You might be noticing the tunes he plays on a G box. He made a lot of early recordings on a G. Perhaps that may account for some of the difference you noticed. A "G" accordion is very low or full, if you will.

I agree on the "low" as sound for a G, but i play it a lot in a band situation, even more than my C or D, and then mostly for folk related stuff, not as much for Cajun, and a lot with the L stop closed. Never regretted buying this G, besides that i also like the sound without the L bank active for Cajun stuff at times .... Nout

His accordion was indeed built by John Roger. "Cajun" brand. I belive It is slightly wet tuned so the ringing sound you hear is due to that. John's shop was flooded by hurricane Katrina and he lost everything. He has relocated and is building again but to what extent I do not know. He posts here from time to time, hopefully he will chime in and clarify.