10% THD?

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:

"100 Watts per Channel x 2 in Stereo Mode with less than 0.9% THD,

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

Pretty standard figure for quoting watts for in car entertainment equipment.

Never previously seen it used for any home audio though. It's probably ~

Graham

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?

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.

That would be normal.

Graham

Yes you can.

Graham

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

"BobG"

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

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.

At least not more than once ;)

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...

Support info:

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...

Thanks,

Michael

THD...

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

=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

"BobG"

take a breath - you are not talking about the same topic as others here !!

Peak clipping ( = hard clipping ) of a CONTINUOUS sine wave is VERY audible, even at low percentages. The harmonics generated go up to 5, 7, 9 and 11 times the fundamental - if they fall in the range of 1 to 5 kHz their presence is obvious us to anyone who is not deaf.

OTOH - occasional transient clipping of a music or speech signals is virtually inaudible, specially if each clipping event is under 2mS duration. Such occasional transients may be clipped at high percentages of their unclipped amplitude and still remain hidden to listeners.

Some power amplifiers have fast acting signal clipping indicators ( ie the Crown IOC system) and it is easily demonstrated that the LED clipping light will flicker regularly on normal music program WELL before any listener can hear a problem.

..... Phil

s here !! =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 I claimed that one cannot see 3% distortion in a sine wave on a scope. I got a response that this is utter nonsense, and its easy to see 1% THD on a scope. So I want to synthesize a waveform with fundamental of amplitude X and 3rd harmonic down at 0.03X. Then I will plot it and see for myself if in fact 3% is easily visible and my claim was utter nonsense. Of course, I'll be using a computer monitor with about 3 times the vertical resolution of most scopes, but that should just make the distorion easier to see.... I'm making the test harder for myself. I wouldnt want anyone to say my experiment was biased in favor of my claim. Just trying to defend myself against the assertion that I have spoken utter nonsense.