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PostPosted: Sun Feb 25, 2018 4:32 pm 
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I noticed the other day when I pulled the grilles off of my Szabo 424’s while playing at low volume that the drivers (5” frame diameter with rubber surrounds) seemed to move excessively...visually flubby...?
That did not seem like a good thing. They sounded fine but visually disturbing.
Would that be an indication that something is out of phase or could that be normal?
Upon closer inspection it appears that somebody (not me) replaced the surrounds and did not remove the old gasket and rather glued to the top of gasket...and the cone...which on smaller drivers I believe typically glue to the back of the cone.
How messed up are these?
Thinking it’s time for fresh drivers.


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PostPosted: Sun Feb 25, 2018 5:24 pm 
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have you considered maybe its not the speakers but the amp?

honest to jibbers I've never heard the comment " too much woofer movement " !!

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PostPosted: Sun Feb 25, 2018 5:55 pm 
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If you are going to get bass from small speakers, they have to move a lot more than larger speakers.

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PostPosted: Sun Feb 25, 2018 6:05 pm 
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Not sure we are talking about the same thing. I had a problem where the driver sounded fine but was moving so much it looked like it would tear away from the basket. Turned out to be a bad cable between the preamp and amp.


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PostPosted: Sun Feb 25, 2018 6:16 pm 
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BinkyTheCat wrote:
have you considered maybe its not the speakers but the amp?

honest to jibbers I've never heard the comment " too much woofer movement " !!


It’s a Hitachi HA5700 amp...i never really considered that...hmmm? The replacement speakers (Akai mini monitors) seem to act, move and sound “normal”. But I’ll look into it.
Yeah...too much woofer movement... :lol:

-- 26 Feb 2018 02:21 --

Some good food for thought. Thanks guys.
I thought being rear ported they would maybe move less.
Might swap the drivers out anyway just for kicks and shiggles.
I think I’ll look at some X over mods while I’m in there too.

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Last edited by alexander_x on Sun Feb 25, 2018 6:22 pm, edited 1 time in total.

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PostPosted: Sun Feb 25, 2018 6:21 pm 
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For the lack of specific details, does it only happens when you listen to the vinyl? If it does then you have a simple case of subsonic frequency intrusion caused by a combination factor from the turntable and phono stage rumble and noise.


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PostPosted: Sun Feb 25, 2018 7:01 pm 
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tube54 wrote:
For the lack of specific details, does it only happens when you listen to the vinyl? If it does then you have a simple case of subsonic frequency intrusion caused by a combination factor from the turntable and phono stage rumble and noise.


The set up is for 98% vinyl listening. The speaker was sitting literally 2-3” inches beside turntable (due to space constraints). So that would cause that type of reaction? :?
I will relocate the speakers this week and see if that changes anything.
Thnx

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PostPosted: Sun Feb 25, 2018 7:24 pm 
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Too much movement means you reached the resonant freq. of the speaker.
It doesn't show much resistance to the amp at that freq.

Then,
tube54 wrote:
For the lack of specific details, does it only happens when you listen to the vinyl? If it does then you have a simple case of subsonic frequency intrusion caused by a combination factor from the turntable and phono stage rumble and noise.
+1

and
alexander_x wrote:
The set up is for 98% vinyl listening. The speaker was sitting literally 2-3” inches beside turntable (due to space constraints). So that would cause that type of reaction? :?
I will relocate the speakers this week and see if that changes anything.
Thnx
+1

In fact, it could be a combination of both

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PostPosted: Sun Feb 25, 2018 8:16 pm 
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alexander_x wrote:
tube54 wrote:
For the lack of specific details, does it only happens when you listen to the vinyl? If it does then you have a simple case of subsonic frequency intrusion caused by a combination factor from the turntable and phono stage rumble and noise.


The set up is for 98% vinyl listening. The speaker was sitting literally 2-3” inches beside turntable (due to space constraints). So that would cause that type of reaction? :?
I will relocate the speakers this week and see if that changes anything.
Thnx

Sounds like you have an interaction with speakers and TT, could be the arm/cartridge combo might be causing some compliance issues, causing low frequency rumble.
I use a KAB rumble filter..love it
https://www.kabusa.com/frameset.htm?/rf1.htm


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PostPosted: Sun Feb 25, 2018 9:01 pm 
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They are not the original drivers.

They have been re-foamed incorrectly.

Without knowing the X-Max of the driver, you really don't know how far it should move...

Regards
Ohms

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PostPosted: Sun Feb 25, 2018 9:54 pm 
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This is an original driver .The surrounds have probably not been replaced . The bextrene cone were not normally mated to foam surrounds Some were built and rebuilt like this to increase the Xmax . If it were rebuilt the cone was also changed .This build makes it more difficult for the voice coil to slam into the backing plate . A dimpled back plate was a better solution . Some were assembled with the dimpled back plate version of this driver .It is a 4 inch driver . Still a very good speaker and will give an LS35A a good run for the money .


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PostPosted: Mon Feb 26, 2018 3:55 am 
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Its just rumble from the turntable. Use a rumble filter as a previous poster mentioned.


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PostPosted: Mon Feb 26, 2018 10:58 am 
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hardeng wrote:
Its just rumble from the turntable. Use a rumble filter as a previous poster mentioned.


+1

It has got to be rumble. Those speakers being too close to the table and all.

Find a cheap Phono stage that has a switchable subsonic filter. I used to own a Project Phono Box S and that has one.


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PostPosted: Mon Feb 26, 2018 1:44 pm 
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The original drivers (2 versions) look like this.
Attachment:
Szabo 424 One.jpg
Szabo 424 One.jpg [ 28.05 KiB | Viewed 694 times ]


Attachment:
Szabo 424 Two.jpg
Szabo 424 Two.jpg [ 16.23 KiB | Viewed 694 times ]


Regards
Ohms

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PostPosted: Mon Feb 26, 2018 2:03 pm 
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More pics of Szabo's Philips tweeter with dampener . Rubber roll bextrene cone and dimpled backplate . Model train connectors have been replaced with binding posts .AudiOhm versions are early production . John Szabo also had a bigger speaker and a column sub combination stand for the 424"s Sadly he passed in Dec of 2011 .


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Last edited by doctortube on Mon Feb 26, 2018 2:23 pm, edited 1 time in total.
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