I still confused abut impedance high is 8 ohms and is low is 4 ohm? help!

Audio Components Amplifiers
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Yes, speakers do the most damage to the signal PHASE as they have lots of inductors in the X-over and voice coils that change PHASE.

The musical signal itself is rather complex, too. At any given moment there is but ONE voltage at the loudspeaker terminals. This one voltage is the superposition of ALL the musical signals added into ONE single voltage with a specific PHASE angle derived from all the phase angles associated with every signal “added” together. So we introduce PHASE even at the earliest stages of the signal.

It is like your checkbook, the very LAST number is what matters, and is the “superposition” of all the other account variables added. Capacitance and inductance would be the payments and deposits that aren’t here yet. They are shifting the TIME value of the account some. Like your checkbook, using calculus, you COULD deconstruct all of what was in the final signal, however.

A really good question is if it is just ONE voltage, and the current amount determines the wattage we listen to, why do we HEAR so many signals at once? The best I can say is like the checkbook example, we hear ALL the register entries over TIME such that it represents the final total of signal. A SQUARE wave is a whole bunch of sine waves compiled over TIME. If we add reactance to those sine waves, we see DISTORTION in the square wave. This is way easier to see than in a musical signal that is a mess over time so many testers use square wave responses to get an idea how an amplifier does, or even a speaker (step responses on time-aligned speakers).

I chose to limit INDUCTANCE in my cable products because it effects PHASE in the audio band. Capacitors aren’t bad until you reach the Fc –3 dB and 45 degree PHASE frequency (in the MHz range) and as capacitors act the OPPOSITE of inductors, they change the high frequencies where inductors change the audio band frequencies. Given the choice, and there is one, I chose to keep inductance LOW, but still hold capacitance as low as I can while doing that. This helps PHASE stay as low as we can in our systems.

Amplifier stability kind of goes in a BIG circle to the entire chain. Cable’s aren’t magic, and another good source is https://www.qed.co.uk/cablesmatter for accurate REAL measurements that cables exhibit. I like sites that provide a more meaningful user experience. All electronics are a balancing act because of REACTANCE.

Best,
Galen Gareis

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22

There is not a zero OHM circuit, though. I=E/R so if R keeps getting lower, yes, CURRENT keeps going UP based on “R” and the amp WILL blow up if R is too low. This is why low impedance speakers are a bear to drive and worse, if they have reactance on top of it. Reactance steals away the vector magnitude of the RESISTIVE vector, making it “smaller” or shorter in the vector math. This make the current go UP even more.

Here we see the standard POWER cheat sheet. Notice that the “apparent” power is the LONGER vector, or hypotenuse. But, we can’t use all that as it is REACTIVE, so we see that ONLY the bottom vector, the ACTIVE power is used. This is weird, I know but I don’t make this up, I’m not able to be this weird. If we applied ALL reactive power to a motor, it would NOT MOVE! Only when it is REAL vector can it do WORK. Notice the ACTIVE POWER is also called I*R, or watts. But, is is REDUCED by the COS of the Apparent Power we can’t use yet. This is what’s happening in our speaker and amplifier.

image

Nothing is free and we trade currency for voltage and voltage for current in an amp. The watts remains the same as it is a multiplicand of the amps x volts.

Best,
Galen Gareis

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23

This has long fascinated me. A full symphony orchestra in all its complexity rendered down into a single voltage. Yes it changes with time, but this makes it even more magical.

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Yep… amazing… I get that all sound sources are summed to a single air pressure value as it moves your ear drum (as in electrical circuits)… but how our brains can sort it out… wow, that is the big one for me. To be at a crowded party… look at someone across the room, and with just a bit of focus using sound and maybe their mouth movements, your brain can hear them speak. Cripes is that amazing.

Peace
Bruce in Philly

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It is astounding.

Another example is being at a concert with an orchestra at full tilt, looking at the flute player, and being able to tease out the flute part.

At least for me, what I see greatly influences what I hear.

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Hearing electrically amplified instruments, speakers moving the air to make the sound, playing outside, a block away, around the corner and knowing by the sound that it’s live.

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Looking back, I always do. The TWO post I’ve made cam be CONDENSED into ONE with even better conveyance of the answer. Being a teacher once, you sort of review in your head what you’ve said, and if it is “efficient”. This isn’t easy to do. I suggest I’m a piece of lead mentally that is lifted by the fisherman’s line off the bottom. The closer I get to the surface the smarter I think I am but…those student who do the lifting by asking the questions move on to be far smarter than I am. When they move on or I change subjects, I’m sunk again.

If we look at a given load in an instant in time and frequency, the above curve of a typical ported speaker shows what to expect, we capture that LOAD value.

Let’s say it is 16-ohms. The amp/cable/speaker is a voltage DIVIDER rule network. The VOLTAGE that is dropped across the LOAD is proportional the the loads resistance. We would like a load of infinity as ALL the voltage would be at the end of the infinite load but, the current needed to do work is zip. OOPS.
OK, so we can’t use ZERO ohms. we need something higher than that to do WORK which requires AMPS (current) times volts.

The HIGHER the speaker impedance, the more voltage is dropped across that load for a given current so we see better WATTS with less amps. We hear WATTS, and this is why tube amps like high impedance speakers. Tubes do voltage well, not so much current. SS do current better but that’s just better, not perfect.

Let’s throw in REACTANCE. As I said earlier, reactance diminishes the magnitude of the REAL or resistive part of the vector magnitude so a high reactance at and given impedance will LOWER the REAL component and DECREASE the VOLTAGE across that load. We want MORE voltage, not less. This is why a low impedance load with reactance is a bad thing, it is making a low impedance even LOWER restively. We can lower 16 ohms some and be OK, not so much 2 ohms!

The current is the SAME through a series circuit. Voltage divides up based on the load’s resistances through the circuit. The higher resistance at a load is, the more volts it gets and the higher the “work” we get at that load with the constant series current. Where we want to do the work should be the higher “impedance” as watts = amps times volts.

What gets real messy, is that the LOAD at the speaker CHANGES and the entire series circuit changes as the current is volts divided by the TOTAL resistance at that point in time. This means the current CHANGES and the WORK at each device (amp output impedance, wires, cross-over and speaker, change. So it is a TIME and frequency thing. But, low load impedance really stress an amps CURRENT as it jumps WAY UP into a small LOAD impedance. Add in reactant that lowers it even more and YIKES if we have a 2-ohm load and lots of reactance (not at near zero). At least the amps output impedance and wires stay the same.

Best,
Galen Gareis

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This continually mystifies me. How do we hear the electric is live v. a recording of an electric guitar through the same amp? It should sound the same, yet it is obvious it is live.

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I have actually achieved some life-like sounds from my stereo… but mostly with the human voice. This may be less due to accuracy of recording or reproduction and more to do with how are brains are programmed to react to certain words or emotive speech.

I have had my head down, concentrating, working and jerked up as I though someone said something to me. I can’t remember the recordings though.

Peace
Bruce in Philly

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