Help with choosing sub-woofers please

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

At 80Hz the waveform is 14 feet long.

The ear cannot know the sound is there until the entire waveform has gone past it.

It cannot sort out the frequency until 2-3 more iterations. By this time the waveform has bounced off of the rear wall (unless you have an enormous room!) and is making its way back- and has probably already passed the listening chair by the time you can even tell what the bass note is.

So in most rooms anything below 80Hz is entirely reverberant. So its not directional at all at 80 Hz, let alone 50Hz.

The other takeaway: if you have a room with the wall in front being roughly parallel with the wall behind you, there will be standing waves no ifs ands or buts. This is why there can be good bass everywhere in the room but the listening position, and this cannot be treated with room treatment or room correction.

If a standing wave is cancelling bass at the listening position, you could put 10,000 watts worth of correction at that frequency and it would still cancel.

This is why multiple subs (Distributed Bass Array) works. If properly placed (asymmetrically in the room) they will break up standing waves, resulting in evenly distributed bass throughout the room.

Audiokinesis http://www.audiokinesis.com makes a subwoofer system called the Swarm that is 4 subs meant for this purpose. Unlike most subs, they are designed to sit directly against the wall, taking advantage of the room boundary effect. This allows them to be more compact and easier to place, especially if space is limited. I have Swarm subs in my system- they work a treat!

The trick is to keep their output below 80Hz so they don’t attract attention to themselves. Stupidly easy to set up too.

How many times do we hear this one?

((((They need a VERY large room. Most homes don’t have the kind of space they need. They sounded best out a good ten feet from the back and side walls.))))

One of the best solutions we have found is a pair of Vandersteen Sub3s

They offer a unique solution for every room with its non DSP adjustable analog tuning from 22 hz to 130hz on each channel. One of the Martin Logan dealers at the time ran a pair of Vandersteen High Pass filters and Vandersteen Subs achiving fantastic results and got best sound at show with CLS. We have also sucsessfully paired many pairs of Vandersteen subs with Magnepans and other planar speakers

Taking full advantage of their unique High Pass/ bi amping allows lower distortion in the main panels or any speakers, dramatically improving the clarity and transparency of the whole system, while tuning out unwanted heavy bass that overloads most all rooms. This for me has always been the best solution. .

Best JohnnyR

Audio Connection

Vandersteen dealer

and if you want, you can always swarm the vandersteen subs. Also, it’s Stereo 101 to NOT place the listening chair in a mode…..

When housekeeper moves my chair back 6” towards the wall, my ears let me know she has been here…..

Best to all

Jim

Thanks y'all.

@danager     Early in his vid Mr Geddes says damping all the room boundaries is good for bass.  Then just after 17m he says it won't do any good at all.  Kinda put me off him, that and his whiny voice and condescension, including to members of his audience.

@avanti1960    Methinks you protest too much about REL.  They are good subs and already on my shortlist.  Do you represent them at all?

@atmasphere   The Swarm looks interesting in principle and good value.  Putting in 4 subs to cancel room reverberation is a bit like herd immunity.  I suppose 'herd' = 'swarm'.

But why are they two feet tall?  What's the other half of the cabinet doing?  They're not really 'compact' at 23x12x12 inches.  Why do we have to have old-fashioned wood veneer finishes?  Why don't they quote the frequency range between dB limits?  And, as @tomic says, any small sub can be 'swarmed'.

@atmasphere   The 14 foot wave takes 12 milliseconds to pass my ear.  Is that fast or slow?  My MLs are flat at 80Hz and the bass there is pretty tight, not an unrecognisable reverberating mush.  What's more I can hear it arriving from its source on the soundstage.  I await to hear how much worse it gets at 25Hz.  And whether it's really true my room boundary damping won't make any difference.

@audioconnection    What is it about the design of the Vandersteens that allow them to behave so differently as a stereo pair with essentially the same control systems?

@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