Document:

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                                                                 EXHIBIT 4.16.12

                  ELEVENTH SUPPLEMENTAL INDENTURE (this "Supplemental
Indenture"), dated as of May 18, 1998, among SFX BROADCASTING OF SOUTH CAROLINA,
INC., a Delaware corporation (the "Guarantor"), which is a subsidiary of SFX
Broadcasting, Inc., a Delaware corporation (the "Company"); and The Chase
Manhattan Bank, as trustee under the indenture referred to below (the
"Trustee").

                                   WITNESSETH

                  WHEREAS, The Company has heretofore executed and delivered to
the Trustee an indenture (the "Indenture"), dated as of May 31, 1996, providing
for the issuance of an aggregate principal amount of $450,000,000 of 10 3/4%
Senior Subordinated Notes due 2006 (the "Securities"); and

                  WHEREAS, Section 4.15 of the Indenture provides that under
certain circumstances the Company is required to cause the Guarantor to execute
and deliver to the Trustee a supplemental indenture pursuant to which such
Guarantor shall unconditionally guarantee all of the Company's obligations under
the Securities pursuant to a Subsidiary Guarantee on the terms and conditions
set forth herein;

                  NOW THEREFORE, in consideration of the foregoing and for other
good and valuable consideration, the receipt of which is hereby acknowledged,
the Guarantor and the Trustee mutually covenant and agree for the equal and
ratable benefit of the holders of the Securities as follows:

                  1. CAPITALIZED TERMS. Capitalized terms used herein without
definition shall have the meanings assigned to them in the Indenture.

                  2. AGREEMENT TO GUARANTEE. The Guarantor hereby agrees,
jointly and severally with all other guarantors, to guarantee the Company's
obligations under the Securities on the terms and subject to the conditions set
forth in Article 11 of the Indenture and to be bound by all other applicable
provisions of the Indenture, including, without limitation, the provisions of
Article 10 of the Indenture.

                  3. NO RECOURSE AGAINST OTHERS. No past, present or future
director, officer, employee, incorporator, shareholder or agent of the
Guarantor, as such, shall have any liability for any obligations of the Company
or the Guarantor under the Securities, the Subsidiary Guarantees, the Indenture
or this Supplemental Indenture or for any claim based on, in respect of, or by
reason of, such obligations or their creation. Each holder of the Securities by
accepting a Security waives and releases all such liability. The waiver and
release are part of the consideration for issuance of the Securities. Such
waiver may not be effective to waive liabilities under the federal securities
laws and it is the view of the Commission that such a waiver is against public
policy.

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                  4. EFFECTIVENESS. This Supplemental Indenture shall be
effective upon execution by the parties hereto.

                  5. RECITALS. The recitals contained herein shall be taken as
the statements of the Company and the Guarantor and the Trustee assumes no
responsibility for their correctness. The Trustee makes no representations as to
the validity of this Supplemental Indenture.

                  6. NEW YORK LAW TO GOVERN. THE INTERNAL LAW OF THE STATE OF
NEW YORK SHALL GOVERN AND BE USED TO CONSTRUE THIS SUPPLEMENTAL INDENTURE.

                  7. COUNTERPARTS. The parties may sign any number of copies of
this Supplemental Indenture. Each signed copy shall be an original, but all of
them together represent the same agreement.

                  8. EFFECT OF HEADINGS. The Section headings herein are for
convenience only and shall not affect the construction hereof.

                  IN WITNESS WHEREOF, the parties hereto have caused this
Supplemental Indenture to be duly executed as of the date first above written.

                                         THE CHASE MANHATTAN BANK,
                                          as Trustee

                                         By: /s/ Francine Springer
                                            ------------------------------------
                                            Name:  Francine Springer
                                            Title:  Assistant Vice President

                                         SFX BROADCASTING OF SOUTH CAROLINA,
                                         INC.

                                         By: /s/ Richard A. Liese
                                            ------------------------------------
                                            Name: Richard A. Liese
                                            Title:  Vice President

                                       -2-<PAGE>   1
                                                                 EXHIBIT 4.16.13

         TWELFTH SUPPLEMENTAL INDENTURE (this "Supplemental Indenture"), dated
as of May 29, 1998, among KJQY-FM Licensee, Inc., a Delaware corporation; SFX
Broadcasting of Texas (KTCK), Inc., a Delaware corporation; SFX Broadcasting of
Texas (KTCK), Licensee, Inc., a Delaware corporation; SFX Broadcasting of San
Diego, Inc., a Delaware corporation; Parker Broadcasting Company, a California
corporation; SFX Broadcasting of San Diego Licensee, Inc., a Delaware
corporation; Liberty Broadcasting, Incorporated, a Delaware corporation; Liberty
Broadcasting Group Incorporated, a Delaware corporation; Liberty Broadcasting of
New York Incorporated, a New York corporation; Liberty Broadcasting of Albany
Incorporated, a New York corporation; Liberty Broadcasting of Maryland II
Incorporated, a Maryland corporation; WHJJ, Inc., a Rhode Island corporation;
WHFM, Inc., a New York corporation; WHCN, Inc., a Connecticut corporation;
WHCN-FM, Inc., a Delaware corporation; WNSE, Inc., a Rhode Island corporation;
WSNE-FM, Inc., a Delaware corporation, WMXB, Inc., a Virginia corporation; WPYX,
Inc., a New York corporation; WHJY, Inc., a Rhode Island corporation; WPOP,
Inc., a Connecticut corporation; WGNA, Inc., a New York corporation; WGNA-FM,
Inc., a New York corporation; WGBB, Inc., a New York corporation; Beck-Ross
Communications, Inc., a Delaware corporation; WTRY, Inc., a New York
corporation; WYSR, Inc., a Connecticut corporation; WBLI, Inc., a New York
corporation; WBLI-FM, Inc., a Delaware corporation, WBAB, Inc., a New York
corporation; SFX Broadcasting of Hartford, Inc., a Delaware corporation;
Multi-Market Radio, Inc., a Delaware corporation; Southern Starr Broadcasting
Group, Inc., a Delaware corporation; Southern Starr of Arkansas, Inc., an
Arkansas corporation; General Communicorp, Inc., a Connecticut corporation;
General Broadcasting of Connecticut, Inc., a Connecticut corporation; Southern
Starr Communications, Inc., a Delaware corporation; Southern Starr Limited
Partnership, a partnership organized in Delaware; Multi-Market Radio of Augusta,
Inc., a Delaware corporation; Multi-Market Radio of Myrtle Beach, Inc., a
Delaware corporation; Multi-Market Radio of Northhampton, Inc., a Delaware
corporation; Multi-Market Radio of Hartford, Inc., a Delaware corporation;
Southern Starr Management, Inc., a Delaware corporation; General Broadcasting of
Florida, Inc., a Florida corporation; General Broadcasting Corp., a Connecticut
corporation; Great American Music Fest & Production Co., a Connecticut
corporation; Multi-Market Radio of Fayetteville, Inc., a Delaware corporation;
SFX Broadcasting of Arizona, Inc., a Delaware corporation; SFX Broadcasting of
California, Inc., a Delaware corporation; SFX Broadcasting of Connecticut, Inc.,
a Delaware corporation; SFX Broadcasting of Connecticut Licensee, Inc., a
Delaware corporation; SFX Broadcasting of Florida, Inc., a Delaware corporation;
SFX Broadcasting of Hartford II, Inc., a Delaware corporation; SFX Broadcasting
of Kansas, Inc., a Delaware corporation; SFX Broadcasting of Massachusetts,
Inc., a Delaware corporation; SFX Broadcasting of Massachusetts Licensee, Inc.,
a Delaware corporation; SFX Broadcasting of New York, Inc., a Delaware
corporation; SFX Broadcasting of Pennsylvania, Inc., a Delaware corporation; SFX
Broadcasting of Rhode Island, Inc., a Delaware corporation; SFX Broadcasting of
South Carolina, Inc., a Delaware Corporation; SFX Broadcasting of Virginia,
Inc., a Delaware corporation; SFX Broadcasting of Wisconsin, Inc., a Delaware
corporation; SFX GP, Inc., a Delaware corporation; SFX Holdings, Inc., a
Delaware corporation; SFX Operating Company of Mississippi, Inc., a Delaware
corporation; SFX Operating Company of North Carolina, Inc., a Delaware
corporation; SFX Operating Company of Tennessee, Inc., a Delaware corporation;
SFX Operating GP, Inc., a Delaware corporation; SFX Performance Marketing, Inc.,
a Delaware corporation; SFX Texas Limited Partnership, a partnership organized

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in Delaware; SFXAZ Limited Partnership, a partnership organized in Delaware;
SFXBX Limited Partnership, a partnership organized in Delaware; SFXFL Limited
Partnership, a partnership organized in Delaware; SFXIN Limited Partnership, a
partnership organized in Delaware; SFXKS Limited Partnership, a partnership
organized in Delaware; SFXMS Limited Partnership, a partnership organized in
Delaware; SFXNC Limited Partnership; a partnership organized in Delaware; SFXPA
Limited Partnership, a partnership organized in Delaware; SFXSC Limited
Partnership, a partnership organized in Delaware; SFXTN Limited Partnership, a
partnership organized in Delaware; SFXTX Limited Partnership, a partnership
organized in Delaware; SFXWI Limited Partnership, a partnership organized in
Delaware, WWYZ, Inc., a Connecticut corporation; ABS Communications, L.L.C., a
Virginia limited liability company; SFX Indiana Limited Partnership, a Delaware
limited partnership; SFX Radio Network of North Carolina, Inc., a Delaware
corporation; each a subsidiary of SFX Broadcasting, Inc., (the "Company"), a
Delaware corporation (each of the above entities other than the Company, a
"Guarantor"), and The Chase Manhattan Bank (formerly known as Chemical Bank), as
trustee under the indenture referred to below (the "Trustee").

                                   WITNESSETH:

         WHEREAS, the Company and the Guarantors have heretofore executed and
delivered to the Trustee an indenture, dated as of May 31, 1996, as amended by
supplemental indentures, dated as of November 25, 1996, January 10, 1997,
January 13, 1997, January 29, 1997, May 15, 1997, July 8, 1997, October 9, 1997,
October 10, 1997, January 23, 1998, February 2, 1998 and May 18, 1998
(collectively, the "Indenture"), providing for the issuance of an aggregate
principal amount of $450,000,000 of the Company's 10 3/4% Senior Subordinated
Notes due 2006 (the "Notes");

         WHEREAS, Section 5.01 of the Indenture provides that under certain
circumstances the Company is required to cause each Guarantor to execute and
deliver to the Trustee a supplemental indenture pursuant to which such Guarantor
shall confirm that its Subsidiary Guarantee shall apply to the Company or the
surviving Person's Obligations under the Indenture and the Notes in the event of
a merger, consolidation or sale, assignment, transfer lease, conveyance or other
disposition of all or substantially all of the Company's assets or properties
(the "Fundamental Change");

         WHEREAS, the Company is going to be the surviving Person pursuant to
the Agreement and Plan of Merger dated as of August 24, 1997, as amended, among
SBI Holdings Corporation, SBI Radio Acquisition Corporation and the Company;

         NOW THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt of which is hereby acknowledged, the
Guarantors and the Trustee mutually covenant and agree for the equal and ratable
benefit of the holders of the Securities as follows:

         NOW THEREFORE, in consideration of the foregoing and for other good and
valuable consideration, the receipt of which is hereby acknowledged, it is
hereby agreed as follows:

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1. CAPITALIZED TERMS. Capitalized terms used herein without definition shall
have the meanings assigned to them in the Indenture.

2. CONFIRMATION. Each Guarantor hereby confirms, pursuant to Section 5.01 of the
Indenture, that its Subsidiary Guarantee shall continue to apply to the
Company's Obligations under the Indenture and the Notes after the Fundamental
Change.

3. NO RECOURSE AGAINST OTHERS. No past, present or future director, officer,
employee, incorporator, shareholder or agent of the Guarantors, as such, shall
have any liability for any obligations of the Company or the Guarantors under
the Securities, the Subsidiary Guarantees, the Indenture or this Supplemental
Indenture or for any claim based on, in respect of, or by reason of, such
obligations or their creation. Each holder of the Securities by accepting a
Security waives and releases all such liability. The waiver and release are part
of the consideration for issuance of the Securities. Such waiver may not be
effective to waive liabilities under the federal securities laws and it is the
view of the Commission that such a waiver is against public policy.

4. EFFECTIVENESS. This Supplemental Indenture shall be effective upon execution
by the parties hereto.

5. RECITALS. The recitals contained herein shall be taken as the statements of
the Guarantors and the Trustee assumes no responsibility for their correctness.
The Trustee makes no representations as to the validity of this Supplemental
Indenture.

6. NEW YORK LAW TO GOVERN. The internal law of the State of New York shall
govern and be used to construe this Supplemental Indenture.

7. COUNTERPARTS. The parties may sign any number of copies of this Supplemental
Indenture. Each signed copy shall be an original, but all of them together
represent the same agreement.

8. EFFECT OF HEADINGS. The Section headings herein are for convenience only and
shall not affect the construction hereof.

                                       3
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         IN WITNESS WHEREOF, the parties hereto have executed this Twelfth
Supplemental Indenture as of the date first above written.

                                KJQY-FM Licensee, Inc.

                                SFX Broadcasting of Texas (KTCK) Licensee, Inc.

                                SFX Broadcasting of San Diego, Inc.

                                Parker Broadcasting Company

                                SFX Broadcasting of San Diego Licensee, Inc.

                                Liberty Broadcasting, Incorporated

                                Liberty Broadcasting Group Incorporated

                                Liberty Broadcasting of New York Incorporated

                                Liberty Broadcasting of Albany Incorporated

                                Liberty Broadcasting of Maryland II Incorporated

                                WHJJ, Inc.

                                WHFM, Inc.

                                General Broadcasting Corp.

                                Southern Starr Management, Inc.

                                General Broadcasting of Florida, Inc.

                                SFX Broadcasting of Texas (KTCK), Inc.

                                WHCN, Inc.

                                WHCN-FM, Inc.

                                WSNE, Inc.

                                WSNE-FM, Inc.

                                       4
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                                WMXB, Inc.

                                WPYX, Inc.

                                WHJY, Inc.

                                WPOP, Inc.

                                WGNA, Inc.

                                WGNA-FM, Inc.

                                WGBB, Inc.

                                Beck-Ross Communications, Inc.

                                WTRY, Inc.

                                WYSR, Inc.

                                WBLI, Inc.

                                WBLI-FM, Inc.

                                WBAB, Inc.

                                SFX Broadcasting of Hartford, Inc.

                                Multi-Market Radio, Inc.

                                Southern Starr Broadcasting Group, Inc.

                                Southern Starr of Arkansas, Inc.

                                General Communicorp, Inc.

                                General Broadcasting of Connecticut, Inc.

                                Southern Starr Communications, Inc.

                                Southern Starr Limited Partnership

                                Multi-Market Radio of Augusta, Inc.

                                       5
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                                Multi-Market Radio of Myrtle Beach, Inc.

                                Multi-Market Radio of Northampton, Inc.

                                Multi-Market Radio of Hartford, Inc.

                                SFX Broadcasting of Indiana, Inc.

                                Great American Music Fest & Production Co.

                                Multi-Market Radio of Fayetteville, Inc.

                                SFX Broadcasting of Arizona, Inc.

                                SFX Broadcasting of California, Inc.

                                SFX Broadcasting of Connecticut, Inc.

                                SFX Broadcasting of Connecticut Licensee, Inc.

                                SFX Broadcasting of Florida, Inc.

                                SFX Broadcasting of Hartford II, Inc.

                                SFX Broadcasting of Kansas, Inc.

                                SFX Broadcasting of Massachusetts, Inc.

                                SFX Broadcasting of Massachusetts Licensee, Inc.

                                SFX Broadcasting of New York, Inc.

                                SFX Broadcasting of Pennsylvania, Inc.

                                SFX Broadcasting of Rhode Island, Inc.

                                SFX Broadcasting of South Carolina, Inc.

                                SFX Broadcasting of Virginia, Inc.

                                SFX Broadcasting of Wisconsin, Inc.

                                SFX GP, Inc.

                                       6
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                                SFX Holdings, Inc.

                                SFX Operating Company of Mississippi, Inc.

                                SFX Operating Company of North Carolina, Inc.

                                SFX Operating Company of Tennessee, Inc.

                                SFX Operating GP, Inc.

                                SFX Performance Marketing, Inc.

                                SFX Texas Limited Partnership
                                By: SFX Operating GP, Inc., as General Partner

                                SFXAZ Limited Partnership
                                By: SFX GP, Inc., as General Partner

                                SFXBX Limited Partnership
                                By: SFX GP, Inc., as General Partner

                                SFXFL Limited Partnership
                                By: SFX GP, Inc., as General Partner

                                SFXIN Limited Partnership
                                By: SFX GP, Inc., as General Partner

                                SFXKS Limited Partnership
                                By: SFX GP, Inc., as General Partner

                                SFXMS Limited Partnership
                                By: SFX GP, Inc., as General Partner

                                SFXNC Limited Partnership
                                By: SFX GP, Inc., as General Partner

                                SFXPA Limited Partnership
                                By: SFX GP, Inc., as General Partner

                                SFXSC Limited Partnership
                                By: SFX GP, Inc., as General Partner

                                       7
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                                SFXTN Limited Partnership
                                By: SFX GP, Inc., as General Partner

                                SFXTX Limited Partnership
                                By: SFX GP, Inc., as General Partner

                                SFXWI Limited Partnership
                                By: SFX GP, Inc., as General Partner

                                WWYZ, Inc.

                                ABS Communications, L.L.C.
                                By: SFX Broadcasting, Inc., Authorized Member

                                SFX Indiana Limited Partnership
                                By: SFX Broadcasting of Indiana, Inc. as General
                                Partner

                                SFX Radio Network of North Carolina, Inc.

                                By:      /s/ William S. Banowsky, Jr.
                                         ---------------------------------------
                                         Name:  William S. Banowsky, Jr.
                                         Title:  Vice President

                                The Chase Manhattan Bank, as Trustee

                                By:      /s/ Francine Springer
                                         ---------------------------------------
                                         Name: Francine Springer
                                         Title:  Assistant Vice President

                                       8

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