Mastering With Samplitude
- 1. Magix Samplitude Producer 2496 Version 6 Part I Mastering with Samplitude Copyright 2001 by Martin Naef From a Stereo Mix to the CD Have you ever wondered why professional records sound a lot louder than what you get at home after hours of mixing? Did you too want that last bit of transparency on your CD? Well, you do not need magic, but a final stage in the production pipeline might do the trick. That last stage between the final mixdown of your tracks and burning the CD is called mastering. What is Mastering There are a lot of rumors about the magic of mastering travelling in the heads of hobby musicians, revolving around super-expensive analog equipment and top- secret wonder-tools. On the other hand, there is overly simplistic advertisement for mastering software and hardware that claim to provide instantaneous professional results. The truth, as usual, lies somewhere in-between. From a purely technical point of view, mastering consists of equalization, dynamics, ste-reo width processing, sometimes tube or band saturation and finally limiting and some digital processing such as sample rate conversion and dithering to fit the target media. Other ingredients include a place with carefully optimized acoustic properties and first class speakers, a lot of experience and a pair of fresh ears. The latter is often underesti-mated: mastering is like getting a second opinion.
- 2. A professional will never master his or her own mixes. While it would be nice to have enough budget to hand the mastering over to a profes-sional with years of experience and all the nice expensive gear, many hobby musicians still do it themselves more or less successfully. The key is to have the right tools, know them well and allow yourself enough time between finishing the mix and starting the mastering (we are talking days or weeks here) to gain some distance. You should also “calibrate” your ears by listening to a lot of records which you consider references in the same environment where you do the mastering. It is of course always a good idea to have a friend do the mastering instead. Things to Consider Before you even start thinking about mastering, consider the “garbage in - garbage out” principle: If the source material is bad, the end result will be too. Make sure, your mix sounds good in the first place. Mastering can improve things, but it doesn’t do wonders. Once your mix is well balanced, make sure you record it carefully: Keep the noise level low by muting unused channels, keep the signal hot but avoid clipping at all cost. Do not try to push the sum with EQs, compressors and limiters at this time. Also, fades are best done after mastering as they might no longer exhibit the same behavior after gating and compression is applied. Now that we have a clean recording, we can finally start the mastering process. The Tools Essential tools for mastering are a good wave editor, a high quality fully parametric equalizer, dynamics processor (preferably multi-band) and a limiter. To support your ears, a set of metering and analysis tools are essential too. Stereo width control and tape saturation simulations also help, but you can do without. All these tools are available in many different flavours and quality levels, from
- 3. traditional outboard gear (often expen-sive) to plug-ins for the various editing platforms and also as “all-in-one” solutions. The selection depends mainly on your taste and budget. In this article, I will use Magix Samplitude Producer 2496 Version 6 to illustrate all tasks. Samplitude, formerly distributed by Sek’d, has an excellent reputation among audio professionals. Many say it is the best digital audio workstation software available. Besides plenty of wave editing features which I will not discuss in this article, it includes all necessary tools for mastering, including CD-burning. There are several versions of Samplitude available (see www.magix.com for details). The small “Master” edition is especially interesting for hobby musicians who want to master CDs since it provides all necessary tools at a very affordable price. Metering The ear is always the final judge. Whenever you adjust parameters, you have to trust your ears to reach the desired effect. Yet, the eye can support the work of an audio engineer a lot. Samplitude provides an extensive set of metering tools. They all visualize different aspects of the audio signal. The classic power meter for example displays the strength of the signal. You can optionally include the mean power level (as opposed to the peak sig-nal) and minimum and maximum values. The frequency analyzer (spectrometer) is also a very helpful tool. It visualizes the
- 4. power-distribution in the frequency domain. This lets you easily spot regions where you have too much or too little power and therefore helps adjusting equalizers and multi-band compressors. You can of course adjust the granularity of the analysis and many other parameters such as hold time for the peak marks. The spectrograph is similar to the spectrometer, however it prints the values of the frequency bands over time. It is a bit harder to read than the spectrometer, but it shows more than just the current status and therefore allows a more detailed analysis over time. The phase correlation meter lets you spot problems in your stereo panorama. If you only get a vertical line, your source signal is actually a (perfectly boring) mono signal. If it shows a very wide distribution, it means you get a very broad stereo
- 5. spectrum, and probably a very bad sound if listened on a mono system (such as many TVs) because the two channels may cancel each other out. The correlation meter also reveals an uneven left/right panorama. The oscilloscope finally is a tool that I never found really useful, but it looks cool... All these visualizations are highly configurable, including peak hold times, frequency and power ranges, peak vs. average vs. power analysis and of course colors settings. Admittedly, all these visualization tools are not an absolute necessity if you have well trained ears. But there is no reason why you should make your life harder than neces-sary, right? Equalizer Once you know what your frequency spectrum looks like and have an idea how you want it to be, an equalizer is the tool to get there. With an equalizer you can
- 6. increase or decrease a certain frequency band, specified by a center frequency and a Q factor (width). For the lowest and highest band, you can switch the type between peaking, shelving and high/low-pass characteristic. In the example below, I attenuated some of the lowest frequencies because they can not be heard on the typical cheap hi-fi set anyway, compensated that with a peak in the 120 Hz region though. I then added some power in the presence region (around 3 kHz) and slightly increased the high frequencies above 10 kHz. The graphical representation of the frequency response helps understanding the process better, especially when used together with a spectrograph visualization. If you need drastic or very fine grained control over the frequency spectrum, Samplitude provides a unique tool called FFT Filter. FFT stands for Fast Fourier Transform, which is a two-way transformation from the time into the frequency domain and back. This fil-ter extracts the full frequency spectrum information from the incoming signal and mod-ifies it according to the settings. With the FFT filter you can for example precisely filter out a certain frequency band (say a
- 7. 50 Hz hum coming from a leaky power line) as in the first example or heavily filter the spectrum (the spectrum shown represents a piano note) for creative sound design. You will rarely use the latter type for mastering pur-poses unless you have to do heavy restoration work on old and low-quality records. The equalizers in Samplitude are clean and get the job done pretty well.
- 8. They are a bit on the “analytic” side. If you want to add some “analog” warmth to your recording, you might consider buying an additional EQ plug-in such as the Waves Renaissance EQ or the Timeworks equalizers. But be aware, additional plug-in bundles that can compete with the Samplitude algorithms easily cost as much as the full Samplitude package. Dynamics In WindoWatch issue 3/99 I explained dynamics processing in detail, presenting the Cakewalk FX 1 bundle. Dynamic processing is used to modify the dynamic range of music, such as cutting of loud peaks and getting silent parts more into the foreground. On the sum, dynamics are often used to make the piece slightly more “compact”, add a slight “analog” feeling or to push up the perceived loudness. While somewhat weak and cheap dynamic processors on the individual signals, they may be sufficient for many tasks. You should be very careful with dynamic processing on the sum. Typical artefacts such as lack of presence or even pumping destroy the best mix easily.
- 9. Samplitude includes three dynamics modules. A simple compressor, expander gate and limiter combination without a lot of bells and whistles, the advanced dynamics module and a multi-band compressor. For mastering, you will typically use only the last two. The advanced dynamics processor is a high-quality compressor with selectable charac-teristics. The analysis can look at the signal peak, average power (RMS) or just the absolute value in the “fast” mode. Preview mode allows look ahead and therefore adjust the gain already before a peak occurs, leading to a more balanced (but less punchy) result. Previewing is especially important for the limiter section as it allows to cut the signal to the maximum allowed for the target medium without audible distortion. The other options in this module are pretty much standard and easy to understand. I liked the option for variable softness of the knee characteristics. The competition usu-ally offers only a small selection of values, not a continuous slider. Full-band compressors often cause problems in the sum when a strong bass pushes the rest away, leading to audible pumping and a loss of presence. Multi-band dynamics solve this problem by cutting the frequency spectrum into up to four
- 10. bands which are then processed individually. Each band has the full set of compression parameters. The parameters can either be linked (all bands have the same settings) or adjusted individu-ally for more control. The crossover frequencies and characteristic can also be set. In practice, multi-band dynamics means for example you can compress the bass region without affecting the mid and high bands. You can also regard multi-band dynamics as a “dynamic equalizer”. The combination of the multi-band dynamics module and the limiter in the advanced dynamics module make a strong couple for making the mix appear loud without adding audible distortion. The quest for loudness might not always be in the best interest of the music, but if you target the dance floor, a loud mix is absolutely essential. If you do not follow this trend, your mixes will often be perceived as “home-brewn”. Samplitude pro-vides the tools needed to follow this trend, and they can compete with most of the dedi-cated mastering plug-ins and even hardware. Stereo Processing
- 11. Placing instruments in the stereo panorama is a very important act during the mixing phase. Careful panning gives the mix a lot more space and allows to position the impor-tant things in the center without completely pushing away the other instruments in a similar frequency spectrum. During the mastering stage, there is no longer that much you can do about stereo pan-orama. Yet, a good stereo processor can fix some minor errors or widen up the mix. Samplitude includes a multi-band stereo enhancer which allows treatment of stereo width and position for three bands independently. The bass band will usually be concen-trated in the middle (low frequencies can not be located well by the human ear) which gets rid of phasing problems. Mid and high bands however can be widened or posi-tioned in the panorama if the mix has some flaws there. As a nice detail, the phase corr-elator visualization can be opened right from the enhancer tool. Denoiser
- 12. Recordings are not always perfect, so once in a while there will be the need for noise removal or other restoration tasks. Samplitude includes an excellent denoiser tool which is highly configurable. Probably the most powerful feature is that it can take a selected region which is supposed to be silent, analyze the noise there and then use this informa-tion to reduce noise across the full wave file with minimal impact on the original data. Be aware though: Every noise reduction process also removes parts of the musical data. Many instruments like flutes or a snares include a lot of noise as part of their tonal char-acteristics. In the final recording, a little bit of noise is often less disturbing than the arti-facts from an aggressive noise removal process. Other tools such as dehisser and a declipper are available too. Samplitude Signal Flow Up to now, I have talked a lot about the different mastering tools and when to use them. However, I did not tell where and in what order they are applied.
- 13. Samplitude knows the concept of wave projects and virtual projects. As the name sug-gests, a wave project works on a single wave file. Modifications can be done both destructive and non-destructive. Several wave projects (objects) can be placed in a track of a so-called virtual project. Every object has its own set of effects and settings. They are edited with the “object editor”. The effects in the object editor are not applied destructively, instead they are calculated on the fly during playback. The signal is then fed into the mixer section, first through the track and from there into the master section. The mastering effects are again avail-able here in a non-destructive way. When mastering a complete
- 14. CD, you will typically want to have the settings per object, as there are very few situations where “one size fits all” leads to good results. Candidates for the master section are the limiter and dithering tools (if you do not want to rely on the dithering provided by Samplitude). As an impor-tant difference, the order of the mastering effects can be changed in the Mixer section, whereas they are fixed in the object editor. In addition to the non-destructive effects, Samplitude provides all effects as offline wave-editing processes in the Effects menu. Some calculation intensive effects such as the high-quality FFT-analyzer and filter or the denoiser are only available there. CD-Burning Once you are finished with parameter tweaking and mixing, all tracks are laid in the cor-rect order with nice cross-fades, the time is ready to burn the CD. One nice thing about Samplitude is the integrated CD burning tool. You do not need to export the data to a special burning application, instead you can directly set the track markers, indices and pauses in the virtual project. A few automation options make setting the initial markers a breeze. You can then move the markers to suit your needs either with the mouse or with the CD index dialog.
- 15. Samplitude fully supports Red Book standards. Details like CD text, ISRC and UPC/ EAN codes, preemphasis and copy protection bits are configurable. Even generating hidden tracks and other funny stuff is possible with Samplitude. Anybody asked for pro-fessional CD master burning? Check out Samplitude! Is that all? The tools I have presented make a pretty nice mastering package. Considering the excel-lent quality of the processing tools and the high-end CD mastering capabilities, the price of Samplitude is more than justified. But that is not all, Samplitude offers a lot more functionality, including sophisticated wave editing, multi-track arranging (only Studio and Producer versions), recording and even 5.1 surround mastering (Producer only). MPEG, Windows Media, Real and AIF formats are imported and exported with great flexibility, making Samplitude the single tool for audio processing you really need. Martin has warned me that there is more coming about this application. He is well known for his graphics presentations as well as his long interest in music composition. We look forward to the next article.