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[Mike Henderson]

Luke,

The distributed subwoofer method is based on solid acoustic principles, and works well for bringing a more spatially uniform response, which can then be EQ'd overall to produce the desired results.

It's not just "boom at X location". It's even response at all locations.

You seem to think physics = snake oil, and that just ain't so.

Chris

Thanks for all of the info guys. Yes Chris the ideal goal would be to get even response at all locations but if not possible with all of the things in the garage closest option would be to  get "boom around where we sit". Actually I was thinking the same thing Luke mentioned and try to do some experimenting.

I can get one more sub and move it around to different spots where we sit to see if it will help. Klipsh has a wireless sub which would make this easy and should it not work I can simply send it back.

[John Schalk]

I can get one more sub and move it around to different spots where we sit to see if it will help. Klipsh has a wireless sub which would make this easy and should it not work I can simply send it back.

That is the recommended way to locate a sub for home theater applications.  At least, that's the first step in several subwoofer manuals that I've read recently.  I've added subwoofers to two systems in my house recently.  In both cases, the sub's location was more or less pre-determined.  For the basement workout tunes, the sub is in a corner behind the TV stand.  I can hear room modes, but since I'm moving around when I exercise, it sort of evens out.  I flat out got lucky with the sub's placement in the living room / home theater.  It's between the TV and the right speaker and it rattles the room.  It probably helps that my listening position is almost against the opposite wall, so I'm likely sitting in a nice room boundary mode.  And that leads me to my suggestion; if you can locate your listening position near a wall it may help you get a nice full sub sound.  FWIW I wish that I'd added a sub to my home theater years ago.  I thought my full size L+R speakers were good enough, but boy was I wrong about that.

[Mike Henderson]

And that leads me to my suggestion; if you can locate your listening position near a wall it may help you get a nice full sub sound.  FWIW I wish that I'd added a sub to my home theater years ago.

In my experience with subs for Surround, placing it in a corner has always produced best results but since all corners have stuff in them I am first going to try placing the 2nd sub in the middle of the room along the opposite wall. Since we all sit in the middle of the room, this should be best placement.

[Dan Richardson]

Subwoofers in different locations will activate different room modes. If you do the work and testing, you can position them so that the LF response is more even as you move around the room - one subwoofer will fill in the cancellations of another.

I'd consider the above factual, so I'm a little confused about how someone might disagree.

Chris

Happy to disagree. Room nodes are a function of the room, and are source independent. When the room resonances cancel out a specific frequency at a particular point, it doesn't matter how big your subs are or where they're located. +1 -1 is exactly the same as +1000 -1000.

The correct answer to the OP is appropriate bass traps. REW is a solid, free, tool for checking your work.

https://www.hometheatershack.com/forums/rew-forum.8/

[Chris Grimshaw]

Dan,

It looks like you've missed my point. Allow me to try again:

When you put a subwoofer in a room, you get a bunch of nulls at different frequencies and locations in the room..
If you move that subwoofer to another location in that room, you'll get a different set of nulls. Some of those nulls will coincide with the first set, but most will not.

If you use two subwoofers, one in each location:

- In the cases where the nulls coincide, the combined response will still have a null.
- In the places where one subwoofer would have a null but the other would not, you'll still have the output of the other subwoofer: the null hasn't been eradicated completely, but it's a huge improvement as there'll still be some output.


By using a few subwoofers (diminishing returns apply - three or four is usually a good point to stop, but some people go further), and optimising with DSP, it's possible to get an in-room response that's spatially uniform.

Chris

[Luke Geis]

I think perhaps you mixed the concepts of even response and linear response? While Even response does work with distributed sound, it does not bode well for a linear response. When is say linear, I literally mean 1:1, what goes in is what comes out. As we know, if you are not equidistant between two sound sources you get phase interaction. So a PA is " fixed " to achieve the best compromise and achieve as close as is practical, a 1:1 at any given location. When you start loading a room up with subs and speakers with no regard to phase relationship and only to even coverage, you solve one problem and create another. For me, the acoustic principles and physics of distributed subs in a room is bogus snake oil BS, designed to sell you speakers. Does it work, YES, is it right, NO. It cannot ever potentially be 1:1.

Physics cannot be a snake oil, there is nothing to sell from it. It is what it is no matter what you want it to be. So while physics allows you to solve a problem in one way, it doesn't allow you to have your cake and eat it too. Even response is not a linear response. PERIOD. Solid acoustic principles aside, it doesn't defy physics, it simply fills the holes left due to physics. It doesn't solve the phase issues though and it can NEVER be a 1:1, what goes in is what comes out scenario. I would say that with enough processing and time, you could make it so that very specific points in the room could be made to have a linear response, but honestly, with enough time and money, you could do anything you wanted anyway.

As you can tell I am not a fan of the whole Audiophile ideology. When you have people that actually try and justify the cost of speaker cable, power cables, cables risers, and concrete bases 8' thick with unobtanium pyramid point feet and $100 per foot RCA cable, I only see snake oil, because physics don't care bout no $ amount, it is what it is.

[Chris Grimshaw]

Luke,

When you have a setup which has the same frequency response at each listening position, it's trivial to EQ that to give it any response you like, including a linear one.

You have to remember, though, that we're talking about speakers operating in the room's modal region. The standard time-of-flight stuff that you speak of simply doesn't apply here. We're not outdoors - we're in an acoustically small space, and the operating principles are very different.

Chris

[Craig Hauber]

As you can tell I am not a fan of the whole Audiophile ideology. When you have people that actually try and justify the cost of speaker cable, power cables, cables risers, and concrete bases 8' thick with unobtanium pyramid point feet and $100 per foot RCA cable, I only see snake oil, because physics don't care bout no $ amount, it is what it is.

definitely agree, however those people are not the ones worrying about home theater subwoofer(s) placement.
For most of them more than 2 channels is blasphemy.
Many of them also have issues with crossovers in general -read up on the single-driver fullrange fad.
-and then if you can stomach that then move on to the open-baffle concept.
Eventually that would lead you to the few who are convinced that a mono, full-range speaker mounted in a board with no enclosure and powered by output transformerless single-ended tube amp of less than a watt output is the ultimate audio panacea.  (after spending more than we would spend on a whole new PA and the truck to haul it in!)

Back to the HT bass issue,
To me it seems like the whole industry is making the "subwoofer obsession" a little too much like a thrill-ride.  Impact and a sense of power when playing back blu-ray soundtracks is all that matters and musicality and accuracy don't really matter. 
Most of the things I hear in the LFE channel are artificial and synthesized noises manufactured by the film sound creators -and actually gets too monotonous after a while.  (Shutting it off brings a sigh of relief sometimes!)  -I just sat through a transformers movie where it seemed like the LFE went from "cool look what we can do" to "for the love of god just make it stop!"

At least an amusement park thrill ride is over and done in a few minutes! (and you can stumble your pummeled ass to the nearest overpriced drink stand to recuperate)

So if TLDR, just fasten some bass shaker transducers to your couch and quit bothering with trying to recreate non-musical thuds and thumps acoustically!

I understand this thread was more about music listening, so with that in mind why are we trying to achieve good accuracy and coverage with equipment from an industry that's more impressed with a dinosaur foot-thump making water ripples?

[Chris Hindle]

That is the recommended way to locate a sub for home theater applications.  At least, that's the first step in several subwoofer manuals that I've read recently.  I've added subwoofers to two systems in my house recently.  In both cases, the sub's location was more or less pre-determined.  For the basement workout tunes, the sub is in a corner behind the TV stand.  I can hear room modes, but since I'm moving around when I exercise, it sort of evens out.  I flat out got lucky with the sub's placement in the living room / home theater.  It's between the TV and the right speaker and it rattles the room.  It probably helps that my listening position is almost against the opposite wall, so I'm likely sitting in a nice room boundary mode.  And that leads me to my suggestion; if you can locate your listening position near a wall it may help you get a nice full sub sound.  FWIW I wish that I'd added a sub to my home theater years ago.  I thought my full size L+R speakers were good enough, but boy was I wrong about that.

A "trick" I have used a few times.
Put the sub at your seating position, and walk the room.
Where is it "strongest"?
Put the sub there, and go have a listen.
Chris.

[Luke Geis]

The modal region, indoor-outdoor stuff is trivial. You can make your room be close enough to an anechoic space to make it a non-issue if you spend enough time and money. If you have a room treated well enough, most of the issues with room modes and modal regions are eliminated. You see where this is going.

Room treatment is not a very practical solution for a garage though. This is why I mentioned the dispersed sub concept. It is a solution to his problem. I also pointed out my reasons for not employing that solution.

As it pertains to the audiophile world, there are only a few concepts that they lean on which are truly supported by physics. The rest of it is clever nomenclature and weird science that physics doesn't substantiate. I'm not saying it sounds bad, I'm saying that for a significant amount less, you can have the same and perhaps even better. Bias confirmation aside of course. 

[ProSoundWeb Community]