If you’re just starting out, you may be wondering how we decide to approve your 1-minute test. Here’s a description of my routine to explain those pesky “technical specifications,” and provide some useful tips and tools.
Please check your specs before uploading. This post is not designed to let you to skip approval by a seasoned reader, but may cut down on server space and workload for the volunteers approving tests.
Always wait for an [OK] on your test from an admin/seasoned volunteer before embarking on your recording journey.
My routine for checking 1-minute tests
1. Copy the url of the uploaded test.
2. Open the free downloadable tool Checker, go to “Files > Check Urls” and paste in the url to check the file’s technical specifications. The Checker will measure bit rate, volume, DC bias (offset), clipped audio, and background noise. (If you’re checking your own files, you’d use “Files > Check Files” instead, or just drag your file into the upper box.)
3. Play file and listen for any background noise, plosives, clicks, etc. The standard text provided here under “Ready to Record?” is useful because it contains some of the sounds that commonly cause issues (e.g., plosives or pops). Sometimes I’ll download the file and look at it in Audacity to see if I can figure out what is causing a particular click or background noise.
4. Check my files to see if I have standard wording to address any issues I see/hear.
5. Post reply, either approving the test or providing suggestions/instructions on how to fix issues.
6. If the test isn’t approved in the first round, come back when it’s re-uploaded to check again. Repeat as necessary.
7. Within a day or two after I’ve approved a test, one of the admins reviews my response and adds the [OK] to the subject line. (Only the admins can add that to the subject line.)
When I approve a test, I also provide links to other forums where you can find a first piece to record or ask for help.
Librivox Wiki pages that provide useful information
- Clipped audio (Note: outdated page only useful for its description of clipping.)
Helpful free downloadable tools/plugins
- Checker to check volume, DC bias, bit rate, background noise, and other technical specifications.
To get it to show background noise, select “Validation > Choose Validation Methods,” and tick the box for “Background Noise.” You only need to do this once. The Checker reviews the last 5 seconds of silence in a recording to assess background noise (all Librivox recordings are required to have 5 seconds of silence at the end so they work properly in all media players).
- In Audacity, the free downloadable plugin ReplayGain to measure volume, and find out exactly how far it is from 89 dB.
If the ReplayGain level is at or near 0, your volume is very close to 89 dB. If it’s between +3 and -3, you're within the acceptable range for LibriVox (ideally 89 – 90 dB, but anything between 86 and 92 dB is acceptable).
This plugin does not change your volume; it only measures it. If volume needs to be raised or lowered, use either “Effect > Loudness Normalization,” set to -19LUFS and “perceived loudness,” or “Effect > Amplify” and put an amount into the “Amplification (dB)” box to bring it to the right level (remember, you’re aiming for 0). So if, for example, your volume is at 93 dB, you’d have to enter -4 to bring it down to 89. If it’s 85 dB, you’d have to enter 4 to bring it up to 89 dB.
Still got questions? Not an Audacity user? Head over to the "Need Help? Got Advice?” forum and post your question there to get answers from other readers.