I have a simple question: If I use an 800W RMS amp on a 600W RMS sub,
will the sub always see 800W? If I were to turn the gain down below its
optimal setting, would this reduce the amount of power being given to the
sub?

I am asking this because I see numerous people claiming they've used an
amp that is much too powerful for their sub, but they claim they're OK if
they keep the gain down.

However I've also read that that turning the gain down does not reduce
the power being fed to the sub.

Don

They're too many variables to give a solid yes or no answer to you question.
Theoretically, you could turn down the amp gains and match the system so it
wouldn't overdrive, but, they're could be one cd that would have a bass
transient that could push the amp to full power. The amp could also be
underated and actually deliver more than 800 watts. The sub could be
underated and not actually handle 600 watts.
If it's a good sub, it will probably be fine.


"Don Joe" wrote in message
news
I have a simple question: If I use an 800W RMS amp on a 600W RMS sub,
will the sub always see 800W? If I were to turn the gain down below its
optimal setting, would this reduce the amount of power being given to the
sub?

I am asking this because I see numerous people claiming they've used an
amp that is much too powerful for their sub, but they claim they're OK if
they keep the gain down.

However I've also read that that turning the gain down does not reduce
the power being fed to the sub.

Don

"Don Joe" wrote in message
news | I have a simple question: If I use an 800W RMS amp on a 600W RMS sub,
| will the sub always see 800W? If I were to turn the gain down below its
| optimal setting, would this reduce the amount of power being given to the
| sub?
|
| I am asking this because I see numerous people claiming they've used an
| amp that is much too powerful for their sub, but they claim they're OK if
| they keep the gain down.
|
| However I've also read that that turning the gain down does not reduce
| the power being fed to the sub.
|
| Don

If you have an 800watt amp, and you hook it up to your sub, and you turn the
volume control to zero, will you blow your sub?

IOW, that sub is only seeing 800 watts when its being driven to its highest
output before clipping (and more than 800 after clipping)

You won't have a problem. Overdriving is a common practice, as long as you
know when your sub has reached it limits..in which case just keep the volume
below that.

As far as the gain setting question, I'm not an expert, but turning the gain
down reduces the amount of power going to the sub. I woudn't worry about
that though...just set your gains in the normal fashion and you should be
fine.

Tony


--



What's more likely? That an all-powerful mysterious god created the
universe and then decided not to give any proof of his existence? Or, that
he simply doesn't exist at all? And that we created him so that we wouldn't
have to feel so small and alone. -Eleanor Arroway, Contact

"Gary Rodgers" wrote in message
k.net...

"Don Joe" wrote in message
news | I have a simple question: If I use an 800W RMS amp on a 600W RMS sub,
| will the sub always see 800W? If I were to turn the gain down below its
| optimal setting, would this reduce the amount of power being given to
the
| sub?
|
| I am asking this because I see numerous people claiming they've used an
| amp that is much too powerful for their sub, but they claim they're OK
if
| they keep the gain down.
|
| However I've also read that that turning the gain down does not reduce
| the power being fed to the sub.
|
| Don

If you have an 800watt amp, and you hook it up to your sub, and you turn
the
volume control to zero, will you blow your sub?

IOW, that sub is only seeing 800 watts when its being driven to its
highest
output before clipping (and more than 800 after clipping)

Don Joe wrote:
I have a simple question: If I use an 800W RMS amp on a 600W RMS sub,
will the sub always see 800W? If I were to turn the gain down below its
optimal setting, would this reduce the amount of power being given to the
sub?

I am asking this because I see numerous people claiming they've used an
amp that is much too powerful for their sub, but they claim they're OK if
they keep the gain down.

However I've also read that that turning the gain down does not reduce
the power being fed to the sub.


Please see the rec.audio.car FAQ (http://mobileaudio.com/rac-faq), both
of these questions are answered.

5.6 How do I set the gains on my amp?

5.21 What's worse for a speaker, too much or too little power?


Good luck,



Ian D. Bjorhovde
rec.audio.car FAQ Maintainer


-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

An amplifier capable of 800wrms doesn't supply all of it all the time. The
sub will draw the wattage it needs as it needs it. Subwoofer don't have
watts. They are rated at a maximum of so many watts. Turning down the gain
is the same as reducing the volume of a signal. There is no such thing as
power being "given" to a sub. Subs blow from too little wattage, not to
much. The gain setting on any quality amp should never exceed 50%. A sub has
no personality and cannot "see" an amount of wattage. It is an acoustic
motor which runs on a fuel called wattage. It takes only what it needs. P.



"Don Joe" wrote in message
news
I have a simple question: If I use an 800W RMS amp on a 600W RMS sub,
will the sub always see 800W? If I were to turn the gain down below its
optimal setting, would this reduce the amount of power being given to the
sub?

I am asking this because I see numerous people claiming they've used an
amp that is much too powerful for their sub, but they claim they're OK if
they keep the gain down.

However I've also read that that turning the gain down does not reduce
the power being fed to the sub.

Don

An amplifier capable of 800wrms doesn't supply all of it all the time. The
sub will draw the wattage it needs as it needs it. Subwoofer don't have
watts. They are rated at a maximum of so many watts. Turning down the
gain
is the same as reducing the volume of a signal. There is no such thing as
power being "given" to a sub. Subs blow from too little wattage, not to
much. The gain setting on any quality amp should never exceed 50%. A sub
has
no personality and cannot "see" an amount of wattage. It is an acoustic
motor which runs on a fuel called wattage. It takes only what it needs. P.

Peter, your mistakes have been corrected time and time again by many folks
in this newsgroup, yet you still repeat the same mantra.

For the hundredth time, no your sub doesn't "draw the wattage it needs as it
needs it."

You're wrong when you say "subs blow from too little wattage, not too much."
Such a concept defies the laws of physics.

You're wrong when you say "the gain setting on any quality amp should never
exceed 50%."

Please, learn the error of your ways and cast aside the salesman training
exercises your mind has been littered with.

Peter Klein wrote:

An amplifier capable of 800wrms doesn't supply all of it all the time. The
sub will draw the wattage it needs as it needs it. Subwoofer don't have
watts. They are rated at a maximum of so many watts. Turning down the
gain is the same as reducing the volume of a signal. There is no such
thing as power being "given" to a sub. Subs blow from too little wattage,
not to much. The gain setting on any quality amp should never exceed 50%.
A sub has no personality and cannot "see" an amount of wattage. It is an
acoustic motor which runs on a fuel called wattage. It takes only what it
needs. P.

Actually, too *little* power won't damage a speaker - only too *much* power.
The problem usually comes from overdriving the amplifier into clipping. An
amplifier that's clipping will put out a LOT more power than either its RMS
or peak power ratings might suggest, since once the amp starts clipping,
turning up the volume knob further will still cause the output power to
increase. An amp that's capable of providing 200W RMS or 400W peak might
easily put out 700-800W if you're clipping the hell out of it. This can
lead to a "200-watt" amp damaging a "500-watt" subwoofer.

There's also some conjecture that the cooling capability (and therefore, the
power-handling capability) of a subwoofer might be reduced when it's being
fed a clipped signal as opposed to an unclipped signal. This hasn't been
demonstrated yet, and it's only a secondary issue anyway. The main thing
is that if you are using too small of an amplifier, and routinely driving
it into clipping, it's putting out a lot more power than you might think,
and that's what damages the sub.

As for your statement that "The gain setting on any quality amp should never
exceed 50%.", that's completely wrong. The proper gain setting depends
solely on the voltage of the preamp-level inputs and the range of input
voltage that the amplifier is designed to accept.

If you have an amplifier that is designed to accept a wide range of input
voltages, like 0.5V - 8.0V, and you use it with a head unit that has
standard preouts (less than one volt), than you're going to have to turn
the gain on the amplifier up quite a bit, probably well past the 50% mark,
in order to extract full output from the amp. On the other hand, if you
have an amp that's only designed to accept input voltages in the .5V-2V
range, and you have a head unit with 8V preouts, you'll have to turn the
gain on the amp down quite low to avoid overdriving the amp.

Where you set the gain on the amp has nothing to do with the quality of the
amp, it's just a means of matching voltage levels between the output stage
of your preamp and the input stage of your amplifier.

Scott Gardner

Actually, too *little* power won't damage a speaker - only too *much*
power.
The problem usually comes from overdriving the amplifier into clipping.
An
amplifier that's clipping will put out a LOT more power than either its
RMS
or peak power ratings might suggest, since once the amp starts clipping,
turning up the volume knob further will still cause the output power to
increase. An amp that's capable of providing 200W RMS or 400W peak might
easily put out 700-800W if you're clipping the hell out of it. This can
lead to a "200-watt" amp damaging a "500-watt" subwoofer.

How is a 200 wrms amplifier going to output 700-800 watts when clipping?


There's also some conjecture that the cooling capability (and therefore,
the
power-handling capability) of a subwoofer might be reduced when it's being
fed a clipped signal as opposed to an unclipped signal. This hasn't been
demonstrated yet, and it's only a secondary issue anyway. The main thing
is that if you are using too small of an amplifier, and routinely driving
it into clipping, it's putting out a lot more power than you might think,
and that's what damages the sub.

Well said.

MZ wrote:

Actually, too *little* power won't damage a speaker - only too *much*
power.
The problem usually comes from overdriving the amplifier into clipping.
An
amplifier that's clipping will put out a LOT more power than either its
RMS
or peak power ratings might suggest, since once the amp starts clipping,
turning up the volume knob further will still cause the output power to
increase. An amp that's capable of providing 200W RMS or 400W peak might
easily put out 700-800W if you're clipping the hell out of it. This can
lead to a "200-watt" amp damaging a "500-watt" subwoofer.

How is a 200 wrms amplifier going to output 700-800 watts when clipping?


I'll try to find a specific reference, but it's basically the same way the
less-scrupulous amp manufacturers can call something a "1000-watt" amp when
it only puts out 200-300 WRMS. They basically overdrive the hell out of
the amp until the output is essentially nothing but a square wave, and
measure the power output right before the amp catches fire.

If an amp can produce 200 WRMS or 400W peak without clipping, and you turn
up the volume knob even further, the output power will continue to
increase, even after the output waveform has begun to clip. The average
output power will continue to increase until the point where the output is
nothing more than a square wave, slamming back and forth between the
positive and negative rail voltages.

Again, I'll try to find a reference that's a little more specific.

Scott Gardner

How is a 200 wrms amplifier going to output 700-800 watts when clipping?


I'll try to find a specific reference, but it's basically the same way the
less-scrupulous amp manufacturers can call something a "1000-watt" amp
when
it only puts out 200-300 WRMS. They basically overdrive the hell out of
the amp until the output is essentially nothing but a square wave, and
measure the power output right before the amp catches fire.

If an amp can produce 200 WRMS or 400W peak without clipping, and you turn
up the volume knob even further, the output power will continue to
increase, even after the output waveform has begun to clip. The average
output power will continue to increase until the point where the output is
nothing more than a square wave, slamming back and forth between the
positive and negative rail voltages.

Again, I'll try to find a reference that's a little more specific.

Right, but their practices include more than just clipping. They often run
a high supply voltage, measure the transients, etc, in order to get the BS
ratings on the box. But in the case of clipping, you'll never exceed the
theoretical increase in power going from a sine to a square of the same
amplitude -- that is, doubling the power. In fact, you'll never reach this
amount of power either due to a number of factors, such as Vrail sag on the
amplifier end of things and the impedance characteristics of the driver
itself.

MZ wrote:

How is a 200 wrms amplifier going to output 700-800 watts when
clipping?


I'll try to find a specific reference, but it's basically the same way
the less-scrupulous amp manufacturers can call something a "1000-watt"
amp
when
it only puts out 200-300 WRMS. They basically overdrive the hell out of
the amp until the output is essentially nothing but a square wave, and
measure the power output right before the amp catches fire.

If an amp can produce 200 WRMS or 400W peak without clipping, and you
turn up the volume knob even further, the output power will continue to
increase, even after the output waveform has begun to clip. The average
output power will continue to increase until the point where the output
is nothing more than a square wave, slamming back and forth between the
positive and negative rail voltages.

Again, I'll try to find a reference that's a little more specific.

Right, but their practices include more than just clipping. They often
run a high supply voltage, measure the transients, etc, in order to get
the BS
ratings on the box. But in the case of clipping, you'll never exceed the
theoretical increase in power going from a sine to a square of the same
amplitude -- that is, doubling the power. In fact, you'll never reach
this amount of power either due to a number of factors, such as Vrail sag
on the amplifier end of things and the impedance characteristics of the
driver itself.

Yep, that's the increase I was talking about. If an amplifer can produce
400W without any clipping (a sine wave with an amplitude exactly equal to
the rail voltage), then it can theoretically produce twice that much power
if it's driven to hard clipping (a square wave output with an amplitude
equal to the rail voltage). I realize that the doubling is only
theoretical, for the reasons you mentioned above, but my original point was
that the power delivered by an amp that's overdriven into hard clipping
will be *significantly* higher than the maximum unclipped output from the
same amp. This can cause damage to a subwoofer, even though the ratings of
the amplifier and the subwoofer might lead one to believe that no damage
would be possible. (e.g. a 300WRMS amp and a 500WRMS subwoofer.)

Scott Gardner

--
Mark
remove "remove" and "spam" to reply


"Scott Gardner" wrote in message
news:1mjGc.7197$pY2.1847@lakeread01...
MZ wrote:

How is a 200 wrms amplifier going to output 700-800 watts when
clipping?


I'll try to find a specific reference, but it's basically the same way
the less-scrupulous amp manufacturers can call something a "1000-watt"
amp
when
it only puts out 200-300 WRMS. They basically overdrive the hell out
of
the amp until the output is essentially nothing but a square wave, and
measure the power output right before the amp catches fire.

If an amp can produce 200 WRMS or 400W peak without clipping, and you
turn up the volume knob even further, the output power will continue to
increase, even after the output waveform has begun to clip. The
average
output power will continue to increase until the point where the output
is nothing more than a square wave, slamming back and forth between the
positive and negative rail voltages.

Again, I'll try to find a reference that's a little more specific.

Right, but their practices include more than just clipping. They often
run a high supply voltage, measure the transients, etc, in order to get
the BS
ratings on the box. But in the case of clipping, you'll never exceed
the
theoretical increase in power going from a sine to a square of the same
amplitude -- that is, doubling the power. In fact, you'll never reach
this amount of power either due to a number of factors, such as Vrail
sag
on the amplifier end of things and the impedance characteristics of the
driver itself.

Yep, that's the increase I was talking about. If an amplifer can produce
400W without any clipping (a sine wave with an amplitude exactly equal to
the rail voltage), then it can theoretically produce twice that much power
if it's driven to hard clipping (a square wave output with an amplitude
equal to the rail voltage).

Right, but your initial post said 200wrms - 700-800 watts clipping.

I realize that the doubling is only
theoretical, for the reasons you mentioned above, but my original point
was
that the power delivered by an amp that's overdriven into hard clipping
will be *significantly* higher than the maximum unclipped output from the
same amp. This can cause damage to a subwoofer, even though the ratings
of
the amplifier and the subwoofer might lead one to believe that no damage
would be possible. (e.g. a 300WRMS amp and a 500WRMS subwoofer.)

Yep. And in fact your original sentiment was correct. You tend to more
than double the output, mostly because of what Rane refers to as "dynamic
compression". This is essentially a decrease in the crest factor (ie. a
compression of the dynamic range) because you're hitting the ceiling on the
loud portions but you continue to increase output on the soft portions.
However, this does not mean a 200 wrms amp will deliver 700-800 watts.
Rather, it means that under normal "unclipped" operation, you're not
delivering 200 watts to your speaker because of the dynamic nature of music.

I was going to reply to Peter's post of peculiar prose, but I ran out of
time and had to run a few errands. I see that Mark beat me to it.

Tony


--



What's more likely? That an all-powerful mysterious god created the
universe and then decided not to give any proof of his existence? Or, that
he simply doesn't exist at all? And that we created him so that we wouldn't
have to feel so small and alone. -Eleanor Arroway, Contact

"Peter Klein" wrote in message
news:MvgGc.28836$XM6.20268@attbi_s53...
An amplifier capable of 800wrms doesn't supply all of it all the time. The
sub will draw the wattage it needs as it needs it. Subwoofer don't have
watts. They are rated at a maximum of so many watts. Turning down the
gain
is the same as reducing the volume of a signal. There is no such thing as
power being "given" to a sub. Subs blow from too little wattage, not to
much. The gain setting on any quality amp should never exceed 50%. A sub
has
no personality and cannot "see" an amount of wattage. It is an acoustic
motor which runs on a fuel called wattage. It takes only what it needs. P.



"Don Joe" wrote in message
news
I have a simple question: If I use an 800W RMS amp on a 600W RMS sub,
will the sub always see 800W? If I were to turn the gain down below its
optimal setting, would this reduce the amount of power being given to
the
sub?

I am asking this because I see numerous people claiming they've used an
amp that is much too powerful for their sub, but they claim they're OK
if
they keep the gain down.

However I've also read that that turning the gain down does not reduce
the power being fed to the sub.

Don

MZ wrote:


Yep.Â*Â*AndÂ*inÂ*factÂ*yourÂ*originalÂ*sentimentÂ* wasÂ*correct.Â*Â*YouÂ*tendÂ*toÂ*more
than double the output, mostly because of what Rane refers to as "dynamic
compression".Â*Â*ThisÂ*isÂ*essentiallyÂ*aÂ*decreas eÂ*inÂ*theÂ*crestÂ*factorÂ*(ie.Â*a
compression of the dynamic range) because you're hitting the ceiling on
the loud portions but you continue to increase output on the soft
portions. However, this does not mean a 200 wrms amp will deliver 700-800
watts. Rather, it means that under normal "unclipped" operation, you're
not delivering 200 watts to your speaker because of the dynamic nature of
music.


That makes sense. I was using the 400W peak number, and then doubling it
based on going from unclipped output to hard clipping. I realized that
that the doubling was only a theoretical maximum, so that's why I used
"700-800W" rather than simply 800W.

So, if you have an amp that's accurately rated at 200WRMS, how much power
would you guess it's delivering to the sub if you overdrive it into hard
clipping?

The other interesting thing about dynamic compression is that I'm seeing it
introduced on purpose quite frequently on modern CD recordings, in an
effort to increase the overall volume of a song without introducing
clipping. FM radio stations do it as well, to make their signal louder
than other stations' signals without running afoul of the FCC.

Scott Gardner

That makes sense. I was using the 400W peak number, and then doubling it
based on going from unclipped output to hard clipping. I realized that
that the doubling was only a theoretical maximum, so that's why I used
"700-800W" rather than simply 800W.

So, if you have an amp that's accurately rated at 200WRMS, how much power
would you guess it's delivering to the sub if you overdrive it into hard
clipping?

Depends entirely on the music, and just how much overdrive we're talking
about. If we were talking about steady tones, then the
doubling-minus-losses estimate is pretty clear cut. But with music, which
barely gets to the 200 watt level under normal conditions, it's much harder
to quantify.

It's important to note that when I say it doesn't get to 200 watts under
normal conditions, I don't mean the transients don't get there. Rather, I
mean if you average the power of the signal on the order of *seconds*, it's
not a steady 200 watts like what you'd see with steady tones.

Maybe I'll do a simulation in matlab later...

The other interesting thing about dynamic compression is that I'm seeing
it
introduced on purpose quite frequently on modern CD recordings, in an
effort to increase the overall volume of a song without introducing
clipping. FM radio stations do it as well, to make their signal louder
than other stations' signals without running afoul of the FCC.

Yeah, that's a good parallel. Hence, you're more likely to blow your
speakers with (unclipped) modern pop music than with (unclipped) classical
music! Or something with a comparable dynamic range.

MZ wrote:


The other interesting thing about dynamic compression is that I'm seeing
it
introduced on purpose quite frequently on modern CD recordings, in an
effort to increase the overall volume of a song without introducing
clipping. FM radio stations do it as well, to make their signal louder
than other stations' signals without running afoul of the FCC.

Yeah, that's a good parallel. Hence, you're more likely to blow your
speakers with (unclipped) modern pop music than with (unclipped) classical
music! Or something with a comparable dynamic range.

I didn't think too much about dynamic range until I started recording a
bunch of my vinyl albums and CDs to the computer. The CD recordings
sounded louder overall than the vinyl recordings, even when I normalized
the recordings so that the peaks were of the same amplitude.

I finally ended up recording three older songs from vinyl, and then recorded
the same three songs from CDs. When I looked at the peak and RMS levels of
the output, I found that for all three songs, the peak levels were almost
the same for both the CD and vinyl recordings, but the RMS levels of the
vinyl recordings were 3-4 dB lower. So, the vinyl recordings actually had
a higher dynamic range than the CD recordings.

I suspected that when the songs were being re-mastered for release on CD,
the recording engineer was purposely introducing dynamic compression, since
that's becoming popular these days. As another experiment, I recorded a
fourth song from vinyl and CD, but this time I used an album that had just
released, so that I could be sure that the vinyl mastering and CD mastering
were both done recently. This time, both the peak and RMS levels matched
up almost exactly between the CD and vinyl recordings. So, the difference
in dynamic range for the other three songs had nothing to do with the media
(CD vs. vinyl), but was instead due wholly to the preferences of the
recording engineer.

Scott Gardner

Yep, that's the increase I was talking about. If an amplifer can produce
400W without any clipping (a sine wave with an amplitude exactly equal to
the rail voltage), then it can theoretically produce twice that much power
if it's driven to hard clipping (a square wave output with an amplitude
equal to the rail voltage).

no?!?!?!?! Clipping means the output has clipped at a certain voltage, it
does not produce more voltage, it clips!!!!

Yep, that's the increase I was talking about. If an amplifer can
produce
400W without any clipping (a sine wave with an amplitude exactly equal
to
the rail voltage), then it can theoretically produce twice that much
power
if it's driven to hard clipping (a square wave output with an amplitude
equal to the rail voltage).

no?!?!?!?! Clipping means the output has clipped at a certain voltage, it
does not produce more voltage, it clips!!!!

He didn't SAY it produces more voltage. He said it produces more power.

He said MORE POWER! Not more voltage...

A clipped signal IN FACT, IS more power than a non clipped
signal of the same voltage....

This is because the clipped signal has more at the top and bottom of the wave
and
less in the middle compared to a normal uncliped sine wave.

Eddie Runner
http://www.teamrocs.com

Scott Johnson wrote:

Yep, that's the increase I was talking about. If an amplifer can produce
400W without any clipping (a sine wave with an amplitude exactly equal to
the rail voltage), then it can theoretically produce twice that much power
if it's driven to hard clipping (a square wave output with an amplitude
equal to the rail voltage).

no?!?!?!?! Clipping means the output has clipped at a certain voltage, it
does not produce more voltage, it clips!!!!

man Mark,
you guys make it hard to get a word in edgewise nowdays....

ha ha ha

MZ wrote:

Yep, that's the increase I was talking about. If an amplifer can
produce
400W without any clipping (a sine wave with an amplitude exactly equal
to
the rail voltage), then it can theoretically produce twice that much
power
if it's driven to hard clipping (a square wave output with an amplitude
equal to the rail voltage).

no?!?!?!?! Clipping means the output has clipped at a certain voltage, it
does not produce more voltage, it clips!!!!

He didn't SAY it produces more voltage. He said it produces more power.