ResonantLive Sound Archive

Equipment file · Twin-driver front-loaded bass horn

4550 bass horn

JBL · 1971

Evidence status · documented

Identity and core specifications are documented; some historical fields remain unavailable.

The JBL 4550 is a front-loaded horn enclosure for two 15-inch drivers, used below 800 Hz; its sealed rear chamber extends response to about 50 Hz. The later 4550BKA was rated for both installation and portable use.

Introduced
1971
Category
Twin-driver front-loaded bass horn
Intended use
Low frequencies for larger theatre and PA systems
Production
JBL from 1971; later 4550BKA

Why it mattered

  1. 01

    A higher-power counterpart to the 4560 for arena and theatre bass.

  2. 02

    A standard building block in JBL's modular systems of the 1970s and 80s.

Engineering record

Drivers
Two 15-inch drivers, horn-loaded below 800 Hz[1]
Extension
Usable to about 50 Hz[1]

Original pricing

No reliable period price located

2026 equivalent

Not calculated without a reliable original price.

Public price evidence was not sufficient to publish a defensible original figure.

Use in the field

No named deployment could be tied to this exact item by a checked source yet. Know of one? Suggest it on the contribute page.

Manuals & original documents

Sources

  1. 1JBL 4550 Specificationsaudio-database.com · reference
  2. 24507, 4508, 4518, 4550BKA, 4560BKA Low Frequency EnclosuresJBL Professional · brochure

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