Hasling Audio Systems 2007.
October 10, 2011. ©
1: Beach sand.
4: Electronic kitchen scale.
|7: Wooden stir stick.
8: Measuring glass (ccm).
Start with measuring the front bow volume, to find out how large a portion you must blend in the disposable plastic cup to fill up the bow minus 2-3 mm from the top. When you pour the resin blend in the bow, remember that the horn must be adjusted horizontal in both horizontal directions, by adding to the hight at the back of the horn with pieces of wood and cardboard, to get the frontbows horizontal.
It is prudent to place a big piece of cardboard under the horn to catch any dripping during the process.
The mixing ratio between the amount of resin and hardener is weight, e.g. 100g resin/22g hardener, see the manufacturers specifications. The volume of this is typical approx. 122 ccm for 122 grams of blend.
Relationship between amount of resin and hardener is weight, f.eks. 100 resin/22 hardener, see the manufacturers specifications. The volume of this is typical around 122 ccm for 122 grams of the blend.
Altec 811B horn: 450 ccm/bow, totally 900 ccm for both bows.
Altec 511B horn: 1250 ccm/bow, totally 2500 ccm.
Resin/hardener: E.g. D-Araldite and hardener, 1 kg can + hardener. Ciba Araldite D AY 103 + hardener HY 956 or equivalent product. Pot life 1 hour.
Blend 460 ccm mass in this way. The volume of the plastic cup is the following: mark at 450 ccm, but can hold 500 ccm.
Part 2, will deal with the damping of the top and bottom bows behind, which I strongly recommend also to carried out. The horns will sound beautiful when finished, very neutral. Any ringing is completely gone. When standing just in front of and close to one of my 511B horns, there are no bad sounds in my usual working range (500 to 6000 Hz), but clean, clear, well defined sound, and fine horizontal spreading.
Hasling Audio Systems, Denmark.