Have you tried "doping" your speaker cones?

Twl, how could you do that ? What you did is both illegal and immoral. This is not to mention that you might have even gotten your drivers "hooked". For shame, for shame...

Actually, i've heard many positives about doing something like that. I can see how it could help in reducing cone break-up, flexing and distortion. As you mentioned, i think that it is most beneficial in the upper mids and treble.

Out of curiosity, does the driver that you are using have a whizzer cone and if you've done anything to work with that ? Sean
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Those are good pointers from Herman and Maxgain as to a source for "doping compound".

As to the whizzers, the reason that i asked is that i've heard of some people using high density foam tucked between the main cone and the whizzer. Basically the same approach you've mentioned but with even less mass.

Not only were they concerned about flexing of the whizzer, they also mentioned nearfield reflection between the main cone and the whizzer. I could see how this could happen and how it could distort the frequency response / radiation pattern to a large degree. Obviously, some frequencies would be more affected than others.

According to what i've read, using the high density foam not only stiffened and supported the whizzer, it would tend to absorb some of the higher frequencies that might have otherwise been distorted. This should result in a measurably more linear response without affecting driver speed to any noticeable degree ( much like light doping ). I just wondered if you had any personal experience with a similar approach.

The reason that i ask is that my brother had attempted to build a full range TL ( transmission line ) using a Pioneer 8" with a whizzer. It was his first attempt at a TL and as such, he tried to make it "bigger and better" in every way imaginable. Needless to say, the initial results were not what he had hoped for, but we had both learned a lot along the way. We have since found out quite a bit about the specific driver and its' characteristics from other "full range tweakers" that have experimented with that model. From what i've seen, they've gotten pretty good results out of it but it did take a lot of work, measurements and tweaking.

Given the cost of the drivers ( not much at all ), i think that doping them is in order. This should at least help with the upper midrange "brittle-ness" that i noticed. Playing with damping on the rear of the whizzer cone also seems like a logical approach and may help tame other related problems. We might be able to salvage the original cabinets, but i'm not sure. He built them like a tank ( screwed and glued ) as if it was a final design rather than starting off with a basepoint and going from there. As one learns as they get older ( and hopefully wiser ), youthful enthusiasm has its drawbacks : ) Sean
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Thanks for the clarification Will. Sean
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Herman, no need to apologize. You put forth what you thought was helpful information. Luckily, someone else caught it and was able to correct it. When we are too big to make mistakes or be corrected, THEN we need to start thinking about apologizing : )

Twl, sounds like you've just had an "audio revelation". It's great, isn't it ??? : )

You're finally hearing what a point source can do. Now if you could only get rid of the boxes and start doing some 360* radiation, you'd really see what width and depth was like. When things really start to cook, you'll take notice of image height too : ) Sean
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PS... Sometimes I have to silently laugh when people ( primarily salespeople ) talk about the "depth" of the soundstage on a system. I think that you may start doing the same.