Q values for equalizer. How does it measure?

[gorman]

I read the manual and I understand that a smaller value affects a narrower set of frequencies but... on what unit of measure?

[Llorean]

Q is a specific term relating to equalizers. As far as I know, "Q" actually is the unit of measure (more or less) and the range it covers depends on the frequency it's centered around. That being said, I don't use it often, and more detailed information would probably best be sought with Google, as it is a more or less standard term.

[gorman]

Q is a specific term relating to equalizers. As far as I know, "Q" actually is the unit of measure (more or less) and the range it covers depends on the frequency it's centered around. That being said, I don't use it often, and more detailed information would probably best be sought with Google, as it is a more or less standard term.

Ooops, I didn't know this. I was used to the Rio Karma parametric equalizer that used a different terminology. It would be nice to fill in details in the manual about this, as it's pretty mysterious to uninitiated.

[Llorean]

As always, we welcome patches and updates to the manual from anyone interested. Everyone who works on Rockbox is just a person volunteering some of their spare time and the same applies to the manual.

[gorman]

As always, we welcome patches and updates to the manual from anyone interested. Everyone who works on Rockbox is just a person volunteering some of their spare time and the same applies to the manual.

I know, I was thinking this while I typed the previous message. If I'll manage to wrap my head around this I'll try to contribute.

Thanks a lot for the help.

[saratoga]

As I recall, Q is just the inverse of the fractional bandwidth of a filter or other linear system. So a Q of 2 means a fractional bandwidth of 50%.  I haven't played with it in Rockbox, but I assume a Q of 2 in a 1KHz center frequency filter would mean you'd have a passband extending out 500Hz in both directions.

[Chronon]

Nice summary, saratoga: This means that a small Q corresponds to a broader spectral width.

Imagine a peak in the gain (vs. frequency) spectrum.  The fractional bandwidth refers to the width of this peak divided by the center frequency of this peak.  Q factor refers to the reciprocal of this as saratoga said.