half chang with lowther and BSC ?

[hornophile]

Hello,

I was wondering if it would make sense to use a lowther pm2a driver in an half chang enclosure with bsc as designed by Martin King for his lowther MLTL.

I had this idea when reading a thread concerning half chang where it's stated that the half chang with Martin's bsc sounds quite good.


Thanks for your opinion !

Guillaume

[Scottmoose]

You might get away with it, but it's a case of trying to stuff a driver into a cabinet that isn't actually designed for it.

The variable BSC circuit in the case you are thinking of, I suspect, isn't actually correcting for step-loss so much as the rising response of the FE206E which happen to be in that particular pair (they weren't designed for that driver either; they were designed for the FE207E). Fortunately, they're the same width, so the variable circuit at least doesn't require any changes.

[hornophile]

ok thanks for the answer !

Nevertheless, hereafter is the post of Martin King I was refering who lead me to think that the half-chang would be a better enclosure for a lowther with bsc than the more "simple" MLTL enclosure described in MJK website :



"Bob and Jim,

Definitely a great afternoon, thanks for having us Bob.

The Half Changs are a definite winner. I think that the bigger mouth, compared to a ported ML TL, helps the bass cover a wider low frequency range then is typically covered by a simple port. These speakers are about the same size as my Lowther ML TL but I think that the bass output was definitely stronger. The Fostex FE-206E has similar properties to the Lowthers and we used a lot less resistance in the BSC circuit to balance out the upward tilted SPL response that is typical of this type of driver. As Bob said, the impact on efficiency was minimal. I have to look harder at this enclosure concept.

I also really liked the way Bob finished his two sets of speakers. The black painted baffle and top made a nice contrast with the light wood stained sides. They looked good in the pictures and better in person.

Scott did a terrific job on this design, I cannot even begin to imagine what it would sound like as a double horn.

__________________
Martin

Quarter Wavelength Loudspeaker Design
www.quarter-wave.com

[Scottmoose]

Yes, I remember that one. My ears were burning a bit because I'm the Scott who designed it. The cautionary point I was raising is simply that a cabinet is designed for a particular driver, so you can't automatically drop something else into it & get good results. A lot of people try that sort of thing, and run into trouble, which can put them off. Lowthers for example, are often dropped into boxes which are simply not optimised for them, and get a dodgy reputation in some circles because of this.

In this case however, you're in luck: going by the parameters for the PM2a that I have, it should go straight into that cabinet, no mods needed. The alignment changes to an EBS, but that should blend into room-gain quite nicely, so no bad thing. Excursion isn't half bad either. I'd take it over a regular MLTL, that's for sure. Everything's a compromise of course, but coupling to more air has it's advantages in scale, which is something FR drivers can tend to struggle with.

[hornophile]

ok thanks for the answer !

It's very nice that you take your time to answer to the various persons in this forum, even the ones with silly questions :-)

Btw, I'm a regular reader of this forum and the reason I wanted to try this half-chang over a regular mltl was that I 'm a great admirer of your work as a designer and I wanted to try one of your design.

In the futur, I'm also interested to build the sachiko (although I know too that's not optimised for lowther) or maybe if you draw one in the future, a specific lowther design !

Meanwhile, for a first time build I want to try something simpler and easier but still good sounding;