Just a thought. IF, you do buy your condo, DO NOT plan a room within a room design on anything but the first floor unless it is engineered. This type of design, if built correctly, is extremely heavy and could overload the structural elements. But if you only plan on adding mass to the existing walls that is ok to a point, as the load bearing walls are designed for it. However, IF your studio is going to utilize the existing floor, NO amount of mass added to walls and ceiling will prevent structural transmittal of sound throughout the whole condo structure by way of the floor. This is key element in low frequency transmission. EVEN CONCRETE. Thats why true room within a room designs, utilize their own SEPERATE concrete foundations. Some float a concrete floor with embedded springs, to float it on the existing concrete slabs.
I'm not trying to rain on anyones parade here, but it is difficult enough to build soundproofing elements in structures that are not sensitive to structural transmission. But when you are confronted with this reality, make no mistake. You are bitting off a chunk of expertise to REALLY accomplish it. You literally could waste many thousands of dollars in soundproofing materials, only to find it does little to prevent your neighbors from feeling as well as hearing your sessions. I know, you and others may scoff, but its just a word of warning. Before you pound ONE NAIL, you should investigate all avenues of the existing construction. As well as the existing HVAC. That alone is enough to negate the same dollars spent on soundproofing. Soundproofing is a misnomer if not thoroughly understood. And if you don't believe me, far be it from me to twist your arm, but lets put it this way.
A noted acoustician in europe told me of an experimental building in which they built a concrete inner shell, which was a room floated within another concrete outer shell. They had a sealed access that they could enter, and close the access. When finished, they proceeded with a simple test. They fired a 9 mm pistol on the interior of the inner shell. No sound was detected on the exterior, in a 360 degree radius around the outer shell at one meter. HOWEVER, when a small wooden wedge was driven into the airspace dividing the two concrete shells, whereby it TOUCHED both shells, a small portable radio placed in the inner room, could clearly be heard in all directions on the outside of the exterior shell. Your floors are tied to the structure at MANY points.
Structural transmission is not a myth. But don't take my word for it. Its your money.
I'm just trying to prevent one of Murphys laws from makeing an appearance, which reads something like "a fool and his money soon part ways".
Cheers.
fitZ
& then make the basement a soundproof room (professionally done), thus making me & a band rock out & record till 2AM in the morning without any other units (neighbors) hearing any of it! (unless somebody opens a door lol).
