Introduced in 1978, the dbx® 1BX was designed to enhance the listening experience by increasing the dynamic range of audio playback. As a single-band expander, it aimed to make quiet sounds quieter and loud sounds louder, thereby restoring the natural dynamics often lost in recording and broadcasting processes.

With an expansion ratio adjustable up to 1.5:1, the 1BX could deliver up to a 50% improvement in stereo dynamic range across a wide frequency spectrum. This capability made it a valuable tool for audiophiles and professionals seeking to revitalize compressed audio sources like vinyl records, cassette tapes, and FM broadcasts.

The success of the 1BX led to subsequent models, including the 1BX Series II and 1BX Series III, which introduced additional features and refinements. These units remained popular among enthusiasts for their ability to breathe new life into vintage audio recordings.

Type X works by applying wideband dynamic expansion, a process that increases the difference between quiet and loud parts of a signal. Instead of compressing like a traditional compressor, it does the opposite: quiet sounds get quieter, and loud sounds stay loud (or even get slightly louder), making the music feel more dynamic and expressive.

Internally, Type X analyzes the input signal using a true RMS detector, just like the original hardware, to track its average energy over time. When the signal crosses a user-defined transition level, the expander applies gain changes based on the expansion ratio, with adjustable attack and release to shape how quickly it responds.

Type X also includes a filtered sidechain that lets you shape exactly what content triggers the expansion.

You can choose between the main input and an external sidechain signal as the source, then sculpt it with dedicated high-pass and low-pass filters. Use the Gain control to adjust the sidechain level independently, ensuring consistent triggering even with quiet or loud material.

You can also enable source listening to hear exactly what audio is being used by the expander.