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| burwenaudio.com |
| Questions and Answers For questions on BURWEN BOBCAT go to http://www.burwenbobcat.com/BB_Questions_and_Answers.html |
What equipment and software are required?
You must purchase on your own the following; See Minimum System Requirements.
Notebook computer, latest version of the HP ZD8000, 1GB memory
Before purchasing, contact burwenaudio.com for information on the latest Hyperthreading Pentium 4
notebook to buy. Our software requires the most powerful computer available.
Any current version of Microsoft Office containing Excel.
Mark of the Unicorn, MOTU 828MKII Audio Interface
Firewire Cable, Comprehensive FW6PFW4P25
You must purchase on your own the following; See Minimum System Requirements.
Notebook computer, latest version of the HP ZD8000, 1GB memory
Before purchasing, contact burwenaudio.com for information on the latest Hyperthreading Pentium 4
notebook to buy. Our software requires the most powerful computer available.
Any current version of Microsoft Office containing Excel.
Mark of the Unicorn, MOTU 828MKII Audio Interface
Firewire Cable, Comprehensive FW6PFW4P25
Is there a time delay through the system?
Yes. Because of the tremendous amount of audio processing, there is inherent time delay. Burwen software
contains push-buttons to set the delay at 0.5 second for music, or 0.15 second for movies or down to 30
milliseconds for virtually perfect lip sync when watching movies. Longer delays allow you to do more things on
your computer without momentarily interrupting the audio stream. You can choose either Microsoft DirectShow
processing or the preferred ASIO for the shortest delays.
In live recording, even 30 milliseconds can be a serious delay. Audio Splendor is best suited to post processing.
Yes. Because of the tremendous amount of audio processing, there is inherent time delay. Burwen software
contains push-buttons to set the delay at 0.5 second for music, or 0.15 second for movies or down to 30
milliseconds for virtually perfect lip sync when watching movies. Longer delays allow you to do more things on
your computer without momentarily interrupting the audio stream. You can choose either Microsoft DirectShow
processing or the preferred ASIO for the shortest delays.
In live recording, even 30 milliseconds can be a serious delay. Audio Splendor is best suited to post processing.
Do I need expensive vacuum tube power amplifiers?
No!!!!! AUDIO SPLENDORTM can save you a lot of money by equalizing your speakers much better than using
the high output impedance of expensive, low-feedback, vacuum tube amplifiers. Instead buy low distortion
semiconductor amplifiers that have a lot of feedback and far more power output.
During my 60 years of designing circuits I designed a lot of vacuum tube, transistor, and switching power
amplifiers and know how each performs. In the 1950's I designed the lowest distortion vacuum tube amplifier
ever, the Krohn-Hite UF-101. It was rated at 50 Watts, 0.005% total harmonic distortion, 50 dB of negative
feedback, and sold in small quantities as a laboratory instrument for 20 years. Today I wouldn't take a vacuum
tube amplifier as a gift. Why?
What you are really buying is not quality amplification but a high distortion equalizer. The lack of feedback in
many of today's tube amplifiers gives the amplifier high distortion and a high internal output impedance,
typically in the range of 1 to 5 ohms. At some frequencies such as the fundamental cone resonance and
crossover frequencies between drivers, the load impedance of the speaker rises. The voltage divider effect
delivers more signal to the speaker terminals at these frequencies. With some amplifier-speaker combinations
the effect on frequency response is very pleasing. This load impedance effect is epitomized in the July, 2004
Stereophile review of the world's most expensive amplifier, the $350,000/pair Wavac SH-833, by Michael
Fremer with measurements by John Atkinson, page 73. The curves clearly show up to 2 to10 dB of bass boost
at 80 Hz depending upon the load impedance. The measured distortion is shameful for even the cheapest
amplifier. A vacuum tube amplifier should really be regarded as a nice piece of furniture with wires, that glows
in the dark. Use a real equalizer to improve the frequency response of your speakers!
Equalizing your speakers is not enough. Any fixed frequency response system may optimally balance the tone
on about 1 in 500 pieces of available program material. You need really flexible multichannel program
equalization to balance all the rest.
In my own sound system for 30 years I used Phase Linear 400 power amplifiers that I redesigned for lower
noise, -115 dB re 200 watts, and reduced bias drift. The 34 channels each drive 1 woofer, 1 mid-range horn,
or 9 or 12 of the 30 tweeters in each 13 foot speaker horn. With the 4-way electronic crossover the equivalent
sound level available is that of a single 20,000 watt monoblock. Before purchasing these amplifiers I
compared one with my Krohn-Hite UF-101 Ultra-Low Distortion Power Amplifier. The sounds were identical
except that the Phase Linear 400 played louder before clipping. Recently after tiring of repairing the Phase
Linears whose transistors suffered thermal fatigue, I replaced them all, purchasing 19 QSC SRA1222 dual 200
watt amplifiers. I chose these amplifiers, after measuring one unit, for their 200 watts/channel, (all my
speakers can handle), low internal impedance due to high feedback, flat frequency response, low distortion,
low noise (6 dB worse than my Phase Linears), high slew rate, switching power supply, automatic gain
reduction during clipping for reduced distortion, 3.5 inch rack panel size, 22 lb. weight, very low fan noise, and
3-year warranty. They cost under $1000 each and for somewhat more money QSC offers up to 1800
watts/channel into 2 ohms in the same size. I cannot detect any change in the sound.
That is the sort of amplifier I suggest for you and there are plenty of other good amplifiers from other
manufacturers in the professional area. And forget expensive cables. They are inaudible furniture.
No!!!!! AUDIO SPLENDORTM can save you a lot of money by equalizing your speakers much better than using
the high output impedance of expensive, low-feedback, vacuum tube amplifiers. Instead buy low distortion
semiconductor amplifiers that have a lot of feedback and far more power output.
During my 60 years of designing circuits I designed a lot of vacuum tube, transistor, and switching power
amplifiers and know how each performs. In the 1950's I designed the lowest distortion vacuum tube amplifier
ever, the Krohn-Hite UF-101. It was rated at 50 Watts, 0.005% total harmonic distortion, 50 dB of negative
feedback, and sold in small quantities as a laboratory instrument for 20 years. Today I wouldn't take a vacuum
tube amplifier as a gift. Why?
What you are really buying is not quality amplification but a high distortion equalizer. The lack of feedback in
many of today's tube amplifiers gives the amplifier high distortion and a high internal output impedance,
typically in the range of 1 to 5 ohms. At some frequencies such as the fundamental cone resonance and
crossover frequencies between drivers, the load impedance of the speaker rises. The voltage divider effect
delivers more signal to the speaker terminals at these frequencies. With some amplifier-speaker combinations
the effect on frequency response is very pleasing. This load impedance effect is epitomized in the July, 2004
Stereophile review of the world's most expensive amplifier, the $350,000/pair Wavac SH-833, by Michael
Fremer with measurements by John Atkinson, page 73. The curves clearly show up to 2 to10 dB of bass boost
at 80 Hz depending upon the load impedance. The measured distortion is shameful for even the cheapest
amplifier. A vacuum tube amplifier should really be regarded as a nice piece of furniture with wires, that glows
in the dark. Use a real equalizer to improve the frequency response of your speakers!
Equalizing your speakers is not enough. Any fixed frequency response system may optimally balance the tone
on about 1 in 500 pieces of available program material. You need really flexible multichannel program
equalization to balance all the rest.
In my own sound system for 30 years I used Phase Linear 400 power amplifiers that I redesigned for lower
noise, -115 dB re 200 watts, and reduced bias drift. The 34 channels each drive 1 woofer, 1 mid-range horn,
or 9 or 12 of the 30 tweeters in each 13 foot speaker horn. With the 4-way electronic crossover the equivalent
sound level available is that of a single 20,000 watt monoblock. Before purchasing these amplifiers I
compared one with my Krohn-Hite UF-101 Ultra-Low Distortion Power Amplifier. The sounds were identical
except that the Phase Linear 400 played louder before clipping. Recently after tiring of repairing the Phase
Linears whose transistors suffered thermal fatigue, I replaced them all, purchasing 19 QSC SRA1222 dual 200
watt amplifiers. I chose these amplifiers, after measuring one unit, for their 200 watts/channel, (all my
speakers can handle), low internal impedance due to high feedback, flat frequency response, low distortion,
low noise (6 dB worse than my Phase Linears), high slew rate, switching power supply, automatic gain
reduction during clipping for reduced distortion, 3.5 inch rack panel size, 22 lb. weight, very low fan noise, and
3-year warranty. They cost under $1000 each and for somewhat more money QSC offers up to 1800
watts/channel into 2 ohms in the same size. I cannot detect any change in the sound.
That is the sort of amplifier I suggest for you and there are plenty of other good amplifiers from other
manufacturers in the professional area. And forget expensive cables. They are inaudible furniture.
What processor is required.
The present software programs use all the processing power an Intel Hyperthreading Pentium 4 processor can
muster. Each program consists of two parts: a set of Microsoft Excel workbooks that calculates and stores filter
using filter coefficients from Excel.
Versions using less than 7.1 channels, fewer tone controls, and short reverberation can use much less
processing power. The C++ program automatically adapts to the number of channels of audio available and
the number of filters and sound reflections, using minimum processor resources in each case. A highly
simplified version in 2 channels can be small enough for use on the lowest cost computers..
The present software programs use all the processing power an Intel Hyperthreading Pentium 4 processor can
muster. Each program consists of two parts: a set of Microsoft Excel workbooks that calculates and stores filter
using filter coefficients from Excel.
Versions using less than 7.1 channels, fewer tone controls, and short reverberation can use much less
processing power. The C++ program automatically adapts to the number of channels of audio available and
the number of filters and sound reflections, using minimum processor resources in each case. A highly
simplified version in 2 channels can be small enough for use on the lowest cost computers..
Here are some of the uses for the present full versions of AUDIO SPLENDORTM , OPTIMUM AMBIANCETM, and
SPLENDOR & AMBIANCETM.
Remixing and cleaning up old 2 channel recordings to produce multichannel SACDs and DVDs by adding
ambiance into all channels.
High end consumer audio and video systems.
Consumer audio and video recording.
Digital audio workstation
Studio mixing console.
Central media systems for home or office - separate remote control and stored compensation for each
room.
Movie theaters.
Music download enhancement.
A plug-in for studio mixing software such as Sony's Vegas + DVD.
Headphone listening at the office using only a laptop computer.
New ambiance programs can evolve in the future from a community of audio engineer users
The next list of uses requires simplified versions of Burwen software.
Personal computers.
Portable music devices.
Radios, satellite radio, TV.
Automobile audio.
Disc and hard drive players and recorders.
Broadcast audio processors.
Musical effects processors.
Electronic musical instruments.