Naval Research Laboratory, Attn: Code 3230, 4555 Overlook Avenue, SW, Washington, DC 20375-5326

58 -- ACOUSTIC PROJECTION SYSTEM FOR ACTIVE MEASUREMENTS SOL N00173-00-R-CB02 POC Contract Specialist, Cheri R. Burkhardt, Code 3230.CB (202) 767-6542, Contracting Officer, Carol A. Parnell, Code 3230.CP (202)767-6542 WEB: http://heron.nrl.navy.mil/contracts/rfplist.htm, http://heron.nrl.navy.mil/contracts/rfplist.htm. This notification is in response to questions that came about from the previous synopsis, which appeared in the June 14, 2000 edition of the Commerce Business Daily and to extend the closing date when offers are due to the government. The following are the stated questions with the answer to each question: Question 1: With regard to the reply to Question 10, CBD announcement of 14 June 2000. If the source level definition is a spectrum level and 210 dB is needed in each 1 Hz band over a 2450 Hz band (70% of the frequency range from 1.5 to 5.0 kHz), the total sound pressure level would be 210 + 10 log (2450) = 244 dB re 1 uPa at 1 m, assuming no correlation between each 1 Hz increment. Array directivity index is frequency dependent but take the case in the middle of the frequency range where the array Dl is on the order of 8 dB. The acoustic power is SPL -- 170.8 -- Dl = 65 dB re 1 W or 3.2 megawatts. Is this what was intended and how does it relate to the reply to Question 5 that states 440V at 50 A or 22 kilowatts of ship's power is available to power the system? Answer to Question 1: The reply to question 10 was not what was intended. The source level intended is indeed a "band level" and not a source spectrum level. Hence, for the broadband signal of your example, the total sound pressure level would be 210 dB re 1 microPascal at 1 meter, assuming no correlation between each 1-Hz increment, with the acoustic power equal to 1.3 kilowatts. Question 2: In Section 3.2.d, do you mean 10% maximum duty cycle? As stated in the solicitation, the "minimum" is 10% which implies that the maximum could be continuous. Answer to Question 2: The phrase ". . . with a minimum duty cycle of 10%" in Section 3.2.d should be ". . . with duty cycles of up to and including 10%". Question 3: There is a discrepancy between the CLNs list and Attachment 1. On the CLN list, Projection Elements are required and Increasing Directionality is not. Answer to Question 3: The CLN list, Option 4 (0007) is now titled "Directionality Enhancement". Exhibit A (revised) -- Contract Data Requirements List, DD1423, Pages 2, Attachment No. 1 (revised), Specification for an Acoustic Projection System for Active Measurements, Pages 6 can be located at http://heron.nrl.navy.mil/contracts/rfplist.htm. The synopsis is modified to state offers are due no later than 4:00 P.M. E.S.T. on 30 June 2000. URL http://heron.nrl.navy.mil/contracts/rfplist.htm Posted 06/22/00 (W-SN467453). (0174)

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