Cards on table - I have very little support for the hi-fi fraternity with their anti-physics viewpoints on all kinds of crazy thing, including the need to have to burn in loudspeakers. I'm now having to think very hard to explain a recent experience. I thought I'd share it to see if anyone else has views on what is happening here. Not studio speakers, but JBL VRX932LA-1 PA speakers. This design is not really a line array, although most people talk about them in this way, but they're a constant curvature speaker. Our small business does a lot of theatre work, and for one venue we work in frequently, it's not very tall, but very wide and very deep with over 1000 seats on one level. We have no need for mega loudness, but being able to manage the throw is vital. We can't use delays because there's simply no way to hang them because in 50% of the space the ceiling is far too low and the people would be able to touch them. So a speaker position near the pros arch is the only possible place for speakers. These JBLs can have their HF adjusted to add 3dB for the distant seats and pull it back 3dB for the close ones to avoid taking their heads off with cymbals etc. Trouble is, our budget didn't cope with the purchase price for 2 subs and 6 tops. I searched worldwide, as they're not very popular and a ten year old design product probably in it's last stages of availability. I found a couple of dealers with a mix of brand new, and customer returns and got what I need from them, in total. It's arriving slowly and just waiting for the subs and 2 more tops, but I have a strange problem. Three boxes (2 from dealer A and one from dealer B) do show signs of having been used - which is fine. Tiny marks, and one has had a bit of touch up paint on a deepish but small gouge. They told me about it, and it's OK with me. The last box was still in the original wrapping and the box showed no signs of being opened. This is/was the problem. To check how the switches function on the -3/0/+3dB settings I played my usual test tracks and the 'virgin' box sounded a bit thinner? I switched from music to pink noise, and all of them do the same things with the switches, but the unopened speaker sounded different. Pulled out a mic and looked at the response on the pink noise and a tone sweep. The different speaker has less output at just above 500Hz, and then another trough although a bit smaller at 1200Hz. Using a 32 band EQ, I could quite easily restore the response to match the others. I had a think. These speakers can also be bi-amped, and I realised that if I switched the speaker to this setting, then with no connection to the 3 HF drivers, it would just be the LF driver working, and this confirmed the driver was the problem, not the HF units. I sent it some music and did some more tests and tried it at various volume levels. In my studio it was too loud for comfort so I threw some blankets over it to tame the volume a bit. Then I had a phone call and had to dash off to fix something for a client. When I got back, I forgot the studio, and with the doors working fine, I didn't hear it and forgot. This morning, I remembered - 24 hours later the music on loop and the thing still blaring away. It now sounds exactly the same as the others! I have always discounted the burning in theory as rubbish, and couldn't find any sound reason why blasting a speaker for a bit changed the sound - but it has. A 100% fact. The response on screen now is so close to the others I cannot compare them? I wonder if perhaps the voice coil was perhaps rubbing a bit in the slot, or maybe the surround rubber was a bit stiff, but I don't know? I now have 4 matched speakers. Has anyone else had something similar? I've always been content my opinion on burning is was solid, but clearly I was wrong. I'm assuming whatever the loud music for 20 hours or so did was fix something? Any opinions on what's happened? I'm more than happy with the speakers now, and we've got a good system for around half the normal price and that's included the shipping. My remaining speakers are on a ship somewhere. I accepted the sea freight option rather than air freight because of cost, and time isn't a problem ..... but it has been at sea a fair while now from Mexico!