CCAUV.AK1, EUROMET.AUV.AK1, APMP.AUV.AK1, SIM.AUV.AK1, APMP.AUV.AK1.1, COOMET.AUV.AK1, and COOMET.AUV.AK1.1
MEASURAND : Pressure sensitivity level of LS1P laboratory standard microphones
NOMINAL VALUE : 0 dB
FREQUENCY : 250 Hz
Degrees of equivalence D_{i} and expanded uncertainty U_{i} (k = 2) expressed in dB
The horizontal continuous line crosses the yaxis at the value 0 dB
Click on the graph for a closer view
Red diamonds : CCAUV.AK1 participants
Green triangles : EUROMET.AUV.AK1 participants only
Blue squares : APMP.AUV.AK1 participants only
Black circles : SIM.AUV.AK1 participants only
Orange square : APMP.AUV.AK1.1 participant only
Pink circles : COOMET.AUV.AK1 participants only
Grey triangle : COOMET.AUV.AK1.1 participant only
CCAUV.AK1, EUROMET.AUV.AK1, APMP.AUV.AK1, SIM.AUV.AK1, APMP.AUV.AK1.1, COOMET.AUV.AK1, and COOMET.AUV.AK1.1
MEASURAND : Pressure sensitivity level of LS1P laboratory standard microphones
NOMINAL VALUE : 0 dB
FREQUENCY : 1000 Hz
Degrees of equivalence D_{i} and expanded uncertainty U_{i} (k = 2) expressed in dB
The horizontal continuous line crosses the yaxis at the value 0 dB
Click on the graph for a closer view
Red diamonds : CCAUV.AK1 participants
Green triangles : EUROMET.AUV.AK1 participants only
Blue squares : APMP.AUV.AK1 participants only
Black circles : SIM.AUV.AK1 participants only
Orange square : APMP.AUV.AK1.1 participant only
Pink circles : COOMET.AUV.AK1 participants only
Grey triangle : COOMET.AUV.AK1.1 participant only
CCAUV.AK1, EUROMET.AUV.AK1, APMP.AUV.AK1, SIM.AUV.AK1, APMP.AUV.AK1.1, COOMET.AUV.AK1, and COOMET.AUV.AK1.1
MEASURAND : Pressure sensitivity level of LS1P laboratory standard microphones
NOMINAL VALUE : 0 dB
FREQUENCY : 63 Hz to 8 kHz
Graphs of equivalence are only provided for frequencies 250 Hz and 1000 Hz.
Degrees of equivalence D_{i} and expanded uncertainty U_{i} (k = 2) expressed in dB
The horizontal continuous lines cross the yaxis at the value 0 dB
Click on the graph for a closer view
Red diamonds : CCAUV.AK1 participants
Green triangles : EUROMET.AUV.AK1 participants only
Blue squares : APMP.AUV.AK1 participants only
Black circles : SIM.AUV.AK1 participants only
Orange square : APMP.AUV.AK1.1 participant only
Pink circles : COOMET.AUV.AK1 participants only
Grey triangle : COOMET.AUV.AK1.1 participant only
CCAUV.AK1, EUROMET.AUV.AK1, APMP.AUV.AK1, SIM.AUV.AK1, APMP.AUV.AK1.1, COOMET.AUV.AK1, and COOMET.AUV.AK1.1
MEASURAND : Pressure sensitivity level of LS1P laboratory standard microphones
NOMINAL VALUE : 0 dB
FREQUENCY : 250 Hz
Degrees of equivalence relative to the CCAUV.AK1 key comparison reference value, expressed in dB
In dark blue : CCAUV.AK1 participants
In green : EUROMET.AUV.AK1 participants only
In blue : APMP.AUV.AK1 participants only
In black : SIM.AUV.AK1 participants only
In orange : APMP.AUV.AK1.1 participant only
In pink : COOMET.AUV.AK1 participants only
In grey : COOMET.AUV.AK1.1 participant only
The pairwise degrees of equivalence are given in the yellow part of the matrix presented below. All values are expressed in dB.
NPL  0.01  0.03 
CENAM  0.00  0.04 
CSIRNML  0.02  0.05 
NMIA  0.02  0.04 
DPLA  0.00  0.03 
NMIJ  0.01  0.04 
GUM  0.01  0.03 
KRISS  0.00  0.03 
NIST  0.01  0.04 
NRC  0.04  0.03 
PTB  0.01  0.03 
VNIIFTRI  0.00  0.05 
BEV*  0.01  0.03 
SP*  0.01  0.04 
IEN*  0.01  0.05 
UME*  0.02  0.05 
METAS*  0.01  0.03 
SMU*  0.00  0.04 
OMH*  0.03  0.07 
CMI*  0.04  0.03 
NMIA**  0.00  0.04 
CMS/ITRI**  0.01  0.04 
NIM**  0.01  0.05 
NIMT**  0.00  0.04 
NMLSIRIM**  0.00  0.03 
NPLI**  0.02  0.07 
SCL**  0.01  0.04 
INMETRO***  0.04  0.05 
INTI***  0.02  0.05 
KIMLIPI****  0.01  0.08 
UME^  0.02  0.06 
SMU^  0.01  0.05 
DNDI^^  0.02  0.06 
* EUROMET.AUV.AK1 participants only
** APMP.AUV.AK1 participants only
*** SIM.AUV.AK1 participants only
**** APMP.AUV.AK1.1 participant only
^ COOMET.AUV.AK1 participants only
^^ COOMET.AUV.AK1.1 participant only
Results are presented under A4 printable format in Summary Results (.PDF file).
Data obtained at 250 Hz is characteristic of frequencies up to 2 kHz.
CCAUV.AK1, EUROMET.AUV.AK1, APMP.AUV.AK1, SIM.AUV.AK1, APMP.AUV.AK1.1, COOMET.AUV.AK1, and COOMET.AUV.AK1.1
MEASURAND : Pressure sensitivity level of LS1P laboratory standard microphones
NOMINAL VALUE : 0 dB
FREQUENCY : 1000 Hz
Degrees of equivalence relative to the CCAUV.AK1 key comparison reference values, expressed in dB
In dark blue : CCAUV.AK1 participants
In green : EUROMET.AUV.AK1 participants only
In blue : APMP.AUV.AK1 participants only
In black : SIM.AUV.AK1 participants only
In orange : APMP.AUV.AK1.1 participant only
In pink : COOMET.AUV.AK1 participants only
In grey : COOMET.AUV.AK1.1 participants only
Results are presented under A4 printable format in Summary Results (.PDF file).
The pairwise degrees of equivalence are computed only for frequency 250 Hz. This data is characteristic of frequencies up to 2 kHz.
CCAUV.AK1, EUROMET.AUV.AK1, APMP.AUV.AK1, SIM.AUV.AK1, APMP.AUV.AK1.1, COOMET.AUV.AK1, and COOMET.AUV.AK1.1
MEASURAND : Pressure sensitivity level of LS1P laboratory standard microphones
NOMINAL VALUE : 0 dB
FREQUENCY : 63 Hz to 8 kHz
Degrees of equivalence D_{i} and expanded uncertainty U_{i} (k = 2) expressed in dB
In dark blue : CCAUV.AK1 participants
In green : EUROMET.AUV.AK1 participants only
In blue : APMP.AUV.AK1 participants only
In black : SIM.AUV.AK1 participants only
In orange : APMP.AUV.AK1.1 participant only
In pink : COOMET.AUV.AK1 participants only
In grey : COOMET.AUV.AK1.1 participant only
Results are presented under A4 printable format in Summary Results (.PDF file).
The pairwise degrees of equivalence are computed only for frequency 250 Hz. This data is characteristic of frequencies up to 2 kHz.
Metrology area, Subfield  Acoustics, Ultrasound, Vibration, Acoustics 
Description  Comparison of laboratory standard microphone calibrations 
Time of measurements  2002  2003 
Status  Approved for equivalence 
Final Reports of the comparisons  
Measurand  Sound pressure 
Parameters  Frequency: 63 Hz to 10 kHz 
Transfer device  Two LS1P standard laboratory microphones 
Comparison type  Key Comparison 
Consultative Committee  CCAUV (Consultative Committee for Acoustics, Ultrasound and Vibration) 
Conducted by  COOMET (EuroAsian Cooperation of National Metrological Institutions) 
RMO Internal Identifier  COOMET 226/DE/01 
Comments  A subsequent bilateral key comparison, COOMET.AUV.AK1.1, was organized in 2004 between PTB and DNDI "Systema". The results of DNDI "Systema" obtained in key comparison COOMET.AUV.AK1 are not reported here. Results published on 02 July 2009 COOMET.AUV.AK1 results are linked to those of CCAUV.AK1 Pressure sensitivity level of laboratory standard microphones LS1P 
Pilot institute 
PTB
PhysikalischTechnische Bundesanstalt Germany 
Contact person  T. Fedtke thomas.fedtke@ptb.de +49 (0) 531 592 1511 
Pilot laboratory  

PTB 
PhysikalischTechnische Bundesanstalt, Germany, EURAMET 
GUM 
Glowny Urzad Miar, Central Office of Measures, Poland, EURAMET 
SE "NDI Systema" 
State Enterprise "ScientificResearch Institute for Metrology of Measurement and Control Systems", Ukraine, COOMET 
SMU 
Slovensky Metrologicky Ustav, Slovakia, EURAMET 
UME 
TÜBITAK Ulusal Metroloji Enstitüsü, Turkey, EURAMET 
VNIIFTRI 
Institute of Physical Technical and Radiotechnical Measurements, Rosstandart, Russian Federation, COOMET 
This page proposes printout on A4 paper (portrait) of the comparison details (best printed out using a black and white printer).
Please, select items to be printed out, then click on "OK" :
CCAUV.AK1, EUROMET.AUV.AK1, APMP.AUV.AK1, SIM.AUV.AK1, APMP.AUV.AK1.1, COOMET.AUV.AK1, and COOMET.AUV.AK1.1
MEASURAND : Pressure sensitivity level of LS1P laboratory standard microphones
NOMINAL VALUE : 0 dB
FREQUENCY : 250 Hz
The key comparison reference value, x_{R} (designated as M_{ref} in the CCAUV.AK1 Final Report), is obtained as the arithmetic mean of all measurements, normalized to zero decibels. The combined standard uncertainty, u_{R} (designated as u_{ref} in the same Final Report), of the key comparison reference value is determined by propagating the individual measurement uncertainties. At frequency 250 Hz, x_{R} = 0.00 dB and u_{R} = 0.005 dB. 
The degree of equivalence of laboratory i with respect to the key comparison reference value is given by a pair of terms: D_{i} = (x_{i}  x_{R}) and U_{i}, its expanded uncertainty (k = 2), both expressed in dB. U_{i} = 2[(1  2/n)u_{i}^{2} + u_{R}^{2}]^{1/2}, where n is the number of participants. 
The degree of equivalence between two laboratories i and j is given by a pair of terms: D_{ij} = D_{i}  D_{j} = (x_{i}  x_{j}) and U_{ij}, its expanded uncertainty (k = 2), both expressed in dB. U_{ij} = 2(u_{i}^{2} + u_{j}^{2})^{1/2}. 
NPL, DPLA and PTB provide the link between key comparisons CCAUV.AK1 and EUROMET.AUV.AK1.
The process involves calculating the average result of the linking participants in each comparison. The difference between the average result relative to the CCAUV.AK1 key comparison reference value and relative to the EUROMET.AUV.AK1 internal reference provides a linking factor, d_{EUR}, which is used to convert the results relative to the EUROMET internal reference, so they become relative to the CCAUV.AK1 key comparison reference value.
At frequency 250 Hz, d_{EUR} = 0.001 dB 
The degree of equivalence of laboratory i participant in EUROMET.AUV.AK1 with respect to the key comparison reference value is given by a pair of terms: D_{i} = (x_{iEUR} + d_{EUR}) and U_{i}, its expanded uncertainty (k = 2), both expressed in dB. U_{i} = 2(u_{iEUR}^{2} + u_{R}^{2})^{1/2}. 
The degree of equivalence between two laboratories i and j is given by a pair of terms: D_{ij} = (x_{i}  x_{j}) and U_{ij}, its expanded uncertainty (k = 2), both expressed in dB. U_{ij} = 2(u_{i}^{2} + u_{j}^{2})^{1/2}. The index i (or j) should be taken as iEUR (or jEUR) when the corresponding laboratory has participated in EUROMET.AUV.AK1 only. 
NMIJ and KRISS provide the link between key comparisons CCAUV.AK1 and APMP.AUV.AK1. NMIA also took part in both key comparisons, but was not included as a linking laboratory because it used different equipments.
The process involves calculating the average result of the linking participants in each comparison. The difference between the average result relative to the CCAUV.AK1 key comparison reference value and relative to the APMP.AUV.AK1 internal reference provides a linking factor, d_{APMP}, which is used to convert the results relative to the APMP internal reference, so they become relative to the CCAUV.AK1 key comparison reference value.
At frequency 250 Hz, d_{APMP} = 0.005 dB 
The degree of equivalence of laboratory i participant in APMP.AUV.AK1 with respect to the key comparison reference value is given by a pair of terms: 
The degree of equivalence between two laboratories i and j is given by a pair of terms: D_{ij} = (x_{i}  x_{j}) and U_{ij}, its expanded uncertainty (k = 2), both expressed in dB. U_{ij} = 2(u_{i}^{2} + u_{j}^{2})^{1/2}. The index i and j should be taken as iAPMP and jAPMP when both laboratories have participated in APMP.AUV.AK1 only. 
NRC, NIST and CENAM provide the link between key comparisons CCAUV.AK1 and SIM.AUV.AK1, which is computed using a generalized linear leastsquares method, as explained in Annex B on page 19 of the SIM.AUV.AK1 Final Report.
The degree of equivalence of laboratory i participant in SIM.AUV.AK1 only, with respect to the CCAUV.AK1 key comparison reference value, is given by a pair of terms: D_{i} and its expanded uncertainty (k = 2), U_{i}, both expressed in dB. These are computed as explained in Annex B of the SIM.AUV.AK1 Final Report. 
The degree of equivalence between two laboratories i and j is given by a pair of terms: D_{ij} and its expanded uncertainty (k = 2), U_{ij}, both expressed in dB. These are computed as explained in Annex B of the SIM.AUV.AK1 Final Report. 
KRISS provides the link between key comparisons CCAUV.AK1 and APMP.AUV.AK1.1. The linking process is explained in section 8 of the APMP.AUV.AK1.1 Final Report.
The degree of equivalence of KIMLIPI participant in APMP.AUV.AK1.1 only, with respect to the CCAUV.AK1 key comparison reference value, is given by a pair of terms: D_{i} and its expanded uncertainty (k = 2), U_{i}, both expressed in dB. These are computed as explained in section 8 of the APMP.AUV.AK1.1 Final Report. 
No pairwise degrees of equivalence are computed between KIMLIPI and participants in CCAUV.AK1 and other linked key comparisons. 
GUM, PTB and VNIIFTRI provide the link between key comparisons CCAUV.AK1 and COOMET.AUV.AK1. The linking process is explained in section 6 of the COOMET.AUV.AK1 Final Report.
The degree of equivalence of laboratory i participant in COOMET.AUV.AK1 only, with respect to the CCAUV.AK1 key comparison reference value, is given by a pair of terms: D_{i} and its expanded uncertainty (k = 2), U_{i}, both expressed in dB. These are computed as explained in section 6 of COOMET.AUV.AK1 Final Report. 
The degree of equivalence between two laboratories i and j is given by a pair of terms: D_{ij} and its expanded uncertainty (k = 2), U_{ij}, both expressed in dB. These are computed as explained in section 6 of COOMET.AUV.AK1 Final Report. 
PTB provides the link between key comparisons CCAUV.AK1 and COOMET.AUV.AK1.1. The linking process is explained in section 6 of the COOMET.AUV.AK1.1 Final Report.
The degree of equivalence of DNDI participant in COOMET.AUV.AK1.1 only, with respect to the CCAUV.AK1 key comparison reference value, is given by a pair of terms: D_{i} and its expanded uncertainty (k = 2), U_{i}, both expressed in dB. These are computed as explained in section 6 of COOMET.AUV.AK1.1 Final Report. 
No pairwise degrees of equivalence involving DNDI are given here. 
CCAUV.AK1, EUROMET.AUV.AK1, APMP.AUV.AK1, SIM.AUV.AK1, APMP.AUV.AK1.1, COOMET.AUV.AK1, and COOMET.AUV.AK1.1
MEASURAND : Pressure sensitivity level of LS1P laboratory standard microphones
NOMINAL VALUE : 0 dB
FREQUENCY : 1000 Hz
The key comparison reference value, x_{R} (designated as M_{ref} in the CCAUV.AK1 Final Report), is obtained as the arithmetic mean of all measurements, normalized to zero decibels. The combined standard uncertainty, u_{R} (designated as u_{ref} in the same Final Report), of the key comparison reference value is determined by propagating the individual measurement uncertainties. At frequency 1000 Hz, x_{R} = 0.00 dB and u_{R} = 0.005 dB. 
The degree of equivalence of laboratory i with respect to the key comparison reference value is given by a pair of terms: D_{i} = (x_{i}  x_{R}) and U_{i}, its expanded uncertainty (k = 2), both expressed in dB. U_{i} = 2[(1  2/n)u_{i}^{2} + u_{R}^{2}]^{1/2}, where n is the number of participants. 
The degree of equivalence between two laboratories i and j is given by a pair of terms: D_{ij} = D_{i}  D_{j} = (x_{i}  x_{j}) and U_{ij}, its expanded uncertainty (k = 2), both expressed in dB. U_{ij} = 2(u_{i}^{2} + u_{j}^{2})^{1/2}. 
NPL, DPLA and PTB provide the link between key comparisons CCAUV.AK1 and EUROMET.AUV.AK1.
The process involves calculating the average result of the linking participants in each comparison. The difference between the average result relative to the CCAUV.AK1 key comparison reference value and relative to the EUROMET.AUV.AK1 internal reference provides a linking factor, d_{EUR}, which is used to convert the results relative to the EUROMET internal reference, so they become relative to the CCAUV.AK1 key comparison reference value.
At frequency 1000 Hz, d_{EUR} = 0.007 dB 
The degree of equivalence of laboratory i participant in EUROMET.AUV.AK1 with respect to the key comparison reference value is given by a pair of terms: D_{i} = (x_{iEUR} + d_{EUR}) and U_{i}, its expanded uncertainty (k = 2), both expressed in dB. U_{i} = 2(u_{iEUR}^{2} + u_{R}^{2})^{1/2}. 
The degree of equivalence between two laboratories i and j is given by a pair of terms: D_{ij} = (x_{i}  x_{j}) and U_{ij}, its expanded uncertainty (k = 2), both expressed in dB. U_{ij} = 2(u_{i}^{2} + u_{j}^{2})^{1/2}. The index i (or j) should be taken as iEUR (or jEUR) when the corresponding laboratory has participated in EUROMET.AUV.AK1 only. 
NMIJ and KRISS provide the link between key comparisons CCAUV.AK1 and APMP.AUV.AK1. NMIA also took part in both key comparisons, but was not included as a linking laboratory because it used different equipments.
The process involves calculating the average result of the linking participants in each comparison. The difference between the average result relative to the CCAUV.AK1 key comparison reference value and relative to the APMP.AUV.AK1 internal reference provides a linking factor, d_{APMP}, which is used to convert the results relative to the APMP internal reference, so they become relative to the CCAUV.AK1 key comparison reference value.
At frequency 1000 Hz, d_{APMP} = 0.002 dB 
The degree of equivalence of laboratory i participant in APMP.AUV.AK1 with respect to the key comparison reference value is given by a pair of terms: 
The degree of equivalence between two laboratories i and j is given by a pair of terms: D_{ij} = (x_{i}  x_{j}) and U_{ij}, its expanded uncertainty (k = 2), both expressed in dB. U_{ij} = 2(u_{i}^{2} + u_{j}^{2})^{1/2}. The index i and j should be taken as iAPMP and jAPMP when both laboratories have participated in APMP.AUV.AK1 only. 
NRC, NIST and CENAM provide the link between key comparisons CCAUV.AK1 and SIM.AUV.AK1, which is computed using a generalized linear leastsquares method, as explained in Annex B on page 19 of the SIM.AUV.AK1 Final Report.
The degree of equivalence of laboratory i participant in SIM.AUV.AK1 only, with respect to the CCAUV.AK1 key comparison reference value, is given by a pair of terms: D_{i} and its expanded uncertainty (k = 2), U_{i}, both expressed in dB. These are computed as explained in Annex B of the SIM.AUV.AK1 Final Report. 
The degree of equivalence between two laboratories i and j is given by a pair of terms: D_{ij} and its expanded uncertainty (k = 2), U_{ij}, both expressed in dB. These are computed as explained in Annex B of the SIM.AUV.AK1 Final Report. 
KRISS provides the link between key comparisons CCAUV.AK1 and APMP.AUV.AK1.1. The linking process is explained in section 8 of the APMP.AUV.AK1.1 Final Report.
The degree of equivalence of KIMLIPI participant in APMP.AUV.AK1.1 only, with respect to the CCAUV.AK1 key comparison reference value, is given by a pair of terms: D_{i} and its expanded uncertainty (k = 2), U_{i}, both expressed in dB. These are computed as explained in section 8 of the APMP.AUV.AK1.1 Final Report. 
No pairwise degrees of equivalence are computed between KIMLIPI and participants in CCAUV.AK1 and other linked key comparisons. 
GUM, PTB and VNIIFTRI provide the link between key comparisons CCAUV.AK1 and COOMET.AUV.AK1. The linking process is explained in section 6 of the COOMET.AUV.AK1 Final Report.
The degree of equivalence of laboratory i participant in COOMET.AUV.AK1 only, with respect to the CCAUV.AK1 key comparison reference value, is given by a pair of terms: D_{i} and its expanded uncertainty (k = 2), U_{i}, both expressed in dB. These are computed as explained in section 6 of COOMET.AUV.AK1 Final Report. 
The degree of equivalence between two laboratories i and j is given by a pair of terms: D_{ij} and its expanded uncertainty (k = 2), U_{ij}, both expressed in dB. These are computed as explained in section 6 of COOMET.AUV.AK1 Final Report. 
PTB provides the link between key comparisons CCAUV.AK1 and COOMET.AUV.AK1.1. The linking process is explained in section 6 of the COOMET.AUV.AK1.1 Final Report.
The degree of equivalence of DNDI participant in COOMET.AUV.AK1.1 only, with respect to the CCAUV.AK1 key comparison reference value, is given by a pair of terms: D_{i} and its expanded uncertainty (k = 2), U_{i}, both expressed in dB. These are computed as explained in section 6 of COOMET.AUV.AK1.1 Final Report. 
No pairwise degrees of equivalence involving DNDI are given here. 
CCAUV.AK1, EUROMET.AUV.AK1, APMP.AUV.AK1, SIM.AUV.AK1, APMP.AUV.AK1.1, COOMET.AUV.AK1, and COOMET.AUV.AK1.1
MEASURAND : Pressure sensitivity level of LS1P laboratory standard microphones
NOMINAL VALUE : 0 dB
FREQUENCY : 63 Hz to 8 kHz
The key comparison reference values, x_{R} (designated as M_{ref} in the CCAUV.AK1 Final Report), are obtained as the arithmetic means of all measurements, normalized to zero decibels, at each frequency. At a given frequency, the combined standard uncertainty, u_{R} (designated as u_{ref} in the same Final Report), of the key comparison reference value is determined by propagating the individual measurement uncertainties.

At a given frequency, the degree of equivalence of laboratory i with respect to the reference value is given by a pair of terms: D_{i} = (x_{i}  x_{R}) and U_{i}, its expanded uncertainty (k = 2), both expressed in dB. U_{i} = 2[(1  2/n)u_{i}^{2} + u_{R}^{2}]^{1/2}, where n is the number of participants. 
At a given frequency, the degree of equivalence between two laboratories i and j is given by a pair of terms: 
NPL, DPLA and PTB provide the link between key comparisons CCAUV.AK1 and EUROMET.AUV.AK1.
The process involves calculating the average result of the linking participants at each frequency, in each comparison. The difference between the average result relative to the CCAUV.AK1 key comparison reference value and relative to the EUROMET.AUV.AK1 internal reference provides a linking factor, d, which is used to convert the results relative to the EUROMET internal reference, so they become relative to the CCAUV.AK1 key comparison reference value.

At a given frequency, the degree of equivalence of laboratory i participant in EUROMET.AUV.AK1 with respect to the key comparison reference value is given by a pair of terms: D_{i} = (x_{iEUR} + d) and U_{i}, its expanded uncertainty (k = 2), both expressed in dB. U_{i} = 2(u_{iEUR}^{2} + u_{R}^{2})^{1/2}. Full graphs of equivalence are given for frequencies 250 Hz and 1000 Hz. 
At a given frequency, the degree of equivalence between two laboratories i and j is given by a pair of terms: D_{ij} = (x_{i}  x_{j}) and U_{ij}, its expanded uncertainty (k = 2), both expressed in dB. U_{ij} = 2(u_{i}^{2} + u_{j}^{2})^{1/2}. The index i (or j) should be taken as 
NMIJ and KRISS provide the link between key comparisons CCAUV.AK1 and APMP.AUV.AK1. NMIA also took part in both key comparisons, but was not included as a linking laboratory because it used different equipments.
The process involves calculating the average result of the linking participants at each frequency, in each comparison. The difference between the average result relative to the CCAUV.AK1 key comparison reference value and relative to the APMP.AUV.AK1 internal reference provides a linking factor, d, which is used to convert the results relative to the APMP internal reference, so they become relative to the CCAUV.AK1 key comparison reference value.

At a given frequency, the degree of equivalence of laboratory i participant in APMP.AUV.AK1 with respect to the key comparison reference value is given by a pair of terms: D_{i} = (x_{iAPMP} + d) and U_{i}, its expanded uncertainty (k = 2), both expressed in dB. U_{i} ~ 2(u_{iAPMP}^{2} + u_{R}^{2})^{1/2}. The exact formula used to compute U_{i} is given in equation 12 on page 22 of the APMP.AUV.AK1 Final Report. Full graphs of equivalence are given for frequencies 250 Hz and 1000 Hz. 
At a given frequency, the degree of equivalence between two laboratories i and j is given by a pair of terms: D_{ij} = (x_{i}  x_{j}) and U_{ij}, its expanded uncertainty (k = 2), both expressed in dB. U_{ij} = 2(u_{i}^{2} + u_{j}^{2})^{1/2}. The index i and j should be taken as iAPMP and jAPMP when both laboratories have participated in APMP.AUV.AK1 only. 
NRC, NIST and CENAM provide the link between key comparisons CCAUV.AK1 and SIM.AUV.AK1, which is computed using a generalized linear leastsquares method, as explained in Annex B on page 19 of the SIM.AUV.AK1 Final Report.
At a given frequency, the degree of equivalence of one laboratory participant in SIM.AUV.AK1 only, with respect to the CCAUV.AK1 key comparison reference value, is given by a pair of terms: D_{i} and its expanded uncertainty (k = 2), U_{i}, both expressed in dB. These are computed as explained in Annex B of the SIM.AUV.AK1 Final Report. Full graphs of equivalence are given for frequencies 250 Hz and 1000 Hz. 
At a given frequency, the degree of equivalence between two laboratories i and j is given by a pair of terms: D_{ij}, and its expanded uncertainty (k = 2), U_{ij}, both expressed in dB. These are computed as explained in Annex B of the SIM.AUV.AK1 Final Report. 
KRISS provides the link between key comparisons CCAUV.AK1 and APMP.AUV.AK1.1. The linking process is explained in section 8 of the APMP.AUV.AK1.1 Final Report.
The degree of equivalence of KIMLIPI participant in APMP.AUV.AK1.1 only, with respect to the CCAUV.AK1 key comparison reference value, is given by a pair of terms: D_{i} and its expanded uncertainty (k = 2), U_{i}, both expressed in dB. These are computed as explained in section 8 of the APMP.AUV.AK1.1 Final Report. 
No pairwise degrees of equivalence are computed between KIMLIPI and participants in CCAUV.AK1 and other linked key comparisons. 
GUM, PTB and VNIIFTRI provide the link between key comparisons CCAUV.AK1 and COOMET.AUV.AK1. The linking process is explained in section 6 of the COOMET.AUV.AK1 Final Report.
The degree of equivalence of laboratory i participant in COOMET.AUV.AK1 only, with respect to the CCAUV.AK1 key comparison reference value, is given by a pair of terms: D_{i} and its expanded uncertainty (k = 2), U_{i}, both expressed in dB. These are computed as explained in section 6 of COOMET.AUV.AK1 Final Report. 
The degree of equivalence between two laboratories i and j is given by a pair of terms: D_{ij} and its expanded uncertainty (k = 2), U_{ij}, both expressed in dB. These are computed as explained in section 6 of COOMET.AUV.AK1 Final Report. 
PTB provides the link between key comparisons CCAUV.AK1 and COOMET.AUV.AK1.1. The linking process is explained in section 6 of the COOMET.AUV.AK1.1 Final Report.
The degree of equivalence of DNDI participant in COOMET.AUV.AK1.1 only, with respect to the CCAUV.AK1 key comparison reference value, is given by a pair of terms: D_{i} and its expanded uncertainty (k = 2), U_{i}, both expressed in dB. These are computed as explained in section 6 of COOMET.AUV.AK1.1 Final Report. 
No pairwise degrees of equivalence involving DNDI are given here. 
CCAUV.AK1, EUROMET.AUV.AK1, APMP.AUV.AK1, SIM.AUV.AK1, APMP.AUV.AK1.1, COOMET.AUV.AK1, and COOMET.AUV.AK1.1
MEASURAND : Pressure sensitivity level of LS1P laboratory standard microphones
NOMINAL VALUE : 0 dB
FREQUENCY : 250 Hz
x_{i} : result of measurements carried out by laboratory i (designated as M_{i} in the CCAUV.AK1 Final Report)
The quoted pressure sensitivity levels are the mean of measurements on two microphones, relative to the arithmetic mean value of all such measurement made in this key comparison.
The nominal value is therefore 0 dB, the key comparison reference value (see the equivalence statements).
u_{i} : combined standard uncertainty of x_{i}
The uncertainty quoted in the following table is 2u_{i}, so that it can be given at a resolution consistent with the measured data.
Lab i
x_{i}
/ dB2u_{i }/ dB
NPL
0.01
0.03
CENAM
0.00
0.04
CSIRNML
0.02
0.05
NMIA
0.02
0.04
DPLA
0.00
0.03
NMIJ
0.01
0.04
GUM
0.01
0.03
KRISS
0.00
0.03
NIST
0.01
0.04
NRC
0.04
0.03
PTB
0.01
0.03
VNIIFTRI
0.00
0.05
x_{iEUR} : result of measurements carried out by laboratory i (designated as M_{i} in the EUROMET.AUV.AK1 Final Report)
The quoted pressure sensitivity levels are relative to internal EUROMET reference values, computed as explained on page 3 of the EUROMET.AUV.AK1 Final Report for each frequency, so the nominal value is 0 dB by design.
u_{iEUR} : combined standard uncertainty of x_{iEUR}
The uncertainty quoted in the following table is 2u_{iEUR}, so that it can be given at a resolution consistent with the measured data.
Lab i
x_{iEUR}
/ dB2u_{iEUR }/ dB
NPL
0.00
0.03
DPLA
0.01
0.03
BEV
0.01
0.03
SP
0.01
0.04
IEN
0.01
0.05
PTB
0.02
0.03
UME
0.03
0.05
METAS
0.01
0.03
SMU
0.01
0.04
OMH
0.04
0.07
CMI
0.04
0.03
x_{iAPMP} : result of measurements carried out by laboratory i
The quoted pressure sensitivity levels are relative to internal APMP reference values, computed as explained on page 16 of the APMP.AUV.AK1 Final Report for each frequency, so the nominal value is 0 dB by design.
u_{iAPMP} : combined standard uncertainty of x_{iAPMP}
The uncertainty quoted in the following table is 2u_{iAPMP}, so that it can be given at a resolution consistent with the measured data.
Lab i
x_{iAPMP}
/ dB2u_{iAPMP }/ dB
CMS/ITRI
0.02
0.04
KRISS
0.00
0.03
NIM
0.01
0.05
NIMT
0.00
0.04
NMIA
0.00
0.04
NMLSIRIM
0.00
0.03
NPLI
0.01
0.07
SCL
0.00
0.04
NMIJ
0.00
0.04
x_{iSIM} : result of measurements carried out by laboratory i
The quoted pressure sensitivity levels are relative to internal SIM reference values, obtained as the arithmetic mean of all measurements available for each microphone, see on page 12 of the SIM.AUV.AK1 Final Report, so the nominal value is 0 dB by design.
u_{iSIM} : combined standard uncertainty of x_{iSIM}
The transfer standards were calibrated by the pilot laboratory, NRC, before delivery and after return from a participating laboratory.
Microphone serial number 907045
Lab i
x_{iSIM}
/ dBu_{iSIM }/ dB
NRC
0.01
0.01
NIST
0.01
0.02
NRC
0.02
0.01
CENAM
0.03
0.02
NRC
0.01
0.01
INMETRO
0.04
0.025
NRC
0.00
0.01
INTI
0.02
0.025
NRC
0.00
0.01
Microphone serial number 1734004
Lab i
x_{iSIM}
/ dBu_{iSIM }/ dB
NRC
0.00
0.01
NIST
0.00
0.02
NRC
0.01
0.01
CENAM
0.01
0.02
NRC
0.00
0.01
INMETRO
0.02
0.025
NRC
0.00
0.01
INTI
0.01
0.025
NRC
0.00
0.01
x_{KIMLIPI(APMPK1.1)}: result of measurements carried out by KIMLIPI obtained as the difference between KRISS and KIMLIPI as explained in section 8 of the APMP.AUV.AK1.1 Final Report.
U_{KIMLIPI(APMPK1.1)} : expanded uncertainty of x_{KIMLIPI(APMPK1.1)}
x_{KIMLIPI(APMPK1.1)} = 0.01 dB
U_{KIMLIPI(APMPK1.1)} = 0.08 dB
x_{iCOO} : result of measurements carried out by laboratory i participant in COOMET.AUV.AK1
u_{iCOO} : combined standard uncertainty of x_{iCOO}
Microphone 4160.2302519
Lab i
x_{iCOO}
/ dB2u_{iCOO }/ dB
PTB
26.93
0.03
GUM
26.95
0.03
UME
26.94
0.06
SMU
26.95
0.04
VNIIFTRI
26.98
0.04
Microphone 4160.2302521
PTB
26.92
0.03
GUM
26.94
0.03
UME
26.93
0.06
SMU
26.94
0.04
VNIIFTRI
26.96
0.04
Lab i
x_{ i}_{COO }/ dB
2u_{i}_{COO }/ dB
x_{i}_{COO.1} : result of measurements carried out by laboratory i participant in COOMET.AUV.AK1.1
u_{iCOO.1} : combined standard uncertainty of x_{i}_{COO.1}
Microphone 4160.2302520
PTB
26.95
0.03
DNDI
26.95
0.05
Lab i
x_{ i}_{COO.1}
/ dB2u_{i}_{COO.1}
/ dB
CCAUV.AK1, EUROMET.AUV.AK1, APMP.AUV.AK1, SIM.AUV.AK1, APMP.AUV.AK1.1, COOMET.AUV.AK1, and COOMET.AUV.AK1.1
MEASURAND : Pressure sensitivity level of LS1P laboratory standard microphones
NOMINAL VALUE : 0 dB
FREQUENCY : 1000 Hz
x_{i} : result of measurements carried out by laboratory i (designated as M_{i} in the CCAUV.AK1 Final Report)
The quoted pressure sensitivity levels are the mean of measurements on two microphones, relative to the arithmetic mean value of all such measurement made in this key comparison.
The nominal value is therefore 0 dB, the key comparison reference value (see the equivalence statements).
u_{i} : combined standard uncertainty of x_{i}
The uncertainty quoted in the following table is 2u_{i}, so that it can be given at a resolution consistent with the measured data.
Lab i
x_{i}
/ dB2u_{i }/ dB
NPL
0.01
0.03
CENAM
0.00
0.03
CSIRNML
0.02
0.05
NMIA
0.01
0.04
DPLA
0.00
0.03
NMIJ
0.01
0.04
GUM
0.00
0.03
KRISS
0.00
0.03
NIST
0.02
0.04
NRC
0.03
0.04
PTB
0.01
0.03
VNIIFTRI
0.00
0.05
x_{iEUR} : result of measurements carried out by laboratory i (designated as M_{i} in the EUROMET.AUV.AK1 Final Report)
The quoted pressure sensitivity levels are relative to internal EUROMET reference values, computed as explained on page 3 of the EUROMET.AUV.AK1 Final Report for each frequency, so the nominal value is 0 dB by design.
u_{iEUR} : combined standard uncertainty of x_{iEUR}
The uncertainty quoted in the following table is 2u_{iEUR}, so that it can be given at a resolution consistent with the measured data.
Lab i
x_{iEUR}
/ dB2u_{iEUR }/ dB
NPL
0.00
0.03
DPLA
0.01
0.03
BEV
0.01
0.03
SP
0.01
0.04
IEN
0.02
0.05
PTB
0.01
0.03
UME
0.05
0.05
METAS
0.02
0.03
SMU
0.01
0.04
OMH
0.00
0.07
CMI
0.04
0.03
x_{iAPMP} : result of measurements carried out by laboratory i
The quoted pressure sensitivity levels are relative to internal APMP reference values, computed as explained on page 16 of the APMP.AUV.AK1 Final Report for each frequency, so the nominal value is 0 dB by design.
u_{iAPMP} : combined standard uncertainty of x_{iAPMP}
The uncertainty quoted in the following table is 2u_{iAPMP}, so that it can be given at a resolution consistent with the measured data.
Lab i
x_{iAPMP}
/ dB2u_{iAPMP }/ dB
CMS/ITRI
0.01
0.04
KRISS
0.00
0.03
NIM
0.01
0.05
NIMT
0.01
0.04
NMIA
0.01
0.04
NMLSIRIM
0.01
0.03
NPLI
0.01
0.07
SCL
0.00
0.04
NMIJ
0.01
0.04
x_{iSIM} : result of measurements carried out by laboratory i
The quoted pressure sensitivity levels are relative to internal SIM reference values, obtained as the arithmetic mean of all measurements available for each microphone, see on page 12 of the SIM.AUV.AK1 Final Report, so the nominal value is 0 dB by design.
u_{iSIM} : combined standard uncertainty of x_{iSIM}
The transfer standards were calibrated by the pilot laboratory, NRC, before delivery and after return from a participating laboratory.
Microphone serial number 907045
Lab i
x_{iSIM}
/ dBu_{iSIM }/ dB
NRC
0.02
0.02
NIST
0.02
0.02
NRC
0.02
0.02
CENAM
0.03
0.025
NRC
0.01
0.02
INMETRO
0.05
0.025
NRC
0.01
0.02
INTI
0.01
0.025
NRC
0.00
0.02
Microphone serial number 1734004
Lab i
x_{iSIM}
/ dBu_{iSIM }/ dB
NRC
0.00
0.02
NIST
0.02
0.02
NRC
0.01
0.02
CENAM
0.00
0.025
NRC
0.00
0.02
INMETRO
0.00
0.025
NRC
0.00
0.02
INTI
0.01
0.025
NRC
0.00
0.02
x_{KIMLIPI(APMPK1.1)}: result of measurements carried out by KIMLIPI obtained as the difference between KRISS and KIMLIPI as explained in section 8 of the APMP.AUV.AK1.1 Final Report.
U_{KIMLIPI(APMPK1.1)} : expanded uncertainty of x_{KIMLIPI(APMPK1.1)}
x_{KIMLIPI(APMPK1.1)} = 0.01 dB
U_{KIMLIPI(APMPK1.1)} = 0.07 dB
x_{iCOO} : result of measurements carried out by laboratory i participant in COOMET.AUV.AK1
u_{iCOO} : combined standard uncertainty of x_{iCOO}
Microphone 4160.2302519
Lab i
x_{iCOO}
/ dB2u_{iCOO }/ dB
PTB
26.92
0.03
GUM
26.95
0.03
UME
26.93
0.06
SMU
26.93
0.04
VNIIFTRI
26.96
0.04
Microphone 4160.2302521
PTB
26.90
0.03
GUM
26.93
0.03
UME
26.90
0.06
SMU
26.91
0.04
VNIIFTRI
26.93
0.04
Lab i
x_{ i}_{COO }/ dB
2u_{i}_{COO }/ dB
x_{i}_{COO.1} : result of measurements carried out by laboratory i participant in COOMET.AUV.AK1.1
u_{iCOO.1} : combined standard uncertainty of x_{i}_{COO.1}
Microphone 4160.2302520
PTB
26.93
0.03
DNDI
26.94
0.04
Lab i
x_{ i}_{COO.1}
/ dB2u_{i}_{COO.1}
/ dB
CCAUV.AK1, EUROMET.AUV.AK1, APMP.AUV.AK1, SIM.AUV.AK1, APMP.AUV.AK1.1, COOMET.AUV.AK1, and COOMET.AUV.AK1.1
MEASURAND : Pressure sensitivity level of LS1P laboratory standard microphones
NOMINAL VALUE : 0 dB
FREQUENCY : 63 Hz to 8 kHz
x_{i} : result of measurements carried out by laboratory i (designated as M_{i} in the CCAUV.AK1 Final Report)
The quoted pressure sensitivity levels are the mean of measurements on two microphones, relative to the arithmetic mean value of all such measurement made in this key comparison.
The nominal value is therefore 0 dB, the key comparison reference value (see the equivalence statements).
u_{i} : combined standard uncertainty of x_{i}
The uncertainty quoted in the following table is 2u_{i}, so that it can be given at a resolution consistent with the measured data.
Click on the following links to access CCAUV.AK1 data obtained:
 from 63 Hz to 2000 Hz, and
 from 2500 Hz to 8000 Hz.
x_{iEUR} : result of measurements carried out by laboratory i (designated as M_{i} in the EUROMET.AUV.AK1 Final Report)
The quoted pressure sensitivity levels are relative to internal EUROMET reference values, computed as explained on page 3 of the EUROMET.AUV.AK1 Final Report for each frequency, so the nominal value is 0 dB by design.
u_{iEUR} : combined standard uncertainty of x_{iEUR}
The uncertainty quoted in the following table is 2u_{iEUR}, so that it can be given at a resolution consistent with the measured data.
Click on the following links to access EUROMET.AUV.AK1 data obtained:
 from 63 Hz to 2000 Hz, and
 from 2500 Hz to 8000 Hz.
Results obtained at 10 kHz are not displayed because they cannot be linked to CCAUV.AK1 results, for which no data were taken at this frequency. They can be found in Table 2 on page 4 of the EUROMET.AUV.AK1 Final Report.
Key comparison APMP.AUV.AK1
x_{iAPMP} : result of measurements carried out by laboratory i
The quoted pressure sensitivity levels are relative to internal APMP reference values, computed as explained on page 16 of the APMP.AUV.AK1 Final Report for each frequency, so the nominal value is 0 dB by design.
u_{iAPMP} : combined standard uncertainty of x_{iAPMP}
The uncertainty quoted in the following table is 2u_{iAPMP}, so that it can be given at a resolution consistent with the measured data.
Click on the following links to access APMP.AUV.AK1 data obtained:
 from 63 Hz to 2000 Hz, and
 from 2500 Hz to 8000 Hz.
Key comparison SIM.AUV.AK1
x_{iSIM} : result of measurements carried out by laboratory i
The quoted pressure sensitivity levels are relative to internal SIM reference values, obtained as the arithmetic mean of all measurtements available for each microphone, see on page 12 of the SIM.AUV.AK1 Final Report, so the nominal value is 0 dB by design.
u_{iSIM} : combined standard uncertainty of x_{iSIM}
The transfer standards were calibrated by the pilot laboratory, NRC, before delivery and after return from a participating laboratory.
Click on the following links to access SIM.AUV.AK1 data obtained from 125 Hz to 8000 Hz with:
 Microphone serial number 907045 , and
 Microphone serial number 1734004.
x_{KIMLIPI(APMPK1.1)}: result of measurements carried out by KIMLIPI obtained as the difference between KRISS and KIMLIPI as explained in section 8 of the APMP.AUV.AK1.1 Final Report.
U_{KIMLIPI(APMPK1.1)} : expanded uncertainty of x_{KIMLIPI(APMPK1.1)}
From 63 Hz to 8000 Hz, the values of the difference between KRISS and KIMLIPI and their expanded uncertainties can be found in Table 4 of the APMP.AUV.AK1.1 Final Report.
x_{iCOO }: result of measurements carried out by laboratory i participant in COOMET.AUV.AK1
u_{iCOO }: combined standard uncertainty of x_{i}_{COO}
From 63 Hz to 10000 Hz, the values of the pressure sensitivity levels reported by laboratory i for the two microphone 4160.1302519 and 4160.2302521 are given in Table 2 and 3, together with the 2u_{iCOO }values in Table 4 of COOMET.AUV.AK1 Final Report.
x_{iCOO .1}: result of measurements carried out by laboratory i participant in COOMET.AUV.AK1.1
u_{iCOO.1 }: combined standard uncertainty of x_{i}_{COO.1}
From 63 Hz to 10000 Hz, the values of the pressure sensitivity levels and associated uncertainties reported by laboratory i for microphone 4160.1302520 are given in Table 1 of COOMET.AUV.AK1.1 Final Report.