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Console Channel levels vs stereo bus levels?
Hi All,
I was wondering on your approaches on stereo bus output levels (while mixing) in order to keep those levels under control: here's the situation: we send all tracks (separately) from PT HD to an SSL console. The stereo mix is converted to digital with a HEDD192 and recorded in Sadie. PT is referenced to 0VU = -18dB(FS). Most of the time, the tracks we get (to mix) arrive at fairly hot levels (distortion guitarsliving in the -2 to -4 dB range). So, already by sending out everything at 0 out to the SSL, the console's meters tend to be pegged from the start. Throw in a few dB's of compression where needed and we'll end up with a mix that is WAY too hot (By the way, on the SSL's output 0 VU = -14dB). Not to mention that it is also too hot for the HEDD (also calibrated for 0VU = -14dB). So what's to do? 1/ Lower the master fader on the console? possibly yes, but if the levels are that hot, will the tracks not already be distorted prior to their arrival at the quad bus? or at the quad bus input? 2/ Lower the output levels in PT so that the tracks hit the console at a lower starting level? Is that a good way to start or would you rather recalibrate PT so that for instance 0VU=-14dB (and thus reducing the headroom by 4 dB??) 3/ Bring down the individual faders by x dB? Yes but this is not an option when you're halfway a mix as it changes levels to sends, submaster inserts etc... 4/ Recalibrate the HEDD? 0VU=-16dB is the most you can get (I believe) but then that would still not solve the problem if the quad bus is overloading?? How do you folks deal with this? How's the headroom and calibration thing affecting you? Thanks & All The Best, R. |
#2
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hey there--
I've spent a fair amount of time doing exactly the same thing you are. In my experience, setting the PT outputs to -18 nearly always results in console overload at the input. -15 makes a bit more sense in general; with older SSL's I've sometimes had to go all the way to 0VU= -12dBFS to avoid having channels break up on me before I've even done anything. This will also enable you to run more faders closer to unity, where their resolution is greatest. By the way, lowering those outputs doesn't reduce your headroom at the console--at mix, it just avoids overload at the input. At the same time, in my experience it's hard to get enough output from most analog consoles to drive digital systems to 0dBFS without distortion when 0VU is set to -18dBFS. Hope this helps, Gordon Rice |
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In article ,
The Alamo wrote: Hi All, I was wondering on your approaches on stereo bus output levels (while mixing) in order to keep those levels under control: here's the situation: we send all tracks (separately) from PT HD to an SSL console. The stereo mix is converted to digital with a HEDD192 and recorded in Sadie. PT is referenced to 0VU = -18dB(FS). Most of the time, the tracks we get (to mix) arrive at fairly hot levels (distortion guitarsliving in the -2 to -4 dB range). So, already by sending out everything at 0 out to the SSL, the console's meters tend to be pegged from the start. The first thing you might want to do is re-calibrate the Protools output so that -14 dBfs = 0 VU on the SSL. (BTW, also re-calibrate the inputs to Protools to the same standard, so that the Protools system is unity gain input to output!) Throw in a few dB's of compression where needed and we'll end up with a mix that is WAY too hot (By the way, on the SSL's output 0 VU = -14dB). Not to mention that it is also too hot for the HEDD (also calibrated for 0VU = -14dB). So what's to do? 1/ Lower the master fader on the console? possibly yes, but if the levels are that hot, will the tracks not already be distorted prior to their arrival at the quad bus? or at the quad bus input? You need to address your gain structure when mixing....If the input channels aren't distorting (see below) then the quad bus needn't be distorting in front of the quad fader. It sounds as if your setting up your levels too hot at the early stages of the mix, and "painting yourself into a corner" with the levels. Begin the mix with the levels lower! Then when you start adding stuff, you've got some headroom to work with. But if you still find the quad bus too hot, use the VCA grouping to set up group masters, and pull the overall level feeding the quad bus down until it's comfortable, or use the "VCA trim" control to do the same. Be aware that when you use the "VCA trim", any effects sends returning to large faders need to be set to "I" (independent) to make sure that the returns levels aren't being reduced at the same time the send levels (from the post-fader sends) are also being reduced! 2/ Lower the output levels in PT so that the tracks hit the console at a lower starting level? Is that a good way to start or would you rather recalibrate PT so that for instance 0VU=-14dB (and thus reducing the headroom by 4 dB??) It's possible that you can overload the input channels on the SSL with your current gain structure, but the SSL input stage should be good for at least +24 dBu, several dB hotter than the Protools rig can deliver with your current calibration. Of course adding compression, or boost EQ will push you into clipping, so you should reduce the levels feeding the channel, either by recalibrating Protools as above, or by trimming the line inputs down (makes total recall a little more time-consuming), or by lowering the faders in Protools (probably the easiest and most expedient method, but some claim that Protools sounds worse when the "faders" are not at unity gain...make your own tests and choose your poison). 3/ Bring down the individual faders by x dB? Yes but this is not an option when you're halfway a mix as it changes levels to sends, submaster inserts etc... Setting up and using VCA subgroups makes changing the individual faders unnecesary, but you would need to adjust threshold levels on any dynamics processors that are post-fader (quad bus compression, channels "float"ed out to groups and compressed, etc...) And, since sends are ALMOST always post-fader, they're not a problem (unless you're doing dynamics from an effects send)....you WANT the send levels to drop when you drop the level of the track. Keep in mind that a mix is a changeable thing...there's nothing wrong with just pulling all the faders down and re-building the mix again if it's out of control....you've already set up the EQ and effects for each track, so it shouldn't take more than a couple of minutes to just pull up the faders again and establish a balance of the sounds you already got! It's a VERY useful technique sometimes....it'll help you re-focus the mix on what's important. (sorry if I've gone off on a little tangent here!) The point is, if the individual channels aren't clipping, than there are several ways to keep from clipping the mix bus. 4/ Recalibrate the HEDD? 0VU=-16dB is the most you can get (I believe) but then that would still not solve the problem if the quad bus is overloading?? You might want to do that too. Remember that the quad bus output is capable of delivering more level without clipping than the HEDD is likely to be able to accept. If you've got good levels at the HEDD when the master fader is all the way up at unity, then it's very unlikely you're distorting pre-fader (unless you've got some wacky stuff going on in the quad insert). Mix to the level you need to see at the HEDD and ignore (to a point) the meters on the console. At 0 VU = -16dBfs, you will probably end up with the console meters pretty hot! How do you folks deal with this? How's the headroom and calibration thing affecting you? The SSL rooms I work are calibrated to 0 VU = -16 dBfs (I'm considering re-calibrating to -14), so quite often with tracks that are recorded in all-digital rooms with levels approaching (and often crashing into!) 0dBfs, I usually end up pulling some of the "faders" in Protools down 5-8 dB if for no other reason than to keep the meters in the console from banging all day long and annoying me! (I mix pretty quietly) And I use subgroups and the VCA trim to get the final bus level where I want it once I've got the mix together....experience helps me get close to the ballpark but you always need to tweak up or down a little just before printing the mix. Jeff C. -- Anti-Spam email address in effect. My real email should be pretty obvious to an actual human being. |
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