Hmm. The attenuation value should take into account the effect of aluminium.
So, while you will get lower speeds with an aluminium line, you will also get a higher attenuation value compared to the equivalent copper line.
There ya go!
https://onedrive.live.com/redir?resid=3CD50427430923...
Looks to me like the reason for low speeds is more to do with high QLN values.
A really quiet line will be around -140dBm.
I considered my previous line to be "quite quiet", with readings between -120 and -140. I consider my current line to be "quite noisy", with readings about 10dBm lower than yours, across the spectrum (edit: around -130dBm in the ADSL2+ tones, and around -110dBm in the higher tones).
Yours looks pretty noisy to me - and differences like that 10dBm can be worth a lot of speed.
Edited by deleted (Mon 04-Apr-16 14:30:47)