Hari Bhakti Vilas on Chanting Japa

http://www.gopala.org/node/211
Sanätana Gosvämé writes in his commentary to Hari-bhakti Viläsa that

1. murmuring (upaàçu) is actual japa,
2. while loud japa equals kértana and
3. mental japa equals meditation.

Wherever there are statements, like in Caitanya Bhägavata, that loud chanting is better,
they are made in the context of preaching

Quote
http://namesmeditation.blogspot.in/2011/07/loud-japa-is-not-better-than-mental-jap.html