IFA
emu10k_write_reg(devc, IFA, voice, 0xffff);
emu10k_write_reg(devc, IFA, voice, 0xff00);
emu10k_write_reg(devc, IFA, voice, 0xffff);
emu10k_write_reg(devc, IFA, voice, 0xffff);
emu10k_write_reg(devc, IFA, voice + 1, 0xffff);