Phasing with two pickups

[JimmyM]

Jonas Hellborg says his Warwick bass only has one pickup because two pickups causes phasing. Seen a lot of high end basses lately with only one pickup, I'm assuming for the same reason. A lot of killer bassists use two-pickup basses, though.

On all my PJ equipped basses, the P by itself on full is significantly louder than both pickups on full. The J pickup always sounds too thin for me to get a real bead on whether it's louder by itself, but it's very noticeable with the P. What causes that? Is it phasing?

What say you all about this issue? Do you hear it in your two-pickup basses? It's one of those things that I never once thought about until I read Hellborg's comments. I hear phasing with two pickups, but I thought it was because of the increased mid scooping inherent in the two pickup setup causing other instruments to drown it out. So what's the scoop?

[Slax]

My Ric does the same thing. Max volume on both pickups causes the bridge to be louder. For some reason rolling off the volume of the neck puts them back in phase and it sounds right.

I'm very curious of this thread myself. I seem to find myself mostly fiddling with one pick up most of the time.

[sonic assassin]

ric's have a circuit across the bridge pickup to make it thin and gross, so i dont think that counts.

my OLP sounds phasey and horrible with both sides of the pickup equal. ive always thought the same of jazz basses. take the bridge down a quarter turn and the bass opens up instantly.

[Slax]

Originally Posted by sonic assassin

ric's have a circuit across the bridge pickup to make it thin and gross, so i dont think that counts.

my OLP sounds phasey and horrible with both sides of the pickup equal. ive always thought the same of jazz basses. take the bridge down a quarter turn and the bass opens up instantly.

From you're post. It seems it does count. It's just the opposite. Why not just make them phase the same with both at full volume?

[sonic assassin]

Originally Posted by Slax

From you're post. It seems it does count. It's just the opposite. Why not just make them phase the same with both at full volume?

oh, i read that too fast, sorry. ive never heard of the bridge pickup being louder.

and im not sure i follow your question.

[T-Bird]

Hi.

When You pluck a string, you'll see that the cross sectional amplitude of the string motion of the fundamental is greatest in the middle of the string and smaller towards the nodes (string ends in the case of a fundamental). Since pickup sensing is rather narrow with a conventional single coil, the difference between the voltage created by the pickups can be quite significant. The two waveforms that have different amplitudes (obviously) may cancel out some frequencies and amplify others. Also the different order harmonics reproduced by the pickups may or may not be of the same amplitude, so the timbre created by the harmonics varies.

With humbuckers the phenomen isn't that pronounced as the sensing is wider in the first place, so the variance isn't that great as there's some shaping on both pickups even if not combined.

I wouldn't call the multi pickup tone bad, or problematic, it's just different.

Regards
Sam

[atheos]

Well, if we go technical ANY two sound sources that produce the same frequencies cause phasing. Mr. Hellborg is totally wrong to claim that phasing is something horrible that should be avoided at all costs (at least I get the impression that he's sort of "afraid" of the phasing). No, no and no.

There are three types of phasing: the good which improves your tone, the bad which makes your tone lack balls and the neutral which happens every time you have two sources producing the same signal but which you really don't even notice because it's natural part of audio physics and happens all the time. Having only one pickup eliminates the possibility of bad phasing but also the opportunity for good. It's up to the player to decide what he/she wants.

Jazz Bass is a great example, it's exactly the phasing that causes the mids to scoop when both pickups are equal volume. Some like it, some don't. It's just a matter of opinion really.

Phase knob (or just delay, say from 0 to 50ms) that affects only the other pickup would be kind of fun experiment. Requires a bit complicated electronics though so I guess I'm not getting one in a while

[sonic assassin]

i can agree with you in a lot of ways, atheos. sometimes we engineers will phase on purpose to make things sound good. thats what all that "keep moving the mic until it sounds good" bit is about. and its so much fun. i imagine that if it were in perfect phase, it wouldnt sound the same.

there was a situation where a royer 121 (thats bidirectional) was catching waves off of the wall behind it (20 ft away) and was phasing only certain notes. it was weird.. but if it were what i was going for, it wouldve sounded amazing.

personally a jazz bass full up on all knobs sounds a little muffled to me. i have to push it toward the neck to open it up a bit and retain the low end.

so yea.. those who throw the concept of audio phase around normally only understand the bad phasing.

[lunarpollen]

I wonder if wiring in series would help avoid such a thing...

[atheos]

Originally Posted by lunarpollen

I wonder if wiring in series would help avoid such a thing...

No, it wouldn't AFAIK.

[David1234]

Originally Posted by lunarpollen

I wonder if wiring in series would help avoid such a thing...

Not at all. If 2 signals are out of phase it doesn't matter whether you add them or average them, you still get zero.

[glamrockin]

Two passive pickups have different frequency response when wired together.

My favorite thing about a Rickenbacker is sending the sound of each pickup to a different pre-amp.

[glamrockin]

The neck pickup also has more ability to pull at the string as it rotates.

[slyjoe]

Originally Posted by David1234

Not at all. If 2 signals are out of phase it doesn't matter whether you add them or average them, you still get zero.

Correct David - but a small clarification for the lurkers here - they zero only if they are exactly 180 degrees out of phase.

"Out of phase" could be any amount of phase shift. Also, it is rather rare in the real world that the two signals are perfectly matched, which is required to zero out a 180 degree phase shifted signal.

Just sayin...

[Winemule]

Originally Posted by T-Bird

Hi.


I wouldn't call the multi pickup tone bad, or problematic, it's just different.

Regards
Sam

I don't doubt you for a moment; but I can also say with certainty that the day I turned off the bridge pickup on my Jazz was a great day.

[atheos]

Originally Posted by Winemule

I don't doubt you for a moment; but I can also say with certainty that the day I turned off the bridge pickup on my Jazz was a great day.

And I love the bridge PU as well as the scooped tone of both pickups - on the other hand the neck pickup alone sounds stupid IMO So here we are (again); it's just a matter of opinion. Same goes with original question, phasing is not a bad thing just because Hellborg doesn't like it. The world (and especially Internet, lol!) would be really dull place if there were only strict facts and no opinions to disagree with

[slyjoe]

Back to Jimmy's questions:

Originally Posted by JimmyM

Jonas Hellborg says his Warwick bass only has one pickup because two pickups causes phasing. Seen a lot of high end basses lately with only one pickup, I'm assuming for the same reason. A lot of killer bassists use two-pickup basses, though.

As noted previously, any two signals have a "phase" relationship. This may be good or bad or indifferent, and is a matter of opinion. No way around it.

On all my PJ equipped basses, the P by itself on full is significantly louder than both pickups on full. The J pickup always sounds too thin for me to get a real bead on whether it's louder by itself, but it's very noticeable with the P. What causes that? Is it phasing?

Actually, in passive basses, more than phasing is the pickup loading. When the J is off (grounded), you essentially only have the J pot in the circuit. As you turn up the J, the pickup loading from the J starts to affect the P more and more (and vice-versa).

What say you all about this issue? Do you hear it in your two-pickup basses? It's one of those things that I never once thought about until I read Hellborg's comments. I hear phasing with two pickups, but I thought it was because of the increased mid scooping inherent in the two pickup setup causing other instruments to drown it out. So what's the scoop?

I hear a difference in two pickup basses, but I don't believe this is primarily a phasing issue. Rather it is the pickup loading issue.

Ask the question - does this occur in active basses to the same degree? If so, you are talking about phasing. If not, it is due to loading.

Rewire one of the pickups out of phase with the other and you will notice a much different difference.

Hope this helps.

EDIT: When talking about active basses, you want to ensure the preamp is actually buffering the pickups before any mixing, as Audere does. Otherwise, you are back to the same problem of pickup loading. And the above little experiment won't yield the expected results.

[JimmyM]

Interesting discussion. What I'm getting out of it is "shut up and play yer bass," which is probably a healthy thing.

[glamrockin]

Originally Posted by slyjoe

Back to Jimmy's questions:

I hear a difference in two pickup basses, but I don't believe this is primarily a phasing issue. Rather it is the pickup loading issue.

+1

Originally Posted by slyjoe

Rewire one of the pickups out of phase with the other and you will notice a much different difference.

Out of polarity. I usually don't bother correcting this statement, but in this case I think it will add confusion.

[glamrockin]

Originally Posted by JimmyM

Interesting discussion. What I'm getting out of it is "shut up and play yer bass," which is probably a healthy thing.

Is that a Primus song?