Группа Spectrum была сформирована в 1969-ом году в Мельбурне.

7"
I'll Be Gone / Launching Place Part 2 (Harvest) 1971
Trust Me / Going Home (Harvest) 1971
But That's Alright / Play A Song That I Know (Harvest) 1971
Esmeralda / We Are Indelible (Harvest) 1972 (as The Indelible Murtceps)
Indelible Shuffle / Ray's Boogie (EMI) 1973 (as The Indelible Murtceps)

LP
1. SPECTRUM PART 1 (Harvest) 1971
2. MILESAGO (dbl) (Harvest) 1971
3. WARTS UP YOUR NOSE (HMV) 1973 (as The Indelible Murtceps)
4. TESTIMONIAL (dbl) (EMI) 1973 (Spectrum / Indelible Murtceps)