Doepfer

I'm trying to tune my A-110s to very precise frequencies and I'm assuming I'd need some 
(probably digital?) device to be able to get one at say 587 Hz and the other at 845Hz. What 
devices do people use to get exact tunings with analog oscillators?

I'm sure there is something very simple that performs this function, I just don't know what 
it's called or where to find it?

someone help?

Thankyou hugely for your time.

You need a mixer module and a fixed voltage (e.g. any active output of
a step sequenser). The A-138c mixer module has a fixed voltage on
input 1 if no patch chord is inserted.

What you do is simply scale down the fixed voltage and then insert
that into the CV2 input of the A-110. The CV2 pot is now your fine
control. 

Best Dirk.



--- In Doepfer_a100@yahoogroups.com, "redsawcloud" <redsawcloud@...>
wrote:
>
> I'm trying to tune my A-110s to very precise frequencies and I'm
assuming I'd need some 
> (probably digital?) device to be able to get one at say 587 Hz and
the other at 845Hz. What 
> devices do people use to get exact tunings with analog oscillators?
> 
> I'm sure there is something very simple that performs this function,
I just don't know what 

> it's called or where to find it?
> 
> someone help?
> 
> Thankyou hugely for your time.
>

On 19 Nov 2006, at 3:12, redsawcloud wrote:

> I'm trying to tune my A-110s to very precise frequencies and I'm assuming I'd need some 
> (probably digital?) device to be able to get one at say 587 Hz and the other at 845Hz. What 
> devices do people use to get exact tunings with analog oscillators?

Wavelab's FTT-meter is a nice visual aid for precision tuning. You 
can zoom in quite a bit.

> I'm trying to tune my A-110s to very precise frequencies and I'm 
assuming I'd need some 
> (probably digital?) device to be able to get one at say 587 Hz and 
the other at 845Hz. What 
> devices do people use to get exact tunings with analog oscillators?
> 
> I'm sure there is something very simple that performs this 
function, I just don't know what 
> it's called or where to find it?

A 'frequency counter' or a 'universal counter timer' *might* do the 
job for you, but you need to be careful - they are frequently 
specified to operate over a large range, say 5Hz to 5MHz, so getting 
an accurate reading (i.e. less than a hertz) at low (audio) 
frequencies can be quite a challenge! I have a second-hand (and 
rarely used) Racal-Dana 9902: don't know where you are based, but 
there are loads out there, see for example:

http://www.telford-electronics.com/the_graveyard.htm

- these are the people in the UK where I got mine from.

Most have two modes of operation: for higher frequencies they count 
the number of cycles of the applied signal over a known (fairly 
small) time interval - for low frequencies this will not be very 
many, hence the inaccuracy; so for lower frequencies it works the 
other way round - it counts the number of cycles of an internal clock 
during one period of the applied signal, and then displays the 
_period_ of the signal, and hence you have to invert to get the 
frequency (fiddly, but you do get a more accurate measurement of low 
frequencies this way).

Another alternative would be to try and use a 'chromatic tuner': I 
have a Seiko ST-747, which has a range from A0 (27.5Hz) to C8 
(4186Hz), and which displays the deviation +/- (up to) 50 cents from 
the nearest semitone. Thus again, in theory, with a little maths you 
can work out the exact frequencies. Claimed accuracy is +/-1 cent.

With the counter reading a frequency of 848.2Hz, a period measurement 
gave 1179us = 848.18Hz, the tuner was saying G#+35 cents = 
(nominally) 830.61 * 2^(35/1200) = 847.57Hz (and I say 'nominally', 
as this figure is from a book, and not what the tuner might be 
calibrated to!).

My conclusion: just about do-able, but if you want readings around 
the 'tenth of a hertz' region, you will probably have to work at the 
maths a little bit!

Tim

It seems as if there could be some shareware download someplace that could do this?