Alembic Guitars Club

Alembic products => Alembic Basses & Guitars => Topic started by: crgaston on March 25, 2006, 03:42:01 PM

Title: SF2 Question
Post by: crgaston on March 25, 2006, 03:42:01 PM

Is the damping ratio knob basically the same as a CVQ knob on a Series II?

Title: SF2 Question
Post by: David Houck on March 25, 2006, 04:19:45 PM

I believe the answer to that question is yes.

Title: SF2 Question
Post by: David Houck on March 25, 2006, 04:24:04 PM

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.

Title: SF2 Question
Post by: strangerones on March 25, 2006, 05:35:14 PM

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.

Title: SF2 Question
Post by: crgaston on March 25, 2006, 06:14:26 PM

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

Title: SF2 Question
Post by: David Houck on March 25, 2006, 06:57:59 PM

James; there's a good description of how the Q switch works with the filter here (http://club.alembic.com/index.php?topic=271).  The same principal applies to the CVQ and the damping ratio control.

Title: SF2 Question
Post by: the_8_string_king on March 25, 2006, 10:42:53 PM

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.

Title: SF2 Question
Post by: lbpesq on March 26, 2006, 09:33:39 AM

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

Title: SF2 Question
Post by: strangerones on March 26, 2006, 02:02:42 PM

I understand now.  Thanks everyone  
 
I'll have to play with it some more keeping that in mind.

Title: SF2 Question
Post by: David Houck on March 26, 2006, 04:33:34 PM

Charles and James;
 
Have fun with your SF-2s!