Do you think you need a subwoofer?

@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. 

@mijostyn  : Sorry but your post has no meaning for me or I made a poor explanation in my other post.

R.

Dear friends : In this subs issues we have to follow the Physics rules. Here a room mode calculator:

Room Mode Calculator_0.xls (live.com)

and here why at one seat position 2 subwoofers are good enough to listen MUSIC, we don't need 4 but we can use those 3-4 additional in HT but not need it for MUSIC only:

Microsoft Word - whitepaper10.doc (harman.com)

R.

" Two subwoofers, at opposing wall midpoints, performs very nearly as well as four at the midpoints and gives a much better LF factor. "

That’s the Harman conclusion. Now, if we are using our room/system mainly to listen MUSIC where is the bass range we need be reproduced by subwoofers?

Mainly from around 50hz-60hz and down at least to 16hz but 80%-90% of our daily reproduced MUSIC bass range belongs from 60hz/70hz to 30hz and for me this is the main ( other than put at minimum the Doppler effect/IMD ) desired dedicated drivers to bass reproduction and here the phase subs control is way critical. Yes some kind of instruments MUSIC reproduction needs that the subs can works fine from 25hz to 16hz, fine means with absolute aplomb. My Velodyne has usuable 10hz frequency but not so important.

In my latest phase experienced tests I been totally sure about because the overall reproduced sound over all the system frequency range was and is improved in its quality levels as ever before the phase subs change and was only this parameter the one I touched in the subs : same volume, same crossover point, same everything including the subs positions, nothing then but the phase.

Other critical and way important issue when we are integrating subwoofers in our MUSIC system is to have a " rigth " blend " between the sub’s crossover point and the main woofers crossover point.

It has to works exactly as speakers designers do it with his speakers where they choose the rigth crossover frequency of the different filters ( HP, LP, BP ) using normally between first and third order for those filters according each frequency range driver to BLEND . No one use 6 or eigth order filters because the issue is to BLEND and not separates the frequency ranges. Then, this BLEND along the Phase are crucial.

R.