Nah seriously, no one wants their mixes or audio-visual productions to sound substandard, so here are a few tips I hope will help to give them a bit of a hand up. Firstly, it's best if you don't have any flaws that need fixing by the time you get to the mixing, and then mastering phase of your project. Avoid the "fix in the mix" attitude. A well recorded song, voice-over, dialogue or foley is always going to sound better than one with poorly recorded audio, no matter how many "fixes" that you attempt to apply later. So try to use good quality equipment, good technique and good settings when you record. Aim to capture the full range of frequencies of a voice or instrument, as it is easier to attenuate them later than to try to add what is not there. You may decide you do not want to use EQ during the recording stage, but often using a high pass filter to remove unwanted low bass frequencies is a good idea when recording voice, cymbals or other instruments and sounds that don't need those deep bass frequencies. Hopefully you won't need to fix too many issues later, if things are done right at the source during recording. However, if any problems do emerge at the mix or post-production phase that you were unaware of before, try to fix them on a track by track basis, rather than attempting to fix them once you have a 2-track mix. The earlier you can deal with things that are potential difficulties the better. I will have a bit of a run through a few of the potential hazards that might trip up and give you some tips to help alleviate them.
DC Offset
Cheap sound cards or recorder inputs often add a DC voltage offset to a recorded sound. There are sometimes other factors that can cause this as well. It is at 0 Hz, which we can't actually hear, but it offsets the wave so that it is centered above the zero line. This means you have less headroom before clipping occurs. Another thing that may make DC offset an issue is when doing cuts and edits, even in an apparently silent passage you may get clicks or pops at the beginnings and ends of edits. Check out your tracks, and if they look like the wave is not centered around the zero, then you need to filter it. Or if when you were recording, the meters were reading something even when you were not sending them any signal: that may be a giveaway. Most recording programs have a function called something like "remove DC offset". Use it if the problem is evident. Or filter out everything below 10Hz. Do this prior to any compression or EQ'ing. It should get rid of any offset.
Hums and Buzzes
It is very easy to get hums and buzzes in your audio, especially from things like guitar amps. Try to avoid them during the recording process. Check your cables, experiment with different proximities and angles of the guitar in relation to the amp. Use balanced cables where possible, and avoid long runs of unbalanced cables. Also try to avoid having power cables and transformers near audio cables. Keep them at least a foot (30 cm) apart, and if they must cross, try to do it at right angles, and better still sit the power cable on something above the audio cables so they don't touch. Hums can be dealt with by some programmes and plugins such as The Waves X-Hum, but it is very difficult to remove buzzes from a recording.
Hiss and white Noise
Hiss is often a result of incorrect gain settings when recording. Maybe you had too small a signal, and the gain set too high. Perhaps you just have a noisy piece of equipment. Whatever the cause, use your de-noiser, de-hisser or noise removal plug-in, or program function before you compress or otherwise tamper with the audio. If you compress before you use noise removal, you will likely be boosting the noise along with the signal, but if you remove the noise first, the compressor won't find any noise to boost! Higher settings on these programs or gadgets often seriously mess with the signal and change the tone considerably. Try to avoid using them if at all possible, try mild settings first
Clicks and crackles
These problems can be a real bane of digital recordings at times. Some suggestions I can offer in avoiding them are as follows:
Defragment your hard drives to ensure the computer runs fast enough to keep up with the demands.
Adjust your program's buffers to avoid clicks
Use the latest drivers for your software
Use cross fades at edit points
Avoid clipping any equipments inputs while recording
If you are unfortunate enough to get clicks in your mixes, use your program's or plug-in de-clicker, but try to get as close to the area of the waveform as possible by cutting the region either side of the problem area, and selecting just that small area of the region for processing. Sometimes you can manually remove clicks by re-drawing a wave, with the pencil tool supplied in the software.
Using a de-esser
Here is a useful tip I discovered a while back. Sometimes I found it hard to get enough headroom in my vocal recordings to cut through a mix. There would often be short unexpected transient peaks that would shoot way above the rest of the signal, and into the red zone. Now, I could have used a compressor or a brick wall limiter to squash these hard, but I discovered that they are often just centered around one frequency band, and most likely in the 6-8 khz range where the sibilance of an "S" sound resides. By using a de-esser, I not only made the "S" sounds less harsh, and more pleasing to the ear, but I found I now had much less problem with the transient peaks, and was able to boost the level of the vocals up more before clipping occurred. Kind of like killing two birds with one stone.
This technique is not only limited to vocals either, but frequency dependent compression using a side chain or a de-esser can also be applied the same way to such instruments as an acoustic guitar.
Well I hope these tips are of some use to you in the mixing, mastering or post-production process. Have fun with your audio! .
Rocksure Soundz
(c)April 2011
