MicroMPX+: Lower bitrates
If even 320 kbit/s is too much for you, MicroMPX+ offers even lower bitrates, all the way down to 176 kbit/s.
Please be aware that, especially at the lowest bitrates, certain benefits of MicroMPX might not be fully available. MicroMPX was made specifically for FM, which means that if it cannot encode at full quality, it adds artifacts that sound like FM reception artifacts, instead of way more annoying MP3/AAC-like artifacts. At low bitrates, this can become audible. MicroMPX+ includes information about those codec artifacts so the decoder can filter them out. That works very well, but the filtering can slightly change the waveform (*, moreso if the bitrate is lower), due to which we cannot guarrantee that a fully ITU-R.1268 (AKA "Stokkemask") compliant signal will still be compliant on the other end. Most audio processors don't even offer this feature, but for example Stereo Tool and the Omnia.9 do. While even a 176 kbit/s encoded Stereo Tool signal with ITU-R.1268 enabled will still be much closer to ITU-R.1268 than a signal without this. As far as we are aware, compliance to this standard is only mandatory in the Netherlands and Belgium.
(*) Changing the waveform can also cause small overshoots, but it's typically only a single sample that's too high, and we compensate for that using a very simple clipper - the effect isn't audible and because it only affects a few 1-sample spikes it doesn't affect loudness.