Hi there,

I just bought a Jensen KA3 3 Channel 450Watt amp and would like some
advice on hooking it up. I'm good with clean installs, but always fuzzy
on the numbers.

Front speakers are clarion SRR 1516's, rears are stock honda for now,
and massive audio single 10 in the trunk

Should I bridge both front and rear speakers through the 2 channels, or
just run front and leave rear on the deck? Also should I run the
single 10 at 2 ohms 4 bridged?

Thanks in advance,

Jeremy

In article . com,
"Jeremy" wrote:

Hi there,

I just bought a Jensen KA3 3 Channel 450Watt amp and would like some
advice on hooking it up. I'm good with clean installs, but always fuzzy
on the numbers.

Front speakers are clarion SRR 1516's, rears are stock honda for now,
and massive audio single 10 in the trunk

Should I bridge both front and rear speakers through the 2 channels, or
just run front and leave rear on the deck? Also should I run the
single 10 at 2 ohms 4 bridged?

Thanks in advance,

Jeremy

You'll have to do the math to balance out your power.

Honda stock speakers handle about 8 watts so I wouldn't bother amping
them. If you have a newer Honda, the rear speakers can literally be
crushed into a ball with bare hands. The front speakers aren't any
stronger but they're fiberglass so they'd shatter and cut you.

"Jeremy" wrote in message
ups.com...
Hi there,

I just bought a Jensen KA3 3 Channel 450Watt amp and would like some
advice on hooking it up. I'm good with clean installs, but always fuzzy
on the numbers.

Front speakers are clarion SRR 1516's, rears are stock honda for now,
and massive audio single 10 in the trunk

Should I bridge both front and rear speakers through the 2 channels, or
just run front and leave rear on the deck?

First, I would run the first two channels of the amp into the two front
speakers and not bridge them to all four. Let your deck power the rear
speakers. This usually works best as your fronts should be MUCH louder than
your rear speakers (or your "rear-fill" as they are called). Like a live
concert, the sound should seem to emanate IN FRONT of you, not from behind
you. With a subwoofer, however, this is not a problem as bass frequencies
are much more difficult to localize and therefore we can get away with
having our subwoofers in the rear of the car. Your rear-fill should add a
fullness to the sound, but you should not be able to tell that the sound is
coming from behind you. Your HU (head-unit) should produce enough power to
handle this. Also, if you WERE to bridge all four speakers to the two amp
channels, you would lose fader control, which would suck (of course, there
are ways around this using L-pads, but this gets very complicated).

Also should I run the
single 10 at 2 ohms 4 bridged?


I'm sorry, I really don't understand what you're asking. It appears the KA3
has three channels and the ohms the amp will see will depend on the speaker
you are driving. You cannot control that, unless it is a duel voice coil,
is that the case? If so (is it a dual 4 ohm VC?), then you can either run
it at a 2 ohm load or an 8 ohm load. I would DEFINITELY run it at a 2 ohm
load (run both VC's in parallel to the third amp channel) as that would
produce more power. Though, again, I'm not sure that's what you're asking.

BTW, I tried to do some research on that amp (the Jensen KA3) but the specs
appear a little odd on every page I find it described, here's an example
(obviously the picture won't come through and the fonts may be all messed up
as well):
Read product information for the Jensen KA3 Car Audio Amplifier The Jensen
KA3 has 100 Equalizer Bands. Signal to Noise Ratio: 100 Decibels. Read
reviews (5)
See product details
Save it to your list
Already own this product?
Write a review


Product Details
Key Features
Amplifier Type Dual Channel

RMS Power at 4 Ohms .4 W x 100 HUH?

RMS Power at 2 Ohms 1 W x 100 What?
Performance
Signal to Noise Ratio 100 dB

THD at Rated RMS Power 250% (this SUCKS!)
Crossover / Equalizer
Bass Boost Frequency 50 Hz

High - Pass Frequency 100 Hz - 20 Hz



These are VERY weird specs. 250% distortion? .4 W X 100? And these
specifications appear to be on ALL descriptions on all websites I visited.
I'm a little confused what this amp can actually do, but I THINK it is
capable of 100 watts X 2 + 250 X 1.

Hope this all helps.

MOSFET

Yeah these stock speakers are pretty nasty little fellas.. I wish I had
a bit more cash to spend on this project, but the honda rears will have
to do for now.

So.. the part I am confused about is running in 4ohm vs 2..

These are the specs for the KA3
* 4 ohm 2x100 *watts* peak 2x50 *watts* RMS .04% THD
* 4 ohm 250 *watts* peak 125 *watts* RMS.1% THD
* 2 ohm 400 *watts* peak 200 *watts* RMS
* 1 ohm 500 *watts* peak 250 *watts* RMS

What are the advantages and disadvantages of running 2 ohms vs 4?

Sorry about the stupid question, thanks for the help. J

"Jeremy" wrote in message
ups.com...
Yeah these stock speakers are pretty nasty little fellas.. I wish I had
a bit more cash to spend on this project, but the honda rears will have
to do for now.

So.. the part I am confused about is running in 4ohm vs 2..

These are the specs for the KA3
* 4 ohm 2x100 *watts* peak 2x50 *watts* RMS .04% THD
* 4 ohm 250 *watts* peak 125 *watts* RMS.1% THD
* 2 ohm 400 *watts* peak 200 *watts* RMS
* 1 ohm 500 *watts* peak 250 *watts* RMS

What are the advantages and disadvantages of running 2 ohms vs 4?

Sorry about the stupid question, thanks for the help. J

Perhaps you didn't read my previous post very carefully. The ohms depends
on what speakers you are using (it is NOT some switch or something on the
amp). If you are using a 2 ohm speaker, your amp will be running at 2 ohms,
if you are running a 4 ohm speaker, it will be running at 4 ohms. Ohms
represent the electrical resistance your amplifier outputs "see". A lower
ohms rating represents lower resistance and therefore you will get more
power out of your amplifier. Obviously, at some point, too low a resistance
(one ohm for instance) will produce too much strain on your amp (and will
cause your amp to blow fuses or be damaged). Obviously, if you can run your
amp at 2 ohms your will get more power but this COMPLETELY depends on the
speakers you are using.

MOSFET

In article , "MOSFET" wrote:

"Jeremy" wrote in message
oups.com...
Yeah these stock speakers are pretty nasty little fellas.. I wish I had
a bit more cash to spend on this project, but the honda rears will have
to do for now.

So.. the part I am confused about is running in 4ohm vs 2..

These are the specs for the KA3
* 4 ohm 2x100 *watts* peak 2x50 *watts* RMS .04% THD
* 4 ohm 250 *watts* peak 125 *watts* RMS.1% THD
* 2 ohm 400 *watts* peak 200 *watts* RMS
* 1 ohm 500 *watts* peak 250 *watts* RMS

What are the advantages and disadvantages of running 2 ohms vs 4?

Sorry about the stupid question, thanks for the help. J

Perhaps you didn't read my previous post very carefully. The ohms depends
on what speakers you are using (it is NOT some switch or something on the
amp). If you are using a 2 ohm speaker, your amp will be running at 2 ohms,
if you are running a 4 ohm speaker, it will be running at 4 ohms. Ohms
represent the electrical resistance your amplifier outputs "see". A lower
ohms rating represents lower resistance and therefore you will get more
power out of your amplifier. Obviously, at some point, too low a resistance
(one ohm for instance) will produce too much strain on your amp (and will
cause your amp to blow fuses or be damaged). Obviously, if you can run your
amp at 2 ohms your will get more power but this COMPLETELY depends on the
speakers you are using.

Among other things, they run hotter at low ohms, and is the main reason they
fail, because semiconductor ratings fall as they heat up. Fans can partially
remidy this. How about some freezing liquid. It might be neat to see the
steam falling beneith the car like a spaceship.

greg

These are the specs for the KA3
* 4 ohm 2x100 *watts* peak 2x50 *watts* RMS .04% THD
* 4 ohm 250 *watts* peak 125 *watts* RMS.1% THD
* 2 ohm 400 *watts* peak 200 *watts* RMS
* 1 ohm 500 *watts* peak 250 *watts* RMS

Also, these specs are a little confusing as well. The KA3 is a three
channel amp, right?

OK then, so we have 2 X 50 RMS (at 4 ohms) for the first two channels
(pretty straight forward so far). And then I assume we have 1 X 125 RMS (at
4 ohms) for the third channel, right (this is where it gets confusing)? And
it appears this third channel is 1 ohm stable, which is good (if you can
find a subwoofer or a combination of subwoofers that present a one ohm load,
this will give you LOTS of power obviously).

But it appears that there are no specs given for the first two channels at 2
ohms (so IS this amp even 2 ohm stable for channels 1 and 2). I would
imagine, however, that it is as this is pretty standard. This specification
would look something like this:

* 2 Ohms 2 X 200 *watts" peak 2 X 100 *watts* RMS .1% THD

But I don't see this there. It would help IMMENSELY if Jensen numbered
these channels when stating the specs.

MOSFET

OK, upon further research, the ACTUAL specs (from the CSR 2000 Buyer's
Guide) are as follows:

Channels 1 and 2: 2 x 50 watts RMS at 4 ohms, 2 X 100 watts RMS at 2 ohms
(channels 1 and 2 ARE NOT 1 ohm stable while channel 3 is)
Channel 3: 100 watts RMS at 4 ohms, 200 watts RMS at 2 ohms, 250 RMS at 1
ohm
It also has an 18 dB high/low X-over (nice feature). List price in 2000:
$279

MOSFET

"MOSFET" wrote in message
...
These are the specs for the KA3
* 4 ohm 2x100 *watts* peak 2x50 *watts* RMS .04% THD
* 4 ohm 250 *watts* peak 125 *watts* RMS.1% THD
* 2 ohm 400 *watts* peak 200 *watts* RMS
* 1 ohm 500 *watts* peak 250 *watts* RMS

Also, these specs are a little confusing as well. The KA3 is a three
channel amp, right?

OK then, so we have 2 X 50 RMS (at 4 ohms) for the first two channels
(pretty straight forward so far). And then I assume we have 1 X 125 RMS
(at 4 ohms) for the third channel, right (this is where it gets
confusing)? And it appears this third channel is 1 ohm stable, which is
good (if you can find a subwoofer or a combination of subwoofers that
present a one ohm load, this will give you LOTS of power obviously).

But it appears that there are no specs given for the first two channels at
2 ohms (so IS this amp even 2 ohm stable for channels 1 and 2). I would
imagine, however, that it is as this is pretty standard. This
specification would look something like this:

* 2 Ohms 2 X 200 *watts" peak 2 X 100 *watts* RMS .1% THD

But I don't see this there. It would help IMMENSELY if Jensen numbered
these channels when stating the specs.

MOSFET

Thanks Mosfet, nice digging for those numbers!

The Clarion front speakers are 35Watts continuous @ 4 Ohms, 160W peak

Not sure about Honda rears

Massive 10 inch Sub is dual voice coil, 200 watts RMS min, 400 watts
Max.

The Jensen looks a little short on the Sub channel. Would I damage it
my running it at 100 Watts?

Thanks for the advice..

GregS Wrote:
Among other things, they run hotter at low ohms, and is the main reason
they
fail, because semiconductor ratings fall as they heat up. Fans can
partially
remidy this. How about some freezing liquid. It might be neat to see
the
steam falling beneith the car like a spaceship. greg

Some amps can be water cooled, and you can stick a TEC in-line with the
water flow. What a TEC (thermo electric cooler) or peltier is, is a
cluster of transistors placed back to back, and wired together, so that
heat is sucked or "pumped" away from one side of the module (which is a
white square) and pushed out towards the other end. Although the module
serves to displace the heat by pumping it away from the source, the
"hot" side of the unit still has to be cooled, or it cannot get rid of
the heat that it has stored and thus cannot remove any more heat from
the source (in this case, water). I had a setup very similar to this in
my PC once upon a time, and got it down to zero degrees with a 75 watt
peltier unit. I was thinking of doing this with my PPI art that can be
water cooled, because I have all of this water cooling stuff sitting
around and not being used. But if you don't lower the specific heat of
the coolant, or water, you'll freeze it (so add Redline water wetter
for radiators). You'll need a small radiator, a water block, peltier,
12v supply, and a 12v water pump and tubing and a resevoir. In fact,
now that I think about it, this setup lends itself perfectly to cars
because it's not a really big deal if you spill a little water in your
car, as it would be inside a computer (which is what happened to my PC
when the cheap pump burst). You also don't have to worry too much about
condensation with an in-line TEC as you would with one that sits right
on a PC processor. I think I'm gonna do that. Certainly the worlds of
PC modding and audio installs are very similar in terms of aesthetics
any how.
Chris


--
flak_monkey

Sorry.. what I meant to say was would I damage the sub by only giving
it 100 Watts?

Thanks in advance, Jeremy

Jeremy Wrote:
Sorry.. what I meant to say was would I damage the sub by only giving
it 100 Watts?

Thanks in advance, Jeremy

The only reason underpowering a sub is ever bad is because people
typicaly want more output than an under powered amp can provide. At
this point people will crank up the bass boost, gain, etc., to extract
more output; which can cause clipping. This is where the underpowering
part becomes bad.

If it supplies enough output for you, then no harm, no foul. If not,
you will have to go with a bigger amp to pick up the extra volume.


--
danssoslow

I'm afraid I have to disagree with what danssoslow said. Although he is
right in that driving your amp too hard will cause clipping, that IS NOT
dangerous or bad for your speaker. So this simple answer, is no, you won't
damage your sub by underpowering it.

A little about clipping... Sound is produced electrically as a waveform.
When you begin to run out of power, your amp begins to cut off, or "clip"
the top and bottom portion of this waveform. In other words, when your amp
tries to play a REALLY loud part, it will run out of gas and everything will
begin to sound at the same decibel level. But this will not damage a
speaker, because to a speaker, this is simply what it thinks it's supposed
to be playing. It may sound terrible to us, but to the speaker, it's just
reproducing the waveform that it is being fed, and as long as the power does
not exceed the speaker's rating, everything's fine. This is actually a very
common debate topic in audio circles (can you damage a speaker by
UNDERPOWERING it?), and the simple answer is no, you cannot (OK, this is
Usenet so some wise-apple will probably craft some outlandish scenario where
by playing a continuous test-tone for 50 hours a voice-coil will eventually
melt, just to prove me wrong, but under NORMAL circumstances underpowering a
speaker will not damage it) . What WILL damage a speaker is producing an
electrical waveform that exceeds the physical excursion limits of the driver
(with too much power). Too much power will also produce a build up of heat
in the voice-coil that can also damage a speaker.

If your subwoofer is a dual voice coil, then I would CERTAINLY wire both
coils in parallel to produce the lowest impedance (if it is a dual 4 ohm
voice coil sub, then the amp will see a 2 ohm load) and this will extract
the most power from your amplifier. If you had two of those subs, you could
wire ALL FOUR of the voice coils (two per sub) in parallel to produce a 1
ohm load, which your Jensen apparently CAN handle. This would extract the
maximum power from your amp. But again, DON'T WORRY about underpowering
your subwoofer.

MOSFET

"Jeremy" wrote in message
oups.com...
Sorry.. what I meant to say was would I damage the sub by only giving
it 100 Watts?

Thanks in advance, Jeremy

MOSFET wrote:
(can you damage a speaker by
UNDERPOWERING it?), and the simple answer is no, you cannot (OK, this is
Usenet so some wise-apple will probably craft some outlandish scenario where
by playing a continuous test-tone for 50 hours a voice-coil will eventually
melt, just to prove me wrong, but under NORMAL circumstances underpowering a
speaker will not damage it) .

MOSFET, I didnt understand what you just said... forgive me... How
would the voice-coil melt if its underpowered.. even if its played for
blah...blah... .... i mean, the speaker is capable of handling the MAX
load it is rated at right?
And one more thing, how did the idea came up that "underpowering the
speaker" would spoil it?... could anyone please throw more light into
it?

Do bear with me for asking such silly question....

Regards,
Antony.

I have actually heard this from car audio sales people. And I'm sure there
are STILL many out there who believe this. They think that a heavily
clipped (distorted) signal will somehow damage a speaker, and therefore, for
this reason it is dangerous to underpower a speaker. Trust me, MANY people
still think this. It didn't help that for years speaker manufacturers used
to give MINIMUM power ratings (some still do!) as well as maximum ratings
for their speakers (again, this implied that it might be wrong to go below
this minimum).

As far as my scenario, I really don't know if there's any way underpowering
a speaker can actually damage it, but I know the guys on this group LOVE to
find contradictions so I just thought of the first thing that popped into my
head (I have no idea if this will damage a speaker at all).

MOSFET

"anToNIcHeN" wrote in message
oups.com...

MOSFET wrote:
(can you damage a speaker by
UNDERPOWERING it?), and the simple answer is no, you cannot (OK, this is
Usenet so some wise-apple will probably craft some outlandish scenario
where
by playing a continuous test-tone for 50 hours a voice-coil will
eventually
melt, just to prove me wrong, but under NORMAL circumstances
underpowering a
speaker will not damage it) .

MOSFET, I didnt understand what you just said... forgive me... How
would the voice-coil melt if its underpowered.. even if its played for
blah...blah... .... i mean, the speaker is capable of handling the MAX
load it is rated at right?
And one more thing, how did the idea came up that "underpowering the
speaker" would spoil it?... could anyone please throw more light into
it?

Do bear with me for asking such silly question....

Regards,
Antony.

a clipped signal will put out more power than an unclipped signal, and
this is how underpowered speakers blow. a 500 watt amp could put out
7-800 watts if clipped hard, which could blow a rated 600 watt
subwoofer even though the amp's RMS rating is below the speaker's. a
square (hard clipped) wave has more area under the curve than a normal
sine wave, and the area under the curve represents power.



and you can blow a speaker mechanically by playing under it's tune in a
ported box with significantly less power than the speaker is rated for,
but that's a different discussion.


--
KU40

I feel I have enough information for proceed with the install. Thanks
to everyone for your help, I look forward to some good sounding music
ahead!

Cheers, Jeremy

The amount of energy in a fully clipped square wave from an amp
approaches 2x the amount of power it produces just before the onset of
clipping. That's a ton more power applied to the speaker's voice coil &
can certainly exceed either the instantaneous or long-term thermal limits.

If you connect a 50 watt amp to a speaker with an honestly rated (EIAA
thermal 24hr tested) 50 watt speaker speaker and then clip it as hard as
possible, you'll kill it. If the amp is only 35 watts and you do the
same thing to the same 50 watt speaker, you'll kill it - the clipped
output at close to 70 watts will be above the 50 watt thermal limit.

Of course, there are a gazillion variables in how companies rate their
speaker power handling, from very conservative to something of a joke in
the opposite direction and those variables can wreck this "laboratory"
conclusion very quickly.

JD

MOSFET wrote:

I'm afraid I have to disagree with what danssoslow said. Although he is
right in that driving your amp too hard will cause clipping, that IS NOT
dangerous or bad for your speaker. So this simple answer, is no, you won't
damage your sub by underpowering it.

A little about clipping... Sound is produced electrically as a waveform.
When you begin to run out of power, your amp begins to cut off, or "clip"
the top and bottom portion of this waveform. In other words, when your amp
tries to play a REALLY loud part, it will run out of gas and everything will
begin to sound at the same decibel level. But this will not damage a
speaker, because to a speaker, this is simply what it thinks it's supposed
to be playing. It may sound terrible to us, but to the speaker, it's just
reproducing the waveform that it is being fed, and as long as the power does
not exceed the speaker's rating, everything's fine. This is actually a very
common debate topic in audio circles (can you damage a speaker by
UNDERPOWERING it?), and the simple answer is no, you cannot (OK, this is
Usenet so some wise-apple will probably craft some outlandish scenario where
by playing a continuous test-tone for 50 hours a voice-coil will eventually
melt, just to prove me wrong, but under NORMAL circumstances underpowering a
speaker will not damage it) . What WILL damage a speaker is producing an
electrical waveform that exceeds the physical excursion limits of the driver
(with too much power). Too much power will also produce a build up of heat
in the voice-coil that can also damage a speaker.

If your subwoofer is a dual voice coil, then I would CERTAINLY wire both
coils in parallel to produce the lowest impedance (if it is a dual 4 ohm
voice coil sub, then the amp will see a 2 ohm load) and this will extract
the most power from your amplifier. If you had two of those subs, you could
wire ALL FOUR of the voice coils (two per sub) in parallel to produce a 1
ohm load, which your Jensen apparently CAN handle. This would extract the
maximum power from your amp. But again, DON'T WORRY about underpowering
your subwoofer.

MOSFET

"Jeremy" wrote in message
oups.com...

Sorry.. what I meant to say was would I damage the sub by only giving
it 100 Watts?

Thanks in advance, Jeremy

Forgive me as I not electrical engineer, but I think what you are saying is
that an amp rated at 50 watts will produce significantly more power when
pushed heavily into distortion. This is why power ratings are often given
as 50 (let's say) watts RMS at .01% THD, 200 watts max (this max number may
represent 100% distortion).

If this is the point you are trying to make, then yes, I had not considered
this.

BUT, this still does not truly answer the question of whether an
underpowered amp can destroy a speaker because in the example I gave above,
if we are talking about a 50 watt speaker and it receives 200 watts of
distorted signal, this is certainly not "underpowering". I guess the
dilemma here is would someone really listen to a heavily distorted signal?
And when discussing this issue do we need to refer to MAXIMUM power, or
rated power?

But again, I see your point. Frankly, I'm afraid you were EXACTLY the kind
of "wise-apple" I was expecting when I posted my response. However, in the
"real world", as long as you don't push your amp into clipping, I think it
is generally safe to say that there are no problems with a 20 watt rated amp
(for example) driving a 100 watt speaker. That was REALLY my only point.

MOSFET


"John Durbin" wrote in message
...
The amount of energy in a fully clipped square wave from an amp approaches
2x the amount of power it produces just before the onset of clipping.
That's a ton more power applied to the speaker's voice coil & can
certainly exceed either the instantaneous or long-term thermal limits.

If you connect a 50 watt amp to a speaker with an honestly rated (EIAA
thermal 24hr tested) 50 watt speaker speaker and then clip it as hard as
possible, you'll kill it. If the amp is only 35 watts and you do the same
thing to the same 50 watt speaker, you'll kill it - the clipped output at
close to 70 watts will be above the 50 watt thermal limit.

Of course, there are a gazillion variables in how companies rate their
speaker power handling, from very conservative to something of a joke in
the opposite direction and those variables can wreck this "laboratory"
conclusion very quickly.

JD

MOSFET wrote:

I'm afraid I have to disagree with what danssoslow said. Although he is
right in that driving your amp too hard will cause clipping, that IS NOT
dangerous or bad for your speaker. So this simple answer, is no, you
won't damage your sub by underpowering it.

A little about clipping... Sound is produced electrically as a waveform.
When you begin to run out of power, your amp begins to cut off, or "clip"
the top and bottom portion of this waveform. In other words, when your
amp tries to play a REALLY loud part, it will run out of gas and
everything will begin to sound at the same decibel level. But this will
not damage a speaker, because to a speaker, this is simply what it thinks
it's supposed to be playing. It may sound terrible to us, but to the
speaker, it's just reproducing the waveform that it is being fed, and as
long as the power does not exceed the speaker's rating, everything's
fine. This is actually a very common debate topic in audio circles (can
you damage a speaker by UNDERPOWERING it?), and the simple answer is no,
you cannot (OK, this is Usenet so some wise-apple will probably craft
some outlandish scenario where by playing a continuous test-tone for 50
hours a voice-coil will eventually melt, just to prove me wrong, but
under NORMAL circumstances underpowering a speaker will not damage it) .
What WILL damage a speaker is producing an electrical waveform that
exceeds the physical excursion limits of the driver (with too much
power). Too much power will also produce a build up of heat in the
voice-coil that can also damage a speaker.

If your subwoofer is a dual voice coil, then I would CERTAINLY wire both
coils in parallel to produce the lowest impedance (if it is a dual 4 ohm
voice coil sub, then the amp will see a 2 ohm load) and this will extract
the most power from your amplifier. If you had two of those subs, you
could wire ALL FOUR of the voice coils (two per sub) in parallel to
produce a 1 ohm load, which your Jensen apparently CAN handle. This
would extract the maximum power from your amp. But again, DON'T WORRY
about underpowering your subwoofer.

MOSFET

"Jeremy" wrote in message
oups.com...

Sorry.. what I meant to say was would I damage the sub by only giving
it 100 Watts?

Thanks in advance, Jeremy

You are correct in saying that distortion kills the speaker, but the
question here is whether underpowering the sub kills it or not. The answer
to this is definately No. How do you assume that the underpowered amp has
distortion and a matched powered amp doesn't. If you say that the distortion
is inversely proportional to the wattage and price of the amp then that is a
completely different question.

I think you are confusion distortion with under powering!

"John Durbin" wrote in message
...
| The amount of energy in a fully clipped square wave from an amp
| approaches 2x the amount of power it produces just before the onset of
| clipping. That's a ton more power applied to the speaker's voice coil &
| can certainly exceed either the instantaneous or long-term thermal limits.
|
| If you connect a 50 watt amp to a speaker with an honestly rated (EIAA
| thermal 24hr tested) 50 watt speaker speaker and then clip it as hard as
| possible, you'll kill it. If the amp is only 35 watts and you do the
| same thing to the same 50 watt speaker, you'll kill it - the clipped
| output at close to 70 watts will be above the 50 watt thermal limit.
|
| Of course, there are a gazillion variables in how companies rate their
| speaker power handling, from very conservative to something of a joke in
| the opposite direction and those variables can wreck this "laboratory"
| conclusion very quickly.
|
| JD
|
| MOSFET wrote:
|
| I'm afraid I have to disagree with what danssoslow said. Although he is
| right in that driving your amp too hard will cause clipping, that IS NOT
| dangerous or bad for your speaker. So this simple answer, is no, you
won't
| damage your sub by underpowering it.
|
| A little about clipping... Sound is produced electrically as a
waveform.
| When you begin to run out of power, your amp begins to cut off, or
"clip"
| the top and bottom portion of this waveform. In other words, when your
amp
| tries to play a REALLY loud part, it will run out of gas and everything
will
| begin to sound at the same decibel level. But this will not damage a
| speaker, because to a speaker, this is simply what it thinks it's
supposed
| to be playing. It may sound terrible to us, but to the speaker, it's
just
| reproducing the waveform that it is being fed, and as long as the power
does
| not exceed the speaker's rating, everything's fine. This is actually a
very
| common debate topic in audio circles (can you damage a speaker by
| UNDERPOWERING it?), and the simple answer is no, you cannot (OK, this is
| Usenet so some wise-apple will probably craft some outlandish scenario
where
| by playing a continuous test-tone for 50 hours a voice-coil will
eventually
| melt, just to prove me wrong, but under NORMAL circumstances
underpowering a
| speaker will not damage it) . What WILL damage a speaker is producing
an
| electrical waveform that exceeds the physical excursion limits of the
driver
| (with too much power). Too much power will also produce a build up of
heat
| in the voice-coil that can also damage a speaker.
|
| If your subwoofer is a dual voice coil, then I would CERTAINLY wire both
| coils in parallel to produce the lowest impedance (if it is a dual 4 ohm
| voice coil sub, then the amp will see a 2 ohm load) and this will
extract
| the most power from your amplifier. If you had two of those subs, you
could
| wire ALL FOUR of the voice coils (two per sub) in parallel to produce a
1
| ohm load, which your Jensen apparently CAN handle. This would extract
the
| maximum power from your amp. But again, DON'T WORRY about underpowering
| your subwoofer.
|
| MOSFET
|
| "Jeremy" wrote in message
| oups.com...
|
| Sorry.. what I meant to say was would I damage the sub by only giving
| it 100 Watts?
|
| Thanks in advance, Jeremy
|
|
|
|
|

again, distortion does not kill the speaker. As has been said, the
speaker doesn't know that the signal it's getting is distorted. You
can send it an absolute square wave with nearly 100% distortion and it
won't matter as long as the power is still something the speaker can
handle. Think of guitarists. They can turn the distortion way up to
get different sounds during their concerts, but they don't blow any
speakers.

Only power is involved in a melted voice coil.

and I'll also agree that it depends on how well a manufacturer rates
their speakers as to if they'll blow with the true RMS rating applied.
Most of the good companies will use the standard set by the size of the
voice coil. The only one I've ever heard a story about is JL, who I
read rates their speakers by applying the RMS for 24 hours straight and
if the woofer lives, that's the rating.


--
KU40

In the "real world", we assume end users ALWAYS drive their amps into
clipping :-)

JD
subwoofer return rates certainly support that conclusion

MOSFET wrote:
Forgive me as I not electrical engineer, but I think what you are saying is
that an amp rated at 50 watts will produce significantly more power when
pushed heavily into distortion. This is why power ratings are often given
as 50 (let's say) watts RMS at .01% THD, 200 watts max (this max number may
represent 100% distortion).

If this is the point you are trying to make, then yes, I had not considered
this.

BUT, this still does not truly answer the question of whether an
underpowered amp can destroy a speaker because in the example I gave above,
if we are talking about a 50 watt speaker and it receives 200 watts of
distorted signal, this is certainly not "underpowering". I guess the
dilemma here is would someone really listen to a heavily distorted signal?
And when discussing this issue do we need to refer to MAXIMUM power, or
rated power?

But again, I see your point. Frankly, I'm afraid you were EXACTLY the kind
of "wise-apple" I was expecting when I posted my response. However, in the
"real world", as long as you don't push your amp into clipping, I think it
is generally safe to say that there are no problems with a 20 watt rated amp
(for example) driving a 100 watt speaker. That was REALLY my only point.

MOSFET


"John Durbin" wrote in message
...

The amount of energy in a fully clipped square wave from an amp approaches
2x the amount of power it produces just before the onset of clipping.
That's a ton more power applied to the speaker's voice coil & can
certainly exceed either the instantaneous or long-term thermal limits.

If you connect a 50 watt amp to a speaker with an honestly rated (EIAA
thermal 24hr tested) 50 watt speaker speaker and then clip it as hard as
possible, you'll kill it. If the amp is only 35 watts and you do the same
thing to the same 50 watt speaker, you'll kill it - the clipped output at
close to 70 watts will be above the 50 watt thermal limit.

Of course, there are a gazillion variables in how companies rate their
speaker power handling, from very conservative to something of a joke in
the opposite direction and those variables can wreck this "laboratory"
conclusion very quickly.

JD

MOSFET wrote:


I'm afraid I have to disagree with what danssoslow said. Although he is
right in that driving your amp too hard will cause clipping, that IS NOT
dangerous or bad for your speaker. So this simple answer, is no, you
won't damage your sub by underpowering it.

A little about clipping... Sound is produced electrically as a waveform.
When you begin to run out of power, your amp begins to cut off, or "clip"
the top and bottom portion of this waveform. In other words, when your
amp tries to play a REALLY loud part, it will run out of gas and
everything will begin to sound at the same decibel level. But this will
not damage a speaker, because to a speaker, this is simply what it thinks
it's supposed to be playing. It may sound terrible to us, but to the
speaker, it's just reproducing the waveform that it is being fed, and as
long as the power does not exceed the speaker's rating, everything's
fine. This is actually a very common debate topic in audio circles (can
you damage a speaker by UNDERPOWERING it?), and the simple answer is no,
you cannot (OK, this is Usenet so some wise-apple will probably craft
some outlandish scenario where by playing a continuous test-tone for 50
hours a voice-coil will eventually melt, just to prove me wrong, but
under NORMAL circumstances underpowering a speaker will not damage it) .
What WILL damage a speaker is producing an electrical waveform that
exceeds the physical excursion limits of the driver (with too much
power). Too much power will also produce a build up of heat in the
voice-coil that can also damage a speaker.

If your subwoofer is a dual voice coil, then I would CERTAINLY wire both
coils in parallel to produce the lowest impedance (if it is a dual 4 ohm
voice coil sub, then the amp will see a 2 ohm load) and this will extract
the most power from your amplifier. If you had two of those subs, you
could wire ALL FOUR of the voice coils (two per sub) in parallel to
produce a 1 ohm load, which your Jensen apparently CAN handle. This
would extract the maximum power from your amp. But again, DON'T WORRY
about underpowering your subwoofer.

MOSFET

"Jeremy" wrote in message
egroups.com...


Sorry.. what I meant to say was would I damage the sub by only giving
it 100 Watts?

Thanks in advance, Jeremy

In the "real world", we assume end users ALWAYS drive their amps into
clipping :-)

LOL

Yes, you're right.

No, I'm not. In fact, I absolutely did NOT say that distortion killed
anything. I said that clipping the amp makes it produce a lot more power
than its unclipped rating.

So, when consumer Joe buys an amp rated at 100 watts RMS and connects it
to a sub rated at say 150 watts, he assumes he can't hurt the sub. Or,
the dealer that sold it to him may assume that or sell the combination
that way. By definition, this would be - based on RMS ratings -
underpowering.

In fact, the 100 watt amp can be clipped hard to produce almost 200
watts which will eventually destroy the voice coil of the 150 watt sub,
if that 150 watt rating is an accurate one.

What's more common is that the subwoofer rating is not an honest EIAA
thermal cycle-based rating, and the voice coil can fail at lower power
limits. That moves it even closer to damage in the example above.

JD

Vivek wrote:

You are correct in saying that distortion kills the speaker, but the
question here is whether underpowering the sub kills it or not. The answer
to this is definately No. How do you assume that the underpowered amp has
distortion and a matched powered amp doesn't. If you say that the distortion
is inversely proportional to the wattage and price of the amp then that is a
completely different question.

I think you are confusion distortion with under powering!

"John Durbin" wrote in message
...
| The amount of energy in a fully clipped square wave from an amp
| approaches 2x the amount of power it produces just before the onset of
| clipping. That's a ton more power applied to the speaker's voice coil &
| can certainly exceed either the instantaneous or long-term thermal limits.
|
| If you connect a 50 watt amp to a speaker with an honestly rated (EIAA
| thermal 24hr tested) 50 watt speaker speaker and then clip it as hard as
| possible, you'll kill it. If the amp is only 35 watts and you do the
| same thing to the same 50 watt speaker, you'll kill it - the clipped
| output at close to 70 watts will be above the 50 watt thermal limit.
|
| Of course, there are a gazillion variables in how companies rate their
| speaker power handling, from very conservative to something of a joke in
| the opposite direction and those variables can wreck this "laboratory"
| conclusion very quickly.
|
| JD
|
| MOSFET wrote:
|
| I'm afraid I have to disagree with what danssoslow said. Although he is
| right in that driving your amp too hard will cause clipping, that IS NOT
| dangerous or bad for your speaker. So this simple answer, is no, you
won't
| damage your sub by underpowering it.
|
| A little about clipping... Sound is produced electrically as a
waveform.
| When you begin to run out of power, your amp begins to cut off, or
"clip"
| the top and bottom portion of this waveform. In other words, when your
amp
| tries to play a REALLY loud part, it will run out of gas and everything
will
| begin to sound at the same decibel level. But this will not damage a
| speaker, because to a speaker, this is simply what it thinks it's
supposed
| to be playing. It may sound terrible to us, but to the speaker, it's
just
| reproducing the waveform that it is being fed, and as long as the power
does
| not exceed the speaker's rating, everything's fine. This is actually a
very
| common debate topic in audio circles (can you damage a speaker by
| UNDERPOWERING it?), and the simple answer is no, you cannot (OK, this is
| Usenet so some wise-apple will probably craft some outlandish scenario
where
| by playing a continuous test-tone for 50 hours a voice-coil will
eventually
| melt, just to prove me wrong, but under NORMAL circumstances
underpowering a
| speaker will not damage it) . What WILL damage a speaker is producing
an
| electrical waveform that exceeds the physical excursion limits of the
driver
| (with too much power). Too much power will also produce a build up of
heat
| in the voice-coil that can also damage a speaker.
|
| If your subwoofer is a dual voice coil, then I would CERTAINLY wire both
| coils in parallel to produce the lowest impedance (if it is a dual 4 ohm
| voice coil sub, then the amp will see a 2 ohm load) and this will
extract
| the most power from your amplifier. If you had two of those subs, you
could
| wire ALL FOUR of the voice coils (two per sub) in parallel to produce a
1
| ohm load, which your Jensen apparently CAN handle. This would extract
the
| maximum power from your amp. But again, DON'T WORRY about underpowering
| your subwoofer.
|
| MOSFET
|
| "Jeremy" wrote in message
| oups.com...
|
| Sorry.. what I meant to say was would I damage the sub by only giving
| it 100 Watts?
|
| Thanks in advance, Jeremy
|
|
|
|
|

EIAA has a standard power handling test based on 24hr survival where you
base the rating on the last power level that the driver survived for
24hrs. before it ultimately failed. We use a modified version for
subwoofer testing that runs at lower frequencies. In addition to that,
we provide vendors with a specific test CD and level requirements for
testing the limits of mechanical survivability.

Size of voice coil is not in and of itself enough to set the rating.
There are huge variations on the thermal limits of the glue chosen to
secure the voice coil, and in forced air or other coil cooling methods
that can cause huge variations on power handling. A 3" coil with low
temp glues and no cooling support in the design can fail faster and at
lower temp than a 2.5" coil with good ventilation and quality glue.

JD

KU40 wrote:

again, distortion does not kill the speaker. As has been said, the
speaker doesn't know that the signal it's getting is distorted. You
can send it an absolute square wave with nearly 100% distortion and it
won't matter as long as the power is still something the speaker can
handle. Think of guitarists. They can turn the distortion way up to
get different sounds during their concerts, but they don't blow any
speakers.

Only power is involved in a melted voice coil.

and I'll also agree that it depends on how well a manufacturer rates
their speakers as to if they'll blow with the true RMS rating applied.
Most of the good companies will use the standard set by the size of the
voice coil. The only one I've ever heard a story about is JL, who I
read rates their speakers by applying the RMS for 24 hours straight and
if the woofer lives, that's the rating.

No, I'm not. In fact, I absolutely did NOT say that distortion killed
anything. I said that clipping the amp makes it produce a lot more power
than its unclipped rating.

Yes, in fact I think when people ask about underpowering a speaker and if
this is dangerous as the OP did, I think what they more often mean to ask is
"is DISTORTION dangerous to a speaker?". And the answer is no. To the
speaker, it is simply the sound it is being asked to reproduce.

BUT, distortion often indicates that an amp is producing more than it's
rated (undistorted) power. And THIS (too much power) can hurt a speaker.

MOSFET

MOSFET Wrote:
No, I'm not. In fact, I absolutely did NOT say that distortion killed
anything. I said that clipping the amp makes it produce a lot more
power
than its unclipped rating.

Yes, in fact I think when people ask about underpowering a speaker and
if
this is dangerous as the OP did, I think what they more often mean to
ask is
"is DISTORTION dangerous to a speaker?". And the answer is no. To the
speaker, it is simply the sound it is being asked to reproduce.

BUT, distortion often indicates that an amp is producing more than it's
rated (undistorted) power. And THIS (too much power) can hurt a
speaker.

MOSFET

So what exactly do not agree with me about? The word distortion was
never even mention in my post.


--
danssoslow

So what exactly do not agree with me about? The word distortion was
never even mention in my post.

Clipping IS a form of distortion. Your post seemed to indicate that
CLIPPING was dangerous. As we've already discussed, clipping IS NOT
dangerous (the speaker does not know it's reproducing a clipped signal) as
long as it does not exceed the power rating of the speaker.

MOSFET