Recently I have been refurbishing a broken Bronica S2, (mostly working now) - people say it has the loudest shutter, and I've always wondered what could be louder than my Hasselblad 2000FC/M, and now I can compare them. And since Sirius started this thread, I may as well upload the shutter sound I have as well.
GEEK warning: skip if necessary:
Loudness was measured using a "reasonably" calibrated db meter on an iPhone. Sounds were measured and recoded outside with the microphone 30cm directly above the center of the shutter with the camera on a tripod, set to 1/125th and F8, with the standard lens. It was done this way so it could be repeated by anyone else, as not everyone has access to studio db meters or an anechoic room. Because it is spring, you do get bird sounds and some wind, the ambient background sound was on the order of 40~50db, which is not insignificant. 4~5 reading were averaged, and due to the equipment and setup, there is a few db variation. The measurement location reflects what the photographer hears - I also tried measurements 1m in front of the camera (subject's perspective), but those are quieter and more subject to ambient noise.
END GEEK
As there is some variation in the measurements, please consider them as such, but the relative numbers reflect the what I hear. Click below to download/hear the recordings, and keep in mind the recording does not do the cameras justice, they sound much fuller and different in person.
Hasselblad 503CX: 77db
Hasselblad 2000FC/M; 84db
Bronica S2: 81db
Bronica EC TL: 78db
Kiev-88: 80db
Pentacon Six TL; 72db
Yashica Mat 124g: 60db
Note: the squeak you hear at the end of the shutter on the Pentacon Six is a bird, not the shutter. I added the Yashica Mat as a non SLR lens shutter reference.
In person, the Hasselblad 2000FC/M has a very metallic clang, which makes it sound louder than it measures.