The different projects


Klinger Horn part 3.

 The Eminence driver ME150-08 Thiele Small parameters

In red the Eminence driver and the Philpips in brown and Gamma in black.
I have changed the curve layout and added will use the Eminence as a reference as it very close to the current Gamma 12A Surprisingly the Philips and the Eminence is close to identical, with the Gamma weaker in the bass.

 Then it was time for the Fane Cresendo 80W

Very similar Fane Cresendo 80W and the Eminence in the klinger horn

Then it was the classic vintage horn driver Isophon 30/37A
The driver has a large plastic cup covering the magnet, the purpose of this I do not know.
Also in this case very similar to the Eminence.

The finaly the Beyma G320, For some reason way out of spec with Fr in the 70-80 Hz  range. With twise the weight of any of the other drivers they are monsters.
Here the 60 Hz peak is reduced  4dB, the 70 Hz peak by 2 dB the 95 Hz peak has shifted down to 85 Hz. If one could cut 3 dB or so of the 85 Hz peak the horn would be 35-130 Hz +/- 3dB. If damping material, corner reflectors or internal Helmholz resonator would do the trick is a matter of some experimental work to find out.

Next up is vintage  Philips bass driver

If I measure the drivers myself using Woofer Tester 3 I get very similar (and good) results.
When measured mounted in the horn:
Omnimic Near field and in horn mouth

Quite similar result to the other closed box driver the Gamma LA1231, In the Philips data sheet there is peak at 1.5 kHz and then a rollof above 2 kHz, in my nearfield measurement I do not pick up that peak but the roll off is more or less as specified..

The horn output in the 35-45 Hz range is 5 dB down compared to the two peaks at 60 and 90 Hz. That is a 5 dB improvement as compared to the Gamma driver, not bad.

Now I am out of closed box drivers and I will try out some PA drivers. First out will be an Eminence ME12-1508 driver, according to Eminence the driver is a version ordered by their european distributor and it is the same as the  Delta 12A of their standard set of drivers. Thiel Small paramterers are the same except for inductance that is higher but that is a tricky parameter to define as voice coils do not behave as text book coils.


New horn project. A classic about 50 years old. A backloaded horn for 12" drivers. It is acually built in soft board and then has a shell of chipboad around it.

 I had some initial trouble as the horn is made for rearmounting the drivers and the lid is to small to fit many of my drivers. So I made a external baffle that could take drivers either way. The baffle was screwed and sealed to the front.

The first driver that I tested in this horn using Omnimic and Woofer Tester 3 was the Bulgarian Gamma LA1232, that worked surprisingly well in the Kuben horn. Low Fr of about 30 Hz huge Vas of 300 liter and moderate Q of 0.4 hardly a classical horn driver

This is how the near field response is mid center about 5 cm in front of the dust cap

Mouth opening in the middle (all measurements on the same spot.

Falls  rapidly below 50 Hz and has some  4 dB peaks at 55 and 90 Hz. The sound is surprisingly good with those soft board panels I expeced no bass and all buzzing vibrations but it does not sound that way. The Klinger is about 300 l and the Kuben about 200 l so I had higher expectations than that on the Klinger, perhaps an other driver...