Spectrum were by far Australia's best known prog band of the 70s. The funny thing is that, just like the Madder Lake, Spectrum weren't all that prog, at least not by hardcore British prog standards of the day. In Spectrum's case, especially with their debut album, the effect often appears to be a splicing of generic soft rock and country rock with prog, a splicing which is often artificial and a far cry from better prog music that was available at the time. It should be pointed out that Spectrum were actually a pretty good straightahead rock band as evidenced with the success of the countryish rock of the classic single 'I'll Be Gone' and the band's alter ego Indelible Murtceps. This does lend more weight to the impression that the progressive approach is forced and artificial.To be fair though, Spectrum would improve the prog aspect of their sound and would become a more "authentic" prog band with the release of Milesago.
To be completely fair Part One is a promising debut and it would be unfair to expect Spectrum to deliver a completely rounded prog monster at the first attempt. And they did improve immediately with the following Milesago. But the weaknesses of Part One, which would be repeated, perhaps to a lesser extent, on Milesago, demonstrate why Spectrum aren't that well known apart from mostly hardcore prog aficionados and fans of 70s Australian rock.