Visaton B200 - Taming the shout

http://www.audiocircle.com/circles/index.php?topic=31582.0

A very good thread for that, and the OB forum has lots of information on the B200

I used this to tame the shout of my Monacor SPH-30X quite successfully:
http://www.audioasylum.com/forums/hug/messages/120394.html

only I placed a potmeter on R3 to adjust the effect, it functions more or less like a midrange eq. fader...but once adjusted I never feel the need to change it again...

Step 1 -- phase plugs...

dave

planet10/ of course i have a bias

Here's what worked well on the Monacor:

Hi Dave, thanks for your great input!

it's a bit off topic, but how does one design a phase plug?
is there a software simulator for it, or is it just trying out all kinds of plugs shapes until response curve looks better?

Though I reserve the term "shout" for whizzer coned drivers, the B200's do beam and have that long gradually rising response. Below is my solution to both. I call them Constant Directivity Dipole WaveGuides (CDDWG's). The narrower dispersion helps match the lower end response with the HF beaming to sound flatter overall. HornResp tells me there's even a few db gain from some slight horn loading below 1khz, which also helps out. When the waveguide runs out of steam, the dipole directivity takes over. I use them with dipole bass augmentation, but they work surprizingly well run full range with a little bass boost.

BTW, Dave I picked up a used pair of 167's that have your phase plugs. Will those fit a B200, since it has the same VC diameter?

I like my phase plugs from Dave for the B200. The sure help the beaming. The rising response can be help with toeing in or out, a notch filter, or hopefully the new toy John is showing.

Had to let miss Jones take a break......running the B200's with Geoff's circuit thru a Mac MR-74 in FM mono & it is delightfull..mixture of silver mica & polystyrene.. I got all SM coming & AB carbon comps for the circuit.. I will try all polystyrene also.. finally the meat of the guitars is correct.. that has been a major problem for me with a few shouty FR's..Dave's plugs do work well, I used them in a pair of fe167e's..But the surgery was a little concerning.. I am not ready yet to carve on the B200's, but with Daves plugs & a PLL circuit to flatten this unit out might be the big ticket.. it now sounds like my FR in OB that I run in a bedroom system.. it is good..great on guitars..absolutely..amplified guitars are crazy hard to get correct..you wouldn't think so ,,but they are. Back on Nora,, she can become very shouty on all 3 of her albums..That is gone.I have tried analog 31 band EQ's.. & WAY to many dang filters after the amp, & all kinds of stuff with these drivers. This is the 1st hope I have had to run the B200 alone..I can handle it fullrange now. Circuit doesn't have the life robbing effect that passive after amp parts seem to have..there is insurtion loss,.but nothing major. I am running passive TVC into 300B PP amp. I have a 27 pre on bench I am building & it should be nice with this filter. My DAC is also output stage by-passed, so not alot of voltage to work with, still it gets with it..But ran from the MR-74 it flat rocks.. & the guitars are meaty & very natural, with the overtones & harmonics actually bieng heard.. I do not think that is the case with the B200 on it's own..Once I get the nerve,, I will try daves plugs & this filter together..that should be a nice combo,..The ribbon B200 combo is getting on my nerve....ribbons are touchy creature..the magic my single 12" alnico in OB does set me on path to return to B200 FR..I also added some bottom end boost to my BASH plates this mourning w/ resistor changes ...NICE..Thanks Geoff..

Geoff H said:

Nice CDDWG's John. I'll never finish my OBs with all these new ideas. Another to consider. Have you posted details?

Click to expand...

Thanks. Want to do measurements first, and have to learn how to do them properly. I got picked on for no graphs by telling too much of what my ears tell me. Plus I want to try some other drivers in them first. The driver mounting baffle is changeable, so any 8" or smaller will work. Before the foam and material lining the 108Esigma's were better, but the lining helps alot with the undersized "throat" for waveguide only action. Just got some F120A's in that deserve a turn too. I listened to them for 3 days without augmentation as pictured, and probably only the B200, higher Q hemp, or Supravox can get away with that, since I like bass.

BTW, I owe thanks to GM for some initial guidance during my planning phase. The idea was to copy Dr. Geddes' Summa concept, but in a dipole layout instead of going omni in the bass and monopole WG on top. I got some side benefits I didn't expect.

Hi!

Geoff, can you please post again the PLL circuit, a bit bigger? I have troubles reading the component values.

I also have B200's and I love/hate them. Tried passive EQ, but was not happy. Sounded a bit dull. Without ant filters, b200's sound lively, but painful.

Dave's phase plugs are a very good idea, but I am still a bit reluctant to cut through the speakers.

Somewhere I read that treating the dustcap with dammar could improve things... Maybe I'll try that. If it doesn't work, I'll cut it altogether and install plugs...

Vix

I'm going to cut the B200's..& use the PLL circuit together,, plugs to kill some beam & the rest in taken care of.
John ,,,Those are crazy nice unit's you built ..impressive stuff.
Geoff, what the heck is ( sot )..?
The values I am running with parts on hand are

+.........51k .....................................................................+ B200
[....200pf.....].......| |
| 1
1 0
0 0
0 k
k |
| 200pf
2700pf |
| .
_.........................................................................................- B200

I am sure this could be tweeked one way or another..but it is definately taken the rise out of the problem area's & is doing positive work to the driver. Well at least as to how I hear it. I am not capable of proper measure ments yet. In do time though I will.
I have 220pf & 2700pf in SM on the way & also some AB CC's for the resistors also coming.. Parts running now are from junk box..alll meausred, but old,, like 40 years old..*s*well cf resistors are new..

My tube amp is 100k input impendance..

Pay no attention to my feebal attempt @ a thrown together schematic, when posted, it all went every which way,,it is NOT correct..just use what Geoff post's if you try it....damn!!!!!!!!!!

Thanks a lot!!