4.5" vs 6.5" Trade offs

[Kensai]

Only drivers I can make direct comparisons between would be the Pioneer A11 4.5" and B20 8". I found the forwardness of the smaller driver to be troubling compared to the easy listening of the larger driver.

Some caveats here, since these aren't Fostex. I think that the larger whizzer on the B20 helps produce a smoother midrange than the smaller whizzers on say the FE16x and FE20x series. On the other hand, the smaller Fostex whizzers quite obviously reproduce HF better. I can get the HF I want out of the B20 with EQ, but this is no way to build a generalized sound system. I'd not be able to get adequate HF performance out of them if they weren't in my office rig where the sound card can very precisely EQ them, so for a less specialized listening setup, they would require supertweeters.

Funny thing with the A11s, though they seemed to have more HF response, when running tone sweeps, it became obvious that they rolled off a smidge earlier than the B20s up top. I didn't feel much urge to EQ their top end while I had them in the office, and now that they're driving inverted BiBs in my buddy's living room, he things they sound perfect, better than anything else he's ever heard (okay, I admit, he's no audiophile, what can I say). The forward balance, though, seems to play right into his use, basically replacing his TV's speakers, mainly for HT duty, so this sort of balance (peaky mids and extended bass from the cabinets) gives dynamics and clarity to dialog.

Take that for whatever its worth. I think that alot of the "magic" that the smaller drivers get attributed with has something to do with being able to do FR with more top end without whizzer cones, removing one last crossover from the system (the mechanical one between main cone and whizzer). I think the A11s would benefit from phase plugs and some doping mods (puzzle coat and EnABL), but that would make them at least $60-$70 drivers rather than $10, and they would then just be competitive with similar sized Fostex without mods, so then you're forced to compare lots of disparate driver at various degrees of modification. I mean, my B20s are now fully P10 treated, phase plugs, puzzle coat, EnABL, and I bet that Dave would have to charge in the $125-$150 each for these nominally $25 drivers to cover the labor involved (whizzer cones are evil for EnABL modders; don't say you were never warned). They're so good now that they've brought into question everything upstream in my chain. Just makes me wonder what happens when you start from higher quality stock units, since the costs in materials and time can't possibly be any higher.

What I wish I had budget to check into is how would say FE208sig or FF225K sound compared to the B20 since they all would need some HF assist, and those Fostex have no whizzers . . .

Kensai

[planet10]

Originally posted by Kensai
I mean, my B20s are now fully P10 treated, phase plugs, puzzle coat, EnABL, and I bet that Dave would have to charge in the $125-$150 each for these nominally $25 drivers to cover the labor involved (whizzer cones are evil for EnABL modders; don't say you were never warned). They're so good now that they've brought into question everything upstream in my chain. Just makes me wonder what happens when you start from higher quality stock units, since the costs in materials and time can't possibly be any higher.

Before doing yours i felt that if i could sell them for $275/pr all done up with a phase mounted tweeter i might have something. After doing yours i realized it would have to be more (so i abandoned the idea) ... i will be exploring the phase plug with tweeter option.

dave

[Kensai]

Dang, Dave . . . so FE20x drivers are that much easier to mod? What would those run once you've got them into production?

Kensai

[chrisb]

Originally posted by Kensai
Dang, Dave . . . so FE20x drivers are that much easier to mod? What would those run once you've got them into production?

Kensai

I think his reference for the Pioneers was including dust-cap / coaxial tweeter surgery, in addition to the EnABL etc. All very time consuming, and not something that you'd want to entrust to a (poorly trained) 12 yr old.

Arguably, cone / basket treatments for the drivers themselves would require comparable skill levels and time investment.

Additionally, I'd imagine that anyone desiring extended HF performance when using one of the 8" Fostex drivers, would probably be considering at the very least something like the FT17H, etc.; these larger horn tweeters don't lend themselves to coaxial mounting.

[planet10]

Originally posted by Kensai
. . . so FE20x drivers are that much easier to mod? What would those run once you've got them into production?

Yes. Under the whizzer on a 20x isn't that hard once you have learned the trick. That they are white cones makes it easier too (as you can see what you are doing). 16x are another matter.

Retail on FE20x will need to be a bit north of $400/pr, The primary purpose of current R&D pairs is to see if i can get a consensus of whether they will be worth that.

dave