Taming the Tweets

[ClaudeJ1]

Well I finally pried open the schedule and finished upgrading the tweeter sections of my 3 AA networks (bunch of 2 uF audio caps I got free from a friend whose son worked for Harman). I began by upgrading the 13uF caps on the midrange on all 3 channels and THAT was a real reveleation. The K400's never sounded so good.

I had plugged in the JBL 2404's in place of the K-77's using the old caps and that was another improvement, but it hurt my ears on many recordings. Changing to the new caps didn't improve the problem, but everything definitely sounded much "crisper" than before with the 30-year old factory capacitors. Tried going back to K-77's with the new caps, but they sounded very dull after being spoiled by the JBL's. So, thanks to Bob Crites advice and his Autoformers, I dropped the level by 2 dB on the JBL's and they sound fine with the re-capped AA twweter section. Things keep getting better with the latest "taming" of those JBL's which are more efficient than the K77's (the magnets on the tweeters are bigger than the mid driver).

Now I'm working on small Walnut enclosures and new (John Warren) Xovers to make those JBL 2404's on the Khorns "self-contained" and portable. I can't use the third one on top of the LaScala because messes up the CRT on my TV (I'm an HD holdout), so I'm stuck with a K77 in the middle channel for a while.

Has anyone here had similar experiences?

Claude

[Audio Flynn]

Chorus rears in the 5.1system--13 foot "Wall of Sound" from Left to
Right: Khorn, VMPS Large Sub, La Scala, VMPS Large sub, Khorn. Driven
by a $185 refurb Onkyo receiver, B&K Amp on Subs. 23Hz-20Khz with
the JBL 2404H on top of the Khorns.

=========================

Hard to comment if you are using a SS Onkyo receiver to power your K Horns. My take is you are trying to tame your amplification. Both times I heard K Horn with SS was disappointing and shrill. Please consider a new amp. Would be hard to get a sound stage with the wall of sound concept in my 16 x 22 room. 2 speakers are confusing enough for me.

[ClaudeJ1]

Hard to comment if you are using a SS Onkyo receiver to power your K Horns. My take is you are trying to tame your amplification. Both times I heard K Horn with SS was disappointing and shrill. Please consider a new amp. Would be hard to get a sound stage with the wall of sound concept in my 16 x 22 room. 2 speakers are confusing enough for me.

They never sounded shrill until I started to mess with things. The Midrange detail opened up considerably when I put some 13 uF MPoly caps in my AA's. It's like the ESR of my original factory caps were dulling everything. Adding the JBL's is what added the shrillness because they were too hot, even before the new 2uF caps in the AA tweet section.

The -2 DB autoformer tamed the JBL's so the shrillness is gone (it was there even with the old caps). I think when I have the new Warren crossovers, it will be better yet, since they were designed specifically for that driver and not a K77, which is the section what I'm (mis)using now. The 6.1 signal processing and the 5 Onkyo amps are wideband and sound amazing with the right recordings.

I used to have HarmonKardon tubes, then bad SS, then decent SS (Dynaco), then Marantz 8b/recappted Tubes, then Hafler Mosfet, then the Onkyo, so I know what tubes sound like. The differences between tubes and SS have diminished ever since Matti Otala published his paper on Transient Intermodulation Distortion in 1971. Allowing 10 years for the world to catch up, I'd say SS has been darn good for at least 27 years. I used to work with VSP Labs chief engineer (who did a fine transconductance-CMOS amp) back in 1981. He said he had a tough time coming up with a discrete front end as good as Natinoal NE 5534 op amps. I can't imagine that Audio IC's have gotten worse in the last 25 years.

It could be that we need the softer edges of tubes and their promient and pleasant 2nd harmonic distortions in the power amp sections to compensate for the crisp transient response of horns, who knows? But I find the Onkyo's amplifiers to be just fine for now.

Claude

[Audio Flynn]

They never sounded shrill until I started to mess with things.

++++++++++++++++++++++++++++++

I try not to mess to much and if I do I "leech off" the findings of others. My ear is pretty good but I have neither the time with my business travel and 4 kids nor the electrical know how to tweak more than a couple of times a year. I have had the Belles for about 9 months now and have only made one large but somewhat proven mod to ALK Jr networks from Dean G about 3 months ago.

All you monthly or weekly tweakers out there are amazing to me, maybe I can get like that when I retire. You are to be commended.

I am with you in a large degree right up to the implication you sold off a Marantz 8b. Really? Bummer.

[ClaudeJ1]

All you monthly or weekly tweakers out there are amazing to me, maybe I can get like that when I retire. You are to be commended.

I am with you in a large degree right up to the implication you sold off a Marantz 8b. Really? Bummer.

I laughed out loud when I read the term "monthly tweaker" I have had my stock, untouched Khorns for almost 30 years (got a loan for them the week before I got married at 23). Only after I came to this board, about 6 months ago, did I even consider messing with them. I think I have caught the disease and I'm moving forward slowly and carefully.

I just got done litening to Eric Clapton's Concert DVD (recorded in LA) and Cream's Reunion concert at the Royal Albert Hall DVD. This after listening to Diana Krall Live in Paris. All excellent DTS recordings. My system was set up using the AVIA DVD with all the tones and a tripod fixtured Radio Shack Digital SPL meter before Xmas of 2006. THAT made a huge difference even before I messed with the capacitors or added the JBL's. I'm hearing all kinds of details I never heard before. This system kicks some serious ***, espcially when using the "Master and Commander" Canon scenes on DTS!

As for the Marantz 8b, I remember telling PWK, the one day I spent at the Hope factory and his home with him, in early August of 1985, that he coudn't keep it in his museum (the oroginal 16x25x10 room), since I was currently using one on my 3 channel array (I had the bridged resisors/mono center to my lone LaScala). He remarked that it was a very good amplifier. I bought it the day my first daughter was born 25 years ago for $350. Sold it to my best friend's son in the 90's for $750 (it needed tubes). He sold it for $1,200 a few years later. I kinda wished I had kept it now, but I get superb definition from the cheap Onkyo 6.1 receiver, just amazing. My next step is to hook up a set of Heresy's in parallel in the back of the room to get the 6th channel going. It should add more ambience to my concert DVD's and movies. I'm sold on the 96kHz/24bit sound of DVD's for sure and I will try and convert my vinyl collection (600 LP's) to 2 ch. DVD's in the next few years.

[Audio Flynn]

I'm sold on the 96kHz/24bit sound of DVD's for sure and I will try and
convert my vinyl collection (600 LP's) to 2 ch. DVD's in the next few
years.

==================

There are some really cool music DVDs. I may take Christmas 2007 and build the A=>D capability into my computer at 24/88 or higher sampling rate

[meagain]

I'm confused (as usual lately).... You say you have JBL 2404s and "dropped the level by 2db on the JBL's"..... I'm confused about this cuz I thought the various offerings (except Al's Tweeter attenuators), only allowed tap changing on the squawker section. Here it sounds like you are saying you have an option to raise/lower the tweeter section via the crossover. Can someone explain?

Also - "Now I'm working on small Walnut enclosures and new (John Warren)
Xovers to make those JBL 2404's on the Khorns "self-contained" and
portable." Do you have any pics of your 2404 enclosure (assuming you finished it)? And could anyone explain what this John Warren x-over is? Is it designed to specifically run JBL 2404's? And, what is the purpose of this separate x-over for these tweets?

[ClaudeJ1]

I'm confused (as usual lately).... You say you have JBL 2404s and "dropped the level by 2db on the JBL's"..... I'm confused about this cuz I thought the various offerings (except Al's Tweeter attenuators), only allowed tap changing on the squawker section. Here it sounds like you are saying you have an option to raise/lower the tweeter section via the crossover. Can someone explain?

Sure of course. The tweeter section of the AA's contains a 3rd order filter that is optimum for a K77 stock tweeter. I changed the old capacitors for some brand new metallized polypropylene units I got from a friend. Even with new capacitors, the compononent values are the same as the old, so while the sound of the K77 was improved, it's still not as good as the 2404 JBL's. So after plugging the JBL's back into the recapped AA's tweeter section, they were too "hot." So, I purchased a pair of Autoformers from BEC (Bob Crites) on this forum. They allow for a -1 to -12 db attenuation of any component, so I did a lot of listening and the -2 db is the best setting for all my "test" DVD's. The AA's K77 tweter section is normally attenuated with the Klipsch stock autoformer right along with the squawker but it's still too bright with the JBL. In my setup, the JBL gets it's drive throught the stock Klipsch autoformer first, then through the second autoformer I installed just for the tweter. It's on alligator clips so I can mess with it. I am certainly enjoying this combo, but I think I can do better.

Since John Warren's Xover design is optimized for the 2404 JBL "baby cheek" tweeter, I'm going to build them for another pair of 2404's that I have, so I can A/B the two. I'm confident the opimized Xover will win since it equalizes out a hot impedance peak in the 2404, with no autoformer, according to the article John wrote a few years back. Since the AA's tweeter portion does no such thing for the JBL, all I can do is lower their intensity (for now) with the autoformers I got from Bob, until I get the new units built, which will be self-contained and use the autoformers as an option to try with other speakers. They will be self-contained tweeters with their own mini-cabinet, Xover, and autoformer. This way I can bring them to other friend's homes for an audition with their speakers quite easily. Hope that clears it up a bit.

Claude

[Deang]

"...and have only made one large but somewhat proven mod to ALK Jr networks from Dean G about 3 months ago."

What part of the filter did you modify, and what parts did you change?

[ClaudeJ1]

"...and have only made one large but somewhat proven mod to ALK Jr networks from Dean G about 3 months ago."

What part of the filter did you modify, and what parts did you change?

What are ALK Jr.?

I just changed the original caps, same values in my AA's. It made the sound, especially the midrange a lot more CRISP, for lack of a better word. You were actually one of the original people who motivated me to do this, so thank you for that. In the long haul I will probably get to some Jubilees, espcially after seeing Rigma's 1/3 ocatve numbers. Pretty impressive for a 2-way. Until then, I have lots of other components to play with in the off hours while I listen to my improved system.

Next I may also try shorting out the woofer inductor to see what that does in the 350-400 Hz range. My subs take care of the bass down to 20 Hz on a separate amp just fine since I have lots of cone area to take me down there with low excusion of the cones.

[meagain]

He's talking to Audio Flynn re the ALK Jr. (I'd like to know to AF)

Claude - OK, you are saying the JBL 2404 was too hot so Bob hooked you up with some type of autoformer that you put on the tweeter section which enabled the tweeter to be cut 2db. Wow. Since when was something like this doable? Where have I been?

I have 2404's here on loan and am puzzled by the reports of them being too hot cuz they are not hot for me. In fact, I'd say they are a bit lower than my k-77-m's. I always get the opposite result from the general public here.