are are running in........the bass in particular.It's hard to believe that you could improve on these with different horns & drivers (the V Trac & BMS for example) so for the moment I'll take your word for it, as you have all been down that path & have the benefit of that experience.

Thanks Marvel........I estimate that these would be about half the price of the factory models. I think I've got a pretty good deal.

Sorry about the angle bracket for the mid driver....I just couldn't wait to hear them. I'll fit up a set of wooden brackets soon. And the listening impressions..... Fitted with Crites stamped frame woofers, K55/400 mids, Crites CT125 tweeters, & Crites 4500 crossovers. The midrange is very open & detailed, also very smooth. Not peaky at all & certainly no harshness. Top end is crystal clear & very detailed....once again no harshness at all even at very high levels. Bass is reasonably extended ( cabinets have the bracing on the side walls) but very wooden sounding & lacks warmth. I don't think I could listen to them without a sub, however, with the Velodyne switched in it turns this system into a giant killer. Very smooth bottom end with heaps of slam & almost unlimited headroom. With the sub you can listen at more normal levels & still get that full, live sound. In comparison to my Altec Model 19's, they are not as smooth & not as big a sound. They sound more constricted & don't disappear like the Altecs do. Their plus's are the bass slam, the airiness in the mids & tops & the extension in the top end. So now I have two systems that I can listen to whenever the mood takes me!! I think I have the best of both worlds.!!

Matching grain on the veneer, cabinets spaced with rubber bushes between bass & horn cabs.

Sorry about the towels underneath, them but I use these to slide them around to adjust the positioning before fitting the spiked cones underneath them.

Another angle

Horn cab detail

And another

Cabinets are finally finished.....so here's some shots

Good luck & look forward to seeing some pics.

Excuse my ignorance.....but where are the commercial threads? Would love to see the big Klipsch gear in action. Thanks, John You can all stop looking.....I found it.

Excuse my ignorance.....but where are the commercial threads? Would love to see the big Klipsch gear in action. Thanks, John

Grill cloth detail for the horn cabs