Which Qts to look for, for a Ripole?

[KSTR]

As for suitable Qts of the raw drivers, don't be afraid of 'too low' values. EQ them to desired target and/or use an amplifier with high ouput impedance. The latter will also change the large signal distortion, sometimes for better (depends on the nonlinearity of the motor vs. the nonlinearity of the suspension). In general, T/S parameters tend to get overrated.

 

[sreten]

Oskar Heil and his then apprentice, Nelson Pass, would surely disagree.

Hi,

Don't no about O.H. but N.P. totally lost the argument
we had regarding this issue, so I simply don't care.

rgds, sreten.

 

[KSTR]

Then any AMT would not be an AMT as well.
A pleat depth of 5mm with 1.5mm spacing putting out 3kHz with 0.1mm pleat excursion is exactly the same thing as a pleat depth of 500mm with 150mm spacing putting out 30Hz with 10mm pleat excursion, isn't it?

OK, total radiation surface and footprint area in proportion to wavelength is different, hence air load (radiaton resistance). But nothing is stopping us to stack up a bunch of W-frame Dipoles directly at two boundary surfaces (floor and wall) so air load will get comparable again. Also, a tweeter AMT is working in to free air space while a woofer AMT isn't unless the room is extremely large.
But those two points have nothing to do with the principle.

 

[sreten]

Then any AMT would not be an AMT as well.

Hi,

Totally irrelevant. of course an AMT is a AMT. It works by increasing
total diaphragm excursion. It too is not an air motion transformer.

rgds, sreten.

 

[KSTR]

An 'air motion transformer' is by definition the name for a transducer where the air particle velocity at the "output" of the driver is significantly (like 4x) higher than the diaphragm velocity, according to wikipedia. Why do you say this isn't true, both for HF and LF AMT's?
I do agree 'air motion transfomer' might not be the best nomenclature.

 

[sreten]

An 'air motion transformer' is by definition the name for a transducer where the
air particle velocity at the "output" of the driver is significantly (like 4x) higher
than the diaphragm velocity, according to wikipedia. Why do you say this isn't
true, both for HF and LF AMT's?
I do agree 'air motion transfomer' might not be the best nomenclature.

Hi,

By that definition putting a slot in front of anything is an AMT.

My definition of an AMT is anything that outputs more air displacement
than that occurring at the cone, that an impedance transformation occurs.

The AMT tweeter is just cleverly folded, but output is still directly related
to the total diaphragm displacement, there is no transformer effect.

rgds, sreten.

 

[welborne]

sorry to revive this old thread

Dear all,

I have 4 vintage Teala 15" with huge alnico magnets. They are 30ohm versions. I am using them on a big open baffle but thinking about putting them into a cone-cone Ripole. It's really hard to find their t/s and these are what I found from one of the posts on diyaudio:

Diameter [mm]: 390
Depth [mm]: 231
Impedance [ohm]: 30
Power [W]: 15
Peak power [W]: 30
Fs [Hz]: 24
Frequency range [Hz]: 24- 4000
Efficiency [dB]: 100
Weighy[kg]: 10.50
[Qts]: 0.4
[Vas]: 226
[Xmax +/-]: 4.50 mm

Can anyone shed some light as to their suitability for Ripole bin?

Advice appreciated.

 

[GM]

As noted/implied in post #5, except for the low power/Xmax, the specs are quite good, just won't have much bass except near a corner, though with [4] closely coupled will in theory peak out at a little over 100 dB/m/24 Hz further out in the room. With such old drivers though, best to measure all yours, then average the specs to see what's what.

GM