GIK Acoustics Presents
Acoustic Class Room
July , 2009 - Vol 6, Issue 6
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Greetings!
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Welcome to GIK Acoustics classroom!
From time to time we'll be sending out
newsletters to all of you to keep you up to date on a variety of room
acoustics topics. Our hope for this
newsletter is that it will help you get a
better understanding of how
acoustics work and how you can benefit by
treating your rooms. If you have any questions about the information in this (also ideas for topics to cover)
or any other issue, please feel free to contact us. The more YOU understand
the better YOUR listening environment will be. Also from time to time, we will interviewing a person in each newsletter, so if you'd like to show off your room to the
world or have something to say, please contact me at glenn.k@gikacoustics.com
Glenn Kuras
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What Is SBIR?
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SBIR (Speaker Boundary Interface
Response) - This is a term to describe
how the proximity of a speaker to a hard
boundary (wall/ceiling/floor) will change
the response, especially in the low end.
This is something that not a lot of people
understand nor consider when planning a
room.
Sound radiates from a driver in different
ways. Higher frequencies act like a ray
and move in straight lines from a point.
As you get lower in the spectrum, they begin
to radiate more like a sphere. By the time
you get below 500Hz or so, you're getting
pretty spherical radiation. By the time
you get to 125, it's purely spherical.
That said, imagine sound coming from a
driver at say 100 Hz that is coming directly
at you. There are other waves that are wrapping
around the cabinet and bouncing off the
front wall and then back at you. When 2
waves of the same frequency meet in this
way (one direct, one having bounced off
the front wall) there is an interface of
the 2 waves (some describe this as interference).
Constructive interference occurs when the
2 waves happen to be in phase with each
other. This yields a reinforcement of that
frequency or a peak in response. Destructive
interference occurs when the 2 waves are
180 degrees out of phase. This yields a
partial cancellation of that frequency (the
bounced wave has less amplitude) resulting
in a dip or null at that frequency.
This can cause WILD variations in frequency
response. However, one can sometimes use
this to your advantage. If you play with
speaker positioning in relation to the front
wall (behind the speakers) and the side
wall, you can 'tune' the response changes.
This can be beneficial when attempting to
smooth overall response.
Let's say that you have peak at your listening
position at a given frequency. If you can
find a place that images well and works
with the video positioning that will create
a slight dip due to SBIR, the net effect
is a smoother response at your seat. It's
kind of like using an EQ without having
to put one in your system.
Generally, you're best off if the distance
from speaker face to front wall, driver
centers to side wall, and driver center
to floor are 3 different dimensions in order
to not reinforce any specific set of harmonics
by having all the boundaries generate the
same SBIR effect.
If you still have issues, you can treat
the walls directly beside and/or behind
the speakers with appropriate materials
to further reduce the intensity of the reflected
wave to it's imact when interacting with
the direct wave is minimized. If you have
issues say from 125Hz up but OK below that,
then a thinner panel may be in order - say
2". If you have problems all the way
down, then something thicker may be appropriate.
Also remember that there will be interactions
between the sub and boundaries and also
between the sub and mains and their boundary
responses.
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On Air Mastering, Brooklyn, NY
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On Air mastering is a new mastering house located in Bushwick, Brooklyn,
catering to independent musicians and record labels that want the highest
quality mastering possible.
Featuring Legendary Audio's Masterpiece, conceived by Billy Stull
and designed by Rupert Neve, On Air has that unique sound that only 39 more
mastering houses in the world have, in a very simple, but effective setup, and
with the help of GIK's panels, On Air Mastering just sounds right!
On Air mastering has dozens of clients in the States and Colombia, South
America as varied as heavy rock, experimental jazz, folk, electronica, hip hop,
and pop. It's been very interesting to have artists over at the studio and hear
their comments on the mastering process, and see them leav  e very happy and
satisfied with a good product. Also of note is the fact that they commend the
look of the studio (since it's all red). The panels I got from GIK come in red
too, which was a plus. Installation was very easy, and as soon as I got them up,
one by one, I was hearing their effect on the acoustics. They make you focus on
what's really important, without making the room too dead. Clients also get a
new perspective on how much acoustic treatment and good monitoring affects what
they hear. I had Raj Patel, from Arup, an acoustic consultants firm, have a look
and measure the room and the results were very satisfactory! This is one aspect
of having a music-making room, be it recording, mixing, composing or mastering,
that you cannot skimp on money.
Here at On Air I help artists that do everything themselves achieve better
mixes, and create a relationship that is mutually beneficial: they learn how to
mix and I got better mixes so I can be creative with the mastering, instead of
trying to fix problems that can be prevented in the mix process. Another cool
thing that I really love to do is the spacing. I always try to do it with the
artist in the room, and we do it by feel, especially when you need a long space
between songs, those are my favorite.
Actually, the one thing I tell my clients is: acoustics, acoustics,
acoustics! Pictured with Tony Maimone Julian SilvaOn Air MasteringBrooklyn NYPhone: 347 523 3714Email: Info@onairmastering.comwww.onairmastering.com
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Bringing Your Sound to Life.
Sincerely,
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Glenn Kuras
GIK Acoustics
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