Atlas PD-5VH versus late production K55V

[BEC]

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On 5/8/2005 9:39:09 PM DeanG wrote:

Well, in the old networks, there is no bandpass section for the squawker, so there is nothing to cut the output of the driver. The tweeter comes all the way in at around 5.8kHz, but the midrange driver's output just goes and goes until the horn says it can't no more. If you look at the plot at the Atlas site (or in the other thread where we posted it), there is a "bounce back" in the driver's output at 9kHz, IOWs, the driver's output trails off, and then shoots back up in the form of a spike. You don't need a graph to see the spike, you can feel it driving into your forehead.

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Dean,

Now you tell me! I have been trying to figure out a way to hear that glitch and never thought to check for a hole in my forehead.

Bob

[Deang]

LOL, I probably have the same hole. I don't think I've ever heard it either. If I have, it would have been back in the 70's, and might explain why I was negative about the Heritage sound for as long as I was. We know all of single port phase plug K-55-V&X drivers have the elevated response at that point, but we also know that with the older drivers -- only 2 in 5 had the problem bad enough to be audibly annoying. If the elevated response never rises above the tweeter's output at that same point, one probably can't hear it. We might deduce there was something inherent in the manufacturing of the time that contributed to it (some slop in the tolerances, or the tooling). With today's CNC processes, who knows, it might not even be an issue any more. Hey, and the new ones do have soldered lugs.

[dodger]

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On 5/8/2005 7:53:39 PM Al Klappenberger wrote:

Guys,

If a PD-5 goes to 10Khz than a T-35 goes down to 20 Hz. Try it, I'm sure you will hear a buzz (for a few seconds)!

A PD-5 is good to 6000 Hz, NO HIGHER!

Al K.

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Then I would ask why they publish the spec of 10,000 and the PD-4 to 7,000.

I would also wonder why Atlas would repeat the same thing twice - two different people.

1-800-876-3333

I did not print the cut sheet, but I did make the calls.

Unless the difference is the size of the driver as I notes. On the old sheet the driver looks to be larger and shaped like the old green bullet harmonica microphone by Shure.

2nd:

There is a similar bounce up at about 18,000 but not as drastic.

Noting the 2001 sheet; Application

"the drivers...provide uniform, extended response and clear, natural sound reproduction in high and mid-range frequencies..."

"FEATURES:" Extended frequency response range for optimum Intelligibility"

If we say 6,000 HZ then look at the Atlas sheets We have the 35 watt 75 - 10,000 CPS (HZ) or the 2001 which states a "plane wave response of 110 - 4,100 HZ plus minus 5 db but which the graph conflicts with by showing a higher and lower response.

Tis a tad confusing. But it's from Atlas.

Note the 2001 specs are for a 40 watt driver

[Al Klappenberger]

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On 5/8/2005 9:29:28 PM BS Button wrote:

Then why do we even discuss a glitch at 9Khz, if it only goes to 6Khz? And have we concluded that the darn thing is the same driver as the K55V or X without the dual port phase plug or whatever that thingy is called.

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THAT'S WHY WE CALL IT A "GLITCH"!!

The PD-5 is the early K55V with the push-pin spring-loaded connections.

Al K.

[Al Klappenberger]

Dodger,

The answer to why atlas says it will go to 7K, or 10K is very simple. Manufacturers very often do not tell the truth! The curves and many years of producton by Klipsch says that it only goes to 6000 Hz!

I believe the two-piece phase plug was to kill the glitch rather then adding a filter in the netwrok to kill it. This makes good sense from a manufacturing point of view by Klipsch. Why solve a problem with a vendors product by changing YOUR designs. Make THEM fix it!

Al K.

[sunnysal]

plane wave tube measurents always result in frequency extension on the top and bottom versus real world application and measurements, plane wave tube data should basically be ignored in our context.

when atlas says it goes to 10k it does not say how far down the signal is at that point, I suspect at least 10db down at 10k...

tony

[dodger]

For laughs I thought I would try Atlas again.

The person answering this time said that 4,100 was its total high end. It would not reach 6,000 HZ.

Does anybody really know what time it is? Or do we go 2 out of 3 isn't bad.

[BS Button]

Well, my PD-5VH's sound just fine...and Woodog thought the sound drastically improved from that of the K52H's, but that's with new cans, so I'm back being confused again.

BS

[Al Klappenberger]

Guys,

I am convinced that the curve I posted at the top of this thread is neary correct. Compare them with the curves of a K55 on three different horns on my web site. The compare very closely. Those curves were done outdoors and are therefore anechoic (By Lee Clinton). This tells me that the PD-5 is just an early K55V and they go nicely to 6000 for out purposes and that's it.

Al K.

[BS Button]

From there they need to be Extremely sloped and crossed over to the tweet, eh?Alk? Omigod, I'm starting to catch on...

[Al Klappenberger]

BS,

Yes, you have to cross over to the tweeter at 6000. Klipsch never bothered to filter off the squawker becasue it naturally drops off at 6000. This is why the 9 KHz glitch comes through.

Al K.

[Klipschguy]

I've been listening to the old pushspring K55V's for years in my '77 Cornwalls and never noticed any 9000Hz glitch problem.

How much does the K600 lense attentuate 9000Hz?

I would guess the K700 lense would have less attenuation at 9000Hz since it is smaller. If my reasoning is correct (and it may not be since all the heritage squawker lenses have basically the same flare rate), then the 9000Hz glitch would be most problematic in the Heresy and least in the Khorn (and La Scala).

Andy

[Al Klappenberger]

Andy,

The squawker horn doesn't attenuate 9000 Hz at all. It comes out at you like a flashlight beam! You would hear it as a harshness. Not all early K55v's had the glitch. Maybe your one of the luckey ones without it.

Al K.

[dodger]

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On 5/9/2005 6:27:53 PM BS Button wrote:

Well, my PD-5VH's sound just fine...and Woodog thought the sound drastically improved from that of the K52H's, but that's with new cans, so I'm back being confused again.

BS

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It's okay to be confused on that point as Atlas is only showing spec in their print material as 110 - 4,100 plane wave. They don't list a full response anymore.

[JohnA]

Dean and all,

I don't think you should use Al's graphs to do anything other than compare the response of what amounts to a spring terminal K-55-V to a solder terminal K-55-V. The solder terminal goes higher, we all knew that. The HF gain of a K-400/500/600/700 will be different from Al's horn and the actual upper limit of usable frequencies will be different. Notice how Al's 9k glitch is now 9.5k and much higher in amplitude than what we are use to seeing.

In DfH Vol 19, No. 1, Klipsch says the change was for improved frequency response. In the Rolling Stone article about K&A (I can't find my copy) I believe it says the phase plug was modified AND moved closer to the diaphragm for better HF. Naturally, this would hurt LF output, allowing the disphragm to make contact at lower power levels; reason enough for Atlas not to sell the Klipsch design for other applications.

Note in the attached that the 100.7 dB rating and the curve are on a plane wave tube at 1 mW. Response on a horn will not be the same.

atlas PD-5VH.pdf

[Al Klappenberger]

John,

Here's a plot of the very same PD-5 on a Klipsch K400 horn. It looks to me like the "glitch" is in the same place as on the Trachorn. I didn't post this plot before becasue I wasn't able to. I kept getting some error message about the computer having a problem with the file every time I treid to upload it!

Anyhow, It looks to me like it might just be production variations between the modern PD-5 and the spring terminal K55V of years ago. The PD5 is definitly more like the spring terminal K55V than anything else we know of!

BTW: Remember that the SPL levels were measured with the mike the same distance from the DRIVER, not the horn mouth. This was done to compare horns. The K400 is longer. If I had put the mike the same distance from the mouth of the horns the longer horn (k400) would show a lower level.

Al K.

[colterphoto1]

Just bought two of the 5's that BSbutton got recently from Bob C. and reading this, I'm confused. Are these as good as the 4's or any of the Klipsch K55? models. Todd told me that they were the Atlas version of the K55X, but reading this thread, I don't know what to think.

Michael

[BEC]

The K-55X is a PD-5Vh with a Klipsch label. The PD-5VH is also the same as the K-55V with the push pin terminals, that is, it has the one piece phase plug. The latest model K-55V with solder terminal differed from the earlier K-55V with push pins and from the new K-55X (PD-5Vh) in that it had a two piece phase plug. Very few of those were made.

Bob

[colterphoto1]

Thanks Bob, so this unit is actually superior to most of my inventory of K55M and K55V's in my Cornwalls and LS?

The chart at the beginning of this thread had me so concerned that I barely slept tonight. It appears that the Atlas unit falls off much earlier than a K55, perhaps leaving a hole between 4K where the mid tapers off and 6k where the tweeter comes in. WOuld the Atlas unit need the 'Ptrap' modification done to it? The E networks in these Heresies look like they were made yesterday. Clean shiny caps, no leakage, etc.

Of course the metal horns will get the caulk treatment.

I've got so much stock right now that ghastly as it sounds, I'm considering swapping some parts from originals to create some 'super' breeds. For instance, the Heresies that BSButton reveneered also had the alnico K77's. I'd consider maybe putting them and the Atlas 5's in my single pair of home LSBR's. I've got alnico K77's, earth K77's, K79's. Every mid driver you can think of. K33's are the only stable item.

I think any swaps should aim toward making all my HT Cornwalls a 'matched set'. Sound correct?

This is getting so complicated that I'll probably start another thread for the Colter Swaparoo.

Thanks again Bob, perhaps I can sleep now......

Michael

[BEC]

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On 8/18/2005 3:48:28 AM colterphoto1 wrote:

Thanks Bob, so this unit is actually superior to most of my inventory of K55M and K55V's in my Cornwalls and LS?

The chart at the beginning of this thread had me so concerned that I barely slept tonight. It appears that the Atlas unit falls off much earlier than a K55, perhaps leaving a hole between 4K where the mid tapers off and 6k where the tweeter comes in. WOuld the Atlas unit need the 'Ptrap' modification done to it? The E networks in these Heresies look like they were made yesterday. Clean shiny caps, no leakage, etc.

Of course the metal horns will get the caulk treatment.

I've got so much stock right now that ghastly as it sounds, I'm considering swapping some parts from originals to create some 'super' breeds. For instance, the Heresies that BSButton reveneered also had the alnico K77's. I'd consider maybe putting them and the Atlas 5's in my single pair of home LSBR's. I've got alnico K77's, earth K77's, K79's. Every mid driver you can think of. K33's are the only stable item.

I think any swaps should aim toward making all my HT Cornwalls a 'matched set'. Sound correct?

This is getting so complicated that I'll probably start another thread for the Colter Swaparoo.

Thanks again Bob, perhaps I can sleep now......

Michael

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The PD-5VH is not superior, it is the same as the old K-55V with push pin terminals and the new K-55X. The K-55M is different but similar and some think it is better.

According to posts in this forum over the years, about 20 percent of the old K-55Vs could profit from the P-trap. I have not personally found one that had the peak at 9Khz high enough to be audible. The P-trap introduces its own negatives and in my opinion probably does more harm than good.

Now on rope caulk, I can't see how it does anything on a properly mounted horn. I can tell a bit of difference on the bench, but not once the horns are mounted. I have never put any of that stuff on a horn, but have invested a lot of time removing that nasty stuff off horns I have bought.

Shiny caps are almost always bad.

Bob