Software dbx-I Compatible Compander

  DxI Codec is a modern digital equivalent of the traditional dbx-I noise reduction system for RtR (reel-to-reel) analog audio tape. The software is capable of decoding/encoding dbx-I formatted audio in digital domain without needing a dedicated analog hardware decoder/encoder. Benefiting from the proprietary DSP engine and the concise GUI, the task can be accomplished in realtime with intuitive user interaction, or more swifty with the batch processor.
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The software is able to adapt to different tape EQ standards. The built-in dedicated converter can easily translate audio material between CCIR/IEC1 and NAB/IEC2 specifications at different tape speeds. Aided by this converter, EQ mismatch is no longer a problem. It also allows a single-standard RtR machine being virtually used as a dual-standard one.

Dynamic range (DR) mismatch is another caveat in using high-ratio companders like dbx NR, which includes potential DR underload in compressing process and the potential DR overload in expanding process. The concern is addressed by the app with a novel dual-meter display that visualizes the potential DR mismatch, along with a threshold slider for instant correction.

As a new digital re-implementation of dbx-I NR, the software allows the traditional dbx NR encoding/decoding tasks to be done in digital domain and able to benefit from the gifted digital advantages, such as: zero new noise, mathematical accuracy, maintenance-free and very low cost. The digital codec's tracking speed is also adjustable for some special needs, such as decoding an audio material that was pre-encoded by a drifted hardware dbx encoder. However, the software is not made as an upgrade of the original analog dbx-I system´╝îinstead´╝îbeing as closer as it is. The digital engine is designed with full respect to the original analog system's topology with the same 2:1 pre-emphasized compression and the same 1:2 de-emphasized expansion which are controlled by the true RMS level detector with the same capacitive timing characteristics, even not attempted to "fix" the inherent side-effects such as "breathing" and intermodulation. It is just a new digital alternative that can accomplish the same traditional work with modern technology, without unnecessary improvements or compromises. For those who are transferring audio contents across the analog(A)/digital(D) border, the software is suitable for digitizing legacy tapes (A2D) or recording new tapes from bitstream (D2A). In case a dbx-I analog hardware unit is temporarily unacquirable or degraded, the software can serve as a similar role if double D/A A/D conversions are acceptable. And finally in dealing with pure digital archives (D2D), the software will make impossible possible.

DxI Codec is a stand-alone GUI app without relying on any other DAW host. It allows the computer to serve as an external(outboard) dbx-I/Disc compatible unit in one of the following four modes:

Input Output Comment
Audio In File a digitizer/recorder, with dbx-I/Disc codec
File Audio Out an audio file player, with dbx-I/Disc codec
File File an off-line dbx-I/Disc processor, with batch capability
Audio In Audio Out an on-line dbx-I/Disc processor, with slight delay

Currently supported audio file formats are:
WAV, FLAC, AIFF: up to 96k/24bit.
MP3, AAC, M4A: up to 48k/VBR.
* Excluding some proprietary variants having the common file extensions, or additional format-normalization may be required.

The software comes with embedded user manual on each major functions.

A VST plugin is also available as an optional software component of the application. However, it is currently in experimantal stage and requires the full application being installed on the same computer.

Please note that this software is suited for the Pro grade dbx type-I on reel-to-reel tape, which is not compatible with the consumer grade dbx type-II on cassette tape. However, it does come with an additional dbx type-Disc codec, which is suited for LP records.

Minimum System Requirements:
Mac: macOS 10.10 (Yosemte) or later
PC:  Windows 10 v1703 (build 15063) or later

How to Install:
The software is being distributed via App Store or Microsoft Store.
The best way to download and install the app is to use the OS built-in "Store" app (such as "App Store" on macOS or "Microsoft Store" on Windows 10+). A registered user account with Apple or Microsoft will be required to start. Although a transaction can be finished outside of the Store, e.g.: via a Web browser, the actuall download/install should be completed by using the OS built-in "Store" app. So, it is recommanded to do all the procedures by using the "Store" app.

  Audio Demo #1 (Piano)
Audio Demo #2 (Vocal)
Audio Demo #3 (Drums & Beats)
  Audio Demo #1 (Piano)
Audio Demo #2 (Vocal)
Audio Demo #3 (Drums & Beats)


dbx-I and dbx-Disc are the tape noise reduction systems developed by dbx Inc..

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Frequently Asked Questions (FAQ) Contact:



See also:
DDi Codec (for Dolby-B/C)
DxII Codec (for dbx-II/Disc)
NAK T-100 (Audio Analyzer)