I put in my ALK's today and .........

[Al Klappenberger]

Hi everybody,

I agree with virtually everything that has been said here, even the comments

by "mobile". The big problem here is with my policy of making my network

design public for anybody to duplicate. If somebody who doesn't know which

end of a soldering iron to grab builds my network wrong and doesn't know it,

then tells everybody the design is no good, I get the blame. I expected this

to happen. It's the chance I take doing it.

Randy sent me photographs of the networks he built. It was obvious to me

that the parts he used where not only not very good, they were totally

inadequate! If you look at an Andrew Wyath painting through smoked glass it

will look like crap! I have always said that it's not what you do that

counts, it's how you do it! What Randy did was not his fault. He simply

didn't know the importance of quality parts and sound construction

techniques. The policy of trying it first on the cheap to see if it works is

totally bogus! You CAN NOT do that!

A case in point: I remember years ago, back in my ham radio days, a friend

brought me a radio teletype receiving converter that he had built of a very

popular and proven public domain design. It was commonly know from an

article published called "Teletype without tears". This fellow's policy was

to not solder any connections until he was sure everything was right! To

make matters worse, the building job was so bad that it wasn't worth trying

to do the soldering. Needless to say, the thing never worked!

Randy: I will still look at the network you built, if it still exists, and

take measurements of it's performance and point out any other problems I

see, if you ship it to me. I will NOT rebuild it however. I am curious to

see how those crummy parts translate into performance measurements. As

"mobile" points out, I put quite a bit of faith in them! Instruments do not

lie, they just don't always tell the whole story. You do need to start with

instrument measurements though.

Al K.

[mobile homeless]

I think measurements are an excellent and necessary design tool. Dont get me wrong here. I think their use is ESSENTIAL but only in partnership with educated listening in a variety of conditions. IT is the PARTNERSHIP of the measurements and testing combined with the listening tests that makes a complete product and more full analysis.

I fully agree with Al's last statement in that measurements dont always tell the WHOLE story and sometimes DO NOT correlate with good sonics, something that a few here fail to grasp. There are many pieces of gear which measure very well with a sonic performance that is not up to par.

I am curious as to what parts RAndy actually used in his crossover attempt. Al, do you remember? Randy, can you post the parts? I am a firm believer in parts quality although it sometimes can be surprising. With the 2A3 SET monoblocks, there are so few parts in the circuit, you can really hear the results of rolling caps, resistors, and other components.

In another comparison, even though the Caddock resistors (a very high quality part) measure better in some ways than the Audio Note Tantalums, I found the Tantalums to actually be smoother and more true to the music, without the slight tint of glare that rides along with the Caddocks, still considered a very nice resistor.

So again, I think measurements ARE important, but listening sessions should also be used in conjuction. Ultimately, I give the listening the final say, even if something happens to measure better. I have several solid state offerings that have mearsured better than any of my tube amps, especially in the time of using high amounts of negative feedback to reduce distortions measurements to vanishing levels. And this equipment sounds dreadful compared to amplifiers with a finer pedigree if not measuring status.

kh

This message has been edited by mobile homeless on 09-03-2002 at 11:02 AM

[Al Klappenberger]

Mobile,

I just reviewed the pictures Randy sent me of his network attempt. I am not

able to tell from the pictures what the capacitor are except that they are

very small. The two 2.2 uFd (which are very critical to the performance)

were about the size of the fuse holder I use! They may even be nonpolarized

electrolytics, but I am not sure. The inductors are of fine gauge solid wire

on plastic spools. The woofer inductor (2.4 mHy) in particular would have

sucked up a lot of the bass.

Randy is going to have to specify what parts he used.

Al K.

This message has been edited by Al Klappenberger on 09-03-2002 at 08:08 PM

[John Warren]

Mike-

Correctly wired, high output direct radiator drivers can easily match the output of the folded unit. For example, the JBL 2123J is a 16 ohm unit with a sensitivity of 98dB/W/m. A pair per channel, wired in parallel results in a 6dB/W/m boost (impedance drops to 8 ohms for +3dB and cone area doubles for +3dB). The net result is an array efficiency of ~103dB/W/m over 500-1500Hz with power handling capacity that is near 500W. They will make you jump out of your socks, the dynamics are very good.

The tweeter-

A number of decent tweeters can be used to match including my favorite bi-radials the JBL 2404 or for cost concerns the very good Beyma CP25. They are titanium alloy diaphrams capable of real high frequency extension. The Avedon T-35 is a relic, albeit a *cool* looking one. It belongs on the shelf as a collectors item.

I will publish a series of photos of this arrangement in the near future.

[TBrennan]

John Warren---In a recent conversation with Bruce Edgar he told me that the response of the T-35 above 10khz was simply a series of spikey break-up modes. I have heard good systems using the tweeter but it's hardly the thing I'd pick with a clean slate.

[Mike Lindsey]

quote:

---

Originally posted by John Warren:

Mike-

Correctly wired, high output direct radiator drivers can easily match the output of the folded unit. For example, the JBL 2123J is a 16 ohm unit with a sensitivity of 98dB/W/m. A pair per channel, wired in parallel results in a 6dB/W/m boost (impedance drops to 8 ohms for +3dB and cone area doubles for +3dB). The net result is an array efficiency of ~103dB/W/m over 500-1500Hz with power handling capacity that is near 500W. They will make you jump out of your socks, the dynamics are very good.

---

Will the JBL 2123J mate up with K400/K401 and ALK crossovers? As you can tell, I'm not as technical as most of you but am willing to learn here and try new things. I will let my ears decide what sounds good to me.

quote:

---

Originally posted by John Warren:

The tweeter-

A number of decent tweeters can be used to match including my favorite bi-radials the JBL 2404 or for cost concerns the very good Beyma CP25. They are titanium alloy diaphrams capable of real high frequency extension. The Avedon T-35 is a relic, albeit a *cool* looking one. It belongs on the shelf as a collectors item.

I will publish a series of photos of this arrangement in the near future.

---

My question is the same regarding the JBL 2404. Will it mate up with the ALK's and if not, what do I need to do? This is not something I will jump into but eventually, I would like to pick up some of these drivers and give them a whirl.

Thanks for your time,

Mike

[John Warren]

Mike-

The 2123 is a 10" cone pro driver. Used for high output, hifi reproduction (studio monitors, sound reinforcement at concert hall, critical listeners). Used where *horn honk* can't be tolerated. The arrangement I described does away with the OEM midrange horn, driver and tweeter. A new crossover is also rqmnt.

Tom-

Agreed. I'll admit that my hearing is not what it used to be in the HF range but it's not as bad as the T-35 would have me believe.

[Al Klappenberger]

Mike,

I have no first hand experience with the woofer John is describing, but the woofer / squawker filter in my network has such a gradual slope that you could probably use it. I can't sware to it though.

Al K.

[ChuckElliot]

John,

I got the T/S specs for the JBL 2123J from the

JBL web site and calculated the F3 as > 100Hz

for a flat alignment. Am I missing something or

would you intend to use a sub with this driver?

Chuck

[John Warren]

Your missing something--

The 2123J is NOT a woofer, its a mid-range driver.

80Hz to 5.5kHz (+/-2dB). it takes a 1/2 cubic foot sealed box for an enclosure.

A pair would be used to *replace* the Klipschorn mid-horn (plastic thing and compression driver) sitting atop the folded bass unit. It would take (4) 2123Js for a stereo pair (2/side).

This message has been edited by John Warren on 09-04-2002 at 04:57 PM

[ChuckElliot]

Whoops...

I thought something was wrong. I'm still intrigued by the concept of a direct radiator design with this level of efficiency.

[John Warren]

it's nothing new. thats why they are 16 ohms, for arrays.

a pair/side is critical, a single unit doesn't cut it (no punch).

[jweed]

To Randy and Al, I would like to offer my help in the ongoing fued the tow of you are having.

I live in Minnapolis, close to Randy. I have a pair of ALK crossovers built by Al which I use in my K-horns.

I'm willing to take these out and go to Randy's place and hook them up to his K-horns, and listen with him for few hours or so to get and idea of how the TRUE ALKs would sound in Randy's environment.

Jeff Weedman

[Randy Bey]

Jeff,

I would be agreeable to that suggestion. I always say, 'what good is having a mind if you can't change it?'

[Al Klappenberger]

Randy and jweed

YEAH!! -- I like that idea!

If Randy still thinks my networks sound bad after listening to a set that I built, then I will accept his conclusion.

By the way, Jeff has the 9th set I built.

Al K.

This message has been edited by Al Klappenberger on 09-06-2002 at 12:13 PM

[mobile homeless]

In addition, do some serious listening to his system BEFORE you change the ALKs to get an idea of where he is coming from.

I was going to ask if ole Al would send me a pair for my 77 CW to review, perhaps for a publication. But then realized he has absolutely no reason he would want to do this! heh... Cant say I blame him. He probably has enough orders already without any more publicity, good or bad.

kh

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Phono Linn Sondek LP-12 Valhalla / Linn Basic Plus / Sumiko Blue Point

CD Player Rega Planet

Preamp Cary Audio SLP-70 w/Phono Modified

Amplifier Welborne Labs 2A3 Moondog Monoblocks

Cable DIYCable Superlative / Twisted Cross Connect

Speaker 1977 Klipsch Cornwall I w/Alnico & Type B Crossover

Links system one online / alternate components / Asylum Listing f>s>

[sunnysal]

that's what I love about this B-board, the community aspect. We all will be waiting to hear the results of Randy "X-off"...tony

[jweed]

Randy,

I'll send you and email with my phone number. This coming saturday I'm available, otherwise the following weekend sometime.

Jweed

[KanedaK]

Geez, we never had the end of the story!!!!!

[Mike Lindsey]

Yeah, to be honest I can't remember if they ever hooked up. Al may be able to shed some light on it though. I can honestly say I love my ALK's. I have heard a number of networks with my since sold La Scala's (AL's, AL3's, AA's and ALK's) and much prefered the ALK's. I am now using a pair with my modified Khorns (V-TRAC/BMS/Beyma CP-25) and they are definitely the cats meow.

Mike