Rw to Rw + Ctr
Type a value in Rw to get it in Rw+Ctr instantly.
45Rw+Ctr
That's 3.2× as quiet as a blockwork wall, while a party wall is 2× better. A 75 dB television next door would come through at about 25 dB.
What it means
How much sound gets through?
STC and Rw use different weighting curves, so the one-decibel offset is a good rule of thumb, not an exact conversion. Both ignore low bass, where walls perform worst.
The math
How to convert Rw to Rw+Ctr
The rating is a logarithm of what gets through: dB = −10 × log₁₀(transmitted fraction). STC runs about one decibel above Rw for ordinary partitions.
Example: 50 Rw = 45 Rw+Ctr.
Every unit
Your rating in every unit
Tables
Rw to Rw+Ctr conversion table
| Rw | Rw+Ctr |
|---|---|
| 20 Rw | 15 Rw+Ctr |
| 25 Rw | 20 Rw+Ctr |
| 30 Rw | 25 Rw+Ctr |
| 35 Rw | 30 Rw+Ctr |
| 40 Rw | 35 Rw+Ctr |
| 45 Rw | 40 Rw+Ctr |
| 50 Rw | 45 Rw+Ctr |
| 55 Rw | 50 Rw+Ctr |
| 60 Rw | 55 Rw+Ctr |
| 65 Rw | 60 Rw+Ctr |
| 70 Rw | 65 Rw+Ctr |
Rw+Ctr to Rw conversion table
| Rw+Ctr | Rw |
|---|---|
| 20 Rw+Ctr | 25 Rw |
| 25 Rw+Ctr | 30 Rw |
| 30 Rw+Ctr | 35 Rw |
| 35 Rw+Ctr | 40 Rw |
| 40 Rw+Ctr | 45 Rw |
| 45 Rw+Ctr | 50 Rw |
| 50 Rw+Ctr | 55 Rw |
| 55 Rw+Ctr | 60 Rw |
| 60 Rw+Ctr | 65 Rw |
| 65 Rw+Ctr | 70 Rw |
| 70 Rw+Ctr | 75 Rw |
Quick answers
Quick answers
- How many Rw+Ctr is 1 Rw?
- 1 Rw is -4 Rw+Ctr.
- How many Rw+Ctr is 10 Rw?
- 10 Rw is 5 Rw+Ctr.
- How many Rw+Ctr is 50 Rw?
- 50 Rw is 45 Rw+Ctr.
The units
About these units
Rw (Rw)
The international weighted sound reduction index, in decibels.
Rw + Ctr (Rw+Ctr)
Rw with a traffic-noise correction, typically 5 dB lower.
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