Background noise. 2.3.1. Measurement criteria for A-weighted sound pressure level
Background noise. 2.3.1. Measurement criteria for A-weighted sound pressure level
2.3.2. Vehicle A-weighted sound pressure level measurement correction criteria
Background noise. During the calibration background noise is also recorded. In a separate measurement the frequency spectrum of the background has been determined and is then subtracted from the calibration signal spectrum. Typically, the background noise is several orders of magnitude below the signal strength. This is even the case for the component |Hθ,vert| with lowest LPDA sensitivity. For large zenith angles close to 90◦ and in the case of the component |Hθ,vert| also for small zenith angles directly above the radio station, however, the background noise and the signal can be of the same order of magnitude. In this case, the calibration signal spectrum constitutes an upper limit of the LPDA |Hφ| [m] 60 ◦ Θ ◦ 45 30 ◦ 15 ◦ ◦ 55 MHz 0 2017 JINST 90 ◦ 7 8 9 10 75 ◦ 60 ◦ Θ 45 ◦ 30 ◦ ◦ 15 ◦ 55 MHz 0 12 90 ◦ |Hθ,hor| [m] ◦ 75 60 ◦ Θ 45 ◦ 30 ◦ 15 ◦ ◦ 55 MHz 0 T10005 90 ◦
Background noise. Noise control measures will be undertaken to achieve a background noise criterion of NC-‐25-‐30 for all of the Lecture Theatre rooms (except booth operator/rack room, which must achieve NC-‐35), in order to provide good speech intelligibility for both local and remote listeners. This includes noise from HVAC and lighting ballasts.
1. Achieving these low NC levels means very tight control of fan noise and air flow conditions.
2. Noise-‐producing HVAC equipment including mixing boxes, fan-‐powered mixing boxes, and fan coil units will be located outside the Lecture Theatre rooms and not within the ceiling plenum space.
Background noise. 2.3.1. Measurement criteria for A-weighted sound pressure level
2.3.2. Vehicle A-weighted sound pressure level measurement correction criteria
Table 1 — 0Correction for level of background noise when measuring vehicle A-weighted sound pressure level Range of maximum to minimum value of the representative background noise A-weighted sound pressure level over a defined time period in dB ∆Lbgn, p-p Sound pressure level of jth test result minus background noise level ∆L = Ltest,j - Lbgn in dB Correction in dB Lcorr - ∆Lbgn > 10 no correction needed 6 ≤ ∆Lbgn ≤8 1,0
Background noise.
1.6.2.1 Achieving low NC levels means very tight control of fan noise and air flow conditions.
1.6.2.2 Noise-producing HVAC equipment including mixing boxes, fan-powered mixing boxes, and fan coil units shall not be located inside VC rooms or within the ceiling plenum space.
Background noise. Noise control measures must be undertaken to achieve a background noise criterion of NC 30-35.
Background noise. Noise control measures will be undertaken to achieve a background noise criterion of NC-‐30-‐35 for Classroom, Learning Space, Computer Lab, and Meeting Room type spaces. This includes noise from HVAC and lighting ballasts.
1. Achieving these low NC levels means very tight control of fan noise and air flow conditions.
2. Noise-‐producing HVAC equipment including mixing boxes, fan-‐powered mixing boxes, and fan coil units will be located outside the Lecture Theatre rooms and not within the ceiling plenum space.
Background noise. 1. In order to provide good speech intelligibility for local and remote listeners:
Background noise
