This'll be a 'living' document; I'll periodically update it with additional evaluation results on both existing and new codecs, plus additional links that I come across. So occasionally check back, and drop me an email with any feedback. Thanks!
It's unfortunately going to take me far longer than I originally anticipated
to capture and JPEG-transform the vast breadth of screen shots that I promised
in the 'Surf the Web-site WAVs' sidebar to my article. In the interim, I thought
it would at minimum be helpful if I provided you with full-size versions of the
article's Figures 2 through 6, so you could more clearly discern the differences
between them. Below, you'll find links to the graphics, in both JPEG and zipped
BMP formats.
Below you'll find links to download ZIP'd sets of the synthetic test clips I created for
this project, along with a description of each clip. Due to server storage and
bandwidth limitations, I'm providing only the 96 kHz-sampled variants; to
downsample them to 48 kHz, you can employ a full-featured program like Cool Edit
or Sound Forge, or a more focused conversion utility such as the freeware
program SoX.
| Combo (ZIP set of WAVs) |
Frequency masking test
The following half-band frequencies are at approx. -1 dBFS combined peak levels (all channels): 50, 150, 250, 350, 455, 570, 700, 845, 1000, 1175, 1375, 1600, 1860, 2160, 2510, 2925, 3425, 4050, 4850, 5850, 7050, 8600, 10750, 13750, 18775 Hz
The following quarter-band frequencies are at approx. -21 dBFS combined peak levels (all channels): 25, 125, 225, 325, 427.5, 540, 665, 807.5, 960, 1127.5, 1322.5, 1540, 1790, 2080, 2415, 2812.5, 3287.5. 3875, 4625, 5575, 6725, 8150, 10125, 12875, 17137.5 Hz
The following three-quarter-band frequencies are at approx. -21 dbFS combined peak levels (all channels): 75, 175, 275, 375, 482.5, 600, 735, 882.5, 1040, 1222.5, 1427.5, 1660, 1930, 2240, 2605, 3037.5, 3562.5, 4225, 5075, 6125, 7375, 9050, 11375, 14625, 20412.5 Hz
96 kHz sampling rate, 24-bit per-channel sample size, six channels
Right front, left surround and LFE channels are 180 degrees out of phase with left front, right surround and center channels
All frequencies are present over the entire time interval |
| Combo-20 (ZIP set of WAVs) |
Frequency masking test
The following half-band frequencies are at approx. -1 dBFS combined peak levels (left front, right surround and center channels) and approx. -21 dBFS combined peak levels (right front, left surround and LFE channels): 50, 150, 250, 350, 455, 570, 700, 845, 1000, 1175, 1375, 1600, 1860, 2160, 2510, 2925, 3425, 4050, 4850, 5850, 7050, 8600, 10750, 13750, 18775 Hz
The following quarter-band frequencies are at approx. -21 dBFS combined peak levels (left front, right surround and center channels) and approx. -41 dBFS combined peak levels (right front, left surround and LFE channels): 25, 125, 225, 325, 427.5, 540, 665, 807.5, 960, 1127.5, 1322.5, 1540, 1790, 2080, 2415, 2812.5, 3287.5. 3875, 4625, 5575, 6725, 8150, 10125, 12875, 17137.5 Hz
The following three-quarter-band frequencies are at approx. -21 dBFS combined peak levels (left front, right surround and center channels) and approx. -41 dBFS combined peak levels (right front, left surround and LFE channels): 75, 175, 275, 375, 482.5, 600, 735, 882.5, 1040, 1222.5, 1427.5, 1660, 1930, 2240, 2605, 3037.5, 3562.5, 4225, 5075, 6125, 7375, 9050, 11375, 14625, 20412.5 Hz
96 kHz sampling rate, 24-bit per-channel sample size, six channels (left front, right surround and
center channel WAVs are in the Combo ZIP set)
Right front, left surround and LFE channels are 180 degrees out of phase with left front, right surround and center channels
All frequencies are present over the entire time interval |
| Half (ZIP set of WAVs) |
The following half-band frequencies are at near-0 dBFS combined peak levels (all channels): 50, 150, 250, 350, 455, 570, 700, 845, 1000, 1175, 1375, 1600, 1860, 2160, 2510, 2925, 3425, 4050, 4850, 5850, 7050, 8600, 10750, 13750, 18775 Hz
96 kHz sampling rate, 24-bit per-channel sample size, six channels
Right front, left surround and LFE channels are 180 degrees out of phase with left front, right surround and center channels
All frequencies are present over the entire time interval |
| Half-20 (ZIP set of WAVs) |
The following half-band frequencies are at near-0 dBFS combined peak levels (left front, right surround and center channels) and approx. -20 dBFS combined peak levels (right front, left surround and LFE channels): 50, 150, 250, 350, 455, 570, 700, 845, 1000, 1175, 1375, 1600, 1860, 2160, 2510, 2925, 3425, 4050, 4850, 5850, 7050, 8600, 10750, 13750, 18775 Hz
96 kHz sampling rate, 24-bit per-channel sample size, six channels (left front, right surround and
center channel WAVs are in the Half ZIP set)
Right front, left surround and LFE channels are 180 degrees out of phase with left front, right surround and center channels
All frequencies are present over the entire time interval |
| Pink (ZIP set of WAVs) |
Pink noise
All channels are at approx. -2 dBFS peak levels
96 kHz sampling rate, 24-bit per-channel sample size, six channels
Each channel contains a unique noise pattern |
| Pink-20 (ZIP set of WAVs) |
Pink noise
Left front, right surround and center channels are at approx. -2 dBFS peak levels
Right front, left surround and LFE channels are at approx -22 dBFS peak levels
96 kHz sampling rate, 24-bit per-channel sample size, six channels (left front, right surround and
center channel WAVs are in the Pink ZIP set)
Each channel contains a unique noise pattern |
| White (ZIP set of WAVs) |
White noise
All channels are at near-0 dBFS peak levels
96 kHz sampling rate, 24-bit per-channel sample size, six channels
Each channel contains a unique noise pattern |
| White-20 (ZIP set of WAVs) |
White noise
Left front, right surround and center channels are at near-0 dBFS peak levels
Right front, left surround and LFE channels are at approx -20 dBFS peak levels
96 kHz sampling rate, 24-bit per-channel sample size, six channels (left front, right surround and
center channel WAVs are in the White ZIP set)
Each channel contains a unique noise pattern |
I've also obtained permission from Microsoft to redistribute the set of 24-bit, 48-kHz-sampled surround music files
that Microsoft supplied me at their August, 2002 Windows Media Reviewer's
Workshop, and that I mention in the 'WAV woes' sidebar to my article.
To download the source material for the Castanets, Guitar-Sax, Keys, Snaps, Tambourine and Triangle
test clips used in this project, please visit Arny Krueger's PCABX
website where you'll find two-channel WAVs in a variety of sample rates and
sample sizes. As discussed in my article, you can transform these clips into
variants similar to the ones I employed by first extending them to 30+ second playback duration through copy-and-paste waveform
repetitions within Cool Edit Pro or your favorite audio editing program. Then, duplicate the clips’
left front and right front channels to create, respectively, the left and
right surround channels, and blend the left front and right front channels to create the center and LFE channels..
At the conclusion of this project, I ended up with almost 23 GBytes' worth of
AVI, BAT, BMP, EXE, WAV and other files clogging my hard drive, organized in an
extensive directory (aka 'folder', for those of you who don't remember DOS!)
'tree'. How to archive them, get them off my hard drive and thereby free up
space again? For maximum portability to multiple computers, I wanted to employ
optical storage media instead of DSS tape...the sub-GByte storage capacity of
CD-Rs made the writeable DVD choice an obvious one. Copying files 4.7 GBytes at
a time would have been a tedious process that also would have made it a
challenge to preserve the project's original directory structure.
Instead, I decided to use backup software to accomplish the task. The Backup
utility included within Windows XP unfortunately doesn't support writing to
optical media, only to floppy discs, to archive images on the hard drive, and to
tape drives. Backup software such as Acronis's
True Image works well, but only on entire drives and partitions, not on selected
directories and files within them. I ended up using Stomp's
BackUp MyPC, which worked great. Unlike some competitors' products whose reviews
I'd researched, BackUp MyPC wrote to my Pioneer
DVR-104 (also known as the DVR-A04) at its fastest-possible speed, and I was
able to post-backup verify that everything was correctly burned to the multiple
DVD-Rs prior to deleting the files off my hard drive. The only disappointing
aspect to the software that I discovered is that it didn't seem to compress the
WAV files even remotely to the degree that the multimedia-tuned compression
algorithms in programs like FLAC, Monkey's
Audio, RAR and Shorten
can.
