The Audio File: Speaker Sense

How Loud?

How loud is loud enough? How loud is too loud? Historically, these questions have been answered by musicians themselves, balancing the capabilities of their instruments and voices to fit the size and ambient noise level of the spaces in which they performed, in order to best convey the dynamic contrasts expressed in the written score. However, a multitude of interrelated factors complicate matters considerably when we attempt to address this issue as it relates to the amplified reproduction of music in the home.

An oft-repeated chestnut from the realm of hi-fi lore holds that for every recording, there is one "correct" playback level (for a given audio system in a specific listening room). The principle tenet underlying this contention is simply the purist notion of "real" high fidelity: an audio reproduction system should ideally replicate the sound captured by the microphones in the recording venue, at exactly the volume level at the microphone locations. Unfortunately, while objective measurement of sound pressure level (SPL) at a particular point in space is easily accomplished, human perception of "loudness" involves substantial cognitive processing of multiple auditory cues, including SPL, reflection density, the decay signature of reverberant sound, the dimensional volume of the performance space, the number of musicians in the performance ensemble, and even the tonal and dynamic characteristics of the music itself.

Many listeners are surprised to learn how quiet a typical symphonic concert actually is, regardless of the location of their seats in the hall. On the other hand, the perceived loudness experienced by the musicians on stage is much higher than typical home-stereo playback levels: imagine standing a few feet in front of a half-dozen trumpets and trombones playing triple-forte!

Given these divergent perspectives on the musical event, isn't the notion of a "correct" loudness level a fundamentally bankrupt concept? Well no, not really. Our salvation comes from the very act of RECORDING the music itself. If a recording engineer places the microphones directly at the conductor's podium, obviously the sound that is captured will differ substantially from that of a recording made with the microphones suspended fifteen feet above the seats in the tenth row. Similarly, the sound of a solo soprano "close-miked" in a small recording booth will exhibit a vastly different character than that of the same soprano singing in a medieval cathedral, captured by microphones forty feet away.

Thus it is important to respect the intentions of the recording itself when setting playback levels in our homes. In general, most classical music performances are recorded using techniques expressly optimized for achieving realistic reproduction in nominally-sized domestic environments. Well-done recordings, whether, mono, stereo, or multi-channel, succeed precisely because they convey the "essence" of hearing a specific performance in a specific venue, through the interpretive filter of the recording engineer's choices. I cannot emphasize enough the significance of that last element: our audio systems cannot ever reproduce "the absolute sound" of unamplified acoustic instruments; they can only play RECORDINGS of said music, recordings which intrinsically and incontrovertibly alter how that music is presented to our ears.

We must therefore take our cues for setting playback levels from those recordings themselves, informed by our personal experience listening to live music, the limitations of our playback systems and rooms, and of course our own taste, to the limited degree that individual discretion is consonant with the perspective of the recording. For example, my stereo certainly has "enough watts" to play a guitar sonata at a ludicrously loud level, well in excess of anything remotely resembling natural sound. Fortunately, its low-level resolving ability is also sufficiently adept at conveying the subtleties of dynamic inflection that I can play that guitar sonata at a loudness level appropriate to the actual instrument. The choices made by the recording engineer ultimately determine whether the final sound that I achieve either brings that guitar into my listening room, or transports me to the room in which the guitar was recorded.

Obviously, a full orchestral ensemble arranged for a performance of Mahler's Sixth Symphony cannot conceptually "fit" into a typical domestic listening room. Fortunately, the auditory perspective built-in to our recordings saves us once again. By paying attention to the dynamic structure, tonal balance, and spatial characteristics endemic to a given recording, you can glean the producer's intended perspective. A mellow, lush, distant, reverberant recording calls for a lower playback level consistent with what we would hear from that perspective in a live setting. Conversely, a drier, brighter, more up-front recording may require a louder playback level in order to best reproduce the intensity and energy that such a recording style is intended to convey. The question of whether or not the engineer's choices suit either the piece at hand or the artist's interpretation is not something we can address here, obviously.

In all these instances, try to avoid falling into the trap of attempting to compensate for limitations in your recordings, audio system, or listening room by playing music at inappropriate levels. If you play the Witches' Sabbath movement of Berlioz's Symphonie fantastique at an inappropriately quiet background-music level, you'll lose much of the intended impact, as well as the natural tonal colors and instrumental balances called for in the score. Alternatively, if you play that demanding movement too loudly because your equipment lacks refinement or resolution, you'll run the risk of electrically over-driving your amplifier and loudspeakers, or acoustically over-driving your listening room, either of which will generate fatiguing distortion artifacts that can substantially impair your ability to connect with the music itself.

Too many listeners either truly believe or cling to a hope that all of those little knobs and buttons should be set once and for all time. Yes, it may be a pain to listen for a few moments to each individual recording, fiddle with the controls to achieve the finest playback level, and then start the piece over again from the beginning. But if you familiarize yourself with the recording characteristics of your favorite performances, paying a few minutes of attention to the cues built into those recordings, and adjust the playback level of your audio system accordingly, you'll quickly learn to set the stage for a more natural, involving, and rewarding listening experience.