I can’t find out much about the Specktrum. The band may have been from Cranston, Rhode Island but I’ve also seen them listed as from Abington, Massachusetts, which is south of Boston and an hour away from Cranston.
In February, 1967 they put out a single on Somethin’ Groovy Records SG-500 featuring two originals by the band, “Confetti” by R. Moore, K. Jeremiah and “I Was A Fool” by R. Schmeisser, K. Jeremiah. Publishing was through Exciting Music BMI but I can’t find anything in BMI’s database on these two songs or the writers.