Dubravko

So...this is not same thing, bad luck. I will test my speakers to resolve mistery. But, based on pictures, my units are bigger and perhaps lower in frequency response. If they are not suitable for operation I will replace units with some modern before building of plywood horns.

This is one of my mid speakers. I do not have original horns. Any info will be appreciated. Dubravko

Actualy I have problem with mid speakers, last owner told me that this speakers are PD-4 but unfortunately on metal case do not exist any nameplate. I will not be sure until I test speakers with white noise and spectrum analyser.

Plywood is my first choice for material, second one is glass fiber lamination impregnated with polyester resin. My idea is to use two layers of 3mm (~3/32 inch) glued together on mold. I think wood is better material. What will be best way to impregnate horn inside surface, some sort of varnish?

Hi guys... I am new in terms of building horn type of speakers. After some time/money I have in collection Eminence delta 12A, Atlas sound PD-4 and Electrovoice T35 speaker units. PD4 do not have horn. My idea is to make open frame speaker (naked) system with low frequency driver based on Heresy speaker enclosure on the bottom of the mounting frame and PD-4 with Edgar Tractrix plywood horn for mids and on top will be T35 driver. Crossover design will be based on classic E type network. Woofer cabinet design is compresion type. I am not sure what will be better, to build some sort of Heresy speaker with all driver units in one enclosure or to pursuit idea of open frame - modular system. First one is great looking but second one gives flexibility. Dubravko/Croatia EU