Ladies & Gentlemen - The Emken

[GM]

.......i didn't want his old crap *manly tears*

Hopefully, they were grabbed by someone that could appreciate them.

GM

 

[planet10]

like this?

Certainly something to try.

dave

 

[GM]

- for serious music listening, I'd probably want to properly XO them (circa 3500-4k?)

Good guess! In theory, for best overall on/off axis blend = ~3553 Hz using published specs.

GM

 

[planet10]

am i actually doing that whizzer trick properly? any other ideas to try?

The official trick is a slice of low desity foam on edge wedged between the edge of the whizzer & the cone.

Your FR curves are measuring the surface, but any benefit will show up on the bottom (20-50 dB down).

dave

 

[sippy]

Blimey,
Things have really moved on.
Interesting to see the graphs showing where the dips in response lay and the way cone treatment shifts things around.
Is the plugs lack of parallel section below the the cone / voice coil former causing issues?

 

[planet10]

its actually better in most respects than the standard bullet shape was. i got very little improvement from the conventional bullet shape and i had an hunch that the whizzer was just too big for it to work well. so i've flared it out at the end as i've seen in a few other classics of the full range world and the difference was very impressive.

The shape has me thinking of mounting a modified FT17 on the end of the phase plug (bolt thru the pole vent to hold it in place.

dave

 

[JRKO]

Dual Concentric Eminence 12LTA? I know the tweeter is normally mounted on the same baffle as the 12LTA - I wonder if you could get it to fit at the same plane within the whizzer cone. 2 Questions:

1)Would there be time/phase issues with mounting a tweeter there?
2)Would the fact that the tweeter blocks most if not all of the whizzer's direct output be a problem?

I'll hold off letting the the FT17H into the baffle to see what you guys measure on the DC version

Will be playing with 'pluff' around the whizzer and maybe some packing noodles cut into wedges and then some polystyrene as its a bit firmer. I don't think that I'll be painting anything on the cones at the moment. Maybe enABL dots later

 

[planet10]

1)Would there be time/phase issues with mounting a tweeter there?
2)Would the fact that the tweeter blocks most if not all of the whizzer's direct output be a problem?

1/ can't be worsr than fitting it on the baffle.
2/ one should be able to make a tweeter-plug of very similar shape to gaf's. One would start by dremeling off the flat mounting part of the plastic bezel.

For this ap, a very compact horn is required and the FT17 is the most suitable i have.

dave

 

[jimbro]

With a fs of 5k guess you couldn't use the ft17 for the 3553hz GM suggested. What would the xover point be? Would the rule of twice fs apply? If so 10k?

 

[tuxedocivic]

I'm not familiar with that tweeter, but what is the driver type? Compression or direct radiator? I looked up quickly and Fs is 2600hz. Probably can go close to it depending on filter and the tweeter.

 

[jimbro]

I'm not familiar with that tweeter, but what is the driver type? Compression or direct radiator? I looked up quickly and Fs is 2600hz. Probably can go close to it depending on filter and the tweeter.

Madisound Speaker Store
Where did you see 2600?

 

[jimbro]

O.K. I googled it and found 2600hz cut-off freq. Could they be talking about the physical cut-off of the horn but not fs?

 

[planet10]

Given the mouth size, 5k seems about right.

dave

 

[tuxedocivic]

See the spec sheet: http://solen.ca/pdf/fostex/ft17h.pdf

Madisound made a mistake.

5khz is probably a good place to cross, but 10khz is higher than needed probably. Sure could if wanted though.

 

[JRKO]

I'm using a single 1uF cap - cant remember for the life of me where that crosses over now and cant find it in my notes either.

any reading on single cap crossovers?

 

[tuxedocivic]

That'll be way up there. Around 10khz.

Don't forget though there will still be output below the -6db or -3db point contributing to the output.

Have you tried others sizes?

 

[planet10]

I'm using a single 1uF cap - cant remember for the life of me where that crosses over now

1uF into 8 ohms is 20k.

dave

 

[jimbro]

Formulas as I understand them - to find cap value - C = 1/(2pi)FR. R being imp. of driver. To find freq - F = (1/(2pi)R)/C
So for ft17h and 1uf cap - F = (1/(2pi)8)/1uf = 20k
Glory be it's rainin down in Texas. Not floodin but I'll take it.

 

[tuxedocivic]

Wow, you might wanna try a bigger cap JRKO. Maybe 2uF. Maybe even bigger than that.

 

[sippy]

Any one got a response chart for the 12lta? - I'm struggling to find one