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Author: BobGDate: 23:44 08-04-08
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But the waveform that gets clipped and produces the 10% distortion
probably occurs less than 1% of the time... when the car crashes or
the tank cannon fires, etc, so you probably cant tell if the KaBoom!
is distorted or not... 99.9% of people have never heard a live tank
cannon at a range of less than several miles anyway.
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On Apr 8, 8:44 pm, BobG <bobgard...@aol.com> wrote:
> But the waveform that gets clipped and produces the 10% distortion
> probably occurs less than 1% of the time... when the car crashes or
> the tank cannon fires, etc, so you probably cant tell if the KaBoom!
> is distorted or not... 99.9% of people have never heard a live tank
> cannon at a range of less than several miles anyway.
Well, for nearly the same price ($130 at Wal-Mart), you can get this
instead:
http://www.sherwoodusa.com/prod_rd6500.html
"100 Watts per Channel x 2 in Stereo Mode with less than 0.9% THD,
40 Hz-20 kHz, 6 Ohms"
The THD for a range 40Hz-20kHz should be greater (summed) than the THD
for a single frequency (1 kHz in the JVC above), right?
Michael
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Author: EeyoreDate: 23:57 08-04-08
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Author: EeyoreDate: 23:58 08-04-08
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mrdarrett@gmail.com wrote:
> On Apr 8, 8:44 pm, BobG <bobgard...@aol.com> wrote:
> > But the waveform that gets clipped and produces the 10% distortion
> > probably occurs less than 1% of the time... when the car crashes or
> > the tank cannon fires, etc, so you probably cant tell if the KaBoom!
> > is distorted or not... 99.9% of people have never heard a live tank
> > cannon at a range of less than several miles anyway.
>
> Well, for nearly the same price ($130 at Wal-Mart), you can get this
> instead:
>
> http://www.sherwoodusa.com/prod_rd6500.html
>
> "100 Watts per Channel x 2 in Stereo Mode with less than 0.9% THD,
> 40 Hz-20 kHz, 6 Ohms"
>
> The THD for a range 40Hz-20kHz should be greater (summed) than the THD
> for a single frequency (1 kHz in the JVC above), right?
THD typically increases with frequency (due to falling open-loop gain) so
a 20kHz figure will be more than a 1 kHz figure.
Graham
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On Apr 8, 8:58 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:
> mrdarr...@gmail.com wrote:
> > On Apr 8, 8:44 pm, BobG <bobgard...@aol.com> wrote:
> > > But the waveform that gets clipped and produces the 10% distortion
> > > probably occurs less than 1% of the time... when the car crashes or
> > > the tank cannon fires, etc, so you probably cant tell if the KaBoom!
> > > is distorted or not... 99.9% of people have never heard a live tank
> > > cannon at a range of less than several miles anyway.
>
> > Well, for nearly the same price ($130 at Wal-Mart), you can get this
> > instead:
>
> >http://www.sherwoodusa.com/prod_rd6500.html
>
> > "100 Watts per Channel x 2 in Stereo Mode with less than 0.9% THD,
> > 40 Hz-20 kHz, 6 Ohms"
>
> > The THD for a range 40Hz-20kHz should be greater (summed) than the THD
> > for a single frequency (1 kHz in the JVC above), right?
>
> THD typically increases with frequency (due to falling open-loop gain) so
> a 20kHz figure will be more than a 1 kHz figure.
>
> Graham
And the THD should be higher at 4 or 6 ohms than at 8, right?
M
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Author: BobGDate: 00:48 09-04-08
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I dont think you can see the difference between 0.1% and 3% distortion
in a sine wave. Scope aint good enough. But 'visible clipping' is
about 10%, and is surprisingly inaudible. Try it yourself. Get a scope
and a cd player and a smallish amp and a speaker. View amp output on
scope. Turn up till you see visible clipping. Compare sound with
clipping to sound without clipping.
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Author: Michael A. TerrellDate: 00:55 09-04-08
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Author: EeyoreDate: 00:56 09-04-08
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mrdarrett@gmail.com wrote:
> Eeyore wrote:
> > mrdarr...@gmail.com wrote:
> > > BobG <bobgard...@aol.com> wrote:
>
> > > > But the waveform that gets clipped and produces the 10% distortion
> > > > probably occurs less than 1% of the time... when the car crashes or
> > > > the tank cannon fires, etc, so you probably cant tell if the KaBoom!
> > > > is distorted or not... 99.9% of people have never heard a live tank
> > > > cannon at a range of less than several miles anyway.
> >
> > > Well, for nearly the same price ($130 at Wal-Mart), you can get this
> > > instead:
> >
> > >http://www.sherwoodusa.com/prod_rd6500.html
> >
> > > "100 Watts per Channel x 2 in Stereo Mode with less than 0.9% THD,
> > > 40 Hz-20 kHz, 6 Ohms"
> >
> > > The THD for a range 40Hz-20kHz should be greater (summed) than the THD
> > > for a single frequency (1 kHz in the JVC above), right?
> >
> > THD typically increases with frequency (due to falling open-loop gain) so
> > a 20kHz figure will be more than a 1 kHz figure.
>
>
> And the THD should be higher at 4 or 6 ohms than at 8, right?
That would be normal.
Graham
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Author: EeyoreDate: 00:56 09-04-08
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BobG wrote:
> I dont think you can see the difference between 0.1% and 3% distortion
> in a sine wave.
Yes you can.
Graham
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Author: EeyoreDate: 00:58 09-04-08
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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
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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
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Author: Phil AllisonDate: 01:31 09-04-08
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"BobG"
>
>I dont think you can see the difference between 0.1% and 3% distortion
> in a sine wave. Scope aint good enough. But 'visible clipping' is
> about 10%, and is surprisingly inaudible. Try it yourself. Get a scope
> and a cd player and a smallish amp and a speaker. View amp output on
> scope. Turn up till you see visible clipping. Compare sound with
> clipping to sound without clipping.
** Might be almost true for small, SE tube amplifiers with zero negative
feedback.
Their very soft rounding to the wave crests is not easy so easy to notice
compared to typical hard peak clipping seen with all high feedback
amplifiers - particularly with 100 / 120 Hz modulation added from an
unregulated supply.
I can hear that when the THD meter says it is only 0.5 %.
.... Phil
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Author: Stephen J. RushDate: 02:49 09-04-08
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On Tue, 08 Apr 2008 20:44:11 -0700, BobG wrote:
> But the waveform that gets clipped and produces the 10% distortion
> probably occurs less than 1% of the time... when the car crashes or the
> tank cannon fires, etc, so you probably cant tell if the KaBoom! is
> distorted or not... 99.9% of people have never heard a live tank cannon
> at a range of less than several miles anyway.
I've heard 3-inch naval rifles from aboard the firing ship, and tank main
guns from about 200 yards. It's nothing like the prolonged, all-bass
boom you hear in most movies; the real thing is as flat and abrupt as a
slammed door. I suspect that the Hollywood sound-effects community spent
a lot of time developing something that would sound plausible without
driving their recording systems nuts.
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Author: Jon SlaughterDate: 03:40 09-04-08
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"BobG" <bobgardner@aol.com> wrote in message
news:8dc15a1c-3336-40ee-88c9-2483115bd0cc@8g2000hsu.googlegroups.com...
> But the waveform that gets clipped and produces the 10% distortion
> probably occurs less than 1% of the time... when the car crashes or
> the tank cannon fires, etc, so you probably cant tell if the KaBoom!
> is distorted or not... 99.9% of people have never heard a live tank
> cannon at a range of less than several miles anyway.
At least not more than once ;)
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Author: BobGDate: 08:34 09-04-08
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On Apr 9, 12:55=EF=BF=BDam, "Michael A. Terrell" <mike.terr...@earthlink.net=
>
wrote:
> =EF=BF=BD =EF=BF=BDI have seen 2% THD described as sounding like a barrel =
of nails in a
> cement mixer.
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D
But in court, this would be objected to as hearsay. We have all heard
horrible distorted clipped hash coming from and amp, but was that .5%,
5%, or 50% THD we were hearing at the time? Anyone can hear a diff in
an AB comparison with a graphic EQ in and out, but few can characteris
it quantatatively and within about an octave. Unless they have a
couple decades experience in live sound reinforcement like me and a
couple of buddies. They could win a bet in a bar if you took in a
signal generator and a spectrum analyzer. Perfect pitch.
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Author: Bob EldDate: 14:20 09-04-08
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<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.
>
> Michael
It is a lot. Most likely a misprint. Nobody in their right mind would spec.
an amplifier with that distortion nor would they rate an amplifier at its
clipping level as has been suggested.
Since getting less than one percent even less than 0.1% THD is trivial these
days with modern semiconductor circuitry it would seem that this spec sheet
is probably in error.
Most likely the printer or web master left out a decimal point and nobody
caught it. Call JVC and ask.
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On Apr 9, 11:57 am, mrdarr...@gmail.com wrote:
> On Apr 9, 11:20 am, "Bob Eld" <nsmontas...@yahoo.com> wrote:
>
>
>
> > <mrdarr...@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.
>
> > > Michael
>
> > It is a lot. Most likely a misprint. Nobody in their right mind would spec.
> > an amplifier with that distortion nor would they rate an amplifier at its
> > clipping level as has been suggested.
>
> > Since getting less than one percent even less than 0.1% THD is trivial these
> > days with modern semiconductor circuitry it would seem that this spec sheet
> > is probably in error.
>
> > Most likely the printer or web master left out a decimal point and nobody
> > caught it. Call JVC and ask.
>
> I downloaded the manual, and it also has 10%
THD...http://resources.jvc.com/Resources/00/00/90/LVT1507-001A.pdf
>
> Support info:http://support.jvc.com/consumer/support/index.jsp
>
> I called their 800 number, and heard an amazingly distorted
> recording. Maybe distortion is company policy? ;-)
>
> I'll try e-mailing them (but won't hold my breath).
>
> Well, if it does end up a mistake, this would be a pretty good
> product...http://www.walmart.com/catalog/product.do?product_id=5301826
>
> Thanks,
>
> Michael
I called them again (the phone lines were clear this time).
Confirmed that, yes, it is 10%. (Tech guy asked his supervisor).
okay then...
Either way, the manual said 8 ohm to 16 ohm impedance only... I was
thinking of using the 4-ohm subwoofer speakers I got (great deal on
car audio) that I currently use on my Onkyo.
Oh well..
"Nobody in their right mind..." ha ha ha.
Thanks guys
M
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Author: BobGDate: 20:33 09-04-08
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On Apr 9, 12:58=EF=BF=BDam, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:
> BobG wrote:
> > =EF=BF=BDBut '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
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Lets generate a test waveform with 1khz fundamental and 3% of 3khz...
formula is something like wave[n]=3D350.0*sin(twopi*n/1024.0) + (350.0
* 0.03)*sin(twopi*3.0*n/1024.0); I'm using ampl of 350 because I'm
plotting 1024*768. You agree this amplitude of 3rd harmonic will give
3% THD?
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