hello, i recently joined this group after finding a post about noise rejection for guitars. I'm attempting to build a guitar equalizer, I have a fairly good idea of how to build the pass-band frequencies. What i want to include is a pre-amp that will reduce noise and hum. My question is what should i use for the pre-amp filter Averaging, gaussian of something else? Also what should my cut-off freguency be for the noise filter.
thanks ahead of time
~psu_EE

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maybe you could build a preamp that is geared to each string..
six preamps one for each pickup tuned to the particular strings frequency that would be cool..

 

not a bad idea but slightly unnessecary, having an equalizer accompolishes pretty much just that, what i was thinking of doing is having a dual equalizer, with a mono or stereo input, and a mono or stereo output, and an equalizer for the left & right channel.

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Keep in mind that a filter may not know the difference between noise and music. As I understand it, a given note from an instrument, is not a pure tone but a mix of tones, most of the tones being harmonically related to the fundamental note.

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stevez

 

Hi PSU_EE,
Why do your guitars have hum and noise? My microphones don't.
Is the noise from a poorly chosen noisy opamp and the hum from improper shielding? They can easily be corrected.

If you filter the hum and noise at the amplifier, you will also filter-out your signal.

 

hey audio guru, i live in an apartment with about 4 computers and a great deal more of gizmo's on at once, creates a good deal of interferance, shileding would most likly be the easiest thing to do so i'll probably end up doing that. I have a wireless system for my guitar also which cut down on a lot a of the noise, but i had to stop using it. Our neighbor nocked on our door and said he could hear the guitar coming through his channel 8, i turn off the emmitter and problem solved.

thanks for the advice then ~ psu_EE

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Hi PSU__EE,
I am glad that you decided to shield the interference, but frequently that is not good enough.
A shield on a cable blocks electrostatic interference very well, but electomagnetic interference poorly, because magnetism goes right thru the shield. You may need to use a mu-metal shielded transformer at both ends of your guitar's cable to balance the signal and allow the magnetic interference to be cancelled. Then your cable will be a shielded twisted pair.
Most good microphones have a balancing transformer inside and have 3 connections.

 

Hey PSU_EE,
sorry for the OT, but which campus are you at? I'm at Berhend in boring old Erie PA, going into my 3rd year for EE.

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Jeff
To the optimist, the glass is half full.
To the pessimist, the glass is half empty.
To the engineer, the glass is twice as big as it needs to be.

 

Everyone goes to PSU

 

I gotto the UP campus, :lol: yea everyone does go to psu

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http://sound.westhost.com/index.html

Lots of good information about amplification, pre-amp, EQ systems here. The "Articles" page has a LOT of info, and the projects page has some nice diagrams etc. One of my favorite audio sites.

 

sweet man, thanks a lot

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Do you play in a band or anything? I know a few guys who play at some places on college ave. etc. Or do you just play strictly as a hobby?

 

nope not in a band er anything, but playing is an excruciatingly close second to my girlfriend :lol: I play a lot of metal, and gothic type things, but i'd merily play Hot Rod Licoln, n' some Chuck Berry if the mood hits me. Having some other people to noodle around with would be fun.

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My 14 year old daughter plays bass and sings in a number of bands, she's done gigs and studio recordings - have a look at one of her bands web site at http://www.easilyamused.co.uk, there's even MP3's to listen to.

She also plays keyboards, guitar, flute and a bit of drums, but bass is her current passion - good guitarists are 'ten a penny', but good bassists are very rare creatures 8)

As a guitarist you really should try to get together with some friends and form a band - I'm presuming you're fairly young?, there may well be various music based schemes available to help you. It's good fun, and it will really help your playing improve.

However, we don't know where you are, if you entered your location in your profile it would be helpful.

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