SF-2 frequency filter ranges?

[cosmic]

I looked around and could not find the information about the Sf-2 frequency ranges.
 
I did find info on the site and assume the low pass on the Sf-2 is similar to the bass control low pass filters and is in the range of 350Hz to 6KHz. Is this correct?
 
But more importantly to me, at this point, is  what is the range for the high pass filter and the bandpass filter?
 
Thanks ahead of time.....

[mica]

The range is the same for all filter modes on the SF-2, 45Hz - 6KHz.

[cosmic]

thank you for the information.
 
That is interesting that the lowest fequency is 45Hz.
 
An open E is around 41Hz and an open B even lower at 31Hz.
 
Does this mean when you use the fliters you will lose the fundamental of the low E or B? It appears by the specs you will not pass these through. I am curious as to how that works and as to why the filter does not have a lower cut-off point?
 
Please excuse my ignorance ahead of time. I have a filter pedal for guitar, and am interested in getting something for my bass.
 
(Message edited by cosmic on December 07, 2005)

[David Houck]

In the low-pass setting, when you turn the knob all the way to the lowest position at 45Hz, then the filter is passing frequencies below 45Hz and blocking frequencies above 45Hz (plus the rolloff).  Thus the low-pass filter always passes 41 and 31.
 
From a previous thread:
 
Simply put, the low pass filter works the same as the filter on your bass, it lets through all frequencies below the point at which you set it. The high pass filter is the opposite, it lets through all frequencies above the point at which you set it. The band pass filter lets through only the particular frequency at which you set it.
 
See also the Must Reads post.

[cosmic]

Right, I understand that part. I am wondering in the high pass mode -- if you put it to the lowest setting of 45Hz -- you'd be blocking 41 and 31. How is the high pass very useful in that regards?

[edwin]

The high pass is useful for all kinds of things. In fact, I think you'd be moderately hard pressed to find speaker systems that would recreate much below 45 hz. I usually use the HP mode to bring in high frequencies (1khz and up).
 
Edwin

[dadabass2001]

Not trying to be a mensch, but isn't a high pass filter by definition not treating with extended low frequency response? Low frequency is the realm of the low pass filter. These separate filter outputs (along with whatever you decided to treat with the band pass) are summed together at the output. the whole frequency range can be addressed.
Mike

[crgaston]

Cosmic, while you could do that, it wouldn't makes much sense.  Theoretically, (I don't have one of these, but have been trying to understand them for a while) you could set the lowpass at say, 45Hz, and the hipass at around 850. These then get blended together in whatever ratio you want, and boom, you have a sound.

[David Houck]

From a previous thread:
 
When you plug your input into channel A and your output is from channel B, you have, essentially, a 3 channel mixer. The three channels are parallel and are combined at the output.
 
Thus if one of the filters is set in high-pass mode, then it is limiting low frequencies only on that particular channel.  You can then set the other filter to boost low frequencies if you want.  The results are, as Mike said, summend together at the output.
 
The post mentioned above from the previous thread has a detailed example of how the low pass and high pass filters can be used together.

[David Houck]

It can all seem a bit confusing!

[2400wattman]

Hello Dave, how is it that you can get low mid punch w/ the two filters set at high & low pass?, and what freqs. are related to band pass? I have an F1-X but I would like more control over those low & high mid freqs. since the mid control virtually does nothing that satisfies me. I'm just a bit confused by it all.

[cosmic]

Thanks Dave. That is starting to make more sense to me. The key for my understanding was/is getting a grasp of the seperate channels mixing output. Now I can see how you really would not lose any frequencies so to speak.
 
I am going to have to get my hands on one of these things and play with it for awhile.

[David Houck]

Adam; as stated above, the SF-2 can be set up as sort of similar to a three channel mixer.  Your input signal is split into three channels.  So if one is the low pass filter and another is the high pass filter, then the third is the dry signal.  The only control for this third channel is a gain control; thus it's not really a mid control.  By adjusting the gain controls on all three channels relative to each other, more or less of the mid range can be emphasized.
 
On the F-1X, the bass, mid, and treble controls are interactive; thus you would use all three controls in order to shape your curve, rather than using the mid by itself.  For instance by turning the treble control you change the slope and midpoint of your mids.  So you could use all three controls to shape your curve for the mid range tone you want and then use the low and high pass filters of the SF-2 to smooth out the rest of the curve.  Go here, scroll down about halfway and read the stuff about the tone stack generator; then download the program, make the changes, and get a visual picture of how the F-1X tone controls work together.
 
The band pass filter would be another way to go.  On one of the filter channels, switch the mode to band pass.  On the frequency control, turn the knob anywhere between 45Hz and 6kHz to choose the frequency you want to pass through.  Then, use the damping ratio for the amount of boost to that frequency, and the gain control to mix it relative to the other signals.

[gare]

Howdy..prehaps this could help better understand the concepts of the filters better:
http://www.ethanwiner.com/filters.html
It's an explanation of filter theory..some of it's technical.
By using the low pass and high pass filters in tandem you can create notch filtering effects etc.
 
G