The sound is very clear, exceptionally fine!
I have used during the 80 lower-medium in a 4-way (ESL PRO) was the fire of God! What I like most, its bowl, its membrane with its aluminum dome, the HP is beautiful! And most importantly, it is very rare today to find a 31cm able to get off at 35Hz and up to 5kz. Excellent value for HP elders who still work and are like new!