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What's the main difference between running Time FX in the FX Loop or in chain???

Discussion in 'Effects [BG]' started by Terrorstorm, Mar 26, 2006.


  1. yeah... that's simply my question. maybe someone can make that clear for me? thanks:)
     
  2. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    By "time fx", do you mean time-based effects such as delay and flange? Or is there a specific "Time FX" unit that you're thinking of?
     
  3. yes, right! Delay, phasing, flanging .

    thanks
     
  4. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Generally speaking, there should be no problem using time-based fx either in series or in a loop. If your fx unit OR your loop has a "blend" knob, you may have to be careful with your settings in order not to get a muddy signal or phase cancellation. This is especially true with digital fx. As long as you've got the blends dialed in the best way for your setup, so the signal is not conflicting with itself, there is no problem using series or loop.
     
  5. Benjamin Strange

    Benjamin Strange Commercial User

    Dec 25, 2002
    New Orleans, LA
    Owner / Tech: Strange Guitarworks
    Sorry, but this isn't really true at all. Phase cancellation happens when you have two sound sources, not one. An FX loop is merely an insert in between your preamp and power amp (most times), and there is no need to worry about phase cancellation. Besides, most time based effects such as chorus, flanger, phaser, etc., are designed to create phase cancellation to some degree, by delaying a portion of your signal and then reintroducing it a moment later.

    The reason time based FX work in FX loops better generally is because when you put them in front of your preamp it can cause it to distort sometimes. Also, it's a matter of personal taste - do you want to chorus your bass sound before it's run through the preamp, or afterwards? For me, I use the preamp to create distortion, then run a delay in the loop. I find that I like to delay the distortion, not distort the delay. Delay can become a mushy mess if you're running it straight into the front end with some gain on the amp. However, most bassists play clean and have amps that have ridiculous amounts of clean headroom in the preamps, so this whole point may be moot anyway.
     
  6. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    When you run a signal through an fx loop with the blend on the loop at less than 100% AND the blend on the fx unit at less than 100% wet, you get some duplication of the original signal- two nearly identical sound sources. People make this mistake all the time. The loop is not "merely an insert" because of the blend knob.
    This is precisely why the blend-knob situation I described above can be a problem, especially with digital devices that may introduce small delays to the uneffected portion of the blended signal.
    But how is that different from any other effects? Name one way in which a time-based effect is different from a non-time-based effect when it comes to level matching.
     
  7. ah what the hell, I'll wade into this...

    Sorry, but it can be true! Some FX loops have a blend control, as bongomania pointed out. The upshot is that the clean signal can be blended with the signal from the FX return jack - these two signals can be unpleasantly out of phase at times; It's not a rule etched in stone as sometimes it just doesn't make a difference.

    Vanilla loops with no blend control don't have this problem, as you have pointed out.


    Personally, I don't like the sound of ANY effect through effects loops, and I've tried a lot of pedals in the loops.

    The major difference is that the effects loop comes after the preamp. I think it has little to do with the potential for distortion as Ben mentioned, and more to do with the tone shaping and signal amplification that takes place in the preamp stage. What the pedal gets is already different to the straight instrument signal, and what it sends back to the amp is not processed in the same way as if it was connected right at the input to the preamp.

    Some FX loops are high pass filtered which is fine for bottom sucking pedals like guitar distotions, but wreaks havoc with envelope triggered effects like auto wahs etc.

    Ultimately it all (like everything else in the universe) comes down to personal taste. Suck it and see and don't let anyone tell you you're doing it the stupid way!
     
  8. Benjamin Strange

    Benjamin Strange Commercial User

    Dec 25, 2002
    New Orleans, LA
    Owner / Tech: Strange Guitarworks
    I was speaking of plain old FX loops without a blend, but I agree it can happen with parallel loops. But when you are running FX, it is generally not two identical sound sources. They are different, due to the effected sound. Now, if the FX were in bypass, and if the loop isn't being run at 100%, I imagine that some slight phasing could occur. In a technical sense, *some* phasing *could* happen if these factors are in place - but it's going to be extremely slight and I doubt that most people would notice. Phasing happens ALL the time in sound; cabinet placement, room acoustics, ears being 6 inches apart... I think it's splitting hairs when in reference to FX loops. I will concede that you are technically correct, but I don't think phasing is the main point of the original question. However most companies worth their salt are phase aligned with themselves, so it's probably pretty rare that this would be a major problem.

    I'm not talking level matching here, I'm talking tone. Chorus pedals especially are known for bumping the midrange a bit, causing a preamp to disort differently than what is expected. Delays start stacking up, also causing the front end of an amp to distort - which is fine if you're into that sort of thing. It does boil down to taste. Hendrix ran his stuff straight into the front end of his amp, and it sounded fine.

    For the record, I've got a bajillion FX, and I've tried just about every possible combination. I find that time based FX generally run better in the loop, but do what sounds best to you.
     
  9. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    For the record, so do I, and so have I. I have run into phase cancellation problems many times under the circumstances I described (one recent example being a D.A. Green Ringer clone, the output of which includes the original signal, with no blend knob). So it IME is not some rarified potential freak circumstance, but a common problem easily remedied.

    The bits you mention about chorus bumping the midrange, and delays stacking up... those are level-setting issues, not tone issues. And it seems to me it's not a question of "hey, whatever sounds good to you" so much as a question of "are the levels set so as to avoid (or encourage) distortion?" Sometimes compression is needed to even out the peaks and valleys. And it seems to me that the exact same thing holds true for envelope filters, fuzzes, and any other non-BBD effect.
     
  10. Benjamin Strange

    Benjamin Strange Commercial User

    Dec 25, 2002
    New Orleans, LA
    Owner / Tech: Strange Guitarworks
    Ah. Perhaps I don't run into it as much as you is because my FX loop is series, not parallel. I haven't experienced any phase issues due to that.

    As for stuff hitting the amp first, it isn't really a level setting issue - having a midrangy bass, for instance, is not something that can be completely eliminated by setting levels and tweaking midrange knobs. Sure, some parts can be made to seem less evident, but the tonal character of the bass still comes through. Same with delays and chorus - having a chorused sound or delayed sound hitting a preamp tube will not sound the same as having a tube driven sound being chorused or delayed, no matter how many knobs are turned.
     
  11. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
    Fair enough. If anything, our debate should demonstrate to the OP that the only way to "clear it up" is to try both ways and see what sounds right to him. :)

    P.S. I really enjoyed "Lamentations of the Widow".
     

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