9844 Information?

[leifchristensen]

hello
I have just gotten hold of a pair of 9844-8Bs, that I?ve installed in my oldest son?s room;
do you want me to take measures?
If so,list which ones you need and I?ll try to do it in a couple of days
best
Leif
Norway

[GM]

........they're all in the same box/same porting.

Herein lies the crux of the matter for me, I've seen four different porting schemes, so which goes with each model and woofer combo?

horn-in-reflex vent
center vertical slot
vertical slots between each woofer/side wall
ducted ports in upper corners

Then there's the issue of driver offset with at least three versions:

recessed for reflex vent
flange flush front mounted
recessed flange front mounted

Last, but not least, the horn placement will in theory affect the XO to achieve the same horn down angle projection, so which XO goes with each?

This then begs the question of how much, if any, the horn's acoustic center changes when switching to the 900 series drivers, i.e. what is the measured acoustic distance at the XO point between different small format drivers when properly mounted on an 811?

WRT using the M19's XO, in theory it would affect the 9844's polar response enough to make it a questionable match through the critical speech BW to the M19s if sitting much off axis due to the differing horizontal power (polar) responses of tandem 12" Vs a single 15".

Regardless, for HIFI/HT apps, best IME to tune to meet the needs of the app rather than arbitrarily using a factory tuning designed for a different specific app and now that digital XOs, time delay and EQ is price competitive with the parts cost of a pair of good passive XOs I see no good reason to bother dealing passively with these other potentially daunting issues.

GM

[Carl Bill]

GM.... did Altec actually manufacture that many variants of the 9844? Vents ect?

The Model 19 has the 811 placed farther back from the front baffle than the 416. I noticed that the 9844 has the 414's placed 3/4" farther back than the 811. Can I assume this is to possibly align the voice coils?

I was hoping to use a NOS Model 19 crossover. But it appears that this may not be optimal. I suppose I can try it and see how it sounds...

Thanks for all the information.

[GM]

You're welcome!

Well, I've seen each variant, but in retrospect, some could have been customs since the local distributor had their own in-house design team and they typically would paint/decal them to look 'factory' if a utility cab was spec'd.

Right, though the 9844's odd offset was done to get the downward tilt to the horn's acoustic axis whereas the M19's was probably to make it the same as the woofers, so its XO probably won't be anywhere near optimum even if you get offset right since it's optimized for the 416, not dual 414s.

GM

[GM]

hello
I have just gotten hold of a pair of 9844-8Bs, that I?ve installed in my oldest son?s room;
do you want me to take measures?
If so,list which ones you need and I?ll try to do it in a couple of days
best
Leif
Norway

Greets!

Is it like this one?: http://www.lansingheritage.org/image...closures19.jpg

GM

[leifchristensen]

no I think it had 2 round ports above each other between the woofers
but I can check?
best
Leif

[GM]

no I think it had 2 round ports above each other between the woofers
but I can check?
best
Leif

Sheesh! Yet another variation. Yes, please document the particulars as best you can WRT inside dimensions, horn mounting, vent system details.

GM

[leifchristensen]

ok will do first weekend
best
Leif