Zen Mod said:
There is some indication that this combination works quite well, i.e. you can have a smallish fullranger (4-5") in a sealed box, mated with a good sub. Dave (Planet 10) did something similar with the Fonken+Sub and as far as I understand it sounds good. So, it's more a question out of curiosity, to see how close this can get to an OB sound.
Second, this article should be easity to write, and should be a warm-up for what we all are waiting, a series of articles on bi-amped Open Baffles a'la Papa style.
Regards,
Vix
Indy
Hi Nelson,
Me again. I was contemplating about B4. Actually, I already built a sort. The missing part that I want to implement now is a notch filter. I need it since a use Visaton B200, and it's definitely a better idea to use a notch filter on a line level, than L-R filter before the speaker.
Referring to the schematic in the post #1780,
I have two questions:
1. Can you tell us something more about the choke that you are using? Is it possible for us DIY-ers to wind one that would work satisfactorily? Moreover, did you desing that notch filter having one specific fullranger in mind, or it can be tweaked to accomodate various response corrections?
2. Is there any particular reason, that the notch is placed after the high-pass section, and not before? If the B4 is driven from the low source impedance, this shouldn't matter?
Thanks a lot,
Vix
Me again. I was contemplating about B4. Actually, I already built a sort. The missing part that I want to implement now is a notch filter. I need it since a use Visaton B200, and it's definitely a better idea to use a notch filter on a line level, than L-R filter before the speaker.
Referring to the schematic in the post #1780,
I have two questions:
1. Can you tell us something more about the choke that you are using? Is it possible for us DIY-ers to wind one that would work satisfactorily? Moreover, did you desing that notch filter having one specific fullranger in mind, or it can be tweaked to accomodate various response corrections?
2. Is there any particular reason, that the notch is placed after the high-pass section, and not before? If the B4 is driven from the low source impedance, this shouldn't matter?
Thanks a lot,
Vix
1) Nothing exotic. Digikey has them
2) No reason. Actually in the B4 prototypes the notch is before the high pass.
Right now there are 10 B4's in existence as a shake-out of the design. It will be
simpler and less feature-ridden when it goes to production, which will be after I
decide what's really useful and what's not.
2) No reason. Actually in the B4 prototypes the notch is before the high pass.
Right now there are 10 B4's in existence as a shake-out of the design. It will be
simpler and less feature-ridden when it goes to production, which will be after I
decide what's really useful and what's not.
Rat's nest
Here is the 1/2 of wanna be B4...
Lazy me, I just salvaged me Jfet Boz and built a high-pass active crossover for OB use.B1 buffer is the basis. Thank you Nelson and Zen Mod! Thanks to Nelson's advice from another thread, I trimmed the Q and altered a crossover frequency to 150 Hz. Now it sounds pretty good.
Yet, something is still bugging me, and I have to ask Nelson: Low pass. If I recall correctly, on your "small" OB's, you mentioned that the frequency is around 100 Hz 12 db/oct. But I could not understand what alignment it is: Linkitz-Riley (at -6 db), Bessel, Butterworth or...
Thank you very much,
Vix
Here is the 1/2 of wanna be B4...
Lazy me, I just salvaged me Jfet Boz and built a high-pass active crossover for OB use.B1 buffer is the basis. Thank you Nelson and Zen Mod! Thanks to Nelson's advice from another thread, I trimmed the Q and altered a crossover frequency to 150 Hz. Now it sounds pretty good.
Yet, something is still bugging me, and I have to ask Nelson: Low pass. If I recall correctly, on your "small" OB's, you mentioned that the frequency is around 100 Hz 12 db/oct. But I could not understand what alignment it is: Linkitz-Riley (at -6 db), Bessel, Butterworth or...
Thank you very much,
Vix
Attachments
Re: Rat's nest
I'm not guilty for anything , that's certainly mistake .........
http://en.wikipedia.org/wiki/Linkwitz-Riley_filter
upper right corner of page will give you at least few more names/types
use your imagination
tip : you can always trim value of one part in filter , altering Q somewhat more than Fc
or - make your own crazy net , calculating desired Q from crazy values , which all have pretty same Fc ............... but - don't go too far
Vix said:Here is the 1/2 of wanna be B4...
Lazy me, I just salvaged me Jfet Boz and built a high-pass active crossover for OB use.B1 buffer is the basis. Thank you Nelson and Zen Mod! ...........
I'm not guilty for anything , that's certainly mistake .........
http://en.wikipedia.org/wiki/Linkwitz-Riley_filter
upper right corner of page will give you at least few more names/types
use your imagination
tip : you can always trim value of one part in filter , altering Q somewhat more than Fc
or - make your own crazy net , calculating desired Q from crazy values , which all have pretty same Fc ............... but - don't go too far
Thanks!
I forgot to mention, there is also a notch filter in the circuit I posted. Basically it is the one designed by Geoff H:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=99662&highlight=
With the somewhat scaled values: (100 k resistors were decreased to 27 K, also the input of the B1 buffer after the high-pass circuit was tuned to 27K-it is also the resistor which refereces gate to ground). While not ideal , it is an alternative to the passive LR correction that Visaton B200 needs (despite the phase plug).
Nelson, just a thought: If you were using an F2 amp instead of F3 for the fullranger in the OB, would you then prefer a passive equalization (notch filter). -the ones that you had described in here:
http://www.firstwatt.com/downloads/cs-amps-speakers.pdf
Regards,
Vix
I forgot to mention, there is also a notch filter in the circuit I posted. Basically it is the one designed by Geoff H:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=99662&highlight=
With the somewhat scaled values: (100 k resistors were decreased to 27 K, also the input of the B1 buffer after the high-pass circuit was tuned to 27K-it is also the resistor which refereces gate to ground). While not ideal , it is an alternative to the passive LR correction that Visaton B200 needs (despite the phase plug).
Nelson, just a thought: If you were using an F2 amp instead of F3 for the fullranger in the OB, would you then prefer a passive equalization (notch filter). -the ones that you had described in here:
http://www.firstwatt.com/downloads/cs-amps-speakers.pdf
Regards,
Vix
Nelson Pass said:
If you use a cap you will have a much lower input impedance to that
filter at the top end. In a variety of cases, the impedance will to
too low for the passive JFET buffer to have low distortion.
Dear Nelson,
thank you for your reply.
I'm unclear about your answer.
Do you mean that with the added cap the load will be to low? Then will a complementary buffer or as Vix suggested scale the compnents do the job?
Do you mean that the input impedance will be to low and that we are at risk of instability? Then will a 1k resitance in serie do the job?
Best regards.
Philippe (who appologize for is limited english)
Happy Manu, just got rid today of donuts-buzzing-like-a-loud-razor-problem on my Aleph 5 (Papa, btw, be praised in eternity for this jewel).
DC filter etc. didn't help at all.
Changing Trannies to other ones (in that case black potted talema toroids from farnell or rs?) cure completely the 'blem.
You don't feel even slightest vibration with hand on it.
Conclusio?
Some trannies that are for sale are real drekk...
Manu
(After some metal surgery new trannies fits perfectly ...)
DC filter etc. didn't help at all.
Changing Trannies to other ones (in that case black potted talema toroids from farnell or rs?) cure completely the 'blem.
You don't feel even slightest vibration with hand on it.
Conclusio?
Some trannies that are for sale are real drekk...
Manu
(After some metal surgery new trannies fits perfectly ...)
Attachments
