It is a little better for the SDM 3065X, mixed up two readings , its now 0,14%, but still not the value of the GDM-9061. Yes, took the frequency 10Hz-20kHz. Problem here is that 2.200.000 is not better than 1.200.000. Both have as second digit a "2", a "7" won't fit. So both "2" will be zero and the first "0" will be used for the first "7". So in both dmm's you have 5 figures for the actual measurement. As Siglent has a range of 2 the error for correction of range will also be double. The GwInstek has a range of 1 and does profit in this way because the error for correction of range is only single. Yes, I took 1 year spec (I don't call it worst) because that will be more realistic for the hobbyist. If you want 90days then remember that all calculations has to be done same way. I don't advice 24hours, you never get your instrument 24 hours after calibrating. Nice for advertising. There is an other thing which can be found as "loading errors". GwInstek stays 10MOhm, but the Siglent has with 10kHz already an input resistance of 160kOhm (page 92). This can add up to the total error. Have to work out what it will do with other known audio levels.
I was just confused by math.. that is all.. Thanks for responding.
2.200 000 is not better than 1.200 000 but different. At 0dBµV GW Instek will have slightly better guaranteed accuracy. At 6dBµV it will have to range one range up and will lose a digit.. In which case Siglent will be better..
It is highly important where on the scale do you measure. You could do a better job with a 5.5 digit meter in "happy range" than 6.5 digit meter that has to range up..
For instance, when measuring 12V car electronics (8 -18V range), meters with 20V range will do better for that range, not to mention, that relative measurements are much more accurate in single range. For relative measurements in single range, you can use 24H specs.
As for GW Instek "staying 10 MΩ" are you sure about that?
Pure resistive 10 MΩ ?
GW Instek Manual states 1MΩ//100pF... that's 157 something kΩ |Z| at 10kHz ..... page 373