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Old 12th June 2012, 12:39 AM   #251
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There's no need of hate post unless you take this further.
I understand where Alan is coming from and he is only forming an opinion. From what I understand he can later debate that, somebody told him so from what I can guess or read between the lines...
The number two paragraph with the brands was later corrected a few posts after. I can't read anything new, unless there is some scientific data as you mention, to prove either way or about the phrase of the materials (Solen caps) "they are made from they cannot be microphonic" would be of a novel nature to me. Please explain so I can form an opinion. Do you mean a standard manufacturing process with standard materials and tolerances between different brands? Yes, I could believe that.
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Old 12th June 2012, 02:33 AM   #252
sba is offline sba
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There were some closely related threads about microphonics about seven years ago over on the JBL/LansingHeritage site.

IIRC, part of the conclusion was that mounting techniques that reduce vibrations to the caps are a good thing ... and mounting the crossover externally is even better.

I think the Solens actually tested better than a few other film caps.

question arround a mystic microphonic problem in capacitor


Last edited by sba; 12th June 2012 at 02:36 AM.
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Old 16th June 2012, 10:45 PM   #253
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Default a Correction, and a Response to #250 on Page 25, and to others.

CORRECTION: "Chartreaux" is my incorrect spelling of Chateauroux, and as follows:
SCR stands for "Societe des Composants Record", which is a French Company located at Montierchaume,
which is very near to Chateauroux , if this map I have here is correct.
The company manufactures capacitors that are sold under "Solen" and "SCR" brands, and also branded with other names for some other companies.
My initial learning of these capacitors was result of them being refered to as "Chateauroux" by several users of them.
This includes a designer of loudspeakers I met years ago who said he preferred the sound of "Chateauroux capacitors" in his designs to another type we discussed then.
Also, "Chateauroux" was used in at least one reference to these capacitors in a feature article published in "Hi-Fi News" magazine during the 1980s.
Later I became aware that the capacitors being called "Chateauroux" were the from the same manufacturer as "Solen" capacitors.
--- --- --- --- ---

Toppsy,

I am beyond puzzled to almost astounded by your response to my postings,
as apart from the error above, I can not find anything I've written which seems to justify the nature of your response.
I thanked you for the information you posted in your initial response - #245 on Page 25 -
to my earlier post about microphonics in Solen capacitors,
because I thought the information you posted was useful to readers,
and I still do think that.

So far as I understand, this Forum is for members to share information and experience.
That is what I attempt to do.
I do not presume myself to be a "world authority on crossover caps".
I have posted in this thread matters about capacitors for crossovers that I have found in other Audio related Forums ,
in Blogs on enthusiasts' web-sites , in some Magazine articles , in some Manufacturers' information , etc ...
Anyone can do a web-search and find similar and some the same as I found.

Here is a recent updated report of a previous published by the manufacturer of ClarityCaps.
It includes about microphonics:
http://www.partsconnexion.com/t/clar...ch_Summary.pdf
-
The manufacurer of "Solen", etc ... will be aware of research done and reports published by ClarityCap, and in order to compete and keep their customer base they may have improved their manufacturing process since, but I do not know at this time.

What we can do in this Forum is discuss our findings.
That is what you presented in your initial post, and what I and others have done in many posts.
This is what at least some of us will continue to do as more capacitors are tried, etc ...

Regarding your other remark,
Ultimately it does not matter which orifice I am talking through, as long as the information is heard by whom it is directed to.
Of course, if my voice sounds muffled then either I am using poor quality capacitors or inductors, or I do not have the filter tuned well enough.
--- --- --- --- ---

Basically, how caps can be microphonic:
If the tension is not completely evenly mantained across the full width of the two foils whilst the capacitor is being wound,
then regardless of how tightly most of it may be wound,
and regardless of how much epoxy or similar that is applied to both ends of the final rolled component,
there will be inside the capacitor some areas of one foil that are of slightly lesser tension than some areas that are in the opposing foil.
That is, there will in effect be one stiffer charged plate in proximity to one more flexible oppositely charged plate.

A Condenser Microphone has a charged, edge suspended diaphragm vibrating beside an opposite polarity charged fixed plate.
When a vibration is applied to the moveable diaphragm, there is then an alternating difference in Voltage between the diaphragm and the fixed plate as result of the changing electrostatic field between the plates.
That alternating voltage becomes the audio signal.
Thus, even when such as inside a rolled capacitor where the specific roles of each plate are not defined as in a Microphone, so long as one plate is vibrating at a different amplitude to the other in any particular area there will be an alternating voltage generated by the changing electrostatic field there.
This voltage may be small in any single area, but there is a very large amount of area inside capacitors of the capacitance quantities used in crossovers,
thus when a lot of small vibrating areas are summed the final result is sufficient to be audible through the speaker driver connected to the capacitor.
--- --- --- --- ---

Hi Inductor,

I am not gifted with much ability for communicating concise but comprehensive explanations of some phenomena,
but the above about microphonics in rolled capacitors is an attempt.
-

Hi sba,

Thankyou for posting the Link to that test.
I have seen similar published in a technical magazine's article.
{I've forgotten the Title of the magazine, though I probably have the issue with the test somewhere amongst my collected multitude of print items !}
Also, I have seen either similar on another web-site, or perhaps it was that same one that you posted - I have forgotten.
I read so many things that I cannot remember where all the results that I do remember were originally published.
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Last edited by alan-1-b; 16th June 2012 at 10:54 PM. Reason: to add a phrase
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Old 15th September 2012, 06:23 PM   #254
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Default midrange cone driver in Ditton 44

Owners of Celestion 44 ,
I recommend you go to this page:
celestion 66 needs Mid-range
and read Posts #907 <--> 910.

This could benefit the woofers also, and likely the drivers in many vintage loudspeakers, including other Celestion models.

The above are on Page 91 of the Celestion 66 midrange thread, if the Link takes you to another page after more posts move that thread along.
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Last edited by alan-1-b; 15th September 2012 at 06:27 PM. Reason: to add a sentance
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Old 11th November 2012, 03:07 PM   #255
dandoee is offline dandoee  United Kingdom
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hi alan how are you , many thanks for this 25th May 2012, 11:20 post its very clear and helpfull
visited today inspired me to get back on track with my 44 project . i always have one reference 44 not touched , i have been running the pair and need some tweaks on modified ,,
i will post new caps installed and audible feedback , complete and post response chart
but dont have original 44 chart to compare ,?? what always confuses me here is ,(i have 44s but get referenced to 66s so a 66 frq response diagram will be different ? i dont know
all best
dan
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Old 17th November 2012, 07:20 PM   #256
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Default Celestion 44 charts

'ullo dan ,

for original information about Celestion 44 , including parts' lists and schematics ,
go to Page 19 of this thread , and there to #188 by rwtomkins.

I previously referenced you to the hand drawn schematic of the 66 circuit so that you could see where the resistors are to be connected for use with modern polypropylene capacitors.

I do not know where there may be a plot of the frequency response of the 44 , but do not worry about that.

After you install the new capacitors and the resistors , listen to several recordings that you know well ,
and that you think should benefit from the upgrade of the crossover.
Post about those when you are finished and have listened for a while.
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Old 31st December 2012, 02:16 AM   #257
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Good Day!

Well, what started off as a simple job to replace the binding posts in my blackie Celestion Ditton 44s, has turned into a cross-over rebuild project. After the speaker terminals were replaced, I plugged into my amp, and got nothing out of that channel. I have isolated it down to the crossover, I think, as I am measuring 2.7 ohms across the speaker terminals. Hopefully a driver didn't go, but I am doubtful, since I didn't get any sound out of the speaker after I changed the terminals. I've taken pictures and drawn a diagram. The cross-over is the older point to point board.

With New Years just around the corner, it will be a few days before my next post, but it will include pictures.

Happy New Year everyone!
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Old 31st December 2012, 05:27 PM   #258
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Default Pictures

I love these speakers. They sound very sweet, at medium and low volumes. I suspect these are the 50 Watt versions.

The first crossover is my suspected bad unit. I suspect C2. The numbering is based on the designation from another crossover diagram on the Midrange Muddy thread. When I put the ohmmeter on it, it does not behave as a cap should. It also doesn't look too good, which is why I checked it first.

Happy New Year!
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Old 31st December 2012, 06:11 PM   #259
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LOL, too funny! I was just re-reading this thread from the start, and I encountered post 17 on page 2. I totally didn't consider the serial number plaque where the speaker terminals are, and immediately after reading that post I thought, no, it couldn't be. Sure enough, with no cables and the crossover removed from the cabinet, it buzzes continuity.

Well, obviously, I need to replace the caps in the crossover, so I will continue on this project.

Cheers!

Last edited by TechnoDweeb; 31st December 2012 at 06:26 PM. Reason: Corrections
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Old 5th January 2013, 07:49 PM   #260
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Hi TechnoDweeb ,
then it is good that you read from the start of this thread ,
and thus how new owners can find unexpected things when restoring vintage loudspeakers !

Your photos here are useful as they show another version of what can be found inside 44s.
I see some-one installed electrolytic caps in the tweeter filter section - ugh !
The input caps' combination of the midrange filter is visibly different for each of your samples , but may have caps that sum to the same total ,
but if not then check the original schematic posted in this thread.
Really I do not know whether better to use 24uF or 30uF there ,
and it may be better to use whichever was for which of the 2 different versions of the midrange driver that Lucas Adamson posted about in this thread ,
depending on which version you have ...
or use the in-between common value of 27uF , or the 25uF ClarityCap -{see below}.

As you are in Canada there is good choice of capacitors available via Mail-order , such as from:
Parts ConneXion - The authority on hi-fi DIY parts and components
where you can buy AXON True Cap in 36uF to use in parallel pairs to sum to 72uF ,
and the Mills MRA-5 compensating resistors I recommended in this thread.

I recommend you do not use the AXON caps for the midrange and treble ,
but use ClarityCap instead , and if the type Parts Connexion sell are above your price range , then
Madisound Speaker Components: distributor of loudspeaker drivers and parts for speaker builders.
sell the lower priced PX series of ClarityCap which are good enough ,
or find the Sonicap web-site , USA , and buy their own brand via Mail-order ,
plus the Mills MRA-5 resistors.

About your final post in the Celestion 66 midrange thread ,
yes , felt around the tweeter will sweeten up the sound , as it will for the 44.
I will be posting more about felt treatment for front baffle panel in the 66 thread when I have sufficient time available.
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Last edited by alan-1-b; 5th January 2013 at 07:51 PM. Reason: to add a phrase
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