What volume for my speakers

Hi folks, 

I’m new to this and really struggling. I want to make two speaker boxes from 18mm mdf for my shed using 2 Kenwood 170mm 200watt speakers. I thought it would be easy to find out the best box volume using one of the many online calculators out there, sadly it isn’t as the things they ask on the calculators don’t refer to anything I have on the speaker box. 

I have the following info, could anyone tell me how to work out the best volume/size/ shape etc. 

The speakers are not listed on this site. They are Kenwood KFC-PSR700

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The Kenwood KFC-PSR700 are coaxial car speakers. All of these types of speakers are optimised to use like door speakers, or rear baffle speakers in cars - basically infinite baffle: the speaker's front wave is completely separated from the back wave - this means practically a huge box, because the volume basically does not matter, just needs to be "big".

It means in practice that these types of speakers are performing well in every car door - all cars have different doors -> different internal volumes, but the door's volume is not as huge as if the speaker is installed in rear baffle where the "box" is the whole trunk + all cars have different trunks, and the speaker still performing OK.

Maybe this is the reason why are not aviable nowhere TS parameters for this speaker which you need for desiging a proper box for this speaker. Yes, there are methods how to measure them, but anyways, in my opinion try to measure somehow your door's internal volume on your car, then try to design CLOSED box using that volume. In my opinion it will be not compact but usable, just the low bass will sound not as in a car, because of the car's cabin gain.

The other thing: I have a pair of Vibe Edge ED205 speakers in my car - optimised in similar way as your Kenwood. Once I found the TS parameters for that, and tried to design a box for them, and basically all speaker designers are suggested for these speakers boxes with negative or really huge volumes (like an average room in a house) - another example why it will be OK to design a box for your Kenwood the way as I mentioned above.

Watch out for the power, because 200 watts is the peak (max) power, but input signal for this speakers needs to be at the continous (RMS / rated) power's level which is 50 watts - to not blow out the speaker.

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