Disappointed with speed

[#1]

Those seem strange figures to me.
This is a 29dB line, where expectations would suggest around 16Mbps. If DLM had adjusted the SNRM, or put banding in place, then a low "Data rate" figure should be seen in tandem with a high "Noise Margin" figure. But here the noise figure, at 9, is barely above the expected target of 6.
My rule-of-thumb would say about 500-800kbps for each 3dB. This means the speed/noise figures show the line, with the current conditions, is only capable of around 9Mbps - which is a long way of the 13Mbps you have already managed at some point, and still further off the ambition.
My interpretation of the figures would be that there's a lot of interference on the line at the time those stats were taken. The first steps would normally be to rule out faults in your own wiring (by unplugging the phones, extensions, and using the test socket), your filter (by swapping, but you've tried this), and your router (by swapping). Also try swapping the router lead for a different one.

[#2]

[#3]

[#4]

[#5]

HI JamesM,
Still only seeing a sync rate of 9464k. How is your kit set up at the moment? Could you plug into the test socket so I could run another check?
Jojo

[#6]

[#7]

Hi JamesM,
Yes, please do - though we'll not be able to test until tomorrow now I'm afraid (so if you'd rather leave it where it is and change it later that'd be fine).

[#8]

[#9]

HI JamesM,
I'm presuming you're in the test socket now. I've just ran some checks and your sync is even lower now! Goodness knows what's going on there. Could you try a different filter and maybe a different RJ11(the cable between the router and the filter)? After that the only thing to try is a different router.
Jojo

[#10]

[#11]

I think it is worth pointing out here that the filters are low-pass filters and designed to effectively isolate the telephone(s) from the ADSL signal. The ADSL portion of the filter is a straight-through connection to the plug as all ADSL modems are required to perform their own internal filtering (i.e. removing DC and low frequencies).
Hence, when testing the modem in the test socket - and thus disconnecting all extension wiring and phones from the line - there is no need whatsoever for any filter. Furthermore, they should not be used in order to rule them out (or in) to being the potential cause of any problems. Whilst there may be no filtering performed on the ADSL straight-through connection there are still contact points and flexible wiring inside these filters which can still give rise to problems (as seemingly demonstrated here).
Mathew

[#12]

I think the reason for suggesting connections in the test socket should be via a filter is that most users will have modem cables with RJ11 connectors at both ends. These will not fit the BT socket leaving them stuck. Using a (different) filter solves that problem and also checks for a faulty filter.

[#13]

That's a fair point.
Mathew

[#14]

HI James,
After running some checks I still can't understand why your sync isn't higher. The only thing I can think of now is to try a different router.
Jojo

[#15]