10% THD?

[Eeyore]

BobG wrote:

On Apr 9, 8:49�pm, "Phil Allison" <philalli...@tpg.com.au> wrote:
** Hey Bob,

take a breath - �you are not talking about the same topic as others here !!
==============================================
I claimed that one cannot see 3% distortion in a sine wave on a scope.

And the only 3% distortion you'll see from a modern solid state amplifier is
CLIPPING distortion.

Graham

 

On Apr 9, 8:40 pm, gerf...@gmail.com wrote:

On Apr 8, 10:16 pm, mrdarr...@gmail.com wrote:



On Apr 8, 9:58 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com
wrote:

BobG wrote:
But 'visible clipping' is
about 10%, and is surprisingly inaudible.

Absolute nonsense. You can easily see clipping on a sinewave on a scope at
less than 1% and it's CLEARLY audible due to the high harmonic content.

Graham

Perhaps you have better ears than the rest of us. ;-)

There's a cellphone ringtone that supposedly only teenagers can hear,
no one over thirty - so if they get a call, their parents/teachers are
none the wiser.

Michael

How would that be possible?

Adam
Do something good today. Fight cancer with just a click! - Global
Cancer Research Institutehttp://gcri.blogspot.com/

http://www.freemosquitoringtones.org/

 

On Apr 9, 8:40 pm, gerf...@gmail.com wrote:

On Apr 8, 10:16 pm, mrdarr...@gmail.com wrote:



On Apr 8, 9:58 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com
wrote:

BobG wrote:
But 'visible clipping' is
about 10%, and is surprisingly inaudible.

Absolute nonsense. You can easily see clipping on a sinewave on a scope at
less than 1% and it's CLEARLY audible due to the high harmonic content.

Graham

Perhaps you have better ears than the rest of us. ;-)

There's a cellphone ringtone that supposedly only teenagers can hear,
no one over thirty - so if they get a call, their parents/teachers are
none the wiser.

Michael

How would that be possible?

Adam
Do something good today. Fight cancer with just a click! - Global
Cancer Research Institutehttp://gcri.blogspot.com/

.... and this
http://saunderslog.com/2006/06/12/the-mosquito-ring-tone-this-adult-can-hear-it/

 

[Eeyore]

Bob Eld wrote:

Well, maybe I should change it to nobody in their right mind would BUY such
a lousy amplifier. You certainly can do better than 10%THD but at what
price, I don't know. This thing might fit your needs if sound quality is not
a big issue.

I think you're missing the point.

I have little doubt that this amplifier is capable of 0.1% THD at say 60W.

The 10% THD figure has simply been used in order to produce an inflated power
rating. This is considered normal practice with car audio.

Graham

 

On Apr 10, 12:43 pm, "Bob Eld" <nsmontas...@yahoo.com> wrote:

"Eeyore" <rabbitsfriendsandrelati...@hotmail.com> wrote in message

news:47FE3D59.1A895B20@hotmail.com...





Bob Eld wrote:

Well, maybe I should change it to nobody in their right mind would BUY
such
a lousy amplifier. You certainly can do better than 10%THD but at what
price, I don't know. This thing might fit your needs if sound quality is
not
a big issue.

I think you're missing the point.

I have little doubt that this amplifier is capable of 0.1% THD at say 60W.

The 10% THD figure has simply been used in order to produce an inflated
power
rating. This is considered normal practice with car audio.

Graham

Yep, apparently that must be the case. However, this isn't car audio. Here's
the device:http://av.jvc.com/product.jsp?modelId=MODL027647&pathId=5&page=2

Also, can this POS deliver 100 Watts of its distorted power on all five of
it's channels simultaneously? I'll bet not. The rating must be one channel
at a time run for just the few seconds it takes to get a measurement and no
longer.

IIRC, the mannual says the power supply consumes 155W, 200VA.

I'm guessing the power supply won't appreciate being driven on all 5
channels with subwoofers.

Don't you love it when a device is spec'ed at 500W output, with less
than 200W input. I explained it to my wife this way: how can a
business collect only $200 a day, but spend $500 a day, and stay
afloat?

But this isn't unique to JVC. Sherwood's unit does something
similar. (Power cable says 200W, and it's rated at 500W or more.)

Which is why, I guess, if I want 500W per channel, I'd better build
the darn thing myself. ;-)

Michael

 

[NewsGroups]

<mrdarrett@gmail.com> wrote in message
news:8b5083e5-4d3e-4117-86d6-a3213396f804@s39g2000prd.googlegroups.com...

Are they serious?

http://av.jvc.com/product.jsp?modelId=MODL027647&pathId=5&page=2
"100 watts per channel, 8 ohms at 1kHz, with 10% THD"

10% THD sounds like a lot.

This is actually VERY good compared to most car stereo boom
things.

Michael

 

[BobG]

Yo Phil.... theoretical question.... I have two hi quality sine
generators and a THD meter. If I set generator 1 at 1V 1KHz and
generator 2 at .03V 3khz, thats the only 'distortion component', 3rd
harmonic thats 3% of the fundamental. I guess I could square it and
sqrt it, but since thats the only harmonic, would it show 3% THD on
the meter? Thanks.

 

[z]

On Apr 8, 11:35 pm, mrdarr...@gmail.com wrote:

Are they serious?

http://av.jvc.com/product.jsp?modelId=MODL027647&pathId=5&page=2
"100 watts per channel, 8 ohms at 1kHz, with 10% THD"

10% THD sounds like a lot.

Michael

you used to see this kind of spec all the time for junk-grade audio.
but jvc? sad.

 

[z]

On Apr 9, 1:16 am, mrdarr...@gmail.com wrote:

There's a cellphone ringtone that supposedly only teenagers can hear,
no one over thirty - so if they get a call, their parents/teachers are
none the wiser.

there are 6 "mosquito" ringtones from 15 khz up to 20khz. i've tested
them all (vzw tones, motorola krazr) on a 5 year old and an 11 year
old that didn't know they were being tested, and neither even looked
up.

 

[z]

On Apr 10, 12:16 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:

Bob Eld wrote:
Well, maybe I should change it to nobody in their right mind would BUY such
a lousy amplifier. You certainly can do better than 10%THD but at what
price, I don't know. This thing might fit your needs if sound quality is not
a big issue.

I think you're missing the point.

I have little doubt that this amplifier is capable of 0.1% THD at say 60W.

The 10% THD figure has simply been used in order to produce an inflated power
rating. This is considered normal practice with car audio.

Graham

exactly. this may well be a fine amp at 60 watts or 70 or whatever.
some middle management moron undoubtedly decided "this amp needs to be
100 watts! make it 100 watts or you're out!" so the engineer just
decided "OK..... have it your way" and the moron doesn't know the
difference.

 

[z]

On Apr 11, 2:44 pm, "Joel Koltner" <zapwireDASHgro...@yahoo.com>
wrote:

"Bob Masta" <NoS...@daqarta.com> wrote in message

news:47fe0425.1356369@news.sysmatrix.net...

At any rate, the manufacturer has to make a judgement call about
what power level to claim.

I've learned recently that speaker manufacturers are similar.  The good ones,
when specifiying frequency response, will tell you that it's, e.g.,
100Hz-10kHz at -1dB or -3dB... the less-reputable ones will often spec it
at -20dB !!! ...and of course usually not mention the level.

off topic: just ran into this:

"A favorite demonstration of mine was to plug the [McIntosh] ML-4
woofer section into the 120-volt wall outlet. This really captured the
attention of visitors who questioned the power handling of the system,
and it was also very loud. "
http://www.roger-russell.com/lsd1.htm

This guy's whole site captured more for an afternoon.

 

On Apr 14, 10:16 am, z <gzuck...@snail-mail.net> wrote:

On Apr 8, 11:35 pm, mrdarr...@gmail.com wrote:

Are they serious?

http://av.jvc.com/product.jsp?modelId=MODL027647&pathId=5&page=2
"100 watts per channel, 8 ohms at 1kHz, with 10% THD"

10% THD sounds like a lot.

Michael

you used to see this kind of spec all the time for junk-grade audio.
but jvc? sad.

Yep... I've noticed that lots of car audio manufacturers even refuse
to publish THD data.

Hmm...

Michael