Dear List, I hope my email finds you in the best of activities. 1. I am working on a project for dolphin conservation and behavioural studies in Pakistan. For this purpose we want to buy hydrophones and recording equipment (electronic equipment) to record broadband acoustics of fresh water dolphins and marine mammals. 2. As we are conducting long term monitoring and funding is an issue, for long run, I am also interested in getting suggestions/guidance on in-home preparation of hydrophones and electronic equipment for recording. Though I work in CSE faculty, I hope that I can get assistance from Mechanical & Electronics faculty in my university, based on your suggestions. [In this regard, particularly an advice on prices & companies selling broad-band PZT/piezo-ceramic elements and reliable open-source design for high-sampling (3 MHz sampling rate) data loggers or A/D converter circuits is requested]. I 'll be extremely thankful for your kind guidance on requested information on my email address.(I 'll happy to share the summary/list of guidance papers received after 2 weeks of this email). sincerely, s.