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-   -   Hemp FR8 MLTL (http://www.diyaudio.com/forums/full-range/73469-hemp-fr8-mltl.html)

jimmyd53 6th February 2006 05:13 PM

Hemp FR8 MLTL
 
Has anyone used the Hemp FR8 driver in Martin King's MLTL?
Hemp FR8 vs Fostex FE207E in this application?

papparazzi 6th February 2006 08:47 PM

Hi

You thinking same as me ? This looks also good

http://www.boxen-baustelle.de/

And kits

Papparazzi

VadimB 6th February 2006 09:50 PM

How does it sound?
 
Looks like you've actually built this system with Hemp 8FR. How does it sound? Did you have to use any correction elements to fix the rising response?
I am planning to build a back-loaded horn for this driver. Already ordered both the drivers and the cabinets, but have not got any yet. In case this approach does not work right, I am very interested in alternative solutions.
Any info would be greatly appreciated.

Vadim

Dumbass 6th February 2006 09:57 PM

With its higher Qts and higher Vas, I don't think the Hemp driver would work optimally as a drop-in replacement for the FE207E in Martin's design. I think you'd get a significant hump around the 100-200Hz region.

AFAIK you would have to increase the cross-sectional area. I don't think you'd have to change the length or port dims.

If you have the ability to run his worksheets (Windows machine), you could start with the FE207E worksheet (make sure it matches what he has on his web site), then substitute in the Hemp params, then work with them until you like what you see.

Dumbass 6th February 2006 10:01 PM

Quote:

Originally posted by VadimB
I am planning to build a back-loaded horn for this driver. Already ordered both the drivers and the cabinets, but have not got any yet. In case this approach does not work right, I am very interested in alternative solutions.
Any info would be greatly appreciated.

Hm, which horn design? I'm not sure the FR8 would be terribly well-suited for rear horn-loading, but am prepared to be shown wrong.

See my post above for how I would approach the driver. I would make the cabinet cross-section relatively wide-and-shallow because I am of the "large baffle" school.

dmason 8th February 2006 12:46 AM

I have the drivers with about 30 hours on them. They are becoming extremely impressive. I can understand why so many electric guitarists are swearing by them; the critical midrange is a high calorie treat, let there be no doubt. Abit hot on top, but this is evening out fairly quickly now. More than alittle alike the B200, which is The Best thing I could say about it.

With a Qts=.42 I would not recommend backhorns.

Scottmoose: you reading this? Here is the ideal 8" BIB driver.

Highly Impressed thus far. A+

jimmyd53 8th February 2006 06:58 AM

Dmason,
What kind of enclosure are you going to build for your FR8's?

VadimB 8th February 2006 12:42 PM

Dmason wrote:
Quote:

With a Qts=.42 I would not recommend backhorns.
I've seen this argument many times, but without any reason. Can you, please, give an explanation what exactly is wrong with using a driver with Qt>.25 in a BLH? I still have time to back off from this approach.

Also, what cabinet are you using with Hemp 8?

Thanks, Vadim

dmason 8th February 2006 01:14 PM

Jimmy

The Hemps are in a cab of about 40L, I would say. They are the latest Omega SuperHemp, the pair sent by Louis for me to audition and show.

In the larger cabinet, they dig very deep into some real bass, using a Pass F2, and the 41Hz test is easily passed, with some fundamentals exhibited due to room gain, etc. They are pushed very nicely by 2 watts parafeed as well, to mention.

Vadim

I stuck a pair of Fostex FE167E into the Fostex Rx horn load while I waited for the FE166esr to arrive last year from Madisound. With a lower Q than the Hemp, by quite abit as I recall, the balance was still waaaaay off in a horn load. ,but I personally would NOT build a pair of horns specifically for a driver sporting a Qts=.42. Thorsten Weber has built a MLTL which looks like a great idea. (see above link) Also, I should mention that a rear loaded tractrix horn, or The BIB, idea of Terry Cain, calls for a mid Q driver exactly like the Hemp. In fact, I intend to build a pair soon, these are perfect, and the BIBs are as easy as pie to build. So there is your better alternative. Scottmoose is the resident Jedi Master of running the BIB numbers thru Martin King's spreadsheets. In BIB load, the hemps will certainly deliver. We would be talking about stunning full range sound.

These have a crisp, warm, organic sound not unlike the Altec coaxials as I recall. Again, very early days with these drivers, I would not say they are near loosened up, and yet already starting to really sound sweet.

I knew all the guitarists addicted to using Tone Tubby hemp cone drivers could not be wrong. Have a look.. www.tonetubby.com

VadimB 8th February 2006 01:23 PM

Quote:

With a lower Q than the Hemp, by quite abit as I recall, the balance was waaaaay off in a horn load. ,but I personally would NOT build a pair of horns specifically for a driver sporting a Qts=.42.
Dmason,

Can you, please, give a little more details: which way the balance was off? Was there too much of midbass, or mids, or heights?

Why do you think higher Q is not good for the horn? What goes wrong?

Thanks, Vadim


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