Advice wanted: FEA dual band compressor (DB CL)

[Nic.]

I was going to post this in the FEA fan club thread until I realised the last post was ages ago... well anyway.

I was thinking of getting both a crossover blend as well as a new compressor and I realised the FEA DB-CL might be what I need. However, before I actually order one, I figure I should ask if it's really what I'm looking for.

I have two main purposes in mind:

1) I want a multiband compressor so that I can keep a low drone going while tapping on higher notes. The low notes are around the first few frets of the E/A strings, higher notes around the 12th fret of the A/D strings. In theory it should work since the fundamental of these notes are on either side of the crossover range, right? Pretty sure this isn't an issue based on what I've read around here but just to be sure...

2) I use quite a bit of distortion on a fretless and try to balance the crunch with some mwah. Recently I had the idea that if I use a crossover, and only apply the distortion to the lows, then blend them back together, I could get some interesting results. I'm sure the compression on the highs will also help me to emphasize the mwah range a bit more too, thinking of a short attack on the distorted lows for initial attack and some bloom on the highs for the mwah to fade in.

Is it possible to use the FEA at the start of the chain, split the signal, run the lows into distortion, then recombine them using a Boss LS2? And my understanding is that if I do this, the uncompressed 5k+ frequencies will go to the "highs" output, right? Is there anything special that the compressor is doing when mixing the split signal back together within the pedal itself that I can't do with the LS2?

 

[scubaduba]

Paging @boomertech.

 

[boomertech]

Hi Nic, great questions!

1) I want a multiband compressor so that I can keep a low drone going while tapping on higher notes. The low notes are around the first few frets of the E/A strings, higher notes around the 12th fret of the A/D strings. In theory it should work since the fundamental of these notes are on either side of the crossover range, right? Pretty sure this isn't an issue based on what I've read around here but just to be sure...

Yes, the DB-CL will work nicely for that purpose. I would suggest that you use the limiter on the Low-Band side with a lower threshold setting to help sustain your drone notes.

2) I use quite a bit of distortion on a fretless and try to balance the crunch with some mwah. Recently I had the idea that if I use a crossover, and only apply the distortion to the lows, then blend them back together, I could get some interesting results. I'm sure the compression on the highs will also help me to emphasize the mwah range a bit more too, thinking of a short attack on the distorted lows for initial attack and some bloom on the highs for the mwah to fade in.

Is it possible to use the FEA at the start of the chain, split the signal, run the lows into distortion, then recombine them using a Boss LS2? And my understanding is that if I do this, the uncompressed 5k+ frequencies will go to the "highs" output, right? Is there anything special that the compressor is doing when mixing the split signal back together within the pedal itself that I can't do with the LS2?

I designed the DB-CL with separate low and high outputs just for that purpose. My use of the two outs was the opposite of yours... I put my dirt, delay, phaser and chorus on my high-band out. My goal was to keep my lows clean to keep from muddying up the sound of the band. One of my bands had a guitar player that would solo A LOT. Whenever he went into a solo the rhythm felt a bit empty, so by me adding a bit of my effects to just the higher frequencies and playing the root notes with their octaves filled in the empty space nicely.

When using the Low and High output jacks, the very high frequencies that were routed around the compressor circuits are recombined at unity gain with the compressed highs. So, they will be at the high output jack when both outputs are used.

The one thing that you must be aware of when mixing the two outputs is phasing issues. The internal 12dB/oct x-over rotates the signals by up to +90 degrees on the highs and -90 degrees on the lows. So, the two signals can be a total of 180 degrees apart at the crossover frequency if one of the phases is inverted. If the two outputs are mixed back together without any phase changes from external pedals, they will mix back together properly. If one of the output signals gets inverted by a pedal, then there will be a big, narrow notch of approx -30 to -40dB at the x-over frequency caused by the 180 degree difference in signals. Some distortions will sound really cool with this notch... so try it both ways (inverted and non-inverted). Because it is the frequencies nearest the x-over freq that are affected the most.

I hope that helped!

-Frank

 

[Nic.]

Hi @boomertech,

Wow that's a lot of detailed info! I totally forgot about the possibility of a phase shift.

"The internal 12dB/oct x-over rotates the signals by up to +90 degrees on the highs and -90 degrees on the lows. So, the two signals can be a total of 180 degrees apart at the crossover frequency if one of the phases is inverted. If the two outputs are mixed back together without any phase changes from external pedals, they will mix back together properly."

Sorry, slightly confused here... If the internal crossover performs a phase shift on the highs to bring it forward by +90 and pulls the lows backwards by -90, doesn't this mean that directly recombining the two outputs without any further changes (e.g. both outputs direct to a mixer) would have a phase diff of 180, and to solve this I should put in a pedal that flips the phase of one of them? Or do you mean that there's an internal phase shift, but the pedal will invert one of them before sending to the output so that the two outputs will be in phase, and it'll only be out of phase if I have a distortion pedal that inverts one of their phases?

 

[bongomania]

This sounds like an ideal case for the DB-CL.

 

[boomertech]

The phase is internally inverted on the high-band side so that if you directly take the high-out and low-out to a mixer you will be in-phase (no cancellation).

But if either the low or high output gets phase inverted by an external device, you will then have cancellation with that huge notch (if electronically mixing them together). If you run the high and low signals to different amps and cabs you will be acoustically mixing the signals, in that case, you may not experience/hear any issues with an external device that flips phase (when activated) that is connected to either the hi or low output.

-Frank

 

[Nic.]

@boomertech got it, thanks! That should probably be fine I think.