That looks like a 2nd order filter on the low pass, 2nd order on the high and a Zobel.
All of those wires hanging around untaped is asking for a short. Could be made more tidy.
Give the values of the components.
EDIT: scratch that, I just looked at Dave's high res shot.
Unless he's using Bennic NPs for filter.
All of those wires hanging around untaped is asking for a short. Could be made more tidy.
Give the values of the components.
EDIT: scratch that, I just looked at Dave's high res shot.
Unless he's using Bennic NPs for filter.
MJL21193 said:
I second that.
Impedance EQ with resistor and a electrolytic cup.
I usually place and glue all components on one side and do all wiring on the back. I also silicon the wires so they don’t hang around like that.
BTW, it is not MTM. True MTM has a tweeter in the middle and the distance between the center of the tweeter and each woofer are equal to a length of the sound wave at the crossover frequency. I had an idea that we could backtrack crossover point from the location of the drivers.
Is this my correct understanding that you have 2 main speakers ported and center closed?
Yes the mains are ported, they are the cabinets that I referenced the sizes of before and the drawing that he posted for me is. The mains are not MTM, the center is MTM, is sealed, and is smaller. I could measure that cabinet or look for my notes on that if it would help. Same drivers and x-overs as the mains, I wanted to maintain the timbre for the HT application.
Does the x-over that I posted make sense to you with the drivers being used, and do you still think that the 120s won't help? I do know the model he built the crossovers for was for the 120, though he did say I might need a 1 or 2 ohm resister on it. He also used a scanspeak revelator with this crossover and woofers as well.
Does the x-over that I posted make sense to you with the drivers being used, and do you still think that the 120s won't help? I do know the model he built the crossovers for was for the 120, though he did say I might need a 1 or 2 ohm resister on it. He also used a scanspeak revelator with this crossover and woofers as well.
planet10 said:
I agree with the schematic, but it's a little funny: 2nd order on both high pass and lowpass give near equal values for the inductors and the caps. Therefore, there should be another high value cap (that small blue one doesn't look like 10uF). Unless, the filters are mixed.
My guess is 2nd order Butterworth on the tweeter@ 2000hz and 2nd order LR @2000hz for the woofers. Coils would be .6mH on the tweeter and .95mH on the woofers.
100% agree Dave, it should be reconfigured as 2.5.
I believe the blue cap is 9.1uf.
It's funny you should say that because the Zetag engineer origionally gave me a design for a 2 1/2 way crossover, he even sent me the parts. That is what they used on the prototype they built. I built the crossovers the way he designed them and the speakers sounded really bad. I think I still have his origional scematic and I know I still have the xovers. I will post the scematic if I can find it.
What do you think of the x-over design?
Thanks for your help.
It's funny you should say that because the Zetag engineer origionally gave me a design for a 2 1/2 way crossover, he even sent me the parts. That is what they used on the prototype they built. I built the crossovers the way he designed them and the speakers sounded really bad. I think I still have his origional scematic and I know I still have the xovers. I will post the scematic if I can find it.
What do you think of the x-over design?
Thanks for your help.
fantfool said:
fantfool said:
IF the tweeter is filtered with a 2nd order Butterworth with these values you have tweeter impedance at 4 ohms and the crossover at 2800hz. That doesn't seem bad. Is this the tweeter impedance though?
For the mid woofers, you haven't said what the inductor is on those. Assume that coil is nearly the same (.33mH) and that with the paralleled impedance (the woofers are parallel, right?) and you have a 2nd order Linkwitz-Riley at 2800hz.
This seems reasonable for the drivers involved, though probably not optimized. Better results come from testing to determine the impedance at the crossover region, with the effect of the Zobel counted in. Then a whole system test to see the combined impedance.
I don't see any values on the inducters. The numbers I gave you on the tweeter cap and inductor were from the guy I bought the x-overs from. I just asked him what the x-over points are. I'm sure the Focals are 8 ohm as are all the drivers but I asked him to confirm.
Also, I dug out the information from the Zetag engineer on what the was recommending as to the x-over points for his 2.5 way design. They were 3.2, 2.2, and 2.4, but that tweeter number was based on his tweeter which was a silk dome tweeter, ok but not great.
Also, I dug out the information from the Zetag engineer on what the was recommending as to the x-over points for his 2.5 way design. They were 3.2, 2.2, and 2.4, but that tweeter number was based on his tweeter which was a silk dome tweeter, ok but not great.
fantfool said:
OK, I went to the effort of looking for the specs on the tweeter - TC90, right? Impedance is 6 ohms. At this impedance and with those components, this crossover is no known alignment (not to me anyway).
Woofers DCR (as posted by Dave above) is 5.6. given the Zobel and the assumed crossover point, their parallel impedance should be 3-5 ohms.
Your 2.5 should have only two crossover points. Here is a good article on a 2.5 build, by a genius (pun) in the field.
Nice article! I see the TC120 was used, how did you like it?
OK forget the x-overs I currently have since we are not quite sure what thet are, if you were to design a x-over for the given drivers, how would you recommend doing it to optomise those drivers, and would you use the TC90 or the 120?
OK forget the x-overs I currently have since we are not quite sure what thet are, if you were to design a x-over for the given drivers, how would you recommend doing it to optomise those drivers, and would you use the TC90 or the 120?
This is roughly, what’s going to happen with the info that we have. I haven’t calculated Zobel or effects of the box and port or closed box. I also played with the inductor value for the woofer and 0.5 gives well-mannered results. According to the graph and my previous guess, TC90 is going to like 4th order x-over more then 2nd. It is quite possible to finish this x-over or design a better one. TC-90 definitely needs impedance EQ also.
At this point, it makes sense to decide in which direction to go.
1) Are we going to dump existing x-overs and start from scratch?
2) Are you going to keep TC90 or your hart is set on TC 120 and no mater you will get them later anyway?
3) Are you going to get woofer tester and get actual measurements on Ztags or just swap them for something better (Seas Prestige comes to mind). Measurements on Ztags are very important either way.
4) Are u going about it from $$$ point of view or it’s not really an issue?
TC90 vs. TC 120.
Fant, you keep on asking, “how do u like them”. It’s a subjective question. If you use either driver with improper x-over, they both will sound like a rusted door hinge.
If you design a good x-over I am sure they will sound fine. I mean both of these drivers are on the par with their competitors from Scan-Speak, Seas and Eton.
Now, this is a generalization that I have from both drivers parameters.
TC 90 is more suitable for a 3 way. It’s higher Fs makes more difficult to cross over in a 2-way system. It also seams to be linear except for a FS bump, which falls right at the soprano. I’d say a minimum x-over is 2500hz
TC120
Lower Fs, more money. My concern is bumpiness in the 3500hz region. Perhaps Zobel could correct it.
My guess is that with proper x-over TC-90 will sound better or should I say more pleasant.
Either driver is fine though.
At this point, it makes sense to decide in which direction to go.
1) Are we going to dump existing x-overs and start from scratch?
2) Are you going to keep TC90 or your hart is set on TC 120 and no mater you will get them later anyway?
3) Are you going to get woofer tester and get actual measurements on Ztags or just swap them for something better (Seas Prestige comes to mind). Measurements on Ztags are very important either way.
4) Are u going about it from $$$ point of view or it’s not really an issue?
TC90 vs. TC 120.
Fant, you keep on asking, “how do u like them”. It’s a subjective question. If you use either driver with improper x-over, they both will sound like a rusted door hinge.
If you design a good x-over I am sure they will sound fine. I mean both of these drivers are on the par with their competitors from Scan-Speak, Seas and Eton.
Now, this is a generalization that I have from both drivers parameters.
TC 90 is more suitable for a 3 way. It’s higher Fs makes more difficult to cross over in a 2-way system. It also seams to be linear except for a FS bump, which falls right at the soprano. I’d say a minimum x-over is 2500hz
TC120
Lower Fs, more money. My concern is bumpiness in the 3500hz region. Perhaps Zobel could correct it.
My guess is that with proper x-over TC-90 will sound better or should I say more pleasant.
Either driver is fine though.
Attachments
I am not intrested in spending more money if I don't have to. Realistically, I doubt whether I can spend no money and still improve the speakers, but whether I spend the money on drivers or x-overs makes no difference to me. I really just want to correct the issue. The reason I go back to the 120 is, currently this is a 2 way system and the 120 is certainly better for that application. I kind of like the idea of a 2.5 way system as well, I think the Zetag engineers came to the conclusion that with those woofers it was a better design. The problem was the guy I talked to had his son design the x-over and it wasn't good. I am looking at it now, it consists of 3 inductors, and 3 capacitors. I don't know the value of the inductors, but 1 of the caps just says Zetag Corp MP475J 200V8C, the other 2 say MP355J 200VDC.
The guy responded that the x-over point on the current x-over is 2800 hz and he said all drivers are 8 ohms. But, Planet said the TC90 was 6 ohm.........
Thanks again for your help.
The guy responded that the x-over point on the current x-over is 2800 hz and he said all drivers are 8 ohms. But, Planet said the TC90 was 6 ohm.........
Thanks again for your help.
Well, in order to design a good crossover you need the measurements from the drivers. If you don’t have precise data, you can’t design an accurate x-over. The measurements for TC90 or TC120 are available. I’ve posted a link to the Speaker city page with Focal TC90 and it’s 6ohm driver.
The problem is your Ztag driver. We don’t know if they are good or bad, we barely have enough data to do an x-over. Have you measured DC resistance of Ztags?
Anything could be done and designing and building new x-over is more of a money saving way. Considering that TC120 is a $100 driver and you’d need 3 of them and the tweeter is not exactly a problem, I would much rather spend my money on capacitors and inductors. Solen caps are fine and for HT iron core inductors will do ok but if you want to be fancy, could go with air core. You could also call Madisound and see if it make more sense for you to send them Ztag and have them measure it.
The problem is your Ztag driver. We don’t know if they are good or bad, we barely have enough data to do an x-over. Have you measured DC resistance of Ztags?
Anything could be done and designing and building new x-over is more of a money saving way. Considering that TC120 is a $100 driver and you’d need 3 of them and the tweeter is not exactly a problem, I would much rather spend my money on capacitors and inductors. Solen caps are fine and for HT iron core inductors will do ok but if you want to be fancy, could go with air core. You could also call Madisound and see if it make more sense for you to send them Ztag and have them measure it.
Ok I sent the Zetag engineer an e-mail requesting the T/S information of the Zetags. He said he didn't remember off the top of his head but he would try to find the paperwork and e-mail me back this week.
If this doesn't pan out, I will see about getting the information on the Zetags one way or another. You are right in that without this information, I could spend more money and end up no better off or worse than I am now. As I said, they don't sound bad, they just don't sound great.
Thanks to all for your help.
If this doesn't pan out, I will see about getting the information on the Zetags one way or another. You are right in that without this information, I could spend more money and end up no better off or worse than I am now. As I said, they don't sound bad, they just don't sound great.
Thanks to all for your help.
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