K-57-K sensitivity rating and CW2 Xover ?

[DrTUBE]

Hello,

Anyone knows the sensitivity of the K-57-K squawker as used in the CW2 (resin-molded K-601 horn version) ?

In this forum, I read that it is + 3dB louder than the K-55, and also read that it has the same sensitivity as the K-55...

Moreover, can I have a copy of the CW2 Xover schematic ?

[BEC]

The K-57-K has about the same output as the K-55. This only applies to frequencies above 600 hz. The K-57 falls off rapidly below 600 hz where the K-55 goes on below 400 hz.

Attached is a copy of the CII crossover schematic.

Bob Crites

[DrTUBE]

Thanks Bob for the useful information. By the way, I tested the K-57 and also found the rapid falling below 600Hz - so I wonder if it is not responsible of a little "horny-duck" sound of the K-57 on male voice for example. Do you think that a K-55 would do better ?

[BEC]

If it is in a Cornwall II, you are not using it below 600 hz anyway, so should not really make much difference. Also, you would have to use a different horn for the K-55 since the one in the Cornwall II bolts on to the driver and the K-55 is a screw on driver.

Bob

[DrTUBE]

In fact, my CW is a DIY proto (K-792-KP, K-57-K, CW1526C 15", AT-1) on which I experiment before final version. Nonetheless, the K-57 has difficulties to extend to 600Hz, as you can see it on my (I hope enclosed here) free-air response and, reading you advice, I suppose that the K-55 won't do much better, mainly because the horn size remains the same. And, in addition, I will have to correct the so-called-supposed default around 9KHz which doesn't exists with the K-57.

But looking closely to the CW2 Xover schematic you've enclosed, I notice that the 3507 T-8A give -8dB attenuation to the K-57, instead of the -6dB found with the K-55 on other B Xovers fitted with the 3110A T-2A : this detail may be the cause of the "horny" sound of my K-57, by excess of level, because connected in the K-55 + T-2A way on my DIY CW Xover.

Thanks for input, Bob.

[BEC]

Klipsch used the same driver as the K-57 (the K-52-H) on a screw on horn in the last years of the Cornwall 1 with the B-3 crossover. In that crossover, the attenuation was also 6 db just like the K-55 was attenuated. Anyway, I don't see much difference between the K-55V and the K-57-K above 600 hz.

Here is my trace of a K-52-H on a K-400 horn.

Bob Crites

[BEC]

And K-55V single piece phase plug.

Bob Crites

[DrTUBE]

Your curves speaks for itself : I see the difference between the K-57 and K-55 on the K400, and I can mentally transpose them with a shorter K600/601 horn : the K-55 would reach a bit more linearly the 600Hz zone than the K-57, but I wonder if the shift is worth... Nonetheless, the CW1526C shows a good linearity until 600/700Hz when tested alone in my CW box, but when filtered, the result is altered, so I have to re-work on my Xover first...

For info, here is a Xover comparison, near field (port not considered), sinus sweep, between : 1 - the CW1526C unfiltered / 2 - with a 3mH 0.07ohm 6dB/oct like B style / 3 - 3mH+22uF 12dB/oct 600Hz / 4 - 3mH+22uF 12dB/oct like B3 style, showing this alteration which directed me to look at the bass extension of the squawker.

Thanks for your support, Bob.

[WMcD]

Dr. Tube,

Thanks for that Lsp curve.

I'm always interested in the horn/driver response above 6 kHz. Your curve shows the issue.

The VTV article on the K-Horn stated that it was the cause of a "shouty" horn sound and a filter, the "P-Trap" removed it.

Best,

Wm McD.

[DrTUBE]

Hello Wm McD,

Care : unlike Bob's, my responses are for a K57+K601, not for K55+K400. Nonetheless, What is the "P-trap" you are speaking ? Have you got more info ? I Know nothing about that except its name, and I suppose that it applies to the K55+K400 but it may be of some interest to me for a K57+K601 application.

If you are interested, I have other traces (response, impedance) about my DIY CW and its speakers : if it can help... I am searching by myself, taking in count informations coming from other users.

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