BetsyK- Enclosure for Imaging/Staging

[NcHalfrican]

I currently have my BetsyK's in a pair of BiB's. I'm looking for better imaging/staging and was wondering if y'all had some enclosure suggestions.

 

[pjanda1]

Before you give up on the boxes, I'd try a couple of things. Imaging can be a challenge with BIBs for a couple of reasons. Midrange can get through the single fold without too much difficulty. You might try shoving a bunch of stuffing into the mouths. By a bunch, I'd think 3 pounds per side. If you don't already, I'd put a couple of pounds in the bottom too. The corner placement BIBs demand isn't ideal for imaging. Try over-toeing them so the axis cross in front of you. That will keep the treble farther from the side walls.

Paul
Wild Burro Audio Labs - DIY Full Range Speakers

 

[NcHalfrican]

I currently have about half a pound in the throat and a pound and a half in the bottom, guess I'll try adding my remaining pound into the mouth. What do you mean by over-toeing? What enclosure has given you the best results as far as imaging goes. I'm in the mood to build, haha.

 

[pjanda1]

You need a great deal more stuffing to make any difference. You might even consider some loose weave cloth over the mouths. By over-toe, I mean so that the left speaker points to the right of your right shoulder and vice versa. I usually have the center axis crossing a foot or two in front of me.

Imaging with fullrangers, especially larger ones, is different from other speakers. Something like the Simple TL out in a room would probably be best, but you might want BSC. As a quick experiment, I suggest you knock up some OBs. Use series resistance (really small wire or low ohm, high watt resistors) to get the Q up high enough. OBs image very differently. If you like it, you might consider a more complicated setup.

Paul
Wild Burro Audio Labs - DIY Full Range Speakers

 

[natehansen66]

Hey Paul, not to cut in, but would raising the Q on my K's like you suggest give them a little more bottom end? They fall off at about 320 hz on my narrow baffles, which by the way image beautifully!

I would also suggest ob's for imaging......I found the narrower the better but then you're fighting the dipole rolloff...........

 

[NcHalfrican]

I added some pillows(currently out of acoustic stuffing) to the mouth of the BiB's, as well as over-toeing them. The stage seemed to widen and become a bit more detailed I still want to try some new boxes, though What's a BSC? What size wire would you recommend to achieve the desired Q?

 

[pjanda1]

Nate, it is pretty tough to deal with really narrow baffles. I think if you raise the Q more, you'll get a hump around 100-150hz and still too little in the 200's. You could probably simulate it in the various OB simulators. But you either need a wider baffle or woofers run up higher. OBs need to be big. Period.


Nc, cut the pillows open! Raising the effective Q is to use the BetsyKs in OBs (basically making them behave like Betsys). You don't want to use tiny wire with the BIBs. BSC is baffle step compensation. Most boxes need it when placed out into the room. A quick search will tell you all you need. Of course, some folks like the forward midrange that results when you don't use BSC.

Paul
Wild Burro Audio Labs - DIY Full Range Speakers

 

[NcHalfrican]

But what size wires would I need to use if I wanted to do some OB testing? Ah, ok!

 

[pjanda1]

If you've got a solid state amp, and your cable runs aren't super long (the normal 8 ft or so), I'd try as small as 36g. I think radio shack sells a kit with multiple sizes of magnet wire. It should make for cheap experimentation.

Paul

 

[NcHalfrican]

Wow, that's mighty small. Thanks for the all the help! I'll post up some results when I can

 

[glt]

Anyone with an "optimal" BIB design for BetsyK? (No constrains in dimensions).

 

[pjanda1]

For a no-holds-barred approach, I'd use GMs formula, which is the same thing the spreadsheet uses.

Paul
Wild Burro Audio Labs - DIY Full Range Speakers