ɪf ðɪ ˌeɪtʃpˈiː kəmpɹˈɛsɚ pɹˈɛʃɚ ɹˈeɪʃɪˌoʊ ɛksˈiːdz ɐbˌaʊt fˈoːɹ.fˈaɪv:wˈʌn, ðˈɛn ðə jˈuːnɪt wɪl pɹˈɑːbəbli hæv vˈɛɹɪəbəl dʒiˈɑːmətɹi ˈaɪ.ˈiː. vˈɛɹɪəbəl stˈeɪɾɚz ɔnðə fˈɜːst fjˈuː stˈeɪdʒᵻz, tə mˌeɪk ðə sˈɜːdʒ lˈaɪn ɔnðə kəmpɹˈɛsɚ mˈæp mˈoːɹ ʃˈæloʊ, tʊ ɐkˈɑːmədˌeɪt ðə ʃˈæloʊ wˈɜːkɪŋ lˈaɪn.
If the HP compressor pressure ratio exceeds about 4.5:1, then the unit will probably have variable geometry (i.e. variable stators) on the first few stages, to make the surge line on the compressor map more shallow, to accommodate the shallow working line.