Do you think you need a subwoofer?

@rauliruegas It is phase and time. The Australians call it " launch time"  The sub has to be in phase with the main speakers and the signal from the main speakers and subwoofer have to reach your ears at exactly the same time. Changing only the phase angle of the subwoofer is going to change the amplitude response of the system is unpredictable ways. The system may sound better or worse depending on taste and even the music you are playing. It can drive you crazy. One minute you think you have it sounding great, the next minute not so much.

@lewm  Many subs have continuously variable phase angle over 180 degrees, but without the ability to match arrival times the phase angle control is a real double edged sword. Once matched in time and phase everything sounds great. You REALLY need to try subwoofers with your SLs. Get an inexpensive MiniDSP  crossover to start. This will give you a good idea what the advantages are, then you can get a more elaborate unit down the road. Benchmark Media Systems uses a MiniDSP SHD studio and two of their own DACs.

I just finished the first pair of model 4 subwoofer. I'll be putting a picture on my system page. 

Dear @mijostyn  : " One minute you think you have it sounding great, the next minute not so much. "

More or less is what happened when started to test it that nigth but from yesterday till today the romm/system reproduced sound is just nothing less than sublime.

Last time I seen your virtual systwem the subs were directly seated in the floor, for me not the best any sub position. The new cilindrical boxes looks fine and similar to a transmision line subs that I listened several years ago. Have good luck with.

R.

Dear @secretguy  : " And in the wrong category. "

Could be but when started this thread I decided in that way. Not many analog lovers were using subs in their systems like today times. In those old times and through this thread several gentlemans ( including me ) learned a lot about this subs crucial/vital audio subject.

R.

@rauliruegas I never said that! From the second I first fired them up I knew Sub model 3 was deficient, but I did learn a lot from building them. Sometimes you have to know what does not work to know what might work. Sub model 4 was inspired by Magico's Q subs, except I took it several steps further. 

The most efficient location for subwoofers is in a corner followed by up against a wall, 6 to 9 dB more efficient. The problem with these locations is you can not integrate the subs properly with strictly analog equipment. It requires digital bass management.  You are putting the subs where they sound best. I am putting the subs where they work best then making them sound even better.

My subs are not transmission lines. They are a balanced force, acoustic suspension (sealed) design with resonance free (and I mean totally resonance free) enclosures. The walls are 1 7/16" thick. The 10 sides are only 4" wide and they are arranged in a cylinder, an inherently very stiff structure. They are much smaller and lighter than the Magicos making them more practical in all situations. They weigh just over 100 LB each. There will be four of them eventually forming an 8 driver linear array. They are 2 dB down at 20 Hz without any processing. @skoss heard them yesterday. You might ask what he experienced. The picture is up on my system page. 

The sound is not where I want it yet. The system is now dead flat from 20 Hz to 12 kHz. I can boost the subs by adjusting their volume relative to the stats, but this makes the bass too warm. The sound is also on the bright side, again because to is corrected to flat. There will be a EQ program in the DEQX and it is supposed to be in the next upgrade. That will allow me to program the amplitude curve to my taste, bass increasing 3 dB/oct below 100 Hz and a shallow drop from 1000 Hz so that 20 kHz is down 6 -12 dB. 

@rauliruegas I think I had the wrong member. It is @sksos ​​​or @sksos1 who heard them yesterday.