Question for you Mastering Folks

When you use a High Pass filter, what kind of slope do you like?  6dB/octave? 12,  24?  Something else?
How about HPF on the sides channel using M/S?  Same question about slopes......
Thanks!
Best,
Bruno2000

Isn't mastering a bit late in the day to be applying an HPF?

Cheers

ian

ruffrecords said:

Isn't mastering a bit late in the day to be applying an HPF?

Cheers

ian

Click to expand...

It's always late somewhere........
Best,
Bruno2000

bruno2000 said:

When you use a High Pass filter, what kind of slope do you like?  6dB/octave? 12,  24?  Something else?
How about HPF on the sides channel using M/S?  Same question about slopes......
Thanks!
Best,
Bruno2000

Click to expand...

It really depends on what you're trying to fix/create. If it's a cure for overall boominess, a gentle slope is what you want; in fact, in that case, I would rather use a parametric EQ with a large BW (small "Q") set at 20 Hz, and just a few dB cut. But if you want to get rid of mechanical noises, you want a higher-order filter. I often use a 4th-order HPF (24dB/oct). Having to use it at mastering time should be rare, but it is more and more often that I receive mixes that are deliberately not cleaned up; for some reason, the new generation of SE want to deliver the rawest performance and rely on the ME to deliver what will please the producer.

The Neumann HT75 which was in their later vinyl mastering consoles were Sallen-Key 18dB/oct.  A 16K 18dB/oct lpf is probably on most records you hear. The earlier HT66 were passive and 12dB/oct but they were replaced by the HT75 in 1975.

I use HPF and LPF all the time. To decide on the frequency and slope, I use my ears and keep my eye on the meters if the reason is more technical than aesthetic.

Before plug ins the reason you used a certain frequency and slope had more to do with what you had than what you wanted.

Gold said:

A 16K 18dB/oct lpf is probably on most records you hear.

Click to expand...

Yep and I had to learn that lesson the hard way when trying to cut Van Gelder Blue Note records at almost full frequency...Those recordings are a lot brighter off the tape.

***for those who are interested, a cutting lathe has a harder time cutting high frequencies than low frequencies. The coil in the cutting mechanism will heat up with a lot of high frequency content. Filters and de-essers are used heavily in cutting. A sustained 10K tone even at 0dBu would burn out the coil.

Regarding filters in digital mastering, if using them creatively, the steeper slope will have more of a resonant peak at the filter frequency and have more of a "sound". So there's really no definite answer to that. Just start at 6db/oct and start getting steeper until you get to where you want it to be.
But if your fixing something, its always going to be a compromise between taking the "broken" sound out and keeping the original sound as close to what its supposed to sound like. Again no definite answer, just start at 6db/oct and go up.

Regarding mid/side I have always found peaking eq (cutting) to work better than filters. Like crashing cymbals, I will sweep around in the sides with a medium Q dip until I find the loudest part of the offending frequency and cut there.
There are also some powerful mid/side multi-band compressors out there that allow you essentially do the same thing as with the eq but dynamically.

Just use the force Luke