Midrange K-tube ?

[freddi]

for testing, just tape the tube to the CD

 

[zobsky]

I tried some 3/4 " PVC pipe mates to my compression drivers via a reducer .

Sounded somewhat better than the larger 1 1/4 " pipe even through the graphs don't show it. This is workable as a tweeter, though probably not as a midrange as originally intended . As in the previous experiment, the eminence sounded better than my mcm paging driver.

 

[zobsky]

Response

 

[freddi]

that's a cool looking tube - maybe for helper tweeter use try ~3.5 " long (?)

a 1" pipe ~5.3" long should sound pretty good and better than some CD waveguide provided a high enough xover.

An externally hosted image should be here but it was not working when we last tested it.

 

[zobsky]

that's a cool looking tube - maybe for helper tweeter use try ~3.5 " long (?)

a 1" pipe ~5.3" long should sound pretty good and better than some CD waveguide provided a high enough xover.

An externally hosted image should be here but it was not working when we last tested it.

I agree, dispersion is good and doesn't seem to have too much drop off with increasing frequency .

 

[IG81]

I missed it if it has been mentioned, but was there any Xover on either set of measurements? I see no other reason for either the paging CD or PSD2002 not to have solid output down to at least ~900Hz.

 

[zobsky]

I missed it if it has been mentioned, but was there any Xover on either set of measurements? I see no other reason for either the paging CD or PSD2002 not to have solid output down to at least ~900Hz.

No crossover, though the measurements were farfield in-room . Over the weekend, I might re-measure with the tube axis pointing straight at the mic and the slot facing upwards. Wondering if angling the tube or pointing it at the ceiling would be better since the slot arguably diffracts the sound away from the axis.

I can try and take some more SPL measurements outdoors (as well as impedance measurements).

 

[IG81]

Yeah, I suppose you'll measure less output around 1kHz when far enough.

 

[zobsky]

Not a lot of difference in the measurements with different tube orientations . Might just be the room. I might have to listen to them playing actual music to discern the differences

 

[freddi]

the output of a tube perpendicular to the long axis seems to compliment the other perspective
the other device on this graph is Speakerlab's "wide angle" version of EV's T35 - its not attenuated
so the tube is ~10dB hotter. my 3.3uF/0.55mH highpass was not optimal for the DE25/K-tube combo.

the little Speakerlab horn was an early constant directivity tweeter

An externally hosted image should be here but it was not working when we last tested it.

 

[zobsky]

And some poorly recorded video of a contraption I lashed together with bass from the bottom half of a econowave with a Dayton dc300 12" driver. The k tube is running full range . Padding is via the balance control on my receiver Comapred to the recording , it does sound better in real life. The hollow reverb in the recording is an artifact.

I think I will experiment with an 18" k tube. The smaller diameters do sound somewhat better .

Karlson k tube on eminence psd 2002 compression driver - YouTube

 

[kenpeter]

Wow, impale your head on the point we can almost hear treble.
Amazing what bone conduction does for a KTube. Who knew???

Bust out my old Klothespin if you can find it. Constant sucktivity.
After you've re-heard that fail, yours will sound much improved.

It did brighten a DeltaPro12 when held about 1/4inch gap above
the dustcap. The gap was important to the sound more than just
not hitting the moving cap, I don't know why. It still wasn't good
by comparison to the whizzer on an LTA.

A long thin one might work if bent into a log spiral section?
I don't believe any off-axis hope exists for the straight version.
To get any treble off the side, a straight tube has to be cut so
much it ceases to boost mids, rather pointless. Maybe needs
some curve to encourage the wave to exit a usefully thin slot.