Friday, November 1, 2013

More on Plywood Horns and Poor Man's Horn Driver

A while back, I posted about the Plywood Horns and Poor Man's Horn Driver.
Since then, I have had the good fortune to discover a couple of  aluminum horn tweeters inside Magnavox 1S8730 speaker cabinets.

Inside The Magnavox 1S8730 Speaker Cabinet
Inside The Magnavox 1S8730 Speaker Cabinet
 I removed both horn tweeters and connected each through a 10 uF capacitor in parallel with a plywood horn driver.


580088-1 Horn Tweeter with Plywood Horn
580088-1 Horn Tweeter with Plywood Horn

The plywood horns are even more efficient since I enclosed the back of the drivers.


580088-1 Horn Tweeter with Plywood Horn and Back Enclosure
580088-1 Horn Tweeter with Plywood Horn and Back Enclosure
When I first tried listening to the midrange plywood horn and the tweeter horn together, the level for the tweeter was higher than the level for the midrange and I had to pad the tweeters with a series 5 Ohm resistor.  After I enclosed the back of the midrange driver, the padding resistor was not necessary.

I have not yet built bass horns to go with this setup.  For the time being, I am using the bass drivers in a pair of KLH acoustic suspension speakers.  I disconnected the midrange and tweeter drivers in the KLHs and the twelve inch woofer and crossover handle the bass quite well.  This setup is "bi-amped" with a Lepai amplifier for the horns and a second Lepai amplifier for the bass.

The volume control for the bass is set quite a bit higher than the volume control for the horns because the horns are more efficient than the KLH bass drivers.

Just today, I listened to the first part of a CD of "Romeo and Juliet" by Berlioz.  This sounds fantastic.