['To examine the impact of visual cues, speech materials, age and listening condition on the frequency bandwidth necessary for optimizing speech recognition performance.', "Using a randomized repeated measures design; speech recognition performance was assessed using four speech perception tests presented in quiet and noise in 13 LP filter conditions and presented in multimodalities. Participants' performance data were fitted with a Boltzmann function to determine optimal performance (10% below performance achieved in FBW).", 'Thirty adults (18-63 years) and thirty children (7-12 years) with normal hearing.', 'Visual cues significantly reduced the bandwidth required for optimizing speech recognition performance for listeners. The type of speech material significantly impacted the bandwidth required for optimizing performance. Both groups required significantly less bandwidth in quiet, although children required significantly more than adults. The widest bandwidth required was for the phoneme detection task in noise where children required a bandwidth of 7399 Hz and adults 6674 Hz.'] Do the importance of high-frequency audibility with and without visual cues on speech recognition for listeners with normal hearing?