Isolating a large basement room

- I've inherited a large games room, which I'd like to be able to sound-proof enough that I can run my speakers (6" KRKs) at decent monitoring level without any disturbance to the neighbours (I don't pummel my ears, so monitoring at 80 - 90 dBSPL). They're about 30-40 feet away. Assume little/nil in the way of insulation, as is the norm in this country. I think the construction style is mainly thin gib boards on studs. The wall that sits hard against the ground (as in the picture) is made of blocks that look like concrete or big bricks. - I think the main weak point is the wall that seperates inside/outside. It has a thin window and old sliding door on it. The room is on the basement level, so there's the house above the ceiling, solid foundation (earth) against one wall, and the house "interior" (other rooms) against the 2 other walls. I would, however, like to hear about good overall plans for the space, not just solutions for that one wall I singled out, because I'm not entirely sure how much isolation the other walls can provide. - Room size is 7.8 metres long, 5 metres wide, 2.4 metres high. It's a nice basic plan, as shown in the pic. - I don't own this house - my dad does - and for obvious reasons he wants to keep some form of natural light and outside access door on that wall, so those aspects must remain or be incorporated in some shape or form. I know these will compromise isolation, but this is, as happens so often, just how it is. - If you need to have a budget to work in, start with say $4 grand US, (about 6 - 7 grand over here). But suggest anything if it will work well, and can decide later if I want to spend up.

Please read the forum RULES (stickies) that can be found at this link: viewforum.php?f=17 Then make certain that this is reviewed: viewtopic.php?f=2&t=3231 Please correct your initial post to conform with these rules and guidelines. Many here will not only NOT help while waiting in respect for owners and other better qualified persons to proceed, but will simply ignore these type of posts completely. You may want to immediately ask "what is it that I have missed". Most often it is as simple as including your geographical location in your profile. It might be that you have not included your budget! Trust me in that the more you know the better others can help you and that the answer to that question is in the forum rules linked page. Until then, good luck, Brien p.s. your room dimensions