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WAVE
TECHNOLOGY
MaxxBass® and The Missing Fundamentals of Bass
T E X T
u
P A T
NE of our goals at Car Audio and Electronics is to
introduce new technologies that we think will have an
impact on the industry and ultimately everyone who enjoys
car audio systems. MaxxBass® is so new you can’t go out and
buy it for your car yet; however it’s exciting enough that we
wanted to give you a glimpse of what it can do. There are currently several companies developing products with MaxxBass.
As they get closer to introduction we will give you a heads up
on who has it and where to find it.
A Brief History of Bass
Humans have been in love with bass
since they learned to make music by striking sticks on animal skins stretched across
hollow logs. Bass, from the boom of an
ancient bass drum to an electric bass guitar,
has always captivated us in a way that still
seems hard to define.
Our love of bass has driven an on-going
search for ways of creating more and better
low frequency sounds. Virtually every
instrument created since the beginning of
time has had a low bass producing example.
Drums, horns, woodwinds, stringed instruments — all have a version that is intended
to play predominately bass frequencies. The
goal each of these instruments has always
been “louder” and “lower” bass. This search
came to a peak in early middle ages when
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the first pipe organs were created and
installed in cathedrals. Going to church in
the Middle Ages was pretty much the social
high point in everyone’s lives. It of course
filled the spiritual needs, but it also was an
opportunity to see and hear things that you
couldn’t get anywhere else. It was in many
ways, equal part spirituality and entertainment. The pipe organs that were installed in
the larger cathedrals offered a whole new
level of experience for the bass fanatics of
that period. For the first time they were able
to hear and, more importantly, feel low bass
that was at the very limits of their sensory
capabilities. The bigger churches and cathedrals could seriously rock their congregations. They had huge pipes that could produce “pedal tones” or really really low notes
at levels that shook bodies much like car
T U R N M I R E
audio systems do today. From the churches’
standpoint, all this bass was just what they
wanted. It drew big crowds and moved the
congregation in the same primal way that
drums and other loud bass instruments
have done since the very beginning. As
more and more churches added these huge
pipe organs into their designs, people came
to expect this physical experience of music
to be a part of their worship.
The problem was that only the biggest
churches could house the pipes necessary
to achieve the really low pedal tones. Some
of these pipes were 40 feet long and a full
set would take up a large area. In fact the
problem with getting bass in small churches is very much like the one we face in our
modern car audio systems. The key issue in
both cases is how to fit big transducers in
small spaces.
The Missing Fundamental
In the early 1700’s some composers of
written music, specifically for pipe organ,
found that they could “trick” the listener
into hearing low bass tones that weren’t
really there if they played a certain combination of notes that were higher than the
low tone or “fundamental” that they wanted
to be heard. For example, if they wanted the
listener to hear a low C then they could play
a C an octave higher and a G above that, and
the low C would magically appear in the lis-
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tener’s head. This phenomenon revolutionized the way organs were designed over the
next 200 years. Instead of building massive
pipes to create the low pedal tones, designers could make different notes sound when
the low note was hit on the keyboard; and
the low note would magically appear as if it
were played on the big pipes. While this
effect wasn’t perfect — these phantom low
bass notes didn’t exactly shake the room —
they did make the music writing for the
largest pipe organs still sound good in
smaller churches.
The actual mechanics of the “Missing
Fundamental” have been investigated by
such notables as Helmholtz (the guy who
figured out how tuned tubes or vents work),
and has been the subject of many studies
tricking your ear into hearing bass that isn’t
really there.
One of the first applications for this
technology was an effect Waves called
MaxxBass that is applied in the recording
studio on computer work stations. It gave
bass drum tracks more kick with less
speaker excursion and made bass tracks
sound more “punchy” and dynamic. This
was first used in 1999 and has now become
a standard tool used on many of the top
CD’s made in the last few years. If you have
listened to “Lady Marmalade”, by Christina
Aguilera (if you haven’t, you must have
been in a coma), then you have heard
MaxxBass used as an effect.
Waves knew that the their technology
was more then just an effect to be used in
the world of recording studios.
In fact they believed that it
could be incorporated into consumer products, changing the
way the world of audio designed
products that make bass. The
key to making this happen was
to offer an inexpensive real time
solution for MaxxBass that did
not require a computer audio
workstation. In late 2001, and
after three years of development, Waves completed the
MX3000AS MaxxBass ASIC (Application
Specific Integrated Circuit), an inexpensive,
tiny surface mount IC that incorporates all
of the power of MaxxBass to harness the
Missing Fundamental phenomenon.
“In fact the problem with getting bass in small churches is
very much like the one we
face in our modern car audio
systems. The key issue in both
cases are how to fit big
transducers in small spaces.”
that tried to define how we hear musical
notes. The most current theory suggests
that our ears really don’t hear single pure
notes directly, but rather hear them as the
combinations of their harmonic content.
This suggests that it is possible to completely convince our ears that we are hearing a
pitch that is not really there, if they are
given the right combination of harmonics.
In fact, if this is true then it should be possible to do the same thing in our car audio
systems that organ designers were doing for
small churches: get more bass from smaller
transducers, or speakers.
MaxxBass
In 1995, Meir Shashoua, the CTO of
Waves’ (the leading company producing
computer-based audio signal processing for
professional applications) developed the
theory describing the exact combinations of
harmonics required to produce the missing
fundamental effect. This technology was
patented in 1999 (5,930,373) as a method
for creating a “psuedo low frequency psycho-acoustic sensation” — in other words,
What MaxxBass is Going to do
for Car Audio
MaxxBass changes all of the rules that we
have learned about making bass in our car
systems. It lets a 4 x 6 door speaker which
usually can only play down to 80 or 90 Hz
sound like it is playing all the way down to
40 Hz. In fact it makes us hear all of this
bass while the speaker is actually moving
less. This is because all of the frequencies
below the point where the MaxxBass effect
starts (called the Fc) are actually rolled off
with a crossover built into the chip. So the
bottom line is you get more bass and less
speaker excursion. This means your speakers play louder and lower!
The MaxxBass effect can be used on systems of any size. Factory systems with a
small external amp will sound like you
added a small subwoofer. Upgraded door
Car Audio and Electronics June 2002
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How MaxxBass works
The graphics below show a typical application of MaxxBass for car audio. The speakers are commercial 6"
coaxes with an F3 of 80 Hz. This means that for all practical purposes they really don't play much lower then
an octave above low E on a bass guitar (41.2 Hz.) The speaker in this example has an Xmax of 8mm which
makes it at the higher end side of speakers of this type.
If we play some music where there is a strong single note of bass at 40 Hz. you can see that there is a single
line of energy at 40 Hz. and the speakers excursion is right at its excursion limit. Because of the speakers
relatively small size it is unable to move much air at 40 Hz. and you are barely able to hear this note as part of
the music.
40 Hz. tone without MaxxBass effect
Maximum excursion
at 8mm
20 Hz.
Frequency
100
500
1KHz.
When we pass the same signal through a MaxxBass processor, you can see that the 40 Hz. signal is reduced
about 6 dB, and the harmonics related to this signal are created in the proper spectrum for your ear to hear
the 40 Hz. note. The speakers excursion is reduced by 4 times to 2mm which means the speaker will take 4
times more power before it hits its excursion limits. Now you actually hear the bass in the music as your ear is
tricked into creating the sound in your mind.
More bass, higher power handling and higher SPL's before distortion - Money for nothing and your bass for free.
40 Hz. tone with MaxxBass effect
2 mm or 1/4 the
excursion
20 Hz.
Frequency
100
500
1KHz.
“In fact, if this is true then it should be possible to
do the same thing in our car audio systems that
organ designers were doing for small churches: get
more bass from smaller transducers, or speakers.”
speakers with a multi-channel amp and
small subwoofer will sound like you added
an even bigger subwoofer.
MaxxBass gets even more exciting when
complete systems are designed around the
technology. When your speakers don’t need
to play really low, you can design them to be
much more efficient. In a paper presented to
the Audio Engineering Society (AES),
Martin Collums, a well respected acoustical
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engineer, calculated that a MaxxBass
designed speaker system with 5” speakers
would be 7.5 dB more efficient then the
equivalent standard design and ultimately
play 6 dB louder.
This new technology isn’t a replacement
for the chest-thumping low end that you get
from a row of 12” subs with a couple thousands watts of amps driving them. That
kind of bass is as much felt as it is heard.
MaxxBass®
Pro 101
■ BY ERIC HOLDAWAY
his is the part of this job that I LOVE! I
get to be one of the first people in the
industry to get my hands on one of the
hottest pieces of technology around in prototype form. But I’m getting ahead of myself.
Today, we are reviewing the MaxxBass
Technology from Waves. This is a sneak peak
at the future! Patrick has laid out the history
and functions above, so I will try to stay on
point with the sound of this device.
When Casey told me about another black
box that was going to change the way audio is
done, I gave him the obligatory “Uh-huh.” (At
some point Casey had to shake me awake as
he was telling me about it.) To say the least, I
was a little surprised when he actually showed
T
“And the more I
listened to the
MaxxBass, the more I
found myself decreasing
the Intensity level.”
up a month later with this box under his arm
and that little grin of his that tells me I’m
about to have a tasty course of my own words
to eat.
As I was saying, the tech editor shows up
with a prototype demonstration unit of the
MaxxBass processor from Waves. No, you
can not have one....yet. The demo unit is
designed to be installed into the low level RCA
leads between a head unit and the amplification. It has few adjustments, so that makes it
simple to set up and use. And, as I understand
it, the processor will be built into electronics
like amps and pre-amps, which will either have
pre-set parameters or minimal controls, just
as the demonstration unit does. This unit has
three knobs and a button. The knobs are “Input
Level,” “Intensity,” and “Frequency.” The button
is a simple bypass switch to turn the circuit on
and off.
To test this new device, I set up a pair of
the USD Audio D-62 WaveGuide separates,
that feature a pair of USD Audio 6.5”
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midrange/woofers, a pair of horn loaded compression driver tweeters called the
WaveGuides, and passive 2-way crossovers
for the front channels. For the rear channels,
I set up a pair of Alpine SPR-176a 6.5” separates. I powered the system with a Crossfire
VR-142 amplifier in stereo at 35 watts per
channel with the MaxxBass in the RCA line.
I decided to give the MaxxBass a wide
selection of recordings for the test. I listened
to rock, folk to rap, classical and jazz. Heck, I
even played the radio and used XM Satellite
service to see if I could trick the MaxxBass unit
into failing to achieve its stated objectives.
I started with the unit in the bypass position to get a mental setting for what the
speaker system sounds like not processed. I
put in 10,000 Maniac’s album “In My Tribe.”
Track 7 is “Peace Train,” a track that opens
with a strong 30Hz bass beat and a rhythm
guitar. With the MaxxBass defeated, the bass
tone hearable on the 6.5” speakers with which
I was testing.
Then I put in some rap, looking to see if I
could overload the unit and get some kind of
distortion or break-up from it. But I found that
I could play the speaker system at a higher volume level with the MaxxBass on.
Next came jazz. Sandy Liarag of Boston
Acoustic gave me a great CD that Boston had
produced called “Music for Bottom Feeders.” I
have never been able to find another copy. A
side note: It would be great if Boston would rerelease all of the CD’s that they produced in
the ‘90’s.
On the third track, “Music makes the
World Go Around” I started listening for any
artifacts that the MaxxBass may add or subtract from the playback. At 1:30 into this
song, there is a loud staccato piano note that
will jolt you. I went back and forth with the
MaxxBass unit in and out of the signal path to
hear if there was any degradation to the
sound, and I could hear none.
The graphics on the previous page show
a typical application of MaxxBass for car
audio. The speakers are commercial 6”
coaxes with an F3 of 80 Hz. This means that
for all practical purposes they really don’t
play much lower then an octave above low
E on a bass guitar (41.2 Hz.) The speaker in
line was “missing”. I restarted the track and
this example has an Xmax of 8mm which
turned it on and the bass line was clearly audimakes it at the higher end side of speakers
ble. Interesting, I thought. I spent the next
of this type.
couple of minutes fine tuning the MaxxBass,
If we play some music where there is a
which was quite easy to do.
strong single note of bass at 40 Hz you can
Restarting the track again I switched the
see that there is a single line of energy at 40
unit in and out a number of times as the track
Hz and the speaker is right at its excursion
progressed and, each time, I was rewarded by
limit. Because of the speaker’s relatively
a fullness of the subwoofer information being
small size it is unable to move much air at
added to the system, without the addition of a
40 Hz; and you are barely able to hear this
subwoofer. The effect of the unit was not that
note as part of the music.
of a loudness contour or an equalizer or even
When we pass the same signal through a
a BBE. It was very much like having a small
MaxxBass processor, you can see that the
subwoofer turned on and off. It was almost
40Hz signal is reduced about 6dB, and the
weird, in that I could hear the subwoofer inforharmonics related to this sigmation, but I did not get the pant-leg shaking
nal are created in the
effect of a subwoofer.
proper spectrum for your
And the more I listened
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ear to hear the 40Hz note.
to the MaxxBass, the more
The speaker’s excursion is reduced by four
I found myself decreasing the Intensity level.
times to 2mm which means the speaker will
Which is exactly what Patrick told me I would
take four times more power before it hits its
be doing once I got into the test. At 0:50 into
excursion limits. Now you actually hear the
“Piece Train” there is a drum kit, bass drum
bass in the music as your ear is tricked into
series of kicks. You can hear the mallet strikcreating the sound in you mind.
ing the skin and you can hear the skin noise,
More bass, high power handling and
but without the MaxxBass in the “on” position,
higher SPL’s before distortion — money for
the actual tone of the bass drum was gone.
nothing and your bass for free. v
The unit made the kick drums “fundamental”
At this point, I began to wonder if I was losing it. So I called my trusted sidekick Tuna in
for a listen (Tuna is my long suffering employee, Henry Sudit.) Now, to Tuna, if it don’t
bump, it ain’t worth having. I asked him to
have a seat and listen to the track and just
push this button on and off, then tell me what
he heard and what he thought.
Tuna listened for a bit, then pronounced
that the button turns on a subwoofer. When I
showed him the system was just 6.5” speakers — well, his exact quote I do not think we
can print, but it went something like this, “Holy
Bombastic Bass, Batman! That could not possibly be just 6.5” speakers!” You get the idea.
As I listened to more material the results
just kept coming back the same. The
MaxxBass does what Waves says it does. It
improves the bass response of small speakers in a real and dramatic fashion. And now I
have a number of applications in my mind for
sound-off cars that I am going to go out and
start testing right now, because the
MaxxBass guys are going to want this unit
back soon! I would too. It is impressive technology. I fear that MaxxBass will give its
largest benefits to the OEM guys. It could be
coming to a Ford or Chevy near you soon. v
However, if you don’t have the room for that
kind of system, a product with MaxxBass
will let you “hear” more bass.
Where Do I Get It?
As we said in the beginning, MaxxBass is
so new that you can’t go out to your local
car audio store and buy a product that uses
it. Currently, there are a handful of companies that are developing products with
MaxxBass built in. The products will come
in a wide variety of types and applications.
Multi-channel amps, preamp/processors,
and stand-alone MaxxBass processors are
some of the products on the drawing boards
now. Over the next year, you will begin to
see it in more and more aftermarket products including head units and ultimately in
OEM products. You can find out more about
the technology by visiting the Waves Web
site at www.maxxbass.com.
How It Works
MaxxBass® Pro 101
“I found that I could play the speaker system at a
higher volume level with the MaxxBass on…”
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