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Hi!

Good friend of mine running his bass into 3 big tube amps. However the trick is to have all 3 ones in phase to avoid phase cancelations.

Usually he using Lehle P-Split spliters. But then he found this article where Gentry Denslay talking about custom made pedal dedicated to align 3 amps in phase in way like Little Labs IPB phase alignment tool working. ( http://thequietus.com/articles/02959-eagle-twin-interview-the-unkindne%20ss-of-crows )
You could ever seen one on Boris's Wata pedal board http://ilovefuzz.com/viewtopic.php?f=137&t=7539&p=192546#p192546

Does anybody knows how to DIY this pedal? Is it difficult?

All ideas are welcome

if there being micd theres a formula that u can use to work out the cancellation with panning

tuffteef wrote:if there being micd theres a formula that u can use to work out the cancellation with panning

what kind of formula is it?
it could be solution for FOH, but not for stage sound.

ural wrote:

tuffteef wrote:if there being micd theres a formula that u can use to work out the cancellation with panning

what kind of formula is it?
it could be solution for FOH, but not for stage sound.

i don't know this particular formula but the formula for recording mic placement is 2:1. That is to say that if you place one mic one foot away from the source, you want the next mic 2x the distance from the first mic to avoid phase cancellation.

Might be a good place to start when trying to figure this out.

elbandito wrote:

ural wrote:

tuffteef wrote:if there being micd theres a formula that u can use to work out the cancellation with panning

what kind of formula is it?
it could be solution for FOH, but not for stage sound.

i don't know this particular formula but the formula for recording mic placement is 2:1. That is to say that if you place one mic one foot away from the source, you want the next mic 2x the distance from the first mic to avoid phase cancellation.

Might be a good place to start when trying to figure this out.

Thanks! Yes, I know this formula.
My question was more about sound of amps and cabs as such not so much about recording. I have Hiwatt 400 and pair of Orange AD 200 running triple 8x10 Orange cabs. It's very strong setup with impact on over all sound not just stage . I'm using pair of Lehle P-Split to keep those amps in phase. But Lehle have simple phase switch, while this "phase waver" possibly behaves like Little Labs IPB - with this you probably can adjust degree of phase. If yes, it probably makes also different color of sound - when signals are not exactly in phase.
This is why I'm looking for advice what this "phase waver" is and what it does.

I think you should use a phase shifter, like in phasers, but only one, and without driving the resistor (in phasers it's a FET or LDR) with an LFO. Just put a pot in it, and you should be able to adjust the phase. You'll need max. [number of amps]-1 out of that, one for each splitted signal. So in your case one signal splitter+2 phase shifter.
In P-Split (or in similar devices) that switch flips the phase (90°). Instead of that you can - maybe - simply flip the polarity of your speaker cables (not all of them!).

YYC155 wrote:I think you should use a phase shifter, like in phasers, but only one, and without driving the resistor (in phasers it's a FET or LDR) with an LFO. Just put a pot in it, and you should be able to adjust the phase. You'll need max. [number of amps]-1 out of that, one for each splitted signal. So in your case one signal splitter+2 phase shifter.
In P-Split (or in similar devices) that switch flips the phase (90°). Instead of that you can - maybe - simply flip the polarity of your speaker cables (not all of them!).

thank you YYC155! i think your suggestion can be solution. Maybe I could use 2 P-Splits in combination with 2 phase shifter pedals modifed as you told, isn't.
However I have not lot of experience with phasers. Who of them could be most suitable for bass and for this kind of mods?

elbandito wrote:

ural wrote:

tuffteef wrote:if there being micd theres a formula that u can use to work out the cancellation with panning

what kind of formula is it?
it could be solution for FOH, but not for stage sound.

i don't know this particular formula but the formula for recording mic placement is 2:1. That is to say that if you place one mic one foot away from the source, you want the next mic 2x the distance from the first mic to avoid phase cancellation.

Might be a good place to start when trying to figure this out.

my boss has done live sound for 30 years and I have been in recording for a minute so I can say with 100% certainty that this is wrong. the wavelength changes with the frequency so I can use a formula to figure out what note on the bass will be 100% silent when the signals from both mics are mixed down to equal volume. the only way to prevent phase issues 100% of the time when using more than one mic on one source is to have the mics perfectly parallel with the diaphrams (not the bodies!) placed at the same exact distance from the cone (not the center of a 4x12). when you start placing 3 amps in a room, you will ALWAYS have focus points. most sound guys set it up so that the focus is center stage front row. all the cabs are in a ring and it makes perfect round waves throughout the stadium. best thing for you if you have 3 amps is use two and have a phase reverse switch on one of them. or take the smallest one and put it next to your head. the other two should be lined up in an x at 30 degrees or so. so it makes the focus at center stage, on stage. you'll be standing in the dead spot off to the side but you'll have an amp less than one foot from your ear to use as a monitor. some guys just use the monitor amp as a preamp and run lineout to a board or other amps. you can also put your monitor amp so its almost in its back. you gotta make two rubber feet or something.

to find the correct setting for phase, stand in the sweet spot of the x and play. you 3rd amp should be off for this test. do a A/B test with the phase switch on only one of the amps. while standing in the middle and jamming. wherever it is loudest is the proper setting. 3rd amp doesn't matter cause its pointing up and its also not that loud.