Alcone Loudspeaker Kit: Cauchy

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Alcone Cauchy: Electrical Data/Test Results Description Building Instruction

Cauchy was designed as a classic shelf speaker, that delivers a lot of bass. This type of speaker has become rare since slim floorstanding speakers are on the way up.

Picture left: the
frequency response (red)

response is flat
the speaker goes
down to
29 Hz (DIN,
-10 dB)

In black: the frequency response of the AC 10 HE bass driver. Above 240 Hz the AC6.5 HE midrange driver takes over. It is noticeable that the level at the intersection is 6 dB lower than the total level (red line). This proves that the phase transition is flawless and in phase. At 2200 Hz the tweeter takes over from the midrange driver.

Fluctuation due to the metal diaphragm are well below the critical value (the green line at 6 kHz) and is approx. 20 dB below the speaker level.

Picture left: the
impedance response (red)

green line:
with correction circuit
1.2 mH/15 uF/12 Ohm

The impedance response is quite flat, with the exception of the typical low frequency resonance (one peak each for the bass driver and the bass reflex tube). Those, who want to use a valve amp just need 3 more components to achieve a flat response (green line).

Picture left: the
Decay spectrum

The decay spectrum is well behaved; there is no major resonance. There is just a faint resonance of the AC 6.5 HE at 5 kHz, 2 kHz, 1.2 kHz and below.

Picture left
frequency-
spectrum
under different
angles

It's astonishing that there is hardly any grouping effect. Obviously, under 45 degrees the tweeter doesn't produce higher frequencies anymore; but already under 30 degrees the frequency response is surprisingly flat.

Cauchy Description Lab Results Home