Bohlander-Graebner Planars
- Thread starter gaslover
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tomlinmgt
Lunatic Member
Nope, but I do have the Neo3's and am very, very impressed with their performance. I'm anxious to hear your impression of the Neo8's as I'm seriously considering a pair of Neo10's to replace the EMIMs that were harvested from these RSIIa's.
What are you planning on using the 8's in?
- Michael
What are you planning on using the 8's in?
- Michael
gaslover
Active Member
As much as I love my Dayton full-rangers, I'm thinking it's time to experiment/upgrade. I will be crossing the 8's in at 500, lowest point mfr. recommends. These will be powered by my rebuilt/highly modified GAS Grandson (it really sounds like a little tube amp).
My stack of 2x12" on each side will handle 500 & down, powered by the Son of Ampzilla.
My stack of 2x12" on each side will handle 500 & down, powered by the Son of Ampzilla.
Poultrygeist
Lunatic Member
I use the B&G Neo 3s ( see avatar ) with Tang Bands W8-1808 in OB and drive them with their own dedicated T-amp.
They give incredible shimmer and air to the top end and high hats never sounded so good.
They give incredible shimmer and air to the top end and high hats never sounded so good.
tomlinmgt
Lunatic Member
You might want to look into that 500 Hz xover point a little bit more. Read the testimonials/reviews on PE's website. Seems I read somewhere they can only pull off the bottom end of the manufacturer's stated usable range when used in a line source config.
tomlinmgt
Lunatic Member
I like your attitude. :thmbsp:
Just floor it and let's see what the sonofabitch will do!
I did a 2-way with the Neo8 and a 6.5" back about 10 years ago. I remember they sounded pretty good but I had to use a cap in a compensation role like with a horn to get the response flattened out. After doing that there was a bit of a drop way up and the high end (like 18k-20kHz or so) but didn't show up in listening tests. I seem to recall the crossover being somewhere in the 1000-1200Hz range.
Remember that this is from 10 or so years ago so I hope I'm remembering the right driver (I've designed quite a few speakers since then). As I recall, the driver had a rising response that went up roughly 6dB per octave starting somewhere around 3 or 4kHz and going up to about 15kHz. To counter that rising response I put a capacitor in line with the driver (a single cap will have a 6dB/octave falling response as frequency increases). This made the response up to about 15kHz or so pretty flat at the expense of the very highest treble.
Great googly moogly! I can't believe I did that. Yes, of course I meant inductor. Thanks for correcting that. It's not like I do this stuff for a living or anything.
I used an inductor in a manner similar to a cap in a horn compensation circuit to flatten out the rising response.
Egads. I should be beaten for that goof.
StimpyWan
Addicted Member
Parts Express has the BG White Paper for the Neo8 driver. Page 6, shows a schematic, that lists the recommended notch filter:
http://www.parts-express.com/pdf/264-713.pdf
http://www.parts-express.com/pdf/264-713.pdf
What I did was kind of like half a notch filter. A proper notch filter would have preserved the high end of the spectrum at the expense of a slightly more complex filter. At the time I was just looking for simplicity and it ended up sounding pretty good so I left it.
nexus
Super Member
all the planars exhibit a peak in the response. they even call it " Bohlander-Graebner resonance". my old carvers also had this peak caused by the unavoidable cavity resonance from the driving magnets in the frame. not a big deal in practice, just a passive notch is all that is needed, or a para-eq in the front end.
