A-290 Wood Horn

Jungfrau, Swiss (Photo by Yuichi)
A-800 Coaxial Wood Horn Specifications
= Horn Contour : Hyperbolic curve
= Cut-off frequency : 800Hz
= Frequency range : 800Hz or Higher
= This horn was designed for Altec-604-8G and Gauss 3588 coaxial 2
way horn system. This horn can be used as a replacement of
original horn.
: The A-800 wood horn may improve mechanical resonance caused
by the horn mouth. The wood material has higher mechanical loss
than original plastic made horn.
: The Horn itself is the same for both Altec and Gauss.
Only deference is the adapter portion to conform with each bodies.
A-800 Horn may be applicable to other 38cm coaxial type drivers.
However, mechanical tolerance between the horn and the
diaphragm have to be carefully considered.
Caution: Modification of the speaker driver is on your own risk !!

Feb. 1991issue of MJ for ALTEC and
Dec. 1991 issue of MJ for GAUSS (Photo)

Building and assembly process

Gauss 3588 38cm coaxial
horn system
Original horn construction Coarse cutting of A-800
horn mouth pieces
Formation of the mouth
by the table sander
Side formation by the belt
Horn and adapter pieces Generation of mouth
contour by the belt sander
Bonding of four pieces by
epoxy glue
Surface finishing of the
horn body
The adapter-2 formation
Surface coating process Completed pedestal piece

The pedestal is mounted
to the center magnet of
the driver first by two
screws, then the horn
with two adapters is
screwed on this pedestal.
Assembled horn with
adapters and the pedestal
Side view of the horn Final assembly on GAUSS
Returning of the dust
The A-800 horn body is
the same as for Gauss horn.

Only deference is the
adapter portion. Please
refer to the drawings
which are in the
Download section.
ALTEC 604-8G
Removal of original horn Original horn structure A-800 Horn and adapters
Forming of the adapter
by the hole saw
Rear view of the horn Front view of the horn Mounted horn on ALTEC
604-8G driver

Physical Properties

Gauss Original Horn System

Frequency response curve of original
GAUSS 3588 coaxial horn system is
shown. Measurement point is on the
center axis.

Cut off frequency is observed as 2KHz
from this curve.
Sound pressure level higher than 10KHz
is maximum 5dB less than the flat level.
Some acoustic impedance miss-match
can be seen in higher than 10KHz
domain on this driver.

A-800 Horn on GAUSS-3588
Frequency response curve of A-800
horn on GAUSS 3588 driver is shown.
Cut off frequency looks about 1.3KHz.
Sound Pressure Level is much smoother
than the original horn. This means that
acoustic impedance matching to the air
is better.

: Flat frequency response
: Lower cut off frequency
: Less horn resonance (not measurable)
Service area property of Front

: Left = Original horn
: Right = A-800 horn
: Upper = Horizontal service area
: Lower = Vertical service area
: Frequency = 5KHz and 10KHz

: A-800 horn shows better
directivity distribution property
for horizontal space for both
5K and 10KHz.
: In vertical space, original horn
has better directivity distribution
in 5KHz case.

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Jungfrau, Swiss (Photo by Yuichi)