ES 
F. Basan et al. 
Table 3 Pistonphone-derived sensitivities and corresponding clip levels for the recorders used in 
the HELCOM calibration workshop 
Country/ 
ınstitution Recorder 
Sweden/ Soundtrap 
FOI ST640HF 
Sweden/ Soundtrap 
FOI ST300HF 
Sweden/ Sylence 
FOI LP 
Germany/ Sylence 
BSH ‚LP 
Germany/ | icListen 
BSH 
Denmark/ 
AU 
Estonia/ 
TUT 
195 
190 
Hydrophone 
HTI-96- 
UHF 
In situ 
HTI-92-WB 
HTI-96-min 
In situ 
In situ 
HTI-92-WB 
Sensitivity 
(dB re 1 V/p 
Pa) 
—171.4 
Clip level 
(dB re 1 Pa) 
171.4 
176.8 
Frequency of. 
pistonphone 
ı check (Hz) 
250 
—176.8 
250 
-171.6 
179.6 
1000 
— 169.3 
177.3 
125 
171.8 
181.3 
125 
175.9 
175.9 
250 
156.0 
164.0 
250 
Tank calibration 
— BSH Sylence — FOI ST300HF 
-BSH Sylence (holder) — FO] ST640HF 
—- BSH icListen — FO Sylence 
‚AU ST600HF — TUT Sylence 
185 
eo’ 
L 
n 180 F 
N 
©, 
> 
@ 1757 
S 
‘5 
170 
165 
60 
277 
20h 
LT la dr a dpa ng 
4000 5000 6000 27000 8000 9000 10000 
Frequency [Hz] 
Fig. 2 Clip levels from the indoor tank calibration (2-10 kHz), indicating maximum level that can 
ve recorded by the different systems before clipping occurs in the data 
The two tank runs of BSH’s Sylence LP differed due to mounting. For Sylence LP 
recorders, the hydrophone is usually decoupled from the recorder body to minimize