For the past month I have been listening 009s with increased clamping force from rubber bands looped over the "ARC" (Head Spring). See the attached photos for the rubber bands both on and off the ARC. I have found a tradeoff between a minor decrease in listening comfort (more just a change in the "feel") and substantial improvements in fidelity with tighter clamping. With the four rubberbands shown in the pictures, I hear (e.g., with Krips' Tchaikovsky's 5th on London) more clearly
1) individual lines in the composition incl. esp. secondary lines or subtle accents
2) "groups of individual performers" as opposed to "sections"
3) instrumental "action", i.e., how the components of instruments work together to produce the total sound, e.g., strings, bow and soundboard for violin.
4) hall ambience as distinct from "direct sound" giving a stronger sense of the room in which the performance happened and spatial relationships within that room
5) soundstage openness, i.e., the spaces between performers.
More in the arena of appreciation, the composer's score in all its complexity is more apparent, the instuments are more beautiful, the virtuosity of performers by themselves and in ensemble is more gripping. While they are not my bread and butter, the rubberbands increase my pleasure in listening to e.g., Pink Floyd and Roxy Music, and appreciation for their wonderful music and complex productions.
This all started when, after upgrading to a substantially better phonograph cartridge with less bass bloat: I was consistently missing *something* from the bass. Increased clamping gives the bass satisfyingly more "weight". In repeated ABA tests, I *believe* that there is probably not much more spectral energy at low frequencies. As is well appreciated here, the 009s can go quite low. So, I think that, the energy that is there becomes more "coherent", to give more weight and focus. Double basses are a key player in this drama. When I go back to stock 009s, I can hear the fundamentals from the basses at roughly the same level as through "banded" 009s, but somehow the fundamentals and all the harmonics do not conspire in the same way to produce the impact of bowed or plucked basses. With stock 009s, the basses do produce an indistinct low "humming" and there is some "string sound", but it does not all add up to give the as much weight and impact as with banded 009s. The increase in "coherence" applies all the way up the spectrum, making the sound much "cleaner" and more focused, in terms of both timbres and locations. So, with bands,I hear more clearly where instruments are, and when more than one instrument is playing, I can distinguish notes from each more easily.
I am sort of hoping Tyl glances at this thread and might be moved to see if measurements show any of the audible changes I have mentioned above. I would also be interested in hearing the results of others if they play in this sand box. I have not yet optimised the clamping force: I have not increased the number of rubberbands to the point where either the sound is getting worse or the lack of comfort is simply unbearable. In some ways the change is not all that obvious, e.g., because the overall spectral balance and sonic character of the 009s is not changing all that much. For me this is a "big, subtle" change: even after a month I am amazed at how amazingly good familiar or even new recordings sound. We may have markedly different optimal forces, from listener to listener, as variation in head sizes presumably changes clamping force for even stock 009s; and personal tolerance to clamping force might vary widely. However, for me, with my head size and the rubberbands I happened to find around the house, the musical and emotional value is substantial.
To be precise the Vcc L == Vcc R == 280V and THD is less than 0.5%
