An essential habit in audio recording is Critical Listening,
the professional practice of listening in a systematic and careful way to audio
in production in order to make it sound better for others, including producers
and end users.
In this column I want to discuss an interesting myth that has
rattled around the industry for years (I’ve certainly contributed to the
rattling): “The Myth of Crummy Speakers.”
For years, audio professionals have used Avantone Mixcubes to determine audio quality on small speakers.
That myth is based on the assumption that our end users all
or mostly listen on crummy speakers. Therefore, we reason, we need to do our
production work on crummy speakers as well, so that (a) we can hear all the
crumminess that our end-users are subjected to, and (b) we can try to “make our
audio sound good” on our crummy speakers in the hope that it will then also
sound good on their crummy speakers as well.
There is even a brand of speakers that
has been widely used as a reference for “crummy speakers”: the Auratone (and a
successor, the Avantone). These are small cubes with a single 5-inch driver and
a retail price of approximately $100/speaker. I have a pair standing by in my
studio (that I haven’t actually used since 2003!).
A LACK OF EXCELLENCE
The first thing to note, when we start to consider this, is
that not all crumminess sounds the same. In fact, crumminess is inherently
diverse, so that the crummier things are, the more different ways those
crumminesses manifest themselves. Crumminess is, in fact, a massive random
accumulation of errors in design, manufacture and usage.
Such crumminess is usually a function of some or all of the
following: inappropriate design goals, inadequate design specifications and
standards, inadequate budgets, and indifference to outcomes.
What this all means is that crummy
speakers are much less likely to sound alike than excellent speakers,
and we can rest assured that whatever crumminess we choose to use will probably
sound different, perhaps much different, than most of our end-users’ crummy speakers.
The problem this presents to us is that we cannot count on
our crumminess resembling the range of crumminesses that our listeners must
Thought about this way, it is actually fairly obvious.
THE IMPORTANCE OF SPEAKER TOPOLOGY
There is more to this, however. Loudspeakers are complex and
imperfect devices that utilize a small family of topologies based on the number
of drivers included in the design.
At the same time, the number of drivers determines something
fundamental about the bandwidth (or frequency spectrum) of the loudspeaker,
which in turn determines much about “how it sounds.”
So a single-driver speaker, such as the Auratone, can only
have a quite limited bandwidth. The 5-inch driver of the Auratone is too small
to generate long wavelengths (low frequencies) and too large to generate very
short wavelengths (high frequencies). As a result, it has easily observed
And here’s where that myth has some validity. The Auratone
will, in many respects, resemble all similar
single-driver loudspeakers of approximately the same size (say, from 4 inch to
7 inch). Such speakers show up in very cheap cars and trucks, as well as many
cheaper boom-boxes, table radios, cheap TVs and the like.
By the same token, a two-way speaker, with a tweeter and a
woofer mounted in a small box (a so-called “bookshelf” speaker, typically),
will have much in common with most of its topographical siblings. The tweeter
will usually be designed to cover the top three octaves (say, 2.5 kHz to 20
kHz, sort of), and will be crossed over to a woofer designed to cover perhaps 4
octaves (which is really a stretch) from, say, 125 Hz to 2 kHz.
There will often be an audible dip in response between the
woofer and the tweeter, and the lower bass will also be comparatively weak.
Such behavior will be characteristic of most such small two-way “bookshelf”
WHAT I’VE FOUND
Over the years that I’ve struggled with
this, I’ve tried a lot of things. My neighbor, mentor and ultra-engineer, Tom Bates,
makes the case that “you can’t quit mixing until your mix sounds good on all of
the available speakers, not just some of them.” So I’ve tried going through an
exhaustive auditioning process, including listening to my production work (both
mixing and mastering) on multiple speaker systems in the studio, on a boom box
in the kitchen, a home theatre system in the living room (complete with Dolby
Pro Logic) and several car systems (where I audition while parked, driving
around fast, driving around slow, top up, top down, etc.).
I’ve also asked some other mix and
mastering engineers what they do.
Little by little, especially after the
quality of my monitors improved because of a Bang & Olufsen project I’ve
been involved with, I’ve been able to set this obsessive range of testing
aside. I’ve done this both because it can be exhausting (and expensive for the
client!) and because as I got more and more grooved into my monitors, I found I
had fewer and fewer surprises when I checked my work on other systems. I came
to “know,” beforehand, what, for instance, the system in car #2, at speed, with
the top down, was going to sound like.
WHAT DOES IT ALL MEAN?
My advice to you is this: Do your
critical listening and production work on the best speakers you can obtain.
Then check your work on speakers of various appropriate topologies (i.e.
boomboxes, TVs and bookshelf speakers) of the best quality you can obtain. That
should enable you to get a reasonably clear idea of “what it will sound like”
for those topologies, in an idealized sort of way, with as few extra errors as
possible. Your speakers may not sound as crummy as your end users’ speakers do,
but you’ll be able to guess more accurately at the general range of crumminess
that they are encountering.
Some years ago, I took part in a
loudspeaker evaluation project that directly addressed these issues. You can
read about that adventure on my website www.moultonlabs.com. It’s
actually fairly interesting, if you’re curious about these things.
Dave Moulton is an audio engineer and producer,
author, composer, educator and acoustician. He operates Moulton
Laboratories/Digital Media Services in Groton, Mass. This article was first
published in TV Technology magazine.