Micropitch Pitch knob vs. H910 H949 Pitch knob

[joegrant413]

Hi,

I have an H9, and here’s my question:

In the Micropitch algorithm, “Pitch A” goes from 0 to 50 cents. Straightforward enough if you know that a cent is 1/100 of a semitone.

In the H910 H949 algorithm, when I set “Pitch Cntrl” to “Micro”, Pitch A goes from 0.908 to 1.092 for “Pitch A”. The manual tells me that this value is a pitch ratio. Now I’m confused. If this setting is, say, 1.001, is that 0.1 cent above unison? And if that’s true, then the H910 H949 would have finer control than Micropitch. But that wouldn’t seem right. I suppose it would make a lot more sense to me if this algorithm’s Pitch Cnt was also just straight cents. 

So could someone please explain what H910 H949 “Pitch A” and “Pitch B” knobs really mean? 

It is especially baffling if I’m trying to set it to something similar in “MicroPitch”.

Thanks,

– Joe

[brock]

joegrant413 wrote:

… In the H910 H949 algorithm, when I set “Pitch Cntrl” to “Micro”, Pitch A goes from 0.908 to 1.092 for “Pitch A”. The manual tells me that this value is a pitch ratio. Now I’m confused. If this setting is, say, 1.001, is that 0.1 cent above unison? …

It’s 2 different ways of measuring the same thing.  Like expressing temperature in either Farenheit or Celsius.

One way to compare frequency ratios to cents is by switching to the H910 / H949 CHROMATIC mode.  A minor 2nd up from unison rounds to 1.060.  That same semitone would be 100 cents up.  So the MICRO mode of the H910 / H949 algorithm ranges upward to a 1.092 ratio, or about 152 cents.  The downward 0.908 ratio is about -167 cents (down).  A little more than a semitone + a quartertone in either direction.

Quote:

… And if that’s true, then the H910 H949 would have finer control than Micropitch …

I’d call it a 3X wider range of pitch shift.  You can get even wider by using the NORMAL mode.  It seems to me that the MICRO mode – and MicroPitch algorithm – devote more processing power to pitch accuracy for smaller shifts.  And the frequency ratios to 3 decimal points are roughly twice as coarse as a range defined in cents.

The MicroPitch algorithm can double to 100 cents in either direction [by latching the Flex / Performance switch], and adds LFO modulation for a semi-independent pitch modulation.  The H910 / H949 algo features classic rack unit ‘modeling’, with multiple splicing techniques, and glitching characteristics (or not).  Both can produce similar effects within a narrow range of equivalent pitch shift.

Quote:

… But that wouldn’t seem right. I suppose it would make a lot more sense to me if this algorithm’s Pitch Cnt was also just straight cents …

Eventide went with historical accuracy for the H910 / H949 algorithm.  Frequency ratio was the unit of measurement used on the original rackmounts.  It’s 12-tone Equal Temperament.  This deviation from unison pitch, expressed as a ratio, can have an equivalent in semitones.  So can a certain number of cents.  I agree that it can be easier to think in cents and semitones.  Frequency ratio and cents can be converted back & forth.

[joegrant413]

Thank you! I really appreciate the detailed reply.

– Joe

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