Scotland's Government offers Business Gateway that offers money for new businesses as well as advice.
Consider a local council as well because they may have other options available as they would like to promote local business and sometimes offer amounts of money.
Depending if your in the UK or not there may be something similar to the above in your area.
Make sure your market your service first as well and decide what you would like to provide entertainment for e.g weddings, birthday parties etc and find out how much your competitors would be charging for the same services.
The source below also offers some advice on starting a business.
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Ah I see, in that case it is a whole different kettle of fish, I don't imagine any grants being available for something like that then.
Have you considered working with any local music studios/theatres to try and get a sponshership or something like that?
Although I do see now it's really just an investor your interested in. Suppose the only other thing to look at is how to make a quick buck. Selling things on ebay, car washes.
For your recording equipment for music have you ever used Mixcraft? Its a pretty basic set up, but it does the job for a cheap solution, basic effects etc. You get like a 30 day free trial without entering any credit details. I use it every so often. At least with that you could maybe record a mini EP and sell that and try to make a bit of cash off that, if you promote it on your facebook twitter etc.Try get it on local radio. Bit of a long shot but if its something different it may help just to boost a little bit of funds and if anything keeps you busy whilst you save up your target.
Best of luck