[Fpga-synth] Oscillator Sync to gate

[Dave Manley]

Magnus Danielson wrote:
> Eric,
> 
> Eric Brombaugh skrev:
>> Here's another little philosophical question:
>>
>> If you've got a simple synth with a standard signal flow:
>>
>> pitch cv -> osc -> vca -> out
>>                     ^
>>                     |
>> gate ----> adsr ----+
>>
>> is there any advantage to syncing the osc to the gate such that you 
>> get the same initial phase on every strike of the note? It seems the 
>> typical configuration of a modular synth will not try to do this, 
>> choosing instead to let the oscillator run free. Perhaps commercial 
>> (digital) synths do this?
>>
>> Advantages of sync would be to get identical waveforms every time you 
>> hit that note. Disadvantage would be that you get identical waveforms 
>> every time >grin<. I suppose it depends on how much variation you're 
>> looking for.
>>
>> What's your preference?
> 
> Don't do it!
> 
> For most parts, I see no point in it.
> 
> However, when considering sounds where attack is essentially imminent, 
> similar to hitting a bell or some other resonance, it might be important 
> to get consistent transient. That's at least when it would make sense.
> 
> For slower attacks I would say that if there is an effect, it reduces 
> significantly as attacks becomes longer.
> 
> The middle path is to allow it to be routeable, but not default.
> 
> Now at least you know when I think it may be worth it, if it ever is...
>


In the interest of stating the obvious, and writing a long run-on 
sentence with lots of commas, the answer can be completely different if 
you were talking about a modulation oscillator, where depending on what 
you wanted to achieve, and the speed of modulation, you may indeed want 
to sync the modulation oscillator, but since your diagram shows this 
isn't the case, go ahead and ignore this message.

What are you doing for LFOs?  Do you use the same NCO as you do for 
audio samples?  How slow can the NCO run, and how deep is your look-up 
table, and at what point do you have to add more bits of address?

-D