Voicing our rooms is a process that involves science, time, and art. We use science to get the technical parts of our room under control. We measure frequency response, room modes, reverberation times, and a host of other variables to try and make our rooms acoustically as accurate as we can. Once we have all the technical issues managed the best we can, we must use our rooms over time and live with them sonically to see what changes we need or want to make. It is these changes that we make after the technical stuff has been addressed, that produces the art of voicing.
Low Frequency First
The technical issues that we must address begin and end with low frequency control. We must have bass right or we will never be really happy with our rooms. Bass issues must be managed and reduced to a point where they do not interfere with our middle and high frequencies. Low frequency issues must be minimized so that they are reduced to a nuisance and not a problem. Low frequency issues in small room acoustics are like a chronic disease, we never control them a 100%, we just try and manage them without having a real cure.
Use Power To Manage Power
We must use powerful absorbing technologies to manage bass resonances within our room. Foams do not work for frequencies below 100 Hz. One would need foam 11′ thick to completely absorb a 100 Hz. wave and that is only 100 cycles. Do not be misled by manufactures claims that they put on their products. Manufacturers use the term bass absorber incorrectly and their claims are misleading to the uninformed.
One really never absorbs bass energy completely as their claims go. All we can do in small room acoustics is manage bass energy, absorbing all of it is impossible and unrealistic. We can reduce the pressure created by low frequency waves by absorbing part of the wavelengths energy, but large amounts of low frequency absorption must be designed for using only one time tested and proven methodology termed diaphragmatic absorption. Only diaphragmatic absorption has the design capabilities to reach low frequency energy with the necessary rates and levels of absorption capacity. The downside is that a diaphragmatic absorber is heavy and expensive to build correctly.
Our middle and high frequencies can be managed more easily than our low frequencies. However, we must pay particular attention to how we manage them in small room acoustic situations. Middle and high frequencies represent the emotional content of our music and we must use care not to over treat them with absorption or diffusion technologies. If we are using absorption to tame middle and high frequency reflections, we must do it in a way that does not rob the essence from our signal. We must not over absorb and loose precious middle and high frequency energy for the purposes of controlling it at our mixing or monitoring positions.
Diffusion is another way to control reflections from our room boundary surfaces. Diffusion takes the reflection and sends the energy back into the room spread out into smaller reflections if you will. Diffusion does all of this without any loss of energy. One must choose the correct diffusor for the particular room boundary surface in the room. Diffusion is a popular room treatment for rear walls because rear wall reflections bounce back to our monitoring or listening position and confuse the direct energy from our monitors or speakers. Diffusion is also a popular treatment for ceilings.
Time Is On Our Side
With all of these tools at our disposal, the next element we need to use is time. Time spent in our rooms will help us hear the real room sound after the scientific variables have been met. Only time spent using different music sources in our rooms will produce the issues that we still need to resolve. We will get to know the sound of our room and what we like or don’t like about that sound. We will hear the attack and decay of individual notes and realize that we need more of this or that acoustical treatment to address the issue. Sometimes we will hear an issue and sometimes we will not. Only time spent will help us tune the room in the way we want it to sound.
The art side of room voicing has to do with materials we use inside of our rooms. Different material types have different sounds. Wood has a good warm sound. Glass has a harsh bright sound. Material choice is critical to our fine tuning voicing process. The best sounding rooms I have been in are a balance of natural materials. There is a balance between fabric which is soft material and stone or rock which is a hard material.
Turn To Nature
Soft materials must not be too soft that they drain the life out of our signal and hard material types must not be too hard that they cause their own set of issues. We need the strength the harder materials afford us for low frequency control but we also need the soft caress of fabrics inside our rooms to minimize reflections at our listening or monitoring positions. A proper balance of natural materials will produce a warm and pleasing room sound. It takes many attempts using different material types to achieve the room sound one desires.
Room voicing takes time and energy. Once the scientific basics have been satisfied, we must voice or tune the room just like a singer or instrumentalist tunes his instrument. We must try different material types and stay focused on using natural materials within our rooms. Finding the necessary balance of natural materials is the process and the journey. Just when we think we have our rooms the way we want them, the humidity level rises and our room does not sound the same. Oh well, back to science, once again.