Hi, my name is Jeff Markwart, and I’ve used numerous Altec Lansing Professional speaker products since the late 1980s in home stereo settings. I’m referring to the Altec Lansing Professional Products that were produced from the 1940s through the late 1990s, and are best known as “Voice of The Theatre” components. Like many Altec users, I’ve been able to achieve improved sonic performance from these amazing inventions by making small changes to drivers, enclosures and crossovers.
My “Corner” of the GPA website is intended to provide useful information to audio amateurs and others who are seeking improvements in the sound of their Altec speaker products. I do not manufacture nor sell any of the crossover solutions I have listed here for the Altec 604 and 605 series, but rather encourage the Audio Do-It-Yourself community to further experiment with my ideas on their own. My crossover designs are free for non-commercial use.
Although my original idea was to publish my Altec Duplex phase corrected crossover designs, it continues to grow and now includes a number of related vintage Altec Lansing items of interest.
Altec Lansing 604 & 605 Crossover Options
The following posts and referenced pages contain some ideas I’ve had about improving Altec 604 & 605 Duplex crossovers.
If you would like to discuss my Phase Corrected Altec 604 crossovers, head on over to the Great Plains Audio Altec Lansing Community.
Follow the links below to download and print sections of the Vintage Altec Lansing Model 19 Cabinet Plans for use in your wood shop. Refer to the Model 19 Cabinet Plans page for NOTES that accompany the plans. Altec Lansing Model 19 Front View Altec Lansing Model 19 … Continue reading →
Here are two articles I contributed to from Sound Practices magazine. They are reprinted here with permission from Sound Practices. Sound Practices, Vol. 1, #4, Altec “Voice of the Theatre” Speakers for Hi-Fi Sound Practices, Vol. 1, #9, Horns Revisited … Continue reading →
In the spring of 2008 I was loaned a pair of Altec Lansing Super Duplex 604E for testing and research about possible crossover improvements. Unfortunately, one of the drivers had sustained damage to a compression driver binding post during shipment, … Continue reading →
I received an unexpected opportunity to perform electro-acoustic measurements on a pair of 604E Super Duplex speakers in early 2008 thanks to a long-time owner seeking improvement in their sound. He had been using the original Altec Lansing N-1500A series … Continue reading →
The Great Plains Audio 604-8H-III is a much improved version of the vintage ferrite magnet Altec 604 family, and is currently in production. Compared to the early production ferrite Altec 604-16X discussed elsewhere in these pages, the GPA 604 exhibits … Continue reading →