I've posted a few threads documenting my restoration of a pair of KEF 104/2s and decided to measure the room response using REQ Wizard. Granted my setup is fairly inaccurate (using my iPhone tethered to my laptop as the microphone), the main objective was to see how these speakers fared in my oddly shaped room.
During the restoration, I clipped the wire in the tweeter that extends from the voice coil to the terminals and soldered a thin wire to bridge break. I measured identical DC resistance between both tweeters and played some test tones and couldn't hear obvious distortion, so proceeded with the repair using the tweeter as is.
After finding high distortion when measuring both speakers, I ran measurements on each one individually and arrived at the following (brown trace at 100% is signal, black trace is relative THD):
Left speaker
Right speaker
There's a dramatic increase in THD at ~2.5 KHz to 10%, which I believe is around the crossover frequency between the midrange drivers and tweeter, on the right speaker only. I didn't track which tweeter was repaired but believe it was the right one based on some visual clues.
Would this sort of behavior be expected for a repair like mine, where the thin metal membrane was worked on with a soldering iron/tweezers? I'd imagine so but curious what others thought before I order a pair of new tweeters. I've ran a few sweeps and this increased distortion is repeatable.
The distortion may be audible to me, but I'm not 100% convinced that I can hear it consistently. I've noticed some distortion while listening but suspected it was the recording.
During the restoration, I clipped the wire in the tweeter that extends from the voice coil to the terminals and soldered a thin wire to bridge break. I measured identical DC resistance between both tweeters and played some test tones and couldn't hear obvious distortion, so proceeded with the repair using the tweeter as is.
After finding high distortion when measuring both speakers, I ran measurements on each one individually and arrived at the following (brown trace at 100% is signal, black trace is relative THD):
Left speaker
Right speaker
There's a dramatic increase in THD at ~2.5 KHz to 10%, which I believe is around the crossover frequency between the midrange drivers and tweeter, on the right speaker only. I didn't track which tweeter was repaired but believe it was the right one based on some visual clues.
Would this sort of behavior be expected for a repair like mine, where the thin metal membrane was worked on with a soldering iron/tweezers? I'd imagine so but curious what others thought before I order a pair of new tweeters. I've ran a few sweeps and this increased distortion is repeatable.
The distortion may be audible to me, but I'm not 100% convinced that I can hear it consistently. I've noticed some distortion while listening but suspected it was the recording.
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