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GENESIS OF BURWEN BOBCAT
By Dick Burwen
When my amateur radio station W1NMG shut down due to World War II, I became interested in
Hi-FI audio. At that time it was an accomplishment to design a vacuum tube power amplifier
having extended frequency response from 30 to 15,000 cycles per second (now called Hertz).
In my first major hi-fi system in 1945, I realized the losses in speaker response at extreme low
and high frequencies required frequency response equalization (EQ) to extend the range. My
3-watt, 6L6G pentode power amplifier design used feedback to boost 30 Hz and 15 kHz for
brilliant highs and deep bass without boom. It had bass and treble controls too.
My successively better audio designs over many years used ever more elaborate, feedback
tone controls as a key element in improving the sound. I learned that the frequency response
of the entire system, including the recording, phono preamplifier, power amplifier, speakers,
and room is the number one factor in producing high quality sound.
Besides low distortion and the usual specifications for high fidelity equipment, two other most
important elements of fine sound are the acoustics of the recording environment and the
listening room. When sound is reflected from various walls and surfaces, differences in travel
times cause it to add to or subtract from the direct (original) sound at different frequencies,
producing big ripples in the frequency response. Contrary to many professional opinions that
ripples are bad, I found they are what make music sound really musical. So, I prefer live rooms
over dead rooms which are clearer, but too revealing of imperfections.
For more than 20 years I was privileged to record in what to me is the best hall in the world,
Jordan Hall at the New England Conservatory of Music, in Boston, Massachusetts. I recorded
the Boston Philharmonic Orchestra, the Civic Symphony Orchestra of Boston, and Boston
Baroque using two omni-directional microphones pointed at the ceiling. Omni-directional
microphones are actually quite directional at 20 kHz and the increased high frequency
reflections, together with a little EQ, made the recordings smoother and more musical.
I always loved the reverberation in recordings made in Jordan Hall, but I hated the artificial
reverberation I heard in many commercial recordings. Jordan Hall's reverberation makes the
sound brilliant, full, and musical. Artificial reverberation can turn instruments like cymbals into
mush. Newer sampling reverberation more closely resembles real halls, but I find it is not really
what the ear likes to hear.
My 20,000 watt hi-fi system has been in development since my home was designed and built
around its five walk-in speaker horns 43 years ago. Before acquiring modern computers, I used
three microphones to pick up the sound from the speakers and add a little of it into the input
signal. Due to the 22 milliseconds or so sound travel time from the speakers to the
microphones the additions and subtractions at different frequencies caused ripples in the
frequency response that made the sound pleasingly brilliant and very musical.
Although I was equipped for genuine 4-channel analog recording with a mix to 5 channels, I
discovered I actually preferred my 2-channel recordings processed to 5 channels. The
contributions from the front left and front right channels to the front center and rear speakers
produced a fuller, smoother, more pleasant, room-filling sound.
When fairly powerful digital signal processing (DSP) chips and circuit boards became available I
designed software that used four $7500 processing boards inside a Pentium 1 computer
together with two stereo external digital-to-analog converter (DAC) boxes. The software system
replaced the microphones and the tone controls for my front speakers. It generated simple, but
pleasing reverberation for my rear speakers. My analog equipment was able to mix a little of the
rear channel reverberation into the front channels for greater smoothness.
The completed reverberation software, in conjunction with my rear channel tone controls,
added subtle ambiance extending to frequencies as high as 20 kHz. For the first time, I got to
like artificial reverberation - my own. It didn't sound like reverberation. Not only that, it nicely
supplemented the reverberation already present in phonograph records and CDs.
I realized the improvement my new ambiance software made was just a taste. I wished I had 500
times the processing power to produce many more sound reflections. In 2002 this became
possible with Intel's development of the Pentium 4 processor, which I estimate is equal to 400 of
the Motorola DSP96002 chips used on my old DSP boards.
In the fall of 2002, when I retired from circuit design consulting, I embarked on improving my hi-fi
system, and maybe producing a commercial product to share with others, via new software.
After five years of intense work, averaging more than 60 hours per week, I now have AUDIO
SPLENDOR and its derivative BURWEN BOBCAT. What took so long was writing 1,400,000
equations, some, more than 150 characters long, and making them all work.
Besides improving my sound with new tone controls and ambiance generation in 5 channels a
principal objective was to make my sound system easier and quicker to operate. With the
availability of 5-channel SACDs and movies, switching back and forth to 2-channel CDs and
optimizing my system had been a complex task. By the time I finished the setup my audience
became bored and often I made a mistake. Now, after saving my settings from a rehearsal,
clicking on a track in the Windows Media Player causes AUDIO SPLENDOR to set up my whole
system by setting 298 on-screen sliders and selecting among 364 buttons. Settings saved for
each musical selection in the TONE library automatically recall from 6 libraries: tone control
settings, reverberation characteristics, the mix, reverberation mix, source compensation, and
speaker or headphone compensation. Rehearsing is easy, as most recordings require setting
only 12 controls, affecting all 5 channels. The software also works in 2, 5.1 and 7.1 channels.
Part way through the development of this comprehensive software, I recorded test CDs one of
which I mailed to my long-time friend Mark Levinson. For many years prior, Mark had been
telling me how bad and fatiguing CDs and other digital recordings were and why he liked
old-fashioned analog recording. "Dick, solve this problem! If we can't improve CDs I will get out
of audio." As I had always used my ever-improving tone controls to rebalance the sound, so
almost every CD sounded decent to me, I was not convinced there was such a problem.
Upon listening to the test recording and others, Mark reported I had indeed solved the problem
of listening fatigue. My new ambiance generation, which had its greatest effect at extreme high
frequencies, really smoothed the sound, got rid of irritants, and made transients clearer, all
without losing high frequency resolution. I didn't even know I was working on the problem!
Mark was so enthusiastic that he urged me to make a simplified version of AUDIO SPLENDOR
without controls, available and affordable for everyone. We will call it BURWEN BOBCAT -
BURWEN OPERATING SYSTEM, BEST COMPUTER AUDIO TECHNOLOGY. It was all Mark's idea!
Around that time iPods and MP3s were becoming popular. Audiophile magazine writers often
derided the quality of MP3s as unlistenable on a good hi-fi system. Back to phonograph
records! Tests we and others made listening to BURWEN BOBCAT processed MP3s showed the
processed MP3s were actually preferable to the original CDs, even SACDs and LPs. Additionally
BURWEN BOBCAT processing reduced the audible difference between processed MP3s and
processed CDs from which the MP3s were made.
BURWEN BOBCAT RE plugs into the Windows Media Player (WMP) and for listening it processes
the signal on the way to your computer's sound card or DAC. It processes at 44.1, 48 kHz, 88.2
kHz, or 96 kHz, whatever WMP plays - CDs, WMA compressed or lossless, and MP3s. I save my
CDS on an external USB drive in WMA lossless format. When I make MP3s for my iPod there is
only one compression degradation, not two. If I want to, I can apply BURWEN BOBCAT
processing when ripping or burning CDs. It has an efficient file converter too, that can make
128 kbps processed MP3s or lossles WMAs at high speed from hundreds of WMA files in a
folder.
DACs in computers vary in quality from good to lousy. Even computers that sport 24-bit 192 kHz
DACs may produce good or bad sound depending upon how much ground noise the DAC picks
up from the noisy computing environment. So, you don't know what sound quality you are
buying in a computer until it is too late. To assure the highest quality sound reproduction, Mark
Levinson has made available on his Daniel Hertz Advanced Audio Designs, Inc. website an
external USB (Universal Serial Bus) connected DAC with the BURWEN BOBCAT name on its front
panel. He also has available a very high quality dual 50-watt power amplifier with a USB input,
called GENIUS.
BURWEN BOBCAT RE incorporates all the slider and button settings of AUDIO SPLENDOR, but I
have set them for you, giving you a simple choice of 19 processing selections on click-buttons
for 2-channel stereo. When you listen to BURWEN BOBCAT processed audio you don't hear it
adding what sounds like room reverberation or echo. The reverberation you notice is almost
entirely that already present in the recording itself. BURWEN BOBCAT adds what I describe as
ambiance without echo. It includes a lot of what audiophiles call "air". Rough sounding
recordings become smoother and more musical because the extreme high frequency
reverberation averages out the grit. Unlike natural reverberation, which tends to obscure
transient sounds, BURWEN BOBCAT stretches transients in time so they are more easily
perceived and become clearer. After getting used to this type of processing many listeners find
their original CDs played loud are quite irritating.
Real room reverberation and ordinary electronic reverberation have their greatest effect at
middle and low frequencies. When I first discovered the benefit of my high frequency
reverberation, I tried boosting the high frequency content of various sampled reverberation
programs to obtain a similar effect. That did not work at all. No resemblance.
To produce the brilliance and clarity of BURWEN BOBCAT's high frequency reflections in the real
world, imagine a saxophone player has a wall-size reflector with a hole through which the neck
of his instrument protrudes and the reflector is only 1/4 inch from the top open valve. The
reflector is in a different position for each different note. Physical dimensions make such high
frequency reflections impossible. They have to be produced electronically. You can't get this
effect at a live concert. Yet I find quick, high frequency reflections are what your ear really likes
to hear for clear, musical sound. Even at Jordan Hall, I sometimes think the sound ought to be
processed with my new high frequency reverberation technique.
In addition to its high frequency ambiance BURWEN BOBCAT incorporates a bit of tonal
rebalancing (EQ). The four different basic selections are designed to change the overall sound
very little while making it smoother and more musical, so they are suited to all kinds of program
material. Vocal, jazz, pop, classical, and movie modify the sound more and are better suited to
fixing certain problems in recordings. Once you get used to listening to the smoother high
frequencies, unprocessed recordings become irritating to listen to. Mastering engineers tend
to use the basic selections because they don't want to tinker with the intent of the original
recording.
When I listen to my own CDs I don't mind changing the sound completely. Frankly, among the
3000 or so CDs in my collection there are very few I care to hear sounding anything like the
unprocessed recording. One reason, I am told, is many older recordings were equalized via
monitor speakers that attenuated the 3500 Hz region where voices become shrill. These
recordings now sound screechy when played through more accurate speakers.
I use AUDIO SPLENDOR to augment extreme low frequencies, attenuate piercing high
frequencies, sweeten violins, widen the acoustic image, and fill the room with spacious
ambiance via 5 speaker systems. An important lesson I learned is you need to preserve the
high harmonics of musical instruments, but a little too much makes the sound unmusical. For
poorer quality CDs and TV audio I often use what I call EXTREME processing which almost
completely substitutes artificial reverberation for the main signal at high frequencies. My latest
development at this writing is BURWEN BOBCAT MONITOR which incorporates this sound in 5.1
and 7.1 channels.
Extreme processing also includes a feature I call NO SCREECH. It attenuates the 3500 Hz region
only during a singer's loudest high notes. BURWEN BOBCAT RE vocal settings have a dip in
frequency response in the same region and make a big improvement. However, fixed
attenuation can be carried only so far before the orchestra and a singer's quieter refrains
become muffled. With No Screech in BURWEN BOBCAT EXTREME everything is clear and
screech is gone.
BURWEN BOBCAT MONITOR is my full AUDIO SPLENDOR software without the controls and is
designed to work with a MOTU 828MK3 8-channel A/D-DAC. It produces its multichannel output
from a 1 to 8 channel analog input signal or the Windows Media Player where it is a plug-in. It is
also a DirectX plug-in for professional audio editors. Audio is processed at 88.2 kHz and you can
record and play 32-bit BURWEN BOBCAT multichannel files at 88.2 kHz. You can convert a folder
full of stereo files to 88.2 kHz multichannel. In addition it includes BURWEN BOBCAT RE with all
its listening, recording, and file conversion features. For studio monitoring or broadcasting
BURWEN BOBCAT MONITOR can apply any of 7 different processings to 1, 2, or 3 stereo analog
inputs.
By Dick Burwen
When my amateur radio station W1NMG shut down due to World War II, I became interested in
Hi-FI audio. At that time it was an accomplishment to design a vacuum tube power amplifier
having extended frequency response from 30 to 15,000 cycles per second (now called Hertz).
In my first major hi-fi system in 1945, I realized the losses in speaker response at extreme low
and high frequencies required frequency response equalization (EQ) to extend the range. My
3-watt, 6L6G pentode power amplifier design used feedback to boost 30 Hz and 15 kHz for
brilliant highs and deep bass without boom. It had bass and treble controls too.
My successively better audio designs over many years used ever more elaborate, feedback
tone controls as a key element in improving the sound. I learned that the frequency response
of the entire system, including the recording, phono preamplifier, power amplifier, speakers,
and room is the number one factor in producing high quality sound.
Besides low distortion and the usual specifications for high fidelity equipment, two other most
important elements of fine sound are the acoustics of the recording environment and the
listening room. When sound is reflected from various walls and surfaces, differences in travel
times cause it to add to or subtract from the direct (original) sound at different frequencies,
producing big ripples in the frequency response. Contrary to many professional opinions that
ripples are bad, I found they are what make music sound really musical. So, I prefer live rooms
over dead rooms which are clearer, but too revealing of imperfections.
For more than 20 years I was privileged to record in what to me is the best hall in the world,
Jordan Hall at the New England Conservatory of Music, in Boston, Massachusetts. I recorded
the Boston Philharmonic Orchestra, the Civic Symphony Orchestra of Boston, and Boston
Baroque using two omni-directional microphones pointed at the ceiling. Omni-directional
microphones are actually quite directional at 20 kHz and the increased high frequency
reflections, together with a little EQ, made the recordings smoother and more musical.
I always loved the reverberation in recordings made in Jordan Hall, but I hated the artificial
reverberation I heard in many commercial recordings. Jordan Hall's reverberation makes the
sound brilliant, full, and musical. Artificial reverberation can turn instruments like cymbals into
mush. Newer sampling reverberation more closely resembles real halls, but I find it is not really
what the ear likes to hear.
My 20,000 watt hi-fi system has been in development since my home was designed and built
around its five walk-in speaker horns 43 years ago. Before acquiring modern computers, I used
three microphones to pick up the sound from the speakers and add a little of it into the input
signal. Due to the 22 milliseconds or so sound travel time from the speakers to the
microphones the additions and subtractions at different frequencies caused ripples in the
frequency response that made the sound pleasingly brilliant and very musical.
Although I was equipped for genuine 4-channel analog recording with a mix to 5 channels, I
discovered I actually preferred my 2-channel recordings processed to 5 channels. The
contributions from the front left and front right channels to the front center and rear speakers
produced a fuller, smoother, more pleasant, room-filling sound.
When fairly powerful digital signal processing (DSP) chips and circuit boards became available I
designed software that used four $7500 processing boards inside a Pentium 1 computer
together with two stereo external digital-to-analog converter (DAC) boxes. The software system
replaced the microphones and the tone controls for my front speakers. It generated simple, but
pleasing reverberation for my rear speakers. My analog equipment was able to mix a little of the
rear channel reverberation into the front channels for greater smoothness.
The completed reverberation software, in conjunction with my rear channel tone controls,
added subtle ambiance extending to frequencies as high as 20 kHz. For the first time, I got to
like artificial reverberation - my own. It didn't sound like reverberation. Not only that, it nicely
supplemented the reverberation already present in phonograph records and CDs.
I realized the improvement my new ambiance software made was just a taste. I wished I had 500
times the processing power to produce many more sound reflections. In 2002 this became
possible with Intel's development of the Pentium 4 processor, which I estimate is equal to 400 of
the Motorola DSP96002 chips used on my old DSP boards.
In the fall of 2002, when I retired from circuit design consulting, I embarked on improving my hi-fi
system, and maybe producing a commercial product to share with others, via new software.
After five years of intense work, averaging more than 60 hours per week, I now have AUDIO
SPLENDOR and its derivative BURWEN BOBCAT. What took so long was writing 1,400,000
equations, some, more than 150 characters long, and making them all work.
Besides improving my sound with new tone controls and ambiance generation in 5 channels a
principal objective was to make my sound system easier and quicker to operate. With the
availability of 5-channel SACDs and movies, switching back and forth to 2-channel CDs and
optimizing my system had been a complex task. By the time I finished the setup my audience
became bored and often I made a mistake. Now, after saving my settings from a rehearsal,
clicking on a track in the Windows Media Player causes AUDIO SPLENDOR to set up my whole
system by setting 298 on-screen sliders and selecting among 364 buttons. Settings saved for
each musical selection in the TONE library automatically recall from 6 libraries: tone control
settings, reverberation characteristics, the mix, reverberation mix, source compensation, and
speaker or headphone compensation. Rehearsing is easy, as most recordings require setting
only 12 controls, affecting all 5 channels. The software also works in 2, 5.1 and 7.1 channels.
Part way through the development of this comprehensive software, I recorded test CDs one of
which I mailed to my long-time friend Mark Levinson. For many years prior, Mark had been
telling me how bad and fatiguing CDs and other digital recordings were and why he liked
old-fashioned analog recording. "Dick, solve this problem! If we can't improve CDs I will get out
of audio." As I had always used my ever-improving tone controls to rebalance the sound, so
almost every CD sounded decent to me, I was not convinced there was such a problem.
Upon listening to the test recording and others, Mark reported I had indeed solved the problem
of listening fatigue. My new ambiance generation, which had its greatest effect at extreme high
frequencies, really smoothed the sound, got rid of irritants, and made transients clearer, all
without losing high frequency resolution. I didn't even know I was working on the problem!
Mark was so enthusiastic that he urged me to make a simplified version of AUDIO SPLENDOR
without controls, available and affordable for everyone. We will call it BURWEN BOBCAT -
BURWEN OPERATING SYSTEM, BEST COMPUTER AUDIO TECHNOLOGY. It was all Mark's idea!
Around that time iPods and MP3s were becoming popular. Audiophile magazine writers often
derided the quality of MP3s as unlistenable on a good hi-fi system. Back to phonograph
records! Tests we and others made listening to BURWEN BOBCAT processed MP3s showed the
processed MP3s were actually preferable to the original CDs, even SACDs and LPs. Additionally
BURWEN BOBCAT processing reduced the audible difference between processed MP3s and
processed CDs from which the MP3s were made.
BURWEN BOBCAT RE plugs into the Windows Media Player (WMP) and for listening it processes
the signal on the way to your computer's sound card or DAC. It processes at 44.1, 48 kHz, 88.2
kHz, or 96 kHz, whatever WMP plays - CDs, WMA compressed or lossless, and MP3s. I save my
CDS on an external USB drive in WMA lossless format. When I make MP3s for my iPod there is
only one compression degradation, not two. If I want to, I can apply BURWEN BOBCAT
processing when ripping or burning CDs. It has an efficient file converter too, that can make
128 kbps processed MP3s or lossles WMAs at high speed from hundreds of WMA files in a
folder.
DACs in computers vary in quality from good to lousy. Even computers that sport 24-bit 192 kHz
DACs may produce good or bad sound depending upon how much ground noise the DAC picks
up from the noisy computing environment. So, you don't know what sound quality you are
buying in a computer until it is too late. To assure the highest quality sound reproduction, Mark
Levinson has made available on his Daniel Hertz Advanced Audio Designs, Inc. website an
external USB (Universal Serial Bus) connected DAC with the BURWEN BOBCAT name on its front
panel. He also has available a very high quality dual 50-watt power amplifier with a USB input,
called GENIUS.
BURWEN BOBCAT RE incorporates all the slider and button settings of AUDIO SPLENDOR, but I
have set them for you, giving you a simple choice of 19 processing selections on click-buttons
for 2-channel stereo. When you listen to BURWEN BOBCAT processed audio you don't hear it
adding what sounds like room reverberation or echo. The reverberation you notice is almost
entirely that already present in the recording itself. BURWEN BOBCAT adds what I describe as
ambiance without echo. It includes a lot of what audiophiles call "air". Rough sounding
recordings become smoother and more musical because the extreme high frequency
reverberation averages out the grit. Unlike natural reverberation, which tends to obscure
transient sounds, BURWEN BOBCAT stretches transients in time so they are more easily
perceived and become clearer. After getting used to this type of processing many listeners find
their original CDs played loud are quite irritating.
Real room reverberation and ordinary electronic reverberation have their greatest effect at
middle and low frequencies. When I first discovered the benefit of my high frequency
reverberation, I tried boosting the high frequency content of various sampled reverberation
programs to obtain a similar effect. That did not work at all. No resemblance.
To produce the brilliance and clarity of BURWEN BOBCAT's high frequency reflections in the real
world, imagine a saxophone player has a wall-size reflector with a hole through which the neck
of his instrument protrudes and the reflector is only 1/4 inch from the top open valve. The
reflector is in a different position for each different note. Physical dimensions make such high
frequency reflections impossible. They have to be produced electronically. You can't get this
effect at a live concert. Yet I find quick, high frequency reflections are what your ear really likes
to hear for clear, musical sound. Even at Jordan Hall, I sometimes think the sound ought to be
processed with my new high frequency reverberation technique.
In addition to its high frequency ambiance BURWEN BOBCAT incorporates a bit of tonal
rebalancing (EQ). The four different basic selections are designed to change the overall sound
very little while making it smoother and more musical, so they are suited to all kinds of program
material. Vocal, jazz, pop, classical, and movie modify the sound more and are better suited to
fixing certain problems in recordings. Once you get used to listening to the smoother high
frequencies, unprocessed recordings become irritating to listen to. Mastering engineers tend
to use the basic selections because they don't want to tinker with the intent of the original
recording.
When I listen to my own CDs I don't mind changing the sound completely. Frankly, among the
3000 or so CDs in my collection there are very few I care to hear sounding anything like the
unprocessed recording. One reason, I am told, is many older recordings were equalized via
monitor speakers that attenuated the 3500 Hz region where voices become shrill. These
recordings now sound screechy when played through more accurate speakers.
I use AUDIO SPLENDOR to augment extreme low frequencies, attenuate piercing high
frequencies, sweeten violins, widen the acoustic image, and fill the room with spacious
ambiance via 5 speaker systems. An important lesson I learned is you need to preserve the
high harmonics of musical instruments, but a little too much makes the sound unmusical. For
poorer quality CDs and TV audio I often use what I call EXTREME processing which almost
completely substitutes artificial reverberation for the main signal at high frequencies. My latest
development at this writing is BURWEN BOBCAT MONITOR which incorporates this sound in 5.1
and 7.1 channels.
Extreme processing also includes a feature I call NO SCREECH. It attenuates the 3500 Hz region
only during a singer's loudest high notes. BURWEN BOBCAT RE vocal settings have a dip in
frequency response in the same region and make a big improvement. However, fixed
attenuation can be carried only so far before the orchestra and a singer's quieter refrains
become muffled. With No Screech in BURWEN BOBCAT EXTREME everything is clear and
screech is gone.
BURWEN BOBCAT MONITOR is my full AUDIO SPLENDOR software without the controls and is
designed to work with a MOTU 828MK3 8-channel A/D-DAC. It produces its multichannel output
from a 1 to 8 channel analog input signal or the Windows Media Player where it is a plug-in. It is
also a DirectX plug-in for professional audio editors. Audio is processed at 88.2 kHz and you can
record and play 32-bit BURWEN BOBCAT multichannel files at 88.2 kHz. You can convert a folder
full of stereo files to 88.2 kHz multichannel. In addition it includes BURWEN BOBCAT RE with all
its listening, recording, and file conversion features. For studio monitoring or broadcasting
BURWEN BOBCAT MONITOR can apply any of 7 different processings to 1, 2, or 3 stereo analog
inputs.
Read about AUDIO SPLENDOR, Dick's biography, and his sound system at www.burwenaudio.com.
Read about the Daniel Hertz Advanced Audio Designs, Inc. DAC and GENIUS power amplifier-DAC
at www.danielhertz.com.
at www.danielhertz.com.
 |