EXHIBIT 16 April 29, 1998 GRANT THORNTON LLP Accountants and Management Consultants The U.S. Member Firm of Grant Thornton International Securities and Exchange Commission Washington, D.C. 20549 Re: Sonics & Materials, Inc. File No. 0-20573 Dear Sir or Madam: We have read Item 4 of the Form 8-K of Sonics & Materials, Inc. dated April 24, 1998, and agree with the statements contained therein. Very truly yours, /s/ Grant Thornton LLP