<PAGE>   1
                                                                    EXHIBIT 4.16

                                                                  CPR (USA) INC.

               SECURED NON-NEGOTIABLE CONVERTIBLE PROMISSORY NOTE


<TABLE>
<S>                                             <C>
    US$112,620.55                                Issued:  December 29, 1999
New Principal Amount                            Maturity Date:  June 15, 2001
</TABLE>


        FOR VALUE RECEIVED, SPATIALIZER AUDIO LABORATORIES, INC., a Delaware
corporation ("Maker"), hereby promises to pay under this non-negotiable
convertible promissory note ("Note") to CPR (USA) INC. ("Payee"), the principal
amount of One Hundred Twelve Thousand, Six Hundred Twenty and 55/100 Dollars
(US$112,620.55), which represents the principal of the funds advanced by Payee
and accrued interest thereon from the date of advance through December 29, 1999
("New Principal"), together with interest thereon from December 29, 1999,
according to the following terms and conditions. This instrument is not
negotiable by Payee. All references herein to currency herein shall refer to
United States Dollars. This Note has been secured by the Collateral of Maker
pursuant to the terms of the security agreement (the "Security Agreement"), of
even date hereof, entered into between Maker and Payee.

        1. Interest. Interest shall accrue from the date hereof on the New
Principal outstanding from time to time under this Note, at a rate per annum
equal to ten percent (10%). Interest hereunder shall be computed for the actual
number of days elapsed on the basis of a three hundred sixty (360) day year.
Cash payments of New Principal and interest are payable in lawful money of the
United States of America in same day funds.

        2. Payment Schedule.

               (a) Unless the outstanding New Principal and the interest accrued
thereon shall have sooner been discharged through a conversion into the common
stock, par value $0.01 per share, of Maker ("Common Stock"), or a successor to
Maker as a result of a restructuring or reorganization involving Maker (any such
successor and Maker are collectively referred to as "Maker"), as the case may
be, or through the exercise of a Conversion Option (as defined in Section 3
below), the unpaid New Principal plus interest accrued thereon shall be due and
payable to Payee on the earlier of June 15, 2001 (the "Maturity Date") or upon
the occurrence of an Event of Default as set forth below. In the event that the
outstanding New Principal shall be converted into Common Stock pursuant to
Section 3, then accrued interest due on the outstanding New Principal also shall
be paid in shares of Common Stock pursuant to Section 3 and the number of shares
issued will be adjusted to include interest accrued as of the Conversion Date
(as defined in Section 3(c) below).

               (b) Provided no Event of Default (as set forth below) has
occurred and/or is occurring, the outstanding New Principal and interest accrued
thereon may be prepaid in cash by Maker, in whole or in part, at any time prior
to the Maturity Date (except that portion of the New Principal outstanding
hereunder and interest accrued thereon that is the subject of a Conversion
Notice (as defined in Section 3(c) below) which has previously been sent to
Maker), without premium or penalty of any kind by giving written notice to Payee
(the "Prepayment Notice"). In the


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                                                                  CPR (USA) INC.

event of prepayment pursuant to Section 2(b), Maker shall not be required to pay
unaccrued interest. All payments hereunder shall be applied first to accrued
interest and the balance of such payments shall be applied to the New Principal
amount payable hereunder. Maker shall wire transfer the appropriate amount of
funds to Payee to complete the prepayment, which shall be no later than the
third business day after the Prepayment Notice was received by Payee (the
"Prepayment Date"). Upon facsimile receipt of the Prepayment Notice, Payee's
right to convert New Principal outstanding hereunder and interest accrued
thereon into Common Stock shall terminate and be canceled immediately (the right
to convert shall be immediately reinstated if Maker fails to comply with the
prepayment provisions). In the event that Maker does not wire transfer the
appropriate amount of funds to Payee, on or before the Prepayment Date, or shall
otherwise fail to comply with the prepayment provisions set forth herein, then
it shall have waived its right to prepay any portion of this Note at any time
thereafter. The Prepayment Notice shall set forth (i) the Prepayment Date, (ii)
the Prepayment Price, as defined below, and (iii) the New Principal being
prepaid. The Prepayment Notice shall be irrevocable, and it shall be delivered
by facsimile or mailed, postage prepaid, to Payee at its address as the same
shall appear on the books of Maker. The "Prepayment Price" shall be equal to the
portion or all of the New Principal being prepaid plus all accrued and unpaid
interest due thereon. At the close of business on the Prepayment Date, subject
to Payee's receipt of the applicable Prepayment Price, the portion of this Note
being prepaid shall be automatically canceled and converted into a right to
receive the Prepayment Price. Immediately following the Prepayment Date
(assuming full compliance by Maker with the prepayment provisions set forth
herein), Payee shall surrender its original Note at the office of Maker, and
Maker shall issue to Payee a new Note certificate for the principal amount that
remains outstanding, if any. Notwithstanding the foregoing, Maker shall not be
entitled to send a Prepayment Notice unless it has: (i) the full amount of the
applicable Prepayment Price in cash, available in a demand or other immediately
available account in a bank or similar financial institution; (ii) immediately
available credit facilities, in the full amount of the Prepayment Price with a
bank or similar financial institution; or (iii) a combination of the items set
forth in (i) and (ii) above, aggregating the full amount of the Prepayment
Price.

        3. Conversion.

               (a) Provided no Event of Default (as set forth below) has
occurred and/or is occurring, all of the shares of Common Stock underlying the
Note are then included in an effective Registration Statement, and the closing
bid price of the Common Stock as reported by Bloomberg LP as of the Conversion
Date is greater than the Conversion Price (as defined below), Maker shall have
the option (the "Maker Conversion Option") to convert, at its sole discretion at
any time prior to the Maturity Date, all New Principal outstanding hereunder and
all accrued interest thereon, into fully paid and nonassessable shares of Common
Stock based on the conversion price per share defined below (the "Conversion
Price"). The number of shares of Common Stock to be issued to Payee upon
conversion shall be determined by dividing (i) all New Principal outstanding
hereunder and accrued interest thereon as of the Conversion Date, by (ii) the
Conversion Price, provided, however, that Maker shall not issue to Payee a
fraction of a share of Common Stock and shall instead round the number of shares
of Common Stock issued up to the next whole share of Common Stock. In the event
that Maker does not forward the shares of Common Stock to Payee pursuant to the
conversion delivery provisions set forth below, then it shall have waived its
right to force conversion of any portion of this Note at any time thereafter.
Maker's Conversion Notice shall set forth the New Principal being prepaid.
Maker's Conversion Notice shall be irrevocable, and it shall be delivered


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                                                                  CPR (USA) INC.

by facsimile or mailed, postage prepaid to Payee at its address as the same
shall appear on the books of Maker.

               (b) Payee shall have the option (the "Payee Conversion Option";
the Payee Conversion Option and the Maker Conversion Option are sometimes
collectively referred to herein as "Conversion Options") to convert, at any time
on or after the issuance date of this Note, all or any portion of the New
Principal outstanding hereunder and all accrued interest thereon, into fully
paid and nonassessable shares of Common Stock based on the Conversion Price. The
number of shares of Common Stock to be issued upon conversion shall be
determined by dividing (i) the portion of New Principal outstanding hereunder
and accrued interest thereon as of the Conversion Date, by (ii) the Conversion
Price, provided, however, that Maker shall not issue to Payee a fraction of a
share of Common Stock and shall instead round the number of shares of Common
Stock issued up to the next whole share of Common Stock.

               (c) Maker shall exercise the Maker Conversion Option by
delivering written notice thereof (a "Conversion Notice") to Payee, and Payee
shall exercise the Payee Conversion Option by delivering written notice thereof
(also a "Conversion Notice") to Maker. Any Conversion Notice shall be sent via
facsimile to the telecopier numbers and addresses listed below. The date on
which Maker or Payee shall send a Conversion Notice shall be the "Notice Date".
Maker shall issue and deliver to Payee the applicable number of shares of Common
Stock to Payee no later than three business days after the Notice Date. The date
on which Maker issues shares of Common Stock to Payee pursuant to an exercised
Conversion Option shall be the "Conversion Date".

               (d) After all of the New Principal outstanding and accrued
interest thereon have been converted into shares of Common Stock, all New
Principal and interest payable to Payee under this Note shall be deemed paid in
full, and all obligations hereunder shall be completely satisfied. No later than
ten (10) business days after the last Conversion Date, provided that Maker has
fully complied with the conversion provisions set forth herein, Payee shall
surrender this Note to Maker for cancellation.

               (e) The "Conversion Price" shall be determined on the Conversion
Date, and shall equal the average of the closing bid prices of Common Stock for
the ten (10) consecutive trading days ending on the trading day immediately
preceding the Notice Date, provided, however, that any day on which the
aggregate of the purchases and sales or either of them of Common Stock by Payee
and its affiliates account for greater than twenty-five percent (25%) of that
day's total trading volume (as reported by Bloomberg LP) shall not be counted in
calculating the Closing Price and the parties shall use the immediately
preceding trading day(s) on which this volume limitation has not been exceeded
to determine the ten day period over which the Conversion Price shall be
calculated. Notwithstanding the foregoing, the Conversion Price shall under no
circumstances: (i) be lower than the average of the closing bid prices of Common
Stock for the ten (10) consecutive trading days ending one (1) trading day prior
to the date hereof (the "Floor Price"); or (ii) be higher than 200% of the Floor
Price (the "Ceiling Price"). The "closing bid price" shall mean the last bid
price for Common Stock on the OTC Bulletin Board, as reported by Bloomberg LP.


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                                                                  CPR (USA) INC.

               (f) Provided that Maker is in full compliance with the terms of
this Note, Payee has agreed not to engage in any short sales of any shares of
capital stock of Maker for so long as any New Principal and accrued interest
thereon shall remain outstanding and payable under this Note.

               (g) In the event of any stock split, stock dividend,
reclassification or similar event affecting the Common Stock (each an
"Adjustment Transaction"), then both the Floor Price and the Ceiling Price shall
be adjusted by multiplying them by a fraction, the numerator of which shall be
the number of shares of Common Stock outstanding immediately prior to such
Adjustment Transaction, and the denominator of which shall be the number of
shares of Common Stock outstanding immediately after such Adjustment
Transaction.

               (h) In the event that Maker issues shares of Common Stock
pursuant to an exercised Conversion Option, the shares of Common Stock shall be
issued as restricted securities under federal securities laws and there shall be
an appropriate legend restricting the transfer thereof (if so required under
applicable federal securities laws).

               (i) This Note, and Payee's rights hereunder, are not transferable
or assignable other than to an affiliate of Payee. The foregoing limitation
shall not apply in the event that Maker is not in full compliance with the terms
of this Note and the Transaction Documents (as defined in Section 7(a) below).

        4. Subordination. So long as any portion of this Note remains
outstanding, Maker agrees that neither Maker nor any direct or indirect
subsidiary of Maker shall create, incur, assume, guarantee, secure or in any
manner become liable in respect of any indebtedness, unless junior to this Note
in all respects, except for indebtedness of Maker outstanding as of the issuance
date of this Note. Maker agrees that neither Maker nor any direct or indirect
subsidiary of Maker will permit any liens, claims, or encumbrances to exist
against Maker or any direct or indirect subsidiary of Maker or any of their
assets, except for (i) indebtedness of Maker outstanding as of the issuance date
of this Note, and (ii) Permitted Indebtedness. "Permitted Indebtedness" means
indebtedness secured by the assets of Maker or any of its subsidiaries other
than the Collateral (as defined in the Security Agreement) so long as such
indebtedness does not exceed the value of the assets securing such indebtedness.
Maker may, at its sole discretion and without any required consent of Payee,
incur Permitted Indebtedness.

        5. Interest Withholding. If required by law, Maker shall withhold U.S.
tax under Sections 1441 or 1442, as the case may be of the Internal Revenue Code
of 1986, as amended (the "Code"), from all interest payments at the rate of
thirty percent (30%) unless Payee provides Maker three (3) duly executed copies
of Form 1001, prior to the Maturity Date or earlier Conversion Date, in which
case Maker shall withhold tax at the reduced rate specified in the Form 1001.
Maker shall provide Payee, on a timely basis, with a copy of Form 1042
evidencing the withholding of the tax under Sections 1441 or 1442, of the code,
as the case may be.

        6. In the event that Payee shall elect to convert any portion of this
Note as provided herein, Maker cannot refuse conversion based on any claim that
Payee or anyone associated or affiliated with Payee has been engaged in any
violation of law, unless an injunction from a court, restraining and/or
enjoining conversion of all or part of said portion of this Note shall have been


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                                                                  CPR (USA) INC.

issued and Maker posts a surety bond for the benefit of Payee in the amount of
130% of the New Principal sought to be converted plus outstanding interest
through such date, which is subject to the injunction, which bond shall remain
in effect until the completion of arbitration/litigation of the dispute and the
proceeds of which shall be payable to Payee in the event it obtains a favorable
judgment (but shall not in any way limit any additional damages Payee may be
entitled to).

        7. The following shall constitute an "Event of Default" :

               (a) Any of the representations, covenants, or warranties made by
Maker herein, or in the Agreement Regarding Indebtedness, Registration Rights
Agreement, and/or Security Agreement of even date herewith (collectively
referred to as the "Transaction Documents") shall have been incorrect when made
in any material respect or shall thereafter be determined to be incorrect; or

               (b) Maker shall breach, fail to perform, or fail to observe in
any material respect any material covenant, term, provision, condition,
agreement or obligation of Maker under this Note and/or the Transaction
Documents; or

               (c) A trustee, liquidator or receiver shall be appointed for
Maker or for a substantial part of its property or business without its consent
and shall not be discharged within thirty (30) calendar days after such
appointment; or

               (d) Any governmental agency or any court of competent
jurisdiction at the instance of any governmental agency shall assume custody or
control of the whole or any substantial portion of the properties or assets of
Maker and shall not be dismissed within thirty (30) calendar days thereafter; or

               (e) Bankruptcy reorganization, insolvency or liquidation
proceedings or other proceedings for relief under any bankruptcy law or any law
for the relief of debtors shall be instituted by or against Maker and, if
instituted against Maker, Maker shall by any action or answer approve of,
consent to or acquiesce in any such proceedings or admit the material
allegations of, or default in answering a petition filed in any such proceeding
or such proceedings shall not be dismissed within thirty (30) calendar days
thereafter; or

               (f) The Common Stock is suspended and/or delisted from trading on
the OTC Bulletin Board, or Maker has received notice of final action concerning
delisting from the OTC Bulletin Board; or

               (g) The effectiveness of the Registration Statement including the
shares of Common Stock underlying this Note has been suspended for a period of
five (5) business days; or

               (h) Maker shall fail to pay interest and/or principal within two
business days of when due hereunder; or

               (i) Maker shall have failed to deliver shares of Common Stock
issuable upon conversion of this Note pursuant to Section 3(c) above; or


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                                                                  CPR (USA) INC.

               (j) The occurrence of an Event of Default as that term is defined
in the Security Agreement; or

               (k) Maker, or any other party, shall, at any time after the
issuance date of this Note, (1) in any way adversely alter Payee's security
interest that it has been granted in the Collateral pursuant to the Security
Agreement, or (2) sell the Collateral in violation of the Security Agreement.

        8. Remedies. Upon the occurrence of an Event of Default, and in each and
every such case, unless such Event of Default shall have been waived in writing
by Payee (which waiver shall not be deemed to be a waiver of any subsequent
default) or cured as provided herein, at the option of Payee, and in Payee's
sole discretion, Payee may consider this Note (and all interest through such
date) immediately due and payable in cash (and enforce its rights under the
Security Agreement), without presentment, demand protest or notice of any kind,
all of which are hereby expressly waived, anything herein or in any note or
other instruments contained to the contrary notwithstanding, and Payee may
immediately, and without expiration of any period of grace, enforce any and all
of Payee's rights and remedies provided herein or any other rights or remedies
afforded by law (including but not limited to consequential damages if any). It
is agreed that in the event of such action, Payee shall be entitled to receive
all reasonable fees, costs and expenses incurred, including without limitation
such reasonable fees and expenses of attorneys. Nothing contained herein shall
limit the rights of Payee to collect liquidated damages as provided herein or in
any other agreement entered into between Maker and Payee, or any other damages
that Payee may otherwise be entitled to. Payee may declare all outstanding New
Principal, and all interest accrued thereon, immediately due and payable. The
rights and remedies available to Payee under this Note shall be cumulative and
in addition to any other rights or remedies that Payee may be entitled to pursue
at law or in equity. The exercise of one or more of such rights or remedies
shall not impair Payee's right to exercise any other right or remedy at law or
in equity. Notwithstanding the occurrence of a Default and/or Payee's exercise
of any of its rights or remedies hereunder, until such time as Payee receives
payment in full of all amounts due hereunder or shares of Common Stock pursuant
to an exercised Conversion Option, interest will continue to accrue on the
outstanding New Principal at the interest rate charged hereunder.

        9. Costs. Maker shall pay, on demand, any and all costs and expenses,
including reasonable attorneys' fees, incurred by Payee in connection with a
Default and the collection of any portion of the outstanding New Principal and
interest accrued thereon.

        10. No Offset. The amounts due under this Note are not subject to
reduction or offset for any claims of Maker or its successors or assigns against
Payee or any third party.

        11. No Continuing Waiver. The waiver of a Default shall not constitute a
continuing waiver or a waiver of any subsequent Default. Maker hereby waives
presentment, demand, dishonor and notice of nonpayment.

        12. Notice. Except as provided above, all notices, requests, consents
and other communications which may be desired or required hereunder shall be in
writing, and shall be deemed to have been duly given on the date of delivery if
delivered in person to the party named


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                                                                  CPR (USA) INC.

below, or three (3) business days after mailing if deposited in the United
States mail, first class, registered or certified mail, return receipt
requested, with postage prepaid, addressed as follows:

               If to Maker:         Spatializer Audio Laboratories, Inc.
                                    20700 Ventura Boulevard, Suite 140
                                    Woodland Hills, CA  91364
                                    Telephone:     (818) 227-3370
                                    Telecopier:    (818) 227-9751
                                    Attention:     Henry R. Mandell

               If to Payee:         c/o LibertyView Capital Management, Inc.
                                    101 Hudson Street, Suite 3700
                                    Jersey City, NJ  07302
                                    Telephone:     (201) 200-1199
                                    Telecopier:    (201) 200-1982
                                    Attention:     Alan Mark

or to such other persons or addresses as either party may from time to time
designate by notice given to the other party in accordance with this Section 11.
All payments made by Maker hereunder shall be made to Payee at the address set
forth above or as otherwise designated by Payee in accordance with this Section
12.

        13. Severability. If any provision of this Note or the application
thereof to any person or circumstance shall be held invalid or unenforceable to
any extent, the remainder of this Note and the application of any such provision
to other persons or circumstances shall not be affected thereby and shall be
enforced to the greatest extent permitted by law.

        14. Supercedes Prior Indebtedness. This Note, and the indebtedness
evidenced hereby, completely replaces, supercedes and extinguishes all
outstanding principal and accrued interest existing on or prior to the date
hereof (the "Prior Indebtedness") owed by Maker to Payee and/or to any person or
entity related to or affiliated with any Payee (each a "Related Party"). This
Note and that certain Agreement Regarding Indebtedness, dated of even date
herewith, by and among Maker and Payee, together constitute the entire
understanding of Maker, Payee and all Related Parties with respect to any
indebtedness of Maker to Payee or to any other Related Party, and completely
replace and supercede and all prior notes, letters, communications,
understandings, certificates, instruments, documents, and agreements, both oral
and written, that evidence or relate to any portion of the Prior Indebtedness,
including without limitation: (i) that certain letter agreement by and among
Maker and Payee, dated April 14, 1999; (ii) that certain letter agreement by and
among Maker and Payee, dated April 16, 1999; and (iii) that certain
Nonnegotiable Secured Promissory Note, dated on or about March 1999, made by
Maker in favor of Payee.

        15. Governing Law. This Note shall be exclusively construed and enforced
in accordance with and governed by the laws of the State of New York except for
matters arising under the Act, without reference to principles of conflicts of
law. Each of the parties consents to the exclusive jurisdiction of the federal
court, eastern district of the State of New York in connection with any dispute
arising under this Agreement and hereby waives, to the maximum extent permitted


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                                                                  CPR (USA) INC.

by law, any objection, including any objection based on forum non conveniens, to
the bringing of any such proceeding in such jurisdictions. Each party hereby
agrees that if another party to this Agreement obtains a judgment against it in
such a proceeding, the party which obtained such judgment may enforce same by
summary judgment in the courts of any state or country having jurisdiction over
the party against whom such judgment was obtained, and each party hereby waives
any defenses available to it under local law and agrees to the enforcement of
such a judgment. Each party to this Agreement irrevocably consents to the
service of process in any such proceeding by the mailing of copies thereof by
registered or certified mail, postage prepaid, to such party at its address set
forth herein. Nothing herein shall affect the right of any party to serve
process in any other manner permitted by law.

                  [Remainder of Page Intentionally Left Blank]


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                                                                  CPR (USA) INC.

        IN WITNESS WHEREOF, Maker has caused this Note to be executed and
delivered on the date first above written.



                              SPATIALIZER AUDIO LABORATORIES, INC., a Delaware
                              corporation



                              By:  /S/  Henry r. Mandell
                                   ---------------------
                              Name:  Henry R. Mandell
                                     ----------------
                              Title: Interim Chief Executive Officer
                                     -------------------------------


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