Help with choosing sub-woofers please


Having survived more than 30 years using full-range electrostatics @clearthinker has finally decided to get sub-woofer(s).  Previously he was put off by the well-known difficulty in setting the cross-over to allow a seamless integration.  Modern sub design and electronic aids seem to have fixed that.

@clearthinker is pretty knowledgeable and experienced in most aspects of two channel audio. He has spent some hours researching sub-woofers but he's having trouble evaluating the benefits of differing design and application approaches.  Such matters are not dealt with qualitatively or comparatively in most postings and videos.  He has yet to listen to any and will be trying contenders in his system.  But it needs to be narrowed down as he can't try them all.

His Martin Logan CLX Anniversaries are -3dB at 56dB and driven by vintage Krell 200 KRS References.  The room is 23 x 15.5 x 8.5 feet, carpeted, plaster ceiling, All walls are deadened with French style fabric covering and 25mm of wool behind.  Symmetrical, no windows.  No furnishing save equipment, two chairs and a small side table.  Subs will be spiked to concrete floor.  @clearthinker  listens to two channel stereo all genres, no theatre in this room.  Cost is not the most critical issue.

Some of the issues that need evaluating (in no particular order) are:

*  Benefit of subs using two opposing drivers to reduce vibration, rock and roll

*  Floor firing vs. side firing

*  How much does size matter?  Small is better if all things are not too unequal

*  Benefit of two subs to create stereo image.  Many say bass isn't very directional below about 50Hz.  But bass heard above that on the MLs is certainly directional

*  To what extent will the sound deadening deal with room modes?  Some say bass waves go straight through wall treatments back to the hard surface behind and bounce right out again

*  Benefit of two subs (or more?) optimally arranged to cancel room modes.  The unlamented Miller who was rude but knew a fair bit about audio used to mention six and eight.  There is freedom to locate.

*  Taking unit price into consideration, is it better to have one hi-end sub, two decent ones or multiple smaller cheaper subs to deal with room modes?

*  Do wireless feeds work well or is good old wire better?  How much does wire  choice matter in feeding subs (that may be a long way from the amp.  Incidentally the Audio Research Ref 6 is fully balanced.

*  Is the KEFKc62 too good to be true?

*  Does it make sense to keep it simple and just to use ML subs and digital set up systems with ML main speakers?  If so, is it worth spending more to get the Balanced Force series?

*  What about REL?

*  Anyone else?

 

Thanks in advance for all your posts.  I'm hoping a discussion of qualitative and comparitive issues  will help others get to the bottom of optimal sub-woofer applications.

 

128x128clearthinker

@clearthinker

Yes this video was more like the ones we record at our DIY meets but I believe he was talking about constrained layer dampening for bass which according to his comments later in the video do provide bass dampening.

This video was from 2013 almost 10 years ago. Before you make a judgement you should know who this guy is. Dr. Geddes (PHD in acoustics) has done extensive research, real scientific research on how we perceive sound, environmental reaction to sound and wave guide design. He and his wife worked together to design experiments to actually measure perception. I just saw another video regarding THD and how our perception of it varies at different volume levels and what harmonics we can detect and which ones are masked by the way our ears work. This reinforces my theories that measurements don’t really mean that much because we’re measuring the wrong stuff but I always like the people who agree with me more than those who don’t.

Dr. Geddes is now out of the stereo biz and makes stained glass windows but I bet his stereo sounds really good while he’s doing it.

Cheers, and good luck

 

Quested Subwoofers from the UK, Studio Accuracy at its best and easy to intergrate using a analog crossover control or DSP if you into DSP.

I added a second Rel this weekend and I'm very pleased with the improvements in in the depth and smoothness of the bass. Seems like the whole soundstage is more cohesive. I was going to sell my speakers and single sub and buy speakers with built-in subs but what I was interested in weren't available to listen to. Good for me. Too bad for them.

@danager   Thanks.  Yes near the beginning of his talk he said he has an acoustics PHD.  Most of what he said makes sense, but he was totally contradictory on the benefits of conventional room boundary damping for low frequencies.  My room is built so I can't alter it now.  Looking into constrained layer damping, it is said the effect is gained by attaching two different materials to each other, even though these may be relatively thin.  Other vids have suggested that short of mounting walls on springs (not very practical, it is impossible to damp low frequencies.  One said you need 5 feet thick material to damp a rear wall.  Not very practical either.

@dalims4     Noted.  Did you wire the two RELs separately for stereo or wire both sides into both?   And where did you site them in the room?

@clearthinker you are correct regarding passive bass dampening it's not a practical  strategy.   Nelson Pass made an active dampener that would listen and then apply a 180 degree phased mirrored sound to compensate much like noise cancelling headphones but it either didn't work or was never marketed correctly but I like the concept as it could easily be place in the rear of the room without the hassle of running wires or futzing with wireless connections.