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crgaston
Intermediate Member
Username: crgaston

Post Number: 140
Registered: 11-2005
Posted on Saturday, March 25, 2006 - 3:42 pm:   Edit Post

Is the damping ratio knob basically the same as a CVQ knob on a Series II?
davehouck
Moderator
Username: davehouck

Post Number: 3533
Registered: 5-2002
Posted on Saturday, March 25, 2006 - 4:19 pm:   Edit Post

I believe the answer to that question is yes.
davehouck
Moderator
Username: davehouck

Post Number: 3534
Registered: 5-2002
Posted on Saturday, March 25, 2006 - 4:24 pm:   Edit Post

According to the SF-2 manual, "the damping ratio, also referred to as "Q", works with the filter. It adds a resonant peak to the frequency selected by the Frequency Control."
strangerones
Member
Username: strangerones

Post Number: 52
Registered: 11-2004
Posted on Saturday, March 25, 2006 - 5:35 pm:   Edit Post

I've been wonrering about this knob as well.

"It adds a resonant peak to the frequency selected by the Frequency Control."

I don't know what that means.
crgaston
Intermediate Member
Username: crgaston

Post Number: 141
Registered: 11-2005
Posted on Saturday, March 25, 2006 - 6:14 pm:   Edit Post

Thanks, Dave. I was thinking that was the answer. Now I just have to pinch myself a few times to make sure I'm not dreaming. I just got my Superfilter, and am totally jazzed about (eventually) having that capability on an instrument as well. I'm finding that I'm really liking both channels as a low pass, one set around 100 and one set around 700, with the Damping Ratio knobs around 3. Those settings work great, but that's just in my basement, though...we'll see how they hold up on a stage with other people tomorrow.

James,
"...adds a resonant peak to..." is Alembic-speak for "boosts."

Charles
davehouck
Moderator
Username: davehouck

Post Number: 3538
Registered: 5-2002
Posted on Saturday, March 25, 2006 - 6:57 pm:   Edit Post

James; there's a good description of how the Q switch works with the filter here. The same principal applies to the CVQ and the damping ratio control.
the_8_string_king
Intermediate Member
Username: the_8_string_king

Post Number: 108
Registered: 9-2005
Posted on Saturday, March 25, 2006 - 10:42 pm:   Edit Post

As you roll the low-pass filter gradually from the "maximum treble" position to the other extreme, it "horizonally" filters out first the upper treble, then (also) the middle treble, then (also) the lower treble, then (also) the upper mid-range, then (also) the middle mid-range, then (also) the lower mid-range, until you reach the other extreme, at which point your left with (mainly) the lows, which are passed by the filter -hence the term "low-pass" filter (as opposed to the other filter options on the superfilter -band-pass and high-pass.)

The "Q" is a boost; it follows the filter frequency; for example, if you turn on the Q at the extreme treble position, you'll get an upper treble boost -which some refer to as "presence"; if you turn the filter a little, THAT frequency (the upper treble) -which was just boosted- is now filtered out, and the middle treble is now boosted; turn the filter a little more, and THAT frequency is now cut, and the lower treble will be boosted by the Q; turn it a little more, and THAT frequency will now be cut by the filter, and the Q will boost the upper mid-range; turn it a little further, and the upper mid-range will be filtered out, and the Q will boost the middle mid range... and so on and so forth.

I don't think Skylarks have Q switches for their filters, do they?

Of course, this description applies to the Q when used with a low pass filter; I believe it would function in the reverse in the high-pass mode.

A minor point, but I believe the superfilter "Q" is spec'ed to a maximum 12 db, whereas the Series II instruments CVQs go up to 15 db. Of course, 12 dbs of Q should be more than enough; my custom Europas Q can go up to 12 dbs, but I rarely use it at maximum.
lbpesq
Senior Member
Username: lbpesq

Post Number: 1155
Registered: 7-2004
Posted on Sunday, March 26, 2006 - 9:33 am:   Edit Post

IIRC, I believe the SF-2 covers even a wider frequency range than a Series II.

Bill, tgo
strangerones
Member
Username: strangerones

Post Number: 53
Registered: 11-2004
Posted on Sunday, March 26, 2006 - 2:02 pm:   Edit Post

I understand now. Thanks everyone :-)

I'll have to play with it some more keeping that in mind.
davehouck
Moderator
Username: davehouck

Post Number: 3544
Registered: 5-2002
Posted on Sunday, March 26, 2006 - 4:33 pm:   Edit Post

Charles and James;

Have fun with your SF-2s!

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