-- on cag
cag's posts seem to indicate he is a fairly old-school, hands-on engineer and entheusiest. that said, many of his posts seem ambiguous -- either exactly correct, completely wrong, or missing key information. still, experience does count for something, so its probably best to reread the posts and see if there is some other meaning that might make more sense.
I sometimes think of star trek when reading the posts (the subwoofer's harmonic syncronism is balenenced using aperiodic excitation, creating a musical sound -- sweet, lots of long words followed by a conclusion everyone understands!)
I especially dislike the "half of amplifier" part. i see two explanations, one exactly correct, one confusing. its really hard to tell which one was intended.
-- on EMF
in terms of back-emf though, I'm placing all my money on the magnetic gap + moving coil. you're using an electrical force to create a mechanical force -- well its a two way street. the cone's mass can store energy and then PULL the coil through the gap which FORCES energy to flow back into the amplifier. likewise any springiness that is strected/compressed will PUSH the coil and again return energy from the mechanical system to the electrical system.
-- Response to N2
n2, back-emf, in terms of damping factor of the amp is a different issue. the issue you are thinking of is in terms of the amp affecting the speaker's response. the issue in question here is the speaker affecting the amplifier's efficiency.
--on seeing a load. parallel speakers
imagine you are blindfolded. you are led to a weight machine. you are handed a bar and told to lift some weight. what is the weight you are lifting? well, its printed on the weights.
ok, lets say someone adds weight to each end (speakers in parallel). now you're doing more work, but each weight is still moving the same amount. this is very similar to speakers in parallel. each speaker receives as much power as it would if it were the only thing connected (each weight moves just as much as if it were the only one) but adding more speakers means you have more power, but just because each speaker draws power (adding weights means you do more work, but just because you have to move more weight).
-- on "seeing a load", bridged amplifiers
imagine you are blindfolded. you are led to a weight machine. you are handed a bar and told to lift some weight. what is the weight you are lifting? well, its printed on the weights.
ok, lets say you have a spotter -- the spotter can help you -- so the weight you see can be LESS then the actual weights. likewise, lets say the spotter does the opposite and pushes down on the weights -- now they SEEM heavier. this is similar to why an amplifier might SEE a different load then the actual load -- some other amplifier channel may be actively opposing it. for a bridged amplifier, each channel is trying to do the exact opposite thing. this ends up really putting power to the woofer, but at the same time each channel is now working harder then before.
cag's posts seem to indicate he is a fairly old-school, hands-on engineer and entheusiest. that said, many of his posts seem ambiguous -- either exactly correct, completely wrong, or missing key information. still, experience does count for something, so its probably best to reread the posts and see if there is some other meaning that might make more sense.
I sometimes think of star trek when reading the posts (the subwoofer's harmonic syncronism is balenenced using aperiodic excitation, creating a musical sound -- sweet, lots of long words followed by a conclusion everyone understands!)
I especially dislike the "half of amplifier" part. i see two explanations, one exactly correct, one confusing. its really hard to tell which one was intended.
-- on EMF
in terms of back-emf though, I'm placing all my money on the magnetic gap + moving coil. you're using an electrical force to create a mechanical force -- well its a two way street. the cone's mass can store energy and then PULL the coil through the gap which FORCES energy to flow back into the amplifier. likewise any springiness that is strected/compressed will PUSH the coil and again return energy from the mechanical system to the electrical system.
-- Response to N2
n2, back-emf, in terms of damping factor of the amp is a different issue. the issue you are thinking of is in terms of the amp affecting the speaker's response. the issue in question here is the speaker affecting the amplifier's efficiency.
--on seeing a load. parallel speakers
imagine you are blindfolded. you are led to a weight machine. you are handed a bar and told to lift some weight. what is the weight you are lifting? well, its printed on the weights.
ok, lets say someone adds weight to each end (speakers in parallel). now you're doing more work, but each weight is still moving the same amount. this is very similar to speakers in parallel. each speaker receives as much power as it would if it were the only thing connected (each weight moves just as much as if it were the only one) but adding more speakers means you have more power, but just because each speaker draws power (adding weights means you do more work, but just because you have to move more weight).
-- on "seeing a load", bridged amplifiers
imagine you are blindfolded. you are led to a weight machine. you are handed a bar and told to lift some weight. what is the weight you are lifting? well, its printed on the weights.
ok, lets say you have a spotter -- the spotter can help you -- so the weight you see can be LESS then the actual weights. likewise, lets say the spotter does the opposite and pushes down on the weights -- now they SEEM heavier. this is similar to why an amplifier might SEE a different load then the actual load -- some other amplifier channel may be actively opposing it. for a bridged amplifier, each channel is trying to do the exact opposite thing. this ends up really putting power to the woofer, but at the same time each channel is now working harder then before.
