How I Tuned My Own (Difficult) Room – Without Blocking The View of The Golden Gate Bridge
Sunday, 01 June 2003
AV Education on RHT
How I Tuned My Own (Difficult) Room – Without Blocking The View of The Golden Gate Bridge By Bob Hodas
Last
time we looked at a room that needed help but was not a big challenge.
So as promised, now we get to look at my mess. I’ve been in this house
for about 13 years and the system has evolved from large stereo
speakers to small, stand mounted stereo speakers, to a 5.1 setup with
five Meyer Sound Labs HD-1s and two Revel B-15s for the LFE channel.
While I like to watch movies, my primary focus is music. So for me, the
speaker placement took precedent over everything else. It was important
to have a setup that conformed to the same standards by which I tune
studios. At the same time, when my girlfriend moved in, I had to figure
out a way to make some compromises without sacrificing the sound to any
degree.
Let’s look at the floor plan for my room (Figure 1).
I have a living room that has open doorways next to the left front and
left surround speakers. There is a small window on the right wall
towards the front. A brick fireplace sticks out into the rear of the
room. My ceiling slopes up from the front picture window side (8’11”)
toward the fireplace (10’4”) at about seven degrees. All of the front
speaks back up to the large picture window. I also have a center
speaker that sits at the same height as my left/right speakers.
Regrettably the center speaker sits right in the middle of the living
room picture window and blocks the view (Golden Gate Bridge). That
doesn’t float well with my girlfriend but luckily at my house, it’s
“love me, love my speakers”. I know that is not a workable attitude in
the real world and we’ll look at how I overcame my problems (room and
girlfriend) below.
I chose to set the front speakers up on the picture window side for
various intuitive reasons which ended up being confirmed by
measurements. A) If I wanted to take advantage of the sloping ceiling,
the window wall made sense. Seven degrees is a good angle to send the
first order ceiling reflections into the back of the room. Setting up
on the fireplace side (my girlfriend’s choice) meant that the ceiling
reflections would be directed at the listener. You always want the wall
or ceiling angle to pass signal away from you, i.e. narrow in the
front, wide in the back. B) The window wall also had a possibility of
allowing some of the speakers rear firing low frequency energy to pass
out of the house, thus eliminating loading, and out of phase reflective
energy. My speakers were designed to be flat in free space, so I took
this into account. C) Both the window and fireplace walls have the same
disadvantage in that there is only one full corner due to the walkways,
which results in non symmetrical bass response. D) The right side wall
had an advantage since it has two full corners. But I was a bit
concerned about the fireplace sticking out 30 inches, which could
create bass problems for the right front speaker. Setting up on the
right side wall also meant that the ceiling would be at different
heights for all of the speakers, not very symmetrical. And then there
was the simple fact that, esthetically, the furniture setup would have
been just plain weird (ignoring both the view and the fireplace). D)
For future consideration, speakers on the window wall gave me the
longest throw and more ceiling height if I ever mount a projector on
the ceiling in the back.
The above reasoning for placement was then double checked by analysis.
Remember that I’m a room tuner and have the advantage of good
measurement gear, which allows me to fine tune the speaker placements.
Without bursting your bubble, getting the speakers in the proper spot
in a room like this would be quite difficult and time consuming to do
by ear.
I started with the window wall since I felt that was going to give me
the best results. I actually ended up finding a couple of fairly decent
spots for the left and right speakers (fig. 2). My methodology was the same as I described in Sound Tips 1 (see “How To” archives),
experimenting with speaker and listener positions until I could close
in on a solution. It’s quite a bit easier using an analyzer though.
When you move the speaker or listening position on an axis, you get
immediate feedback on what frequencies are affected and whether or not
you are heading in the right direction.
Remember my
girlfriend’s desire to have the speakers on the fireplace wall? I
decided to measure that wall next for a couple of reasons. 1) It would
make her happy. 2) It meant that mounting my 50” plasma above the
fireplace would be real cheap and simple. 3) Esthetically, it works for
the room. 4) I knew that I could easily treat the ceiling for the first
order reflection problems. Well, much to our disappointment, the bass
response totally sucked (and was sucked out) on that wall. I just could
not find a good speaker/listener combination that gave me even an
acceptable frequency response. Why? Remember that this acoustic stuff
is only part science and that there is an element of voodoo. But
basically, the dimensions just worked against us. The differences
between the window and fireplace walls are ceiling height and the
fireplace itself, so my intuition turned out to be correct.
The above measurements also spelled doom for the right side wall since
the ceiling height and fireplace had the same effect on the right front
speaker for that layout.
If I were to give this a go without measurements, my best guess would
be to try the following. Utilizing the RPG Room Optimizer program, I
would first find the front right speaker position since it has a real
corner behind it. I would restrict the listening position in the Y-axis
(width) to keep the listener centered in between the right and left
living room walls. I would use the distance between the far kitchen
wall and right wall as the Y-axis dimension since both speakers will
travel that path and the opening to the kitchen is fairly wide. That
ignores the tangential reflections for the left speaker, but hey, I
said I’m guessing here. I’m also throwing out the fact that the ceiling
has a seven degree slant, but I figure that the bass wavelengths are
long enough that it won’t have a huge effect. I would use the ceiling
height above the speaker for the Z-axis. So essentially I asked the
program to give me a non-symmetrical set up. I decided to run it and
see what happens (fig. 3).
Amazingly enough, RPG was able to deal with a listener position that
did not appear to be symmetrical. For some reason, it didn’t like my
idea of using the right speaker as the primary so I switched to the
left. When I ran the numbers, the program spit out a position that
matched my existing listener and speaker distance from the front wall.
The predicted speaker width was wider than my setup but I have the
restriction of a table in the front right corner, so that was my
self-imposed limitation when I set up the room. Pretty cool, actually.
Some day I’ll take out that table and try the wider stance (busman’s
holiday).
Well, I’m only halfway into this and I’ve totally exceeded my space.
See, non-symmetrical rooms are really difficult. No easy fixes. So we
will finish this up in the next column.
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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Last
time we looked at a room that needed help but was not a big challenge.
So as promised, now we get to look at my mess. I’ve been in this house
for about 13 years and the system has evolved from large stereo
speakers to small, stand mounted stereo speakers, to a 5.1 setup with
five Meyer Sound Labs HD-1s and two Revel B-15s for the LFE channel.
While I like to watch movies, my primary focus is music. So for me, the
speaker placement took precedent over everything else. It was important
to have a setup that conformed to the same standards by which I tune
studios. At the same time, when my girlfriend moved in, I had to figure
out a way to make some compromises without sacrificing the sound to any
degree.
Let’s look at the floor plan for my room (Figure 1).
I have a living room that has open doorways next to the left front and
left surround speakers. There is a small window on the right wall
towards the front. A brick fireplace sticks out into the rear of the
room. My ceiling slopes up from the front picture window side (8’11”)
toward the fireplace (10’4”) at about seven degrees. All of the front
speaks back up to the large picture window. I also have a center
speaker that sits at the same height as my left/right speakers.
Regrettably the center speaker sits right in the middle of the living
room picture window and blocks the view (Golden Gate Bridge). That
doesn’t float well with my girlfriend but luckily at my house, it’s
“love me, love my speakers”. I know that is not a workable attitude in
the real world and we’ll look at how I overcame my problems (room and
girlfriend) below.
