what clarinet has the deeper tone: contra alto clarinet or bass clarinet?

gabs

Contra alto is lower then bass clarinet.

how much deeper? just by a few notes or noticably deeper? what is the order of clarinet tones?

In order from highest to lowest pitch. Most of these instruments are very uncommen but do exist.

Ab Sopranino (major 7th above Bb Soprano)
Eb Soprano (major 4th above Bb Sopeano)
D Soprano
C Soprano
Bb Soprano
A Soprano
Basset Horn in F
Eb Alto (major 4th below Bb Soprano)
Bb Bass (1 octave below Bb Soprano)
EEb Contra-Alto
BBb Contrabass (2 octaves below Bb Soprano)
EEEb Octo-Contra-Alto (only 3 built)
BBBb Octo-Contrabass (3 octaves below Bb Soprano - only 1 built)

There also is G- lower than the A clarinet which is still used in turkey, and they have the G clarinet an octave above that. There are records indicating an "octave C clarinet" or something like that (meaning an octave above reg. C clarinet) exist as a kind of piccolo instrument i guess, but few exist and very few people would be nimble enough to play them.

Bradley

question of "how much lower"...

when comparing an EEb contra with range to low Eb to a Bb bass clarinet with a typical range then the contra wins by a 4th or 5th (half an octave!)

but, few EEb contras come with an extended range to low C and many Bb bass clarinets do have a range to low C. In that case -- the two are almost equal in lower range but the bass has a higher range.

the BBb contra has a range one full octave lower than the Bb bass without C extension.

Differences to consider though -- the EEb has a different timbre (sound) than just a big bass clarinet. It`s very warm down there and not as woody as the bass. One advantage to the EEb is the ease of transposing tuba/trombone/euphonium/bassoon/cello parts compared to Bb bass.

Of course, anyone interested in seriously playing the big clarinets should learn to read in treble and bass fluently and to transpose at sight from Bb to Eb (or Eb to Bb) and C to Bb. (my opinion)