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Post by Yew on Feb 18, 2011 10:16:55 GMT -5
Ive just been thinking about single coil strats.
Here is an idea. a pedal with a high output single coil in it (maybe a p90), with a volume control, and a phase inverter? could this be used to take some of the hum away form single coils?
let me know if you think this would work?
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Post by ashcatlt on Feb 18, 2011 12:17:41 GMT -5
Let me ask you this:
If you turn your guitar, does the noise change? Does it change when you put it on the floor compared to holding it in playing position?
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Post by JohnH on Feb 18, 2011 15:36:56 GMT -5
Assignment 1: Ashs question, and a couple of minutes of further thought, will lead to an answer as to whether it is a good idea or not. Or is it better if such anti-hum provisions are fixed to the guitar?
cheers
J
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Post by sumgai on Feb 18, 2011 17:31:31 GMT -5
yew,
Assignment #2: Demonstrate how a metal box (presumably a standard stompbox) will not shield a pickup installed therein from any electromagnetic interference.
Show your work steps, complete with any math calculations and drawings necessary to support your conclusions.
Turn in your assignments no later than 5:00pm, Friday the 19th of February.
This is a pass/fail test, there will be no opportunities for extra credit.
Good luck!
Your professor at large,
sumgai
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Post by ashcatlt on Feb 18, 2011 18:25:35 GMT -5
Luckily, Friday 2/19 is 5 years away, so there's no rush.  |
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Post by sumgai on Feb 18, 2011 20:08:24 GMT -5
(private note to ash) ash, I thought to give yew time enough to graduate from his schooling, allegedly in Electrical Engineering, and then he can be fairly certain that he'll pass the test. I didn't wanna rush him or anything, ya know... might make for an embarassing mistake or something. (/end private note) |
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Post by ijustwannastrat on Feb 18, 2011 20:46:11 GMT -5
Hey, better than a plumber. They just need the $%@# to run downhill ;D
A teacher, an engineer, and a marine are in a drawn out argument about the economical status of the USA. Which one is correct?
None.
;D ;D ;D ;D ;D ;D
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Post by JFrankParnell on Feb 18, 2011 21:39:24 GMT -5
wait, I got an extra credit question: Explain why this hippie has two mics on his stand. Would that purpose be served if one mic was on the floor? :  |
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Post by ijustwannastrat on Feb 18, 2011 23:48:44 GMT -5
wait, I got an extra credit question: Explain why this hippie has two mics on his stand. Would that purpose be served if one mic was on the floor? : ... Are you suggesting the reason why some people use two mics is to cancel hum? I always thought it was because they were recording the performance, or something.... Also, EHX already has a hum debugger. You should see if you can get your hands on one, and reverse engineer it. Hum Debugger |
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Post by ashcatlt on Feb 19, 2011 2:08:39 GMT -5
Not hum, no.
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Post by Yew on Feb 19, 2011 8:18:51 GMT -5
First thoughts
For the mic's I always assumed it was either to have one for the stage Monitors and one for the audience.. different levels or something. maybe one for the vocallists mix, and one for the bands?
or maybe its to give a little bit of 'eq-ing' through the different microphone patterns? or even some distortion (listen to some old paul rodgers stuff)
The assignment.
HUm is caused by two things, echos of the big bang (think detuned TV) and 50/60 cycle alternation current in nearby devices, so if you put the pedal near an amplifier or something, you would have more hum, that you could cancel out using the volumne control
and the metal case problem is easy, use a plastic case like berhinger usually do.
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Post by Yew on Feb 19, 2011 8:29:59 GMT -5
pyrros, Truth to tell, even my rig can pickup hum, if the moon is full, the stars are lined up just right, and the witch doctor fails to dance in the correct direction around the campfire.  Which translates loosely to: within about 30cm of the amp head. Outside of that range, I'm more quiet than a mouse.  referance from sumagi, saying there is more hum near the amp |
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Post by asmith on Feb 19, 2011 11:17:34 GMT -5
Whoa, whoa, whoa, whoa, whoa, whoa, whoa, whoa, whoa, whoa, whoa, whoa. As a disclaimer, I'll say now that I'm sure that, technically, I'm the least qualified person here to comment about this. My education, whether formal, informal or self-applied, is undoubtedly outstripped by most if not all here. That said. Wasn't Yew's point that electromagnetic interference is supposed to be 'picked up,' so that one can invert the signal and cancel the hum from the single coil? Also, That was a little sneering. I realise ChrisK leaves a legacy of acerbic Master Po-ship here, but let's not push the Henry Jones Sr. into Gunnery Sergeant Hartman. When I first posted a thread full of layman-level questions here, and jumped blindly into what I thought was a 'eureka' moment, this was a very gladly received comment.Yew, whilst I get the gist from this thread that the idea wouldn't really work in principle, it's a lovely thought. Hell, Aristotle thought there were only five elements. Lois, this is not my Batman glass. |
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Post by ashcatlt on Feb 19, 2011 11:50:32 GMT -5
Oh, come on! It's all in fun. We're trying to get some thinking going on rather than just throwing out answers, but it's gone on a while and I guess... Wasn't Yew's point that electromagnetic interference is supposed to be 'picked up,' so that one can invert the signal and cancel the hum from the single coil? That is exactly sumgai's point! If it's in a metal box it won't pick up any noise and there won't be anything to cancel. I note that yew never actually said he'd put it in a metal box, and yes a plastic box would overcome this particular shortcoming. My point, and jfrank's, is that the noise on the floor ain't likely to be the same noise at the guitar. Hum cancelling the way we do in our guitars requires that the two coils be picking up noise which is very close to exactly the same. It works best when the two coils are as close as possible to the same in construction and also as close as possible to occupying the same physical space. The further apart they are, the less of the noise they're going to cancel. At a certain point, they will be adding more than subtracting, and the experiment will backfire. As to jfrank's deal: There are some folks who will have a second mic on stage for distortion or other effects. Sometimes, too, there might be a second mic for recording, but it's easy enough to split a microphone signal or take a tap off the board. I'm pretty sure the point is that this second mic is there, not being sung into, but relatively close to the actual sounding mic, and with it's signal inverted to cancel stage noise (bleed from amps and drums) and especially the sound of the PA/monitors/ambient field. This would allow more gain before feedback. The further apart those two mics are, the less likely they are to cancel. It might work with the mic on the floor, but only accidentally. |
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Post by asmith on Feb 19, 2011 12:29:52 GMT -5
Ah. There, I'm glad I put that disclaimer back there. I evidently read sumgai's "Demonstrate how [it] will not shield..." and settled into a comfortable assumption about what was meant, instead of thinking for my godforsaken self.
Also, thanks for the concrete explanation. I'd settled on that as what I figured the problem was, but as you can see, I'm prone to Acute Doofus Syndrome.
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Post by Yew on Feb 19, 2011 12:33:37 GMT -5
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Post by JFrankParnell on Feb 19, 2011 12:46:36 GMT -5
Oh, come on! It's all in fun. [...] I'm pretty sure the point is that this second mic is there, not being sung into, but relatively close to the actual sounding mic, and with it's signal inverted to cancel stage noise (bleed from amps and drums) and especially the sound of the PA/monitors/ambient field. This would allow more gain before feedback. The further apart those two mics are, the less likely they are to cancel. It might work with the mic on the floor, but only accidentally. Yes, the hippie in question is Jerry Garcia, during the Dead's Wall of Sound era. As you can see in the background of the pic, all the PA speakers were behind the band, allowing the band to hear themselves as the audience heard them. So, it was pretty frickin' loud on stage. The extra mic was inverted, therefore canceling out all but the singer. |
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Post by sumgai on Feb 19, 2011 13:16:00 GMT -5
Too bad I got so busy yesterday, and didn't check in like a good little boy..... Garcia.... Yes, a second mic is necessary for cancellation techniques. Splitting, inverting and remixing the signal from a single source just doesn't do the job, sorry to say. And for those who might not understand how this happens, might I suggest a quick foray down to your local Best Buy or some such, and give a listen to some "noise-cancelling" headphones. Not the "ear buds" type of earphones, but real honest-to-Gawd headphones. The have a mic built into each ear cup, and that signal is processed (inversion and filtration), then fed to the speaker - the result is that the sound from outside the headphone is cancelled by the sound coming out of the speaker. All that's left for you to hear is the music coming down the wire from your iPod or whatever. Needless to say, once you've tried this while mowing the lawn, you'll never go back to that greasy kid stuff!! Next.... A plastic stompbox? Really?  Gotta be cheap, 'cause it won't last long enough to make through the first encore..... And.... Ooh, I've been called a Chrisk-wannabe! Well, as we all heard the line in Machete - "If not me, then who". But I'll take that as a compliment, TYVM. ;D (Sorry if I channeled my previous life as a college instructor a little too graphically.) And finally.... yew, that single-P90 axe is the very antithesis of what The Nutzhouse is all about! But I also have to say that it looks to me like it'd be a very nice starting point for a whole ton of Nutziness! ;D HTH sumgai p.s. You all do realize that this is the only forum I habituate, right? Meaning, there's nothing to round off the sharp edges. (Well, The Real Boss might have something to say about that, but we won't tell him, now will we. ) |
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Which translates loosely to: within about 30cm of the amp head. Outside of that range, I'm more quiet than a mouse. 
Gotta be cheap, 'cause it won't last long enough to make through the first encore.....