Altec / GPA measurements: 515

[gearfreak]

One thread per driver class seems good for posterity, I'll probably do a 604 thread as well. If better form, we could just post all to this single thread.

Alas, tables are not working. Credit to AllenB for the CODE tag suggestion used below.

In an effort to calculate the missing values, I used the DATS box method, but the values seemed suspect.
I switched to added mass, but will ultimately only use the added mass f(s) to calc the additional parameters with TSPCalculator for a subsequent post.

Added mass was courtesy a $1 Walmart 7" trivet.
The concentric circles and doo-dads came off by hand with a little flexing.
The resulting larger circle and 6 2mmx6mm neo magnets held it from the underside for a total 81 grams added mass.


Altec 515-8G free air parameters and again with +81g added mass:

515-8G          A           A +81g              B           B +81g              C           C +81g          D           D +81g
* f(s)=     37.68 Hz    23.55 Hz            37.68 Hz    23.55 Hz            37.68 Hz    23.55 Hz        38.36 Hz    24.9 Hz
* R(e)=     6.36 Ohms   6.354 Ohms          6.179 Ohms  6.125 Ohms          6.128 Ohms  6.164 Ohms      5.877 Ohms  5.834 Ohms
* Z(max)=   118.9 Ohms  86.07 Ohms          130.7 Ohms  89.25 Ohms          123.8 Ohms  87.85 Ohms      119.7 Ohms  71.89 Ohms
* Q(ms)=    5.331       6.019               6.736       7.137               6.302       6.894           6.517       6.122
* Q(es)=    0.3012      0.4798              0.3343      0.5258              0.3283      0.5202          0.3364      0.5406
* Q(ts)=    0.2851      0.4443              0.3185      0.4897              0.312       0.4837          0.3199      0.4968
* V(as)=
* L(e)=     1.365 mH    1.287 mH            1.23 mH     1.18 mH             1.258 mH    1.248 mH        1.178 mH    1.093 mH
* n(0)=
* SPL=
* M(ms)=
* C(ms)=
* BL= 0
* K(r)=     0.04771     0.05257             0.04849     0.05123             0.04182     0.04456         0.04073     0.04622
* X(r)=     0.5487      0.5396              0.5395      0.534               0.5598      0.5547          0.5548      0.543
* K(i)=     0.009589    0.009553            0.007891    0.00753             0.0112      0.01161         0.008797    0.008206
* X(i)=     0.705       0.7053              0.715       0.7188              0.6925      0.6897          0.7         0.7063

The select values above, from the DATS formatted TXT option.

...but notice that certain values do not jive with when matched with their screencaped counterpart.

e.g.:
515-8A 'A' R(e)= 6.36 Ohms vs 6.374 Ohms

In some cases e.g. L(e) the difference is known: it is the 10k measurement vs 1k measurment.
I can't explain the other discrepancies yet.