Brightness controls the degree that the echoes will overlap. Effect Level controls the volume level of the echoes (but not the original audio).
Effect Mix allows you to mix the echoing audio with the original in order to better blend it in. This is one of the lesser-used filters FCP provides. A DC Notch filter will remove the DC offset component which you probably need a degree in audio engineering to fully understand. Sometimes you may experience a DC current leakage through the mic, causing noise in the recorded audio. Be aware that very loud sounds could still theoretically peak.įinally, it is also worth mentioning that the compressor reduces the volume difference between the subject and any background noise, so background noise will be more noticeable upon boosting the audio after applying the compressor. It is worth noting that the compressor lowers the volume of sounds above the threshold but does not necessarily reduce them to a value at or below the threshold. If the ratio is set to 2 (2:1), then a 10 dB increase in volume above the threshold will be halved to a 5 dB increase. Ratio tells the compressor by how much it should reduce the volume when a sound exceeds the threshold. Setting the threshold to just under your preferred limit allows time for the compressor to lower the volume in anticipation for a louder sound once the threshold is reached. This is something inherited from live audio mixing where you don't know what's coming next. Higher values allow for a smoother and less noticeable response but set them too high and the compressor won't respond quickly enough. Release time refers to the time taken for the filter to increase the volume again once the high amplitude frequency has finished playing. Attack time refers to the time it takes for the filter to decrease the volume once it has detected a frequency with an amplitude above its threshold. Obviously this reduces the volume of the overall audio so Preserve Volume rectifies this (although I find it is often then too loud). This is a useful way of minimizing the difference between two subjects talking at different volumes or making sure that the audio fits within the limits of the playback device. The Compressor / Limiter reduces the volume of sounds above the threshold amplitude. If you don't understand the above explanation just play it by ear or use the AUBandpass filter. If you want to find out the bandwidth, just divide the center frequency by Q. It is worth noting that Q is not the bandwidth itself but it is related to it. when the bandwidth goes up, Q goes down by a proportional amount). There are numerous articles about it on the internet that get quite technical but all you need to know is that it's the relationship between the center frequency and the bandwidth (f/b) so Q is inversely proportional to the bandwidth (i.e. Q stands for Quality Factor and is a different way of representing the bandwidth. This is identical to the AUBandpass filter (in the Apple folder) except that instead of the bandwidth parameter, it has a mysterious one called Q. This will allow a range of frequencies on either side of the center frequency to pass through and reduce (attenuate) frequencies outside this range. This is useful when you need to boost the bass of a voice or improve a flat-sounding voice. I personally prefer AUFilter (in the Apple folder) because it gives you a bit more control and allows you to adjust 5 bands. This allows you to take three separate bands (low, med and high) and adjust the gain up and down individually. I would generally advise you to pick the built-in filters over the Audio Units whenever possible, as they tend to use up fewer system resources. So which should you use? Well, for a start, bear in mind that some of those filters have the same function but different parameters. Now, one thing you may have noticed is that there are often duplicate filters such as AUBandpass (an Audio Unit) and the built-in Band Pass Filter.
It is worth mentioning at this point that this guide is intended for users of Final Cut Pro 6. This guide is intended to inform Final Cut Pro users of the options available to them for fixing bad sound. This part will cover the audio filters that ship as part of Final Cut Pro.
Part 1 covered the Audio Units that ship with Mac OS X and is available here. Final Cut Pro Audio Filter Guide Part 2This is the second part of the Final Cut Pro Audio Filter Guide.