Your testimonial is valued! Thanks. Sharing a bit of empirical exploration into getting the Low Frequency Resonance close to 10 Hz (with non-conclusive results):
-FIRST SCENARIO: Dynavector 17D3 on the SME 309 tonearm.
Its low-frequency sound on music was somewhat soft. Little energy. The LF Resonant Point came in at a high 14 Hz on my SME 309 tonearm, so this seemed a likely area for experimentation.
Sure enough, adding weight to the headshell lowered the resonant point to 11 Hz, and the low-frequency sound on music attained a convincing weight and impact. Perfect results, in my book.
-SECOND SCENARIO: Denon DL-103R on the SME 309 tonearm.
The LF resonance point comes in at 12.+ Hertz. Adding 6 grams to the headshell has little effect on lowering the Resonant Point, close to 11 Hz. And adding 3 more grams (total of 9 additional grams!) did NOT lower the LF Resonance any more. But the extra 3 grams had a very bad effect. Now the bass seems murky, has no impact, and the combination is somewhat unstable, with some oscillation visible. (Of course, the tracking force was adjusted to 2.5 grams in each case!).
Now I use NO added weight with the DL-103R and it sounds the best to me, in comparison with the different stages of added headshell weight.
Clearly non-scientific observations, which suggest unpredictable results. My experiences with these two cartridges lead me to conclude that lowering the LF Resonance closer to 10 Hz will give unpredictable results, and have to be judged case by case.
Some unknown variables seem to be at work here, but I CERTAINLY prefer my 103R WITHOUT the added headshell weights on my tonearm.