Where are the subs?

Hello dbphd,

     I'm glad you're enjoying your system so much in a new room.  However, I believe your initial experiences in your new room are more a fortunate combination of factors than something you can rely on experiencing on a consistent basis with a larger sample size of source material.
      Your  Kef Ref 1 monitors, I'm assuming on speaker stands, are excellent speakers with exceptionally good bass extension for a monitor type speaker of about 40 Hz.   As you know, The Bach Toccatta and Fugue BMV565 has deep organ notes that likely require the full bass extension of the Kef's bass drivers at times.
     I would highly recommend utilizing your Velodyne HSG-10 subs and your xover in your system.  Not only because you'll be gaining the capacity of high quality bass reproduction of most of the bottom octave in any music (16-32 Hz) but also because you'll be relieving the Kefs of the burden of trying to reproduce bass frequencies at their woofers' physical limits of about 40 Hz.  
     There's also the added benefit of relieving your amp(s) from needing to supply the significant power the Kefs would demand when attempting to reproduce bass frequencies near their limits.  You'll notice the Kefs have an improved sound quality performance from the mid-bass through the midrange and treble with a greater sense of effortlessness when you add your subs and xover back into your system.
     You may also notice overall system performance improvements by raising the low-pass cutoff frequency a bit.  
   
     If you'd like state of the art bass response in your new room, utilizing 4 subs in a distributed bass array configuration would provide it.

Tim
  

Hello dbphd,

That’s perfect! Get the 2 HGS-15s repaired and prepare to be amazed. If you’re using this room for ht and music, using all 4 positioned in a distributed bass array(DBA) will provide sota bass response for both.
This DBA concept works extremely well in virtually any room and with any pair of main speakers. I assure you that the results will stun you.
I use an Audio Kinesis Swarm 4-sub DBA system in my 23’ x 16’ foot room for both ht and music and it’s been a true revelation how well it works for both. Here’s an Absolute Sound review of the Swarm system that describes the performance improvements it provides very well:

https://www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/

Since you would be using a custom DBA system with four self amplified subs with individual settings for volume, xover frequency and phase, the proper positioning and settings configurations of each sub would be a bit more complex and time consuming but well worth the effort.
You also have the option of just purchasing a complete AK Swarm 4-sub system for $2,800 if you don’t want to bother getting your 2 subs repaired. The system consists of four 4 ohm subs with a 10" aluminum long-throw woofer that are each 1’wide x1’deep by 28"tall and weigh 44 lbs. A 1K watt class AB sub amp/controller is also included that allows for setting the volume, xover frequency and phase of all four subs as a group.
These relatively small subs would be positioned around the perimeter of your room with the drivers facing and just a few inches away from the wall. Each sub has spikes and the speaker connections are on the bottom. This improves the WAF since they look like solid wood pedestals or end tables when viewed from inside the room. My room has a crawl space below so I cut a small hole underneath each sub and was able to have no speaker wires visible.
But either with a complete kit DBA or a custom setup, I know you’d be thrilled with the results.
If you’d like to learn more about the DBA concept, just google ’distributed bass array system’. Those written by Dr. Earl Geddes and Dr. Floyd Toole will provide the most scientific and detailed explanations of how and why the concept works so well.


Tim

audioman58,

     No single sub, no matter how good or expensive, can compete with the bass performance of a 4-sub distributed bass array system.  Even a pair of top quality subs will not match the performance of a 4-sub DBA system.  
     Since dbphd has a 100" video screen in this room for ht, I think it's safe to assume he has multiple seating positions in this room for friends and family enjoying ht together with him. 
     It's possible to optimize bass response using a single sub but only at a single listening position and the bass response will be poor at most other positions in the room.  However, a 4-sub DBA system would provide excellent bass response throughout dbphd's entire 14' x 19' room.

Tim

Hello wspohn,

     I'm just curious what source material you use that contains organ music with bass extension down to 16 Hz?

Thanks,
  Tim

Hello dbphd,

I think you made a great decision by opting to give the DBA concept a tryout in your new room. I’m retired and have the time and interest in assisting you if you’d like. I just have a few questions for you:
I know you’re using the Kef Ref 1s on speaker stands in your new room but do you also own a pair of Kef Ref 107/2s?
Does your new room have wall to wall carpeting?
Is there anything located below this new room-basement, crawl space, another room?
Have you decided on whether you’re going to have your HGS-15s repaired and create a custom DBA system or purchase and utilize a complete DBA system kit like the Audio Kinesis Swarm for $2,800?
     As I stated previously, either a custom DBA (consisting of two 15 and two 10 self amplified subs) or the complete kit Swarm DBA ( consisting of four 10" passive subs and a sub amp/ control unit) will provide excellent bass response in your room that will extend down to 20 Hz.
     However, I think you should be aware right from the get go that the custom DBA setup and configuration will be more cumbersome, elaborate and time consuming than the Swarm DBA setup would be. This is due to the individual configuration of the volume, xover frequency and phase necessary on each Velodyne sub as compared to the single configuration of setting these controls once on the Swarm for all 4 subs as a group. Remember, this is a trial and error process in which you will set the volume and xover identically on all 4 Velodyne subs, listen and evaluate, make small adjustments and keep repeating this process until you're thoroughly pleased with the results.  This process would be the same with the Swarm DBA system but the fine adjustments to the settings would be much more convenient.

     larry5729 stated: " I don’t want to hear a boomy bass sound take over my system. I just want to hear all of the frequencies available on a recording. There is a lot of music recorded that gets down below 24 Hz and I want to hear it. I will try to set up my subs at low volume so they will not stand out and blend with my towers."
Some good points. The bass quality produced by a 4-sub DBA system is the opposite of boomy, it’s very detailed, smooth and natural but, when the content dictates, the bass can also be very powerful,dynamic, impactful and felt as well as heard.
     Overall, I perceive a sense of effortlessness, naturalness and ease to the bass response of the 4-sub DBA system that I believe is due to two facts: 1. There are 4 subs contributing to the total bass output, not just 1 or 2, and no single sub is being driven anywhere close to its limits, and 2. There is constantly a large reserve of power available to deliver powerful bass impact and dynamics instantly as the content requires. I never have the sense the bass system is being taxed, stressed or even close to clipping.
I’ve had my Swarm DBA in my system for about 4 years now. I’ve been consistently amazed by the amount of sonic content that exists in the 20-40 Hz range and how satisfying it is to hear and feel it reproduced in high fidelity. Of course, I knew it existed and was important on music and movies but it was a bit stunning to discover it also exists in abundance on my Xfinity cable hd tv broadcasts and even on numerous tv commercials. It’s just a bit of added fun.
     I’ve learned that the key factors in seamlessly integrating a 4-sub DBA system with my main speakers were the proper positioning of all 4 subs and the setting of the volume and xover frequency precisely on the sub amp/control unit. The precise setting of the volume and xover frequency proved to require a lot of trial and error experimentation and was the most time consuming portion of my DBA setup and configuration, even though these controls only need to be set once on the sub amp control unit for all 4 subs.
     My goals were to not constantly hear the bass contributions of the DBA system and for it to only be active when the music or ht content required it. I was also aiming for the bass from the DBA’s four 10" dynamic cone drivers to blend or integrate seamlessly with the full range output from my Magnepan planar-magnetic main speakers, which are very fast and detailed but only have bass output that extends down to 35 Hz. My experiences using 1 and 2 subs was that the bass seemed to lag behind my main speakers and the bass seemed to be disconnected. I found the Swarm sounded best integrated in my system with a xover of 40 Hz, a bass volume of just under 50% with all subs run in mono and configured as ported (with the port plugs removed).
     I sometimes find it a bit difficult to accurately describe just how exceptionally close to a state of the art bass system a properly configured DBA system actually performs but I’m very confident it would only take a single in-home audition in their system and room to convince virtually anyone.

Tim

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

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

dbphd:
    "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."

Hello dbphd,     
     Millercarbon , clio09 and myself all have experience using 4-sub DBA systems in our rooms and know there's absolutely no need for mics, room correction or bass room treatments.
     However, it seems you're determined to use the SMS-1 with room correction in your new room.  I agree with clio09 that you should use what you're comfortable with but I'm not as confident as clio09 that you'll accomplish the same results from either a DBA with no room correction and a master SMS-1 for your two 15s and a slave SMS-1 for your two 10s (see the bottom of page 10 on your SMS-1 manual for setup instructions on this).
     As I stated on my last post:
     "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."

      However,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.  
     The reason I'm skeptical is because it seems to me that the two methods would be working against one another.  The DBA concept is based on producing numerous more bass peaks and dips in the room while the SMS-1 room control concept is based on reducing as many bass peaks and boosting as many bass dips in the room as possible.  
     I hope the net effect of this dueling bass response concepts results in an overall positive result but, having no experience using both at the same time, I really have no idea what the results will be.
     Hopefully, you'll have your two 15s repaired by the time the experienced clio09 arrives for a visit and you guys can figure out a good solution.  I'd love to join in and help out but I'm in Indiana and have no plans to be in L.A. anytime soon.

     Good luck and please repost here detailing how things worked out.

Thanks,
  Tim

dbphd:
"As I’m sure you’re aware, an SMS-1 emits a series of pulses through the subs that are captured by its microphone, evaluated, and equalization applied that mainly cuts peaks without amplifying valleys. The process can be for one or multiple subs, so I see no downside in using it. On the other hand, the SMS-1 remote includes an equalization defeat button making it trivial to try the array both with equalization and without."

Hello dbphd,

     I have been looking through the SMS-1 manual.  I was under the impression its corrective equalization did both, cuts bass peaks and amplifies bass dips or valleys.  I'm not saying you're wrong, it's just that I remember a section warning that trying to correct dips/valleys of -6 Db or more could result in overdriving or stressing a sub. But now that I'm thinking about it, it could have been referring to manual adjustments and you could be right that the automatic equalization will not attempt to amplify dips/valleys this large.  
     If this is true, I think it's a positive factor in determining how well a 4-sub DBA and MS-1 combination will actually perform.  I'll leave it to you and Tony to figure out.
     I've just started reading the manual section, starting at the bottom of page 10, on  using multiple subs and how to utilize multiple SMS-1s in a master-slave configuration.  You owning multiple SMS-1s could be very useful.  
    I'm currently thinking connecting both of your 15s on one SMS-1 as a master and connecting both of your 10s on another SMS-1 as slaves might be the best way to set your system up.
     I've also been thinking about the best method for distributing your subs in your 19' x 14' room.  Can you tell me which wall you have your 100" screen mounted on, a short wall or long wall?  And whether you're willing to move the screen and reconfigure your room if it would result in improved system performance?
     Here's an example explaining why this could be important.  You guys may discover that the bass sounds better in your room with the 15s positioned about 8' apart along a 14' wall than along a 19' wall.  The reason could be as simple as the very long deep bass soundwaves (a 20 Hz wave is about 56' long, a 30 Hz wave is about 38' long and a 40 Hz wave is about 28' long) require an extra wall reflection for the entire length of the complete soundwave to exist in the room and be processed by our brains as a deep bass tone.  The 56' 20 Hz soundwave would be launched from the front 14' wall and need to travel the length of the room's 19' length, reflect off the rear 14' wall, travel the 19' length of the room again and reflect off the 14' front wall and travel another 18' toward the rear wall before our brains even process this now complete soundwave to be recognized as a 20 Hz tone.  This is just sort of 3 reflections for the soundwave to be heard.  If the sub was placed along a 19" wall, the same 56' long 20 Hz wave would require almost exactly 4 reflections to be heard. 
     Will this make any difference in the perceived bass quality either with or without room correction?  I'm not sure but you guys will probably be finding out.
    The ability to turn the SMS-1's equalization on or off as a remote function is extremely convenient and another positive factor in determining just how well a 4-sub DBA and multiple SMS-1 combination may actually perform.  
     Things are certainly looking good.  The results should be very interesting. 

Thanks,
   Tim 

dbphd:"Tim, the speakers are on the 14' wall, an HGS-15 in each corner, an HGS-10 behind each speaker.  The carpet on the wall and ceiling are for video projection, not audio."

Hello db,
     That's all good news since there's no need to reconfigure your room's video or audio orientation.  Interesting you use carpet for video projection.
      Another decision you and Tony need to make is the best positioning and distribution of your two 15" and two 10" subs in your room.  I thought it might be useful for you guys to know the details of how I positioned my 4 subs in my very similar sized room (23'x16'), with my main speakers and video display also along the short wall in my room,
 and then include some final advice.  An important difference to keep in mind is that I have four identical 10" subs and you'll have two 15" and two 10" subs.

Here's the setup procedure I used:

1. Disconnect the main speakers

2. Sub#1 is hooked up and placed on its back (driver facing the ceiling) at the normal listening position. Music is played that has good and repetitive bass.

3. Walk around the perimeter of the room, starting at the front right corner of the room and walking counter-clockwise, to]determine exactly where the bass sounds best to you (most accurate, detailed and natural).

4. Place sub#1  at the spot you determined the bass sounded best.

5. Sub#2 is hooked up and placed on its back at the primary listening position. With sub 1 & 2 playing, continue walking from sub#1 around the perimeter of your room counter-clockwise to determine the next spot where the bass sounds best to you.

6. Place sub#2 at the spot you determined the bass sounded best.

7. Repeat this procedure for sub#3 & #4.

Small positioning adjustments may need to be made for each sub due to avoiding furniture and the WAF.

8. Once all 4 subs have been positioned, reconnect the main speakers and verify the sound is to your liking.  If not, start over from the beginning.                                                                                                                     

     Since you're setting up a custom DBA system, utilizing two 15" and two 10" self-amplified subs rather than my four identical 10" subs, there's a need for you and Tony to decide the specific order of positioning your subs; there are multiple options:

Option1: Position your two 15" subs first as subs #1+#2 and your two 10" subs last as subs #3+#4.   This option would likely result in the two 15" subs placed near the front of your room and the 10" subs near the rear of the room.

Option2: Position your two 10" subs first as subs #1+#2 and your two 15" subs last as subs #3+#4.   This option would likely result in the two 10" subs placed near the front of your room and the 15" subs near the rear of the room.

Option3: Position your 15" and 10" subs in an alternating pattern starting with a 15" sub as sub#1, a 10" sub as sub#2, a15" sub as sub#3 and a 10" sub as sub#4.  This option would likely result in a 15" and a 10" sub placed near the front of your room and a 15" and a 10" sub placed near the rear of your room.

Option4:Position your 15" and 10" subs in an alternating pattern starting with a 10" sub as sub#1, a 15" sub as sub#2, a10" sub as sub#3 and a 15" sub as sub#4. This option would likely result in a 15" and a 10" sub placed near the front of your room and a 15" and a 10" sub placed near the rear of your room.      

    If you and Tony don't feel up to moving your heavy subs around to try all 4 options, I wouldn't blame you. My opinion is that option1 has the best chance of working well.  You could place both 15"s along your front 14' wall, one at each end and below your video carpet.  Place a 10" on each 19' wall on either side of your listening seat and about the same distance back from the front 14' wall as your listening seat.  The 10"s may also work well on opposite ends of the rear 14' wall,  with each 1-2' in from the corners.

    Another configuration I think would likely work well is a 15" sub in the middle of each of your front and back 14' walls and a 10" sub in the middle of each of your 19' side walls.

     I'd  avoid placing any of your subs in a corner.  They'll produce more and louder bass in corners but avoiding corners, even by 1-2', will produce higher quality bass. 

Tim

Good Morning DB,

     If you and Tony don't screw things up, anything that sounds good now will only sound better with a 4-sub DBA SMS-1 bass system incorporated.  You'll hear Price/Vickers Aida sounds even better, with all the musical content from about  20-40 Hz you were not hearing suddenly mixed back in and reproduced in high quality and with seamless integration with your Ref 1s...……….IF you and Tony set the volume and crossover frequency just right, which most likely means as low as possible without compromising bass impact, bass dynamics and seamless integration.


No pressure,
    Tim