Where are the subs?

Hello avanti1960,

     I agree with you in general that most good quality speakers will benefit by being fed more power from a quality amp.
     However, there's an inherent problem with attaining high quality bass response performance from a pair of tower speakers; namely that the bass, midrange and treble transducers are all fixed in position, typically in a vertical alignment.
     Most owners will position their towers in relation to their listening seat in a triangular configuration, with the speakers 6-8' apart and the listening seat placed carefully at the midpoint between the speakers with the seat positioned at varying distances away from this midpoint depending on owner preference.  The idea being this will provide optimum stereo imaging at the listening seat with the assistance of precise speaker toe-in adjustments.
     This is a fairly effective method for attaining good midrange and treble response and a good stereo sound stage image at the listening seat.  The problem is that the bass drivers cannot be independently positioned for optimum bass response at the listening seat.  This results in your statement, of "Absolutely no need for subwoofers which is the preferred solution IMHO," being an opinion that is not supported by the facts.
     The truth is the bass response performance a tower speaker user attains at his listening seat is dependent on luck.  The odds that two tower subs positioned for optimum midrange, treble and stereo imaging at the listening seat will also provide optimum bass response performance positioned in the exact same position are extremely low. 
     You should consider yourself lottery winner lucky for apparently attaining both with your tower speakers.  The moral of your experience is that you got extremely lucky. I'd suggest refraining from formulating or extrapolating any opinions beyond this fact since they will lack any value.

Tim

noble, I reluctantly gave away the KEF Ref 107/2s because I didn't want to ship them.  The floor is carpeted as is the wall behind the speakers and about 5' of the ceiling above the speakers.  It is a second floor room.  I will try to reconnect the Velodyne SMS-1 bass manager and HGS-10s tomorrow and rerun the acoustic room correction.  For now I'll leave the low-pass at 40 Hz 24 dB/octave without high-pass.  May also connect the Technics SL 1200 Mk 2 and Ayre Pxe phono stage.   

Hi dbphd,

     I hope the recipient of your gift was appreciative of your largesse, quite an impressive gift!
     The DBA concept is designed with either a hard surfaced or a carpeted floor and untreated walls and ceilings in mind.  The free reflections of bass sound waves off room boundaries increase the number of bass modes (bass peaks and dips) in the room and, therefore, are considered beneficial.  I'm not sure if and to what degree a carpeted wall and partial ceiling will effect the performance of a 4-sub DBA system.    My room has full carpeting on the floor but no other room treatments at all.
     I wasn't familiar with the velodyne SMS-1 bass manager so I read this older review:
https://hometheaterhifi.com/volume_12_4/velodyne-sms1-digital-drive-sub-manager-12-2005-part-1.html

     It's an interesting product.  My overall impression is that the SMS-1 and the DBA system have the same goal, to achieve accurate natural and smooth in-room bass response, but through different methods.  It strikes me that the SMS-1 method is trying to simulate digitally what our brains do naturally with the DBA method.  

     The SMS-1 approach is attempting to smooth or even out bass peaks and dips in a room through room analysis using test tones and mics, digital conversion and processing along with parametric equalization.  It's more proficient at reducing bass peaks than boosting bass dips since boosting all bass dips of various frequencies and decibels needs to be done more judiciously to prevent overstressing the sub or subs.
     The DBA approach is attempting to smooth out bass peaks and dips in a room through creating more peaks and dips and relying upon the proven psycho acoustic principle of our brains summing and averaging these peaks and dips which results in a perceived accurate and smooth in-room bass response.  It's equally proficient at reducing bass peaks and boosting bass dips since boosting all bass dips of various frequencies and decibels requires no increased bass output from the sub or subs.
      I'm certain the 4-sub DBA system works like a charm without any mics, room analysis, room correction software or hardware, parametric equalization and room treatments.
     I've never used or heard a 4-sub DBA system configured through an SMS-1 and utilizing room correction so I'm not certain how well this method would work.
    Since I know for certain the 4-sub DBA works extremely well without room correction of any type, however, my opinion is there's no need to complicate the 4-sub DBA configuration and setup by using it.
     If you have the time and inclination, you could try it both ways and determine which setup you prefer.....in the name of science, of course.
     I know from personal experience that using two 15" inch subs is capable of providing very good bass response at a single designated listening position, even without using DSP room analysis and room correction through parametric equalization.
     I don't know whether two 10" subs utilizing the SMS-1's room correction is capable of providing very good bass response at your listening position.  But my concern is that these subs may be overdriven and overstressed if the SMS-1 detects numerous large bass dips(more than -3db down at a frequency) at your listening position.
     Have you made a decision on whether you're going to get your 15" Velodynes repaired or just invest in the AK Swarm? 
    I'd suggest hooking up your turntable and phono stage but waiting until you have 4 subs before bothering with the SMS-1.  I really believe, if you properly position and configure all 4 of your Velodynes in a custom DBA or use the 4-sub Swarm DBA, you'll agree there's no benefit in using your SMS-1.

Tim

Tim, I will have my HGS-15s repaired, but it takes planning. I’m 83, so I need help to put them in the back of the station wagon, then they need to be hauled to LA within a day or so, a two-hour drive from Santa Barbara. I have several SMS-1s, so I plan to us both the HGS-15s and 10s. Running the automated SMS-1 acoustic room correction is easy, but you can spend hours manually tweaking acoustic parameters if you wish.

I’m skeptical of your last sentence. The Ayre preamp connects to the SMS-1 which connects to the subs. I never use subs without acoustic room correction.

@dbphd, the DBA concept and what you can accomplish with your SMS-1 are pretty much one and the same. Use what you're comfortable with or try both and see what you prefer. I have used the DBA concept with 4 subs for a few years now. No room correction was ever part of the equation, didn't feel the need for it. I am trying out a line array concept now that member mijostyn recommended and find this method useful too. IIRC, he uses DSP in his setup, but again I do not. Ultimately I think the use of 4 subs will make a nice difference in your system.

BTW - was at the show in Long Beach yesterday and ran into Doug. Had a nice time. I'll be heading to LA in the next coupe months so I'll try to make a point of stopping by.