New Box Idea (Life after BIB's)

[rjbond3rd]

Oops, I stand corrected -- apparently HornResp can model MLTL's. My apologies:

http://www.diyaudio.com/forums/showt...50#post1854550

[Godzilla]

http://homepage.mac.com/tlinespeaker...7-MLV-0v99.gif

The Meliva was the box i was thinking of... has one been developed for the Fostex 165/6/7/8? LOL

>>> symmetrical ports above and below the driver

If you like ports on top and bottom maybe you can re jigger and create a one off Meliva style box.

[planet10]

Come on Jeff... 1st spelling, Mileva, 2nd, it is for the FE127. Demetri is for FE207e (FE167 can be used, but Fonken167 is better for that driver.

How are FF165KeN auditions going?

dave

[pjanda1]

To my very untrained eye, Horn Response seems to factor in some quarter wave action, but not nearly to the extent that MJK's sheets do. It is more than likely that I don't know what I'm doing though.

Jeff, I'm also considering doing an OB setup similar to the Betsy +Boomer. I've got plenty of amplification, so I'd probably use a cheap proaudio crossover (for the woofers) driven by a voltage divider on the outputs of my main amp.

FWIW, the folding scheme I drew is an expanding pipe (like a BIB or voigt) that is folded one time less than the folding in the Demetri or Mileva. Going vertical makes it tough to get as much length as the Demetri if you shoot for a reasonable driver and overall height. I was actually pondering a BIB folding scheme when it occurred to me, so don't think I was trying to copy Dave's (or Scott's) work. However, their work does lead me to think that the folding scheme would work.

pj

[rjbond3rd]

Originally posted by pjanda1 I'm having a hard time getting an MLTL to sim any different from a vented box with the same Vb and port.

Hi PJ, are you doing it this way (from page 16 of HornResp's Help): "To model a mass-loaded horn specify the mouth cover plate as a conical segment having negative flare (mouth area < throat are) and a length of 0.01 cm, and the mouth mass-loading port tube as a cylindrical exponential segment having zero flare (mouth area = throat area)."

[rjbond3rd]

(Oops, sorry PJ, you posted while I was composing my post, so please disregard my post...)

[planet10]

Originally posted by pjanda1
I drew is an expanding pipe (like a BIB or voigt) that is folded one time less than the folding in the Demetri or Mileva.

Demetri is folded once, so one less fold would be no folds

Your drawing of post 4 differs only in bifurcating the last half of the line instead of the 1st half.

dave

[pjanda1]

Originally posted by rjbond3rd


Hi PJ, are you doing it this way (from page 16 of HornResp's Help): "To model a mass-loaded horn specify the mouth cover plate as a conical segment having negative flare (mouth area < throat are) and a length of 0.01 cm, and the mouth mass-loading port tube as a cylindrical exponential segment having zero flare (mouth area = throat area)."

Yup.

Originally posted by planet10


Demetri is folded once, so one less fold would be no folds

Your drawing of post 4 differs only in bifurcating the last half of the line instead of the 1st half.

dave

I miswrote. Technically, both the first and second half of the line in my drawing is bifurcated as compared to a straight expanding line. And not only are the bifurcated, but separated, whereas the second half of the Demetri is bifurcated but could easily not be with the removal of the divider. But when were semantics important in speaker design?

Right now I'm actually giving more thought to a straight MLTL made of Sonotube. I'll have to see if my new environs harbor decent lengths of big diameter cardboard tubes.

pj

[planet10]

Originally posted by pjanda1
the second half of the Demetri is bifurcated but could easily not be with the removal of the divider.

The brace could be holey, i figured since the line was tapered it really didn't neeed to be.

dave

[GM]

Greets!

FWIW, I did a number of designs awhile back to see what's what and this TQWT with a ~30" wide baffle was my preferred near wall choice, so will theoretically meet your goals also. I prefer higher driver placements, but dropping it down to 36" shouldn't audibly affect performance once stuffed to suit. MathCad sim is 0.25 lbs/ft^3 polyfil evenly distributed along its length to mimic my normal layers of 1" acoustic fiberglass insulation at the top combined with lining one of any other parallel walls.

GM

Edit: Due to the wide baffles, the drivers should be mirror imaged with golden or acoustic ratio offsets.