Exciting new line of fullrange drivers from Feastrex

[GM]

Originally posted by Scottmoose
...Welcome back Dave.

Where's he been? I figured his absence was 'Enabling' related.

GM

[Scottmoose]

I'd rather drink the wine than look at it.

Strange -as GM says, there shouldn't be enough grunt from a small unit to start exciting things -especially in a small box. If it worries you, mass loading the top with granite or marble chopping block should sort that out.

Originally posted by GM


Where's he been? I figured his absence was 'Enabling' related.

GM

I think it was one of his road trips, but don't hold me to that. Dave?

[kmaier]

GM, Scott,

Yes, I was also somewhat surprised that the wine had any rippling.... and I'm only using a 2-watt 45 amp (okay, so it puts out a solid 2.25 watts). Not sure if it was a massive glass... just normal for a good red... and besides, I didn't leave it there, a temporary parking place while swapping media. Still, the BVR is a nice sounding enclosure for the D5nf. I'm tempted to build the updated version (has the driver at the top of the baffle board) but living in Germany for the rest of the year sorta prevents me from doing much audio work until 2009.... sigh.

Regards, KM

[GM]

Understood. Try mass loading the cab as Scott suggests and if that doesn't solve the 'problem', then if you have large enough clamps, try the test again with the mouths under mild compression with/without mass loading.

GM

[kmaier]

Yes, I'm going to try and work on a couple audio projects when I'm back in the US end of September (mainly building my 2A3 amps) but will also try some mods to the BVRs as well. Here's a pic of the upper chamber showing the bracing:



It's pretty stout in general, but I'm going to try adding some vertical braces from the rear brace of the driver to the top and bottom of the chamber. I'm starting to worry about loosing too much cubic space however.

Regards, KM

[Phil Townsend]

Nice Box KM!!!

[planet10]

Originally posted by GM


Where's he been? I figured his absence was 'Enabling' related.

GM

Besides just been really busy, i did just get back from a trip to Calgary -- driving thru the Rockies during sunrise is sure spectacular.

dave

[cdwitmer]

This message just in from a happy builder of the new standard Feastrex box for his D5nf drivers:

"I don't know what 'method' Feastrex used to come up with their new standard enclosure but they have managed to create a true 'full range' enclosure (i.e., flat to 50Hz) with no need for baffle step compensation, which in my mind is no small feat. For me, it makes the difference between being able to use a 2W SET amplifier or having to forego that for a more powerful amp. (I would do the correction at line level.) Of course -- assuming all other things are equal -- the overall SQ is going to be better if you can avoid BSC in the first place, although obviously there are situations where the trade-offs are worth it. Now I'm wondering what might happen if I experimented with a similar enclosure for my Lowther drivers too . . . "

My comment: I think a lot of it may have to do with the driver. I suspect the rising frequency response curves of many fullrange drivers tends to exacerbate the need for BSC, so the relatively flatter response curve of the Feastrex drivers gives them an advantage in that regard. (That's just my guess, of course. Maybe the enclosures are doing something special too, but I'm inclined to think most of it owes to the drivers themselves. In any case, I'm glad we've been able to add another happy camper to the list of Feastrex enclosure builders.)

-- Chris

[cdwitmer]

A while back I translated and posted the basic approach to enclosure design that one Japanese fellow had been using -- apparently sort of a modification of the approach taken by the late Tetsuo Nagaoka.

Well, for better or worse, his first attempt was a big disappointment.

He went back to the drawing board and came up with these:



Those were "close but no cigar." The bass was quite impressive.

Now I hear he has made some changes to the above design and is really thrilled with the results that he is getting. So it seems we are close to getting another design done.

He's working with the D5e-I, so it may be of limited usefulness to D5nf owners. Anyway, I'll keep you posted . . .

-- Chris

[cdwitmer]

Finally, for all you folks who have been on a hunger strike until you get your numbers, a little bird tells me that Clark Blumenstein has been quite pleasantly surprised by what his preliminary measurements are telling him about the D9e-I fitted with the new spiders. I think it would be prudent to check to make sure everything is kosher in the way that equipment is being used, but there are some very interesting implications for all drivers that use the new spiders . . .

Sorry if this only makes y'all hungrier than ever. Maybe you can pound the table harder and chant louder . . .

-- Chris