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 4 responses by jtcf

IMO the little kef sub(s) would run out of steam in your room. If you end up comparing those to a pair with 12" drivers I think you would hear how the small drivers just can't sound effortless in a good sized room. Same with the rel micros.

My room is smaller and probably not a good comparison, but before a storm knocked them out I had four subs,two 10" and two 12" SVS sealed subs (plus GIK panels) and they did indeed eliminate the worst room mode.Nobel100 who doesn't post much anymore, was my biggest influence to try that.

 Now I have two HSU ported subs that are almost perfect for me. The two things that are lacking are DSP and the ability to vary the phase in increments.Blending them in is simple but they need even more fine tuning. When the low and mid bass are just right regarding tone and texture the vocals are too textural.Tuning it back until the vocals are natural the bass suffers.IME wires and pcs don't seem to make a difference.So now I'm thinking one or two more with DSP and variable phase or start again. Anyway I'm looking forward to the responses here and what you ultimately end up with.

 The Balanced Force subs seem like a great option if you're sticking with ML.

Interesting video, thank you.Hearing instead of reading the facts and theory was really helpful.

@clearthinker the "crawl"  shows you where the bass sounds weak and where it's stronger in your room. It can be heard while standing close to the walls too.When you find the spots that are strongest getting down close to the floor finds the exact spot where the bass is tightest and not muddy.In my room there are two corners with bass build up and the two other corners have nulls.Out of curiosity I placed subs in the spots with the weakest bass firing towards the hot spots,which didn't work well at all. What sounded best to me when I had four subs(sealed) is when the best spots were located, was to place the subs there firing towards the wall.

  The two HSU subs I have now are a different beast and sound better placed along the side walls on either side of the listening position, left firing towards the back corner, right firing towards the front corner(hot spots) with both ports open, Q set at .3,crossover 40hz.Possibly because the steeper slope matches the slope of the speakers. I didn't like the sound when both were sealed or even one of the ports were open.Surprised me, but I'm glad I chose them for the multiple settings to experiment with. I enjoy the tweaking,so I find the thought of the SVS subs with the app intriguing to be able to change the settings from the listening position.