Altec 604-16X Crossover Design

[MANZANITA]

Hello Jeff;

Thanks for sharing your findings. Very professional and detailed as always!

I did not like the sound of the 16X very much and sent the pair to GPA to have them converted to 604-8k formt. Much improved. Much easier to work with.

Are you considering re-doing the 16X or using them in stock trim?

[donaldpatten]

Jeff:
I have a preliminary set of component values for a low pass filter with about 0.22 msec delay and a crossover of 1550 Hz. The design uses three coils in series, three shunt caps plus a Zobel.The Zobel I use is as 15 ohm resistor and 16.7 uFd to flatten the woofer impedance to 13 Ohms (500 Hz - 3kHz). The coils are : L1 = 1.64mH ,L2 = 0.88mH ,L3 = 0.41mH. The caps are : C1=6.61uFd , C2=3.89uFd , C3=0.824uFd. For the coils I use #18 awg for L1 & L2. And #15 awg or two #18s bifilar wound for the last coil.
Try it with your hi pass section and check the acoustic pulse response. Lett me know if I should adjust any values.
Don

[jmarkwart]

MANZANITA,

I haven't decided whether to re-do the 16X into an 8K, or try it as is. The only way the 8K conversion would make sense to me is if both drivers come out as better performers in the 1-2kHz region. As you know, they leave a bit to be desired in the stock config. The 16X is a difficult duplex to try and build a simple and elegant crossover for. Thanks for your input on the conversion at GPA.


Don,

Thanks for the .22ms delay values. I built a CALSOD model of the 16X and its filter using your LP delay and zobel filter combined with my HP filter. I got a good combined phase response at 1600-1700Hz with the acoustic phase of the HF reversed, but wound up with too much combined SPL magnitude around 2K. I had been able to avoid this with the spread Butterworth by letting CALSOD optimize the component values to achieve both a target SPL and desired filter response for the woofer. I may try this same technique with your LP filter and see what happens to the delay. I'll let you know, thanks.

Jeff

[jmarkwart]

Hi All,

I just finished a passive crossover design exercise for the Altec 604-16X, one of the early ferrite duplexes that Altec only sold without a crossover. If you have a pair lying around you want to put to use, take a look at http://home.earthlink.net/~jmarkwart/id16.html

Jeff Markwart

[donaldpatten]

Jeff
try these #
L1 1.60017 mH
C2 6.466307692 uF
L3 0.85943 mH
C4 3.800923077 uF
L5 0.4004 mH
C6 0.805538462 uF
Don

[donaldpatten]

Jeff
The LP filter is very sensitive to load impedance. If it is off the design (13+-1) the delay goes wild. I suggest you let the woofer sing and notch the horn.
Don