This is necessary. When buying balcony aluminum alloy doors and windows, avoid choosing single-cavity thin-walled aluminum alloy, because such windows are easily penetrated by sound. The ability to block noise is also weakened. Multi-cavity aluminum alloy profile with broken bridge should be selected, and its wall thickness is thicker than that of ordinary aluminum alloy doors and windows, so the sound is not easy to penetrate. The multi-cavity of doors and windows are aluminum alloy profiles, which are extruded into the same cavity as required.