# Keep blowing tweeters!! Ideas and suggestions, please!



## black_z (Sep 15, 2009)

I built two towers, each using four 5-1/4" mids and 8 tweeters. Here are the tweeters http://www.parts-express.com/goldwood-gt-302-1-2-mylar-dome-tweeter--270-170

Maybe my thinking is off...?? They are supposed to handle 30 watts each, so 8 in each tower should handle 240 watts. Add that to the mids (70 watts times 4 speakers) handling 280, gives me 520 watts per tower. I am running both towers off of one channel of an EP4000 at around 6 ohms. Shouldnt be anywhere near 1000 watts.

I have one of these inline with the tweeters and it audibly cuts out all but high frequencies, but maybe they are still moving enough to blow up? http://www.parts-express.com/dayton-audio-dmpc-22-22uf-250v-polypropylene-capacitor--027-415

Mids handle the power fine, but I am constantly blowing tweeters.

I really like my simple little design, so I'd like to know if I'm doing something wrong. If they are just junk, I'll change the faceplate and go with something else. Thanks for any input!


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## Kal Rubinson (Aug 3, 2006)

black_z said:


> I have one of these inline with the tweeters and it audibly cuts out all but high frequencies, but maybe they are still moving enough to blow up? http://www.parts-express.com/dayton-audio-dmpc-22-22uf-250v-polypropylene-capacitor--027-415


Inadequate device and inadequate information.

It is not completely clear if (1) you have "one of these" inline with each tweeter or only "one of these" inline with the array of tweeters or (2) how you have the tweeters (with or without their caps) wired: series, parallel or series/parallel.

Tell us more.


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## black_z (Sep 15, 2009)

The more I read, the more I realize the less I know! 

I have 1 per tower. The tweeters are wired each side(left/right) in series, then parallel. So, 4 tweeters in series on the left side of tower...4 in series on the right, then both parallel.

That make sense?


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## lcaillo (May 2, 2006)

Where is the cap in this design?


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## black_z (Sep 15, 2009)

1 per tower. On the positive wire going to the parallel wiring of the two sets of 4 tweeters, which are wired in series. That sounds confusing!

So, it's on the positive wire that branches out to the two sets of series wired tweeters. Hope this makes sense!


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## Kal Rubinson (Aug 3, 2006)

black_z said:


> The more I read, the more I realize the less I know!
> 
> I have 1 per tower. The tweeters are wired each side(left/right) in series, then parallel. So, 4 tweeters in series on the left side of tower...4 in series on the right, then both parallel.
> 
> That make sense?


It makes sense and explains your problems. Wiring them as you do with 4 in series (=32ohms) and then the two groups in parallel (=16ohms), your 2.2mf capacitor give you a very gentle 6db/octave high-pass beginning at 4521Hz (according to the math).

Your tweeters are rated at 30w each but without specifying over what frequencies. However, their rated FR (without adequately specifying variation/roll-off) is given as 4000-19,000Hz. As a result, the capacitor is barely having any effective attenuation at the speaker's low end of 4kHz and, in fact, the attenuation is less than 6dB at the speaker's resonant frequency of 2600Hz. It is likely you are driving the tweeters hard into resonance and burning them out.

I would consider a higher and steeper high-pass filter or, perhaps, a better tweeter. How did you decide on matching these drivers? What are the specs for the "mids?"


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## black_z (Sep 15, 2009)

I will admit that 90% of the very little I know about speakers, is about subwoofers.

The speakers were a gift to me...something to get me started into the home theater world. Here are the specs for the mids... http://www.parts-express.com/goldwood-gw-s525-4-5-1-4-poly-cone-woofer-4-ohm--290-301

If I can make this work, by doing a better job with frequency control, I'd like to keep what I have. I like my simple design(colors and spacing and all), and it's crystal clear beyond the point of comfortable listening.


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## Kal Rubinson (Aug 3, 2006)

black_z said:


> I will admit that 90% of the very little I know about speakers, is about subwoofers.
> 
> The speakers were a gift to me...something to get me started into the home theater world. Here are the specs for the mids... http://www.parts-express.com/goldwood-gw-s525-4-5-1-4-poly-cone-woofer-4-ohm--290-301
> 
> If I can make this work, by doing a better job with frequency control, I'd like to keep what I have. I like my simple design(colors and spacing and all), and it's crystal clear beyond the point of comfortable listening.


I am years removed from my speaker-building days (but I do miss them). That said, there are many here who are much more capable of advising you about the specifics. There are simple, generic formulas for calculating/designing crossovers but they are rarely successful.


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## black_z (Sep 15, 2009)

So, even though I'm keeping bass out of them, I could maybe be still yet sending enough movement to be blowing them?


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## Kal Rubinson (Aug 3, 2006)

black_z said:


> So, even though I'm keeping bass out of them, I could maybe be still yet sending enough movement to be blowing them?


Probably.


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## black_z (Sep 15, 2009)

Where do you think I should be crossing them over? What frequency should i try to keep out of them?


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## Kal Rubinson (Aug 3, 2006)

black_z said:


> Where do you think I should be crossing them over? What frequency should i try to keep out of them?


Certainly, you need to keep 2900Hz out of them and that means a higher and steeper crossover. That said, there is no way for me to know what are the frequency responses of these tweeters and these mids and, therefore, cannot predict what the combined FR will be. One needs precise measurements or, at the least, lots more technical information about the drivers.

As I implied earlier, these may not be a suitable match.


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## fbov (Aug 28, 2008)

Let's back up a minute. 
- The spec sheet for these tweeter looks like a fairly flat, 8-Ohm load, but is the spec sheet accurate?
- Are you sure you've got a paralleled pair of 4 tweeters in series?
- and the kicker in all this... how does the speaker sound?

Spec sheets are always to be confirmed, but without an impedence bridge or test rig (PE's DATS), blind faith is the only option. 

The wiring you give is reasonable, but it should also give the tweeters extra protection (assuming the 4 mids are series-parallel wiring, which maintains their 4-Ohm impedence). If it's a 16-Ohm array, per Kal's calculation, the tweeters should see 1/4 the current seen by the 4-Ohm mid arrays. 1/4 the current is 1/4th the voltage drop, -6dB. Since the tweets are ~+3dB more sensitive, the overall impression should be fairly balanced, given you're running the mids full range. 

Conversely, if you got series/paralle backwards, you've got a 4-Ohm tweeter array, which should draw the same current as the full-range mids, and so sound overly bright, as well as exhibiting reduced power handling. 

So, how do they sound? Is it balanced, or overly bright? Note this is primarily trouble-shooting advice, as what you really need is a proper crossover!

Hope this helps,
Frank


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## black_z (Sep 15, 2009)

Kal Rubinson said:


> Certainly, you need to keep 2900Hz out of them and that means a higher and steeper crossover. That said, there is no way for me to know what are the frequency responses of these tweeters and these mids and, therefore, cannot predict what the combined FR will be. One needs precise measurements or, at the least, lots more technical information about the drivers.
> 
> As I implied earlier, these may not be a suitable match.


Wasn't the response listed in the links I gave? If I can just keep them from giving up the ghost, I'll be happy, because I really do like the sound that comes out of the system!



fbov said:


> Let's back up a minute.
> - The spec sheet for these tweeter looks like a fairly flat, 8-Ohm load, but is the spec sheet accurate?
> - Are you sure you've got a paralleled pair of 4 tweeters in series?
> - and the kicker in all this... how does the speaker sound?
> ...


I'm sure they are paralleled pairs of 4s in a series.

Everything sounds amazing(to me and some friends). Pretty balanced(these were a gift from my brother and he researched the different wirings and sensitivities for a balanced sound). Crystal clear beyond the point where you have to squint your eyes, turn your head, and turn the volume down! haha


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## black_z (Sep 15, 2009)

Kal Rubinson said:


> Certainly, you need to keep 2900Hz out of them and that means a higher and steeper crossover.


Yeah, I did a ton of reading today and it seems some successful loudspeaker designers recommend being down 12-15db at Fs. If not 18. I had no idea...


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## Kal Rubinson (Aug 3, 2006)

black_z said:


> Wasn't the response listed in the links I gave?


Nope. Giving a range without any qualifications or without providing a graph is inadequate.


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## black_z (Sep 15, 2009)

Okay. Do you have an example so I'll know what you're talking about?


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## Kal Rubinson (Aug 3, 2006)

black_z said:


> Okay. Do you have an example so I'll know what you're talking about?


Here are two:

https://www.madisoundspeakerstore.c...dax/audax-tw010e1-10-mm-polymer-dome-tweeter/

https://www.madisoundspeakerstore.c...less-pl11wg09-08-premium-line-4.5-mid-woofer/


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## black_z (Sep 15, 2009)

Cool! Never saw that response graph before for a speaker being sold. Thanks!


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## fbov (Aug 28, 2008)

To see if the issue is crossover frequency, try a quick test. Get 2 more 2.2uF caps and connect them in parallel to the ones you've already got. That should roughly double the crossover frequency, leaving a hole in the response if they were flat in the first place (unlikely). If they still blow, you know it's more than just the crossover frequency. If not, I hope you still like their sound!

Have fun,
Frank


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## black_z (Sep 15, 2009)

Shouldn't I maybe just do a 2nd order HPF, instead taking the x-over frequency higher? To prevent a gap in frequencies...


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## Kal Rubinson (Aug 3, 2006)

fbov said:


> To see if the issue is crossover frequency, try a quick test. Get 2 more 2.2uF caps and connect them in parallel to the ones you've already got. That should roughly double the crossover frequency, leaving a hole in the response if they were flat in the first place (unlikely). If they still blow, you know it's more than just the crossover frequency. If not, I hope you still like their sound!
> Frank


Nope. Putting the caps in parallel will increase the capacitance and lower the crossover frequency. If you put them in series, it will raise the frequency.


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## black_z (Sep 15, 2009)

Thanks for clearing that up. What would parallel have been, 1 on each wire?


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## GCG (Aug 22, 2013)

Why has no one mentioned the possibility of clipping on the low end. If the amp is clipping there will be high power, high freq artifacts that would be shunted straight through unfiltered.

So the question I have is what amp are you using and what % output when you blow the drivers?


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## GCG (Aug 22, 2013)

Sorry, I read too quick. All that was in the OP.


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## GCG (Aug 22, 2013)

I'd still want to put a scope on the output.


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## black_z (Sep 15, 2009)

Scope? Sounds like that's above my paygrade!


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## GCG (Aug 22, 2013)

USB Oscilloscopes can be had for under $100 and are easy to use. A low tone in the 200-400 Hz range would show you if clipping is an issue.


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## black_z (Sep 15, 2009)

Could there be clipping even though the EP4000s clip lights arent lighting?


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## black_z (Sep 15, 2009)

Kal Rubinson said:


> It makes sense and explains your problems. Wiring them as you do with 4 in series (=32ohms) and then the two groups in parallel (=16ohms), your 2.2mf capacitor give you a very gentle 6db/octave high-pass beginning at 4521Hz (according to the math).
> 
> Your tweeters are rated at 30w each but without specifying over what frequencies. However, their rated FR (without adequately specifying variation/roll-off) is given as 4000-19,000Hz. As a result, the capacitor is barely having any effective attenuation at the speaker's low end of 4kHz and, in fact, the attenuation is less than 6dB at the speaker's resonant frequency of 2600Hz. It is likely you are driving the tweeters hard into resonance and burning them out.
> 
> I would consider a higher and steeper high-pass filter or, perhaps, a better tweeter. How did you decide on matching these drivers? What are the specs for the "mids?"


I found a graph for them on the link I shared. It seems to show 2100Hz on the graph versus 2600Hz in the listed specs. It goes crazy right there.

http://www.parts-express.com/pedocs/more-info/270-170-goldwood-gt-302-more-info.pdf


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## GCG (Aug 22, 2013)

It would have to be a short lived event. I'd be inclined to say no but I don't know how sensitive their clip circuit is ie. how long the signal has to remain clipped to register on the light.

The point is you're blowing tweeters - plural - (granted at a low cost for replacement). If it's caused by clipping all the crossover mods in the world won't help because the clipped signal produces frequencies above your high pass freq at higher than desired power levels that would be passed straight through. That's why I made the comment. IF you had a scope you could rule it out and move on. How much have you spent on replacements so far? Probably not enough to justify an $80 USB scope.


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## GCG (Aug 22, 2013)

Any way you could sketch up the speakers internal wiring and how they're wired to the amp? It'd go a long way to getting to the bottom of the problem. Also did you list the 5-1/4 mids used anywhere?


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## NBPk402 (Feb 21, 2012)

Is it possible that you are driving the tweeters with too much clean power, and overheating them, just like when a woofer is blown from exceeding the max power for too long?


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## Kal Rubinson (Aug 3, 2006)

black_z said:


> I found a graph for them on the link I shared. It seems to show 2100Hz on the graph versus 2600Hz in the listed specs. It goes crazy right there.
> 
> http://www.parts-express.com/pedocs/more-info/270-170-goldwood-gt-302-more-info.pdf


Thanks but that's a horrible graph. It suggests that, aside from the 2100Hz resonance, there is considerable diaphragm breakup at about 12kHz.


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## black_z (Sep 15, 2009)

Yeah, I'm sure it's a horrible speaker. Being 2 dollars and all!


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## black_z (Sep 15, 2009)

GCG said:


> Any way you could sketch up the speakers internal wiring and how they're wired to the amp? It'd go a long way to getting to the bottom of the problem. Also did you list the 5-1/4 mids used anywhere?


I will. I posted a link to the mids on the first page, I think.


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## Kal Rubinson (Aug 3, 2006)

black_z said:


> Yeah, I'm sure it's a horrible speaker. Being 2 dollars and all!


What you built looks good but these drivers don't deserve your efforts.


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## GCG (Aug 22, 2013)

Kal Rubinson said:


> What you built looks good but these drivers don't deserve your efforts.


+1


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## black_z (Sep 15, 2009)

GCG said:


> Any way you could sketch up the speakers internal wiring and how they're wired to the amp? It'd go a long way to getting to the bottom of the problem. Also did you list the 5-1/4 mids used anywhere?



This is going to look confusing as all get out, but it's simple after you see it a couple times. Poorly done, but I tried lol!

Tweeters are 8ohm, mids are 4ohm...


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## black_z (Sep 15, 2009)

If you have trouble deciphering that mess, just ask me! haha


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## NBPk402 (Feb 21, 2012)

When you are blowing the tweeters... How loud are you listening to them? Are they blowing after an extended listening session? If so you might be giving them more power than they are designed to take at those frequencies for an extended time, and overheating them to the point that they seize up.


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## black_z (Sep 15, 2009)

Very! Honestly, since I have 4 sets of tweeters, I never really notice when a group quit working. Only when they all have. Since each set is wired in series, it only takes 1 blown one to break the circuit. 

If my math is correct, the mids are at 4ohms and the teeeters are 16. Does that mean the tweeters are getting 1/4 the power the mids are getting?


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## NBPk402 (Feb 21, 2012)

black_z said:


> Very! Honestly, since I have 4 sets of tweeters, I never really notice when a group quit working. Only when they all have. Since each set is wired in series, it only takes 1 blown one to break the circuit.
> 
> If my math is correct, the mids are at 4ohms and the teeeters are 16. Does that mean the tweeters are getting 1/4 the power the mids are getting?


I don't know... I would think that it would depend on where they music is in the frequency range. Do you know how much power your amp puts out at 16 ohms (I am thinking it will be considerably less)? If i was doing this... I would make a faceboard for one tweeter, and one midrange, and then hookup the crossover, and see if the tweeter still blows... My reasoning is that the amp will be seeing closer to 8 ohm load. By going this route you can figure out what a single tweeter can actually handle. I am wondering if the high impedance load is causing the amp to clip (possibly the clip indicators don't work under such a high ohms??).


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## black_z (Sep 15, 2009)

Well that's another thing. I have two identical towers running parallel of one channel of the amp, ... again, if my math is correct, that's 1.6ohm load hahaha! 

I never realized that until now. It's putting some power out!


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## NBPk402 (Feb 21, 2012)

black_z said:


> Well that's another thing. I have two identical towers running parallel of one channel of the amp, ... again, if my math is correct, that's 1.6ohm load hahaha!
> 
> I never realized that until now. It's putting some power out!


Does your amp like a 1.6 ohm load? I am wondering if the load is that low if the amp might cause a problem that could blow your tweeters.


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## GCG (Aug 22, 2013)

Unless I read the drawing wrong the mids are wired - two in series then the two series networks are in parallel. Making the total impedance of the mids 4-ohms. In parallel with the 16 ohm final for the tweeters that makes for 3.2. divide that by 2 and, Yup, 1.6 ohms.

That iNuke 6000 isn't rated for less than 4. You won't clip (won't develop enough voltage to do that) but it'll no doubt act wonky. Try wiring the speaker boxes in series for a total of 3.2 ohms but that'll still be in the twitchy range. If you rewire the mids all in series for a total of 16 ohms the total for the box would be 8 ohms and the two boxes would be 4 if wired in parallel. That'd be in spec for the amp.


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## NBPk402 (Feb 21, 2012)

GCG said:


> Unless I read the drawing wrong the mids are wired - two in series then the two series networks are in parallel. Making the total impedance of the mids 4-ohms. In parallel with the 16 ohm final for the tweeters that makes for 3.2. divide that by 2 and, Yup, 1.6 ohms.
> 
> That iNuke 6000 isn't rated for less than 4. You won't clip (won't develop enough voltage to do that) but it'll no doubt act wonky. Try wiring the speaker boxes in series for a total of 3.2 ohms but that'll still be in the twitchy range. If you rewire the mids all in series for a total of 16 ohms the total for the box would be 8 ohms and the two boxes would be 4 if wired in parallel. That'd be in spec for the amp.


By "wonky" does this mean the amp could be sending frequencies that the tweeter can't handle or can't handle at rated tweeter power?


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## GCG (Aug 22, 2013)

For me "wonky" means you can't be sure what it'll do so it's best you don't try. Down that low, outside the design spec envelope that far, I wouldn't bet against it flaking out and sending DC down range. That's extreme, I know, but it's like trying to get cutesy with a grizzly bear - just not advisable and will most likely end badly.

My $.02


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## NBPk402 (Feb 21, 2012)

GCG said:


> For me "wonky" means you can't be sure what it'll do so it's best you don't try. Down that low, outside the design spec envelope that far, I wouldn't bet against it flaking out and sending DC down range. That's extreme, I know, but it's like trying to get cutesy with a grizzly bear - just not advisable and will most likely end badly.
> 
> My $.02


When you mentioned "wonky"... That is exactly what I was thinking could happen (DC current to the tweeters).


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## black_z (Sep 15, 2009)

It's an EP 4000. They are supposedly fine at 2 ohms.


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## NBPk402 (Feb 21, 2012)

black_z said:


> It's an EP 4000. They are supposedly fine at 2 ohms.


But you are at 1.6 ohms, correct? Another thing is the Ohms are usually an average as I recall. It might be 8 ohms at a certain frequency and 4 ohms at another. Where I would think it might be a problem is if you are already at 1.6 ohms, and it might go to a dead short at a certain frequency. :T

If I am wrong please correct me.


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## GCG (Aug 22, 2013)

My mistake, sorry. 

Still I think you'd be better off doing the rewire on the mids. 1.6 ohms is nominal. Full range it could hit lower. Bumping the final up into a more stable range could help till you iron things out. You'd still have 950w RMS to work with 1400 peak, plenty for your boxes as long as you don't try to blow the windows out.


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## black_z (Sep 15, 2009)

Ok. Im going to try to figure out another wiring possibility. Id rather not have the highs be the same load as mids, as theyd be way too loud, right?

And I did look of the ohm wiring/power ratio. Simple as it seems. Twice the ohms, half the power. Quadruple the ohms, quarter if rhe power


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## black_z (Sep 15, 2009)

That being said, IF I'm getting 900 watts out of this thing @ 1.6ohms, that's only about 11 watts going to each tweeter. The other 720 watts is going to the 8 mids(which are handling more than rated power quite nicely!).

I'm going to get the total ohm load in check, then do a second order HPF and see what happens.

A quick way to get the load in check is wire my towers in series, giving a 6.4 ohm load.


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## NBPk402 (Feb 21, 2012)

black_z said:


> That being said, IF I'm getting 900 watts out of this thing @ 1.6ohms, that's only about 11 watts going to each tweeter. The other 720 watts is going to the 8 mids(which are handling more than rated power quite nicely!).


The issue would be that the tweeters may not be able to handle power outside of their range... Which might be happening if your amp is being asked to go down to 1.6 Ohms or less. I think you are on the right track to check the total system Ohms and to possibly re wire to raise the Ohms overall.:T


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## NBPk402 (Feb 21, 2012)

black_z said:


> Ok. Im going to try to figure out another wiring possibility. Id rather not have the highs be the same load as mids, as theyd be way too loud, right?
> 
> And I did look of the ohm wiring/power ratio. Simple as it seems. Twice the ohms, half the power. Quadruple the ohms, quarter if rhe power


I think it would depend on the efficiency of the Tweeters compared to the Mids... If they were to high you could always EQ them lower with a MiniDSP.:T


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## black_z (Sep 15, 2009)

They were originally wire this way to balance it out some.


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## NBPk402 (Feb 21, 2012)

black_z said:


> They were originally wire this way to balance it out some.


Please let us know what happens when you re wire them to get the Ohms up over 2 ohms. :T


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## black_z (Sep 15, 2009)

Will do.

In the meantime, today(almost 2 years later!), I just realized I never checked the dip switches on the back of the EP4000 and I have had the 50hz HPF enabled this whole time! Now I have to rewatch all my movies for the new found low bass haha!! I had always wondered why it seemed to roll off on the low end. 

It's like having a BRAND NEW setup! haha


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## jay_1 (Jul 17, 2011)

I dont know if you are still trying this current design but if you are put this filter on your set of tweeters. This will get them down 20 db at FS, and it takes an ultra steep LR6 rolloff to do that which is what this filter is doing. I cant tell you if the polarity needs to be flipped, and honestly with your speaker I'm not sure it matters. Try it connected to the positive and then try it on the negative and see which one you like


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## AEIOU (May 3, 2011)

ellisr63 said:


> GCG said:
> 
> 
> > For me "wonky" means you can't be sure what it'll do so it's best you don't try. Down that low, outside the design spec envelope that far, I wouldn't bet against it flaking out and sending DC down range. That's extreme, I know, but it's like trying to get cutesy with a grizzly bear - just not advisable and will most likely end badly.
> ...


A capacitor blocks DC, and I'm sure he is using at least one capacitor as a high pass on the tweeters.


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