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 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,
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 9 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?
  • 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 32-bit 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.  
  • 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
  • 120 MB disk space on drive C: for installation
  • Microsoft Windows XP, Vista (32-bit only), Windows 7, or Windows 8.1
  • Latest Windows updates
  • Windows Media Player 11 or 12 – may be downloaded from Microsoft at:
        http://www.microsoft.com/windows/windowsmedia/player/11/default.aspx
  • For multi-channel operation: Audio Interface, MOTU (Mark of the Unicorn) 828MK3 Hybrid
How can 5 channels made from 2 can be better than 5 discrete channels?
For me, frequency response is a much more important aspect of reproduced sound than directional effects.  I find that what your ears like to hear is not
flat frequency response, but balanced average frequency response with hundreds to thousands of resonant wiggles – produced by high frequency
reverberation.  If you listen to a trumpet outdoors with its bell pointed at your ears, it sounds awful.  That is flat response with no sound reflections.

To make the trumpet enjoyable, listen to it in a reasonably live acoustic space, at an angle of 45 degrees or so off its axis.  Multiple sound reflections
from the surfaces of the room (preferably non-parallel) add and subtract at various frequencies via comb filtering to produce many hundreds of resonant
ripples in the frequency response.  That is what makes instruments sound musical.

Physical dimensions and sound absorbtion prevent significant reflections above 5 kHz in real rooms.  Artificial reverberation systems typically roll off the
high frequencies in an attempt to simulate real rooms or concert halls.  My high frequency reverberation software does the opposite – it emphasizes the
highest frequencies up to 20 kHz.  When it adds to and subtracts from the direct signal at various frequencies it produces resonant peaks and dips in the
frequency response at random intervals of frequency averaging only a few Hz apart.  The total number of peaks may be around 5000 vs hundreds for real
reverberation.

A 5-microphone system produces some of this pleasant comb filtering effect because, at your ears, rear channel sound adds to and subtracts from front
channel sound at multiple frequencies.  It also has the advantage of apparent natural placement of the sound sources.  However, since music generally
comes from the stage in front, the principal contribution from rear microphones is ambiance and overall more musical effect due to multiple resonances
when combined with front sound at the listener.

Adding my high frequency reverberation derived from two front channels into the rear and front channels is effective in producing a greater number of and
more intense desirable resonances than rear microphones.  The effect is subtle, adjustable, and makes recordings easier to listen to.  A little of the direct
sound is added into the front center and rear speakers.

Once the tools for producing my artificial high frequency reverberation were developed, it became an art to make more than 300 most listenable reverbs
each free from a few outstanding resonances that produce ringing.  I found I could control the perceived size and shape of the listening environment and
even what row you are sitting in.
My AUDIO SPLENDOR software is aimed at both listening and remastering music files in stereo or multichannel.  You make your own presets.  It has
very flexible tone controls that are independent and their dB settings all add together, producing a huge range of adjustment in tenths of a dB.  There are
313 different reverbs to choose from.  The shortest lasts only 20 milliseconds and the longest lasts 8 seconds, bigger than any cathedral.

I save my CDs on a USB drive in WMA lossless format. When played by the Windows Media Player they are continuously up converted to 88.2 kHz
WAV, processed by my software, and sent to an external 8-channel audio interface, a MOTU 828MK3.  While playing a track from an album I use 11
sliders to choose tone settings, a fixed mix selector, and a reverb button.  Normally I play 2-channel files and hear them via 5 wide range speaker
systems whose rear channels produce mostly ambiance and a little bit of the direct signal.

Altogether this system has the power of a 310-slider studio console with 357 buttons.  The control settings can be saved in the main Program Library, the
Speaker Library, or the Source Library. If desired, upon recall, all the 3 library effects can add up in dB.  Merely selecting the desired input channels
automatically creates the necessary multichannel direct and ambiance signal mixes.  Custom Mixer and RVRB Mixer settings can be saved in separate
libraries.  Recalling any of the 313 high frequency reverberation settings is a complex process. It is completely automated and recalls reverbs from the
Ambiance Normal Library.

All the control settings saved in the Program library are given a preset name which becomes a Subtitle in the Windows Media Player library.  The next
time I click on that track the Subtitle instantly recalls my entire system setup.  When setting the controls it requires calculation of 1,400,000 long formulas
to produce the sound.

Simpler Burwen Bobcat products directly derived from Audio Splendor are at
www.burwenbobcat.com.  An even simpler version was built into four LG cell
phone models.

These are good tools for teaching you what to listen for and how to counteract the bad engineering in so many of the world’s recordings, plus improving
your own speakers.
Can AUDIO SPLENDOR work on a Mac?
No.  It is a Windows program.  

The Mac problem is not as bad as it seems.  Here is how I use AUDIO SPENDOR.

First I do complete editing of 2-channel files without my software.  This can be done on a Mac or a PC.  Then I play the edited WAV file using the Burwen
Recorder-Player part of AUDIO SPENDOR in Windows.  After adjusting the sound for 5 speakers, I click the Sound button.  This makes a small preset
file containing the entire playback system setup.  In Windows Explorer, I pick up the WAV file and drop it on the Burwen Player window.  This opens the
high-speed file converter that uses the preset file to produce a 6-channel (can be 5.1), 88.2 kHz, 24 or 32-bit WAV file as final output.  This is easier than
using AUDIO SPLENDOR as a DirectX plug-in for the editor in Windows, which is another way to do it.