A plus or minus 5 dB loudspeaker deviation goes unnoticed without a direct reference

Evidence

Deviations from a flat magnitude response within the audio range of 20 Hz–20 kHz change the perceived ‘colour’ or timbre of sound (Toole, 1986). However, close to the upper and lower frequency limits, the response flatness is less critical than in the mid-frequency range. The magnitude response of the loudspeaker of Figure 4.3 varies by ±5 dB in the range 80 Hz–18 kHz, which is easily noticed in direct comparison to the flat response, but without a reference most listeners cannot perceive the deviations when listening to music through the loudspeaker. In a practical listening environment, the interaction of the loudspeaker and the room acoustics makes the situation much more complex. Thus, in listening experiments, eliminating improper room acoustics is important by using loudspeakers in an anechoic chamber or by using headphone reproduction in most critical cases, or by using a specially designed listening room with carefully controlled acoustics. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 504

Categorization

• XREF: Connects to the reader’s noise/silence corpus: room acoustics interacting with loudspeakers echoes the soundscape work on how listening environment shapes perceived signal. — connects to: A decibel value is meaningless without an attached reference level — Almo Farina, Soundscape Ecology: Principles,…, 1943
• SHARE: The ‘±5 dB inaudible without a reference’ fact is perfect cocktail material for an audio engineer or psychologist of perception.
• corroborated: 2 independent passages support this claim — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 504