9844 overhaul project. Advice welcomed!!

[grasshopper]

Out of respect for the original poster in this thread:

http://www.hostboard.com/cgi-bin/ult.../f/3729/t/2341

I decided not to hijack any further and continue the great conversation and flow of advice on to a dedicated thread. This may also provide help for anyone else looking to tackle a complete rebuild of 9844 and/or 9846 type monitors. I'll provide links to pics once I really tear in to it.

The 811 horn definately sounds like a tuning fork (cow bell- love that description) at higher volume levels and I wonder if mounting them on TOP (outside) of the new cabinets (like VOTT) would help. It might (at the very least) isolate it from the mechanical distortion caused by the vicious action of the 2X12's. I thought about using a self adhesive sound dampening material to help as well. Opinions??

There's no question about the quality of sound at nominal levels. That's the best damned 1" compression driver/horn combo I've ever heard. Hours of listening without ear fatigue. Who would have known? So..tell me again why the recording industry moved to an all cone standard!?


Also. What do you guys think about adding an isolation wall in the main cabinet to create independent chambers for the 12's? They act like a quasi passive radiator and it might tighten up the low end a bit. It could also destroy the overall low end extension and I certainly don't want to screw THAT up!

As far as biamping- I'm curious. After shelling out the bucks for boutique paper oil caps I wondered what the **** I was doing! It's not too late as I still have the other pair of 9844's waiting in the wings. Factory has them crossed over at 800Hz. I have some decent amps that would be more than up to the task but I don't know how to protect my drivers. I'm new to this sort of thing and I always hear the horror stories about how some guy blows his beautiful speakers up when he uses active crossovers.

[Art J.]

As far as the ringing goes,

When I rebuilt my 9846's, I noticed a square outline on the
horn where there was some kind of damping block that rotted
away. I replaced it with a bar of Duct Seal as shown in the
picture below.

Duct seal is heavy, cheap and very effective. You can easily
remove it too. You just cut away the bottom plastic and stick
the whole bar on. I think it would be less effective if you spread
it out as sound needs "mass" to be absorbed. (home depot has it)
Use as many bars as you want. Makes the horn very dead.

http://xs104.xs.to/xs104/06321/ductseal.JPG


.................................................. ...................................

"Doctor, Doctor!, My horn rings like a bell
when I hit it like this!"
Doctor : "Well then, Don't hit it like that"

.................................................. ................................

[grasshopper]

My 25 cents worth, adjusted for current gas prices

I hear ya! I remember when it was only 2 cents and cigs only cost $8 a pack!!

Alright- I guess I'm ready for the table saw. A buddy of mine suggested putting in a removable center baffle so that if I didn't like the response I could simply remove it. I think I'll do that. I may have to retune/report the drivers though...

If I can get that horn to stop ringing - I think I'll have a real winner. I was just listening to them hooked up to a pair of SET tubes and they are real champs. Can't wait to her what they sound like when I'm done.

Thanks for all the help guys. I'll keep you posted on the process and results. Nice site!

'hopper.

[Art J.]

Hello Grasshopper, What is wrong with the bass that makes you
want to use a divider?
The Altec design uses the ratio between driver resonance (fs),
cabinet volume, and port size to achieve tuning.
You will lose all your bass with a divider.

[grasshopper]

Art J.

That's the response I was fishing for. Thank you.

The low end these things produce is astonishing and it puts a big grin on my face regularly. It does seem a bit "smeared" when asked to do the quicker stuff. My source components are pretty good so I don't blame them. It's probably just that cabinet flexing and coloring the performance of those 414's.

I'll stick with the original cabinet design but make the panels thicker.

[Old Guy]

Threads mutate on a regular basis here.

You got some good advice on damping the horns.

Most modern designers prefer a seperate chamber for each woofer.

As far as caps, there are inherent problems in any cap. No matter how good. Biamping eliminates those problems.

My 25 cents worth, adjusted for current gas prices.