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Old 3rd December 2012, 09:34 PM   #11
wendle is offline wendle  Japan
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Hi All. Thanks again for your input.

System7, I think the cabinets might have 1" thick walls from what I have read elsewhere on the internet and 20 lbs per speaker sounds pretty heavy for this size of cabinet to be thin walled (i.e. =lossy). I will not know for sure until I can get inside.

Could be case of insufficient quality sound absorbing material/fill.

There is possibility that corrosion may be affecting the connections as I can see a small amount some surface rust on the metal plates at the back of the cabinet which receives the rods which connect the front to the back faces of the cabinet.

I got to get inside to see! I will post pictures once I do.
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Old 4th December 2012, 03:01 AM   #12
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I have recently replaced the acoustic foam in my Celestion 100 cabinets with Twaron Angel hair to very good effect. I don't know how this stuff compares to the filler in your speakers nor to alternatives like wool, but I suspect it will be worthwhile.
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Old 5th December 2012, 08:57 AM   #13
wendle is offline wendle  Japan
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Quote:
Originally Posted by Robert F View Post
I have recently replaced the acoustic foam in my Celestion 100 cabinets with Twaron Angel hair to very good effect. I don't know how this stuff compares to the filler in your speakers nor to alternatives like wool, but I suspect it will be worthwhile.
Very interesting product:

TWARON Angel Hair

Please elaborate how you applied the product to your speakers and the before and after results.
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Old 21st December 2012, 09:22 AM   #14
wendle is offline wendle  Japan
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Default bolt torque?

I have not yet opened the speakers. I read elsewhere on the internet that the bolts holding the front to the back panel must be at the particular torque but no actual number was given. I did not want to undo the bolts until I figure out the correct torque. Does anyone here have any insight/recommendations?
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Old 21st December 2012, 05:49 PM   #15
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Quote:
Originally Posted by wendle View Post
Very interesting product:

TWARON Angel Hair

Please elaborate how you applied the product to your speakers and the before and after results.
I simply filled each cabinet with 60 gms of Angel Hair -5gms per litre. The speakers were full of acoustic foam. Read my "modifying Celestion 100s" thread on here. The improvement was very worthwhile, in particular the low level resolution of the speakers.
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Old 22nd December 2012, 05:47 AM   #16
system7 is offline system7  United Kingdom
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Quote:
Originally Posted by wendle View Post
I have not yet opened the speakers. I read elsewhere on the internet that the bolts holding the front to the back panel must be at the particular torque but no actual number was given. I did not want to undo the bolts until I figure out the correct torque. Does anyone here have any insight/recommendations?
wendle, you ARE being a bit of a wuss here, if you don't mind me saying it. Good God, just open up the flipping case and just avoid overtightening when you put them back together.

Being soft plastic baffles, they will doubtless bend if you do overtighten, but rough and ready will doubtless do. Now let's get on with it.
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Old 23rd December 2012, 05:47 PM   #17
wendle is offline wendle  Japan
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I undid the bolts which all appeared to be the same tightness - just tight enough to hold the speaker together (i.e. not tight at all).

The only stuffing was a small piece if white synthetic batting placed diagonally from under the rear port to the bottom of the woofer.

The single component crossover is a yellow capacitor, 1" diameter x 1.5" long and zip tied to the back panel.

The gaskets for the front and back panel are made from cardboard.

All wired connections were soldered and shrink wrapped.

I will post pictures soon.

I pulled out the existing batting and replaced with long fiber wool which was placed on the bottom and on the back area below the rear port. The capacitor will be done later. I re-assembled the speaker. One speaker sounded lethargic - oops, I accidentally put an extra chunk of wool fiber. After correcting, I had a short listening before bed. The boxy/nasal sound is pretty much gone and bass response appears to be better (perhaps a drop in midrange output). At very low listening volume, the speakers are now listenable which previously had monotonous drone at the same volume. Further listening to follow.
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Old 24th December 2012, 02:44 AM   #18
wendle is offline wendle  Japan
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Photos:

Plug extractor:
Click the image to open in full size.

10mm bolt head:
Click the image to open in full size.

stuffing:
Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

foam glued to end of port:
Click the image to open in full size.

back of drivers:
Click the image to open in full size.

capacitor:
Click the image to open in full size.
What kind of film capacitor is this? It's a ICW/Clarity Cap SA! with a yellow wrapper.
http://www.tnt-audio.com/accessories/claritycap_e.html


long bolts:
Click the image to open in full size.

long fiber wool:
Click the image to open in full size.

Last edited by wendle; 24th December 2012 at 03:10 AM.
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Old 24th December 2012, 06:03 PM   #19
wendle is offline wendle  Japan
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Quote:
Originally Posted by system7 View Post
wendle, you ARE being a bit of a wuss here, if you don't mind me saying it. Good God, just open up the flipping case and just avoid overtightening when you put them back together.

Being soft plastic baffles, they will doubtless bend if you do overtighten, but rough and ready will doubtless do. Now let's get on with it.
Hi system7, you seem to have forgotten what you said in you post #7:
"Those caps ought to pull off to reveal nuts though they might be threaded themselves. This is apparently a job for a dealer to tighten it all up when stuff comes loose, so there might be a pitfall lurking."

I did notice that the different amounts of torque affect the dynamics of the speaker. More experimentation still required.... Originally I wanted to get the torque back to factory spec, listen to the speakers, change the stuffing, torque back to factor spec, and listen again. That did not happen.

I suppose I am trying to mod the speaker there is no right torque (unless one is trying to bring the speaker to factory spec only).

A did an hour of listening and have some more comments. The bolt torque is approximately the same as they were originally by feel. The speakers have improved immensely. The vocals/midrange no longer punctuates the the sound stage with resonant peaks as before but now much smoother/natural sounding. The speakers are much more dynamic and lively - this one was a surprise. Bass response has improved as well. I am surprised how much lower bass there is now. On some piano solos, the sound board sounds HUGE on the lower notes. The highs did improve from the initial listening when I received the speaker to a point where it was listenable. (I wonder if speakers have to be broken-in again if left is storage to many years). There is still some increased roughness that re-appeared after my mod - perhaps due to the much improved midrange.
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Old 25th December 2012, 08:47 PM   #20
system7 is offline system7  United Kingdom
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I'm usually cautious in suggesting improvements to a speaker that is evidently carefully thought out. The pitfall has become obvious though. The baffle attachment is a bit of a fussy design. Too loose and the bass is wobbly. Too tight and it will flex (or even break) a soft plastic baffle. What you call a pigs breakfast of a design really. 4 bolts isn't enough for any solidity.

I would be looking to add some hardwood battens and fix the front baffle with a dozen screws if it's possible. The back panel could also be solid timber, maybe ply.

Might improve things, might make it worse.

Wouldn't do any harm to add a 47 ohm shunt wirewound resistor to the tweeter though. Robin Marshall had his reasons for having it in his designs.
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