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

Showing 1 response by delm

I had been using a single 15" woofer for about 45 years, either sum L+R or just use R.  Neither are correct as each channel should have a woofer or more. The electronic filter for low pass was 36Hz at 18db per octave.  Full signal went to the Quad ESL 63.

Recently I replaced the single woofer with two JL Audio E112 subs.  The important points here are there is a woofer for channel, the sub has a built in low pass filter currently set at 50Hz, and the signal to the main speakers has a passive high pass single order filter, 3 db down at 80 Hz.  Perhaps other crossover frequencies would be better but that is what I have.  I tried the high pass filter in the E112s, the flexibility would have been nice, but the ESLs are not forgiving to E112 electronics.

You will likely need test gear to setup subs. When I am close I listen to a string bass recording to adjust and confirm.  I use Room Equalizer Wizard software and a MiniDSP UMIK-2 microphone.