Great Midbass but of course need an enclosure to sound their best. Problem is the enclosure is 20 liters optimum sealed. I had to buy the spx-137r's for the front stage because they only need a 5 liter enclosure with a very similar response. Ended up using 2 sets of isobarik spx-177r's in the back for midbass. The isobarik pairing shrunk the box to 10 litres. All in all a fantastic midbass speaker (sounds like no other) but if you are making enclosures it can be tricky. Type X all the way!