Just out of curiosity and mainly directed to those who have used real mixing consoles such as SSL and the like, what are the slopes for hi/low cuts on such boards and are they fixed slopes?

This is a hard question to answer because here are a few variables. One variable are the type of HPF you may have access to and the other variable is the material you are applying the HPF effect to.

With HPF's there are two main things to consider. One is the cut off frequency and the second is the slope of the filter. There is no right or wrong freq or slope settings. 

It really does depend on how the material sounds and then you can make a informed choice as to where the cut off freq should be and the most effective slope required.

To answer Rasure's question about filters on analog mixers. The SSL AWS 948 for example uses an 18 dB/Oct slope on its filters. But analog mixer slopes are only a guide. The problem with analog circuitry is that it cannot easily create the very steep slopes (eg 48 dB/Oct) that digital plugins can.

Sometimes 6 db/Oct with a much higher cut off freq is perfect and other times 48 dB /Oct slope is perfect with quite a low cut off freq. Just depends on what you are trying to do. The former case will just ease the low end off an otherwise slightly boomy track but the latter will kill any subsonic rumble present but not touch the bottom end at all. 

elsongs

Been doing it since the old Sonar EQ. Depends on the application and other tracks. I use low-end rolloff to make room for certain instruments (kick drum, bass guitar/bass synth) to not compete for the low-end with other instruments. I also use it for cymbals/high-frequency percussion to make them more transparent sounding and less heavier. 

Absolutely agree.  If I am recording solo guitar, I am going to EQ the bottom end of the guitar completely differently than if I was mixing the guitar with a full band and need to make room for the bass guitar, etc.


Asking "what setting works" means nothing really, as every case if different.  That's why these FX have sliders and knobs and not just an on/off switch, right?


You absolutely have to use your ears for each and every song.  An arbitrary setting just isn't applicable.  For instance, going back to the guitar example - where was it mic'd?  At the sound-hole? At the 12th fret?  You are going to EQ very differently for each position.  What mic was used - omni or cardioid?  Again you will probably be EQing differently depending on the mic you used due to proximity effect, or lack thereof.


I always smack my forehead when this type of question is asked.

Voxengo span and a pair of ears works best for me =)

Shambler


Voxengo Span and a pair of ears works best for me =)

Fixed

I think lance and john summed it up. Depends on what you are working on and using your ears is usually what it will come down to. For me, most of my work involves voice overs so i tend to go with the gentler slope because most of the frequencies are not even close to low end. if i were working with getting a bass guitar, two separate kicks drums and a sub bass synth sound to sit in a mix, I would be more apt to go sharper. As also pointed out, SPAN (or equivalent analyzer) is your friend.

John mentions cleaning up mud and there is another situation which can result in low end being muddy and that is when you get a build up around 200 to 300 Hz or so. When this occurs you need to create a EQ with a suitable dip around these frequencies but the low end needs to come back up to normal though.

This is NOT the same as using a HPF to remove unwanted bass in a track or buss. It is quite a different thing and you may be using a HPF incorrectly when actually it is this 200 to 300 Hz mud that you should be cleaning up instead using a dip EQ.

If you are not sure which one to try, if you feel you are not getting what you want from the HPF then try the dip around 250 Hz instead and see how you like it. Often it sounds amazing and totally cleans up a track or buss big time. Sometimes a little HPF in conjunction with the 250 Hz freq dip works great too.

Using spectrum analysers are not that great either in this area. They tend to work better when there is a lot of excess in a certain area and easy to pinpoint. I have often found they can still look OK down low but the bottom end is still not sounding right. Use your ears first. I find that spectrum analysers work best after 8 hours of mixing and you cannot tell what is what any more and the problem frequencies are higher up in the spectrum as well.

I don't get it Jeff. You don't trust an analyser when your ears are fresh but when you are feeling a bit jaded they work ok? 

I have Izotope Insight and it works all the time.

  Hey, sharke, have You learned something new about that activity in the low frequencies? In my case, I have to go very high with the cut to see the results in Voxengo... [pics showing 30db steep cut. #1: 20Hz; #2: 70Hz] http://pokazywarka.pl/r0j7hm/

backwoods


I don't get it Jeff. You don't trust an analyser when your ears are fresh but when you are feeling a bit jaded they work ok? 

I take that to mean fresh ears are always better than an analyser. If you're tired, your listening ability goes down below the level of the analyser usefulness (or at least increases uncertainty of your decisions you make by ear), hence the analyser is now the best or most reliable/consistent option.


But the better option still would be to rest when the ears are tired and never need to resort to the analyser. This is not always possible, however, under a deadline.




I personally don't tend to find analysers really do much for me when I'm mixing. I might use them for a quick check of something, but I'll always prefer to trust my ears first. An analyser might trick you into thinking you're hearing something which you're not. Hence I'll only bring it up if I feel I really need to.