Hello, here I have what is left from a DIY 2 way loudspeakers:
1- a pair of Seas p21 RE-M. They need refoam sorround.
2- a pair of Peerless 811546 tweeters. They look great.
3- a pair of crossovers as seen in the picture. Also I drew a sketch as best possible.
I got some values: the 1,2 mH coil, the 8 uF polarise cap and the PMT/2R cap (sorry, I drew it as a resistor).
Any ideas what could be the other values? Or may be some popular kit from the 80's?
I would like to get the values before refoaming the woofers.
Also I asked the person who gave me the drivers if he still had the contact from the person who designed and/ or build the speakers.... No luck.
Thanks very much in advance! Any ideas or help is really apprciated!
subirimagenes
1- a pair of Seas p21 RE-M. They need refoam sorround.
2- a pair of Peerless 811546 tweeters. They look great.
3- a pair of crossovers as seen in the picture. Also I drew a sketch as best possible.
I got some values: the 1,2 mH coil, the 8 uF polarise cap and the PMT/2R cap (sorry, I drew it as a resistor).
Any ideas what could be the other values? Or may be some popular kit from the 80's?
I would like to get the values before refoaming the woofers.
Also I asked the person who gave me the drivers if he still had the contact from the person who designed and/ or build the speakers.... No luck.
Thanks very much in advance! Any ideas or help is really apprciated!
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
subirimagenes
For an understanding of crossovers and how they are drawn, please see my blog post here.
For help upgrading an existing crossover, please see here.
If it's drawn correctly it's a small cap used to improve the performance of the 8uF cap. Using a decent modern film cap you should be able to replace both caps with a single good 8.2uF cap or here.
For direct measurements get Dayton DATS V2 or a multi-meter that has good LCR measurements. Cap values of electrolytic capacitors changes over time so those won't be very reliable.
Once you've read my blog on crossover basics, I think what you have is a 2nd order high and 2nd order low pass circuit.
Try redrawing them that way. If you use XSim you can skip the paper and pencil.
Best,
Erik
For help upgrading an existing crossover, please see here.
If it's drawn correctly it's a small cap used to improve the performance of the 8uF cap. Using a decent modern film cap you should be able to replace both caps with a single good 8.2uF cap or here.
For direct measurements get Dayton DATS V2 or a multi-meter that has good LCR measurements. Cap values of electrolytic capacitors changes over time so those won't be very reliable.
Once you've read my blog on crossover basics, I think what you have is a 2nd order high and 2nd order low pass circuit.
Try redrawing them that way. If you use XSim you can skip the paper and pencil.
Best,
Erik
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This speaker uses drivers like in the Mission 737.
8" Polycone bass and soft dome tweeter. Some data below.
You can use second or third order tweeter, and simple bass filter at 3kHz. Well behaved drivers, you see.
Downloads
8" Polycone bass and soft dome tweeter. Some data below.
You can use second or third order tweeter, and simple bass filter at 3kHz. Well behaved drivers, you see.
Downloads
Attachments
Thanks Steve!! I'pll check later during the afternoon the visaton app: not sure if will work on Mac OSX...
The values of the drivers are preset in the Visaton app or did you add them manually?
by the way, one of the resistors, the white block, had writen underneath the value: 22 ohm or could be 2,2 ohm. The thing is they glued the parts where the value is writen so when I ripped them off it takes the writing...
Well Steve, I'll stick to your suggestion, also the values skeched with the Visaton app are very similar. Still got to refoam the woofers which is another challenge.
The values of the drivers are preset in the Visaton app or did you add them manually?
by the way, one of the resistors, the white block, had writen underneath the value: 22 ohm or could be 2,2 ohm. The thing is they glued the parts where the value is writen so when I ripped them off it takes the writing...
Well Steve, I'll stick to your suggestion, also the values skeched with the Visaton app are very similar. Still got to refoam the woofers which is another challenge.
Retrace the schematic now you have an idea how it should pan out.
FWIW, the Vifa P21WO-20-08 is a similar unit though more of a reflex driver IIRC.
Vifa P21WO-20-08 Diameter 215mm
I use a modeller to get a rough idea what is going on. TBH, you could tune this one by ear. 8" Polycones usually need less bass filtering than paper cones, but not much in it. You are not clear what the bass shunt is, if fitted, but usually with a biggish resistance in series with the cap. Near Zobel.
FWIW, the Vifa P21WO-20-08 is a similar unit though more of a reflex driver IIRC.
Vifa P21WO-20-08 Diameter 215mm
I use a modeller to get a rough idea what is going on. TBH, you could tune this one by ear. 8" Polycones usually need less bass filtering than paper cones, but not much in it. You are not clear what the bass shunt is, if fitted, but usually with a biggish resistance in series with the cap. Near Zobel.
Hi John, since I tend to drown and overload in my PM box, can I bring this back to the thread?
http://www.seas.no/images/stories/vintage/pdfdataheet/h0359_p21rey.pdf
That 30L reflex woofer looks a easy to me. Very well-behaved. It really doesn't need much more than a bass coil around 1.5mH IMO. And a port or reflex tube about 5" long and 2" or 3" diameter at a guess.
The circuit below will probably work if you skip the shunt element on the bass or change the resistor from 5.6R to 22R for a 3kHz crossover. The red 4.7R is select on test for tweeter level.
http://www.seas.no/images/stories/vintage/pdfdataheet/h0359_p21rey.pdf
That 30L reflex woofer looks a easy to me. Very well-behaved. It really doesn't need much more than a bass coil around 1.5mH IMO. And a port or reflex tube about 5" long and 2" or 3" diameter at a guess.
The circuit below will probably work if you skip the shunt element on the bass or change the resistor from 5.6R to 22R for a 3kHz crossover. The red 4.7R is select on test for tweeter level.
Attachments
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Hi John, since I tend to drown and overload in my PM box, can I bring this back to the thread?
http://www.seas.no/images/stories/vintage/pdfdataheet/h0359_p21rey.pdf
That 30L reflex woofer looks a easy to me. Very well-behaved. It really doesn't need much more than a bass coil around 1.5mH IMO. And a port or reflex tube about 5" long and 2" or 3" diameter at a guess.
The circuit below will probably work if you skip the shunt element on the bass or change the resistor from 5.6R to 22R for a 3kHz crossover. The red 4.7R is select on test for tweeter level.
THANKS THANKS MANY THANKS
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