Geddes multiple subwoofer method - 3 subs vice 4


Geddes recommends 3 subs for optimal sound - a different perspective

 

Interesting video depicting Geddes philosophy on using subs. Also, he treats the main speakers as part of the bass solution and does not recommend using high pass filters as this takes away from the total bass capabilities of the entire speaker sub interface system. I am going to experiment this weekend. Also, a higher crossover frequency for the first sub collocated closer to the main speakers is new to me. Recommended above 100 hertz for the first sub and then incrementally lower for the 2nd and 3rd sub in an asymmetric pattern. 
 

I feel like the Geddes approach for sub integration closely resembles what I have been doing for years without even knowing this method. So, my 18” deep bass and 15” mid bass drivers on the field coil speakers become part of the solution instead of being taken out of the equation. That’s what I have been doing and that’s what I thought sounded best to me. Multiple ways to do sub integration but this method is the one that pretty mirrors how I have been doing it for years.

audioquest4life

Showing 3 responses by erik_squires

Well I’m glad to see that several on this thread, including @audiokinesis are taking up the issue of distortion and dynamic range of the mains being something worth considering when adding subs. :)

Too often that behavior gets overlooked for one reason or another.

OP:  Indeed, if you have main speakers which can keep up in terms of dynamic range and distortion in the lowest octaves no reason to high pass them, unless of course you wanted to try listening with low powered amps! :)

 

I will always disagree with using the main subs without a high pass filter as being universally better, especially with smaller mains. The distortion produced by smaller woofers in the lowest octaves is measurable and limits the overall dynamic range of the main speaker, ESPECIALLY with ported speakers.  Plugging speakers used with subs can also further dramatically increase the available dynamic range of the mains.

If you are placing 4x12" or larger subs, then I can’t imagine most main speakers have much to contribute, besides distortion.

If all you care about is maximum bass dynamic range, with no thoughts given to distortion, I guess Geddes is correct. If you care about the entire dynamic range envelope then a high pass on the mains may be just the thing.