Recent research has shown that speakers are sensitive to non-contrastive phonetic detail present in nonnative speech (e.g. Escudero et al. 2012; Wilson et al. 2014). Difficulties in interpreting and implementing unfamiliar phonetic variation can lead nonnative speakers to modify second language forms by vowel epenthesis and other changes. These difficulties may be exacerbated in the classroom, as previous studies have found that classroom acoustics have a detrimental effect on listeners’ ability to identify nonnative sounds and words (e.g. Takata and Nábělek, 1990). Here we compare the effects of two acoustic environments – a sound booth and a classroom – on English speakers’ ability to process and produce unfamiliar consonant sequences in an immediate shadowing task. A number of acoustic–phonetic properties were manipulated to create variants of word-initial obstruent–obstruent and obstruent–nasal clusters. The acoustic manipulations significantly affected English speakers’ correct productions and detailed error patterns in both the sound booth and the classroom, suggesting that the relevant acoustic detail is not substantially degraded by classroom acoustics. However, differences in the response patterns in the two environments indicate that the classroom setting does affect how speakers interpret nonnative phonetic detail for the purpose of determining their production targets.