Center Statement build

[matthew1975]

Hello starting my center build. Do these look right

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these crossovers look correct?
First time trying to post some pictures in case they don't show you know why.

[matthew1975]

well the subs picture on the top the capcitor lead is suppose to go in the terminal with the red lead. The second picture is the one I was wanting some feed back on. when I hook all three speakers plus the sub up they all work. I get alot of sound out of the mids, the tweeter seems low. and the subs sonds low with no bass. Also the 8 ohm resister gets supper hot, hot enough to melt a tirestrap into, doe this sound right? Curt, Jim, anyone that has a idea. The picture is not great because It was taken with a iphone but I think it readable enough

[wackii]

well the subs picture on the top the capcitor lead is suppose to go in the terminal with the red lead. The second picture is the one I was wanting some feed back on. when I hook all three speakers plus the sub up they all work. I get alot of sound out of the mids, the tweeter seems low. and the subs sonds low with no bass. Also the 8 ohm resister gets supper hot, hot enough to melt a tirestrap into, doe this sound right? Curt, Jim, anyone that has a idea. The picture is not great because It was taken with a iphone but I think it readable enough

It's really difficult to tell if there's anything wrong. You just need to double check it carefully. I've built this center before and also got it wrong the first time around where when I turn on the volume loud it will shut down my receiver. So I took it all down and rebuilt the crossover. Everything is fine now. Also, I don't think the resistor should be that hot to melt the "tirestrap". Or should I question the material of your strap? :B

Also, it would be easier for others to look at ur crossover if you label everything on your pic.

Al,

[matthew1975]

thanks I will definitly do this, , I wll go ahead and label everything. How much difference will the enclosure make on the sound. It sounds kinda low volume to me, will the enclosure with that? I put a 1 ohm resistor in series with the 8 ohm resistor, nothing is heating up now, but buy doing this what am I doing? Am I makeing any difference or is this helping out with the heat issure. I will label everything, did both pictures make it through, I sent one with for the subs, and the other for the tweeter/mids?

[Jim Holtz]

Hey guys,

Can someone take a crack at deciphering his crossover? I'm terrible at it and get lost every time I try to follow it.

Regarding running loud music through open air drivers... don't! The only thing you accomplish is finding out if an electrical signal passes from one end to the other, not if it's wired correctly. The heat is a tip off that it isn't wired correctly and I'd discourage ever playing drivers without being in an enclosure. The crossover is designed with the drivers in the cabinet and will never sound right with out the enclosure.

Playing drivers loudly with out an enclosure and potentially mis-wired crossover can easily damage drivers.

Sorry for the slow response but my new job is quite demanding and summer yard work has greatly minimized my support time.

Jim

[Jed]

For starters the cap in the woofer circuit isn't connected to ground.

[Jed]

Not sure about the LCR trap connection. Hard to see if it's a wire or a shadow.

[ThomasW]

Glad to help but ......I can't trace the leads do to the poor lighting of the 2nd pic.

If you can't reshoot the pic, use something like MS Paint to draw the circuits you created. Use a different color for each run so they're easy to follow.

[matthew1975]

I know these pictures are horrible one is early of the sug and it is connected for the sub, and the other picture was with a iphone since my wife and family are at the beach with the camera. I will have to try and borrow another camera from some other family member. But thanks for trying to deciper it. I will get better pics up soon, but the sub one is correct if I hook the one into the terminal right? I have already powered up my speakers with it and they all work but the 4 ohm resistor got hot enough to melt a tie strap into, so something isn't right I guess, how hot is this suppose to get. I had it hooked up to a xpa-3 cranked very loud testing it all for about a hour, not sure if that was the reason, but all the speakers work. thanks again

[Jed]

, but the sub one is correct if I hook the one into the terminal right?

Yes-- that cap needs to go into the ground/negative terminal.

[jyqureshi]

Hey Matthew,

I compared only the mid crossover with my center's mid, and it looks correct, unless I don't see something:


You can also compare this to your xover.
One little problem I see is pointed out in your picture here:



if those two in the red circle are shorting then crossover is not working as intended.

Also the output polarity should not change IMHO, see "Still +ve", you just change it when actually connecting the drivers.

Hope this helps.

Edit: The small mid cap should be connected to the ground, but looking at the black out wire, it could be since it's soldered to something.

[Curt C]

:B

I had it hooked up to a xpa-3 cranked very loud testing it all for about a hour,

Since the XPA-3 is capable of 300wpc, I'd say we know why you are melting zipties. :B

It appears you've got everything connected correctly. The wiring should be cleaned up a bit so nothing touches, but otherwise, as near as I can tell, it looks OK. Adding the 1 ohm resistor to the 8 ohm wouldn't have appreciably lowered its power disipation significantly. At typical listening levels the resistors should not get overly hot. I'd suggest mounting them up off the board so they can get some air circulation around them, and don't cover them with stuffing when you mount then in the enclosure.

C

[Jed]

If everything is indeed correct, one thing he might try is to parallel a pair of 8 ohm Mills resistors and replace the single 4 ohm. That will give him more power handling and keep things from melting.

[BOBinGA]

Here is another quick test you can try. Unsolder one end of the resistor that is overheating to get it out of the circuit and measure its resistance. For example, make sure the 8 ohm is truly 8 and not 0.8. If it's 0.8, that's almost a short circuit and you will have lots of current flowing through it. Adding 1.0 ohms to it with another resistor would still be a low resistance, but would not overheat as quickly. Likewise, check the 4.5 ohm resistor and make sure its not .45 ohms.

-Bob

[matthew1975]

Thanks for all the suggestions. I will hopefully have my friends camera tommorrow. Jyqreshi I know you can't tell by those pics but those to wires aren't touching each other, they are about 2 inches apart. Also are you saying I just need to make sure my leads for the speakers are the same or I need to change the outputs for the speakers? Jed the circuit that is overheating is the mids circuit it has a 10, 1, and 8 ohm resistor, the 8 ohm is the only one getting hot. I will take the tie straps off the resistors since the sodder is holding them anyway to get more air, do you think I should parallel two 8 ohm resistors maybe. ThomasW I was wondering how to do that when I get the new pictures I will trace it out. And I won't be cranking it up loud anymore until I finish the enclosure, I am working on that now gonna work on the back side first to get some practice with the router and jig. In the end I was gonna use the xpa-2 to power this instead of the xpa-3 I use that for the surrounds, do you think that the xpa-2 is overkill or should it be fine? thanks for all the feedback hope to have some pictures up soon.

[Jed]

Jed the circuit that is overheating is the mids circuit it has a 10, 1, and 8 ohm resistor, the 8 ohm is the only one getting hot. I will take the tie straps off the resistors since the solder is holding them anywn.

If the 8 ohm resistor is getting hot... parallel a pair of 16 ohm resistors to make the final value of 8 ohms.

[matthew1975]

BoBinGA I tested the 8 ohm resistor before and after it was soldered in it read 8 ohms, hooked up or not. No difference at all in the readings. So could this be the problem? I am gonna get two 16 ohm resistor I think.

[BOBinGA]

Is it 8 ohms with the speaker connected? It should be closer to 4 ohms with the speaker in the circuit. If it's 8 ohms without the speaker, its fine. But in any case, two 16 ohm resistors in parallel should solve the problem.

[matthew1975]

Yep its without the speaker hooked up. I think am gonna go with the 16 ohm resistors.

[jyqureshi]

Matthew,

If you look at this diagram:



The +ve output from the crossover connects to the -ve input of the mid and tweeter drivers. That's all I was pointing out, so in case when you're all ready to install the drivers in the finished cabinet, you don't end up connecting the +ve to the +ve of the mid and tweeter drivers by mistake.

I hope I'm clear this time.

[matthew1975]

Here is a better picture. It will change though since I am gonna add the 16ohm resistors

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[matthew1975]

Try again

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