<PAGE>   1
                                                                   EXHIBIT 10.33



                              BRIDGE LOAN AGREEMENT


         This Agreement is between Rockford Corporation, an Arizona corporation
("Borrower") and Caroline S. Bartol ("Lender"). Borrower and Lender agree as
follows:

1.       RECITALS.

         1.1.     Borrower Business. Borrower manufactures high quality auto and
                  professional audio equipment, including amplifiers, speakers,
                  "head units," and accessories.

         1.2.     Loan. Borrower has sought and, subject to the conditions in
                  this agreement, Lender has agreed to provide a $2,000,000 loan
                  to Borrower to help finance working capital and general
                  corporate needs of Borrower.

         1.3.     Purpose. The purpose of this Agreement is to set forth the
                  terms of Lender's agreement to lend to Borrower $2,000,000.

2.       LOAN AGREEMENT. Lender will loan Borrower $2,000,000 (the "Loan") on
         the terms set forth in this agreement. Borrower will execute and
         deliver to Lender a promissory note (the "Note") in the form of Exhibit
         A. Lender will advance the amount of the Loan as of the date of this
         Agreement. Borrower will (a) maintain accurate records of the amount
         advanced, payments made, and interest and other charges in connection
         with the Loan and (b) render to Lender on request, and at least
         monthly, an account statement showing such amounts.

3.       USE OF MONIES LOANED. Borrower will use the amount loaned to for
         working capital, to reduce other debt, and to pay trade accounts
         payable.

4.       INTEREST. The outstanding principal and unpaid interest under this
         Agreement will bear interest at the rate of 9% per annum. Interest is
         payable monthly on the first day of each month.

5.       REPAYMENT OF PRINCIPAL. It is intended that this Loan is a "bridge"
         loan in advance of an investment by Lender or its affiliates in
         Borrower of not less than the principal amount of the Loan. The Loan
         will be repaid out of the investment by Lender or its affiliates.
         Borrower will pay the principal on the Note on the earlier of (a)
         receipt of the proceeds of the capital investment in Borrower committed
         by Lender or its affiliates or (b) September 30, 1996.

6.       SUBORDINATION TO BANK LOAN. The Loan is subordinate to Borrower's
         obligations under its loan (the "Bank Loan") with its principal lender,
         First Interstate Bank of Arizona (the "Bank"). All Borrower's
         obligations to Bank must be first paid to Bank in full before any
         payments may be made under this Loan, except for:
<PAGE>   2
         6.1.     payments of interest when due;

         6.2.     payments of principal paid from proceeds of the capital
                  investment by Lender or its affiliates in Borrower; and

         6.3.     payments of principal when due on September 30, 1996, but only
                  if (a) Bank has not given Borrower notice that it is in
                  default or non-compliance under the Bank Loan and (b) the
                  payment of principal would not cause Borrower to be out of
                  compliance under the Bank Loan either (i) as of the date made,
                  (ii) as of the most recent quarterly compliance date under the
                  Bank Loan (assuming the payment had been made on the last day
                  of such quarter), or (iii) as of the next quarterly compliance
                  date under the Bank Loan (based on Borrower's current
                  projected financial statements). If Borrower makes a payment
                  of principal, Borrower will deliver to Lender and Bank a
                  certificate confirming that these conditions are satisfied.

         6.4.     If there is an Event of Default under Section 9.4 below, then
                  Borrower and its officers, assigns, trustee, receiver, and
                  other representative are directed to pay Bank the full amount
                  of the Bank Loan before making any payments to Lender other
                  than payments of principal out of proceeds of the investment
                  by Lender or its affiliates in Borrower.

7.       NO SECURITY. The Loan is unsecured but constitutes a general obligation
         of Borrower.

8.       ADDITIONAL DOCUMENTS. Borrower will execute and deliver to Lender
         additional documents as necessary to carry out the purposes of this
         Agreement.

9.       EVENTS OF DEFAULT. The following events are "Events of Default":

         9.1.     Borrower fails to pay any amount under this Agreement when due
                  and payable;

         9.2.     Borrower fails or neglects to perform, keep, or observe any
                  term, provision, condition, covenant, representation, or
                  warranty contained in this Agreement;

         9.3.     Borrower becomes insolvent; or

         9.4.     A complaint or case is filed by or against borrower under
                  federal bankruptcy laws and is not dismissed within 60 days of
                  filing; Borrower admits to inability to pay or fails to pay
                  Borrower's debts generally as they mature; Borrower makes an
                  assignment for the benefit of creditors; a receiver is
                  appointed for Borrower; or any other insolvency proceedings
                  are instituted by or against Borrower and are not dismissed
                  within 60 days of filing.

                                     - 2 -
<PAGE>   3
10.      ACCELERATION OF OBLIGATIONS AND REMEDIES. If there is an event of
         default, the outstanding Loan balance and all other amounts owed by
         Borrower to Lender will, if Lender elects, become immediately due and
         payable without notice to or demand upon Borrower of any kind. Any
         acceleration, if elected by Lender, is subject to all applicable laws.

11.      USURY SAVINGS CLAUSE. Borrower will not, upon acceleration of maturity
         by Lender or otherwise, be required to pay any interest in excess of
         the maximum amount permitted by law.

12.      MISCELLANEOUS.

         12.1.    Waiver of Defaults. Lender may, in its sole discretion, waive
                  a default or cure at Borrower's expense a default. Any waiver
                  in a particular instance or of a particular default is not a
                  waiver of other defaults or of the same kind of default at
                  another time.

         12.2.    Entire Agreement; Amendments. This Agreement is the entire
                  Agreement of the parties with respect to its subject matter
                  and may not be changed or amended without the written consent
                  of each party.

         12.3.    Severability. If any part (or parts) of this Agreement is
                  invalid, illegal, or unenforceable in any respect, such
                  invalidity, illegality or unenforceability will not effect any
                  other provisions of this Agreement, and this Agreement will be
                  construed as if the invalid, illegal, or unenforceable
                  provision were omitted, provided that such construction and
                  omission is consistent with the general intent of the parties
                  as evidenced by this Agreement considered as an entirety.

         12.4.    Notices. Notices required under this Agreement are effective
                  upon delivery or three days after mailing by registered or
                  certified mail, return receipt requested, to the address of
                  the parties shown on the signature page of this Agreement
                  (which may be changed by notice).

         12.5.    Governing Law. This Agreement is governed by the laws of
                  Arizona.

         12.6.    Assignability. This Agreement may not be assigned without the
                  prior written consent of each party.

         12.7.    Counterparts. This Agreement may be executed in counterparts
                  and all counterparts so executed constitute one Agreement.

         12.8.    Attorneys' Fees. In any proceeding arising under this
                  Agreement, the prevailing party is entitled to recover the
                  attorneys' fees, costs, and expenses in connection with such
                  proceeding.


                                     - 3 -
<PAGE>   4
13.      EXECUTION AND EFFECTIVE DATE. This Agreement is executed and effective
         March 18, 1996.


                                            "BORROWER"

                                            Rockford Corporation


                                             By:      /s/
                                                ----------------------------
                                                     Chief Financial Officer

                                             Address: 648 S. River Drive
                                                      Tempe, Arizona 85281


                                             "LENDER"



                                                       /s/
                                                ----------------------------
                                                      Caroline S.  Bartol

                                             Address: 38415 Sombrero Road
                                                      Carefree, Arizona 85377


                                     - 4 -
<PAGE>   5
                                    EXHIBIT A

                                 PROMISSORY NOTE



Principal Amount: $2,000,000                                      Tempe, Arizona
                                                                  March 18, 1996


             For value received, Rockford Corporation ("Maker") promises to pay
to the order of Caroline S. Bartol ("Lender"), the principal amount stated above
plus interest on the unpaid balance of the principal as hereinafter provided.
This Promissory Note ("Note") is given by Maker to evidence Maker's obligation
to make payments under the Loan Agreement between Lender and Maker of even date
with this Note (the "Agreement").

             INTEREST AND INTEREST PAYMENTS. The outstanding principal under
this Note will bear interest at the rate of 9% per annum. Interest is payable in
monthly installments equal to accrued interest, with the first installment due
on or before May 1, 1996, and each subsequent installment due on or before the
first day of each month thereafter.

             PRINCIPAL PAYMENTS. Maker will pay the principal on the Note on the
earlier of (a) receipt of the proceeds of the capital investment in Maker
committed by Lender or its affiliates or (b) September 30, 1996.

             DEFAULT. A default will occur upon an "Event of Default" as defined
in the Agreement.

             REMEDIES. Upon any Event of Default, the entire principal and any
accrued but unpaid interest will, at Lender's option, become due and payable on
demand and Lender will have any other remedies granted to it under the
Agreement.

             CREDITING OF PAYMENTS. Lender may credit all payments received
first against the accrued but unpaid interest, then against any costs of
collection, then against the unpaid principal then due or delinquent.
<PAGE>   6
             PREPAYMENT. Maker reserves the right to prepay all or any portion
of the principal sum without penalty of any kind, but will pay all accrued but
unpaid interest on the date of such a prepayment.

             FORM OF PAYMENTS. Principal and interest are payable only in lawful
money of the United States of America in immediately available funds.

             ATTORNEYS FEES. If this Note is placed in the hands of an attorney
for collection, Maker promises to pay, in addition to the unpaid principal and
accrued but unpaid interest, the costs of collection including reasonable
attorneys fees.

             WAIVERS. Maker and any endorsers hereof waive demand, notice of
presentment, protest, notice of dishonor and protest, rights of exemption, and
any defense by reason of extension of time or other indulgences granted by
Lender. The obligations under this Note are binding and enforceable upon and
against the successors and assigns of Maker.


                                            "MAKER"

                                            Rockford Corporation


                                            By:    /s/  James M. Thomson
                                               --------------------------------
                                                  Chief Financial Officer

                                     - 2 -