View Full Version : film capacitor help please.
I upgraded the caps in my crossovers from very cheap surplus caps to Obbligato gold caps known to favor upper midrange and the top end for the tweeters.
I chose to use a Clarity cap ESR for a smaller cap that runs in parallel to the larger obbligato and some how reduces the larger caps value.
The Korean/surplus film caps where awful and lacked detail in the upper range of the tweeter.
Now I seem to have loads of details coming through and I love the tone of what I have and acoustic guitars just seem to come alive but I have a couple of recordings that have gone sybilint since the upgrade.
Can a cap have so much affect?
Am I being to picky about this?
I am thinking of changing the obbligatos to Clarity Cap MR,they are 10 uf.
Would this settle down the upper mids and leave the upper details in tact?
Or is a little upper mid range bump a bad thing?
98% of my albums sound fantastic, very smooth presentation so it's not annoying but Jenifer Warrens Famous Blue Rain Coat dose present some sibilance at times.
Should I accept a little sibilance with just a couple of albums for such great blues and jazz presentation?
I mean the texture of brushes on a snare will give you goose bumps.
sq225917
05-01-2012, 08:14
That's the problem with just swapping caps based on their capacitance you can get wildly different sounds. People assume its that's each film cap sounds different but really you've just matched capacitance and not bothered to match ESR as well- so in effect only done half the job.
Effectively it's just like adding or removing a little bit of resistance from the circuit, if you know the ESR for the cap as well as capacitance you can usually predict pretty damn well how one cap will sound vs. another. It's one reason why styrenes and teflons have the rep they do- very low ESR.
...and don't worry about FBR it really is recorded like that with lots of ssssss and ttttttt sibilants
prestonchipfryer
05-01-2012, 09:08
If 98 per cent of your records sound good why worry unduly about the two per cent which have some sibilance. My experience with Janis Ian (Stars) and Joan Armatrading (self-titled) sibilance has only been ameliorated (though not completely) since the introduction of the SME V into my system. On CD the problem of sibilance on these albums is not an issue for me. So it could be that there is mistracking on your set-up.
John :lol:
That's the problem with just swapping caps based on their capacitance you can get wildly different sounds. People assume its that's each film cap sounds different but really you've just matched capacitance and not bothered to match ESR as well- so in effect only done half the job.
Effectively it's just like adding or removing a little bit of resistance from the circuit, if you know the ESR for the cap as well as capacitance you can usually predict pretty damn well how one cap will sound vs. another. It's one reason why styrenes and teflons have the rep they do- very low ESR.
...and don't worry about FBR it really is recorded like that with lots of ssssss and ttttttt sibilants
I felt FBR was recorded right at the edge of being sibililant I used to have it on LP and it was better than CD.
Since then I have gone to all loss less files into a DAC and believe it or not I'm not it's pretty close to a very good turntable and phono stage with out all the hassle of record cleaning,storage and maintenance.
The super tweeters are so good with these caps it really sounds analog,loads of shimmer very much like a Grado gold.
I have listened to several dozen albums since my last post,switching back to FBR to com pair notes.
I believe Famous Blue Rain Coat to be recorded right at the edge of being sibilant with in the recording. If your speakers don't have a slight dip from 3 to 7 khz. or ruler flat your in the sh*t.
Also much like Donovan,NO ONE EVER HAS TO ASK WHAT DID DONOVAN SAY? She has perfectly articulated speech as well as being pitch perfect.
Her tight annunciation leads to a small amount sibilance from my super tweeters or wizzer cone. I can't really tell which one yet, but I have come to the conclusion that the artifact caused by this recording dose not occur with any other recording so I am leaving things as they are.
I am told this recording has always caused sibilance issues since it's first release , Since it is not a sharp or hard sounding problem in only one recording why bother.
It is just slightly less noticeable through my headphones but can be heard on other systems also.
Well.
I am going to remove the 10 uf obblingattos and replace them with Clarity cap ESA caps just to see what happens.
I guess the O caps have a lot of upper mid range and lower treble peak.
Reid Malenfant
07-01-2012, 19:49
I chose to use a Clarity cap ESR for a smaller cap that runs in parallel to the larger obbligato and some how reduces the larger caps value.
:nono: Capacitors in parallel increase the capacitance :)
Are you sure you haven't overcooked it & now have too much capacitance which will lower the crossover frequency of the tweeter but keep the bass/mid unaltered & result in a bit of a peak around the xover.
What value capacitor was originally fitted & what do you have there now to replace it?
:nono: Capacitors in parallel increase the capacitance :)
Are you sure you haven't overcooked it & now have too much capacitance which will lower the crossover frequency of the tweeter but keep the bass/mid unaltered & result in a bit of a peak around the xover.
What value capacitor was originally fitted & what do you have there now to replace it?
I did not change values nor placement in the circuit.
I simply changed manufactures.
The obblangottos did spec at10.36 and 10.39 uf and the factory was at 9.96 and 9.98 uf.
I will request the Clarity caps be at 10.00 uf exactly as I can hear SSSS coming from the wizzer a little but the tweeters a lot.
Mark I promised Eric I would not post pictures of his X over on line,but would love for you to look at a picture and tell me what you think.
Reid Malenfant
07-01-2012, 20:26
I did not change values nor placement in the circuit.
I simply changed manufactures.
The obblangottos did spec at10.36 and 10.39 uf and the factory was at 9.96 and 9.98 uf.
I will request the Clarity caps be at 10.00 uf exactly as I can hear SSSS coming from the wizzer a little but the tweeters a lot.
Mark I promised Eric I would not post pictures of his X over on line,but would love for you to look at a picture and tell me what you think.
Ok so the new ones measure slightly higher ;) That will lower the xover frequency slightly, but maybe not noticeably. The thing is though what value did you parallel them with? What value is the smaller capacitor you mentioned...
I'll PM you my email AD & you can squirt a few pictures to me. I'll in no way post them on line as I respect yours & Erics (who I don't know) wishes :cool:
4.0 or 3.98 uf pictures sent,thank you Mark.
I thought I would be ok as the O caps where with in 5%.
Reid Malenfant
07-01-2012, 20:44
That's it Jeff, your problems are over :eyebrows: The original was 10uf, you changed it to another 10uf that measured 10.39 approx. Putting 4uf in parallel now gives you 14.4uf approximately...
You need to remove that 4uf capacitor as you stuffed the xover frequency good & proper ;)
I'll take a look at the pics shortly chap :)
I had a mall error in the schematic so I sent a corrected one.
But I did not add any more caps or change anything other than brands.
Reid Malenfant
07-01-2012, 21:07
Right, just took a look at the pics :) You had me confused Jeff, well I thought I wasn't but as soon as I saw the wiring diagram I was :lol:
What you have there is a 12Db/octave rolloff to the bass/mid & an 18Db/octave rolloff to the tweeter. I think I understand where you got a little confused which made me ask a question that I didn't need to :eyebrows:
All appears to be in order & your diagram made perfect sense!
Things should be ok as they are, I'd suggest you give things more time to bed in :cool:
Right, just took a look at the pics :) You had me confused Jeff, well I thought I wasn't but as soon as I saw the wiring diagram I was :lol:
What you have there is a 12Db/octave rolloff to the bass/mid & an 18Db/octave rolloff to the tweeter. I think I understand where you got a little confused which made me ask a question that I didn't need to :eyebrows:
All appears to be in order & your diagram made perfect sense!
Things should be ok as they are, I'd suggest you give things more time to bed in :cool:
I have 80 hours on these, And the O caps are known to be bright so I think Clarity MR or ESR will solve my problem,British stuff is never bright or disappointing it was my mistake to go Chinese to begin with. What order X over is this?
I think it's a 3rd order but what do I know?
Reid Malenfant
07-01-2012, 21:19
What order X over is this?
2nd order rolloff from bass/mid & 3rd order rolloff from the tweeter...
In a classic crossover with both sections being second order you'd have the tweeter wired in antiphase to the bass/mid. With your tweeter being a 3rd order rolloff you might try wiring it about face & see what happens. You won't bugger it up as you'll be 90 degrees out either way & you can always change it back. But the thing is one way you'll be 90 degrees lagging & the other you'll be 90 degrees leading, so either way you'll be 90 degrees out, so it might be worth seeing what happens if it's swapped over...
Up to you Jeff ;)
2nd order rolloff from bass/mid & 3rd order rolloff from the tweeter...
In a classic crossover with both sections being second order you'd have the tweeter wired in antiphase to the bass/mid. With your tweeter being a 3rd order rolloff you might try wiring it about face & see what happens. You won't bugger it up as you'll be 90 degrees out either way & you can always change it back. But the thing is one way you'll be 90 degrees lagging & the other you'll be 90 degrees leading, so either way you'll be 90 degrees out, so it might be worth seeing what happens if it's swapped over...
Up to you Jeff ;)
I really wouldn't know what to do there,so I'll just change the 10 uf cap out.
Dose the silver 4 uf cap add 4 uf or take away 4 uf from the 10 uf?
And the 4 uf red caps should not affect the sound as it just shunts the woofer right?
Reid Malenfant
07-01-2012, 21:35
No, they both need to be kept at there respective values! It's a 3rd order rolloff so they will be odd values. They are in series with a choke or inductor if you like acting as a shunt to ground.
If you were going to change the tweeter wiring then simply swap over the positive & negative connections - it's that simple. As I say it'd be easy to change them back again.
Just had a thought. as you have a capacitor feeding the tweeter with no shunt to ground after the 10uf capacitor you could try an old trick :eyebrows: You see with no shunt the whole thing can "ring" a bit... If you get hold of a 47 or 56 ohm resistor of say 6W you could connect this to the end of the 10uf that connects to the tweeter & the other end to ground. This will damp out any oscillation & might get rid of the sibilance while having no real effect on the volume of the tweeter :)
Anything in the woofer circuit will have virtually zero effect on the sibilance you have described, so if the red cap is in that circuit then leave it well alone ;)
No, they both need to be kept at there respective values! It's a 3rd order rolloff so they will be odd values. They are in series with a choke or inductor if you like acting as a shunt to ground.
If you were going to change the tweeter wiring then simply swap over the positive & negative connections - it's that simple. As I say it'd be easy to change them back again.
Just had a thought. as you have a capacitor feeding the tweeter with no shunt to ground after the 10uf capacitor you could try an old trick :eyebrows: You see with no shunt the whole thing can "ring" a bit... If you get hold of a 47 or 56 ohm resistor of say 6W you could connect this to the end of the 10uf that connects to the tweeter & the other end to ground. This will damp out any oscillation & might get rid of the sibilance while having no real effect on the volume of the tweeter :)
Anything in the woofer circuit will have virtually zero effect on the sibilance you have described, so if the red cap is in that circuit then leave it well alone ;)
so together they make 14uf?
I am not going to change the red cap I just wondered if it affected sound to the woofer as a shuntng cap?
I may try swapping the leads at the tweeter.
Do you think I have an oscillation problem or just an overly bright capacitor? As I would have noticed this problem before.
Reid Malenfant
07-01-2012, 21:56
The two capacitors are in series so they'll make less than there combined value ;) There is a choke from the point where the capacitors are connected together going to ground, this is the shunt inductor & helps steepen the rolloff.
However you are still left with a 10uf capacitor feeding the inductive voicecoil of the tweeter & because there is nothing shunting to ground these two can act as a kind of resonant tank circuit. If you wire a highish value resistor (47 - 56 ohms, 5 or 6W) from the output of the 10uf cap & to the other terminal where the tweeter attaches to the PCB you'll damp out the tendency for any ringing & hopefully get rid of any sibilance.
A high value resistor like that will make less than 0.5Db difference to the tweeter output, but probably get rid of what you are describing elsewhere due to damping of a resonant circuit :)
Once again you do not need to worry about the 4uf that shunts the woofer output to ground.
Try the resistor on each speaker before swapping over the connections, I have a feeling it'll sort the problem :)
If you want me to add the resistor position to the diagram you sent me then let me know & I'll fire it back at you :D
The two capacitors are in series so they'll make less than there combined value ;) There is a choke from the point where the capacitors are connected together going to ground, this is the shunt inductor & helps steepen the rolloff.
However you are still left with a 10uf capacitor feeding the inductive voicecoil of the tweeter & because there is nothing shunting to ground these two can act as a kind of resonant tank circuit. If you wire a highish value resistor (47 - 56 ohms, 5 or 6W) from the output of the 10uf cap & to the other terminal where the tweeter attaches to the PCB you'll damp out the tendency for any ringing & hopefully get rid of any sibilance.
A high value resistor like that will make less than 0.5Db difference to the tweeter output, but probably get rid of what you are describing elsewhere due to damping of a resonant circuit :)
Once again you do not need to worry about the 4uf that shunts the woofer output to ground.
Try the resistor on each speaker before swapping over the connections, I have a feeling it'll sort the problem :)
If you want me to add the resistor position to the diagram you sent me then let me know & I'll fire it back at you :D
Yes, please and thank you so much.
If I don't have something to look at I'll mess it up for sure!
As I am learning as i go here.
If the resistor works I'll be tickled pink!
Reid Malenfant
07-01-2012, 22:21
You should have an email Jeff :)
If you are still considering the Clarity MR's, I recommend them without hesitation, amazing caps.
I have not seen your schematic, but are you paralleling a 10 & 4uf to make 14 to hf?
If you are still considering the Clarity MR's, I recommend them without hesitation, amazing caps.
I have not seen your schematic, but are you paralleling a 10 & 4uf to make 14 to hf?
No,they are in series,If this doesn't solve the problem I just might still change the 10 uf cap to a CC/MR but I am not there yet.
The Mark mod works!
I am simply stunned.
I used 50ohm 10 watt sand cast.
It totally did the trick!
I had a hard time as the Xover is not removable so it's like rebuilding a ship in a bottle and to make it harder I both soldered and copper crimped all the connections!
So this time I left off some of the crimp connectors,just in case.
It was not the easiest but it's done.
Mark is the best really!
Reid Malenfant
08-01-2012, 13:51
I didn't expect you to have done it so quickly Jeff :eyebrows: I guess I just didn't think you'd happen to have the right value resistors just laying about..
I took a look at the pictures you emailed & you put them in the correct location, glad it worked out for you, I guess you can now sit back & enjoy the music :)
Yes is worked out fantastic, It's good to have friends I made a call to a buddy who builds amps asked if he knew of a place that sold them locally and he said come on over.
so I stopped and got him a big bottle of his favorite beer. I did some running around for my wife then got home and 2 hours later problem solved.
I was shocked at just how big a difference the Mark Mod made only to the sibilance, everything else seems unaffected. Thank you, Mark !
Reid Malenfant
08-01-2012, 16:46
No worries Jeff, just used my head for once :eyebrows:
All it needed was a bit of damping, the capacitor that directly fed the tweeter through the dropper resistor didn't have anything shunting it so formed a bit of a resonant circuit with the tweeter voicecoil inductance & gave you the sibilance. Damp it with a highish value resistor & you know the rest :)
Mark,How did you learn so much about electronics and Xovers?
I am a tech class ham so at one time I knew some of the basic schematic symbols
and some basic wiring stuff ,mostly forgotten,but Wow! you know this stuff in your sleep!
Reid Malenfant
08-01-2012, 17:12
Self taught, I learnt everything I know now the hard way. I simply wanted to learn so I could make a load of my own kit at the end of the day.
It did get me a load of employment to :eyebrows: It also got me exploited as well unfortunately, no flashy paperwork mean't less wages even though I was doing stuff qualified people didn't appear to know how to :wanker:
Never mind as that's all in the past :D
The speaker designer ran the Mark mod through his speaker modeling software and the mod reduces the output -2 db. from 5.5 khz. to 10 khz.
It pin pointed the problem like a lazor beam, and zapped the ssssssssibilance right where it lived.
A great piece written about sibilance. http://www.homebrewaudio.com/how-to-fix-sibilance-in-your-audio
Well, with some recordings sibilance has been reduced but it would seem some of it still exists 2 examples would be Sheryl Crows C'mon C'mon (soak up the sun)
Surrealistic Pillow (White Rabbit).
Will using a 56 ohm in place of the 50 ohm get me into the 4 khz. range or just reduce tweeter volume a little more than 2 db. from 5.5 khz. to 10 khz.?
Or could it be I just have a sibilant tweeter?
I have even rolled 7 different input tubes in my amp but came back to the Mullards because nothing helped tame the sibilince in some songs although it is far better than it was in other recordings.
I ordered some 51 ohm and 56 ohm Mills 12 watt resisters today to step up the experiment I call the Mark mod.
This is the response graph of the tweeter. http://www.madisound.com/store/manuals/TW025A28.pdf
Reid Malenfant
14-01-2012, 19:11
It'll just cut the volume :(
That may be enough, did you see the numbers on the graph?
What a flight of steep stairs! 104.7 db.! before it gets to 20 K !
Reid Malenfant
14-01-2012, 19:43
Yeah I saw it alraight & with a main resonance at 1KHz to... Must be horn loaded whatever it is :D
Yeah I saw it alraight & with a main resonance at 1KHz to... Must be horn loaded whatever it is :D
Nope.
http://www.madisoundspeakerstore.com/hard-dome-tweeter/audax-tw025a28-gold-dome-tweeter/
Reid Malenfant
14-01-2012, 20:23
Now that's bloody well cheating giving readings at half a metre :lol: Still crazy output for a dome... Have you thought about the rising output as frequency increases may be causing the problem? I mean it wouldn't be too bad if the output was dropping where the tweeter is likely to experience it's first breakup mode, but the opposite is asking for trouble imho :eyebrows:
Now that's bloody well cheating giving readings at half a metre :lol: Still crazy output for a dome... Have you thought about the rising output as frequency increases may be causing the problem? I mean it wouldn't be too bad if the output was dropping where the tweeter is likely to experience it's first breakup mode, but the opposite is asking for trouble imho :eyebrows:
Well, I had some time today so I tried my headphones and found that there is a little sibilance in the same recordings but just a hair more in the speakers so I am going to try a Mills 51 ohm resister and call it good.
I still have some Mills 56 ohm resistors coming and may try that but I have already reduced output by 2db. from 5.5 khz. to 10 khz. with the 50 ohm try.
Reid Malenfant
14-01-2012, 20:44
The higher resistance resistors will increase the tweeter volume slightly, but probably not noticeably :) But then again they'll have far less inductance so unlike the wirewound may well reduce the output at higher frequencies as well as they do at lower ones. The inductive nature of the wirewound sandcast res you fitted will work well at lower frequencies but will have increased impedance as the frequency rises due to the inductance.
Should be good I reckon :) 51 ohms should be the kiddy :eyebrows:
The higher resistance resistors will increase the tweeter volume slightly, but probably not noticeably :) But then again they'll have far less inductance so unlike the wirewound may well reduce the output at higher frequencies as well as they do at lower ones. The inductive nature of the wirewound sandcast res you fitted will work well at lower frequencies but will have increased impedance as the frequency rises due to the inductance.
Should be good I reckon :) 51 ohms should be the kiddy :eyebrows:
The higher resistors will increase the tweeter volume ?
Reid Malenfant
14-01-2012, 21:02
The higher resistors will increase the tweeter volume ?
Yes & no.... 51 ohms will make virually no difference at all to 50 ohms ok? :)
But because you fitted those 10W wirewound resistors that have inductance the wirewounds will increase in resistance the higher the frequency goes. Making them less effective!
A non inductive resistor will not have this effect & will stay the same resistance to frequencies you'll never hear :eyebrows:
So a non inductive resistor will do a better job is what I'm saying.
ok.
i think i actually get it.
thanks. Jeff
Maybe part of the problem is the singer is actually sibilant?
The thing is a spike in the upper mids just makes a small problem worse.
So maybe it's both?
http://www.youtube.com/watch?v=WANNqr-vcx0
I am going to make some big changes the obblingattos will be swapped for clarity cap ESR 10uf ,I like these caps because they are dead flat and don't have any artifacts.
Im changing all the inducers to 14 awg. copper foil Alfa Core. http://www.soniccraft.com/products/inductors/alphacore_inductors.htm
All mills resisters, and all Clarity cap ESR. All internal wire will remain Audison silver/Sounas.
I can't think of much else to improve and I think the O.G. cap is resonating and causing pronounced SSSS and T's as the problem became very noticeable after swapping them in.
I am also going to try swapping the 50 ohm. to a 47 ohm resister to shunt the tweeter during the complete rebuild.
When finished I will smug them with burning sage, sprinkle holy water over them and read the roman ritual of exorcism (older version) and command in all that is holy "evil sibilance go back to hence you came!" I am also looking into a voodoo priestess who has a thing for chicken sacrifice just to be sure.
Reid Malenfant
18-01-2012, 19:06
Dont change any of the inductors unless you get ones with exactly the same DC resistance, or you'll bugger it up :doh:
Dont change any of the inductors unless you get ones with exactly the same DC resistance, or you'll bugger it up :doh:
I got the inductance values from the builder.
Did you get my progression of schematics pictures.
I went back to my electronics books and did some self teaching.:lol:
Reid Malenfant
18-01-2012, 19:38
Did you get the DC resistance of the inductors from the builder to? If not then don't bother changing them ;)
I do appear to remember some odd stuff in my email this morning, yes :D
Inductors are non directional right but is there any difference sonicly by going from the inner to the outer in any direction ?
Reid Malenfant
18-01-2012, 19:39
No difference, just make sure that they are all mounted so that the iron cores are 90 degrees from each other to reduce interactions :cool:
I just talked to the designer and as long as the DC resistance is lower I'm good and it is much lower.
They are not iron core but copper foil.
So but I will still mount them 90 degrees apart.
Reid Malenfant
18-01-2012, 20:51
Do what you will...
The DC resistance of the inductor feeding the bass unit tends to increase the total Q of the bass speaker in the enclosure, by fitting a lower DC resistance inductor you'll lower the total box Q & get a drier bass (read less of it). If that's what you want then go ahead. If you want the bass to stay at the same general level then don't change the inductors - you have been warned :ner:
order canceled ! Thanks, Mark
As soon as my 2 Clarity Cap ESA 10UF / 630V caps get here,I'll remove my Xovers again and see if C.C.ESA's will loose the sibilance with no shunt resister in place,I think getting rid of the Obblingatto Gold caps may be enough.
While in there I will replace the 2 sand cast with Mills resisters then if I still have a problem I can roll a 47,51 and 56 ohm till it's all good.Cool Resister rolling!
Funny they come in 2 colors but they are all Mills 12 watt.
Wow! I just measured them and when they say with in 1% they really mean it.
To get all the values I had to order from 2 different places,but I found a place that has all values now. Sonicraft There is alot of $$$ here.
A strange thing happened today, I have been letting my speakers run alot over the last couple of weeks and today I put on a very familiar recording and noticed the top end had really recessed. So I removed the shunt resisters. Between that and leveling the speakers that I had tipped back before the problem of sibilance seems to have gone.
It would seem just tipping them back 3 to 5 degrees raises the response of the tweeter by up to 3 db. Who would have thought? So after more break in and lowering them back to dead level with the floor all seems well in the world for now.
Reid Malenfant
22-01-2012, 23:34
That is typical of a two way speaker due to the crossover redirecting the response downwards at the crossover frequency due to the phase difference in the distance of the two voicecoils (bass/mid & tweeter) between the speaker & the listener :)
One reason why MTM works so well :eyebrows:
That is typical of a two way speaker due to the crossover redirecting the response downwards at the crossover frequency due to the phase difference in the distance of the two voicecoils (bass/mid & tweeter) between the speaker & the listener :)
One reason why MTM works so well :eyebrows:
Im sure the tweeter position had something to do with this.
This may be my next speaker in a year or so. Any better? http://www.tektondesign.com/pendragon.html
Reid Malenfant
23-01-2012, 15:45
It'll do the opposite & direct it in an upwards lobe at the crossover frequency. It's simply down to the difference in distance between the two voicecoils. If they were the same distance from the front baffle then there would be no up or down lobe.
As I say, this is why MTM speakers work better as with a bass/midrange either side of the tweeter there should be lobes going both ways, or if you like to look at it like this no lobes at all due to them being cancelled by the configuration of drivers.
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