What exactly is soft limiting?!

[Dance123]

Hi,

In the specs of the TI they say: "6 balanced outputs with +4 dB level and switchable soft limiting algorithm".

What exactly is "soft" limiting?! How is it different from other kinds of limiting?!

Thanks!

[jasedee]

I would say the "Soft" part refers to the slope or "knee" (Like Soft-Knee compression), as oppossed to a brick-wall limiter, whose function is merely to stop levels from crossing 0dBFS, for max sound

Anyone else know more?

[Drammy]

Thats exactly right Jase,

Basically the soft-limiting curve is softer or less sloped than a hard-limiting curve.

In other words when peaks pass the threshold they are reduced in volume more gently than in a brickwall limiter, for example.


Hope that makes sense.


Drammy

[grs]

I wonder if the limiting happens in the analog domain before the converter or they just do it via a digital computation. The second way would be compromising the 24bit data.

[Drammy]

I would have thought it would be pre-conversion - which would be the digital domain, not the analog. The analog signal would be the signal going out of the TI into an amp or whatever...

Why would it compromise the 24 bit data?

[JOdy]

Maybe they mean its done by a software algorythm.

[Juho L]

I'd bet my arm for digital soft knee limiter. Well, "soft limiting" is pretty intuitive term.

[grs]

Why would it compromise the 24 bit data?

well not compromise, but change the original 'sampled' audio.

Say the converter captures 24bits of sampled sound, to soft limit it would move up the loudnes information like in Waves L2, limiting/squash the peaks so they fit, but it would have to dither the data as it has changed gain in the digital domain. If that is a compromise to some producers then rightly so they are given the option to turn it off and do their own gain adjustments in their software apps.


Unless the converter can sample higher than 24bit and then give you a 'best of' from the higher bit depth and output a 24bit stream to the driver. In this hyperthetical situtation you would be getting something, not loosing something.

I gues the 'soft' part of the name implys a non analog limiting solution.

[Panopticon]

It's most definitely not going to be limiting in the analog domain...first off, there's no room for an analog limiter in the unit, and it would drive up costs ridiculously.

Also, if the signal had already clipped before D/A conversion, you'd still end up with digital distortion artifacts, so you'd just be sending shitty, distorted elements into your limiter.

[grs]

I cant quite understand the 'soft limiting' from a marketing standpoint. It kind of lulls folks into a false sense of security. You still have to avoid hitting the input to hard. They (RME, ACCESS and others) don't really explain a why person would like some pre-DAW digital limiting on their audio.
Is this something people usually do in a mixdown? ie, limit, eq, compression, pan, limit again.

[cm0s]

Maybe it's supposed to be used when playing live?

[grs]

Live? Good one. Possibly usefull. Then the marketing machine could say that.. I got the impression it was some 'anti clipping' feature.

[jasedee]

Seems like a "security Blanket" type thing...

Just for those who might not be so clued up, and drive things too hard, as a safety feature they include this option???

I dont know......

[Panopticon]

Well, it's pretty easy to get the Virus to clip internally at times with patch volume turned to 127, and I doubt everyone knows about the LED mode where it tells you if it's clipping. Seems like a useful enough feature to me...

[grs]

just read this on the RME site...
"A soft-limiter, which has been tuned especially for musical instruments, efficiently prevents overloads of the A/D-converter."

At least their version is suggesting an analog stage before the converter!

[Gopal]

How do you figure that grs?

You can have digital clipping too