guitar signal data

[hogie]

Not sure if this is the right section to post in or if anyone on here can even help me out, so here goes nothing....

So I was thinking about trying to simulate guitar effects using Matlab. Does anyone have any guitar signal data that I could use or know how I could create my own dataset (ie: a link to a site with p-p voltage, frequency range, #harmonics)?

I don't have easy acess to an oscilloscope right now, otherwise I'd go measure myself.

[Old Tele man]

typical guitar pickup outout is about 10-100 mV at 8-100 Kohm impedance (Z), ie: remember:

Z = L (2-10 mH) of coil || R of VOL || RC of TONE || with C of cable cord

normal guitar frequency range (guitar, (piano), Hz):

E6 = (E2) = 82.407 Hz
A5 = (A2) = 110.00 Hz
D4 = (D2) = 146.83 Hz
G3 = (G3) = 196.00 Hz
B2 = (B3) = 246.94 Hz
E1 = (E4) = 329.63 Hz

E1' = (E5) = 659.26 Hz (fret 12)
E1" = (E6) = 1,318.5 Hz (fret 24)

you might find these helpful too:

http://wug.physics.uiuc.edu/courses/phys199pom/Student_Reports/Spring03/Amy_Trent/Amy_Trent_P199POM_Final_Paper.pdf

http://www.geofex.com/Article_Folders/impednc.htm

http://www.jensign.com/JavaScience/www/phoneaxe/phoneaxe.html

[hogie]

thanks! exactly what i was looking for.

has anyone here ever designed/simulated guitar effects using matlab or something else before?

[Old Tele man]

...did some stuff using Excel spreadsheet, but don't recall which diskette it was saved (?) on.

[Neon]

Hogie,

A guitar signal has a lot of harmonic content in it. So that low E, around 82.4Hz, will have plenty of energy at 82.4*n (n=1,2,3,.., ?). Of course, the harmonic content changes from string-to-string, fret-to-fret, etc. I'm sure you get the picture. Unfortunately, I don't have any specific examples of the harmonic content.

I have seen rudimentary spectrum analysis built into some audio editing software. This might help you get a better feel for the spectural content of the guitar signal. I know this isn't too specific, but it could get you started.

[Old Tele man]

...for 98% signal harmonic content accuracy, you need 50-harmonics!

...for 95% signal harmonic content accuracy, you need 20-harmonics!

...for 90% signal harmonic content accuracy, you need 10-harmonics!

Since most amps are frequency-limited by their SPEAKERS (5-6K Hz) and not by amp bandwidth (10-15 KHz), 10-harmonics are typically all you need.

For example, if you play the E1-string at 24th fret, the fundamental note is 1,318.5 Hz and 10-harmonics (not octaves) ABOVE that would be 13,285 Hz...or about TWICE the speakers capability. However, at the 12th-fret fundamental, the harmonics are down around 6,592.6 Hz, which is back into the "ragged" upper range limit of the speaker(s).

[TheAmpNerd]

Great Technical stuff you guys. : )

Can anyone answer this, I've kinda wondered about it.
Why are most guitar amps limited to 5-6k by the speaker
and typically don't have horns, tweaters, etc?

I know the harmonics and higher register stuff
are present in the guitar aren't they?

I recall reading about Steward Hegman when he was
designing amps and was going way beyond the
20 - 20,000 Hz because he said the research showed
that even though people can "hear" it, they sense the
higher frequencies typically chose speakers/amps
etc with much extended range beyon 20,000 Hz,
though they didn't know why.

Would it make sense therefore to build a guitar amp
that went to say 15,000 to 20,000 Hz, even though
the guitar doesn't go that high?

Anyone look into this?

I'm curious about this.

Now I'm going to go find a jam and play.

[Wakarusa]

Experiment for yourself. Jack your guitar directly into your stereo with the nice full-range speakers and full range pre-amp.

All the extra content doesn't (to my ears at least) sound very good.

[TheAmpNerd]

Originally posted by Wakarusa Amp
Experiment for yourself. Jack your guitar directly into your stereo with the nice full-range speakers and full range pre-amp.

All the extra content doesn't (to my ears at least) sound very good.

Trying, but I'll have to rig something to get a good
connection in that old 35w Marantz amp.

Let me open it up and see the best spot to mount a
1/4 jack....

There we go, right up front where it should be,
just off to the left of the center Marantz logo.

Too bad that amp is an ugly pink color, I'll cover it in
West Tejas Rattler.

This will be fun.

[Old Tele man]

...go to your local music store and listen to the sonic difference between a regular electric guitar amp and an electric-acoustic (piezo, etc.) amp!

The acoustic amps DO have wider bandwidth and use either piezo speakers or horns to "takeover" when the normal speaker(s) begin to "fade" (around 4-6KHz).

You can try connecting a piezo horn/speaker across your guitar amp speaker (use a 0.1uF coupling capacitor) to get some idea of what "sounds" you're NOT getting out of your amp because of the limitations of the speaker(s).

Reportedly, Bill Lawrence, the pickup builder, has a Deluxe Reverb with JBL and piezo speaker in his shop...it's purpose is to let him "hear" the harmonics and overtones that most amps chop off.

[glasman]

Originally posted by Old Tele man

The acoustic amps DO have wider bandwidth and use either piezo speakers or horns to "takeover" when the normal speaker(s) begin to "fade" (around 4-6KHz).


Take a look back in time on the use of Horns and guitar rigs.

Remember the VOX AC50's and AC100's (and the SS Super Beatle). Their matching cabinets all had horn tweeters mounted.

How about the old Acoustic series of guitar amps with the Horn on top of the two 15's.

Ahhh the good ol' days.

But in todays world most bass players (myself included) would not think of doing a gig without a minimum of a 2 way system(there are also 3 and 4 way cabinets for bass).

Back to building boards......
Gary

[fullerplast]

Originally posted by glasman
Take a look back in time on the use of Horns and guitar rigs.

Ahhh the good ol' days.



Recognize this rig? Six Wurlitzer horns!:eek: :D

http://img.photobucket.com/albums/v83/fullerplast/cipollinaamp.jpg

[glasman]

Originally posted by fullerplast
Recognize this rig? Six Wurlitzer horns!:eek: :D

http://img.photobucket.com/albums/v83/fullerplast/cipollinaamp.jpg


No, but a quick search revealed it definately belongs in the Rock and Roll hall of fame. Quicksilver was one of my favorite bands of that era!!

This way off thread.... Remember the Farfisa "Brasso" horn. Think it was Farfisa that built it.... and I think it was called the Brasso.

So many years and so many beers later......

Gary