Atlas PD-5VH versus late production K55V

[Deang]

The P-trap behaves like a narrow bandpass. There is some attenuation with it's use, which I don't necessarily think is a "bad" thing. I know we talked about it on the phone, and you told me what the attenuation was -- but I can't remember what you said. I built one into my personal Type A's, and liked what it did.

The K-55-M (ceramic magnet) has a similiar overall response and high frequency extension as the K-55-V with the soldered lugs. I consider it to be a better driver than the K-55-V with spring terminals.

[colterphoto1]

I have the K55M's on a pair of old LS BR's. Are the M's alnico? Is alnico better response than ceramic magnet? Just got the Atlas PD5VH from BSbutton who got them new from Bob (but they are NOT K55anything, just Atlas).

Is there a definitive heirarchy of mid drivers for Klipsch or is a matter of taste? I'm seeing 9kHz 'glitch' vs not, alnico vs ceramic. Atlas with possible 4 kHz high end rolloff.....the controversy seems endless. Are the K55's better than K52 or K53 (I've got some of those in CW and Heresy as well.)

Why is the alnico K77 so prized over the newer ceramic square magnet style?

I've got some of both, should they stay with the network they were assembled with or can I swap at will to put the 'best' drivers in whichever cabinet I wish?

I was thinking that at least having the HT setup match and putting the 'best' drivers in the LS might be a good move. Now I'm even wondering about the much-lauded rope-caulk mod.

The more I read the more I get confused. Should I just put everything back in it's original box and forget all this tweaking stuff? It was fun for a while, now it's just maddening.

Thanks guys, bring me back on board, will ya?

Michael

[BEC]

If I can make it to the heritage gathering in Hope, I could bring some:

1. K-55Ms

2. K-51Vs

3. K-52Hs

4. K-52Ks

5. K-55Vs

6. PD-5VHs

Would make for a maddening listening comparison.

Bob

[BEC]

Michael,

Get those old resisive caps out of your crossovers first and replace with good ones. All else can come later when you are able to really hear what you are doing through good crossovers.

Bob

[colterphoto1]

never mind, I got all confused again. Just got off the phone with Bob, his list is NOT IN ANY ORDER, as I previously thought it was.

I'm just going to let him rebuild my xovers as I get into cabinets, leave mid drivers with the xovers they came with.

Life is simple, Life is good.

It sounds like music to me.

Michael

[Deang]

Those are great driver's Michael, why are you upset? 90% of what Klipsch ever made used those. I think the single phase plug Atlas is a fine sounding beast. When I or anyone else around here says "better", it's often just a matter of degrees. In the Dope from Hope where PK announced the release of the dual phase plug Atlas unit -- he specifically said that the improved measureable response might not be audible. With the great majority of the networks we all use/have in our speakers, the overlap between the squawker and tweeter is a country mile long. In the end, all it really probably means is that since the single phase plug unit (the ones you just bought) drops off just a bit sooner -- you maybe get to hear just a wee bit more tweeter and wee bit less squawker.

The K-55-M's were made by Electrovoice and are ceramic. The K-55-V with spring loaded terminals, the K-55-X (Klipsch designations), and Atlas PD5 are made by Atlas, are all Alnico, and are the same driver. Again, the last letter is the vendor code, not the magnet material. The M's and V's have slightly difference responses, but it is unlikely that it has anything to do with the magnet material. If it does, it's miniscule.

Is there a definitive heirarchy of mid drivers for Klipsch or is a matter of taste? I'm seeing 9kHz 'glitch' vs not, alnico vs ceramic. Atlas with possible 4 kHz high end rolloff.....the controversy seems endless. Are the K55's better than K52 or K53 (I've got some of those in CW and Heresy as well.)

What the PD5 does without a horn on it isn't as important as what it does with the horn attached. The PD5 starts it rolloff around 4.5kHz, but I have plots showing it going out considerably further with a K-400 on it.

Why is the alnico K77 so prized over the newer ceramic square magnet style?

Because some people like the sound of a slightly rolled off treble.

The more I read the more I get confused. Should I just put everything back in it's original box and forget all this tweaking stuff? It was fun for a while, now it's just maddening.

The learning curve can be a bear. Make sure you bookmark threads and take notes. Phone calls help too. Some people are auditory learners.

[colterphoto1]

Is there a definitive heirarchy of mid drivers for Klipsch or is a matter of taste? I'm seeing 9kHz 'glitch' vs not, alnico vs ceramic. Atlas with possible 4 kHz high end rolloff.....the controversy seems endless. Are the K55's better than K52 or K53 (I've got some of those in CW and Heresy as well.)

What the PD5 does without a horn on it isn't as important as what it does with the horn attached. The PD5 starts it rolloff around 4.5kHz, but I have plots showing it going out considerably further with a K-400 on it.

Thanks Dean, I feel a little better now, but I do wonder how the horn could affect the high-frequency response of a driver. Seems like it only controls directivity and the low-frequency point. If the driver rolls off at 4.5 kHz (depending on the steepness of the slope) and the tweeter doesnt' kick in until 6 kHz, isn't that a problem? Seems that there should be pretty significant overlap of the driver/horn combos, so the crossover can control the overlap between the components.

Does anyone have response curves of the various drivers as attached to a horn?

Now I want to get rid of those ALnico K77's. WHy invite more HF rolloff when Klipsch went the other direction, from alnico to ceramic to K79 (in the Chorus II) for MORE HF output? Are these older drivers really prized by some users? Who would possibly want less treble?

Thanks for the lessons guys, I promise to try to be a good student....

Michael

[D-MAN]

I would think that a particular case for hearing the "glitch" would be experiencing excessive sibilance.

Now what's excessive, I'll leave up to you guys.

DM

[michael hurd]

The alnico K-77 have less hf output than the mud magnet. The switch to primarily mud magnets began as a key component of the alnico ( aluminum, nickel and cobalt ) was in short supply and very expensive.

[Hardhead]

Michael--

DON'T get rid of your Alnico K-77's simply because they allegedly "roll off" the highs. Install an Alnico K-77 in one of your speakers and a ceramic K-77-M in the other, turn them on, and then DECIDE FOR YOURSELF which sounds better to you.

I have a few of each kind, and every K-77-M I have has been padded down to match the level of the K-55-V or K-55-M in the same cabinet; the Alnico K-77's don't need to be attenuated. I think the K-77-M is responsible for pretty much all the complaints of harshness and glare regarding Heritage speakers you read about on this forum. Once the output of the tweeter is reduced by 3 dB or so, everything is cool. I can put my ear right in front of the stock K-77-M when it's installed in a cabinet and tell that it's at least a few dB louder than the midrange, whereas the Alnico K-77 is not. I suggest you try that experiment as well.

If you look at the frequency response graphs of the K-77-M, you'll see that it is hotter than the K-77 at and above the 6000 Hz crossover point by at least 3 dB. In that frequency response area the K-77-M is simply too hot for the midrange, and that's what causes the objectional harshness and glare people talk about. The Alnico K-77 simply doesn't do that. Posters are extremely lax about differentiating between the two, but my experience with both models leads me to think I can tell which one they are talking about. I agree that the K-77 rolls off the highs above, say, 10K Hz more than the K-77-M does, and the frequency response graphs also say it does, but my ears tell me that the Alnico K-77's problem is much less objectional, at least to me.

That's my whole point, of course: the above is only what I prefer. Do the tests and find out what YOU like. Tweaking is all about doing the tests and determining what YOU want. Remember, you're trying to please yourself, not someone else.

If you still want to get rid of the Alnico K-77's after you do the tests, send them to me.

I'm not going to get into the midrange discussion except to remind you that the Klipsch midrange drivers have been tested and cherry picked by Klipsch for quality and evenness of frequency response, and the Atlas PD-5VH has not.

[BS Button]

I am under the understanding that some people have actally opened up some of their heritage speakers (and for the first time) only to find an Alnico 77 in one speaker and a 77M in the other?

[BEC]

I bought a pair of 1979 Cornwalls from the original owner. He said they had never been opened and they had one of each K-77 and K-77M in them. I know from "Dope from Hope" papers, that when one of the alnico went out under warranty, Klipsch would only replace the bad one with a K-77M, not both, unless the owner paid for the second one.

Bob

[aaronhoyle]

I have nothing to do with this conversation, I don't know if this is any use or not.. but here it is -

http://www.atlassound.com/techLib/SLSheets/SL2.1551.PDF

[colterphoto1]

That's the part that really bothers me 4100 Hz +/- 5 dB. Wonder what that looks like on a chart.

Michael

[BS Button]

Per ALK, the PD-5 produces sound out to 10KHZ, but only good to 6KHZ, so it naturally begins to roll off where the tweet takes over.

[IndyKlipschFan]

The more I read the more I get confused. Should I just put everything back in it's original box and forget all this tweaking stuff? It was fun for a while, now it's just maddening.

Good points.

If I can offer one suggestion which applies to your front three speakers in a HT situation.. left, center, and right... Keep all of these exactly the same drivers x over etc., etc. This, (if they match accross the front) is the home run! Remember Timbre. The others are, of course, dreamland too if they all match but I have said it till I am blue in the face if you match these three front speakers exactly... your seams will just be outstanding, even with average speakers.

Now set some of these up, or I will come over and do it myself.. hahahahaha

[colterphoto1]

Well, we've got all weekend with no Forum Indy. I have been working on the RB5/RC7 setup in the basement and actually have the HK430 set up with some KSB's in the master bedroom. It's really loud with the plaster walls and oak floors though.

Do ya think those LSBR would be nice in the basement as a 2ch setup? Really the RB's are loud enough for me. Don't know what to do with all these boxes now that I have them.

I'm even getting the idea that many members think the rope caulk trick unnecessary.

Boating Sunday?

Michael

[Hardhead]

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On 8/19/2005 5:43:51 AM colterphoto1 wrote:

I'm even getting the idea that many members think the rope caulk trick unnecessary.

Michael

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

And many people did like it. I did, despite my scepticism; in fact, I still don't believe it works, even though I can hear the difference. I found it to be an improvement when used on the older, thicker aluminum midrange horns. The later, thinner aluminum midranges when caulked sounded worse to me instead of better. TRY IT YOURSELF AND SEE WHAT YOU THINK.

With apologies to Sir Issac: "For every opinion there is an equal and opposite opinion." You're going to get opinions both ways on this forum on just about everything, so you may as well try it yourself and find out what sounds best to YOU, in YOUR room, on YOUR system.

[Deang]

!

[sfogg]

That is a K55V and a K55m on a 511B.

The differences in sensitivity shown there aren't real, I changed the level of the K55V so it would display better on the same chart.

Shawn