Beyma CP25

[DizRotus]

I see that Al Klappenberger supplies the CP25 with his lovely wooden squawker horn, i.e., I assume that it's comparable to, or better than, the K-77/T-35. Any input regarding the relative merits of the two units, (including input from A.K. himself) would be appreciated.

My ultimate plan is to mate wooden squawker horns (Al's or a homemade version) with Khorn bass bins. The X-overs would be AK or similar. I have T-35s and K-55s. Would the Beyma CP25 be an improvement over the T-35?

[Hardhead]

I don't believe Al actually supplies the Beyma CP 25 with his Trachorns; I think he will supply a bracket on the Trachorn mounting board to install a CP 25 if you request one.

If you have the round magnet Alnico K-77's, you'll be surprised at how much cleaner and clearer the CP 25 sounds and at how much music you've been missing with the K-77. I can't explain it, but a better tweeter like the CP 25 seems to make the midrange sound better as well. The CP 25 plays a dB or two louder than the round magnet K-77, but I got used to it after a couple of playings, and now I don't notice it.

If you have the square magnet K-77-M's, get ready to be amazed when you hear the CP 25's. Al has posted some graphs that show, among other things, that the K-77-M is SEVERAL dB's louder than the K-55 midrange mated with a midrange horn, especially near the crossover point. The square magnet K-77-M, to my ears anyway, is JUST TOO LOUD and is, in my opinion, responsible for the reputation for harshness and the wire-in-the-ear effect that many people think Heritage speakers have. When properly attenuated by several dB's, they sound as good or perhaps slightly better than the round magnet K-77's, but attenuation of the K-77-M's is mandatory for me. The Beyma CP 25, though, is at or near the level of the midrange so it doesn't need attenuating and will sound so much smoother than the stock K-77-M's. You'll be shocked at how much better you like the CP 25's than stock K-77-M's.

At $150 each the CP 25's aren't cheap, but the difference in clarity was worth it for me. If you're concerned about cost vs performance, you can always order one and listen to it. If you don't like it, you can return it and get your money back less the restocking fee. You'll like it, though.

[sunnysal]

I think a better tweeter is a good investment for klipsch heritage speakers. The beyma is a good choice and cheaper than the JBL2404H (the "other" great choice). I think the midrange horn is a great thing to change as well, though I think you should consider a better driver (altec 290, 288H, 299A, BMS H4591, JBL 2485J), not just the horn, when taking that path. regards, tony

[Al Klappenberger]

Guys,

Total agreement all the way!

I supply brackets for the K77 , Beyma CP25, or the big JBL with the grill frame as standard options.

The Beyma is a lot nicer tweeter than the old k77 / T35. It's a much more modern design. I has better dispersion, will handle more power and goes all the way to 20 KHz too. I think the Big JBL is probably better yet but it costs a lot more.

AL K.

[Al Klappenberger]

Here's a comparsion plot of the K77 versus the Beyma CP25

Al K.

[Al Klappenberger]

Here's a plot of the big JBL 2404 .

Al K.

[Al Klappenberger]

Here's Beyma's official data sheet plot on the CP25

Al K.

[Al Klappenberger]

Last, but certainly not least, here's the official plot on the JBL 2404h (My plot is a lot prettier!).

AL K.

[Daddy Dee]

DR,

My take on the Beyma is simply that you'd have to listen to see which

you liked better. I have alternated the Beyma and K77 in my Khorns and

have enjoyed listening to both. When I first started listening to the

Beyma I was startled at the "improvement" in sound. Also, it certainly

does look better on paper. I think Al K mentioned something like,

looking at the tracings it "walks all over the K77". I agree. Another

nice thing is that the Beyma handles much higher power without blowing

the diaphraghm like the K77. It is a very good candidate to

replace the K77, IMO. Also, Al K's attenuator circuit is just the right

thing to make the Beyma an easy drop in replacement for the K77.

I'm thinking that I'd like to order a pair of those attenuators and

swap the Beymas back into the system again. As I remember, the Beyma is

rated about the same efficiency as the K77, but to my ears, I think

some attenuation would be good.

I went back to the K77's after a while because I thought my Khorns

(with the Beymas) no longer sounded like Khorns. Part of what I

enjoy about Khorns is imagining Mr. Paul liking the sound when they

went out of the factory. I'm kind of corny like that.

[oscarsear]

Per Audio Kid I went straight for the JBL2404. I got 3 of them, one for each Khorn and the 3rd for a center channel Heresy. When I placed them in proximity to where each of the old tweeters were located they were better but not $800.00 worth. So I started to move them around. Now the 2404's on the Khorns reside on the inner aspect about 1.5 feet above the speaker cabinet and nearly flat to the wall. The 2404 for the center mono channel is placed about 1.5 down from ceiling level and slightly angled into the dispersion field. It's still center but above the Heresy by about 5.5 feet. The entire wall width is only around 18 feet, ceiling height is 8ft. In this configuration the entire system is unbelievable. Never heard anything like it.

It may be that one could make significant improvement using the K77 if it too were mobile. I doubt that it could match these 2404's regardless of locale. They really are sweet. I do not know if they're located in the best position. They work well where they're at and they're not easy to locate just anywhere. Someday soon I'll figure out how to play with other locations.

[Al Klappenberger]

Guys,

There seems to be an interesting factor about these three tweeters in the Khonr and Belle. The K77 looks to have the highest sensitivity about 6 KHz yet I have to cut my Beyma CP25 down by about 6 dB to line them up with the rest of my Belle drivers. The real interesting point is that I measured my Belles at 100 dB sensitivity. You wouldn't think any attenuation would be require since the CP25 seems to be around 100 dB SPL running full out. Go figure!

Al K.

[DizRotus]

All of the input is appreciated. I'd be interested in more discussion about the relative merits of compression drivers for the squawker horn, Atlas, Altec, JBL, TAD, etc. If I go to the trouble to use a Trachorn, which drivers should I consider, and why?

Perhaps this deserves a separate thread.

Thanks,

[Al Klappenberger]

Neil,

I am using the JBL 2426h for the squawker. It's supposed to be a wide range driver in a 2-way system, but it won't go high enough. As a squawker crossed at 6000 Hz it's fine. It sounds as bit cleaner than the K55. The Altec 902 will go higher and will work 2-way if you wanted to do that. The Trachorn will accept the JBL or Altec drivers directly. It has a 1 inch throat. It requires a simple adaptor to use the K55 driver. There is also the matter of power handeling. Most of these fancy drivers won't handle much power down low. The Khorn requires a 400 Hz crossover from the woofer and they were not desinged to go that low. Down there you need to stay with the tough old K55 to be safe. The other choices are to go to an extreme-slope crossover or to make sure you keep the volume down. A friend is using Beyma CP25 tweeters, the Trachorn with TAD drivers in a Khorn driven by my extreme-sloped ES-Khorn (ES400+ES5800) combnation. He has had no problems and loves the combination.

The picture is the Trachorn with the JBL 2426h and a Beyma CP25 tweeter mounted in the grill frame.

AL K.

[Deang]

I like the sound of the K-55-V and K-55-M. I think they are nice sounding drivers. On the Trachorn, they really shine. I've taken advantage of the elevated response the Trachorn provides at the low end -- and I'm running my K-55-V's down to 300Hz. I was going to cut the bass bin back a bit more, but my RTA shows that the AK-3 low pass filter actually supplies a cut-off just about where it should be. At 350Hz it starts falling off pretty fast. It's very tight and clean, and running the Trachorn down a bit lower really cleans up the lower midrange -- voice sounds phenomenal and drum sticks hitting the snare sounds incredibly realistic. The extra half inch at the throat and the big mouth makes a big difference. I don't think you should be looking for new drivers until you've actually heard the stock drivers on the Trachorn. I'd like to see those using low to moderate power with the Trachorn try the lower transition point. I think a hundred watts or less is safe. I've dumped the full 60 watts of my Quicksilver monoblocks into my Klipschorns using some fairly dynamic music and haven't had a problem. Still, this kind of move warrants some caution I think.

I appreciate Hardhead's posts, but this one has me baffled. My take is that the "harshness" is a result of back reflected energy from the mouth of the squawker back into the small throat. The more power you dump into it the worse it gets. Some people actually don't hear it at all, which is amazing -- because it puts me in the fetal position at anything above 100dB. I know it's the squawker because if I cut its output it all but goes away. The quickest way to great listening with the K-400/401 is to kill it before the K-77 comes all the way in. By contrast, the Trachorn can be run full out and sounds glorious. I added a bandpass on mine, but it really doesn't need it. At any rate, squelching the squawker greatly reduces "harshness".

I don't completely trust the FR plots anymore. At some point, you simply have to trust what your ears are telling you. Even with 3dB of attenuation, the CP-25 has a presence that makes the K-77 sound like it's wrapped in a wad of cotton by comparison. Dynamics are simply in another league, and though not always as evident with compressed music material -- is very evident with good recordings (and especially movie soundtracks). Sitting behind the grill-cloth -- my measurements and experimentation show the K-77-M to be fairly weak. I get the best sound using NO attenuation. It's a decent sounding tweeter if you just let it go. If you roll the squawker off you can actually hear that it's a decent sounding tweeter.

[Daddy Dee]

Dean,

Thanks for posting. Is the band pass you refer to on the top end of the K55?

[Duke Spinner]

interesting, Dean ....

the Beyma is a nice alternative pricewise to the 2405

[Duke Spinner]

whoops ...mean't 2404 ......[]

[Al Klappenberger]

Guys,

I agree with Dean about the K55. I replaced mine with the JBL 2426h back when I was using Altec 811b horns. There was a difference. The JBLs were somewhat cleaner, but not by enough to warrant the extra cost. I have Belles crosssed over at 700 Hz though. If you want to cross a Khonr lower, say as low as 300 Hz, you really need to stick with the K55. I like this idea simply becasue it give you a higher over all efficiency. 300 Hz is where the Khorn woofer peaks out. Now that I have the Trachorns in my Belles I may rebuild my netwroks to cross them over lower. All I need to do is get the lead out of my posterior!

Al K.

[consistent]

Hi Al,
Can the CP25 be slipped straight into the AK4 Khorn crossover?

Cheers

[Deang]

Nope.