I did somewhere, I may have deleted them off my flickr account but pretty sure I have them at home, will post up tomorrow as I am at work right now.
http://www.flickr.com/photos/82812412@N03/7902706654/
Nice curves. I was surprised that the low freq Z peak was so high (in freq).
My 605s were 22 Hz when new and a year later around 30 Hz.
Please add a Zobel R & C and rerun the curves. I calculate Rz= 11.1 (25 // 20) and Cz= 10.7 (8.2 // 2.5) .
I can send you the parts , PM me.
I think I only had my sweeps starting at 30Hz, Don. I should probably start at 10. PM sent...Originally Posted by donaldpatten
CRADELDORF
Nice curves. I was surprised that the low freq Z peak was so high (in freq).*
My 605s were 22 Hz when new and a year later around 30 Hz.
Please add a Zobel R & C and rerun the curves. I calculate Rz= 11.1 (25 // 20) and Cz= 10.7 (8.2 // 2.5) .
I can send you the parts , PM me.
The DATS curves you posted from Flicker, were they free air? Say with the speaker hung on a rope from a sky hook ...
The low freq peak IMHO , should be in the 30 Hz ball park not 54.
Last edited by donaldpatten; June 15th, 2013 at 12:11 PM.
The 604D has a published 40 Hz Fs, so 54 Hz seems reasonable for such an old driver. The 605 series replacement had a 25 Hz published Fs, which carried over into the 604E when this series was reinstated.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
GM
Thank you for your input .
You wouldn't recall what Fs spec was for the 604C ?
Don
You're welcome! AFAIK, all the early horn loaded duplexes till the E had around a 40 Hz free air Fs [Fsa], though I've seen postings that the original was around 60 Hz, but I'm pretty sure that was its in-cab tuning [Fsb] based on reverse engineering some early cabs since the pioneers decreed that a sealed cab that raised Fsa by 1.56x would yield an extra 1/2 octave of flat response when reflex tuned to Fs.
GM
Loud is Beautiful if it's Clean! As always though, the usual disclaimers apply to this post's contents.
alancohen
The curves you did in #59, were dB SPL. To do Impedance curves you need to plot the voltage across the XO input, with the speaker connected to the XO.
First connect a 1k Ohm series resistor between the power amp hot output and the XO input. Connect the speaker com. to the amp common.
Plot the voltage across the XO input. To calibrate your test ckt, sub a resistor for the XO and speaker. I like to do calibration resistors for 8, 10, & 16 Ohms . If you can, change the vert scale from log to lin.
see the Lansing form .
Don
Hi Don, It was taken free air but not hanging. It was standing on end on shag carpet balancing on a 4" long piece of 6" pvc pipe.
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