HELP AFTER MY MODS, My tweeters are subdued and weak-


So I have a pair of Mirage M1 speakers, I changed the caps in the crossovers to Jantzen Superior Z (for the tweeters) and standard z for the mids and bass.
 
I also changed the internal cabling to Supra Classic 2.5.

First Impressions-  Not burned in yet
The highs are there but really recessed in the background. Theres a song I reference and it has a steel guitar solo, I can bearly hear it through the vocals because its seems recessed so far back.

SO HERES THE QUESTION- Is that a symptom of unburned in cables and or caps, or is that just what Supra cables give you?

When I changed the internal cabling a few years back on the same model speaker, I used DH LABS t14 Silver plated cable, This had the opposite effect, it was super bright and fast, but it smoothed out and the brightness relaxed, leaving a lot of detail but not so much your ears bled.

But here its the opposite, its dull on the top end and the vocals kind of take over and blur out the top end.

idahifi
Another way to go is with bi-polar electrolytics. All caps in parallel add, but in series they divide. Using 2 x 2,200 uF caps in series is the equivalent of a single 1,100uF.

I couldn't find a single bi-polar electrolytic at Parts Express, so I suggest a pair of these:

https://www.parts-express.com/cat/non-polarized-electrolytic-capacitors/1385?N=19844+4294967118+4294...

plus one of these:

https://www.parts-express.com/cat/non-polarized-electrolytic-capacitors/1385?N=19844+4294967118+4294...

Put them in parallel instead of in series. Again, you’ll need to compare the final ESR of the 3 parallel caps to the original serial. I suspect you’ll end up with a much lower ESR and need to adjust.  My guess is your original serial was around 2-6 Ohms of ESR. With 3 parallel, modern bi-polar caps, you'll end up with around half.




Best,

E
So the caps the caps I replaced in c1,c3,c4, were bi polar electrolytics, they say bipolar on the cap. Not sure if that matters or if I mentioned it. 
Btw, all cap in the crossover should be bipolar/non-polarized, therefore the two 2200uf connected back to back.
The negative stripes face each other on the 2200uF's, I'm thinking that's in line with what your saying
Idahifi,

Unless otherwise specified, electrolytics are polar, but crossover caps must all be bi-polar (same as non-polar). :)

You can "cheat" by putting polar caps back-to-back, turning 2 polar into effectively a single non-polar with half the effective capacitance.

Film caps as far as i know are all bi-polar.

The rare exception to this is with battery biased crossovers. Very very rare. :)

Best,


E
Ok,  thanks Sean...again, my argument isn't that ESR doesn't matter, My argument is that it isn't enough to do this.  So, you are saying that you replaced your midrange electrolytics and your tweeters returned? 
To be clear in my own pea brain.
Ok,  I have avoided trying to come off as a know it all.  I don't want to be that way,  nor known to be that way, but I'm going into teaching mode....We are combining some difficult theories with some very elementary basics. 
I'm going to speak only as thought this is a tweeter.  
You have a 6 ohm tweeter and it is too sensitive to match your mid range or 2 way woofer,  The way that most designers handle this is to add an Lpad to match sensitivities,  then properly build a crossover for your 6 ohm tweeter to the woofer or mid.
Another way to do it if conditions are right is to add a 2 ohm resistor... The resistor adds a pad to the tweeter, effectively turning it down and also add resistance so that you can now use an 8 ohm crossover.  So 2 birds are killed with one stone.  In this scenario,  extra resistances reduced the tweeter output and raised its impedance.  
So now,  ESR. l When I build a crossover,  I do compensate for ESR,  but it is more for exact matching crossover points than the bit of gain difference,  even so, I try to match gain correctly also. 
So, when Sean replaced the Electrolytics or any of his current caps,  the replacement caps had lower ESR resistance... The argument being made is that the reason his output is diminished is that the resistance is so far off that it is reducing the output of the tweeter. 
Ok, to start with, the resistance on his new caps are much lower,  what that means is that there is less of a pad,  adding resistance will be helping to reduce the output back to the level of the original caps.... Next,  we discussed the crossover point being changed,  if that happened with the exact same value of caps,  his crossover point would be effectively lowered meaning... So, lower crossover point means more perceived output,  less resistance means more output.  Significantly lowering ESR in theory would make his tweeters louder.  I hope this all makes sense.  Tim 

Tim, my guess is a combination of difference of ESR and those old electrolytic caps dried out and out of specs, so a tester that can check the value of the caps and ESR will give us the answer.
One thing that surprised me was the cables made such a big different ...
@imhififan  ... well, again,  ESR should've had the opposite effect.  The old caps matter, plus his Tara Labs are solid core.  Typically solid core are not as extended on top,  plus those Tara labs have some sort of circuit in them... But overall, you are correct, the Tara Labs should not have made such a big difference, unless there were other problems involved. Solder joint or one of the big caps out of phase or a combination is my best guess.
Idahifi's experience is exactly what I've been talking about. :)

In a 2nd order hp filter, this problem occurs from a combination of:

- Very low DCR in the coil
- Very low ESR in the caps
- Too small a resistor in series with the cap
- The impedance of the next stage higher in Hz.

In the right combination of things, you end up with far too low an impedance in the next stage.

Of course, having a monstrous amp fixes this issue, but you'd be surprised how just a little dip around 3 Ohms or less can do this.

Inexperienced modders get themselves into trouble by trying to get the lowest possible coil DCR and cap ESR without understanding the entire circuit, and bam.

Best for them to only replace series caps. There may be some level shifting but it is more benign.

Best,

E
Actually, @idahifi, that's my other bit of advice.

Restore the original shunt caps and leave it alone. :)


@erik_squires  
Sean,  to make this easy, without driving you crazy,  I believe Eriks last advice is the most sound,  replace the caps except the 2 2200 mic caps,  I suspect that you'll be fine... 


I don't think leaving the old electrolytic caps in place is the solution. First, the jantzens ( when Tara cables not used), sounds far superior than the old caps being used with the Tara cables. So if I was going to throw my hands up , I would keep the jantzens and hunt for cables that didn't give me issue's. I tried those belden 5000 cables and didn't have issues and it sounded pretty good. 

Also this hasn't been driving me crazy, I've learned a lot and have enjoyed the project. 

I'm going to buy that meter test those caps, make sure there all good, and try and buy  resistors that compensate for any disparity. 

And if that does nothing, and I'm ready to give up, then I'll try different cables till I get the sound like I know it's supposed to be. 
That's the plan, but for now I've gotta move, so I'll be on a little break for a week or two
Hi Ida,

I'm not advocating you keep all the old caps. Just the one's in parallel with the drivers. Those "shunt" caps.

So long as you are having a good time and learning new things, have at it.

What you might also enjoy, if you get Room EQ Wizard, is measuring your system impedance with the caps. Also measure the individual driver impedance (in box)

Then you can use something like XSim to simulate most of it and play around with different cap ESR in simulation. This will really help you see what is going on.

Best,

E
Eric, I thought you said that a in series resistor that compensate for the low esr of the film caps would correct the problem. Did I misunderstand?
Sean,  I see that you are going to purchase a meter... The one that  I posted is more of a general speaker builders tool.  It doesn't offer esr ratings,  but it will measure capacitors,  resistors and Inductors all 3. If you aren't worried about speaker design then you can purchase a simple cap meter.  Tim 
I was considering getting both, but I'm not sure if I should measure each cap or the circuit on the board when it comes to est
I was talking with a guy in Cali today Fritz from from Fritz speaker, and it came up, to just put a variable resistor in there and tweek it until it sounds right. I don't know I've got half a mind to just ditch the Tara's and find a cable that works with it.
I'm not able to read carefully, so I may not be understanding correctly, but I think the issue is that Tim hasn't seen this problem before. :)  I have, and I've gone through the modelling. This would be the third or fourth time I've seen this issue in total, and the fix is always "magic." :)

What no one believes until they see it is that the problem caused by the low ESR tends to not affect the section the caps are in, but the next one up. That makes it maddening to trouble shoot. People spend all their time and effort trying to fix the HP tweeter section, but the problem is caused by the mid or woofer section (whichever is next down). In a 3-way, these impedance issues can be compounded.

The issue isn't really whether you use polar or non-polar. It's the total ESR that is playing games with you. Tim is quite right that having 2 caps in series is going to double the ESR, so maybe that one could need an extra 2-4 Ohms.

With a little hacking of a couple of audio cables you can make your own cap measurement jig and use Room EQ Wizard. That will be pretty accurate and cheap.


Best,

E


Eric, could you explain in a little more detail how you would make the jig and where you can get that room eq. Is the room eq in place of the meter measuring esr.
Hi Ida,

I sent you a link which explains all of it. Room EQ Wizard is a free speaker / room measurement software which has been enhanced to also do impedance measurements. This includes speakers, caps and coils.

It has a vibrant following, and you'll need to ask their discussion groups for more answers, but here is the link to the software:

https://www.roomeqwizard.com/

And in particular, here is the description of how to do impedance measurements with it:

https://www.roomeqwizard.com/help/help_en-GB/html/impedancemeasurement.html

But I don't actually use it, I use low-end hobbyist/pro gear instead. Still, this would be among your cheapest options.

Best,

E