Hi,
I used several amps to drive a sub in a temporary ported box. I feel the sound is weak, one of my 100W ss amp clips but I like the sound before it clips, gainclones (OPA549) sounds also weak. The sub is 12" 300W, how much power must the power amp be capable of to fully drive the sub without clipping.
Any ideas?
JojoD
I used several amps to drive a sub in a temporary ported box. I feel the sound is weak, one of my 100W ss amp clips but I like the sound before it clips, gainclones (OPA549) sounds also weak. The sub is 12" 300W, how much power must the power amp be capable of to fully drive the sub without clipping.
Any ideas?
JojoD
depends on the encolsure.... I've bottomed out a 10inch, 250watt rms sub in a small sealed box using 150watts..... so.... depends on the enclosure really..
Simply put :
There is a region of the subwoofer, where maximum output
is determined by excursion limits. At the lowest frequencies
power can be very modest but it rises rapidly with frequency.
At higher frequencies output is power limited by the amplifier.
High SPL's in the bass are not easy to achieve.
Often thesimplest way of achieving +6dB SPL's
is to build another identical subwoofer.
🙂 sreten.
There is a region of the subwoofer, where maximum output
is determined by excursion limits. At the lowest frequencies
power can be very modest but it rises rapidly with frequency.
At higher frequencies output is power limited by the amplifier.
High SPL's in the bass are not easy to achieve.
Often thesimplest way of achieving +6dB SPL's
is to build another identical subwoofer.
🙂 sreten.
you dumbarse
"depends on the encolsure.... I've bottomed out a 10inch, 250watt rms sub in a small sealed box using 150watts..... so.... depends on the enclosure really.."
howd ya feel
anyone know anything about a 2n3055, anyone want some?
Daniel
"depends on the encolsure.... I've bottomed out a 10inch, 250watt rms sub in a small sealed box using 150watts..... so.... depends on the enclosure really.."
howd ya feel
anyone know anything about a 2n3055, anyone want some?
Daniel
Re: you dumbarse
I'm a dumbarse, and you haven't even worked out how to use the quoting system yet? 😛 lol
and it wasn't actually me who did it... or my sub.. lol so THERE! 😛
priscared said:
I'm a dumbarse, and you haven't even worked out how to use the quoting system yet? 😛 lol
and it wasn't actually me who did it... or my sub.. lol so THERE! 😛
OK I am now confused 
. Low frequency needs less power to achieve? Or is it the other way around? I am only interested in frequencies below 100Hz, so does it really need to be high powered?
Which one is easiest to drive for an amp?
1. Sealed
2. Ported
3. Bandpass (4th order only)
Please clarify, thanks!
JojoD
. Low frequency needs less power to achieve? Or is it the other way around? I am only interested in frequencies below 100Hz, so does it really need to be high powered?Which one is easiest to drive for an amp?
1. Sealed
2. Ported
3. Bandpass (4th order only)
Please clarify, thanks!
JojoD
JojoD818 said:OK I am now confused
Which one is easiest to drive for an amp?
1. Sealed
2. Ported
3. Bandpass (4th order only)
Please clarify, thanks!
JojoD
*shrugs* 300watts rms sub... I wouldn't bother with anything more than 200watts... but if you feel the need, 300watts might be better...... but I don't know the sub, or the box, or anything.. so.. yeah....
SkinnyBoy said:
It's a cheap sub I bought for an experiment. It doesn't have any brand markings but says 300W @ 4 Ohms and is 12" in diameter.
I built a 2 cu. ft. sealed box for testing purposes and tried a gainclone to power it. At low settings, it sounds great but at high settings, it distorts. Must be the gc protection kicking in?
The I used a 100W solid state amp, it plays a lot louder but at high settings, the amp clips (protection kicks in).
So, back to the question... do I really need a huge amp for a sub?
JojoD818 said:
well.. in all honestly.. you SHOULDN"T need a big amp.... I mean.. if its a cheap sub, would you really wanna pay alot for an amp to run it? 😛
Can I get my 2 cents in here 😕
Two things are going to affect the "destruction point" of ANY speaker or dome.
CLIPPING and OVEREXCURSION !
ALL speakers will handle MORE power than they are rated for, But Only If It Is NOT CLIPPING!
HOWEVER, Overexcursion just ONCE, and it's FRIED!
Clipping is this, > DC Voltage in massive amounts for massive time periods < . It simply causes the voice coil to become a heating element (like the one on a electric hot plate) the bobin the voice coil is wound on, must be light weight as to be able to move with the speakers in/out movement, but strong enough to not fall apart while doing so, therefore the compromise is it can't take a lot of heat without melting (plastic) or deforming(composite), or burning (paper), it has no place to give the excess heat to (except the air gap between the magnet poles) so it burns or deforms, and causes the voice-coil wire to rub on the magnet structure, thus eventually breaking the wire or the flex lead.
so SOME speakers will take SOME clipping, (But NOT for long, or large amounts).
Overexcursion, IS the simple act of forcing the speaker's diaphram to knock it'self to death by hitting the basket that holds it inplace, or to push away from the basket with enough force to seperate the spider, and/or lead wires, and/or surround from the basket. the later being MUCH harder to do, but since it's on the "normal" side of a sound wave, yes it can be done.
(Side note: Properly wired speaker will cause a "+" voltage to move away from the basket, where as "-" will move toward... )
1000's might NOT belive this, but it DOES matter which way ALL the speakers in a group are wired (NOT phased, that is simply to make them all work in unison) . Here's an example, take BOTH sets of woofer wires, and reverse them (so both "+" are now the "-" etc. Belive this or not, these speakers will NOT last as long as an identical set, wired the other way, reason ?? The speakers when hit with a massive bass note will wack the frame (basket) and die sooner, than the other set! The other set will attempt excursion outwards, and the limits of the spider and surround will be reached and act as a shock-absorber, and pull the mass of the cone back into the basket.
Oh, someone is going to say "action=oposite reaction", ah... the original bass note was the action, and since some of that action is now taken away by the surround, there is less force to push the cone back into the basket, hence NO slaming into the frame.
Someone else is going to say " but sound waves move both + and - of "0" (actually No they do not, they move + and - of "Null" WE build amplifires that use "0" as null, and no matter what, any sound that is fed to the amp, will start with a "Plus" movement... (just like a cars's starter motor, it don't care which terminal is "+" it will turn the same direction every time, the same with an amp, "+" is the starting point for that waveform for any signal into the amp. Therefore, all notes from the speakers will start with the cone moving outwards when the speaker is wired correctly (watch it, as there are different meanings of "+" eg: most tweeters move the other direction when hooked up +, do a search in it)
(Double side note: medical instrmentation amplifiers are the only amplifiers made that can (if wanted) start a signal waveform on the "-" of things something to do with the human body being reverse of how we build electronic's in the first place.
NOW on to the final chapter in this (WHEW, I'm long winded !😀 ).
Anyhow, Bass notes and power amps, a great rule of thumb " half the frequency, double the power" most "thumpy" bass is somewhere areound the 160hz area (cheap getto-blasters empasize this region, and it's known as "synthetic bass"), (it's also the easyest bass to feel with our body's being a structure of 50% water or something like that, (look up sound propagation in water, you'll find out why this area is so good) onward, the notes below the 160hz area, next octive down is 80hz, next is 40hz, next is 20hz . (These would be "Root" to one harmonic down)
SO, if one is using 150 watts @ 160hz, in order to repoduce a 40hz note correctly, they would need 600 watts ! and at 20hz it would be 1200 watts!!! Most people that claim "MY system does 20hz when the amp is almost clipping"are blowing air from open holes in their body (note I say MOST) the power factors involved get quite huge and since most amp's only have 3db of headroom it' simply not capable of doing so! (however if someone is listening to 160hz note @ 1 watt and whats to hear an 80hz note, at the same volume, they only need 2 watts. )
Here's that rule of thumb again, "half the frequency, double the power"
And who said "I can make a sub sound great with 50 watts" at what SPL ? 80 ?? and over what frequency range > 160-300hz ??
MC Hammer should re-write his HIT..... "It's Getto time"... 😀
Everybody have fun , cuz I know we all LOVE "real bass", don't we 😎
Two things are going to affect the "destruction point" of ANY speaker or dome.
CLIPPING and OVEREXCURSION !
ALL speakers will handle MORE power than they are rated for, But Only If It Is NOT CLIPPING!
HOWEVER, Overexcursion just ONCE, and it's FRIED!
Clipping is this, > DC Voltage in massive amounts for massive time periods < . It simply causes the voice coil to become a heating element (like the one on a electric hot plate) the bobin the voice coil is wound on, must be light weight as to be able to move with the speakers in/out movement, but strong enough to not fall apart while doing so, therefore the compromise is it can't take a lot of heat without melting (plastic) or deforming(composite), or burning (paper), it has no place to give the excess heat to (except the air gap between the magnet poles) so it burns or deforms, and causes the voice-coil wire to rub on the magnet structure, thus eventually breaking the wire or the flex lead.
so SOME speakers will take SOME clipping, (But NOT for long, or large amounts).
Overexcursion, IS the simple act of forcing the speaker's diaphram to knock it'self to death by hitting the basket that holds it inplace, or to push away from the basket with enough force to seperate the spider, and/or lead wires, and/or surround from the basket. the later being MUCH harder to do, but since it's on the "normal" side of a sound wave, yes it can be done.
(Side note: Properly wired speaker will cause a "+" voltage to move away from the basket, where as "-" will move toward... )
1000's might NOT belive this, but it DOES matter which way ALL the speakers in a group are wired (NOT phased, that is simply to make them all work in unison) . Here's an example, take BOTH sets of woofer wires, and reverse them (so both "+" are now the "-" etc. Belive this or not, these speakers will NOT last as long as an identical set, wired the other way, reason ?? The speakers when hit with a massive bass note will wack the frame (basket) and die sooner, than the other set! The other set will attempt excursion outwards, and the limits of the spider and surround will be reached and act as a shock-absorber, and pull the mass of the cone back into the basket.
Oh, someone is going to say "action=oposite reaction", ah... the original bass note was the action, and since some of that action is now taken away by the surround, there is less force to push the cone back into the basket, hence NO slaming into the frame.
Someone else is going to say " but sound waves move both + and - of "0" (actually No they do not, they move + and - of "Null" WE build amplifires that use "0" as null, and no matter what, any sound that is fed to the amp, will start with a "Plus" movement... (just like a cars's starter motor, it don't care which terminal is "+" it will turn the same direction every time, the same with an amp, "+" is the starting point for that waveform for any signal into the amp. Therefore, all notes from the speakers will start with the cone moving outwards when the speaker is wired correctly (watch it, as there are different meanings of "+" eg: most tweeters move the other direction when hooked up +, do a search in it)
(Double side note: medical instrmentation amplifiers are the only amplifiers made that can (if wanted) start a signal waveform on the "-" of things something to do with the human body being reverse of how we build electronic's in the first place.
NOW on to the final chapter in this (WHEW, I'm long winded !😀 ).
Anyhow, Bass notes and power amps, a great rule of thumb " half the frequency, double the power" most "thumpy" bass is somewhere areound the 160hz area (cheap getto-blasters empasize this region, and it's known as "synthetic bass"), (it's also the easyest bass to feel with our body's being a structure of 50% water or something like that, (look up sound propagation in water, you'll find out why this area is so good) onward, the notes below the 160hz area, next octive down is 80hz, next is 40hz, next is 20hz . (These would be "Root" to one harmonic down)
SO, if one is using 150 watts @ 160hz, in order to repoduce a 40hz note correctly, they would need 600 watts ! and at 20hz it would be 1200 watts!!! Most people that claim "MY system does 20hz when the amp is almost clipping"are blowing air from open holes in their body (note I say MOST) the power factors involved get quite huge and since most amp's only have 3db of headroom it' simply not capable of doing so! (however if someone is listening to 160hz note @ 1 watt and whats to hear an 80hz note, at the same volume, they only need 2 watts. )
Here's that rule of thumb again, "half the frequency, double the power"
And who said "I can make a sub sound great with 50 watts" at what SPL ? 80 ?? and over what frequency range > 160-300hz ??
MC Hammer should re-write his HIT..... "It's Getto time"... 😀
Everybody have fun , cuz I know we all LOVE "real bass", don't we 😎
LMAO !!!
after looking at what I posted, and RE-reading Skinnyboy's post above me, I kick myself !!!! )Cheap Sub( LMAO ! (cheap amp) WWAAYY to funny ! good one skinny !
after looking at what I posted, and RE-reading Skinnyboy's post above me, I kick myself !!!! )Cheap Sub( LMAO ! (cheap amp) WWAAYY to funny ! good one skinny !
Ok, so now I must use the biggest amp that I can get to try on this project. For the output not to clip, I must have a huge amp for a clean output right?
Thanks,
JojoD
Thanks,
JojoD
the bigger the more acurate the bass response, with out clipping, hence the speaker lives longer...
(as long as one doesn't over excurt the speaker).
😀
(as long as one doesn't over excurt the speaker).
😀
Polarity?
Is what I think I am reading what I think it is. That always the leading edge of a bass beat is always positive going? I'm sorry but there is no standard here. There is no control whether a given piece of equipment in the signal chain is inverting or non-inverting. No control whatsoever.
It is important to keep relative phase correct betwwen the speakers in a system so they all move the same direction at the same time. However, a leading edge of a bass beat can ge positive or negative going. There is no standard.\
There are so may pieces of inverting equipment in the signal chain between microphone and speaker that absolute polarity is impossible to maintain. Maybe a few audiophile recording places do it but in the mainstream, absolute signal phase is not any paid attention.
Is what I think I am reading what I think it is. That always the leading edge of a bass beat is always positive going? I'm sorry but there is no standard here. There is no control whether a given piece of equipment in the signal chain is inverting or non-inverting. No control whatsoever.
It is important to keep relative phase correct betwwen the speakers in a system so they all move the same direction at the same time. However, a leading edge of a bass beat can ge positive or negative going. There is no standard.\
There are so may pieces of inverting equipment in the signal chain between microphone and speaker that absolute polarity is impossible to maintain. Maybe a few audiophile recording places do it but in the mainstream, absolute signal phase is not any paid attention.
Dan,
I know what you said, about what I said, trust me... WE as humans think one way... It took many years for me to understand this... (Note in the loosest sense)
Here's a trick for you to try in the "real world" get your scope, set it for "edge trigger" with a long decay time as to catch which side of center your pulse caused the display to move) , hook it to the output of a power amp, now send that amp a mili-second pulse of DC 0.2 v or some where around there, try it both ways (+ to input, and - to ground, then reverse them, + to gnd. and - to input..... watch which way the scopes line moves from the center line... it's ALWAYS up...... (+)
Go figure... 😕
P.S. why does a car's starter move the same direction + to post, - to casing, or + to casing, - to post, (OFF car, we wouldn't want to fry any auto electronics hooking the battery up wrong now would we)...
I don't clame to know WHY this happens, only the fact that it does.....
and Oh, your comments all deal with sound "Phase" NOT current/voltage direction, within an electronic "Section" of a said chain of equipment ....
Electronic components must move within the relm of electrons, NOT sound,
It is US (we) that move within the relm of sound, rather than the sound moving within the relm of us.
WOW, really go figure !
I know what you said, about what I said, trust me... WE as humans think one way... It took many years for me to understand this... (Note in the loosest sense)
Here's a trick for you to try in the "real world" get your scope, set it for "edge trigger" with a long decay time as to catch which side of center your pulse caused the display to move) , hook it to the output of a power amp, now send that amp a mili-second pulse of DC 0.2 v or some where around there, try it both ways (+ to input, and - to ground, then reverse them, + to gnd. and - to input..... watch which way the scopes line moves from the center line... it's ALWAYS up...... (+)
Go figure... 😕
P.S. why does a car's starter move the same direction + to post, - to casing, or + to casing, - to post, (OFF car, we wouldn't want to fry any auto electronics hooking the battery up wrong now would we)...
I don't clame to know WHY this happens, only the fact that it does.....
and Oh, your comments all deal with sound "Phase" NOT current/voltage direction, within an electronic "Section" of a said chain of equipment ....
Electronic components must move within the relm of electrons, NOT sound,
It is US (we) that move within the relm of sound, rather than the sound moving within the relm of us.
WOW, really go figure !
Re: Polarity?
Dan, BTW, sorry, but I must disaggree with that statement (NOT trying to slam you, sorry)
But, yes there is, the phase of a microphone can control what "gets to the sum" of 2 or more sound board channels, if 2 mics are on a snare drum, both pointed to each other, say one from the top pointing down, and one from the bottom pointing up, the sum of the 2 wavefronts will cancel each other to the most part, and the snare will sound very "thin", however, if one uses a "phase invert connector on the lower mic cable, or throws the phase switch on the pre-input of the sound board (most good ones have them) you can make a snare sound very "thick" with this one trick.... BUT, here's the thing.... the board's SUM of both channels is still "leading edge + going" (that is why the SUM of the original microphone setup canceled each other BUT you could still hear part of the sum-ed siginal, HAD the signal actually been "out of phase" within the sound board, the sum would have been 0, as is NO sound what so ever, as electrons are still electrons, and NO, a sound board is NOT an atom smasher !
they are still electrons no mater how you push them through the wires....
dmfraser said:
Dan, BTW, sorry, but I must disaggree with that statement (NOT trying to slam you, sorry)
But, yes there is, the phase of a microphone can control what "gets to the sum" of 2 or more sound board channels, if 2 mics are on a snare drum, both pointed to each other, say one from the top pointing down, and one from the bottom pointing up, the sum of the 2 wavefronts will cancel each other to the most part, and the snare will sound very "thin", however, if one uses a "phase invert connector on the lower mic cable, or throws the phase switch on the pre-input of the sound board (most good ones have them) you can make a snare sound very "thick" with this one trick.... BUT, here's the thing.... the board's SUM of both channels is still "leading edge + going" (that is why the SUM of the original microphone setup canceled each other BUT you could still hear part of the sum-ed siginal, HAD the signal actually been "out of phase" within the sound board, the sum would have been 0, as is NO sound what so ever, as electrons are still electrons, and NO, a sound board is NOT an atom smasher !
they are still electrons no mater how you push them through the wires....
You're wrong about phase and starter motors.
First the easy one...Starter motors
The feild and armature are wound in series. If you reverse polarities, you change the north poles to south poles on both the feild and armature, you've maintained the relative attraction and repulsion forces. This isn't the case on some marine and small engine starters that use permanent magnets for the feild. This is what makes your power windows go up and down. All a/c brush motors (like in hand held power tools) run in one direction regardless of polarity and can run on d/c if the brushes don't burn out. The reverse on power drills is done by reversing the polarity of the feild with respect to the armature.
As for amplifiers, their will track (within their distortion spec) their input be it positive or negative and regardless which swing comes first. If you place a mike on the side of a kick drum opposite the mallet, you will always see a plus swing first (if your system maintains absolute phase). However, if you place the same mike on the other side near the mallet, you will see a negative swing first due to the rareification of the air sucking the diaphram out rather than the pressure pushing it in.
First the easy one...Starter motors
The feild and armature are wound in series. If you reverse polarities, you change the north poles to south poles on both the feild and armature, you've maintained the relative attraction and repulsion forces. This isn't the case on some marine and small engine starters that use permanent magnets for the feild. This is what makes your power windows go up and down. All a/c brush motors (like in hand held power tools) run in one direction regardless of polarity and can run on d/c if the brushes don't burn out. The reverse on power drills is done by reversing the polarity of the feild with respect to the armature.
As for amplifiers, their will track (within their distortion spec) their input be it positive or negative and regardless which swing comes first. If you place a mike on the side of a kick drum opposite the mallet, you will always see a plus swing first (if your system maintains absolute phase). However, if you place the same mike on the other side near the mallet, you will see a negative swing first due to the rareification of the air sucking the diaphram out rather than the pressure pushing it in.
Absolute phasing is impossible
Besides-Would it really matter? read lots of boring articles to find out(hopefully written by well meaning non liar article writers)
i dont fret with things that dont seem to matter
If ur sub isnt making much sound with 100w id examine the efficiency of the speaker and the box alignment as 200w will only give 3db more sound assuming no loses. Make abasshorn and get 120db no sweat
🙂
Besides-Would it really matter? read lots of boring articles to find out(hopefully written by well meaning non liar article writers)
i dont fret with things that dont seem to matter
If ur sub isnt making much sound with 100w id examine the efficiency of the speaker and the box alignment as 200w will only give 3db more sound assuming no loses. Make abasshorn and get 120db no sweat
🙂
Sorry Brian,
I'm NOT the one talking about Phase.... I'm the one talking about VOLTAGE and electrons moving. (one of the other guys was trying to relate "phase" within a total electronics systems from mic to speaker.
As far as starter motors, yes, P/M motors will reverse this is the entire reasoning of why we are "preceiving" that an amp actually produces negative voltages and swings to the other side of "0" volts. However, why is that ?? here's the thing... the electrons will move against the magnet E/M force, however, when we place electrons in the feild/armature way of things, we are NOT dealing with a true magnet, we are dealing with E/E force, and the same rules do NOT apply (a true magnet can NOT be made to reverse poles, BUT something that HAS been magnetised BY a true magnet OR an induced magnet can) and yes, the relationship thing of feild to armature I aggree with you.
WHAT I do dissagree with is the initial swing of the siginal on the output section of a power amp (NOT ANYTHING "Up stream" as they are all "within the biased chain" , and the only way to solve this, is go back to my eartlyer post, an read the section on using a scope and set it for "triggered sweep" (you must of missed that), and DO the experement, yourself, that is the only way I can say this, as for years, I also thought the same way as you, and others.....
We assume that a waveform, since it, itself is a vibration of sound that the waveform does the same thing within an amp (well yes it does to an extent, the extent of veiwing it within a biased (offset voltage) circuit, you see, when we look at the waveform we generally are using a scope and referencing to earth ground, (Not amp ground) BUT, an amp's ground is "offset" from true "earth ground" because we are using both a positive power supply rail AND a negitive power supply rail, both being ASSUMED to the "0 volt" center point (BIASED ground (offset voltage), NOT earth ground) however the way you want to put it, when you are looking at the picture of a waveform, you are looking at a "biased" picture, HEY, what is "A.C." when we are dealing with voltage, HOW is it, that ONE wire into an electric poll's stepdown transformer, can and does produce 2 pole power ? (the same as a centertaped power transformer) that is how... so NOW think of this.... that center tap @ 0 volts, is that not "setting a bias" within the powersupply so our thinking can preceive a voltage going minus of "0" when the source voltage that is driving it does NOT do that in the first place ??
Hey, Why can't we connect the negitive of the speaker outputs to earth ground, because it will fry the output transistors, BUT WHY ! isn't the negitive speaker terminal MINUS voltage ??? (NO it's NOT), it's negitive in relationship to a Biased (offset) floating ground) that is fictious in the first place, so we can preceive that the siginal is going "negitive" for the other "side" of the waveform. However that negitive voltage is actually at a + level in reference to true "earth ground" and that is why it would induce current flow in the first place.
Brain, go read my post about using a triggered scope, then come back and we will continue talking about this, OK ??
I once (and for years) also thought the same way you do. (NOT being an A$%,) I really understand where you are coming from... go do the experement.
Oh, and BTW, the P/magnet thing... gawd, ain't speakers a thing that uses a P/Magnet ???? why are the terminals marked + and - when they are used in want you want to say is an AC circuit ? , doesn't + and - mean DC ?? (well it does, in reference to a P/magnet) why arn't the terminals on BOTH the amp AND the speaker called "HOT and Neutral" like the AC line ???
REALLY, there are reasons for these discrepencies, it's NOT a fluke or accident that they are called what they are called...
I'm NOT the one talking about Phase.... I'm the one talking about VOLTAGE and electrons moving. (one of the other guys was trying to relate "phase" within a total electronics systems from mic to speaker.
As far as starter motors, yes, P/M motors will reverse this is the entire reasoning of why we are "preceiving" that an amp actually produces negative voltages and swings to the other side of "0" volts. However, why is that ?? here's the thing... the electrons will move against the magnet E/M force, however, when we place electrons in the feild/armature way of things, we are NOT dealing with a true magnet, we are dealing with E/E force, and the same rules do NOT apply (a true magnet can NOT be made to reverse poles, BUT something that HAS been magnetised BY a true magnet OR an induced magnet can) and yes, the relationship thing of feild to armature I aggree with you.
WHAT I do dissagree with is the initial swing of the siginal on the output section of a power amp (NOT ANYTHING "Up stream" as they are all "within the biased chain" , and the only way to solve this, is go back to my eartlyer post, an read the section on using a scope and set it for "triggered sweep" (you must of missed that), and DO the experement, yourself, that is the only way I can say this, as for years, I also thought the same way as you, and others.....
We assume that a waveform, since it, itself is a vibration of sound that the waveform does the same thing within an amp (well yes it does to an extent, the extent of veiwing it within a biased (offset voltage) circuit, you see, when we look at the waveform we generally are using a scope and referencing to earth ground, (Not amp ground) BUT, an amp's ground is "offset" from true "earth ground" because we are using both a positive power supply rail AND a negitive power supply rail, both being ASSUMED to the "0 volt" center point (BIASED ground (offset voltage), NOT earth ground) however the way you want to put it, when you are looking at the picture of a waveform, you are looking at a "biased" picture, HEY, what is "A.C." when we are dealing with voltage, HOW is it, that ONE wire into an electric poll's stepdown transformer, can and does produce 2 pole power ? (the same as a centertaped power transformer) that is how... so NOW think of this.... that center tap @ 0 volts, is that not "setting a bias" within the powersupply so our thinking can preceive a voltage going minus of "0" when the source voltage that is driving it does NOT do that in the first place ??
Hey, Why can't we connect the negitive of the speaker outputs to earth ground, because it will fry the output transistors, BUT WHY ! isn't the negitive speaker terminal MINUS voltage ??? (NO it's NOT), it's negitive in relationship to a Biased (offset) floating ground) that is fictious in the first place, so we can preceive that the siginal is going "negitive" for the other "side" of the waveform. However that negitive voltage is actually at a + level in reference to true "earth ground" and that is why it would induce current flow in the first place.
Brain, go read my post about using a triggered scope, then come back and we will continue talking about this, OK ??
I once (and for years) also thought the same way you do. (NOT being an A$%,) I really understand where you are coming from... go do the experement.
Oh, and BTW, the P/magnet thing... gawd, ain't speakers a thing that uses a P/Magnet ???? why are the terminals marked + and - when they are used in want you want to say is an AC circuit ? , doesn't + and - mean DC ?? (well it does, in reference to a P/magnet) why arn't the terminals on BOTH the amp AND the speaker called "HOT and Neutral" like the AC line ???
REALLY, there are reasons for these discrepencies, it's NOT a fluke or accident that they are called what they are called...
The trigger on my scope triggers when the signal exceedes the threshold as the signal is rising when the trigger slope is set to "+" or when it dips below the threshold when the signal is falling when set to "-"
Every amp I've ever seen will output any signal that is fed to it if it's within its bandwidth and voltage range. Your results I would think are a triggering phenomina from your scope. What does your amp do when you feed it a sine wave that starts with a negative swing? Skip the first 180 degrees then start working? or does it produce a inverted sine wave so it does positive first?
I don't mean to start any ill feelings. And I'm only refering to what an audio amp does, not to what a guitar pickup produces. Amps amplify the signal they are given. Regardles of the transient shape that starts the signal, they output the same swing (or opposite if they are inverting) they are fed.
Every amp I've ever seen will output any signal that is fed to it if it's within its bandwidth and voltage range. Your results I would think are a triggering phenomina from your scope. What does your amp do when you feed it a sine wave that starts with a negative swing? Skip the first 180 degrees then start working? or does it produce a inverted sine wave so it does positive first?
I don't mean to start any ill feelings. And I'm only refering to what an audio amp does, not to what a guitar pickup produces. Amps amplify the signal they are given. Regardles of the transient shape that starts the signal, they output the same swing (or opposite if they are inverting) they are fed.
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