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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 3 responses by m-db

m-db's avatar
m-db
937 posts
 

Buy a pair of XLR cables from Mono Price or Blue Jeans cables long enough to circle more than half way around your room. When the cables arrive order at least two sealed app equipped SVS subs which come with a convenient free trial period.

Use one of the subs to Crawl Test map your rooms loudest modes. Locate a sub in the loudest two modes. Follow the manufactures instructions for multiple sub usage. In no time at all you should have a good idea of what suits your low frequency taste.  

Subwoofer remote control = fun. 

 

m-db's avatar
m-db
937 posts
 

[clear thinker]   You and others advocate the crawl test as if all standing waves are bouncing around along the ground.  Surely they are present throughout the room, in which case we should also test whilst standing?  Would save my knees as well.

Your absolutely correct. Crawl Test is a misleading term / title used to search the net for directions and examples. My subwoofer manufacturer suggests the test near the beginning of the setup procedure. 

In my limited experience I usually elevate one subwoofer onto a sturdy table or side table at the listening position. Using the sofa or chair should be fine. While playing my subwoofers included Sweep Tone CD simultaneously through the main speakers and the subwoofer I walk the room listening and making note of the rooms nulls and modes. I measure the modes slightly varied levels using a Radio Shack SPL meter. I found actually crawling the room will yield slightly varying intensities and locations that I consider overkill.

As a result my two twelve inch subwoofers are asymmetrically located in the rooms two loudest modes. They're mounted on MDF platforms with 2 inches of high density foam using extra soft rubber casters rolling on a suspended wood floor.

Since every aspect of every room and system is unique, like speaker placement the Crawl Test is simply a starting point that I've found indispensable for any new installation. Best of luck with your project.

m-db's avatar
m-db
937 posts
 

[JohnnyR]  Its real simple every room is different and the Vandersteen Sub 3s adapt first by not having to play around with DSP processing that also spoils mid range. 

Vandersteen systems provide wonderful results.

Full system Digital Room Correction such as Anthem ARC, Trinnov or Dirac Live can affect the midrange and / or the entire frequency bandwidth. 

Digital Signal Processing subwoofers with onboard automatic processing such as JL Audio, SVS and Velodyne, to name a few, are limited in their high frequency to somewhere well below 200Hz. Even so, many experience an enhanced midrange using most subwoofers not spoiling it.  

Methods of subwoofer equalization / optimization, including the Vandersteen manual EQ vary greatly. Despite these differences its widely accepted in terms of system integration and ones desired low frequency presentation they far exceed those subwoofers equipped with only basic switched crossover and phase selection.

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