Atlas PD-5VH versus late production K55V

[Al Klappenberger]

Guys,

Here's a direct comparison between an Atlas PD-5VH driver and a K55V (solder terminal). The K55V goes a good bit higher, but the PD5 goes high enough to do the job. Note the PD-5VH has the 9 KHz "glitch" like the older K55V.

The level is dB SPL sensitivity at 1 Meter from the DRIVER, not the horn mouth.

The horn is my Trachorn prototype.

Al K.

[Deang]

Stupid thing goes clear out to 6K, what the hell did PK need the dual phasing plug for?

[Al Klappenberger]

Dean,

I know for a fact that the PD-5 and the later K55V use the identical same diaphragm, so the 2-piece phase plug must be what gets rid of the 9 KHz glitch.

Al K.

[Deang]

How did you take that measurement Al? You say it's on the Trachorn, but also say it's not at the horn mouth. That meausrement shouldn't look as good as it does -- I'm thinking about the plain wave tube response of 4.7kHz at the Atlas site for that driver.

O.K., the dual phasing plug kills the glitch, but so does a good bandpass circuit on the squawker, as well as the P-trap -- both much simpler and cheaper solutions to the problem.

[Al Klappenberger]

Dean,

The measurement was taken using wideband noise into my SD375 FFT analyzer operating in transfer function mode. A reference attenuator connected to chan "B" samples the amp output giveing precise SPL data assuming the mike is 1 meter from the source. In this case I position the mike 1 meter from the driver rather then 1 meter from the horn mouth. This was so I could change to a longer horn for other tests and have the same distance reference. The mike was on axis of the horn.

Al K.

[ZAKO]

Dean ....Any time you improve the phaze plug (correcting from the start) You eliminate those nasty notch filters & band pass circiuts. Thats where the clarity comes in Ive been harping about. A good foundation is most importent. Then you dont have to go back to patch-fix the mix.

[dodger]

Atlas publishes the specs of the PD-5 to go to 10,000 as per their cut sheet.

They publish the frequency response of the PD-4V with the push in spring terminals to extend to 6,000. The PD-4V was discontinued by Atlas in the late 1960s. The remaining inventory was purchased by a well known Speaker Manufacturer.

[Deang]

Please provide the link, or attach the curve for the PD-5 that shows it goes out to 10kHz.

[dodger]

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On 5/8/2005 11:15:35 AM DeanG wrote:

Please provide the link, or attach the curve for the PD-5 that shows it goes out to 10kHz.

----------------

Contact Bob Crites, I faxed him information that I was sent from Atlas after speaking with them regarding the PD-4V and 5.

EDIT: This was done after the prior discussion of drivers. Since that time I had a second confimation from, the confirmations from Atlas, another long time Klipsch Dealer, an Authorized Klipsch Tech and additionally now one from Indy regarding the use of the PD-4V. Any calls that were not toll free, I paid for myself, including the faxing of the information to Bob.

I'm not looking for a flame.

[BS Button]

4,100 here?

HIGH-EFFICIENCY COMPRESSION DRIVER UNITS.txt

[BEC]

Dean,

The PD-5VH certainly produces sound to 10K. That is easy to prove by just disconnecting the tweeter and input some tones into the crossover. And dodger did fax me a sheet from Atlas that does in fact specify that the PD-5VH has a frequency response of 75 to 10K. However, this spec gives no curve or plus/minus spec on db. We all must consider the fact that Atlas designed this driver as a full range PA horn driver for voice mainly. For music, we have to use a crossover to select a portion of that range where the driver is relatively linear. The horn is also important to the frequency response.

Bob Crites

[dodger]

Please excuse my inability to CCP:

ATLAS SUPER-POWER DRIVER UNITS

and Eplosion Proof Speakers

ALL wITH THE NEW "ALNICO V-Plus" super efficient magneti9c circuit.

First Model Shown is

PD-5VH

Power: 35 watts (tested for integrated speech and music input - that was a notation at bottom)

Impedance: 16 ohms

FREQUENCY: 75 - 10,000 CPS

Shipping weight: 5 lbs.

MODEL PD-4V

Power: 30 watts ( also noted speech/music)

Impedance: 16 Ohms

FREQUENCY: 75 - 7,000 CPS (I erred above stating 6,000)

Shipping Weight: 5 lbs.

Also liste on same page is {PD-8VT

I do have the page with the PD-5VH Impedance chart and also the PD-5VH Wave Tube Response. The wave tube response does show a roll off beginning at about 6,250 but has another peak at what looks like 9,000 Hz then a gentle roll-off to 10,000. Shown on the Artichect and Engineer Specifications page.

They also note actual frequency respons of a driver / horn combination will vary depending on the horn used with the driver. Consult individual horn specifications sheet for typical horn frequency response.

Average sound db level for the 4 and the 5 are 110.7 - per sheet.

In speaking with the Technical Department people that Remember the PD-4V and the PD-5VH, the output levels were whin 1 / 2 db.

EDIT: The Frequency Response was plus/minus 5 db. Plane wave response was liste at 4,100 hz, low frequency limit listed as 250 hz.

The one page is old enough to note CPS, the graph page is new enough to note HZ. I would like to see the page with graphs and Impedance in CPS as that would be the older as the face page I have.

END EDIT

2nd EDIT: The first page denotes a 35 watt driver, the graph page denotes a 40 watt driver END EDIT

[KathyMason]

--Stupid thing goes clear out to 6K, what the hell did PK need the dual phasing plug for?--

Oh Master DeanG,

You really get me sometimes with your tactfulness!

[Deang]

Kathy - If they're not wearing ruby slippers, they don't get tact.

Win, I had no intention of flaming you, I just wanted to see the data.

Bob, thanks for the clarificition. Sure, there's what it does, and then the part is does that we can use.

[dodger]

----------------

On 5/8/2005 3:24:39 PM DeanG wrote:

Kathy - If they're not wearing ruby slippers, they don't get tact.

Win, I had no intention of flaming you, I just wanted to see the data.

Bob, thanks for the clarificition. Sure, there's what it does, and then the part is does that we can use.

----------------

Dean can you email or PM a fax number and I'll send what I have.

I did notice after looking at it a while, the 35 watt specs are a page form most likely the mid to late '60s or early '70s. The 40 Watt specs have a date (duh) of copyright 2001. I wish that I had the additional 35 watt pages with their graphs, they may be more of an answer.

The 2001 graph shows a peak around 9,000 hz.

I meant that by stating my case I did 't mean to flame.

And, I need glasses - the wave tube response is shown as going to 20,000 HZ.

If you "ballpark" envision a buffalo from a buffalo nickel just have the hump smoothed out a bit.

I tried drawing it, but it didn't work.

So we're fine.

Also interesting is that they note the PD-4V as having 6 mounting holes, which I've seen and then I've seen them with the three pins.

It's an interesting page. You've probably seen the 2001, if not and you want it let me know.

Win

[dodger]

Another small print from the early model:

"Above Models include built-in "Uni-Match" transformers offering an impedance match at 160,250, 500, 1000 and 2000 ohms or, based on a 70 watt line the equivalent power of 30, 20 10, 5, and 2.5 watts. Permits a change of sound power output level in steps of approximately 3 db when used with constant 70 volt output amplifiers.

Also re-noted is Power rating for speech and music integrated input."

So if the PD-5VH extends to 10,000 CPS (HZ), but the graph shows an extension the albeit dropped to 20,000 Hz and the PD-4V states to 7,000 CPS (HZ), plus the number of people I spoke with remembers its use (9 people) besides the Heresy, could the PD-4V have been used in other models?

Granted the specs as of the 2001 note plus / minus 5 db, fitting the efficiency profile, The plus / minus of Klipsch, there is still a stated Alnico magnet, 6 screws assuring permanent diaphram location which may have been changed to the 3 pins. Plus the frequency range would be sufficient. 75 - 7000 CPS (HZ.)

If you look at the PD-5VH as per the early cut sheet it looks completely different, while the PD-4V looks like what I have seen in my LaScalas and in a number of Heresys.

The PD-5VH of then looks nothing like the PD-5VH as shown in the 2001 cut sheet.

[Al Klappenberger]

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.

[BS Button]

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.

[Deang]

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.

[BS Button]

I think I get it...I think.