Arai 480


  • Horn Type : Hyperbolic (T=0.7) Constant Directivity (CD) horn
  • Coverage : H 95°, V 40°
  • Cut off frequency (Fc) : 480Hz
  • Frequency range : 900/1000Hz to 20KHz
  • Driver : 1" throat like 18Sound 1095N or TAD 2001/2002 or equivalent
  • Size : W 433mm, H 145.4mm, D 276mm (inclu. 20mm adapter plate)
  • Material : Chinese quince laminated lumber (3.0cm thick)
  • Finish : Two coats of oil based clear polyurethane varnish
  • Four fins (separators) inside the horn


Note that the 18Sound 1095N have almost the same THD/CSD performances of a TAD 2002 and can be cut (strongly) at 900hz for 10% of the price so...

Same for TAD 11", the 18Sound 12LW1400 is the best combo with Arai 480 + 18Sound 1095N.

Drawing files: 


Yuichi recommend to use drawing file for  re-draw your own at 1:1 scale on a hard paper as a construction template.
These templates are very important to make accurate horn curves or contours.

For now it's the original PDF, as see in Horn Design section some information is not strictly exact :
A480 PDF

Building :


A more modern way to do it is visible here (in french but there is a lot of pictures) :
http://www.cinetips.com/viewtopic.php?f=40&t=698

Yuichi Arai original content:

Forming side curves
A belt sander can be used
for fine adjustment.
Two 30mm thick lumbers
are bonded by epoxy.
12Hours for curing.
Making contour in upper
and bottom horn pieces
A plane is used for
coarse adjustment.
A belt sander and a
orbital sander can be used
for surface finishing.
Forming of fins
A belt sander can be used
Forming of side walls
A electric hand plane
can be used.
Verification of joints
among horn pieces prior
to apply Epoxy
Assembly of side wall
Epoxy glue and screws
are applied.
Mixture of epoxy and a
Chinese quince wood
powder is used as filler
Application of plugs and
filler after final assembly
process
Finishing process by a
rotary sander and
sandpaper
Rear view from the horn
throat (1 in x 1 in)
Edge of fins can be seen.
Driver adapter craft
1 in or 25mm hole saw can be used.
Left side is horn side and
right is driver side.
Inside is epoxy coated.
Positioning of adapter on
the horn throat
Rear view of the horn
Bolt holes can be seen

Making of mortises for
nuts by drill hole saw
Application of two coats
of clear polyurethane
vanish
Competed horn assembly
and driver adapter
Pioneer TAD TD-2001 is
mounted on the horn.

Measurement:


Frequency response data is shown in the left hand side.
Pioneer TAD 2001, 1 in or 25mm throat, driver is mounted. The response curve maintains very flat sound pressure level from 700Hz to 20KHz.

This horn with TAD 2001 or equivalent driver covers high frequency range in two way system. However, high frequency response depends upon the driver capability though TAD 2001 shows good response.

Recommended crossover frequency is 900/1000Hz depending to you driver when harmonic distortion order 2 or 3 rise too much.

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