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I have a very good stereo setup (K&H 0300) and another pair of decent speakers (Event TR6) sitting around.
I would love to keep using those speakers and combine them to a Frankenstein Surround system.
Will i have something that i can get away with for premixing / sound designing in surround?
How would i calibrate this setup, since the speakers will have different specs...
My sub is a 200$ and i would use a third speaker from another manufacturer for the centre.
Reading this now, it looks pretty hopeless, and i suppose i will just have have to wait until i have the cash to do an all K&H thing... but their sub alone cost 1.5K $....and i would need 3x 2K $ speakers for rears and center - ouch.
What do the experts say? Is there a way to turn my frankenstein into something usable?
Again: premix only...
There is a big difference between the two tasks you mention ie sound editing/design vs remixing - the former you will be premixing in another (calibrated) studio, the latter requires a well configured, spec'd and aligned mix room.
So for sound editing, go for it! But read up on speaker line up on the DUC thread - get an SPL meter & line up your speakers so that while they may not be perfectly matched, they will still be level balanced (& definitely better than eg no surrounds!)
But for premixing? Personally I would not want to be making critical balance decisions in a room without it being fully specc'd....
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It will be usable but not very accurate, it is not just EQ but also ballistics, the different brands will have slight timing differences across the frequency range.
I agree with the above, and would also add that you should factor in the room as well. If you treated your room to sound ideal with the stereo K&H setup, you would need to further treat it to optimize the sound with three more O300 cabinets——which, of course, means an even lighter wallet.
I would agree with your idea of buying 5 medium-quality speakers and a sub and using it as a separate system. It would provide a nice opportunity to compare your stereo mixes on a lower-quality set of loudspeakers, as well.