My audiobook productions meet the following criteria and are compliant with ACX, Audible, Amazon and iTunes requirements.
- consistent in overall sound and formatting.
- free of extraneous sounds such as plosives, mic pops, mouse clicks, excessive mouth noise, and outtakes.
- include opening and closing credits that match the title’s cover art.
- include a retail audio sample that is between one and five minutes long.
- 0.5 to 1 second of room tone at its beginning and 1 to 5 seconds of room tone at its end.
- Total RMS level between -23dB and -18dB RMS.
My usual total RMS level is between -22.9dB and -22.7dB. This is at the lower end of ACX specification which is designed to give maximum clarity across all listening devices. Staying at the lower end gives a greater amount of dynamic range, whilst still remaining clear.
I normally leave around a 1 second gap at the start of a chapter and a 3 second gap at the end, adding up to a total of 4 seconds’ gap between chapters. All paragraph or similar breaks within the chapter are never more than 3 seconds to give the listener a consistent experience.
- peak values no higher than -3dB.
- noise floor no higher than -60dB RMS.
- 192kbps or higher 44.1kHz MP3, Constant Bit Rate (CBR).
I can also provide flac, WAV: 44.1/48/96 kHz, 16/24-bit and BWF (Broadcast Wave Format): 44.1/48/96 kHz, 16/24-bit
Over and above these specifications:
- my productions have no “boxy” or “echoing” room sound, since my recording space is acoustically treated.
- There is no distracting background noise such as hiss, computer fan noise, distant traffic, footsteps, creaks, crackles and rattles, etc.
- There is no audible noise reduction on my recordings (i.e when the background noise noticeably disappears at the end of each word) and natural breaths are not automatically removed.
- I pay close attention to frequency equalization, which I customise to each project, the end result being neither too bassy or “boomy” or thin and trebly.
- I test-listen my finished productions on a variety of devices, in addition to my reference-quality headphones and studio monitors, to ensure consistency, including: small laptop speakers, apple earbuds, mid-range hi-fi speakers and in-car speakers.