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                                                                  Exhibit 10.21


                    "THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN
                    REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR
                    THE SECURITIES LAW OF ANY STATE. THE SECURITIES MAY NOT BE
                    SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF
                    EFFECTIVE REGISTRATION STATEMENTS OR AN OPINION OF COUNSEL
                    ACCEPTABLE TO THIS COMPANY THAT REGISTRATION IS NOT
                    REQUIRED."


                              ROCKFORD CORPORATION

             8.5% CONVERTIBLE SUBORDINATED DEBENTURE DUE MAY 1, 2002

$1,760.00                                                            May 1, 1995

1     PAYMENT OF PRINCIPAL AND INTEREST. Rockford Corporation, an Arizona
      corporation (the "Company"), for value received, promises to pay to Mark
      Albers or transferee, (the "Holder") the principal amount of $1,760.00 on
      May 1, 2002 and to pay interest thereon at the rate of eight and one-half
      percent (8.5%) per annum. Interest will accrue from the date hereof and
      will be paid quarterly, on each January 15th, April 15th, July 15th, and
      October 15th hereafter (commencing on July 15, 1995) until the principal
      is fully paid. Interest will be paid on the basis of a 360-day year of
      twelve 30-day months.

2     REDEMPTION PRIOR TO MATURITY. Subject to the following conditions, the
      Company may, at its option, redeem all or part of this Debenture prior to
      maturity at a redemption price of par (plus any interest accrued but
      unpaid to the date fixed for redemption).

      2.1   Conditions. The Company may redeem this Debenture only after (a) the
            Company's Common Stock becomes publicly traded and trades at a bid
            or closing price at least equal to one hundred fifty percent (150%)
            of the then applicable Conversion Price of this Debenture for a
            period of 30 consecutive trading days or (b) the sale of all or
            substantially all of the Company's business and assets to, or the
            merger or consolidation of the Company with or into, any company
            whose stock is publicly traded and whose stock trades at a bid or
            closing price at least equal to one hundred fifty percent (150%) of
            the then applicable Conversion Price of this Debenture for a period
            of 30 consecutive trading days.

      2.2   Notice of Redemption. The Company must give notice of a redemption
            not less than thirty (30) days, but not more than ninety (90) days,
            before the date fixed for redemption. By the date fixed for
            redemption, the Holder must surrender this Debenture to the Company
            at its principal executive offices in exchange for payment therefor.
            Upon due tender of the redemption price by the Company, this
            Debenture will not be deemed to be outstanding for any purpose
            subsequent to the close of business on the date fixed for
            redemption.
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3     SUBORDINATION AND PRIORITY. The indebtedness evidenced by this Debenture,
      including the principal and accrued interest, is expressly subordinate and
      subject in right of payment and upon liquidation to the prior payment in
      full of all "Senior Debt," whether now outstanding or hereafter created,
      incurred, assumed, or guaranteed.

      3.1   Definition of "Senior Debt". The term "Senior Debt" means the
            principal, premium (if any), and interest on (a) indebtedness (other
            than this Debenture or any previously subordinated debenture) of the
            Company evidenced by notes or similar obligations for money borrowed
            from or guaranteed to persons, firms, or corporations which engage
            in lending money, including, but without limitation, individuals,
            banks, trust companies, insurance companies and other financing
            institutions, and charitable trusts, pension trusts, and other
            investing entities or organizations, (b) indebtedness of the Company
            evidenced by notes or debentures issued under the provisions of an
            indenture or similar instrument between the Company and a bank or
            trust company, (c) the indebtedness of the Company evidenced by the
            Company's Senior Notes in an aggregate principal amount of
            $2,000,000 (due January 12, 1998) and $1,680,000 (due February 3,
            1999), and (d) indebtedness incurred, assumed or guaranteed by the
            Company in connection with the acquisition by it of any property or
            asset unless, in each case, by the terms of the instrument creating
            or evidencing the indebtedness it is expressly provided that such
            indebtedness is not superior in right of payment to this Debenture.

      3.2   Exclusions from Senior Debt. Senior Debt excludes, and the
            indebtedness evidenced by this Debenture is expressly senior and
            entitled to priority in payment and upon liquidation with respect
            to, all capital stock of the Company. Senior Debt excludes, and the
            indebtedness evidenced by this Debenture is expressly of equal
            priority in payment and upon liquidation with respect to, (a)
            indebtedness outstanding on the original issue date of this
            Debenture and convertible into shares of the Company's Common Stock
            and (b) any indebtedness issued after the date of this Debenture and
            convertible into shares of the Company's Common Stock.

4     EVENTS OF DEFAULT. An Event of Default will be deemed to occur upon the
      occurrence of any of the following events:

      4.1   Default in the payment of interest on this Debenture when it becomes
            due and payable, and continuance of such default for a period of ten
            (10) days after notice;

      4.2   Default in the payment of the principal of this Debenture when it
            becomes due and payable;

      4.3   Default by the Company under an acceleration prior to maturity of,
            or the failure to pay at maturity, any third party indebtedness of
            the Company aggregating $250,000 or more for a period of thirty (30)
            days after the same may become payable;


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      4.4   The failure of the Company to comply, for a period of 30 days after
            notice of default, with any affirmative or negative covenant
            contained in the Purchase Agreement of even date herewith between
            the Company and the original Holder hereof;

      4.5   The failure of the Company to pay final judgments (not covered by
            insurance or then subject to any appeal) aggregating $500,000 or
            more for 30 days;

      4.6   The entry of a decree or order by a court having jurisdiction
            adjudging the Company a bankrupt or insolvent, or approving as
            properly filed a petition seeking reorganization, arrangement,
            adjustment, or composition of or in respect of the Company under the
            Federal Bankruptcy Act or any other applicable Federal or State law,
            or appointing a receiver, liquidator, assignee, trustee, or other
            similar official of the Company or of any substantial part of its
            property, or ordering the winding up or liquidation of its affairs,
            and the continuance of any such decree or order unstayed and in
            effect for a period of 60 days; or

      4.7   The institution by the Company of proceedings to be adjudicated a
            bankrupt or insolvent, or the consent by it to the institution of
            bankruptcy or insolvency proceedings against it, or the filing by it
            of a petition or answer or consent seeking reorganization or relief
            under Federal or State law, or the consent by it to the filing of
            any such petition or to the appointment of a receiver, liquidator,
            assignee, trustee, or other similar official of the Company or of
            any substantial part of its property, or the making by it of an
            assignment for the benefit of creditors, or the admission by it in
            writing of its inability to pay its debts generally as they become
            due, or the taking of corporate action by the Company in furtherance
            of any such action.

5     RIGHTS UPON DEFAULT; ACCELERATION OF INDEBTEDNESS. Upon the occurrence of
      an Event of Default:

      5.1   The entire outstanding balance of the Debenture, including the
            entire balance of principal and all accrued interest, will
            accelerate and become immediately due and payable upon written
            notice to the Company by the Holder; and

      5.2   The Company may not pay dividends or make distributions to holders
            of any class of its stock, or redeem or repurchase all or any part
            of any class of its stock.

6     CONVERSION OF DEBENTURE. This Debenture is convertible, at the option of
      the Holder, into shares of the Company's Common Stock on the following
      basis:

      6.1   Conversion Price. A conversion may be made, at any time before the
            close of business on the business day before the maturity or
            redemption date, at the rate of $10.50 per share, subject to
            adjustment as provided in this Debenture (the "Conversion Price").
            The Company is not required to issue fractional shares of Common
            Stock or other capital stock upon conversion of this Debenture and,
            in lieu thereof, will pay a cash adjustment based upon the then
            current fair market


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            value of the Common Stock as determined by the Board of Directors on
            the last business day before the date of conversion.

      6.2   Adjustment Based Upon Stock Dividends Combination of Shares or
            Recapitalization. The Conversion Price and the number of Shares will
            be adjusted if the Company, at any time after the original issuance
            of this Debenture,

            (a)   pays a stock dividend on its Common Stock,

            (b)   subdivides its outstanding shares of Common Stock into a
                  greater number of shares,

            (c)   combines its outstanding shares of Common Stock into a smaller
                  number of shares,

            (d)   issues by reclassification of its shares of Common Stock any
                  other special capital stock of the Company, or

            (e)   distributes to all holders of its Common Stock evidences of
                  indebtedness or assets (excluding cash dividends) or rights or
                  warrants to subscribe for Common Stock (other than those
                  mentioned above).

            On or after the occurrence of an event or events requiring
            adjustment of the Conversion Price, the Holder upon surrender of
            this Debenture for conversion will be entitled to receive the number
            of shares of Common Stock or other securities of the Company which
            the Holder would have owned or been entitled to receive had this
            Debenture been converted immediately before the happening of the
            event requiring adjustment of the Conversion Price.

      6.3   Adjustment Based Upon Stock Issuances. The Conversion Price will be
            adjusted if, at any time after the original issuance of this
            Debenture, the Company issues Common Stock, issues rights or
            warrants to subscribe for or purchase Common Stock, or issues
            securities convertible into or exchangeable for Common Stock at less
            than the Conversion Price. Upon the occurrence of an event or events
            requiring adjustment of the Conversion Price under this section the
            Conversion Price will be adjusted to be equal to the price of the
            new issue. An adjustment under this section will not increase the
            number of shares of Common Stock, or other securities, which the
            Holder will be entitled to receive upon surrender of this Debenture
            for conversion, but will only reduce the Conversion Price which the
            Holder must pay to acquire such Common Stock or other securities.
            Any amount of this Debenture not required to be used in a
            conversion, because of an adjustment of the Conversion Price under
            this section, must be paid by the Company to the Holder upon any
            redemption or upon maturity of this Debenture.

      6.4   Adjustment Based Upon Merger or Consolidation. In case of any
            consolidation or merger to which the Company is a party (other than
            a merger in which the Company is the surviving entity and which does
            not result in any reclassification


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            of or change in the outstanding Common Stock of the Company) or in
            case of any sale or conveyance to another person, firm, or
            corporation of the property of the Company as an entirety or
            substantially as an entirety, the Holder will have the continuing
            right to convert this Debenture into the kind and amount of
            securities and property (including cash) receivable upon such
            consolidation, merger, sale, or conveyance by a holder of the number
            of shares of Common Stock into which this Debenture might have been
            converted immediately before the consolidation, merger, sale, or
            conveyance.

      6.5   No Adjustment for Outstanding Conversion and Option Rights and
            Certain Other Securities. Notwithstanding any other section of this
            Agreement, no adjustment of the Conversion Price will be made upon
            the issuance by the Company of

            (a)   Common Stock upon conversion or exchange of securities
                  convertible or exchangeable into Common Stock and outstanding
                  on or before the date of this Debenture,

            (b)   Common Stock upon exercise of any employee's stock option
                  outstanding on or before the date of this Debenture, or

            (c)   Common Stock or securities convertible into Common Stock, not
                  amounting to more than 10% of the Company's issued and
                  outstanding Common Stock, issued after the date of this
                  Debenture pursuant to an employee benefit plan of the Company.

      6.6   Exercise of Conversion Privilege. The Conversion Privilege is
            exercisable by the Holder upon written notice to the Company (or its
            successor) and the surrender of this Debenture in exchange for the
            number of shares of Common Stock (or other securities and property,
            including cash, in the event of an adjustment of the Conversion
            Price) into which this Debenture is convertible based upon the
            Conversion Price. Conversion rights will expire at the close of
            business on the business day before the maturity or redemption date.

7     CORPORATE STATUS OF SHARES TO BE ISSUED. All shares of the Company's
      Common Stock (or other securities in the event of an adjustment of the
      Conversion Price) issued upon the conversion of this Debenture will, upon
      issuance, be fully paid and nonassessable.

8     ISSUANCE OF STOCK CERTIFICATE. Upon conversion of this Debenture, the
      Company will forthwith issue to the Holder a certificate or certificates
      representing the number of shares of its Common Stock (or other securities
      in the event of an adjustment of the Conversion Price) to which the
      conversion relates.

9     STATUS OF HOLDER OF DEBENTURE. This Debenture does not entitle the Holder
      to any voting rights or other rights as a shareholder of the Company. No
      dividends are payable or accrue in respect of this Debenture, or the
      securities issuable upon conversion, unless and until this Debenture is
      converted. Upon the conversion of this Debenture, the Holder will (to the
      extent permitted by law) be deemed to be the holder of record of the
      shares of


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      Common Stock issuable upon conversion, notwithstanding that the stock
      transfer books of the Company are then closed or that the certificates
      representing the shares of Common Stock are not then actually delivered.

10    LOSS OR DESTRUCTION OF DEBENTURE. The Company will execute and deliver a
      new debenture of like tenor and date upon receipt by the Company of
      evidence satisfactory to it of the loss, theft, destruction, or mutilation
      of this Debenture and (a) in the case of loss, theft, or destruction, of
      an indemnity by the Holder, (b) in case of any transfer, upon such terms
      as are satisfactory to the Company, or (c) in the case of mutilation, upon
      surrender and cancellation of this Debenture.

11    RESERVATION OF SHARES. The Company will reserve out of its authorized
      shares of Common Stock (and other securities in the event of an adjustment
      of the Conversion Price) a number of shares sufficient to enable it to
      comply with its obligation to issue shares of Common Stock (and other
      securities in the event of an adjustment of the Conversion Price) upon the
      conversion of this Debenture.

12    STATUS UNDER SECURITIES LAWS.

      12.1  No Registration. This Debenture has not been, and the securities
            issuable upon conversion hereof will not be, registered under the
            Securities Act of 1933 (the "1933 Act"), the Arizona Securities Act
            (the "Arizona Act") or the securities laws of any other
            jurisdiction. This Debenture, and such securities, must be held
            indefinitely without any transfer, sale, or other disposition unless
            (a) subsequently registered under the 1933 Act, the Arizona Act and
            the securities laws of any other applicable jurisdiction or (b) in
            the opinion of counsel acceptable to the Company, registration is
            not required under such Acts or laws.

      12.2  Legend. There will be endorsed on this Debenture, and on the
            certificates evidencing any securities issued upon the conversion of
            this Debenture, a legend substantially to the following effect:


                    "THE SECURITIES EVIDENCED BY THIS CERTIFICATE HAVE NOT BEEN
                    REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR
                    THE SECURITIES LAW OF ANY STATE. THE SECURITIES MAY NOT BE
                    SOLD, TRANSFERRED, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF
                    EFFECTIVE REGISTRATION STATEMENTS OR AN OPINION OF COUNSEL
                    ACCEPTABLE TO THIS COMPANY THAT REGISTRATION IS NOT
                    REQUIRED."

      12.3  Restriction on Other Securities. Except in certain limited
            circumstances, the restrictions on the transfer of this Debenture
            will also apply to (a) securities issued upon conversion of this
            Debenture and (b) shares of capital stock or other securities issued
            or otherwise acquired on account of the Debenture (or securities
            issued upon conversion of the Debenture) including, without
            limitation, shares


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            and securities issued or acquired as a result of a stock dividend,
            stock split or exchange, or any distribution of shares or securities
            pursuant to any corporate reorganization, reclassification, or
            similar event.

      12.4  Refusal to Transfer. The Company may refuse to effect a transfer,
            sale or other disposition of this Debenture, or the shares issuable
            upon conversion, by the Holder or its successors or assigns
            otherwise than as expressly permitted by this Debenture.

13    MISCELLANEOUS.

      13.1  Purchase Agreement. This Debenture, and the indebtedness evidenced
            hereby, is issued and incurred subject to the terms of the Purchase
            Agreement between the Company and the original Holder, the terms and
            conditions of which are binding upon any subsequent Holder or
            transferee of this Debenture.

      13.2  Governing Law. This Debenture, and all questions relating to its
            validity, interpretation, performance, and enforcement is governed
            by and will be construed in accordance with the laws of Arizona,
            notwithstanding any Arizona or other conflict-of-law provisions to
            the contrary.

      13.3  Binding Nature of Debenture. This Debenture is binding upon any
            successors and assigns of the Company and will inure to the benefit
            of the Holder and its successors and assigns, except that the Holder
            may not assign or transfer its rights under this Debenture otherwise
            than by gift or bequest, by operation of law, or as expressly
            permitted by this Debenture.

      13.4  Notices. All notices and other communications under this Debenture
            must be in writing and will be deemed given and received when
            delivered or five days after they are deposited in the United States
            mails, first class postage prepaid addressed as set forth in the
            Purchase Agreement. Either party may alter the person, office or
            address to which communications or copies are to be sent by giving
            notice.

      13.5  Amendment and Waivers. Neither this Agreement nor any of its terms
            may be changed, waived, discharged, or terminated except in a
            writing signed by the Company and by holders of more than 50% of the
            outstanding Restricted Securities (as that term is defined in the
            Purchase Agreement).

14    EXECUTION DATE. The Company has caused this Debenture to be duly executed
      on the date written above.


                                    ROCKFORD CORPORATION


                                    By:/s/
                                       ----------------------------------------
                                                      President

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                                    Attest:     /s/
                                           ------------------------------------
                                                      Secretary


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