To Soft-Limit or Not to Soft-Limit?

[Bambison]

Just curious as to the pros & cons of using soft-limiting on the 192 (or Apogee or ?).

[thin ice]

The pros are getting a higher level into pro tools. Not sure how much this matters with 24bit and a full band, but could be more important on sparse acoustic music. I have not noticed any downside. I just have not got any peaks or digital distortion since using the Apogee and leave it on always.

[PTUser NYC]

Getting a full scale level won't increase the resolution any unless your microphone, preamplifier and room have a dynamic range over 132db. Since they don't, you can track with peaks at -18dbFS, and still get full resolution.

Soft limit is a neat idea, and sometimes sounds good, but you have to provide such tremendously hot levels from your preamp in order to bring it into play. If your converter is set up so that OdbVU (on or near the sweet spot of most preamps) = -14dbFS (14 db below full scale on the meter), then you need to be operating the mic preamp at +11db in order to even be affected by the soft limit feature. That is a lot of potential distortion, and certainly a huge loss of headroom that you spend just to get the soft limit feature in.

People don't understand that converters were designed to see levels way below full scale. Plug Ins love the headroom. The sound is SO much better.

If you need a full scale mix for 16 bit files (such as a CD) then simply make up the gain in the mix bus compressor or something. Try working with correct levels, you'll be amazed at how much pro tools opens up. (Which is to say, how much distortion your mic pres were adding, and you missed individually, but when added up made you question the pro tools mix bus.)

So, soft limit - OK, but why can't I set the threshold MUCH lower?

[brian jacoby]

Both the Soft-Limit feature of the Apogee converters, and the Soft-Clip on the 192s serve well for very transient sounds. Remember when you are refering to a "0 VU" signal we're talking about an average (RMS) level. This doesn't account for sudden peaks and transients, which can sometimes be 20-30dB HIGHER than 0 VU (especially if we're talking about drums, picked strings,etc.) The intention of these Soft Limit features are really protection from overs on these brief, sudden transient sounds. I find the Apogee to be a little more transparent in how it handles this (though the converter itself is a bit more colored) than the 192. I would compare the 192's Soft Clip more to the sound of the "Overkiller" feature in the Prizm converters, sounds a bit more like straight limiting to me.

[frenchman]

I love the AD8000, but I never use soft limit as is does not come near plugins designed to take care of transients like Mcdsp AC or DUY Tape & Valve, L1, etc.
I feel like someone is puttings the brakes on the sound, because in actual fact it is a limiter and I can hear this effect already a few dbs as the signal approaches peak level.
Anyway this feature is near obsolete now when working in 24 bits sessions, as you can transcribe the full headroom of the AD converters.

[Mt.Everest]

I wish everyone who used Protools understood the basics points that PTUserNYC makes. Then sessions I'd get from other engineers (mostly ppl with their own setups thesedays) would be so much more a pleasure to work in.

Everyone should carefully read this over and over to make sure its clear, because it is right:

Getting a full scale level won't increase the resolution any unless your microphone, preamplifier and room have a dynamic range over 132db. Since they don't, you can track with peaks at -18dbFS, and still get full resolution.

Soft limit is a neat idea, and sometimes sounds good, but you have to provide such tremendously hot levels from your preamp in order to bring it into play. If your converter is set up so that OdbVU (on or near the sweet spot of most preamps) = -14dbFS (14 db below full scale on the meter), then you need to be operating the mic preamp at +11db in order to even be affected by the soft limit feature. That is a lot of potential distortion, and certainly a huge loss of headroom that you spend just to get the soft limit feature in.

Everyone needs to forget about level in protools when recording.. Setup your levels so your analog stuff is operating in its optimun space, usually averaging around 0VU. THIS IS ALL YOU NEED TO KNOW when getting levels when recording. Dont even look at the meters in Protools for Gods sake!. You will be sooo much happier with your sound if your front-end is operating where it is designed to be.
In case unclear, please refer to above.

Sorry for the rant, but I get excited when i see statements like PTUserNYC's that I wish all would follow like gospel.
MT

[steins]

What they said! In the world of 24 bit recordings, the "make your levels as near to 0dBfs as possible"-gospel is in my opinion [bleep] when talking multitrack recordings. If you calibrate your A/D to -18dBfs and let your analog equipment work where they sound their best (which could be way beyond 0VU...but that´s OK when you got the headroom for it)...no need to use soft-limit.

Stein Tore

[Felix]

i checked this thread out to see if someone would set things straight. you summed things up very well. i should just print it out to show to people. then i can save myself the irritation.
it is very true that many people (mainly starting out) don't understand this at all. maybe never really will. maybe due to misleading gear propaganda and eager sales people.
whatever the case, it only makes us in the know look better in the end.

[thin ice]

If you look at it this way I guess Apogee just wasted their time even bothering with this feature. I am not recording levels that hot like we used to for tape, but still used to get the odd over with transients. I still find it a useful feature. I cannot hear it in operation, but just avoid the occasional red light.

[Felix]

i wouldn't say it was a waste of time. there are some scenarios in which Soft Limit could be useful. also, in terms of making sales for Apogee, there are many who might appreciate the feature as a selling point regardless of whether they know what they're doing.