“I spent a lot of money to buy a soundproof room, but what if I get a complaint from next door…?”
The most anxious thing is, after all, the “actual effect”, isn’t it? Even if you look at the numbers “Dr-35” or “Dr-40” written in the catalog, it’s honest that it’s difficult to imagine specifically how much the sound disappears.
In this article, we will explain the effect of the soundproof room (sound insulation performance) in an easy-to-understand way at the “experience level” instead of numerical values.
What is the soundproof performance index “Dr Grade (D-Value)”?#
The performance of a soundproof room is expressed by the JIS standard “Dr Grade (De-Aru grade)”. Simply put, it is a numerical value of “how much the sound inside can be reduced (can be subtracted)”.
- Dr-30: Subtract “-30dB (decibels)” from the sound
- Dr-40: Subtract “-40dB (decibels)” from the sound
If the original sound is “90dB (piano, etc.)” and the soundproof room is “Dr-40”, the sound leaking outside will be 90dB - 40dB = 50dB.
[Experience Level] How it sounds by Dr Grade#
Now, let’s imagine “how the sound after attenuation actually sounds”. *This is how it sounds in the next room separated by one wall.
Dr-30 to Dr-35 (Standard Level)#
- Effect: A level where “human voices (normal size)” are almost inaudible.
- For instruments: The sound of the piano sounds like “watching TV at a low volume”. You can’t hear the lyrics, but you can tell the tune.
- Applications:
- Telework, web conferences
- Piano practice during the day
- Singing with an acoustic guitar
- Wind instruments such as flute (daytime)
Dr-40 (High Performance Level)#
- Effect: Even “loud voices or shouting” are only slightly audible next door.
- For instruments: The sound of the piano drops to the level of “small voices”. If there is TV or daily life noise, it is a level that does not bother you. Night practice also becomes realistic.
- Applications:
- Night piano practice
- Saxophone, trumpet (brass instruments)
- Full-scale voice recording
- Game streaming (screaming type)
Dr-50 or more (Studio/Commercial Level)#
- Effect: Silence “isolated from the outside world”.
- For instruments: Even if you play a drum set, the next room is about “is something ringing far away?”. It is almost close to silent.
- Applications:
- Playing real drums
- Want to play 24 hours a day
- Building a pro-spec studio
Note: The limit of unit-type soundproof rooms (assembly type) is generally around “Dr-40”. If you aim for Dr-50 or more, “soundproof construction” by a professional contractor is required.
By Application: What performance do you need?#
The way to choose without failure is to choose performance according to the “loudest sound (peak volume)”.
Singing, Game Streaming, Telework
- Recommended: Dr-30 to Dr-35
- For human voices, standard soundproof rooms can cover them sufficiently. However, if your style is “screaming”, Dr-40 is safe.
Upright Piano, Acoustic Guitar, String Instruments
- Recommended: Dr-35 to Dr-40
- Since pianos have large sounds and also vibrations to the floor, Dr-35 or more is essential. If you also play at night, choose Dr-40 without hesitation.
Saxophone, Trumpet, Brass Instruments
- Recommended: Dr-40
- Since the sound is sharp and has penetration power, high sound insulation performance is required. There is a high possibility of dissatisfaction with Dr-30.
Real Drums, Low-frequency Instruments
- Recommended: Dr-50 or more (+ anti-vibration construction)
- Since not only air sound but also “vibration” is tremendous, it cannot be countered with a unit soundproof room alone. It is predicated on expensive renovation construction.
Summary: It’s OK if you lower it to the level of neighbor’s daily life noise#
The goal of soundproofing is not “to zero the sound”. It’s “to make it smaller than the daily life noise of the neighbor’s house (air conditioner, TV, refrigerator, etc.)”.
If you get lost in the environmental sound, people are less likely to recognize sound as “noise”. Choose a Dr grade that suits your application and get a comfortable soundproof life.
→ Related: How a Soundproof Room Works | Why can you eliminate sound? → Back to Soundproof Room Basics Map (Top)