[sdiy] Experiment with bandlimited ramps

[Seb Francis]

Tom Wiltshire wrote:
>
>
> Chuckle chuckle! Be very careful here, young jedi!
>

;)

> I did a similar recording. In my case, I recorded a single ramp wave 
> from my Pro-One (pair of CEM3340 ramps) and compared it with a pair of 
> bandlimited ramps from my dsPIC DWGS oscillator (which only has 64 
> harmonics incidentally).
> Have a listen to that and see what you think:
>
> http://www.electricdruid.com/ProOneShort.aiff
>
> http://www.electricdruid.com/ProtowaveShort.aiff
>
> There's some difference in the beat frequency between the two sets of 
> oscillators, but in terms of actual sound quality, I was pleased with 
> the digital version. Perhaps the fact there are two oscillators hides 
> the digital sterility?! ;)
> To be honest, I got all "engineer" about it, and decided that "good 
> enough" probably is just that, even if there is some 
> tiny/subtle/measurable difference.
>

Well I'm back on my laptop again so difficult to hear anything properly, 
but they do sound pretty close.  If anything I'd say the ProOne sounds 
slightly thinner (normal for a ProOne).  But then I shouldn't really be 
making judgements on such an emotive subject using my laptop speakers!

I do agree with the "good enough" approach, perhaps more from an 
artistic point of view than as an engineer - for example while there is 
a noticeable, if subtle, difference between 150 and 100 harmonics for a 
bass tone, do these extra 50 high & quiet harmonics make the sound more 
musically useful or pleasant.  I would say not ... but this is of course 
a subjective matter.

Seb