Question: Why is a well configured and “tuned” sound system important for a live performance?
Answer: You can use the latest, greatest microphones and preamps in the market but if your overall sound system is not properly configured, you may have feedback issues, bad sound imaging, and overall bad sound. While sound system configuration and tuning is a pretty in-depth topic, we will look at the overall concept as well as some helpful information from some of the best system engineers on the road today. Note, configuration and tuning are not things you will learn from one quick training session or, even more so, from this blog post, but since they play such a vital role in producing good, quality audio, you will want to learn all you can in order to improve as an audio engineer. Like most things in audio, you may have to spend time practicing and growing with each new experience to master your skill sets.
While “tuning” a sound system may mean different things to different people, there are a few common tools we can use to best set up the system. A simple, cost-effective tool is an equalizer filter, and while parametric and graphic equalizers each have their strengths and weaknesses, they can both be used in the tuning process. Advanced sound systems in installations and large performing venues utilize more advanced DSP (Digital Signal Processing). Another tool used in sound system tuning are measurement microphones to accurately capture the sound in the room, and measurement software, such as dual-channel FFT analyzers, are used to capture an impulse response of the space, and read, measure, and evaluate the audio for further testing. There is a lot of trial and error when tuning a sound system, but it is good to follow the 80/20 rule: In dealing with the audio and physics of tuning sound systems, if you can get 80% of speaker coverage and good sounding audio, the room may be usable and considered “tuned.” Again, there are many schools of thought on sound system tuning.
The overall theory behind tuning your sound system is to level the playing field, per se, allowing you to mix without having to work around issues created by room acoustics. With acoustics, when sound hits a hard surface, the sound bounces around and is deflected in different angles causing sounds to reach a listener at different times. This may cause phase cancelling issues and alter the sound, and is often why every listener has a different experience of the mix. Architecture is often angled to improve the acoustics of a particular space and thus enhance the listening experience. When designing a space, one should consider the materials, angles, and overall design that will lead to the best acoustics. Most times when you come into a space, the architecture and acoustics step will have long since been taken care of, and what remains is to choose the optimal placement of speakers. If audio engineers and acousticians are brought into the preplanning process, your changes of a successful outcome jump exponentially. Once all that setup is completed, the actual “tuning” of the sound system can begin.
DSP devices can offer a variety of audio filtering tools such as equalizers, delay filters, dynamic filters, and crossovers, which allow you to distinguish which frequencies go to your sub speakers and which frequencies go to your main speakers. Other filters may be used – usually early in your DSP signal chain – to specifically “fix” speakers. While speaker manufacturers offer frequency graph readouts for their products, you may want to test your speaker to ensure the graph is accurate. Conducting these tests will help when you are using multiple speakers, ensuring that they will perform well together. For example, if one speaker is wired incorrectly, it may perform out of phase with another, and if this is not caught early in your tuning process, you may be chasing your tail later in the process. Once your speakers are tested, you may add IIR and FIR filters into your DSP to make “corrections” for a more neutral and flattened audio response. Other EQ filters may be used to help with acoustical artifacts that may arise once the “corrected” speakers are firing into a space. These EQ filters may help reduce room modes, standing waves, room resonant frequencies, or boundary interferences caused by acoustics.
Having read this, you may now have even more questions, which is great – it means you’re curious to dig deeper into the important issue of sound system tuning and learn how to effectively go about the process. There are many online and in-person training sessions available from great companies such as SynAudCon. This blog post may have taken you just a few minutes to read, but these training sessions are multi-day events that give you in-depth instruction in sound system tuning. Again, whether you are a hobby audio engineer, AV integrator, national touring audio engineer, or just someone who likes to learn more about audio, spending time learning the theory behind audio and sound system tuning can really be beneficial. It takes time and practice, but the reward is having a properly tuned sound system that produces great audio.
If you have other questions related to audio and the use of Audio-Technica products, please contact the Audio Solutions Department.