A
- Absorption
- When a material takes in sound energy rather than reflecting it. Soft materials like foam and fabric absorb sound. This reduces echo but doesn't block sound from passing through.
- Acoustic Caulk
- Flexible sealant that remains pliable after drying. Used to seal gaps where sound might leak, especially in areas that might shift slightly over time.
- Acoustic Panel
- Panels designed to absorb sound within a room. They reduce echo and improve sound quality but don't significantly block sound from entering or leaving.
- Airborne Noise
- Sound that travels through the air (voices, music, traffic). Contrast with impact noise, which travels through building structure.
D
- Decibel (dB)
- Unit measuring sound intensity. Normal conversation is about 60 dB, traffic is 70-85 dB, and a rock concert can be 110+ dB. A 10 dB reduction roughly halves perceived loudness.
- Decoupling
- Separating building elements so vibrations can't transfer between them. A wall that's not rigidly connected to the structure transmits less sound.
- Door Sweep
- Hardware that attaches to the bottom of a door to seal the gap between door and floor.
F
- Flanking
- When sound bypasses a barrier by going around it—through gaps, adjacent surfaces, or connected structures. A well-soundproofed wall is useless if sound flanks through the ceiling.
- Frequency
- How "high" or "low" a sound is, measured in Hertz (Hz). Low frequencies (bass) are harder to block than high frequencies.
H
- Hertz (Hz)
- Unit measuring sound frequency. Human hearing ranges from about 20 Hz (very low bass) to 20,000 Hz (very high pitch). Speech is mainly 300-3000 Hz.
I
- IIC (Impact Insulation Class)
- Rating measuring how well a floor/ceiling blocks impact noise like footsteps. Higher numbers are better. Building codes often require IIC 50 minimum between apartments.
- Impact Noise
- Sound created by physical contact with a surface—footsteps, dropped objects, furniture moving. Travels through building structure rather than air.
M
- Mass-Loaded Vinyl (MLV)
- Dense, flexible material used to block sound. Its weight (mass) prevents sound waves from passing through. Can be hung on walls or doors.
- Masking
- Using consistent background sound (like white noise) to make intermittent sounds less noticeable. Doesn't reduce the noise, but makes it less attention-grabbing.
N
- NRC (Noise Reduction Coefficient)
- Rating from 0 to 1 measuring how much sound a material absorbs. Higher means more absorption. An NRC of 0.70 means 70% of sound is absorbed. Relevant for reducing echo, not for blocking sound.
R
- Resilient Channel
- Metal strips that hold drywall slightly away from studs, reducing sound transfer by preventing direct contact. A form of decoupling.
- Reverberation
- Sound bouncing around a room, creating that "echoey" effect. Soft materials and acoustic panels reduce reverberation.
S
- Sound Blocking
- Preventing sound from passing through a barrier. Requires mass and sealed gaps. Different from absorption.
- STC (Sound Transmission Class)
- Rating measuring how well a wall, floor, or other barrier blocks airborne sound. Higher is better. Typical apartment walls are STC 35-45.
T
- Transmission
- Sound passing through a barrier. A wall with high transmission lets more sound through.
W
- Weatherstripping
- Material (foam, rubber, etc.) used to seal gaps around doors and windows. Blocks air and sound from passing through gaps.
- White Noise
- Sound containing all frequencies at equal intensity—sounds like static or hissing. Used for sound masking.
- Window Insert
- Secondary window panel installed inside an existing window frame. The air gap between the insert and window provides sound blocking.