Apparently the lamellas were a challenge as opposed to an acoustic improvement, what with wood not being acoustically transparent and all that...
I suppose the bass not relying on being directional was a help, plus popping the acoustic lens on the top out of the way helped too. I'm sure Geoff will confirm or deny, but I was told it wasn't done to help the sound - it was a design thing.
One thing I did forget to mention though was the speakers sounded sharper when I was stood up listening to them - and when I crouched down they lost a little of that in my opinion. I'd be interested to hear Geoff's views on that.
I don't have anything to contradict what you were told, Lee.
However, I would add a couple of things:
The Lamellae
We did the final sound design of the BeoLab 18's with the final assembly - so the engineers measured the acoustic performance with and without lamellae (so we knew the resulting effect). We did the final listening and tuning with the lamellae in place, so, although they have an effect, both with respect to overall magnitude response and directivity, that effect is considered in the tuning.
Tweeter placement
We can see in the measurements that there is a "shadowing" effect in the high frequency bands as you drop to a listening position lower than the tweeter + lens on the top of the loudspeaker. However, this, too was taken into effect during the tuning process. The high frequency balance was set at a listening position of 3 m from the loudspeakers and a height of about 1.1 m (that's the distance from the floor to my ear when I'm sitting in the listening room - and since everyone in the acoustics department is the same height, I can use me as a "standard"😕). So, if your sofa is the same height as ours, and the distance between your back pockets and your ears is the same as mine (when seated), then you are getting the tuning that we hear in the listening room.
However, as I said (and as you heard), there is a shadow effect - this means that if you stand in front of the speaker, bending a little so that your ear is level with the tweeter, you'll hear a brighter response than when you're sitting. Stand up a little more and you'll probably hear a shadowing effect again. So, the punchline of this story is that - yes, the lens is "aimed" above your head - but we increase the high's a little to get the balance we wanted when you're sitting down. You might get lucky when you're standing up - but that depends on how far away your ears are from your shoes instead of your back pockets - and also how far away you are from the loudspeaker itself.
I would point out, however, that this shadowing effect is present (to varying extents) in all loudspeakers. Try standing and sitting whilst listening to whatever you have and you'll probably notice things changing. The closer you stand while you're doing this, the more the effect, since (partly) you are causing a larger change in the vertical angle to your ear from the tweeter. This is also a good way to get exercise.
cheers
-geoff
If you have questions about or problems with B&O equipment, these should be directed through your dealer and/or B&O's Customer Service department.
I cannot be a "short circuit", bypassing these communication channels.
Thanks
-geoff
