lundi 2 mars 2015

Adam S1X strange noise inside cabinet

I had my Adam S1X serviced last year. Adam replaced everything except the drivers, so new amp modules, new power supply, and shiny new cabinets.



Since I live in China, I had the monitors repaired by the support centre in Beijing. The service was good and the monitors seemed to have been handled with great care (no scuffs etc), BUT I've been getting this resonance/ringing noise issue and I used to think it was my room problem but apparently it isn't.



Today I decided to get to the bottom of this. I did a bunch of tests: swapped the monitors, connected them directly to my Fireface 400 and tested them in different spots around the studio, and at different levels. The noise is coming from inside the cabinets. I can hear it more clearly when I put my ear close to the ventilation holes on the rear panel.



The noise sounds similar to the noise produced by the corner of a piece of paper gently brushing the woofer cone as you play a bass note. Please play attached samples, one is the original (recorded internally) and the other one was recorded using a microphone placed near the back of one of my monitors. It's basically an arpeggiated sine wave. For some reason using an arpeggio exacerbates the noise.



I have checked nothing is clipping, and the listening level is moderate. The noise is not present on neither of any of my three studio headphones.



One of the things I noticed was that when my monitors came back from the repair centre, the white damping material inside the cabinet was not present. The material could be seen from the bass ports, and it looks like cotton. The service centre rep told me that the S1X no longer has the damping material. Can someone kindly have a look at their SX monitors and confirm?



The top pic show my monitor before the repair, you can clearly see generous amounts of the white stuff. The bottom picture is after the repair, no white stuff and you can even see the cabinet wood:











I cannot trust the Chinese rep because he lied to me about several things, so I believe they just forgot to fit it. For example, he first said the S1X design had not changed since I bought mine in 2009, but later he told me the the S1X now does not have the damping material. Also the bass ports lookd different, and the black coating has clearly been re-designed, because the old models peeled at the rear due to heat. The amp module is also different, well at least before the tweeter came on first, then the woofer, with the new amp module it's the other way round. Also he said there was nothing wrong with my amp modules, then why did he suddenly change them and deliberately lied about it until I found out myself after receiving the monitors back (at which point he admitted it).



Could it also be that some wires have not been properly secured and are moving around?




Attached Files Browser does not support the audio player and please download the audio using the link. S1X noise.wav(2.56 MB) Browser does not support the audio player and please download the audio using the link. Internal loopback.wav(4.26 MB)







Adam S1X strange noise inside cabinet

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