***Edited - I listened to GM’s initial answer on my way to work this morning. Only now after posting this am I finishing the call where he makes some of these references*** 🥴
Regarding Karnamrita Das question yesterday on the Swami call about types of japa;
As we are accustomed Guru Maharaj gave the essential answer - what works for you is best, and is "recommended."
I went on a search for the mentioned references we're familiar with and found that the 3 types of chanting are mentioned in Hari Bhakti Vilasa. Still working on clarifying comments from Dig Darsini commentary of Sanatana Goswami:
TRIVIDHO JAPA YAJNAH SYAT TASYA BHEDAN NIVODHATA VACIKAS CA UPANSUS CA MANASAS CA TRIDHA MATAH TRAYANAM JAPA YAJNANAM SREYAN SYAD UTTAROTTARAH
(HARI BHAKTI VILASA 17/155 from NRSINGHA PURANA)
Japa yajna is of three kinds. Please listen. Chanting with a sound vibration, chanting with a murmuring condition and chanting within the mind. These three kinds of chanting are respectively one better than the other [chanting in the mind is best].
YADUCCHA NICA SVARITAIH SPASTA SAVDAVD AKSARAIH MANTRAM UCCHARAYED VYAKTAM JAPA YAJNA SA VACIKAH SANAIR UCCHARAYEN MANTRAM ISAD OSTHAU PRACALAYET KINCIT SAVDAM SVAYAM VIDYAD UPANSUH SA JAPAH SMRTAH
(HARI BHAKTI VILASA 17/156,157 from NRSINGHA PURANA)
Chanting japa is of three kinds, higher class, lower class and svarita class which is melodiously chanting clearly where every word can be heard by others. That is called vacika. Any japa mantra chanted in murmuring sound, where ones's two lips move very minutely and one can only hear a few words out of it, that chanting is called upansu.
Srila Sanatana Gosvami in his Digdarsini-tika writes that one who is chanting japa melodiously, with high and low sounds, in a swinging condition, it is called svarita where others can hear every sound vibration clearly. Therefore, it is said that one should chant openly. But better is to chant japa in such a way that one can hear it himself only.
UPANSU JAPA YUKTASYA TASMAT SATA GUNO BHAVET SAHASRO MANASAH PROKTO YASMAD DHYANA SAMO HI SAH
(HARI BHAKTI VILASA 17/159 from YAJNAVALKYA SMRTI)
One hundred times better than chanting japa in clear or loud condition is to chant japa in mumuring condition where one can hear himself. One thousand times better, still, is chanting within one's mind, because chanting within the mind is equal to meditating on the Supreme Lord.
Srila Sanatana Gosvami clarifies this situation in his Digdarsini-tika, stating that chanting within the mind is one hundred times better than chanting in murmuring condition which is one hundred times better than chanting with the sound vibration.
NADOSO MANASE JAPE SARVA DESE'PI SARVADA JAPA NISTHO DVIJA SRESTHAH SARVA YAJNA PHALAM LABHET ASUCIR VA SUCIR VAPI GACCHAN TISTHAN SVAPANNAPI MANTRAIVA SARANO VIDVAN MANASAIVA SADA ABHYASET
(HARI BHAKTI VILASA 17/161,162 from MANTRARNAVA)
Oh best of the brahmanas, in all conditions and always one should chant japa in one's mind because it has no faults. Therefore, anyone who is engaged in chanting japa, gets the results of performing all kinds of sacrifices. Whatever condition he may be, whether purified or unpurified condition, walking condition or still (standing or sitting) condition, sleeping condition, one should take shelter at the feet of chanting japa alone and chant japa within one's mind.
Srila Sanatana Gosvami remarks regarding chanting japa within one's mind, that because chanting japa within mind has no faults, therefore one should chant japa within one's mind. This is the best japa of all. Here "the best of brahmanas" refers to those who chant japa. In all conditions, one should take shelter in chanting japa without considering the time, place and circumstances. This is the understanding here.
Regarding the idea that Namacarya Haridasa Thakur chanted equally in these 3 ways there is a slightly related comment by BSST in CB commentary:
Chaitanya-bhagavata 1.16.172:
tabe haridasa ganga-tire gopha kari'
thakena virale ahar-nisa krishna smari'
"Then Haridasa went and found a cave on the bank of the Ganges. He remembered Krishna day and night as he resided alone in the cave."
Purport: "While remaining in a solitary cave on the bank of the Ganges at Phuliya, Srila Thakura Mahasaya loudly chanted the names of Krishna and passed his days and night remembering the pastimes of the Lord. Sometimes he would chant the sixteen name, thirty-two syllable, maha-mantra loudly (uccaihsvare), and sometimes he would chant softly (mrdusvare). Every day he would complete the chanting of three hundred thousand holy names, or in a year he would chant one hundred million names of Hari. Some people consider that chanting the names of Krishna in a solitary place is in the category of "upamsu-japa," or "chanting very mildly." They say that this maha-mantra, or chanting the holy names of the Lord, should not be heard by others; only the person who is chanting should hear. If the lips move, or if the holy names are recited, then they will automatically be heard by others. But if such persons lack faith in the Vaisnavas who chant the holy names of the Lord, then by the influence of Kali they dare to quarrel with those Vaisnava chanters."
The only specific reference I'm able to find to Haridas chanting in this way appears to come from "Advaita Prakash". The origins of the book are debated by some, but without getting into that (and without being able to read it myself) here is that reference: (7.152) prati-dina tin lakshaa haridasa kore,manane jihvaya ruccaih svare, “Every day Haridasa Thakura chanted three lacs (300,000 Holy Names) in the mind, with the tongue, and loudly.”
Good find!
I also came across this in Bhakti Sandarbha, which makes the same caveat that GM often does re. silent chanting: