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| burwenaudio.com |
| QUESTIONS AND ANSWERS Dick Burwen For questions on BURWEN BOBCAT go to http://www.burwenbobcat.com/BB_Questions_and_Answers.html |
Is there a time delay through the system?
Yes. Because of the tremendous amount of audio processing, there is inherent time delay. In Options the default delay setting is 200 milliseconds for
music. We have experimentally had the delay working as short as 1.5 milliseconds for 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.
Using the most powerful laptop computer allows the shortest delays. For movies a good setting is 23 to 50 milliseconds at 88.2 kHz.
In a live performance situation, 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. In Options the default delay setting is 200 milliseconds for
music. We have experimentally had the delay working as short as 1.5 milliseconds for 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.
Using the most powerful laptop computer allows the shortest delays. For movies a good setting is 23 to 50 milliseconds at 88.2 kHz.
In a live performance situation, 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 SPLENDOR 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 it 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 was 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.
In 2004 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 offered up to 1800 watts/channel into 2 ohms in the same size. I cannot detect any change in the
sound. In 6 years of operation at 70 hrs/week, none have failed.
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 SPLENDOR 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 it 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 was 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.
In 2004 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 offered up to 1800 watts/channel into 2 ohms in the same size. I cannot detect any change in the
sound. In 6 years of operation at 70 hrs/week, none have failed.
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 are some of the uses for AUDIO SPLENDOR?
Simplified versions can be built into these and other devices:
Visit www.burwenbobcat.com for a WEB DEMONSTRATION of products directly derived from AUDIO SPLENDOR.
- 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 or Sound Forge
- Headphone listening at the office using only a laptop computer.
- Making processed music files for portable devices and cell phones.
- Broadcasting over the air, satellite, or Internet.
Simplified versions can be built into these and other devices:
- Cell phones. LG is already building BOBCAT MOBILE into 4 models that play music.
- Personal computers.
- Radios, satellite radio, TV.
- Automobile audio.
- Disc and hard drive players and recorders.
- Broadcast audio processors.
- Musical effects processors.
- Electronic musical instruments.
Visit www.burwenbobcat.com for a WEB DEMONSTRATION of products directly derived from AUDIO SPLENDOR.
What are the minimum system requirements?
- 2 GHz Intel Pentium or AMD processor
- 6 MB disk space on drive C: for installation
- Microsoft Windows XP, Vista (32-bit only), or Windows 7
- For Windows XP only, Microsoft .Net Framework 2 – may be downloaded from Microsoft at:
- Latest Windows updates
- CDROM or CD/DVD drive
- Windows Media Player 11 or 12 – may be downloaded from Microsoft at:
- For multi-channel operation: Audio Interface, MOTU (Mark of the Unicorn) 828MK3 FireWire
- Firewire cable for laptop, Comprehensive FW6PFW4P25