Hi everyone I am Dennis from acoustic fields.
Today we are going to talk about some dos and don’ts in room setup. Now a lot of people
have rooms, a lot of audiophile rooms in the last 2 or 3 weeks that I’ve been seeing some
really disturbing trends, I want to bring those things to your attention.
First and foremost, the distances between the speakers and the side wall must be equal.
I mean, this is really no negotiation on this fact. Sound is an electromechanical energy
form and it travels in a constant speed, so we need to have predictability when we have
those reflections coming at us at the listening position. If we have different distances we
have different timeframes, any shifting going on in the sound stage and a dullness and a
grouping, our instruments and vocals suffer, so you wanna make sure our distances are equal.
This is a little alcove in one of our clients’ rooms, so obviously if we did not have that
alcove we would have equal distances. Another thing that’s critical and people are
not seeming to get this for some reason is sound takes on the characteristics of the
surface it strikes. I know that sounds weird, but if sound strikes glass it has a particular
glass sound if you will. That sound is really prevalent in your car, I do not care how many
speakers you have, I do not care what kind of car you have, it is still a problem. It
is still energy inside of a glass bowl. So it’s got a particular sound to it, it is harsh,
it is tinny, it is glaring, and it is like nail on a blackboard, it is something we really
do not want to have. So glass has got to go in our rooms. You’ve got to cover it with
treatment when you’re playing music if you are gonna get any kind of quality sound out
of it at all. Distances equal on both left and right channels
is a must, also no cavities in the room. Because a cavity depending on what its dimension is,
if its 8 foot and it is 2 foot deep, and it is 7 foot high, well it has an acoustic signature.
It has room modes, it has all kinds of the four acoustical distortions, poor diffusion,
speaker boundary interference affect also, and some comb filtering can be going on so
we get a lot of distortioins out of this, what this ends up being a little alcove or
closet that’s open like that, is another speaker, because it is gonna produce a sound based
on its dimensions that it resonates at, and it is going to interfere with our direct sound
from our speakers. So no hidden chambers, no hidden closets, fireplaces, definite no
no, they have to be filled when you’re playing, because they can turn out to be a tuned resonator
that you do not even want, especially with the long pipe in through the chimney.
So distance is equal between left and right channel, side wall reflection points. Obviously
these distances back here are equal, because we need predictability, we need to manage
reflections and manage low frequency pressure, in order to do that we need predictability.
We do not want one side behaving differently than the other, it is hard enough getting
it right if there are different sides. Another issues that has pros and cons to it, and let
us talk about that is an open rear wall. In this particular room it goes back another
15 feet this way. So we do not have any wall, this is couch, the seated position, so we
do not have any room boundary surfaces directly behind the listening position.
Now that’s a good thing, if you have speakers that are capable of filling this space. With
energy. It is a great thing for low frequencies because we have more volume for the pressure
to run to, so to speak. If you are after intimacy and development of your two channel system
in a real intimate kind of near field monitoring way, this will not work. Because it gives
you a lot of openness and a lot of spaciousness, and probably not the best format for more
critical listening environment, but if you want a big sound stage, openness and lots
of bass energy, a perfect scenario right there, in review let us make sure our side walls
are equidistant from our speakers and please no glass. We must make most surfaces hopefully
out of the same materials and the same density, and no pockets or closets, and depending on
the kind of listening we are gonna do, we may or may not need a rear wall. Thank you.