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Looper's Delight
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Should have read 'Resistance is how much opposition.....' Speaker impedance varies greatly with respect to the frequency of the signal. An 8 ohm speaker may have an impedance varying from 3 to 60 ohms (or more). Here are examples of speaker impedance across frequency: http://www.churchsoundcheck.com/imp1.html This impedance variation is one reason why low level active loudspeaker crossovers (as in bi amping) are preferred over high level passive loudspeaker crossovers (caps and coils at the speaker level). The varying impedance of the loudspeaker makes it difficult to design a high level passive crossover that interacts with the REAL impedance of the speaker (varies over frequency) rather than the IDEAL or STATED impedance (one value like 8 ohms). bret --- Bret <echoplex@yahoo.com> wrote: > Impedance is the oposition to AC or DC current (electron flow). > Impedance of a component will typically vary with frequency of the AC > signal. Impedance is a vector, consisting of 2 independant scalers - > resistance and reactance. > > Resistance how much opposition to the flow of electrons in either an > AC > or DC circuit or component. Lower resistance means LESS opposistion, > Higher resistance means MORE opposition (to the flow of electrons). > > Reactance is an expression of the storing or releasing of energy in a > circuit or component. Reactance occurs only for AC not DC. > Reactance > can be inductive (magnetic field storage/release) or capacitive > (electric field storage/release). Reactance is expressed in > imaginary > numbers. > bret > --- sine@zerocrossing.net wrote: > > Simply put, impedance is the interaction between resistance and > > frequency. > > It effects the signal transfer. I took a class where we looked at > it > > mathematically, and it was way beyond me. I think of impedance > > (load) like > > bike gears. A transistor is always trying to pedal with all it's > > might. If > > the gear is too low (2 ohms), the pedaling will be too fast > (current > > too > > high) and you'll burn your legs out. Most commercial amps like > the > > "gear" > > to be between 6-8 ohms. Two low and you can burn out your amp. > > Lot's of pro > > stuff will deal with a 2 ohm load. Touch your positive and > negative > > leads > > together to find out what will happen with no load. That smell > will > > be your > > amp frying. Your reactance will be one of crying and maybe > > shouting. If > > the impedance is too high, your amp probably won't care, but you > > won't get a > > lot of signal. > > > > This may be a horrible analogy, but it's how I think of it. Am I > > wrong? > > > > Mark Sottilaro > > > > MIKO wrote: > > > > > Can anyone put impedance and reactance into laymen's terms for me > > and tell > > > me what they impact? > > > > > __________________________________________________ > Do you Yahoo!? > New DSL Internet Access from SBC & Yahoo! > http://sbc.yahoo.com > __________________________________________________ Do you Yahoo!? New DSL Internet Access from SBC & Yahoo! http://sbc.yahoo.com