416-8B

[acre]

Hi all. My next project is to build some home cabinets for a friend who has the A7-500's in his living room. He wants a domestic enclosure for the 416-8B LF drivers. I know I should measure the T/S parameters for each of his drivers but is there a generic set of parameters I can use to model these in Bass Box Pro? I loaded them from the BB Pro database but there seems to be a lot of red radio buttons beside some of these parameters, indicating that they are really not too reliable. Thanks....Lee

[GM]

Well, there's these, but with old AlNiCo motors that's never been re-zapped, its Qts can potentially be much higher, making the cab acoustically too small and tuned too high: http://alteclansingunofficial.nlenet...ele-Small.html

Also, if driven with a high output impedance, then this must be factored in also as it effectively raises Qts.

GM

[acre]

Thanks GM! Good question about the Qts. This system will be run with a very good 12" sub, strictly for living room use. I assume if the cab is too small or the tuning is a bit high, the sub will take up the slack? Also, is there a reliable Le number I can use? Thanks....Lee

[GM]

You're welcome!

Measured Le I have varies from ~1 - 1.5 mH/1 kHz, but some are re-cones, while others are old..........

If the cab is too small and/or tuned too high, then there will be a hump in its response that can't be compensated for by adjusting the sub's XO point/slope, so if it were me I'd put it in the Altec recommended 7.5 ft^3 sealed alignment since it would be large enough and allow an easy blend to the sub even factoring in the vagaries of differing specs.

GM

[acre]

Once again, thanks GM. So by sealed alignment I assume you mean a sealed box. Bass Box Pro does show a recommendation of either sealed or vented with that particular driver......Lee

[GM]

You're welcome!

Yes, I didn't bother to figure out what the alignment's Qtc is due to all the variables in this case, just chose Altec's default recommended sealed box size for this driver.

GM

[bfish]

I came across an old Altec Tech Letter (267C, from 1987) that lists measured and averaged T/S data for a number of drivers. The 416-8B differs from the libray data in the Qts column, being listed as 0.28 instead of 0.32.

[GM]

FWIW, mine and some other's measurements are all around 0.3 Qts, though one person recently measured some at ~0.19 Qts! with a Woofer Tester 3 (a normally accurate set-up), so not sure what the deal is since the 416 motor isn't strong enough to go this low with any Altec re-cone kit AFAIK.

GM