Perfect Speaker Boxes?
by Eddie Runner
We often hear talk (specially in car audio)
about certain boxes being RIGHT for certain woofers.
Many folks talk like a
given woofer wont even play at all if the box size is not exactly perfect!
What is perfect?
Manufacturers often recommend a certain box for their
Computer box programs can PICK the box size (or
tuning) that works best(?) with the woofer if you input the Thiele/Small
Is the box size the manufacturer recommends
How can it possibly be perfect when they don't even know what
kind of car your installing the box into?
We all know the car will change the
sound (this is called transfer function)!
How can they possibly choose the
perfect box size?
Many times the speaker manufacturers recommendation
is chosen not for perfect sound but for an average that might work well in the
Many times they might recommend the box that's easiest to build for
beginners or small (since many folks like woofs that work in small boxes)
or sealed instead of vented because it is less likely for you to blow your
speaker in a small sealed box than a large vented box! (if you blow your speaker
(a) they might have to replace it. (b) the company might get a reputation for
lousy speakers if they blow a lot) Sure, the manufacturers recommendation will
probably sound great!
But perfect??? Is the manufacturers recommended box
size really right for you?
Is the box size provided by computer programs
Again, how can it be unless they take into account the transfer
function of the car???
I don't know of a current popular program that
Most computer programs will calculate a box for you with the lowest
response and with the least ripple.
In car audio, this many times IS NOT the
Sometimes (specially in SPL competitions) the ripple the computer
program tries to avoid might actually be an SPL or bass boost!
Or for an
SQ car, a slight ripple (inaudible, an may likely be made up for by the cars
transfer function) might get you much deeper bass...
Is the computers recommendation
the perfect box?
Is the computer programs recommended box right for you?
How bout the difference in CUSTOM made boxes vs
Most real car audio enthusiasts would never consider
a PREFAB box, we all know the custom built boxes are far superior
BUT ARE THEY REALLY?
From my experience (installing since 1974) there is a
great amount of BADLY BUILT custom boxes being built!
Built so badly in fact
that for many cases a prefab box would be miles better!
A prefab box could be better than a badly built
custom box! And unfortunately there are many (maybe most of them) badly
built custom boxes. Installers that may not be good woodworkers, or good
woodworkers that don't know enough about acoustics.
I have heard some darned good systems with prefab boxes and
some very poor systems with custom built boxes..
important if your gonna pay high dollar for an installer to build you a custom
box that the installer be good at building boxes or you might just as well have
spent your money on a pre-fab and spent the left over money on something else.
PLUS, since we mentioned installers, how many
really have any background in speaker design?
Many claim to be experts, but in
the real world most installers just build the so called custom boxes with no
AUDIO PHYSICS in mind. So for a custom box, its important the installer be not
only a carpenter but also an expert at loudspeaker box design...
Or a pre-fab
box might be the better choice! ;-)
And, in reality, there is no PERFECT box, and to really
custom build a box to perform as good as possible in a given vehicle it requires
huge stacks of expensive test equipment, lots of woodworking tools and
saws, and building, testing then
rebuilding and retesting, and rebuilding and retesting again and again and again
until no more good is achieved.
This is done only by a few crazy competition
gurus or a few nutty hobbyists (we call em TWEEKS), certainly NOT for the average car audio guy, or
even the average installer, and most customers would NEVER want to pay for all
that time and materials to really seek perfection...
So, I think it would be safe to say most so called
perfect boxes are no where near perfect, they can all be improved on. And even
if they were perfect, putting them in a car will change them, even the direction
the box fires in the car can have an effect!
And it makes me laugh when I hear a fellow say
something like " the manufacturer recommends 1.5cu ft for this speaker, it
wont work in 1.25cu ft!"
Sure it will!
If that's all the space you have,
There are so many variables involved there is
a chance the NON-PERFECT box might even sound better than the so called perfect
Try it ;-)