By Jürgen Kraus
Note: this chapter only refers to the measurements by Jürgen and Biodegraded. It was written before everybody else joined. Durwood’s setup is similar but he uses a longer tube coupler: 2.5 cm…we use a 2 cm coupler. Kazi uses an IEC711 coupler, and KopiOkaya several of them.
The graphs displayed here were produced using the REW software (unless indicated otherwise; JK’s rig is depicted above). The measuring coupler was two pieces of plastic tubing on the end of a Dayton iMM-6 microphone. No compensation or smoothing is applied. These measurements should not be directly compared to other measurements except those done on the same device. Nevertheless, Biodegraded’s setup (he did some of the measurements of my earphones before I had my now rig) is identical to mine and our curves show a good match (example) which translates to a good precision (defined as a measure of the reproducibility of the results).
Comparison 1: the Hifi Walker A1 measured on our two rigs.
Comparison 2: the KZ E3M/S3M measured by JK and audiobudget.com
Some people question the validity of (our) raw measurements. But our curves match reasonably well with the ones by other who may use slightly different couplers (different internal volume, shape, and possibly slightly vented), but overall there are enough similarities that having heard something on that a reader would understand the signature on ours. Compare for example his Soundmagic E10c measurement at Headflux.de and ours.
On the other hand, you can only compare compensated curves if the compensation between them is identical (after establishing the validity of the compensation). Therefore, any “massaged” curve should be accompanied by the raw graph.
In summary, nothing wrong with raw graphs.
You find our documentation of our rig setup and measurement process HERE.