Speaker Placement in a Multi-Purpose Room

[AudiocRaver]

Assuming a multi-purpose space, used for home theater and for two-channel listening, what is the best strategy for front mains - Left and Right - speaker placement?

1. Optimize for one type of use and be happy with whatever you get for the other? Ideal two-channel placement might put the L and R in a less-than-optimum position for cinema.
2. Optimizing for cinema might be less than optimum for two-channel listening.
3. Move the speakers back and forth depending on the use of the space?
4. How perfectly does the positioning repeatability need to be if they are moved back and forth?

 

[JStewart]

• Ideal two-channel placement might put the L and R in a less-than-optimum position for cinema.

• Optimizing for cinema might be less than optimum for two-channel listening.

Agree.

• Move the speakers back and forth depending on the use of the space?

• How perfectly does the positioning repeatability need to be if they are moved back and forth?

My first thought is that most who would want to would find it impractical.
I'd say 1/4" tolerance for two channel distance to MLP and between each other. Then there's tow-in angle. Painter's tape on floor might work, haven't ever tried leaving it permanently and testing. A few other potential issues that readily come to mind are damaging speaker wire, cabinet damage during movement, or speakers too heavy to move without a hand truck.

I think it might be possible to have at least very good 2.1 and home theater in most cases with the right speakers and sub(s) placement, married with the choice of screen width and viewing distance.

 

[AudiocRaver]

My first thought is that most who would want to would find it impractical.
I'd say 1/4" tolerance for two channel distance to MLP and between each other. Then there's tow-in angle. Painter's tape on floor might work, haven't ever tried leaving it permanently and testing. A few other potential issues that readily come to mind are damaging speaker wire, cabinet damage during movement, or speakers too heavy to move without a hand truck.

I think it might be possible to have at least very good 2.1 and home theater in most cases with the right speakers and sub(s) placement, married with the choice of screen width and viewing distance.

Our experience is right on with your accuracy suggestion.

While I am sure there are those who do make the cinema/2-channel mains shift to the 1/4 inch-ish tolerances. One negative to the approach is that it inhibits "whim" listening, being able to plop down on a whim and listen to a few songs for fun.

I would like to hear from those who do make the speaker moving work and their techniques for being able to do it quickly with the desired accuracy.

 

[Matthew J Poes]

I don't move my speakers, so I can't speak to that.

I guess I'm wondering, why are these positions different? Why is a home theater optimal speaker placement different from the 2.1 optimal speaker placement? Is optimal based on sound or convenience? I think the two should be the same (I think they commonly arent bust mostly because I think people commonly place their home theater speakers wrong).

In my own setup, which is built as a home theater but for which I did not want to compromise sound quality, I still have the speakers locked in place. My one regret is that I do think that I compromised the speaker placement a little bit. In the end, I wish the L and R speakers were out in the room more and spread farther apart. Because I had to place them inside the area of my 100" screen, they are too close together given my listening seats. Having said that, the room is only 11' wide, so you could argue that the speakers are in the right place given that any farther apart would place them too close to the side wall.

None the less, I'm still feeling that ultimately a compromise is not needed here. My only compromise came from restricting myself to my existing screen. If I was to do this all from scratch, I could have certainly done things differently. I also don't know that putting the speakers out into the room would have been better. They are still 30" from the back wall, so it isn't like they are right up against the wall, and as you know, sometimes speakers sound best in this position, as compared to say 60" out into the room. One of these days I should test, just hate the idea of dismantling the front wall and lifting 100lb speakers.

One thing I'll mention, for those wanting to move around, get good casters. I bought some really inexpensive ball bearing casters for my subs (which I do have setup to move around) and they resonate and vibrate. The balls inside the bearing shake audibly. I ended up replacing them with a better wheel, but it went from a $5 wheel to a $25 wheel. What was an inexpensive little upgrade for convenience turned into a $200 upgrade and ultimately I decided not to add casters to the last two subs, so I can move 2 of the 4 around if I wish.

You might be able to mount a brass plate or other attractive item onto the floor where the speakers should go if you do go this route. I know for me I couldn't live with tape on the floor long term.

 

[AudiocRaver]

I guess I'm wondering, why are these positions different? Why is a home theater optimal speaker placement different from the 2.1 optimal speaker placement? Is optimal based on sound or convenience? I think the two should be the same (I think they commonly arent bust mostly because I think people commonly place their home theater speakers wrong).

You raise an excellent question. Why have two different positions? I can guess a couple of possible answers:

• WAF dictates that the expensive home theater should look nice. Seems reasonable, no? Most likely, such a situation will lead to a clean home theater look, fairly good sound for cinema, and poor sound for 2-channel, unless...
• The mains are temporarily pulled into the room to a more-optimum position for 2-channel listening.
  • except it is a hassle and might just get skipped, with poor 2-channel sound being the result
  • or it might be done hurriedly, with poor results
• With proper discipline and care, the 2-channel position might be really great, and owner might - over time - be able to demonstrate this in such a way that the spouse eventually caves, agreeing that what is good for 2-channel is good for cinema, and then EVERYONE WINS! (my wife says I am a dreamer)

In my own setup, which is built as a home theater but for which I did not want to compromise sound quality, I still have the speakers locked in place. My one regret is that I do think that I compromised the speaker placement a little bit. In the end, I wish the L and R speakers were out in the room more and spread farther apart. Because I had to place them inside the area of my 100" screen, they are too close together given my listening seats. Having said that, the room is only 11' wide, so you could argue that the speakers are in the right place given that any farther apart would place them too close to the side wall.

None the less, I'm still feeling that ultimately a compromise is not needed here. My only compromise came from restricting myself to my existing screen. If I was to do this all from scratch, I could have certainly done things differently. I also don't know that putting the speakers out into the room would have been better. They are still 30" from the back wall, so it isn't like they are right up against the wall, and as you know, sometimes speakers sound best in this position, as compared to say 60" out into the room. One of these days I should test, just hate the idea of dismantling the front wall and lifting 100lb speakers.

Audio, specifically soundstage and imaging (SS&I), is the one realm in the multiverse where any amount of compromise is bad!

Some theater buffs have a hard time accepting the idea that the front-center position is the only one that matters. Trying to widen the sweet spot over several seats, or even rows of seats, is silly. No one but the owner - YOU - cares or appreciates the result, which generally just degrades the bigger the attempted sweet area. Better to make the front-center seat sound GREAT and don't worry about the rest. Then - voila - the 2-channel problem is solved as well.

One thing I'll mention, for those wanting to move around, get good casters. I bought some really inexpensive ball bearing casters for my subs (which I do have setup to move around) and they resonate and vibrate. The balls inside the bearing shake audibly. I ended up replacing them with a better wheel, but it went from a $5 wheel to a $25 wheel. What was an inexpensive little upgrade for convenience turned into a $200 upgrade and ultimately I decided not to add casters to the last two subs, so I can move 2 of the 4 around if I wish.

I tried this with full-range towers once, and the resulting imaging was horrible. Might not be so bad with subs where the wavelengths are huge.

You might be able to mount a brass plate or other attractive item onto the floor where the speakers should go if you do go this route. I know for me I couldn't live with tape on the floor long term.

Or permanent marker spots on the carpet. That's what Sonnie does. It grows on you.

 

[Matthew J Poes]

Ah my carpet is a deep navy blue color so marker wouldn’t show up.

I agree that compromising on speaker position in a manner that compromises the SS&I is bad. I think sometimes the situation can get complicated though. For example, sometimes the best position for imaging causes problems with the bass response and response smoothness. DIRAC can help, but you know how that works, some issues are too significant for DIRAC and some room treatment or repositioning is really better.

I’m any case, I don’t know that I did make any compromises in my own setup. I haven’t tried the other position yet so it’s more a gut feeling. When Dennis came by to listen he noted the speakers might be too close together (which was a concern I had too). I think I could try testing this by sitting closer to the screen for a bit. That would give the same effect.

Wayne do you use any particular ratios or guidelines for speaker placement to get the best SS&I? For example the 1/3 rule (where the speakers are 1/3 from the front wall and 1/3 from the side wall (and thus 1/3 apart).

 

[JStewart]

With proper discipline and care, the 2-channel position might be really great, and owner might - over time - be able to demonstrate this in such a way that the spouse eventually caves, agreeing that what is good for 2-channel is good for cinema, and then EVERYONE WINS! (my wife says I am a dreamer)

Well, I certainly wish you the best of luck with that.

@Matthew J Poes , wouldn't it be nice if you had a processor that would do front wides and then re-assign them to Left and Right for 2 channel?

 

[AudiocRaver]

In Sonnie's home theater, we have determined a "favorite spot" where many of the evaluation models came to rest after the hunt for their best-sounding spot in the room. It is now the first location we will try with a new speaker, a good number of which end up staying right there.

I try to Golden Mean the dimensions in other rooms, but so often there are asymmetries or irregularities that make such a rule unusable.

Good SS&I is an absolute must for me, no exceptions. Aberrations in frequency response are often correctable or can be overlooked easily and eventually forgotten. But SS&I can not be fixed after the fact.

 

[JStewart]

Aberrations in frequency response are often correctable or can be overlooked easily and eventually forgotten.

So long as the frequency response for both left and right are the same (or very close to it) so they image properly?

 

[AudiocRaver]

...So long as the frequency response for both left and right are the same (or very close to it) so they image properly.

Absolute correct, John, thank you for the clarification.