Altec 406 - 8Y

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OK, got my memory refreshed and the 406 is a 10" variant of the 12" 414B, i.e. has a 414 motor with Y = no pot, C = pot and a [NLA] special two stage curvilinear diaphragm; factor in that it's designed to drive a heavy phase inverter [AKA passive radiator] in the Bolero it seems reasonable that Fs, Qts will be similar and once again 'lucking up' in a quick Google image search found this to be true.

Response and basic T/S measurements of a 406-Y:

GM
 

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I've got a pair from the Altec 890C Bolero. I'll try and pull them and take them to a local speaker guy Jamac, and see if he can measure the T/S parameters. Always wanted to, those are a really unique 10 inch woofer; with the 12" 414 woofer's 3" VC & Alnico motor. They sound like a big Altec, nothing else that size comes close.

Will get back later.
 
In the opinion of the readers of these posts, what would be the optimal type/size of box for these drivers? Why?

What about open baffle?

You're welcome!

Well, T/S specs says too low a Qts [< 0.312] for optimal venting, hence the PR, unless driven with a high output impedance to raise it [Qts'], so ideally would be in a large compression horn.

OB will work of course, though needs a helper woofer to fill in below its upper mass corner [fhm].

fhm = 2*Fs/Qts'

Qts' = Qts + any added series resistance: http://www.mh-audio.nl/newqts.asp

What I do, recommend for these type specs is a mass loaded [vented] TL = MLTL where net volume [Vb] = Vas, tuning [Fb] = Fs, which uses a TL to mass load the vent, improving the mid-bass some and allowing extension down to Fs, a real plus if driven with a high output impedance, so......

What are you going to use up high and assuming these will be used in a HIFI app, your average seated hear height or whatever height you want the HF at and I'll come up with a cab design.

GM
 
You're welcome!

Well, T/S specs says too low a Qts [< 0.312] for optimal venting, hence the PR, unless driven with a high output impedance to raise it [Qts'], so ideally would be in a large compression horn.

OB will work of course, though needs a helper woofer to fill in below its upper mass corner [fhm].

fhm = 2*Fs/Qts'

Qts' = Qts + any added series resistance: http://www.mh-audio.nl/newqts.asp

What I do, recommend for these type specs is a mass loaded [vented] TL = MLTL where net volume [Vb] = Vas, tuning [Fb] = Fs, which uses a TL to mass load the vent, improving the mid-bass some and allowing extension down to Fs, a real plus if driven with a high output impedance, so......

What are you going to use up high and assuming these will be used in a HIFI app, your average seated hear height or whatever height you want the HF at and I'll come up with a cab design.

GM

Thanks again GM.

Yes, these would be for hi-fi, but I don't know what tweeter to use nor what height the tweeter ought to be. I've been thinking about this for awhile but have only cursory knowledge of speaker building. Maybe my goals are a bit unrealistic... and really not worth the trouble.

Anyway, this is what I've been thinking:

The drivers are mounted in Bolero 890-C cabinets with original horn tweeters. They are lying on their sides on bookselves with tweeters at 45 inches.

I like the sound of the speakers very much but wondering if more can be gotten from the 406... I'd like to get lower bass out of drivers, better transients, cleaner mid-range, more detailed high end (the original Heppner horns are just ok).

I have some various tweeters hanging around including a couple sets of Janszen 130U electrostatic tweeters. But, maybe the 406 would not blend well with them? Maybe they're made to go with horns only? Maybe the 2000hz crossover is not ideal?

All these questions! Is it not worth it?

Finally, when you say "driven with a high output impedence" what exactly do you mean? Non-tube?

Thanks again,
Jeff
 
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