How Close To The Wall Can You Put Your Speakers?

A Guide in Setting up your Home Theater - Andrew Welker explains The Boundary Effect.

How Close To The Wall Can You Put Your Speakers?

How close can you place your speakers to a wall? It's a very good question. But first I'd like to suggest an experiment. If you've got your speakers in that perfect place, you can take some painter's tape and mark the corners on the floor so that you can get them back.

But what I would like you to do is to listen to a track, listen to a recording you know well, then move your speakers, your main front left and right if you have a home theater system, move them right up close to the back wall and listen again to the same track. Now pull them out further, maybe two or three feet ahead of where they were placed originally, and listen again.

I'd love to see your comments before you go forward in the rest of the video and hear what will likely happen if you place your speakers close to a wall. Okay? So try out that experiment, comment below.

Now, the reason that we usually suggest that you should keep at least a couple of feet between a wall, whether it's the back wall or the sidewall and your main speakers, is because we get something, if the speaker's too close to a wall, we get something called boundary loading. And you can think of the wall is acting as an amplifier for the speaker. And you think, well, that's not a bad thing, right? Well, it is because it's not a linear amplifier, which means that only some frequencies will be amplified, others won't, and now you have maybe a nice flat measuring speaker that doesn't sound very good anymore because it's accentuating some frequencies.

So we call this boundary loading, or the boundary effect. And if you get a speaker very, very close to let's say a back wall, what will usually happen is that the mid-bass will pick up, and can get to the point where it starts overpowering other frequencies and not sounding very good.

So that one to two feet rule from the back wall, If possible, if you can live with the aesthetics, is the ideal thing to shoot for. But try it out. The one caveat that I'll mention here is that there are some speakers that are designed to be placed very close to a back wall. Others are meant to be, and designed to be, mounted on the wall. And those speakers compensate for that amplification from the wall in the design of the speaker so you don't get something that sounds out of balance.

All right? Now, one thing to remember is that, although getting close to a back wall usually will just amplify bass, if you get too close to a sidewall, where the wall is now affecting and being seen by the entire front driver assembly in the speaker, now you can actually start amplifying frequencies that are not bass frequencies, mid and high frequencies.

And because they will reflect off that surface and be slightly delayed in time, you can get a very, a blurred unfocused sound. And again, an unnatural accentuation of some frequencies. Think about what happens if you put your hands around your mouth while you're speaking. You can hear that the sound level goes up, but at the same time, you can see that some frequencies are being amplified by that. And the wall boundaries are doing exactly the same thing.

Now, if you absolutely have to place your main speakers close to the back wall, you just can't, you don't have the space or whatever, just remember; if it's a ported speaker, and it doesn't matter whether it's a rear ports or front ports, you can compensate for some of that boundary loading and amplification by plugging one or more of the ports. And we'll link down to a video that I did about port plugs recently, in case you're interested in that.

Now, one final note. The position of the speaker relative to the walls can be used to help in your tuning. If you have the luxury of placing your speakers anywhere you want, relative to the back wall, you can use that to tune the bass loading of the room, and how the speaker's interacting with the room at predominantly low frequencies.

So if the speaker is sounding a little bit thin, and could use a little bit more mid bass, try pushing them a little closer to the back wall. If the opposite is true, and you have a little bit too much bass, and it sounds a little bit overwhelming and overpowering, try pulling them out into the room a little bit more. These tips don't cost you anything, and can really make a huge difference in performance. So I hope that answers the question, how close can I place my speakers to the wall?



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