[Ham-Computers] RE: Cakewalk Software

Mon, 17 Jun 2002 00:29:44 -0700

Cakewalk is used to compose/record MIDI files.  The quality of the synthesizer used to playback the MIDI file dictates the audio quality of the final output.  Also, although MIDI files are almost universally compatible with all MIDI playback equipment, whether a particular MIDI device supports a specific MIDI function - voice or command - is device dependent.

For PC's, your soundcard dictates the playback quality.  The original PC sound card, the Adlib, used a Yamaha 2-op FM synthesis chip and sounded like many older Yamaha keyboards.    Creative took the Adlib design, added a DAC for digitized sound playback, and thus the Sound Blaster was born.  Over the years, 3-op FM synthesis and, finally, digitized sound samples (aka "wavetable synthesis") were used for MIDI playback.

Most FM synthesizers sound the same, but digitized sounds are completely based on the quality of the instrument and eqiupment that was used to record the actual sound.  For years, sound card manufacturers rallied behind different "professional" keyboard companies and incorporated their sound samples in the card.  Creative purchased Ensoniq for this purpose, MediaVision used Korg samples in their last products, and most generic sound cards using a Yamaha chipset used, well, Yamaha XG samples.  Unfortunately, if you compose something on your computer and it sounds a certain way, it may not sound the same on another person's PC due to the different synthesizers used on PC sound cards.  Eventually, Microsoft incorporated Roland's basic 4MB MIDI sample set as part of DirectX so most systems with DirectX installed at least use the same instrument samples (and the quality of the playback is then dependent on the quality of the DAC).

Today, the number of polyphonic "voices" a sound card supports in hardware usually dictates the perceived sound quality.  Most PCI adapters support 64 "hardware" voice "streams" - you can say it's similar to a 64-track recording board.  Most cards can support additional "synthesized" voices by using the PC's CPU to create and mix the sounds and output them via one of the hardware channels.  These "virtual" voices come at the expense of sound quality.  Duane, it is entirely possible that this is the situation you've run into - your composition has reached a complexity level that requires more than the number of hardware channels available and is "virtualizing" additional voices.

Please note that each MIDI "track" isn't dedicated to voice channel - It is often software dependent and the software will usually just find the first channel available to play the next note.  So the number of tracks you've laid down may not really be affecting the sound quality...it's really the added complexity of the overall score that may be factor.

One more thing.  Older sound cards only have a limited number of hardware DAC channels available (e.g. the original SoundBlaster only has 1).  Adding additional hardware channels was expensive and Yamaha developed the "Soft" synthesizer.  This is the "virtual" synthesizer mentioned earlier.  So if you have an older sound card, or, if if you have a generic sound card that used a "soft" synthesizer to save on costs, then the audio quality will definitely drop as additional sound voices are needed.  For example, my current sound card (a TurtleBeach Montego II) supports 64 hardware voices and upto 576 total voices (512 "soft" plus the 64 "hard).  I have it set to only support a max of 64 voices, so I know the sound quality never suffers, so to speak.  Most really can't tell the difference between the "soft" and "hard" synthesizer voices (especially gamers), but if you're a musician or have a good ear, the difference can be noticeable.

One thing you might want to check is which device on your soundcard is being used to playback MIDI streams.  On systems with DirectX installed, the Microsoft DirectX Synthesizer is the default device.  All "consumer" grade sound cards also have an Adlib compatible FM synthesizer for backwards compatibility.  In addition, it may also have it's own hardware synthesizer.  Always make sure the "best" synthesizer is in use on your soundcard for MIDI playback.  Microsoft's DirectX MIDI sample set isn't bad, but your sound card's native set may be better (or worse!).  The DirectX set is 3MB in size and is by Roland.  The 8MB Yamaha set sounds much better, but the 1MB or 2MB Yamaha set is pretty crappy.  Creative's Ensoniq EMU MIDI set is very common as many have a Creative card of some sort.  There are also may downloadable sound sets available on the 'net and many sound cards have a utility to "load" these sets (they have a .DLS extension - DirectX's file is "GM.DLS").

The DirectX diagnostic tools allows you to get an idea of how your sound card's wavetable set compares with DirectX's wavetable set.  Goto C:\Program Files\DirectX\Setup and run the DXDiag tool.  Under the "Music" tab, you'll find a way to select the MIDI port currently used and a "test" button.  Select the Microsoft Synthesizer and press "test".  They switch the MIDI port to "MIDI Mapper" or the card's synthesizer port to hear the difference (there may not be one if your card uses the same wavetable set as DirectX).  If you select the MPU-401 port, then you'll hear nothing unless you have an external MIDI processor connected to the soundcard's MIDI expansion port.  To pick the one you like the best as the default MIDI playback device, goto the Windows Control Panel, Multimedia, MIDI tab, and highlight the synth you want to use.  Microsoft's synth is not available as it's only available via DirectX calls.  QuickTime also has it's own wavetable set, MIDI files will sound different when played back with QuickTime.

And, as usual, I ramble - Sorry!.  If you're even more confused now than before, feel free to contact me.

73,

  - Aaron Hsu, NN6O
    (athsu)@unistudios.com
    (nn6o)@arrl.net
    No QRO-Int'l #1,000,006

-----Original Message-----
From: Duane Fischer, W8DBF [mailto:[email protected]]
Sent: Sunday, June 16, 2002 5:07 PM
To: [email protected]
Subject: [Ham-Computers] Re Cakewalk Software

Have any of you used the Cakewalk software to record with? Although it is
supposed to handle sixteen tracks, there seems to be a drop off in audio quality
after eight tracks. Does anyone know anything about this?	

Thanks.	

Duane W8DBF	
[email protected]	