Originally posted by filmslayer
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Originally posted by rpb View PostDo you have any coils near .05mH, or caps around the .1 or .2 uf range?
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The woofer is probably 89dB, but on an infinite baffle. It looses 6dB due to baffle step. So, depending on how you measure it, the spl looks different. It's probably 89dB at 500hz, and looks lower at 100hz.
I didn't mean to imply that you were off. There's a hundred ways to do this x-over. Mines just an initial sim. I'd need to listen and make 5 or 6 changes to get close to acceptable. There's always compromises due to cost, or impedance issues, or simply the work involved in wiring 20 to 30 parts together without making a mistake. You like the results. That's all that matters. I make so many x-overs for my speakers that I can't decide which one to make final. I have lots of parts on hand, so it costs me nothing to try different x-over points, slopes, etc. I hook it all up with jumpers on the floor near the speakers. Then I fix a drink, and evaluate the x-over for the evening. Sometimes a x-over is great with a Nora Jones tune, but not so great with Cream at higher spl. I want both if I can achieve it.
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New sim.
woofer
4.7mH and 40uf
mid
highpass 90uf cap, and 1mH shunt.
lowpass .2mH, and 30uf shunt cap.
padding 2 ohms before the x-over, and a 12 ohm shunt in parallel with the mids.
tweeter
3rd order 3uf, .2mH shunt, 8uf
padding 5 ohms after the x-over, and 12 ohms in parallel with the tweeter.
Maybe I translated that right.
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You could combine your 2.4mH and 4.7mH to make a 7.1mH. I made a nice 350hz x-over sim using that value.
You will need about a 90uf cap, and 2mH coil for the mid highpass. Or a 1mH, and 120uf. something in between works too. The rest stays the same. This is the x-over point that I would probably attempt if they were my speakers.
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Originally posted by rpb View PostNew sim.
woofer
4.7mH and 40uf
mid
highpass 90uf cap, and 1mH shunt.
lowpass .2mH, and 30uf shunt cap.
padding 2 ohms before the x-over, and a 12 ohm shunt in parallel with the mids.
tweeter
3rd order 3uf, .2mH shunt, 8uf
padding 5 ohms after the x-over, and 12 ohms in parallel with the tweeter.
Maybe I translated that right.
i have all this but the two 12 ohms . not feeling to good today though , i think i drank too much last night ....
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The 12 ohm resistor value can likely be changed without hurting anything. See what it looks like with xsim, and tweak the values to something you have on hand. If you eventually order parts, I think the mid lowpass could be improved a little. I'd try to push down the 10k breakup some more. If you look closely, you can see that it is affecting the summation at 10k slightly, but that's only on axis. I'm sure that the mid 10k peak drops off at 20 degrees or more, so it's likely a minor issue.
Maybe you could make a .05mH coil. I have some old coils that look like good wire donors, you probably do too.
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I found my acoustic offsets for my drivers. The dimensions of the ds90 and 10f are incredibly similar so should be pretty applicable. I used the instructions in Jeff’s white paper using omnimic and pcd.
My woofer and mid are surface mounted, tweeter is flush. Tweeter is considered zero for my measurements. I found the acoustic center of the mid to actually be ahead of the ribbon. Mid: +13mm, woofer: -25mm. Since yours are flushed this would correct to: mid: +9.5mm, woofer: -30mm. These numbers are for pcd, which you enter your driver spacing and it further corrects the distances.
My understanding of xsim (I may not have this right) is because of the ability to only enter the z axis that you need to use the Pythagorean theorem to determine the addition offset due to the increased distance from woofer to ear than the tweeter. If this is the case, I estimated your c to c spacing of t to m to be 4” and t to w to be 16”. I used an 8’ listening distance. If my understanding and math is correct this moves the mid centers back an approximate additional 2mm and the woofer 33mm. So if I managed to get this all correct, the xsim z axis for your mids would be +7.5mm and woofer -63mm. Apologies if this is wrong.
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The tweeter circuit is wrong. Coil in the middle shunts to ground.
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Originally posted by rpb View PostI simmed with the mids in parallel. It looks like your sim shows them in series. Hopefully, that's the problem.
that was it ,
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