Prescription Speaker Placement


All,

I'm looking for a way to dial in speaker placement to create as accurate a soundstage in my room as possible. I'm hoping to find a description of a piece of music that would help with this, beyond the often used 'dog in the distance' scenario. My ideal would be that the tune is played by a group of five to ten musicians, and the recording and mastering preserved the location of the instruments in relation to the microphones. Someone would then have described the spatial relationship of the players to the mics from side to side and front to back. During playback, the listener would be able to use the description of the location of the players to help place speakers to recreate the positioning of the instruments.

Has anyone come across such a description, or have any related advice? I'm guessing that, in the absence of such a definitive text, a chamber music or similar classical piece where instruments are typically known to be placed might help, but I don't know that kind of music well enough. Any responses would be appreciated. Thanks.

C
128x128cmjones

Showing 2 responses by millercarbon

The method I use is the classic one that has been around for years. I merely refined it to improve precision. But it all starts with figuring out where to put the speakers- and equally important where to sit!- for the best frequency balance.

Two things about that. First, where you sit is just as important as where the speakers go. We have one thread right now with a guy complaining about bass. Look at the picture, he is sitting right against the wall! Well of course you are going to have awful bass sitting right by the wall! Why not sit right in a corner?! So you get the point. Where you sit matters just as much as where the speakers go.

Any normal room there are all kinds of limitations on where things can go. You may be unable to bring the speakers, or the listening chair, very far out into the room. Whatever. It is all about trade-offs anyway and so in that sense these limitations hardly matter.

So, the classical method, starts with speakers and chair somewhere. Hardly matters where. In this phase we are not concerned with image focus or sound stage at all, so forget precision the speakers just need to point sort of the same way. Play music with a good varied bass content, something like Dire Straits Ride Across the River. Listen for a good smooth bass response. The biggest effect on this is distance from walls. So try moving them, a half foot or so at a time, closer or further away from the front wall. Or the side walls. Or both.

Where you sit matters too. So for each speaker location try listening from different places closer or further away. Try not to be too distracted by imaging. We will fix that later. Try and focus on bass response, and midrange balance.

Almost certainly you will find the best sound with the speakers several feet out from the front and side walls, and your listening chair way out into near the middle of the room. This is the basis of prescriptions like the one above, such and such a percent into the room. That is probably about where you will wind up. What I just had you do explains why this is so. It has to do with room boundary reinforcement. Which you just heard when moving everything around, the closer to walls the greater the bass reinforcement. But also the lumpier the bass. Trade-offs. It is all about trade-offs.

Notice your best location for response winds up with speakers several feet from walls, which is also good for imaging! Now with imaging we go back to my first post, to which only one thing to add. There is a tendency to move things a lot, probably because this makes differences bigger and easier to hear. The closer we get to having things dialed in however the more very small changes matter. My speaker placement is within 1/16" and that is why people who hear it always gush about the pinpoint imaging. There’s other things going on but to a large extent anyone can do this simply by following these same steps and being precise about it.

When it comes to toe-in this can be huge. My Moabs were initially set up identical to the prior speakers because I know this is the ideal location for balance. But after a while I began to wonder about toe-in. With very small changes, probably only about one degree or even less, it is possible to adjust imaging to deep and precise or wide and diffuse. A very, very small change can add great depth with these speakers!

This is probably not a question of right or wrong. Straight ahead would be so diffuse just about everyone would say this cannot be right. Even then, notice I said just about everyone. Some will like it. Between straight ahead and straight at your ears is a judgment call.

All of this stuff is a judgment call. The more you do it, the better your judgment! ;)

PS- lostbears, I measure from the walls in my room too. But that is only because I know the room, and the walls. Giving advice on the interzones you never know who has what. Using the string method I have set up systems for beautiful imaging in rooms as diverse as either side of a fireplace in a living room to a large divided screwball walled conference room at CES. It just works.
You don’t need certain music, or any music at all really. The formula for imaging is as simple as everything must be perfectly symmetrical and equidistant.

This is how I set up mine, and everyone else’s, up to and including the speakers in the Talon Audio room at CES. Which I did after several others spent a couple hours laboring in vain. My method took 20 minutes and everyone was happy.

I am going to skip over the initial steps involved in getting the right frequency balance and go straight to what you asked about, imaging. So there is more to it. But in terms of imaging, this is it!

First we get the speakers perfectly symmetrical and equidistant. To do this we tape a string to the outside bottom edge of the right speaker, wrap it clockwise around the base and over to the left speaker, wrapping around and taping it to the outside edge.

If the speakers are perfectly straight ahead then the bases will be perfectly flush with the string. If they are toed in a little then the inside corner will form a gap with the string. Measure this distance. Change toe of one or the other until this is exactly the same on both sides.

Now measure to the exact middle of the string. Exactly half way between the speakers. Use a framing square to go 90 degrees from this mid point. Place your listening chair somewhere along this line. Not half an inch one way, not 1/4" the other. Exactly on this line.

Sit and listen. Pretty freaking amazing, eh? Now, for the final touches.

Listen for image focus, and stage width. Speakers pointed straight at you will image like a laser, but the stage may not be very wide. Speakers pointed straight ahead will produce a much wider stage, but without much focus. I find the best balance with almost all speakers has them pointed at each shoulder, or converging a little behind me. But that is my preference. May not be yours.

Don’t waste your time with recordings. They are all over the map, and cannot be used for this. There are a lot of awfully confused people out there happy to confuse you as well, because misery loves company. Use string, tape, square, and be happy.