[sdiy] Frequency Counter Software

[Peter Grenader]

I agree with Grant here.  In the world according to Peter the stability of
analog VCOs is very over-rated, sadly too often being the deciding factor
for many.  Read anything you wish into this, but let me just say that my
VCOs performed on par with the best I had to test against at the time,
including the Wiard, Blacet, Analogue Systems, Analogue Solutions,  Doepfer,
Steiner, Serge, but hey - mine still go out of tune after a few hours.  My
expo converter (Linear Systems LS312) has very impressive temperature
characteristics and it literally straddles the tempco which tucks in flush
with the expo's underbelly. .  But in the end, they're analog and meet that
expectation.  I could have spent a fortune I guess doing everything
technically possible to keep them in tune a bit longer but that would have
had to be passed on to the end user ($$) and at that point, they could have
purchased an entire VA system.  After much deliberation, my conclusion was
it's a musical instrument, not a piece of test gear and it shouldn't be
expected to behave as one.

Let me close with a quote from my buddy Wendy Carlos, who in an reply to me
mentioning to her I had recently begun to market analog instruments (gulp!),
made the following judicious proclamation:

"No older tech is ever completely replaced in the arts and sciences related
to the arts. I think that a savvy design could get analog to work very
reliably...Digital has many advantages, and also some disadvantages. You
know you're still alive if you realize that everything IS a compromise, the
human/universe condition"

- P


Grant Richter wrote:

The human ear is evolutionarily adapted to the human voice, which is
extremely unstable.
The possibility of "nimble" pitch sources with extreme stability are only
recently available (perhaps 100 years).
At this point, they do not have any real significance in terms of the
"History of Music".

Buchla's famous comment (attributed) that his VCOs didn't have to be tuned
any more often than a violin,
is perfectly reasonable in the context of musical instrument history.

Absolute experts (such as Mr. Ian Fritz) have researched analog oscillator
stability to the point where
it rivals DSPs. A very difficult and impressive engineering success. But
only an engineering success.

Ultra-stable oscillators, by themselves, have not produced a musical
revolution, because even highly
unstable acoustic sources are "good enough for jazz".

And yes, Mr. Loffink, I do know that precise oscillators allow micro-tuning
and the good things that go with it.
So do Gamelan Metalophones and Sitars / Tamburas.

On Oct 10, 2005, at 9:37 PM, Amos wrote:

I have taken absurd pains to tune a 3-VCO synth to utter unison, to the
point of manually phase-aligning the waves for minimum cancellation... only
to be told that the end result was too "cold" and "digital-sounding."
 
 there seems to be a limit to the amount of "accuracy" some people want out
of a musical system!
 
 Seb: thanks for the plugin recommendation.

On 10/10/05, Seb Francis <seb at burnit.co.uk> wrote:
 To answer my own question ...

I've tried a few different frequency counter / spectrum analyser / scope
softwares (hopefully 'softwares' is acceptable english ;)
They all use FFT to get the frequency and don't seem to be very accurate
- they jump around by a few hertz even with a stable input.

But thinking along different lines, I found this great little VST plugin
"C-Tuner"
 http://mitglied.lycos.de/moritz_48/Free-VST/cplugs11.ZIP
<http://mitglied.lycos.de/moritz_48/Free-VST/cplugs11.ZIP>

In 'super-accurate' mode it measures to 0.1 cents.

Testing with a soft-synth showed the expected 0.0 cent error
Testing with my nord lead (digital) hardware synth showed a consistent
error of +0.4 cent across the whole keyboard .. I can live with that :)

Interestingly when I hooked up my MOTM VCOs, although they tracked well
(within 5 cents across the whole keyboard - perhaps could be even better
if I bothered fine tuning the trimmers a bit), both the 300 and 310
showed a jitter of approx 2 cents.  This is not my MIDI2CV converter by
the way - the jitter is still present even with nothing plugged into the
CV input.

Now I'm not complaining: this is probably much better than most other
VCOs (and actually one of the plus points of analog is the inaccuracy),
but I make my point again about MIDI2CV converter accuracy - what
benefit is there in having better than 1 cent accuracy if even a
super-stable MOTM VCO is not this accurate.

Anyway, now off to tune my newly built Oakley 3031 .. which was what
started all this in the first place!

Seb




ryan williams wrote:

> thats a good idea. I had been tuning VCOs by doing this:
> run a soft-synth at some frequency. also output the MIDI value to your
> MIDI->CV converter. mix that with the VCO and listen to beats to get
> the offset correct. then go up 2 octaves and adjust the scaling,
> repeat. Sure this is a common method, but it shouldn't be too hard to
> make a frequency counter (did one with an 8bit uC once). A neat
> program would be something that plays a reference frequency mixed with
> the VCO output and displays the VCO frequency at the same time. I
> think I'll write this program. It'll be atleast 2 weeks though.
>
> -ryan
>
> Seb Francis wrote:
>
>> Hi,
>>
>> Can anyone point me in the direction of an accurate (and preferably
>> free) frequency counter software for windows.
>>
>> It seems to me that this would be a very accurate and easy method of
>> tuning VCOs (especially since my sound card is clocked from a dead
>> stable RME A/D D/A interface).
>> 
>> Seb
>
>
>
>