Wilson Audio Subwoofer Placement

[Ron Resnick]

This is a question for our Wilson Audio experts. I very often see Wilson subwoofers placed in the front corners of the listening room. Attached please see examples of Master Subsonics in the front corners of the listening room. You will notice that they are behind the main speakers.

The Wilson ActiveXO crossover has independent channel phase adjustment, but no time domain or delay adjustment. Often with subwoofer placement we try to line up the voice coil of the subwoofer with the voice coil of the main speaker.

Placing the Master Subsonics in the corners behind the main speakers naturally creates a time delay and increases the arrival time between the output of the subwoofers and the output of the main speakers. The ActiveXO cannot adjust for this arrival time anomaly. It can only adjust phase, which is not a direct answer to the time domain question.

So what is Wilson Audio's thinking here? Is the thinking that if the Master Subsonics are handling just approximately 30 Hz and below the additional few milliseconds of time delay is perceptually irrelevant to our ears at the listening position?

Why not move the subwoofers as close as possible behind the main speakers, or, better still, in situations where there is room on the outside of the main speakers, alongside the main speakers to minimize any difference in arrival time?

 

[Robh3606]

The Wilson ActiveXO crossover has independent channel phase adjustment, but no time domain or delay adjustment. Often with subwoofer placement we try to line up the voice coil of the subwoofer with the voice coil of the main speaker.

Not a Wilson expert:


Why? The room is modal over the entire bass region and with wavelengths that long aligning the phase so it sums "flat" is essentially time domain. I have never seen anyone try to line up VC's especially in a range where the room completely dominates the response. Also goes against the multi sub application, say 4, where you would place around the room on different walls.

Typically powered subs are subs really doesn't matter who makes them and all have identical placement issues unless they are cardioid or dipoles or have an atypical response pattern with nulls or shading.


Rob

 

[sbnx]

This is a question for our Wilson Audio experts. I very often see Wilson subwoofers placed in the front corners of the listening room. Attached please see examples of Master Subsonics in the front corners of the listening room. You will notice that they are behind the main speakers.

The Wilson ActiveXO crossover has independent channel phase adjustment, but no time domain or delay adjustment. Often with subwoofer placement we try to line up the voice coil of the subwoofer with the voice coil of the main speaker.

Placing the Master Subsonics in the corners behind the main speakers naturally creates a time delay and increases the arrival time between the output of the subwoofers and the output of the main speakers. The ActiveXO cannot adjust for this arrival time anomaly. It can only adjust phase, which is not a direct answer to the time domain question.

So what is Wilson Audio's thinking here? Is the thinking that if the Master Subsonics are handling just approximately 30 Hz and below the additional few milliseconds of time delay is perceptually irrelevant to our ears at the listening position?

Why not move the subwoofers as close as possible behind the main speakers, or, better still, in situations where there is room on the outside of the main speakers, alongside the main speakers to minimize any difference in arrival time?

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Phase is time. By adjusting the ActiveXo's continuously variable phase you are looking for the setting that aligns the waves. The wave will always be at least one wavelength behind the main speakers unless you position the subwoofer well in front of the main speakers. The reason why is the same reason that putting the subwoofer right next to the speaker still does not time align them.

The subwoofer has phase and group delay. So even if you place the subwoofer next to the main speaker the wave will be out of phase with the main speaker (at 0 degrees phase). Ported subwoofers have much worse group delay compared to sealed subwoofers. Ported subs are typically in the 20-30ms range while sealed subs are typically less than 10ms.

 

[Tangram]

I’d be surprised if any of those setups are acoustically optimized. They are very large subs. Tucking them in a corner appears to be for aesthetic considerations. Maybe someone with direct knowledge of these rooms can chime in.

 

[microstrip]

I’d be surprised if any of those setups are acoustically optimized. They are very large subs. Tucking them in a corner appears to be for aesthetic considerations. Maybe someone with direct knowledge of these rooms can chime in.

Can't refer to systems I don't know about. When setting the WAMM Master Subsonic in our distributor the position was optimized with the help of measurements. Someone it the factory was online considering them and also advised on their set up. Many times subs are placed in corners in order to be as far as possible from the main speakers, avoiding creating similar resonances in the room and getting room gain at different frequencies.

 

[sbo6]

Some great advice here, encouraging. My thoughts

- Rob's post above is spot on.
- Phase control is a delay in degrees (time like Todd said) versus the original signal. However, between the different mains and sub's amplifier circuits and more importantly, the significant effects of the room on your primarily omni-directional bass, plus our human inability to discern LF quarter / half wavelength differences, aligning speakers and subs at the same voice coil plane, if you will, is a fool's errand. Also, if your objective is to ameliorate bass modes at the listening spot, why would you locate subs at the mains further exacerbating the mains' woofers - driven room modes? People put subs like the Rel 6 pack next to mains for eye candy, not ear candy (and Rel's salesmen tell you to put them there either for eye candy and / or their own woofer integration ignorance). Unless your room is truly a large where room mode effects are minimal (which is none of us) at the listening spot, subs next to mains is a sonic no - no.

 

[Lee]

I can speak to this, at least partly. I have done several LoKe subwoofer setups and the ideal placement tends to be 2-6” (usually 4” is the best) away from the main speaker raked to an angle of the main speakers woofer, and a phase degree of 6-11 depending on type of amplifier, usually 6-7 for tube gear. You dial them in based on a click track.

The larger Chronosonic style woofers are designed to be placed on the corner back wall but similar setup procedures apply.

 

[Lee]

Usually a 40 hz tone and a 40 hz click track are used to set phase. The clicks become a solid thump when the phase angle is optimized.

 

[Lee]

Some great advice here, encouraging. My thoughts

- Rob's post above is spot on.
- Phase control is a delay in degrees (time like Todd said) versus the original signal. However, between the different mains and sub's amplifier circuits and more importantly, the significant effects of the room on your primarily omni-directional bass, plus our human inability to discern LF quarter / half wavelength differences, aligning speakers and subs at the same voice coil plane, if you will, is a fool's errand. Also, if your objective is to ameliorate bass modes at the listening spot, why would you locate subs at the mains further exacerbating the mains' woofers - driven room modes? People put subs like the Rel 6 pack next to mains for eye candy, not ear candy (and Rel's salesmen tell you to put them there either for eye candy and / or their own woofer integration ignorance). Unless your room is truly a large where room mode effects are minimal (which is none of us) at the listening spot, subs next to mains is a sonic no - no.

I’m personally skeptical of the REL six-pack regardless of placement. It definitely creates room acoustics issues in my experience.

Also, I politely differ on subs next to mains. I can tell you with certainty that it is correct for Wilson Audio speakers.

 

[Ron Resnick]

I’m personally skeptical of the REL six-pack regardless of placement. It definitely creates room acoustics issues in my experience.

With six subwoofers to play with I am sure the swarm aficionados would be much happier distributing them around the room.

Also, I politely differ on subs next to mains. I can tell you with certainty that it is correct for Wilson Audio speakers.

Sorry which is correct for Wilson Audio speakers?

I assume you mean placing the subwoofers other than next to the main speakers?

 

[Elliot G.]

Gobel Divin Sovereigns are phase adjustable in 1 degree increments from your chair BTW

 

[Ron Resnick]

Gobel Divin Sovereigns are phase adjustable in 1 degree increments from your chair BTW

And they have a time delay adjustment!

 

[Porsche]

Wilson needs to learn to build a full range speaker with bass, absurd if you have to buy subwoofer towers for a full range speaker this size and cost

 

[Ron Resnick]

Wilson needs to learn to build a full range speaker with bass

How many times have you heard the XVX? That is a full range speaker that does not require subwoofers.

absurd if you have to buy subwoofer towers for a full range speaker this size and cost

It is pejorative of you to suggest that "you have to buy subwoofers." As somebody who would add subwoofers to a ham sandwich, there are loads of legitimately full range speakers to which I would add subwoofers.

Other than in small listening rooms, perhaps, my general view is that regardless of what are the main speakers is it is possible to figure out something beneficial on a net basis to do with subwoofers.

 

[sbnx]

Subwoofers belong where they have linear output in the range they will be used. If we want to re-inforce bass from 15-35Hz then we need to find a location that does that and also doesn't have excess energy higher up. If the subs can be placed next to the speaker and they accomplish this goal then great. If not then look for a position elsewhere.

 

[Porsche]

How many times have you heard the XVX? That is a full range speaker that does not require subwoofers.


It is pejorative of you to suggest that "you have to buy subwoofers." As somebody who would add subwoofers to a ham sandwich, there are loads of legitimately full range speakers to which I would add subwoofers.

Other than in small listening rooms, perhaps, my general view is that regardless of what are the main speakers is it is possible to figure out something beneficial on a net basis to do with subwoofers.

I didn't suggest anything, the speaker above has dual woofer towers, that's silly unless the owner is a bass head. an yes, I have heard the xvx and they do lack in the lower octaves IMO as do many large full range speakers. unless you are in an enormous room and or listen to organ music 99% of the time its overkill IMO

 

[Ron Resnick]

I have heard the xvx and they do lack in the lower octaves IMO

unless you are in an enormous room and or listen to organ music 99% of the time its overkill IMO

Sorry, but I am confused.

 

[bonzo75]

Sorry, but I am confused.

When I read this in Latest Activity I initially thought you were on your thread

 

[Elliot G.]

And they have a time delay adjustment!

they have everything to integrate them and get maximum results. Adjustable phase in 1 degree increments allows for perfect timing . This is available in the latest software for a about a year

 

[Elliot G.]

How many times have you heard the XVX? That is a full range speaker that does not require subwoofers.

and yet every time you see them it has subs? things that make you go HMMMMMM LOL