If you're heading down to Bloc on Bath Street, remember to park your cynicism at the door.

Free entry to gigs has been standard for years here, but now their Bloc+Music label is offering free downloads too: five various-artist compilations, released a fortnight or so apart, spanning the full width of Scotland's grassroots DIY scene, available at the click of a mouse from Bloc's site at bandcamp.com.

The first album, titled Bloc+ Ensemble Vol 2 Part 1 (it follows a 25-track venture tested out by Bloc last year), came out in late September. Including the likes of Adam Stafford, Deathcats, Verse Metrics and Chris Devotion And The Expectations, it was reviewed on these very pages: "Delete U2 and fit this on a playlist instead" was our advice.

Vol 2 Part 2 will be released next week, and takes a turn into a noisier neighbourhood inhabited by punk, hardcore, grunge and math rock, featuring Algernon Doll, So Many Animal Calls, Felix Champion and others. Already the series is forming quite a substantial snapshot of Scotland's proverbial ones-to-watch, and there's more to come.

"Originally we were only going to do four compilations, but we're doing five now, because of the interest that was shown in it," explains Bloc's booker and events manager Chris Cusack. "The additional album teams up with one of the live nights we have here, TYCI, a fanzine/organisation/blog by women for women about issues affecting women. We also use it as a platform to promote women's interests and involvement in the music scene, because there's a horribly low ratio of women to men in music. The track list for this compilation at the moment includes TeenCanteen, Sharp Tooth, Irenie Rosie and Skinny Dipper."

The TYCI compilation is scheduled for number four in the series. Before that comes one showcasing the lo-fi and artrock scene ("really inventive music that is highly unlikely to break through to any mainstream success … it's just a bit more off-the-wall and might confuse a few people") and a final release featuring, like the series opener, a more mixed line-up. According to Cusack, the curation of the bands on the compilations has grown naturally from Bloc's live music policy.

"We try to be as inclusive as possible, to try to cross-pollinate the scene," he insists, "bringing people from punk bands and hardcore bands into contact with people from folk bands and indie bands and post-rock bands … I don't think there's a band on any of these compilations that hasn't played here at least once."

It's all part of an "ethical" ideal that Bloc, under owner John Burns, has adhered to for a few years now. This might see the venue hire out its van at cost price to up-and-coming bands putting together an otherwise financially prohibitive first tour, or it might see the Bloc+Music label facilitate a "self-release" by securing a solid not-for-profit bulk deal for CDs at a pressing plant. In return, costs can be set against a handful of support slots the band might play in Bloc across a calendar year.

"It's not altruistic," Cusack admits of this and the compilation project, which has been timed to coincide with the relaunch of Bloc (and the introduction of a new food menu) after a short period of refurbishment. "It's publicity for the bar as well. But it also gives publicity to these bands and gets them mentioned in publications that maybe they otherwise wouldn't be in, on the back of what we think are good-quality songs. There are bound to be some people who are suspicious of our motives but I would suggest there is a genuine sense of … benevolence in that respect.

"The van has generated a loss overall for us, but it's won a lot of loyalty from the people who use it and it has generated the capacity for them to make money. It's about investing in these people and allowing them to tour at a sustainable level rather than coming back from a tour in debt."

Cusack reckons that such goodwill isn't forgotten when a band moves up a level. He points to Scottish indie-rock trio PAWS, who have hired that tour van in the past and who persuaded We Are Scientists to play with them at a now legendary freebie gig at Bloc in July "as a thank you".

"We want to lead by example and show that this model can work," Cusack says, "to show that by investing in your community, not just profiting from it, but progressing as part of it, people will reward you with loyalty. Ultimately, if we stopped the gigs tomorrow, this place would sell beer regardless. But being able to contribute to the community this way is much more fulfilling."

Bloc+ Ensemble Vol 2 Part 2 will be available at bloc.bandcamp.com from Wednesday. For details of Bloc's live events and bar menu, see bloc.ru