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Exrabies 9th January 2013 09:11 AM

Sound changed after speaker restoration
 
3 Attachment(s)
Hi all,

My Emotion speakers (image nicked from the interwebs, but mines are identical) just got a new paint job after almost 20 years of children's abuse :p. I dismantled them beforehand. After putting 'em back together left and right speaker sound rather different. Left is (overly) bright but open. Right is laid back but (a bit) muffled. Used a TEAC amp with low, mid and high controls to check differences, and it's mainly the mids that differ.

Attached pictures show frequency analysis (mono-channel, 1m from floor; 1m from speaker; 30 sec. Norah Jones song). Can anyone give a hint what could have gone wrong. My suspicion is that I put back the damping material differently.

Thanx,

Adam.

phase_accurate 9th January 2013 09:53 AM

It is hard to tell differences by using a recording as a reference (they do differ in the contenet of the channels after all).
The biggest difference I see is in the mid-high crossover area. Are you sure that you reconnected all drivers with correct polarity ?

Regards

Charles

P.S. : This is the wrong sub-forum BTW

Exrabies 9th January 2013 10:05 AM

Charles,

Thanx for the reply.

I picked the 'Loudspeakers/Full range' forum. Is that not the correct one?

The charts are both from the left channel of the CD, and fed into both speakers (one after the other of course). I will check polarity as per your suggestion. A real pain to dismantle 'em again however.

Adam.

wintermute 9th January 2013 10:14 AM

:cop: I've moved to multiway

Pink noise (or a proper mls or sweep) would be best. Also you should really move the speakers so that both measurements are with the speaker and mic in exactly the same spot.

If you get a program like audacity you should be able to create a pink noise file of arbitrary length and burn it to a CD if hooking the computer up is not an option :)

Tony.

Exrabies 9th January 2013 10:33 AM

Hi Tony,

Gotta love this forum (and its members)...

I used Audacity to produce the Freq. picts. Will try some 'real' measurements (square, sine, sweep, pink noise) anyway before taking the speakers apart.

The reason I asked the forum for input is that I HEAR something is wrong. Measurements probably only aid in pinpointing the culprit. Well actually I hoped someone would say "without a doubt it's ... that's causing this" ;-).

Regs,

Adam.

wintermute 9th January 2013 11:53 AM

If you have indeed wired up one of the drivers out of phase, a proper frequency sweep or pink noise test should show it up pretty clearly :) you should see quite a suckout around one of the crossover points! My first ever acoustic measurement (which was done with a very poor quality computer mic) made it very clear I had my mid's wired the wrong way around!!

Tony.

sreten 9th January 2013 12:19 PM

Hi,

As long as you can hear difference swapping of drivers and the like
should pinpoint the problem. Maybe tired capacitors in the x/o.

rgds, sreten.


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