Tests: K-69-A driver on Edgar type wood Tractrix horn

[Al Klappenberger]

The passive network I am thinking of IS terrible. There is no axe to grind about it. What axe would I be grinding when I do NOT offer a Jub network and have no plans to do so? If anyone wants to make a point of this, see the Klipsch management! I have nothing more to say about it!

I was not able to find the computer file on the network I am talking about. I may be able to find some paper print out of it someplace. I will look for that next. If someone will post the network design THEY are referring to, I will look at it with the computer. It also needs to be established that THIS driver (K-69) was used with the network in question in the Jub. Until then, the discussion of networks for the Jub is not relevant!I Discussion of networks for THIS driver would be however.

Simple physics says you can not add energy to boost a response that is sagging without using an active device. You can only attenuate the high sensitivity areas. All you can do to add with a passive network is to allow the impedance to drop slightly sucking more power from a voltage source, witch an amp is. That is only good for a couple dB. It will overload an amp if taken to far. If a passive network was used, something else was done, like cutting down the woofer! I consider that UNacceptable. I suspect this driver was NOT used.

Al K.

[Al Klappenberger]

I just located the paper drawing of the network I am talking about. It specifically states that it is "KPT-KHJ-LF, KPT-402 HORN AND K-96-A DRIVER CROSSOVER". I stand by my conclusion that it is a TERRIBLE design and that is my last word on the subject. In fact, I see no reason to return to this thread. I have presented my tests on the K-69 driver and conclude it is a good driver for use in the Khorn as a squawker because if its low cost. There are better ones, but none I have seen so far for the price.

Enjoy.

Al K.

[mikebse2a3]

Just to clarify some misinformation being posted.

The $3000 passive being spoken of were based on a design for the Jub-K402-TAD4002 and was in part an experiment to take the design to it's extreme limits in parts quality because this individual loves to push the envelope when it comes to his system..![]

The orginal passive design for the Jub-K402-K69A does not use padding of the LF section. As with any passive there is some small amount of efficiency lost due to it being a passive network versus the active based Jubilee systems. There is a small range of padding available for the upper-end response and as far as I'm aware most people did use some padding for taste.

I really don't want or have the time to get into any debates on this subject. It would be nice to see factual information being posted and not just misguided or misunderstood conclusions being posted based on limited information with very limited or no real experience which only serves to cause people to draw the wrong conclusions.

If I get a chance I will try to locate and post a frequency response curve that was given to us all in the past but anyone from the forum reading this should know that so far test like frequency response and IM just give us a limited view of what we hear from any given driver/horn and system and there are other test that can also expose the difference between drivers that we hear that these test want expose to us because of there inherent limitations.

Edit: Showing frequency response plots without polar responses also can't even begin to describe what a Driver/Horn might sound like in a room. I will guarantee you if you compared two horns(loaded with identical drivers and both adjusted to have almost identical on axis frequency responses) but each designed and exhibiting different polar responses there would be large differences in their sound experienced in a normal listening room.

mike tn

[mikebse2a3]

Passive is upper frequency response plot in black.

Active-EV DX38 frequency response plot is the lower one in yellow.

These were taken by Roy in the anechoic chamber at Klipsch.

As can be seen the active approach does give an overall tighter response window and around 14K to 15K there is some early rolloff beginning with the passive versus the active approach.

mike tn

[colterphoto1]

Thanks for the testing. What did you think of the sound of that particular horn/driver combo?

[greg928gts]

I think this is a cool picture.

Greg

[IB Slammin]

No passive network is going to be any good with this driver on any speaker higher then 90 dB sensitivity. If it's the design I am thinking of, it's TERRIBLE!

"Me thinks he has an axe to grind,"

BTW: I would think that kind of advertising is best done on one's own website.

Chris,

I have listened to the Roy passive networks in question and loved them, but think that they were in front of TAD drivers not K-69 drivers. Granted there was a degree of insertion loss that effected the low watt tube amps driving them, they were wonderful with acoustic and non-complex music. Blues and Jazz. The analouge properties of the passives were outstanding.

That said and with all due respect to the two engineers of record, I love my custom ALK ESN dbb 450 networks. Just hate crossover smire between drivers. I want to keep the LF in the bin and the mids and tweet in a top horn. Be it two way, three way, horn loaded or reflex.

I must think that if someone were advertising here, and that person was all about sales........Why would he offer his network designs and part lists for free on his website???? Just can't see the advertising going on. Only product test information. ?????

tc

[Coytee]

I think this is a cool picture.

Thank you. I've always been kind of partial to it as well....even if I did get suspected of photo-shopping it when I first posted it!

[Y]

[Chris A]

I must think that if someone were advertising here, and that person was all about sales.

How you say it has everything to do with the message. I was commenting on the manner of delivery.

Chris

[mark1101]

I can tell you that in the active scenario Roy has spent a good deal of time optimizing the K69 as a HF 2-way system driver. I heard it compared to several other drivers and it is hard to beat. The TADs were the only drivers I felt were significantly better but the others that SHOULD be better MIGHT have been by only a small margin but did not sound as optimized to me when varied types of music were played. With the proper hand tuning the system, you can get more performance than you'd expect out of a K69. I also heard its limitations. But I would expect the K69 to sound very good in a Khorn.

[homemadeheresy]

Are you sure they are the PAudio BMD 750 drivers? Just scanning the internet I found that the Resonant Frequency (fs) is


595Hz. Would a driver function properly crossed overbelow its Fs by 100 Hz and would it be able to handle any amount of power without coming apart??

[Chris A]

I heard it compared to several other drivers and it is hard to beat.

I think it is important to note that the horn that the driver is connected to has a lot to do with their performance (horn and driver). Since most audiophiles listen to direct radiator systems, they equate the linear superposition of each standalone driver's performance with the performance of the entire speaker system. This really isn't true for horn-loaded systems (IMHO), and PWK spent a good portion of his life proving that extremely good speaker systems did not require the most expensive drivers, thus making his systems affordable to folks like those on this forum. [Y]

Point in fact: most compression drivers have warnings against being driven without a horn or waveguide attached. (I wonder why...) If the K-69A was tested and the results didn't look that good, then I'd say "look at the horn it was connected to".

I listened to K69As for a couple of years, and I can tell you that they did have very good performance when mounted to a K402 horn. I bet Islander can attest to their performance when connected to the K-510 horn. Those two horns are available from Klipsch. I recommend talking to Roy Delgado if you have interest in either of them (with drivers attached).

Chris [8-|]

[Marvel]

Are you sure they are the PAudio BMD 750 drivers? Just scanning the internet I found that the Resonant Frequency (fs) is


595Hz. Would a driver function properly crossed overbelow its Fs by 100 Hz and would it be able to handle any amount of power without coming apart??

I was told...

The K-69-A is a stock, off the shelf P.Audio BMD750. It's basically a clone of one of the B&C drivers with a 2.75' voice coil (instead of the 3" VC the B&C drivers have).

[Guest David H]

The K-69-A is a stock, off the shelf P.Audio BMD750. It's basically a clone of one of the B&C drivers with a 2.75' voice coil (instead of the 3" VC the B&C drivers have).

This is all great info, Thanks for running the tests and sharing.

Dave

[djk]

I believe it is 2.84", a copy of the geometry of the original Altec large format driver called the 284 (strange? The same designer made a driver with a 1.75" coil and called it a 175!).

http://www.bluearan.co.uk/index.php?id=FANCD280-8

Same driver, different back cover.
(£83.40 ex VAT or $135.897 USD)

http://www.usspeaker.com/paudio%20bmd750-1.htm

[Islander]

I believe it is 2.84", a copy of the geometry of the original Altec large format driver called the 284 (strange? The same designer made a driver with a 1.75" coil and called it a 175!).

http://www.bluearan.co.uk/index.php?id=FANCD280-8

Same driver, different back cover. (£83.40 ex VAT or $135.897 USD)

It looks at first glance like you posted the listing for the Fane driver that's one line above the P.Audio driver, as you can see on this page. The specs of the two drivers are a bit different.

http://www.bluearan.co.uk/index.php?category=Speaker_Components&masthead=High_Frequency_Drivers&subheadnew=Compression_Drivers

In any case, they sound much better than the K-55V/K-77 combo.

[Deang]

Only on the Klipsch Forum does old news become new and revelatory three years later.

[Deang]

Of course, we later learned that the driver wasn't modified at all, but just off the shelf bmd750s. We also later learned that there seemed to be quite a bit of varience in the performance of these drivers.

Finally, and I'm sorry I have to say this -- but how does a driver with a smaller VC and a completely different diaphragm become "a clone" of a B&C?

If the subjective performance of this driver is acceptable, then why are most of the users of the thing dumping it as soon as they can afford to?

[Marvel]

Of course, we later learned that the driver wasn't modified at all, but just off the shelf bmd750s. We also later learned that there seemed to be quite a bit of varience in the performance of these drivers.

Finally, and I'm sorry I have to say this -- but how does a driver with a smaller VC and a completely different diaphragm become "a clone" of a B&C?

If the subjective performance of this driver is acceptable, then why are most of users of the thing dumping it as soon as they can afford to?

Sweet! You posted this:

The K-69-A is a stock, off the shelf P.Audio BMD750. It's basically a clone of one of the B&C drivers with a 2.75' voice coil (instead of the 3" VC the B&C drivers have). Roy told me it was so similar that B&C sued P.Audio over it. When I thought about dumping it, DJK told me not to bother unless I was will to take a major step up. He told me it's a very good driver.

Yes it's old info, but most don't remember it. I guess if you can afford to buy Jubs in the first place, you can eventually own TADs. And you can't get the 402 horn without the driver, so of course folks will DUMP the K-69 when they can.

[Chris A]

And you can't get the 402 horn without the driver, so of course folks will DUMP the K-69 when they can.

Not so fast...

These drivers are good enough that the real issue is getting spare K510-like horns to use the "leftover K-69As" on other speakers. I'm looking at alternatives to the K-510 because of the comment by Roy that the horn cannot be procured without drivers attached.

So...I'm thinking about something like this, although I'd still go with the K-510 if it were available in horn-only configuration, so that I could mount my existing K-69As. I wonder if Klipsch would grant special dispensation and sell a couple?

Chris