I posted this over the lengthy Gravity Well thread also, but since some folks will come here for most of their OB information, I figured it worth including in this circle.
I have made the leap, and cut the dust caps off my b200's.
Took me about 30 minutes total, once I gathered the courage to take a sharp blade to my drivers.
I have no measuring gear, and have no stock drivers to compare them to. I have what must be at least 1000 hours on these drivers (been using them in OB for 2 years), and am unsure how many hours Dave put on them when he initially had them.
First and foremost, I would to thank Planet10 (Dave) for his excellent service. Simple transation, easy to work with, and great packaging. The instructions on his website are also quite useful, for those seeking to undertake their own surgery.
http://www.planet10-hifi.com/ - and the b200 specifically here -
http://homepage.mac.com/tlinespeakers/FAL/B200-surgery/B200-surgery.htmlIt was not hard work, just hard to bring myself to start slicing. Once I did, it went along OK. It was challenging to remove enough of the glue ring to get the phase plug in place, and the cone moving freely around it, but some patience, and one sharp Xacto did the trick.
For me, I have really enjoyed these drivers, especially with either my JVC EX-A1, or my Magnavox EL84 amp – great synergy, and a strange ability to throw a centered image from way outside the sweet spot. BUT, the treble absolutely beams, for me, in my room, with the stock driver. When I stand up, the treble fades immediately, until I am double my usual listening distance, then it seems to gel again.
Truthfully, I have many times knelt down in the listening spot, in order to get my ears directly in line with the drivers, and found that the most entrancing, if not comfortable!, way to get the best out of the b200. My best friend heard these with stock drivers, and immediately said – no treble. He is 6’8, I am 5’8. When he took the time to sit on the floor, and get his head closer to where mine normally is, it locked in much better for him.
The addition of the phase plugs does a couple of things. First and foremost, the dispersion of the highs is significantly improved – less urges to kneel in front of my speakers now! The air and dimensionality also seems to be improved. The treble still falls off if I stand at the listening distance (7 feet), but the “sweet” spot is at least 3x the size – ie the shift in FR does not change 1 foot above my listening chair, it is when standing fully, that it is less coherent.
No regrets, this seems well worth the $65 or so, and if careful, you are unlikely to damage anything.
Recommended, IF you personally find that the treble beams for you.
Not sure if that really communciates what I am hearing, but I am happy to try and field questions, as we play along together.