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Topic: FM synth implementation of chorus effect (Read 7197 times) previous topic - next topic

FM synth implementation of chorus effect

Hi, I have been trying to learn how to program my sound card. I have been successful at reading midi files and programming my sound card's fm synthesizer so that it gives a rough estimation of the way the music is supposed to sound. For simple midi's my little routine seems perfectly adequate, but for more complex songs it is painfully clear that more needs to be done.

I have been trying to find out how chorus control is programmed into the FM synthesizer. If anyone can explain chorus effects on attack, decay, sustain, and release or any other relevant attributes of the FM synth, I would be most thankful.

Re: FM synth implementation of chorus effect

Reply #1 –
Unfortunately, the FM synths (SB16 compatibles, AdLib, etc.) do not support chorus, reverb or expression. Channel volume is implemented, but rather poorly; there isn't much change until you get near the bottom, then the volume changes abruptly.

Even pan is badly implemented, only panning to about six discrete position, IIRC. So you can't do a smooth pan, it will always sound stepped and choppy.

The best idea is to dump the FM synth entirely. It's perfectly adequate for background noise in games (which was its primary intent), but is practically useless for serious music work.

Although, with the interest in retro synthesisers, I'm sure it won't be long before someone writes a concerto for SB16 FM synth. ;-)

Fred

Re: FM synth implementation of chorus effect

Reply #2 –
Re Fred's comment: I wonder if John Cage's 4'33" would be suitable?

Seriously, however, decent wavetable cards are very inexpensive these days. Rather than spend hours trying work arounds with an FM card, I would urge you consider getting a different card. The SoundBlaster Live (Value) is a well-supported, highly used and inexpensive card. (I do not know what kind of computer you have, but if it is less than three or four years old and has a PCI slot, should be able to carry the soundblaster).

Re: FM synth implementation of chorus effect

Reply #3 –
4min33s should be ok :)
(Note: 4'33'' is an angle measure, not a duration, if you want to respect standard abbreviations)

About SBLive: inexpensive? The first time I saw one, its value was about 300 USD (1800FRF). Hope it's not so expensive now.
Does it have its own memory, or does it use the "main" memory, btw?

Re: FM synth implementation of chorus effect

Reply #4 –
SBLive 5.1 is about £30 (+VAT). It does use main memory.

And perhaps 4'33" is correct - it's a little known fact that the title was actually a reference to the angle by which the sustain pedal had to be depressed to achieve the authentic performance.

Peter

Re: FM synth implementation of chorus effect

Reply #5 –
Thanks for all the help! That will save me some serious future headaches!

I'm sure I will get a new sound card sometime in the near future.

Re: FM synth implementation of chorus effect

Reply #6 –
about a new card: be sure that the driver is available for the combination of your version of operating system(s) and the card you plan to buy.
Never believe a seller on his/her sole words.

And finally ask if you return the product back if not suitable to your PC configuration (it happens)

HTH!

Re: FM synth implementation of chorus effect

Reply #7 –
Will do.

The beast I have now is a strange one anyway. It is, I think, a Crystal Logic card that supports two modes of operation: Windows Sound System and Sound Blaster Pro compatible. I think the Windows Sound System is significantly more advanced since Winamp will play at high quality the Bohemian Rhapsody sample midi I have been working with. Unfortunately I can't use the Windows Sound System mode since the application I am developing for will not be under Windows.

Re: FM synth implementation of chorus effect

Reply #8 –
Quick note on sound card costs and then I'll be quiet.

SB Live (Value) can now be readily obtained for less than $ 70 U.S.

If downloadable soundfont capacity is not needed, I have always liked the wavetables on the Ensoniq PCI. Those are available for around $ 20 US.

The Yamaha XG's are also pretty good and can be acquired quite cheaply.

Not sure where you are located, but some good deals can be found on ebay (provided you only buy from folks who have good ratings)

Re: FM synth implementation of chorus effect

Reply #9 –
John Cage's 4'33" was also 4 mins 33 seconds long.
Ev