The air up there

[ClaudeJ1]

A big thank you to all on the forum who steered me toward JBL Baby Cheek tweeters, indirectly and directly. all it took was 16 square inches of foam padding for R&L front chennels to protect the WL sufface of my Khorn tops and 2 pieces of speaker wire to create it. The K-77's are disconnected.

I just listened to Diana Krall Live in Paris on DVD in 5.1 DTS, my front channels' HF performance finally matches that of the Chorus rears. Man, what an amazing revelation of detail.

Why K&A deosn't upgrade the HF sound of Khorns and LaScalas to match that of Cornwall II, III's, Chorus, Chorus II's, Forte, Forte II's, Heresy II's and Heresy III's I'll never know. Why not use a few of THOSE tweeters in parallel if need be instead of replicating the K-77's anemic performance in the last, supposedly inaudible last octave? Thanks to Jim Hunter for creating a better high end for the non-PWK speakers of the 80's, 90's and beyond.

Even though it wasn't as bad as being a Bose listenener, I suspected, now verified that I was missing a whole bunch of music up there.

Claude

[mark1101]

Claude,

Glad you are hearing improvements, but something sounds wrong. The Khorn top end DOES outperform all those other models you mention. The difference being the squawker. I think the Chorus II do have different horns, but not as much top end as a Khorn.

What year are your Ks? Are the networks stock?

Is your HT receiver set to maximize the sound from the L/R. Some of the pro logic DSP options attenuate the L/R on mine. A big difference can be heard when I simply put it to stereo (2 Ch.).

Just trying to help, because a chorus and a heresy should have less top end than a Khorn.

[ZAKO]

Glad to hear the 2404 tweeters made an improvement ...Ive been useing mine now for 16 years, with no turning back.....Nothing like a wakeup call to "chuck" those K77 and go for a clean tweeter.

[ClaudeJ1]

The Khorn top end DOES outperform all those other models you mention. The difference being the squawker. I think the Chorus II do have different horns, but not as much top end as a Khorn.

From an efficiency point of view (higher up taps on the autotransformer), yes, but when Jim Hunter designed the new tweeter series, starting with the Heresy II's, the highs went higher up to a full 19-20K. I had Heresys and Heresy II's for several years and A/B'd them many times. The Heresy II's also had a tad lower bass. Basically the K-77's just poop out at 15K, which never bothered me until I started reading this board and looked for alternatives.

What year are your Ks? Are the networks stock?

The networks are stock AA, but I do no have oil capacitors, they are yellow film caps, which I believe do not age like tha cans did, but I could be wrong. Anyway I only wanted to make one change at a time and just plugging in JBL 2404's was the easiest thing to try.

Is your HT receiver set to maximize the sound from the L/R. Some of the pro logic DSP options attenuate the L/R on mine. A big difference can be heard when I simply put it to stereo (2 Ch.).

Yes, I auditioned the change in 2 channels only. It's a big improment to my 52 year old ears. Yeah, maybe it's a db or so hot at the top, but the crispness and definition of the harmonics from everywhere else is undeniable. Way more "resolution." Heck if you just look at how huge the motor is on the JBL, it make up for the fact the it's dispersing the highs at such a broad angle. It's like having a dome supertweter with the low distortion, effortless perfmance of a horn, because it is a horn (baby cheeks indeed). I believe the baby cheek designs came from Don (D.B.) Keele who was a former Klipsch engineer. I believe he was also the guy who did a Thiele/Small analysis of the Cornwall and found it to be a QB3 alignment.

Just trying to help, because a chorus and a heresy should have less top end than a Khorn.

Well, yes of course, from an efficiency point of view, but not from and extension of highs between 15 and 20k, the last half octave that the K-77 seems to ignore. I would rather have bandwidth slighly beyond my hearing. Opinions here vary from no attenuation to a -2db attenuation. They are fine in my room and I now hear the same high end "tingle" that I was hearing in my rear Choruses, and my studio Chorus II's which have the tweeters that go to 20k. Even if those tweeter only go to 101 db, why wouldn't Klipsch use twin sets of these per speaker to match the K-401's efficiency and gain a broader polar pattern on the highs. I'm sold on these tweeter and I can see why the gurus on the board like those and the Beymas if they are similar to the 2404's. Also, based on my color curve sets from Klipsch literature, I'll be in the market for a pair of Fortes as they have the broadest/flattest frequency response of any other speaker in the old Klipsch line.

[BEC]

Claude,

If you are talking about the caps like the ones in the picture below, they are some truly terrible caps. Notice the ESR reading of 48 ohms.

Bob Crites

[ClaudeJ1]

They are yellow like those, but but they say 200 volts, I think, and they are round. Does the ESR lower the decibels of the Tweeter? If so that may be why they sound fine in place of the K77's.

I have a metal capacitro. just like the other one in your photo is that a 20 Microfarad. Maybe I should just replace those if that's the case. Lemmeno.

Claude "one step at a time for me" Jodoin

[BEC]

For a capacitor, you want capacitance and nothing else.  A good capacitor will read a few hundredths of an ohm ESR.  ESR (Equivalent Series Resistance) is the sum of all losses in the cap and expressed as an equivalent resistor in series with the cap.  If you want to attenuate highs, don't choose to do it with a bad cap.  A bad cap today will stll be a somewhat worse cap tomorrow.  Use an L-pad or tone control or autotransformer to decrease the output to the tweeter, but don't depend on a faulty component to do it.

Bob Crites

[Coytee]

I don't know about all the technical stuff like these other guys but I'll agree with you: When I swapped out my 2404's, that was the SINGLE most noticable change I made to the speakers (other change was Al K's ES networks). I really liked what the 2404's did for the Khorns

[BEC]

The round metal cap was no prize either. Should have been a 13 uF, claimed to be a 14 uF and was actually a 17 uF.

Bob Crites

[ClaudeJ1]

So doing a quick capacitance to ESR ratio on the second capacitor (mid?) I get 150.87:1.

Doing same on the other, and comparing them, the bigger cap is 4,000 times better.

Assuming for a minute that my Xover has the same "faulty" components, at that gross of ratio of "badness" it's a wonder there's any sound coming out of it at all.

Yet, just plugging in new tweeters in the same "bad" Xover a huge improvement over the K77 and matches the timbre more closely of the chorus, whose Xover is probably 10 years younger than my old AA's in the Khorns.

So the big question is what is the SONIC benefit of having lower ESR, or closer to a pure capacitance, as you suggest and what is the detriment of NOT having it.

What is the test frequency of these components? That should have a bearing on the ESR numbers, right? Basically I only spent about $250 for used tweeter motors and lenses. If you break it down by $$per pound and multiply by sonic improvement multiplied by low labor content, I got a hell of a deal.

Now I have no doubt that you have done your homework when it comes to quality capacitors, but how can I possibly make THAT much difference by spending the same amount of money on Caps?

I guess I am in need of serious further enlightenement, so please be my guest.

Claude

[ClaudeJ1]

I would love to see a twin pair of modified K79-K tweeters on modern
Khorns and LaScala II's. K77's completely ignore the last 1/2 Octave
between 15-20Khz and the K79's get there, but with about 3 db less
efficiency, so why not twin them up and get the extra volume AND better
dispersion. I don't think cost would be an issue, just "tradition."

Claude

[BEC]

Claude,

The first cap would have reduced the tweeter output to about 16 percent of the amount the designer planned for the crossover.  It would also have moved the crossover point from mid range to tweeter to a different value.  The second cap would have moved the crossover point from woofer to midrange up some amount.  There is no particular reason to think your caps are as bad as these, but I have never tested a cap from an original Type AA crossover that was good.  Those caps were tested at 1 khz which is the standard test point for capacitors.  If bad there, they are bad as capacitors no matter if they are better or worse at other frequencies.

You don't have to spend a lot of money to greatly improve the caps in your Type AA crossovers.  The cheapest Dayton or Solen Polypropylene caps from Parts Express are huge improvements over worn out lossy caps in the old crossovers.  The cost of those would be perhaps $20 to $30.  I like to use Sonicaps in the ones I build and rebuild and that would cost around $70.00.

Bob Crites

[tigerwoodKhorns]

So doing a quick capacitance to ESR ratio on the second capacitor (mid?) I get 150.87:1.

Doing same on the other, and comparing them, the bigger cap is 4,000 times better.

Assuming for a minute that my Xover has the same "faulty" components, at that gross of ratio of "badness" it's a wonder there's any sound coming out of it at all.

Yet, just plugging in new tweeters in the same "bad" Xover a huge improvement over the K77 and matches the timbre more closely of the chorus, whose Xover is probably 10 years younger than my old AA's in the Khorns.

So the big question is what is the SONIC benefit of having lower ESR, or closer to a pure capacitance, as you suggest and what is the detriment of NOT having it.

What is the test frequency of these components? That should have a bearing on the ESR numbers, right? Basically I only spent about $250 for used tweeter motors and lenses. If you break it down by $$per pound and multiply by sonic improvement multiplied by low labor content, I got a hell of a deal.

Now I have no doubt that you have done your homework when it comes to quality capacitors, but how can I possibly make THAT much difference by spending the same amount of money on Caps?

I guess I am in need of serious further enlightenement, so please be my guest.

Claude

Think about it like putting new high performace tires on a sports car that is very badly out of alignment. The caps need to be in spec to maintain the correct crossover points and behave in a manner that was anticipated by the designer.

Bob is a pro when it comes to crossovers, follow the light...

[BEC]

I would love to see a twin pair of modified K79-K tweeters on modern

Khorns and LaScala II's.  K77's completely ignore the last 1/2 Octave

between 15-20Khz and the K79's get there, but with about 3 db less

efficiency, so why not twin them up and get the extra volume AND better

dispersion. I don't think cost would be an issue, just "tradition."

 

Claude

There is. of course, one completely drop in tweeter that gives that last 5 khz:  the CT125.

Bob Crites

[ClaudeJ1]

OK, so why woudn't they use the CT-125 instead?? Why leave out the last 5K??? I mean for a pair of speakers that cost $5,500 to $7,500 not have as good of a high end as their cheaper counterparts of yore, makes no sense to me.

claude

[BEC]

OK, so why woudn't they use the CT-125 instead?? Why leave out the last 5K??? I mean for a pair of speakers that cost $5,500 to $7,500 not have as good of a high end as their cheaper counterparts of yore, makes no sense to me.

 

claude 

I don't know.  I wish they would, of course, since it is my tweeter.

Bob

[Deang]

The answer is because Jim Hunter and Roy Delgado were not completely comfortable with radically altering 'PWK's speakers'.

[ClaudeJ1]

The answer is because Jim Hunter and Roy Delgado were not completely comfortable with radically altering 'PWK's speakers'.

Well I suppose that, if it's true, it's a reasonable and respectful answer. but a 1/2 octave is a 1/2 octave, so there must be some other overrriding technical reason for not doing so, or one asssigned by management.

Claude