There is a reason the top mastering engineers are able to refine tracks and albums to sound gloriously big, full, spacious, and lively on the finest high-fidelity playback systems. They take care of the room acoustics as a matter of course and create a sonic setting which closely resembles a well-designed HiFi room.
Engineers: are you having trouble “polishing” those songs after the mix is done? Think like a HiFi listener!
HiFi guys and gals: have you lost the crisp sound stage and big, clean sound you had in your old room? Think like a mastering engineer!
Whichever camp you fall into, read on…
Overcoming the Noise Floor
Often room reflections are so loud and numerous they collectively sound louder than the original direct signal and act to drown out the nearly perfect direct sound. And so the last link in the audio chain is the also the weakest link in the audio chain….. the Playback Room.
The electronic “hiss” noise floor was a problem in audio for many years. Improvements in signal processing have driven the electronic noise floor down to almost the threshold of hearing. The noise floor now is more mechanical – transport decks, air conditioning and outside noise intrusion.
But there is one less obvious noise floor and it is currently the single most significant sound barrier to better listening. It is the self noise of the listening room acoustic. Lingering sounds from one musical moment become the masking noise floor for the next musical moment.
The chain is as strong as its weakest link and for today’s audio, the weakest link is the listening room acoustic.
The listening footprint varies with personal taste and room size but generally is an isosceles triangle with the speakers located at the two corners of the short side of the triangle (b) and the listener set back, a further distance (h) at the vertex. The base of the triangle identifies the plane of the speakers. Commonly, speakers are 7 to 8 feet apart and the listening position is set back about 10 feet from the plane of the speakers.
The overall goal is to minimize the plethora of room reflections so that the direct sound from the speakers can be clearly heard within the context of an ongoing and evolving ambience which is comprised of the reverberation and reflections of those sounds most recently played.
Broadband Acoustic Control
Kinetic absorption + lateral diffusion controls the treble range
Pressure-zone corner trapping controls the musical bass range
Structural damping controls subwoofer bass
The Musical Range
The process of converting a relatively empty sounding listening room into a high-performance critical audio room can seem complicated, but the techniques which yield amazing listening performance have been developed. Once the pattern of sound reflections has been cut back and sculpted into a quiet and complimentary running ambience, the last link of the audio chain becomes as strong as the rest.