Sound System Physics

shaferboy

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Hello all. I'm doing a Physics project on how a Sound System works electrically. I understand how an audio signal is transferred from a mic, how the volume is changed and how it is output through a speaker. I'm having an issue understanding how an audio signal is changed, from an electrical stand point, when it goes through an equalizer. If anyone can offer an explanation it would be greatly appreciated!
 
Hello all. I'm doing a Physics project on how a Sound System works electrically. I understand how an audio signal is transferred from a mic, how the volume is changed and how it is output through a speaker. I'm having an issue understanding how an audio signal is changed, from an electrical stand point, when it goes through an equalizer. If anyone can offer an explanation it would be greatly appreciated!

Since this is for a Physics Project perhaps some research is in order?


Now sorting though hits on Google on this I am sure would be daunting to say the least, and be not at all helpful. There are several books that explain this very well, but I am going to guess that how EQ works may be a little over your level right now. However with some research you can learn it.

Doing a Quick Google Search myself, there are lots of sites that talk about "how an EQ works" but NONE of them talk about how they actually work and the electronics behind them. However they are over the heads of most readers. Even the Yamaha Sound Reinforcement Handbook Second Edition as I recall does not talk about this (however does tell you how electrically and acoustically much works very well).

Assuming you have the nessasary electronics/electrical background and knowledge with a little work you could look at the diagram of an eq or console (eq on strip) and see the electrical components and see how they work.

I know I had some audio books that explained this but I think I lost them in the Tornado that ate my home and can't recall their titles.

Books and sources include:

READ THIS "Equalizers and Phase Shift" - An article I just found that does describe some of what is going on.

An instructable on making a 3 channel EQ - This will be great for you. Shows you a great simple EQ curcuit (3 Channels!)

Electronic Devices (Electron Flow Version) Eighth Edition - FLOYD, has an entire chapter (chapter 15) on "Filters" so includes "Low Pass Filters" "High Pass Filters" and "Band Stop Filters" among others. Not a cheap textbook ($200) but perhaps you can find a source for it? Library?

HERE is a PDF of the 9th edition I just found...

http://en.wikipedia.org/wiki/Equalization_(audio)
The Wikipedia article does talk about to some extent how EQ works electrically.

Wikipedia Article on "Electronic Filters" - another good start...


I hope this helps get you off to a good start. I'd also suggest talking with your physics teacher as he/she may be happy to help.
 
This answer is over simplified and not exact, but may help get you thinking.
Here goes......
Think of sound frequency like a rainbow, each frequency a different color. By increasing or decreasing creates different looks (sound). Too much of everything and you end up with a blur.
 
This answer is over simplified and not exact, but may help get you thinking.
Here goes......
Think of sound frequency like a rainbow, each frequency a different color. By increasing or decreasing creates different looks (sound). Too much of everything and you end up with a blur.

That's a halfway decent analogy for what amplitude shifting does in a GEQ, but doesn't even touch on Phase shifting! (It's a complicated answer that is really really hard to dumb down!)
 
That's a halfway decent analogy for what amplitude shifting does in a GEQ, but doesn't even touch on Phase shifting! (It's a complicated answer that is really really hard to dumb down!)

I agree completely. However both of you miss the mark completely on what the OP is asking. He's not asking WHY we use EQ or what EQ does or How to apply Eq... He's asking how EQ WORKS (electically). This is a completely different question entirely. However Phase shift is a big part of the answer.

Now we haven't seen the OP comment back, so I hope they've had a look and have continued to venture away on the project.

Please post with your progress (if any) I'd like to know how you've managed!

Hello all. I'm doing a Physics project on how a Sound System works electrically. I understand how an audio signal is transferred from a mic, how the volume is changed and how it is output through a speaker. I'm having an issue understanding how an audio signal is changed, from an electrical stand point, when it goes through an equalizer. If anyone can offer an explanation it would be greatly appreciated!

Remember that the microphone and speaker are both transducers. The electrical changes by the fader should be pretty self-explanitory if you are trying to understand how EQ works. Also remember that there is a world of difference between RESISTANCE and IMPEDANCE.
 
You are right, rereading it I see that. Sorry.
No need for apology, I just thought Id point it out. Furthermore I find it interesting how often people confuse "How does ??? Work" with "How does one utilize ???" (or such). As I said before when I goggled "how does EQ work", almost every hit did NOT talk about how it WORKS but how to USE it.

I guess I think in this day in age many of us really do take how things work for granted. Not that Im saying EVERY sound guy NEEDS to know electronics and exactly how everything works. But its true that a basic understanding about how things work and their principles helps you to understand how to effectively use it.

However this really is an alternate discussion perhaps for the "Off Topic" area, lol. But I have to say I am interested in where the OP is in the project.
 
I gave my presentation and primarily explained to the class how a mic picks up sound and transfers it to an electrical signal. I'm still a bit hazy on the EQ so I gave a very brief description. I then discussed how, in my understanding, a speaker does the opposite of a mic.
 

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