4430 acoustic wadding and x-over

[GlenD]

Hi
I am building a set of 4430 enclosures and would like a little assistance re the acoustic wadding used in side the box.
Is there a guide to the thickness and the weight per square meter?

I also plan to run and active crossover, crossing at 1kHz. Would you recommend still building in the horn x-over for the horn.
the x-over is 24db/octave .

Lastly mass rings, I read pros and cons, the drivers are E140 baskets reconed with aftermarket 2235 cones.

Any advice welcome.

Many thanks
Glen

[1audiohack]

Hi Glen!

Welcome to Lansing Heritage!

My 4430's have the JBL standard 1" thick yellow fiberglass on every inside surface but the front baffle. I don't know the density. I am going to pull the woffers from mine in the next week or two and I will pay more attention to whats inside.

Does your crossover have the capacity for EQ? There is a substantial amount of signal shaping in the stock networks, besides the actual crossover. The 2344 is easy to get to sound OK, but it takes some real work to make sound great. Dave Smith did a great job with these. Oh yeah, 1kHz is it.

Motors, mass rings, aftermarket come kits verses original, sounds like you are in for some experimentation here. I can tell you from direct experience that using an E motor and a JBL C8R2235 cone kit without a mass ring will give you between 5 and 6dB upward slope as compared to a proper 2235. If you have EQ in the chain this is easily delt with.

Bounce back and fill in some blanks and we'll help you along.

All the best,
Barry.

[GlenD]

Thanks Barry
I have L96s that have the yellow 1" fill, if it is the same I can measure to get the density.

My current plan is to machine up a set of mass rings, to get as close as possible to a 2235.
One comment has been people remove the mass rings to avoid then hitting the magnet pole and making a clang noise. Have you heard of this.
When I look at a mass ring it has a small lip that aligns the ring true to the voice coil former. On thought was to machine the ring with the lip such that the ring sits a little forward to provide more clearance.

Re the cross over, I was hoping to use an analogue one vs a DSP. I do have both (DBX drive unit). If I hit trouble, then plan B is to add the 4430 top end part of the cross over.

Thanks again
Glen


Hi Glen!

Welcome to Lansing Heritage!

My 4430's have the JBL standard 1" thick yellow fiberglass on every inside surface but the front baffle. I don't know the density. I am going to pull the woffers from mine in the next week or two and I will pay more attention to whats inside.

Does your crossover have the capacity for EQ? There is a substantial amount of signal shaping in the stock networks, besides the actual crossover. The 2344 is easy to get to sound OK, but it takes some real work to make sound great. Dave Smith did a great job with these. Oh yeah, 1kHz is it.

Motors, mass rings, aftermarket come kits verses original, sounds like you are in for some experimentation here. I can tell you from direct experience that using an E motor and a JBL C8R2235 cone kit without a mass ring will give you between 5 and 6dB upward slope as compared to a proper 2235. If you have EQ in the chain this is easily delt with.

Bounce back and fill in some blanks and we'll help you along.

All the best,
Barry.