Very
few of us have the luxury of a dedicated room in which to put our
speakers. In most cases, we are squeezing them into a space that is too
small or have to deal with a living or family room that is not
symmetrical. Then there is the spousal factor, which may keep you from
putting the speakers where they need to be. In this column we will
start to look at how to overcome some of these real world problems.
This time we’ll look at how I dealt with a client’s room (let’s call
him Bob) without having to go there to measure it. For you, that
translates directly into a do it yourself project.
We’re starting off with a fairly easy one today, a room that has a
minimum of symmetrical problems. We’ll work our way into the big
problems in the columns to follow. Bob had a fairly ideal situation,
since he was moving into a new space. This meant that, while he already
had furniture, he was not totally locked into art or aesthetics. He was
also willing to make some furniture changes, but would be happier if he
could keep what he had. I felt that he had a workable arrangement and
that there would be a minimal sacrifice of sound quality with his
current furniture.
Bob sent me a floor plan of his empty room and one with the furniture
and speakers arranged to his liking. Take a close look at Figure 1
and tell me, “What’s wrong with this picture?” Instead of reinventing
the wheel, throughout this column I’m going to refer you to the RHT
archives and have you look at some of my past columns as a refresher
and space saver.
There are a few things that make
this room less than ideal, no matter how the speakers are arranged. In
the upper right corner is a door that leads to a deck. Depending on its
integrity, low frequencies could pass through this door. There also
must be enough space for the door to swing fully open. The right wall
is basically all glass. This can cause some serious first order
reflections and the outside view must be maintained. Bass loss through
the windows is also a possible issue. The kitchen is a very live
acoustic space and will generate undesirably long reverb times. The
kitchen island and closet are barriers that will affect the bass and
the stove/sink/refrigerator counter makes the room non-symmetrical. But
these are mostly problems that we have no control over, so let’s start
with how we can make the biggest difference.
The first problem is that the rug is green. This guy has no taste (just
kidding, I like green). But the rug’s position is a problem because
that’s where he put the speakers. He has a classic non-symmetrical
speaker placement. The right speaker is loading into a corner while the
left speaker hangs way out in space. The result is bad imaging and no
bass symmetry. If you look back at my first column, paragraph 10,
figures 3 & 4, you will see examples of why this is so, Click here.
Bob wanted good sound, but he also wanted a comfortable furniture
arrangement for entertaining friends. This is what led him to the
horseshoe layout of the couches and chair: practical but not
beneficial. Please notice the location of the comfy chair. This
location holds the possibility of absorbing a fair amount of bass from
the left speaker, depending on just how comfy the chair is. Also,
unless the tweeter and midrange drivers are above the height of the
chair, their coverage pattern will be affected by the chair’s proximity.
The couch on the right wall is sitting halfway in front of the right
speaker. This could have an effect on the bass, and like the comfy
chair, the mids and tweets. The love seat is in a good spot between the
two speakers, but rather close to the back wall.
And so we come to the coffee table. Coffee tables are the bane of my
existence. They sit low and directly in front of the listening
position. The big hard surface causes highly destructive first order
reflections. Bob’s table is large and while it is not that close to his
love seat, it still will get some reflections. Look at figure 2.
It shows the path length difference between the direct sound and the
coffee table reflection. Note the little comb filter icon at the lower
left. T his is what happens to your sound when the coffee table
reflection combines with the direct signal. Your brain cannot separate
out the reflection and you get poo-poo. For better understanding, figure 3 shows the frequency response of a room that has a coffee table in front of the listener (note the uneven response). Figure 4 shows the same room with no coffee table (note the smooth response). Need I say more? Lose the coffee table!
So how did I fix this whole situation? Well since I’m running out of
space and a picture is worth a thousand words (or in this case, 150)
take a look at figure 5.
In order to give the speakers symmetrical boundaries, I turned them to
face the kitchen. This solves some imaging and most bass response
problems, but not all of them. We still have the kitchen incongruities
working against us, but some things you have to live with. I used my
RPG Room Optimizer program to get me in the ballpark of where the
speakers work best in the room. For a refresher on RPG, see my second
column, paragraph 7 click here.
With my listening and speaker positions defined, I could now place the
furniture. In keeping with Bob’s entertainment desires, I maintained a
horseshoe-shaped seating environment. The comfy chair now becomes the
main listening position and the couch and love seat sit fairly
symmetrically in the room. Yes, they are a bit close to the speakers,
but the situation isn’t all that bad. They can actually help with
sidewall reflections. Speaking of sidewall reflections, I added a
tapestry on each wall to cut down on them considerably, once again
utilizing and maintaining symmetry. Note that the view is also
unobstructed for all. And on a final note, the coffee table is still in
use but out of the way.
If I were given the power, I would probably hang a curtain on a pull
rod in order to cut out some of the reflection energy coming from the
kitchen/entry. This could be pulled aside and kept out of the way just
right of the bookshelf, and then brought into the room, centered behind
the comfy chair for serious listening.
Next time we’ll continue to get into more problematic non-symmetrical
rooms. We’ll actually look at the problems I faced setting up my own
living room.
Bob
Hodas tunes many of the worlds finest recording studios and mastering
labs as well as many of the best private home theater and music
playback systems. His clients include: George Lucas, Abbey Road London,
Sony Music Tokyo, Paul Stubblebine Mastering and many more http://www.bobhodas.com/clients.html.
Based in Berkeley California, Hodas travels the world to tune audio
systems, designs acoustically excellent rooms and implements acoustical
treatments. Bob is available for consultation as well as in-home
tunings starting at $500. To contact Bob Hodas, email
This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
or call (510) 649-925
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Very
few of us have the luxury of a dedicated room in which to put our
speakers. In most cases, we are squeezing them into a space that is too
small or have to deal with a living or family room that is not
symmetrical. Then there is the spousal factor, which may keep you from
putting the speakers where they need to be. In this column we will
start to look at how to overcome some of these real world problems.
This time we’ll look at how I dealt with a client’s room (let’s call
him Bob) without having to go there to measure it. For you, that
translates directly into a do it yourself project.
