Orientation... Gable roof.... best set up for acoustics on long or short wall?

we are building a house with a large gabled room above the garage to be our music room. The total dimension is 39' long 24' wide and 15' high at the ridge line of the gable.

This will leave a listening/music room area of 29'x24'

I am a retired carpenter builder 45 yrs exp. So let me try to understand the situation better

I believe what you have is a bonus room above the 24 x 39 garage. Is this correct? Then the 15 ft high ridge is measured from the floor of the room and NOT the garage floor. is that correct? Apparently you have a very steep roof. What is the roof pitch? I could do better IF I could see the print. But at this point, I'm questioning IF your room is really going to be 24 x 29. The 29' will stay the same . But because of the slope of the rafters and knee wall, the 24' is going to change and be smaller IMO. This is based on what little info I have and my experience

Whatever the case, I would still run the speakers firing down the 29' way

Thanks for your reply. You are right, the garage has a height of 9' then the room above is 15' from its floor to the ridge. The roof pitch is 12/12. I will continue to try and attach and image. Thanks again for your thoughts.

https://1drv.ms/u/s!AuJ3GEEhui8Sg9Mx_H2Aiq7bnnclbw

This is the garage with the music room above. There is an identical dormer on the front side of the garage. 

OK Nice. The picture helps.. First, the ridge height on a 24 ft run with a 12/12 pitch will be somewhere around 12ft, not 15. But that is of little consequence for the room. However the 3 ft knee wall will come in appx 3 ft on each side so that cuts down the room from 24 to 18ft. Still not a bad size. Plus there will be another 3 ft in from the knee wall to get a 6 ft ceiling height. Still not bad. You still end up with an 18 x 29 space. Also these are approximate numbers but still pretty close

Now to the dormers. 10 ft on each side will make a space of 10 x 24. across. This is going to throw a kink in firing longways IMO. However I’m not sure that firing across is any better. There are ways to get it better but it involves design changes. And that may not be possible if you have already started or if the house is already built. I think you are going to have to experiment with setup

The ridge run will be 39' with 10' of that run taken up with a bathroom and bar/cabana area below. So leaving roughly 29' long x 24' wide room for listening. I appreciate your perception given your long experience in building. I hope I have described things correctly. Best wishes.

I think your 18'x29' estimate, with the 10x24 blow outs for the dormers on each side makes sense given the considerations that you mentioned. Thanks again.

Here is the front view of the garage with music room above.https://onedrive.live.com/?cid=122FBA21411877E2&id=122FBA21411877E2%2157271&parId=122FBA21411877E2%2157269&o=OneUp

Nice place. I would start with listening direction on axis with the crest of the roof. I would not think having the reflections on the ceiling behind you a good thing acoustically. Hopefully it also allows you to pull the speakers out further from the wall as well. 

So what is your equipment. Big horns, full sized standing speakers, stand mount? Electronics?

Currently my system consists of the Prima Luna HP Integrated, Border Patrol DAC and Viking Berlin horn speakers, which are incredible. I am contemplating, due to the room size, selling the Berlin's and considering Pure Audio Project Classic or Quintet 15. My other thoughts are the Gershman Grande Avante Guard speakers and if I win the lottery, maybe the Volti Vittora's. I am exploring the Lyngdorf line of  amps as well, as I hear so many good things about their room correction feature. However, I do love the tube sound of the Prima Luna with the option to switch from Ultra Linear to Triode with the press of the remote. I have both the standard EL 34's and the KT150's. Fun hobby.... costs about the same as a pool... but it can travel with ya when you move. Cheers

@montbren 

I'm glad I could help. FWIW a 12/12 pitch simply means that for every 12 inches horizontally the roof will rise 12 inches vertically. An 8/12 pitch will rise 8 inches and so on. I would also recommend that you make provisions to get the hot air out of the attic space above your room. It is basically a Cape Cod design which have a tendency to get very hot in upstairs rooms in the hot summer. I suspect you will need a fan  in the gable to evacuate the hot air along with the standard ridge & soffit  vents. This comes from my time living in a cape cod type house with room upstairs. Otherwise, enjoy the journey. You will have a nice space. OH I like my tubes also 😉

Hey There, thank you again for your input. We will be using SIPS (structurally insulated panels) for the roof, so there will be no attic. The walls will be ICF. I am working with our HVAC guy on how best to make this space comfortable. Lots to consider. I really appreciate your insights and assistance. Cheers