Ethan Winer
Acoustics Expert
Well, analog is usually also very clean right up to the point of hard clipping. And I did address that above:
Setting levels to avoid clipping below digital zero is not that difficult.
--Ethan
Volume level at recording
- Thread starter ManInMotion711
- Start date
Well, analog is usually also very clean right up to the point of hard clipping. And I did address that above:
Setting levels to avoid clipping below digital zero is not that difficult.
--Ethan
DM60
Well-known member
My understanding is analog does distort above 0 dB, but it can be considered a desired result, verses digital sound is just bad sounding.
Farview
Well-known member
Usually, being the operative word. Analog usually has a soft knee sort of thing as you approach clipping, where as digital is completely linear until zero where it flat-lines.
Popular misconception, brought about by the "warmf" fraternity no doubt.
Most analogue systems employ amplifiers with a large degree of negative feedback. Such amplifiers deliver very low distortion up to nearly clipping then whammo!
But triode valves for instance deliver low distortion at low levels* (but still tons more than an NE5532!) because even at say +22dBu they have tens of volts of headroom due to the high supply HT. However, hi-fi valve power amps with high feedback also have a very fast overload curve.
Tape too has progressive distortion but even this can "whammo!" Older systems used something called "pre-distortion" and this gives very clean results at higher than normal levels but then sudden onset ***t!
*Actually triodes have a sort of built in negative feedback but lets us all K.I.S.S. Eh'?
Dave.
snow lizard
Dedicated Slacker
Ethan said:
Accuracy is relative. VU meters were designed with intentionaly slow ballistics to provide a more accurate representation of RMS levels. They don't indicate peaks very well but that's not what they're for. Peak information is going to change depending on the transient content of the source. A snare hit that peaks at +0.1 dBFS probably won't sound obviously distorted even though it will ignite the overload indicator. A synthesizer set to a sine wave recorded at -6 dBFS might be a different story. The RMS value of the snare might still be within reasonable limits even though the peaks are loud. Go to a source with no transients and you could be trying to print a signal at 3 or 4 volts from your Chinese preamp. Different results.
In that sense, peak information is a little bit useless.
I do agree that it's more accurate though.
Bobbsy
Boring Old Git
Wot ecc83 says.
Within the analogue domain, 0dBu is an arbitrary measure (around .7746 Volts) and has no particular significance to the onset of clipping distortion. Generally, analogue gear is designed to have plenty of headroom above that figure--18dB of headroom is fairly typical, hence the frequent statement that 0dB(FS) is equal to +18dBu. However, this varies from one piece of gear to another--a lot of Sony professional VTRs are set so +21dBu is 0dB(FS) but I've seen other bits of gear with only 12 or 14 dB of headroom.
For Ethan--I agree that a little bit of digital clipping on a recording with a normal "real world" dynamic range isn't a problem. However, push it harder than the 2dB you mention and the effect on the perceived sound deteriorates into an unpleasant mess fairly quickly. However, I think what most people are trying to get across is that going above 0dB(FS) in a digital world is a very different thing to going above 0dBu in an analogue world with lots of headroom.
Ethan Winer
Acoustics Expert
Exactly. I wish more people would actually test this stuff, because it's not that difficult to do!
As for the notion that digital clipping is worse than analog clipping, it really isn't because it's exactly the same thing. At least when clipping a normal preamp type circuit. I just did that test again using a chunky rhythm guitar part that peaks at around -3.5 dBFS. Then I raised the gain by 10 dB to push it 6.5 dB over clipping, then I lowered the gain by 4 dB to more closely match the original volume. (It still sounds louder but who cares.) As you can hear, the over-driven sound is not terrible, just a little more grungy than before, as if the guitar amp was pushed a bit harder. MP3 clips are attached.
--Ethan
View attachment Chords.mp3
View attachment Chords+10.mp3
Ethan Winer
Acoustics Expert
It all depends on what you need! If you need an indication of how loud something sounds, then average levels are appropriate. But if you need to know whether your record levels are acceptable, which is what most recordists care about most of the time, then a peak meter is clearly the better choice.
--Ethan
Not Shure what you're doing here.Exactly. I wish more people would actually test this stuff, because it's not that difficult to do!
As for the notion that digital clipping is worse than analog clipping, it really isn't because it's exactly the same thing. At least when clipping a normal preamp type circuit. I just did that test again using a chunky rhythm guitar part that peaks at around -3.5 dBFS. Then I raised the gain by 10 dB to push it 6.5 dB over clipping, then I lowered the gain by 4 dB to more closely match the original volume. ...[/]
Is this test driving +6 over full scale into an A/D converter?
Thanks
Wayne
Mo Facta
Farts of Nature
That is essentially what I was trying to get across. It just irks me a little when people talk about "digital clipping". It's just not as big a deal to me as distorting an ugly sounding analogue end due to clipping.
Mastering engineers have been intentionally clipping their masters for extra loudness for years. Go take a look at any uber-loud album from the mid 2000's and see it for yourself.
Cheers
Ethan Winer
Acoustics Expert
No, I simply raised the volume of the Wave file so it became clipped. That's the same as overdriving an A/D input. Either way you get hard flat-topping, similar to overdriving a typical solid state analog circuit.
I can't imagine that overdriving an A/D input is any different, but I'll be glad to see/hear such an experiment if anyone else here cares to try it.
--Ethan