altec 414/comp driver crossover

[stuck.wilson]

hey all--

looking to see if anybody out there has got experience with an altec 414 8ohm (b in this instance), and a passive XO centered somewheres around 1k- first or second order is fine. really, what i need is to find impedance curves to try to extrapolate what precisely is going on- in theory- with my crossover at xo frequency.

no impedance info for one driver.. no idea what the real crossover freq. is!

i've only got sonics to rely on- and despite being happy with the midrange- i'd still like to see if theres room for improvement.

currently, the driver is in a 3.6 cu ft. ported box tuned to 32hz.

the present layout of the crossover is-

bms 4552nd-- 16.8 uF main cap- lpad- 5uF compensation cap across postive terminals of the lpad (for horn rolloff)

altec 414 8b- 1.2 mH inductor.

what i THINK is going on: BMS at 1080 hz crossover- 9.25 ohms.
altec at same- at 8 ohms

BUT- is the altec stable at 8 ohms at crossover for a box of this size?

thanks for any input!

yrs
d.

[moamps]

Hi:

In the picture below you may find the impedance/phase graph of an Altec 414/8 I messed with a while back. I think you may need a measurement microphone and some software to be able to tune the system properly.

Regards,
Milan

[stuck.wilson]

mo!

that's EXACTLY what i was looking for! what sized cabinet did you measure this in?

you are the man!

d.

[moamps]

If my memory serves me correctly, I believe it was a free-field measurement of TS parameters, no box.

Regards,
Milan

[stuck.wilson]

hey mo or other passive users--

with a driver running 4 ohms over nominal at XO-- what would be the ramifications for a 1st order's inductor? by the looks of it-- it brings the value up to 1.8mh or thereabouts for a similar frequency-- but i'm not sure how to calculate an inductor's value in this instance-- is it based on the crossover impedance, the nominal, or some sort of average of the two?

any ideas?

thanks much!

d.