most of the tracks have been close-miked or recorded with no consideration for what the mix might require . A lot of young guitarists , who work on their guitar sounds at home in their bedroom , create these amazingly massive sounds that take full advantage of the low , mid , and high-frequency ranges . Admittedly , they probably sound great at the time ; however , if the electric guitar fills up the mix , it ’ ll conflict with the other low-frequency instruments and aid in the creation of a muddy mix .
Vocal tracks can even have a lot of conflicting low-frequency content that not only competes with the other instruments to build a thick muddy sound , but also results in lyrics that are next to impossible to understand . I could go through all of the possible instruments , but I imagine you ’ ve already heard my point . Too many instruments occupying the lowest frequencies is a recipe for a bad mix .
High-pass filter to the rescue ! Use a high-pass filter to trim out unnecessary low frequencies on every track whose musical personality doesn ’ t require them . Listen to the track while you raise the cut-off frequency . There will a specific frequency where the instrument just starts to sound uncharacteristically thin . Find that spot and back the filter down just a little so the instrument or voice sounds full , clean , and perfect for the mix .
This technique works very well when mixing recorded tracks because it eliminates excessive low-frequency energy that will most certainly result in elevated mix levels that are likely to make your mixes sound quieter than the rest of the kids on the block . In addition , using highpass filters in a live sound setting , or when mixing a live-tracked song , performs a couple key functions : 1 . It cleans up the low end amazingly well , resulting in a mix that has increased impact and power
2 . It decreases problematic leakage from the rest of the band . Stage rumble , drum leakage , loud guitars , and horns find their way into all of the mics on stage . Listen
The high-pass filter lets the high frequencies , above the cut-off frequency , pass through unaffected , therefore cutting the low frequencies .
as you raise the high-pass filter cut-off frequency and take note of the leakage that ’ s eliminated - it ’ s quite extreme in most cases .
HOW HIGH TO PASS The cut-off frequency is easy to find by ear . Listen as you sweep the filter up until you start to infringe on the real sound of the instrument . Here are some informational suggestions ; but , there is no replacement for using your ears to guide your choices :
• Kick drum doesn ’ t need to be trimmed much but setting the slope to about -24 dB per octave and removing everything below about 30 – 50 Hz helps make sure there aren ’ t any super-low frequencies causing a level problem .
• Bass guitar can be thinned out below about 30 Hz , too .
• Acoustic guitar is a wide-band instrument with ample lows and highs ; however , its function in the mix doesn ’ t require many lows . Depending on the musical part , size of guitar , and orchestration , use a -24 dB / octave slope and sweep the filter frequency up to somewhere between about 150 Hz and 300 Hz , or so . Use your ears to help find the perfect cut-off frequency .
• Electric guitar can be treated like acoustic guitar in some cases ; but , where the electric guitar part is all about power chords and structured tutti licks , it might be important to keep all of the low end you can get , especially if the bass and kick drum are more focused on the attack component .
• Close-miked vocals often sound very thick . A high-pass filter helps clean up the vocal sound and eliminate unwanted lowfrequency leakage . Sweep a -24 dB / octave slope up to somewhere between 150 and 300 Hz . The exact filter frequency depends
on the vocalist ’ s timbre and the musical style .
SPECTROGRAM Paying close attention to the kick drum and bass guitar sounds , and shaping them to work together , is an important part of the creation of a powerful musical mix . In addition , high-pass filters are extremely effective anytime you ’ re managing the lows in a mix . Another very useful tool is the spectrogram , which provides a visual analasys of the mix energy from the lowest to highest frequencies . The strongest amplitudes are from orange to near white . The weakest amplitudes tend to register more in darker shades of orange and blue .
Spectrogram plug-ins are relatively common , and they can be very helpful because they let you see whether the mix is overloaded in the low-frequency band . iZotope has a powerful audio analysis plug-in that contains a spectrogram , plus their RX mastering tool provides an excellent visual spectrogram .
The goal , in using these tools , is to see the low