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.


Dear @deep_333 : I really appreciated your post and you can be sure that I will do all those.

Tou touched a critical issue in the subs correct integration to the room/speakers: PHASE that almost no one really speaks about when are talking of subs and " playing "/changing with comes with very high rewards that for me were unexpected to say the least.


By coincidence and before read your post last nigth I was " playing " with subs Phase making some changes ( btw, we modified the phase control in the HGS to go from only two phase positions to almost continuous changes. My HGS have several modifications made it by a friend and me: I changed the stock internal wiring from the drivers to the amp for pure silver KK cable, I by-passed all the internal fuses and changes passive and active parts in the input board and internal crossover circuit board. Even I change the damping foam by long hair virgen wool. The subs are at around 20 cm. from the floor and have a dead weigth of 30kg at the top plate. ) and I did it using CD MUSIC source as " Day after Tomorrow " that at its very first track comes with deep bass made/using synthesisers and I use other film soundtracks as Gladiator and the like and late in the nigth I gone to sleep but not totally satisfied.

So, I wake up early today and followed playing with phase changes this time doing with LPs mainly using the Telarc 1812 that has a wide kind of different bass frequency ranges and recorded with acoustic instruments and not synthesiser that’s different and after the changes with the phase finally I was truly satisfied with and learned the critical importance of PHASE about.

Thank’s for your knowledge advise. I’m just learning what it’s exiciting to me in that critical sub/speaker subject. Thank’s again.



Another advantage in my sub/speaker is that the sub driver is of pulp/paper cone as are the ADS speaker woofers drivers, so exist synergy in the sound reproduction.



@rauliruegas  If you should happen on a used Plus in any size I think you might be amazed. All the best.

Dear @phusis  : " I don't buy into the music vs. HT subs distinction. "

Agree, my mistake.


" while I myself opt for horn-based subs.... "


In general I like the immediacy of the MUSIC reproduced sound that's a main live MUSIC characteristic. One " but " on horns ( at least to me ) is that I don't like its reproduced sound seated at near field position ( say 2m. ) I think we need at least no less than 3m. and obviously that depends of the room too. At near field position my ADS are way better than horns or electrostatics.

Unfortunatelly  I never had the opportunity to listen a true horn subwoofer ( at least that goes to 16hz. ) but I tend to beleive you.



Dear @deep_333 : My room geometry is not easy to use the Harman calculator, these are more or less the dimensions/shapes:

as I posted my apartment has 2 parlors from the entrance door. First parlor where is not seated the system its wall distance to the other extreme, where is the second parlor/listening area/system, are 9.70m to the window that’s behind the speakers.

Now the speakers are at 95cm. in front of the windows and the left speaker is at 30cm. from the side wall, the rigth wall is at 8.5m from the left one.

The center of the speaker tweeters in between are at 2.60m and the speaker woofers at 3.05m.

Listening area length is 4.70m and the wide is around 4.5m. Exist a passageway of 1m. wide by 14+m. in length. This apartment has 3 bedrooms and two complete bathrooms. All in one floor, so is a little big.

Dining room is big and the dining room central/rectangular table is for 10 seated people.

Both parlors are full of ( mainly ) wood furniture as the dining room and all around exist wood display cabinet ( like seven of them ). The parlor furniture are made from natural absorbtion materials and due to the shape of the wood furniture it works as difussors.

Rigth now the system is working truly fine and till today I think that I can’t do ( ? ) anything to improve its very high quality MUSIC reproduction and very high resolution.

It does not matters the SPLs the room/system just refuse to distort: MUSIC stage always is there/nothing change but SPL. Yes, its noise floor and distortions levels are so low that can be dangerous to the ears with out taking in count due that we can’t be aware of those distortion levels. No, I normally listen at around 82 or even a little lower db SPL and only during some kind of system audio items tests I listen at 95db with peacks at 105+db for only a few minutes.