R25 insulation will virtually eliminate all midrange and treble frequencies. Attenuating bass frequencies is a whole different ball game. Bass frequencies can set your drywall into a resonant rampage. Since wooden studs are connected to the drywall, the studs can also resonate as well. Thus the bass can be transmitted throughout the entire house. That's where dRC-1 and dRC-2 sound channels can help...a lot! The above sound channels are positioned between the drywall and the studs. The sound channels act as a buffer and absorb the bass vibrations without transmitting too much bass to the studs. This is where ASC wall damp pads are useful. The wall damp pads are very effective in turning bass vibrations into heat. Yes, the system is very expensive. The whole isowall treatment costs about three thousand dollars for an average sound room. This processing includes more than a thousand wall damp pads, dRC-2 sound channels for the ceiling , dRC-1 sound channels for the walls, half inch thick felt strips that line the corners of the room at the floor, walls, and ceiling. Adhesive and step by step instructions are also included. You provide the studs, drywall, insulation, screws, and elbow grease. You could cut corners and buy only the dRC-1+2 sound channels without the wall damp pads. You could use silicone adhesive instead of wall damp, although it's not as effective. I would still recommend two layers of dry wall instead of one. The added mass helps to stop the resonance. Also it is important to use GREEN board first, and REGULAR dry wall board second. Each resonates at a different frequency and has a tendency to neutralize the resonance of the other. While hitting a wall without any treatment you will hear a BOOM sound. With the intermediate treatment you will hear a THUMP sound. With the full iso-wall treatment using wall damp material you will hear only a deadend THUD sound. Basically it all boils down to what you can tolerate with room wall resonance: BOOM!, THUMP!, or THUD!