K33E - TSP Question

[vwittke]

Hi,

yesterday i managed to buy a pair of used K33E´s on Ebay for an intended DIY LaScala projekt (Not easy to get in Germany). I took them home and measured the TSP. From posts on AA I expected something like: fs=35HZ and qts=0.4.

To my surprise i got:

fs=25HZ, qms=2.6, qes=0.313, qts=0.28, z(fs)=29 OHM

The readings were quite the same on both woofers.

Is an fs=25HZ normal for used K33, are the spiders worn out or are the posted parmeters wrong ? Measuring was done with constant voltage method, Um=1V.

Many thanks for information,

Volker

[BerndH]

Can you send a picture or describe the woofer? Is there a factory logo or stamp, do you see a serial number?

I don't know about measurement, i only know the specs from AA for the Eminence driver:

RE OHMS 3.39

FS HZ 34.46

LE MH .96

MMS GMS 78.59

QM 7.39

CMS mm/N .2714

QE .410

RMS NS/M 2.3037

QT .390

VAS LTRS 301.66

XMAX MM 8.20

SD SCM 889.59

BL TM 11.88

EBP 84.4

EFF % 2.91

SPL dB 96.6

Serial number should be 1520F5637.

But there are several other K-33 drivers made from CTS or Electro Voice, where i don't have any specs.

Bernd

[mace]

Volker,

You can check out this thread for some info on this. Apparantly fs should be 35 Hz.

I'm interested in learning more about these measurements. Could you provide some web links which explains what they are and how to measure? (German language site are OK for me.)

Thanks,

Mace

[djk]

The mass corner frequency is the same. Unless you change the mass or the magnetic strength the parameters will shift in a fashion that will keep certain relationships fixed. If you had the Vas I could cross check some other numbers.

[vwittke]

Thanks to everyone for kind response !

To BerndH : Unfortunately I cant send a picture, but the drivers look exactly like the one in mace´s sick woofer thread. It has a glossy black laquered stamped frame with a square mud magnet and a Klipsch Logo on it. The magnet ist bolted together with two screws. There is a Part Number 67-7811 on the magnet and a sign "KLIPSCH K33" on the rim.

To mace: For a good explanation of TSP and the measuring procedure try this site:

http://sound.westhost.com/tsp.htm

To djk: Last night i measured the compliance by adding a weight of 120g and got CMS=0.7 mm/N. BL is 11.4 N/A, Re=3.2 OHM

I mounted one driver in a closed box of 125l and got fsb=48Hz --> Vas~=335l.

Is it possible to re-stiffen the spider with some sort of impregnation (PVA, thinned silicone or rubber solution)? Perhaps some reader of this thread knows which impregnation of the linen spider is used in manufacturing. Could be of interest for a lot of vintage driver owners!

I have a pair of Eminence Kappa15 Drivers on hand. Could they be used as a good replacement of K33 in LaScala ?

[BerndH]

Volker,

To drivers with your listed part number i have no specs. Sorry.

I don't understand, for what reason you do this measurements. What's the matter you don't trust having a K-33?

How much did you paid for the both drivers?

Do you have the squawkers, horns and tweeters for you La Scala project? Or do you wanna only build the bass bins? If needed, i have one K-55 V mid driver and two K-400 metal horns, which i would sell.

What you can do at this point is building the LaScala bass bins. You need for the raw bass bins about a weekend, that's short. Then test the speakers you have. But i believe you will not be satisfied with the Eminence Kappas.

I ran my Klipschorns, until i bought new K-33 drivers, with Eminence 15-B300 and what i can say today, they sounded bad with weak bass. You will not find a replacement driver with this Re, fs, qts, Xmax and Vas. So i advice other drivers than the original Klipsch only with active crossovers and EQ.

If all fails, a good and cheap source getting new K-33 drivers is Audio Tuning in Vienna, Austria. They are authorisized Klipsch dealers. They sell this drivers cheaper than in Germany. I paid for each driver about 180 Euro incl. shipping. When desired i give you the contact information.

Bernd

[vwittke]

Hi Bernd,

I absolutely agree to you that the K33 is closely matched to the Klipsch Horns and that it is diffcult to replace it with an other type. This is the reason why I am concerned about the parameters of my drivers, FS 25HZ instead of 35Hz and qm much to low. I will build a test enclosure and see how it works. Please send me the contact information for Vienna Audio Tuning. Compared to the prices for used drivers on Ebay, 180E for new drivers looks quite reasonable. I intend to build the complete LS, for now i have 2 woofers, 2 unknown squawkers (said to be Belle Klipschs Drivers) , 2 ACR-copys of K400 and EV-Tweeters. I am looking for a pair of crossovers.

Thanks,

Volker

[BerndH]

You can build you crossovers either by the plans from Al Klappenberger, see http://www.alkeng.com/, or by the older style Type A network, see attached file.

About the differences between these crossovers and where to get the needed autotransformer see the thread "La Scala crossover upgrades-ALK network bass driver" in the 2-channel audio forum, http://forums.klipsch.com/idealbb/view.asp?topicID=26529&sessionID={479C99B3-9938-4A8A-AA0D-BC18068CC411}.

The adress of Audio Tuning is Audio Tuning, Margaretenstraße 98, A-1050 Wien. Ask for Mr. Bitzinger, phone 0043/1/544 85 82. This man will help you.

Bernd

[djk]

I modeled the response in the 40~70 hz range with the TS parameters provided and find the frequency response to be within ±1dB of each other. The mass corner for horn loading purposes is identical. I would use these drivers.

[vwittke]

Many thanks to everyone, I will use the drivers ! I was worried about fs because I heard such a lot about the exact matching of the K33-TSP and LS.

Volker