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12-25-2008, 09:22 PM
| | | | How to block magnetic field from pickups?
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Ok, I had a thread a while back where I was trying to get information about external pickups because I was trying something and I didn't to tell anyboidy about it. It can be found here for those who care External pickups
It isn't really relevant but whatever.
I'll divulge my secret, only because I cannot acomplish it. I'm trying to block half of one pickup and half of another so that I can send thhe signal of one pickup to one output, covering the top 4 strings, while I have the other pickup sent to a seperate output covering the bottom 2 strings (I have a 6 string bass). This way I can have 2 outputs to apply different effects to different sets of strings. The only problem is how to block the magnetic field? I bought some EMF shielding foil but it didn't work at all, so that was 40$ down the drain.
One solution of course is to router holes for some p bass pickups, but I'd rather not take a router to the bass, or pay someone else a huge sum of money to do it. It's my last resort. Does anybody have any ideas on how it might be possible to block off the magnetic signal between the strings and pickups? |
12-25-2008, 09:32 PM
| | Registered User | | Join Date: Jan 2008 Location: near Ft. Worth, TX, U.S.A. | | | You cannot accomplish this without separate coils. This means separate conductors (metal wire) carrying those two different musical signals to the two different output jacks.
Magnetic field blocking has nothing to do with it. As an aside though, if you blocked all external magnetic fields from the pickup, then the pickup wouldn't actually "pick up" any signal from the strings!
No matter what pickup rout you have now, here's what you do: Get a split-coil humbucker with 4-conductor wiring and you can achieve what you're trying to do. Wire up each of those two coils to a separate output. You'll have the top strings and bottom strings producing separate signals. Voila! |
12-25-2008, 09:47 PM
|  | Registered Bass Offender | | Join Date: Nov 2007 Location: Cambria, CA (Central Coast) | | | +1
FYI, shielding magnetic fields is very difficult. It isn't something that can be easily accomplished.
As for your idea being secret, I'm sure people have experimented with split high/low pickups over the past 56 years of electric bass.
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12-25-2008, 10:03 PM
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Originally Posted by 4StringTheorist  You cannot accomplish this without separate coils. This means separate conductors (metal wire) carrying those two different musical signals to the two different output jacks.
Magnetic field blocking has nothing to do with it. As an aside though, if you blocked all external magnetic fields from the pickup, then the pickup wouldn't actually "pick up" any signal from the strings!
No matter what pickup rout you have now, here's what you do: Get a split-coil humbucker with 4-conductor wiring and you can achieve what you're trying to do. Wire up each of those two coils to a separate output. You'll have the top strings and bottom strings producing separate signals. Voila! | The problem with that is that I would have coverage of 3 and 3 instead of the top 4 and bottom 2. The reason I wanted sheilding was so I could change which string I wanted on the outputs. Sometime if I ever want the top 2 and bottom 4 I would just be able to slide the sheilding over but I guess that's unrealistic.
I even got this idea of mounting pickups onto a utility knife tool (minus the blade) so I could slide the pickups up and down but soon realised how big of a pain it was to achieve. I have thought of that solution, (at least my dad did. He's good with electronics), but like I said it gives me a 3-3 coverage. I have 2 songs where I want 4-2 coverage, so I need something for that. My bass has soapbars so I would have to router it for the effect I want. Quote:
Originally Posted by Rick Auricchio +1
FYI, shielding magnetic fields is very difficult. It isn't something that can be easily accomplished.
As for your idea being secret, I'm sure people have experimented with split high/low pickups over the past 56 years of electric bass. | It has been done before. I didn't even think of the idea myself. I got it from a bassist named Jean baudin, but I never heard it implemented. I was playing around and thought to myself "man it would be badass if I could do that!" then the gears started turning and now I'm frustrated because I can't do it.
Thank you both for your replies!
Another thing I thought of was to get tiny guitar pickups like this one http://cgi.ebay.com/ws/eBayISAPI.dll...m=140287061435 , but I'm not sure how well guitar pickups would function on bass.
Last edited by thagreatbelow : 12-25-2008 at 10:17 PM.
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12-25-2008, 10:18 PM
| | Registered User | | Join Date: Jun 2008 Location: Back in MI | | Completely off topic but... TheGreatBelow, is your name a direct reference to the NIN song The Great Below? 
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12-25-2008, 10:23 PM
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Originally Posted by BryanSwift Completely off topic but... TheGreatBelow, is your name a direct reference to the NIN song The Great Below? | Yes! I love that song  |
12-25-2008, 10:27 PM
| | Registered Bass Offender | | Join Date: Nov 2007 Location: Cambria, CA (Central Coast) | | | If you really need pickups to cover different strings, your best bet is a custom instrument. You can use a few short pickups or piezo bridge saddles.
As far as moving pickups around while playing, I think that's fraught with problems. You'd have some noise as you moved them, plus a thump as they moved under the strings.
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12-25-2008, 10:30 PM
| | Registered User | | Join Date: Jan 2008 Location: near Ft. Worth, TX, U.S.A. | | Quote:
Originally Posted by thagreatbelow The problem with that is that I would have coverage of 3 and 3 instead of the top 4 and bottom 2. The reason I wanted sheilding was so I could change which string I wanted on the outputs. Sometime if I ever want the top 2 and bottom 4 I would just be able to slide the sheilding over but I guess that's unrealistic.
I even got this idea of mounting pickups onto a utility knife tool (minus the blade) so I could slide the pickups up and down but soon realised how big of a pain it was to achieve. I have thought of that solution, (at least my dad did. He's good with electronics), but like I said it gives me a 3-3 coverage. I have 2 songs where I want 4-2 coverage, so I need something for that. My bass has soapbars so I would have to router it for the effect I want. | If you're okay with two separate pickups feeding your two different signals, then try some iron bars as a shield. The only easy way you can block a magnetic field is with a material with a magnetic moment. (iron, nickel and chromium in normal conditions)
The trick is keeping the magnets in your pickups from magnetizing the iron "shield". Even then, the material might not do enough shileding to block your musical signal from the strings whatsoever.
Can't hurt to try though! |
12-25-2008, 10:52 PM
|  | Registered User | | Join Date: May 2006 Location: Buffalo, NY | | | Seperate outputs...
Why not just get the Roland pickup? That will give you each string seperate - your could run them all into a 4-6 channel mixer (depending on how many strings on the bass you are using) and then choose which strings go to which FX- even automate the mix if if needed. |
12-25-2008, 10:55 PM
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Originally Posted by ric stave Why not just get the Roland pickup? That will give you each string seperate - your could run them all into a 4-6 channel mixer (depending on how many strings on the bass you are using) and then choose which strings go to which FX- even automate the mix if if needed. | I don't think that's how the roland pickup works. You need some sort of proprietary roland device to play synths with. It doesn't even pick up analog string sounds (or so i believe. I could be wrong) |
12-25-2008, 10:57 PM
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Originally Posted by 4StringTheorist If you're okay with two separate pickups feeding your two different signals, then try some iron bars as a shield. The only easy way you can block a magnetic field is with a material with a magnetic moment. (iron, nickel and chromium in normal conditions)
The trick is keeping the magnets in your pickups from magnetizing the iron "shield". Even then, the material might not do enough shileding to block your musical signal from the strings whatsoever.
Can't hurt to try though! | That could work, but the clearance between the strings is like 1/8 of an inch and with iron in between that doesn't leave much room to vibrate. It's a good idea, but I already tried the foil so I'm spoiled on that idea. |
12-25-2008, 11:06 PM
|  | I Know Nothing | | Join Date: Dec 2003 Location: Columbia River Gorge, WA. | | Quote:
Originally Posted by thagreatbelow I don't think that's how the roland pickup works. You need some sort of proprietary roland device to play synths with. It doesn't even pick up analog string sounds (or so i believe. I could be wrong) | You are wrong, the Roland pickup is magnetic and outputs analog signals, and you don't need a synth per se. The V-Bass will do what you want very well, but you can also break out the individual signals into your own interface given enough time and money. |
12-25-2008, 11:09 PM
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Originally Posted by Passinwind You are wrong, the Roland pickup is magnetic and outputs analog signals, and you don't need a synth per se. The V-Bass will do what you want very well, but you can also break out the individual signals into your own interface given enough time and money. | How exactly would that be possible? I'm VERY curious how it works then! |
12-25-2008, 11:23 PM
| | I Know Nothing | | Join Date: Dec 2003 Location: Columbia River Gorge, WA. | | Quote:
Originally Posted by thagreatbelow How exactly would that be possible? I'm VERY curious how it works then! | Paging greenboy...or the rest of the V-Bass crew. 
Very briefly, the pickup has six individual coils and feeds a 13 pin connector. You build a breakout box and assign strings wherever you please in the breakout box. There would be two mixing sections, and perhaps ideally individual EQ per string. The pickup is very close to the bridge ans I'm not sure exactly what other processing some into play to beef the sound up sufficiently. At this point, buying a used V-Bass is already starting to look quite attractive IMHO.
There may be some other ready commercial solutions at this point, but my VG-8 playing days are way behind me and I haven't really kept up. But I did have the Roland 1:2 breakout box myself at one time, and judging from what I saw inside it, doing what I described is not super-difficult if you have good electronics chops.
Last edited by Passinwind : 12-25-2008 at 11:57 PM.
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12-25-2008, 11:45 PM
| | | | I don't have the elctronics chops, but it doesn't sound too complicated if that 13 pin connector I would be able to feed into anything I wanted. But that raises another issue. Those are built for guitars, but I'm using a 6 string bass. I don't think the magnets would align with my strings. |
12-25-2008, 11:51 PM
|  | I took the one less traveled by | | Join Date: Mar 2002 Location: Reims, Champagne, France | | | Roland and Yamaha both make hex bass pickups with 13-pin output.
Splitting string signals from a single bass has been done many,many times in history.
Last edited by Jazz Ad : 12-25-2008 at 11:56 PM.
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12-26-2008, 12:05 AM
| | | | What exactly do you do with a 13 pin output? |
12-26-2008, 12:16 AM
| | I took the one less traveled by | | Join Date: Mar 2002 Location: Reims, Champagne, France | | | I have no idea. It just became the de-facto standard for this kind of pickup since Boss started using it back in the late 80s.
They're used to carry a lot of information such as channel change, volume, digital info and analogic signal for each string.
You will need to look around a bit to get the info. |
12-26-2008, 12:19 AM
| | I Know Nothing | | Join Date: Dec 2003 Location: Columbia River Gorge, WA. | | Quote:
Originally Posted by Jazz Ad I have no idea. It just became the de-facto standard for this kind of pickup since Boss started using it back in the late 80s.
They're used to carry a lot of information such as channel change, volume, digital info and analogic signal for each string.
You will need to look around a bit to get the info. | The GK-2 pinout is here, for starters. There is a whole community of hackers for the VG and VB units, a little searching will net a lot of info IME. | | Thread Tools | Search this Thread | | | | 
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