Hi-Pass Filters

Discussion in 'Mastering' started by bassmac, Jan 8, 2002.

  1. bassmac

    bassmac Guest

    Are hi-pass filters commonly used in mastering?

    I ask this because when I put a freq analyzer on many a commercial CD, it sure *looks* like there is.
  2. brad

    brad Guest

  3. MikeG

    MikeG Guest

    I broadcast a regular live 2 hour jazz broadcast on FM each week and I've noticed that occasional records drive the pre-transmission compressor much harder than the apparent levels justify. This happens on recordings mainly from a certain audiophile record company (no names) There is a LF content present affecting the compressor, too low to serve any purpose (on FM radio anyway) but it sure upsets the levels by applying far too much compression.
    What do you think should be the realistic filter out point for LF without upsetting the audiophiles?
  4. brad

    brad Guest

  5. joe lambert

    joe lambert Active Member

    Oct 17, 2001
    321 West 44th Street Suite 1001
    Home Page:

    Yes. Hi pass filters are sometimes used with mastering. Before the CD Vinyl's limitations made it nessassary to roll off excessive bass to be able to cut a record. If you have "too much" low end it will make it physicaly impossible to cut the record. Also the more bass the less overall level. So with vinyl there is a balancing act with the two. With the CD there are no such limitational(except for level to a lesser extent). Now it depends on the sound you are going for. Getting rid of some of the sub bass (50hrz and lower)can often make the bottom end tighter and more focused.

    As always it depends on the mix and what a particular artist is going for. Some records now have much more sub bass than I am used to hearing.

    As a mastering engineer I try to find a balance between having enough weight in the low end without getting in the way of the clarity and punch of the overall mix.

    Joe Lambert
  6. wave

    wave Guest

    Hi Pass filters upset the mid and Hi band clarity of a mix imo.This obviously depends on the mix.I tend to prefer an extended lf response but it really depends on the quality of the low end. If I have a clear well defined low end extending below 40 hz and it works with the music I wanna feel it!
  7. brad

    brad Guest

  8. Masternfool

    Masternfool Active Member

    Dec 3, 2001
    While I have to use them quite often for making tracks match up, I would rather use them on the multitrack...My 2 cents
  9. John A

    John A Guest

    Originally posted by bassmac:
    Are hi-pass filters commonly used in mastering?

    I ask this because when I put a freq analyzer on many a commercial CD, it sure *looks* like there is.

    It looks like there is because experienced mixers roll of the low end off of lots of stuff during the mix. I'll roll down form 40 off the kick and bass, it usually tightens up the sound on most consumer systems. But there are some mastering engineers who I have seen work who will do a roll off, but if the mixer is good, its not neccessary.
  10. Ronny Morris

    Ronny Morris Guest

    What about rock that has 5 and 6 string bass players, Brad. The low B string, if the band is tuned to A-440 is 30.87Hz. That's if they are in common tuning, many rock bands tune down a half step, ala Stevie Ray Vaughan's technique and some tune down a whole step where the low B string is at 27.5Hz. Personally I don't like to roll off the lows, I want to take full advantage of the 20-20k that 44/16 offers, I feel the answer is keeping the lows in their proper space, "level wise" but not eliminating them all together. Granted FM radio doesn't have the range to reproduce 20-20k, but I have no problems with airplay, where the highs aren't rolled off. Some audiophile systems are going to reproduce well below 30Hz and how many clients these days ask for a market mix and a separate FM mix?
  11. brad

    brad Guest

  12. wave

    wave Guest

    Interesting point re singles /albums !
    I master singles differently to album masters.Lets face it singles are a maketing medium for some album and try to compete on radio tv etc.
    I will make a single hotter and with more mid / high than I might on the album (though not always!) It has to "compete" with other material.An album we try to make as a body of work if you know what I mean ! I try to work on the "quality" factor of an album, and "impact" on a single !
  13. Ronny Morris

    Ronny Morris Guest

    Understood. I'm not saying that I leave below 30Hz, on everything either, just that some apps benefit from not rolling off the low end.
  14. Studio B

    Studio B Guest

    I'm generally pretty aggressive with HP filters
    ( especially when I'm given mixes where I can see the speaker cones moving, yikes!). I don't know about you guys, but I prefer to use digital HP filters, even very high quality analog ones seem to have too much phase shift for my taste. Although occasionally that little warp can turn out to be a good thing. As always, it really just depends on the situation.
  15. realdynamix

    realdynamix Well-Known Member

    Feb 23, 2001
    Amen with that. Personally I am finding very useful information there, the sub harmonics tend to produce a rich bottom, on even an acoustic guitar, I beleve sub's are generated and contribute to that cone motion, and fullness. Of course, excessive use of this will tax any speaker, and amp. But, I find it an important part, the missing octave so to speak.

    The reason that it appears to be marginal, like on a spectrum, is the power that even small amounts contribute. If you need these frequencies, mastering may not allow successful control, if too many share this range, and a re-mix may be inevitable. The harmonic octave of a 20hz sound, can easily overcome what you are looking for in the sub, so reduction @40/60 is a must here, at least, on that particular instrument. As far as broadcast limiting, well, when it all goes digital someday, dynamic control won't be needed so badley. It will be more like the smooth juke boxes, with the real long release. The signals to be wary of are much lower, like 1 to 10 hz, digital cards can create these artificts, almost a dc component. Very very bad. So a rollof with a good filter here should live, if your cards produce these.
    Just tgif blabber, have a good weekend,
  16. errollem

    errollem Guest

    I use HP filters only when the bas is to muddy and over-rules the rest of the mix.
    With some compression on the low end you can fix
    the problem. well most of the time.

    I had a time ago a band who did their mastering
    in a expensive masteringplace. But on the end of the mastering session there was to much bass in the master. They asked this mastering comp. to fix that. They gave four reference cd's and still there was too much bass.

    They band came to me and they were right abought the bas.
    On the inlay of this reference cd of the mastering comp. I read what they did to remove the amount of bas. They used a low shelf for that. But it didn't work.

    The mix was not bad but the low end was not tide enough. This means that if you remove some low
    you lose some punch.
    I used for this session only the weiss dc1 and put a compression on the lowend with a treshhold of 25 so I had the possibility to have more control over the bas. It worked out very nicely.

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