NONCOMPETITION AGREEMENT


         AGREEMENT dated January 25, 1999, between SONUS-USA, INC., a Washington
corporation ("SONUS") and GREGORY J. FRAZER ("Employee").

                                    RECITALS

                  A. SONUS entered into stock purchase  agreements with Employee
for the following companies on various dates:

                     Hearing Care Associates-Northridge, Inc.;
                     Hearing Care Associates-Glendale, Inc.;
                     Hearing Care Associates-Glendora, Inc.;
                     Hearing Care Associates-Los Angeles, Inc.;
                     Hearing Care Associates-Arcadia, Inc.;
                     Hearing Care Associates-Sherman Oaks, Inc.;
                     Audio-Vestibular Center, Inc.;
                     Hearing Care Associates-Lancaster, Inc.;
                     Hearing Care Associates-Santa Monica, Inc.;
                     Hearing Care Associates-Inglewood, Inc.; and
                     Hearing Care Associates-Montclair, Inc.

(collectively, "HCA Companies");

                  B. In connection with the purchase of HCA Companies,  Employee
and SONUS entered into certain  noncompetition  agreements  prohibiting employee
from competing with SONUS in certain geographic areas.

                  C. Employee was a principal shareholder, a member of the board
of  directors,  and a  key  executive  officer  of  HCA  Companies.  Because  of
Employee's  detailed  knowledge of HCA Companies and  Employee's  reputation and
relationship with patients, customers, suppliers,  distributors,  employees, and
other parties doing business with HCA Companies.  SONUS  recognizes the Employee
acknowledges  the  detrimental  effect on and the  decrease  in value of the HCA
Companies  that would  result if Employee  were to enter into  competition  with
SONUS.

                  D. SONUS and Employee have  determined  that it is in the best
interest of each of them to expand the  geographic  area  covered by  Employee's
covenant  not to  compete.  Employee  and SONUS  acknowledge  that the  expanded
covenant not to compete is in connection with the sale of the HCA Companies.

<PAGE>

                                      TERMS

                  In  consideration  of  the  covenants  and  agreements  of the
parties herein contained, the parties agree as follows:

                  1. Covenant Not to Compete.  For a period of three years after
the date Employee's  employment with SONUS  terminates for any reason,  Employee
will not  directly  or  indirectly  engage  in any  Competitive  Activities  (as
hereinafter  defined)  within the Territory (as hereinafter  defined).  The term
"Competitive Activities" as used herein shall mean:

                  (i)  directly or  indirectly  engaging  in,  continuing  in or
         carrying  on any  business  substantially  similar  to that  heretofore
         conducted  by SONUS,  including  owning or  controlling  any  financial
         interest  in any  corporation,  partnership,  firm  or  other  form  of
         business  organization  which  competes  with SONUS or is engaged in or
         carries on any aspect of such  business or any  business  substantially
         similar thereto;

                  (ii)  consulting  with,  advising or assisting in any way with
         respect to the  operation  of any  hearing  care  business  of the type
         conducted  by  SONUS or any  business  substantially  similar  thereto,
         whether or not for consideration, or any corporation, partnership, firm
         or other  business  organization  which is now,  becomes or is actively
         planning to become a competitor of SONUS including, but not limited to,
         advertising or otherwise endorsing the products of any such competitor;
         soliciting  customers or otherwise  serving as an intermediary  for any
         such competitor; loaning money or rendering any other form of financial
         assistance to or engaging in any form of business  transaction on other
         than an arm's length basis with any such competitor; or

                  (iii)  enticing away or otherwise  persuading  any employee of
         SONUS to alter,  modify or terminate his or her relationship with SONUS
         as an employee

provided  that this  covenant  shall not preclude  the  ownership by Employee of
securities of corporations which are listed on a national securities exchange or
traded in the national  over-the-counter market in amounts which do not exceed 5
percent of the outstanding shares of any such corporation.

         The parties  agree that the  geographic  scope of this  covenant not to
compete (the "Territory") shall cover the states of Arizona,  New Mexico and the
area of  California  which lies  north of Santa  Barbara  (except  for a 20 mile
radius  from  Saratoga,  California  and a 10 mile  radius  from San  Francisco,
California).  In the event a court of competent jurisdiction determines that the
provisions of this covenant not to compete are excessively broad as to duration,
geographical scope or activity, it is expressly agreed that this covenant not to
compete  shall  be  construed  so that the  remaining  provisions  shall  not be
affected,  but shall  remain in full force and  effect,  and any such  overbroad
provisions  shall  not be  deemed,  without  further  action  on the part of any
person, to be modified, amended and/or limited, but only to the extent necessary
to render the same valid and enforceable in such jurisdiction.

                                      -2-
<PAGE>

                  2. Covenant of Confidentiality. Employee shall not at any time
subsequent to the date hereof,  except as explicitly requested by SONUS, (i) use
for any purpose,  (ii)  disclose to any person,  or (iii) keep or make copies of
documents,  tapes,  discs or program  containing,  any confidential  information
concerning  the  operations  of  SONUS.  For  purposes   hereof,   "confidential
information" shall mean and include, without limitation,  trade rights, customer
lists  and  information,   and  all  other  information  concerning  operations,
equipment, products, marketing and distribution methods not previously disclosed
to the public directly by SONUS or otherwise in the public domain.

                  3. Consideration. In consideration of Employee's covenants set
forth  herein,  SONUS  will pay to  Employee  (so long as he is not in  material
breach of the terms hereof) the sum of $6,303 per month on the first day of each
month during the period beginning with January 1, 1999 and ending with September
1, 2001.  Under no  circumstances  shall SONUS be relieved of its  obligation to
make the  foregoing  payments  pursuant  to this  Agreement  as a result  of the
termination  of  Employee's  employment  with SONUS,  regardless of whether such
termination  is by SONUS or  Employee  and  regardless  of whether it is with or
without good cause.

                  4. Equitable  Relief of Violations.  Employee  agrees that the
provisions and restrictions contained in this Agreement are necessary to protect
the legitimate continuing interests of SONUS and that any violation or breach of
these  provisions will result in irreparable  injury to SONUS for which a remedy
at law would be inadequate  and that, in addition to any relief at law which may
be available to SONUS for such  violation or breach and  regardless of any other
provision contained in this Agreement, SONUS shall be entitled to injunctive and
other equitable relief as a court may grant after considering the intent of this
Agreement.

                  If  Employee  violates  the  terms  of  this  Agreement,  such
violation  shall  constitute  a breach  of all other  noncompetition  agreements
entered  into in  connection  with the  purchase  of HCA  Companies  (the "Prior
Agreements"),  and if Employee violates the terms of the Prior Agreements,  such
violation shall constitute a breach of this Agreement.

                  If SONUS violates the terms of this Agreement,  such violation
shall  constitute a breach of the Prior  Agreements,  and if SONUS  violates the
terms of the Prior Agreements,  such violation shall constitute a breach of this
Agreement.

                  5. Assignment.  Neither this Agreement nor any interest herein
may be assigned by Employee.  SONUS may freely assign this Agreement and any and
all interests herein to any "affiliate" (as such term is currently defined under
the  Securities  Act of 1934, as amended),  or in connection  with the transfer,
directly  or  indirectly,  of all  or  substantially  all,  of  the  assets  and
businesses acquired from Employee.

                                      -3-
<PAGE>

                  6. GENERAL.

                  6.1.  Governing  Law. This  Agreement  shall be subject to and
governed  by the laws of the State of  California,  excluding  any choice of law
rules that may direct the application of the laws of another jurisdiction.

                  6.2. Binding Effect.  This Agreement shall be binding upon and
inure to the benefit of Employee  and SONUS and their  respective  heirs,  legal
representatives, executors, administrators, successors, and permitted assigns.

                  6.3. Integration; Amendment; Waiver. This Agreement sets forth
all of the  understandings of the parties with respect to its subject matter and
supersedes  any and all other  agreements,  either  oral or in  writing,  of the
parties with respect to the subject  hereof.  No change or  modification of this
Agreement shall be valid unless in writing and signed by the party against which
it is to be  enforced.  No waiver of any  provision of this  Agreement  shall be
valid unless written and signed by the person or party to be charged.

                  6.4. Severability. If any provision of this Agreement shall be
determined to be  unenforceable  because the terms are excessive or unreasonable
then  such  provision  shall be  reduced  to the  maximum  reasonable  limit and
enforced  as  reduced.  In the  event  that  any one or  more of the  provisions
contained in this  Agreement  shall be  determined  to be invalid,  illegal,  or
unenforceable  in any respect,  the  enforceability  of such provisions in every
other respect and of the remaining provisions of this Agreement shall not in any
way be impaired.

                  6.5. Headings. The headings of this Agreement are inserted for
convenience  only  and  are  not to be  considered  in the  construction  of the
provisions hereof.

                  6.6. Attorney Fees. In the event a suit or action is commenced
for the  interpretation  or enforcement of this Agreement,  the prevailing party
shall be  entitled  to collect  from the losing  party in addition to all of the
costs and expenses, reasonable attorney fees at trial and on appeal.

                                      -4-
<PAGE>

         IN WITNESS  WHEREOF  the  parties  have  executed  and  delivered  this
Agreement as of the date first above written.

                                        SONUS-USA, INC.


                                        BY: /s/ Scott E. Klein
                                            Scott E. Klein
                                            Executive Vice President


                                        EMPLOYEE


                                        /s/ Gregory J. Frazer
                                        Gregory J. Frazer