Why do Phase pedals "suck bass"?

[ohmelter]

Hello. What causes many phase pedals to make the bass mushy or saggy sounding? By many I mean some of most popular..MXR, EH, etc. What can be done to prevent this in circuit? For example, in the Phase 90.

Anthony

[jkokura]

That's such a subjective question I'm not sure that it's that simple to answer. Every pedal might give you that same result by in a broad variety of ways to be honest. I actually find that the Phase 90 I used to own didn't do what you're implying it does, suck bass. In fact, I found it sucked my treble out. However, with a little bit of EQ on my amp I found a happy medium in my tone that was equal with the pedal on and the pedal off.

I think that even well designed circuits can sound like crap with a poor guitar, terrible quality cables that are really long, and/or a bad amp too, so with all due respect, Are you sure it's the pedal?

Jacob

[daverdave]

Basically phase shifters produce a filter response that will reduce certain frequencies in the signal due to the cancellation produced by mixing the phase shifted signal and dry signal. I've never tried a phase 90 but I used to own a small stone, that had a bit of a volume drop, which is what you might be experiencing. I found that with the volume drop and the sound of the effect made the signal sound bassy and compressed. One idea might be to just try and boost the output of the pedal in question. Shouldn't be too difficult as both use buffers and summing amps that you could tweak to provide some gain.

[Eb7+9]

Hello. What causes many phase pedals to make the bass mushy or saggy sounding? By many I mean some of most popular..MXR, EH, etc. What can be done to prevent this in circuit? For example, in the Phase 90.

Anthony

the Bias control in jFET phasors sets the mean (average) point in the sweep ... the width of the sweep sets the resistance limits of the jFETs and so the frequency limits of the phasor stages as well ... you can move the range of the response up so it doesn't affect (cancel) the bottom end as much by varying the Bias adjustment slightly ... alternatively you could use smaller phasor caps to shift everything up in frequency

[Mark Hammer]

A lot of modulation pedals a not perfectly suited to bass if they permit the effect produced to extend over the full spectrum.  Personally, I find that reducing the value of any cap in series with the wet signal, at the point where wet and dry get mixed, helps to keep the bass solid like it needs to be, and makes the effect more nuanced.  So, for flangers and choruses, I reduce the value of that cap such that the wet signal starts to get rolled off below around 300-400hz.  Same thing can likely be applied to a phaser.

This in addition to what JC/Eb7+9  suggests.  Two ways to reach the same point: you can either move the sweep upwards so that it leaves the bass notes largely untouched and only filters the harmonic content, or you can reduce the intensity of the effect when it sweeps down into that region where it might rob you of some of the meat of the bass.

[alex frias]

Good point!!!

So anybody knows wich phaser Mr Tony Levin used to have in his pedalboard over the years? I love the sound of a Chapman Stick with it...

[ohmelter]

Wow..what great info, one and all!
I'm going to try the cap adjustment thing. Maybe I can get at more of a compromise between bass and effect response for my own personal taste. So if the caps in the filter section are .047, maybe I should try .02? Thanks for all the great tips.

Anthony

[Mark Hammer]

Just for the hell of it, replace the 150k resistor that mixes in the phase-shifted signal in the P90 with a 4700pf cap in series with the 150k resistor.  That should introduce a bass rolloff of the phase-shifted portion, starting around 225hz.