| 1 in (25 mm) | Flush-mounted or 1–2 in (25–50 mm) | Primarily high frequencies and some upper midrange, roughly 1,000 Hz and above | Reducing flutter echo and excess brightness in offices, classrooms, and small meeting rooms | Best for limited wall depth. It is generally less effective at controlling low-frequency buildup. |
| 2 in (50 mm) | Flush-mounted or 2 in (50 mm) | Mid and high frequencies; performance generally improves as the air gap increases | Speech-focused rooms, home offices, podcast spaces, and general-purpose wall treatment | A practical starting point for broadband absorption when deep bass control is not the main goal. |
| 3 in (75 mm) | 2–3 in (50–75 mm) | Broader midrange absorption, with better lower-midrange response than thinner panels | Listening rooms, rehearsal rooms, and spaces with noticeable room coloration | Useful when both speech clarity and some reduction of lower-midrange reflections are desired. |
| 4 in (100 mm) | 2–4 in (50–100 mm) | Broadband midrange and upper bass; results depend on material, mounting, and room conditions | Control rooms, music rooms, and rooms with persistent low-mid buildup | A thicker panel and air gap can extend useful absorption lower than a thin, flush-mounted panel, but will not guarantee deep-bass control. |
| 6 in (150 mm) or more | 4–6 in (100–150 mm), where space allows | More useful for lower-frequency absorption than thinner panels; deep bass may still require specialized treatment | Recording rooms, dedicated listening rooms, and spaces where low-frequency ringing is a concern | Consider corner placement and room measurements. For strong bass problems, purpose-designed bass traps may be more appropriate. |