I have the Contours and a REL sub in a smallish (11x17) room. My Rega just interacts too much and has feedback with the sub. There is a lack of synergy. That just happens, and there is often no rhyme or reason. Your Dynavector should be just fine. It has a great reputation and sounds great. I've just been unlucky. I'm sure MFP will sort out the issue with it, but I'm ready to move on to something else. When I have more than one or two problems with a subsystem I start to get paranoid about it and question if something is wrong when it isn't. That's when I just switch to something else and call it a day.
Does anybody in the group have the equipment and supplies to do an accurate measurement of tonearm/cartridge measurement? This requires a special LP that has a series of tones that start off at 5 Hz or some low frequency and go to 30 hertz or some higher frequency with each tone lasting long enough for the operator to read off and write down both the readout from the frequency meter and the db or volt meter. One track of tones is vertical modulation and the next track of tones is horizontal modulation. This is what was done in the old B&O turntable clinics. Nowadays with computers I'm sure the entire affair could be done with a single continuous sweep with the output being analyzed, recorded, graphed, and printed out in less than a minute.
The B&O cartridges back then, SP10, SP12, etc., were pleasant, but not state of the art. What made them so popular was that both the tonearm and the suspension system of the B&O turntables were designed for that particular cartridge's mass and compliance. The tonearm's total mass, mass distribution, springiness, and drag were designed so that both the vertical and the horizontal resonance were precisely controlled. Then the suspension resonance, both vertical and horizontal, were tweaked until that resonance was far enough away in frequency, or harmonics of frequency from the tonearm/cartridge resonance such that any external vibration that would affect the tonearm would not be transmitted through the suspension system, and any external vibration that would get through the suspension system would not affect the tonearm/cartridge. This is why you could be playing a record on a B&O and either pound on the table or slam the dust cover shut without the tonearm skipping. It was a fun demonstration. The Bruan turntable had the same ability but via brute strength, rather than elegant design. Since you could put any cartridge you wanted in the Bruan tonearm, Bruan had no way to predict the tonearm/cartridge resonance either horizontal nor vertical. What Braun did was build the suspension system with three (or more?) of their omni-directional oil-damped shock absorbers so the suspension system literally did not have a resonance frequency. I assume the Braun had a variation of the B&O's double unipivot tapered spring suspension, such that any horizontal motion would be translated into vertical motion.
The point being, if some frequency is getting through the floor into the turntable suspension system and into the tonearm, you might be able to short circuit that frequency by altering the amount of mass under the turntable support, changing the stiffness of the floor under the turntable rack/support/table. Another route would be to build a suspension system for the entire turntable, tuned to a different frequency or harmonic than the problem frequency. In a very old house I rented, the floor was such a problem (think about the bridge named Galloping Gertie), the only place that worked was a planter shelf in the bay window, at least in the summer. In winter the windows in the bay window were so drafty, the cartridge would get cold and the compliance of the stylus assembly would stiffen and sound awful. So we built a shelf and attached it firmly to a structural wall, and that worked just fine.
Since putting a cartridge in a tonearm is just a wild guess in terms of what the resonance is going to be, making a suspension system for a turntable, particularly if you copy the B&O's three point multiple axis double unipivot tapered leaf spring so that you only have the vertical axis to worry about, might just make a silk purse out of a sow's ear.
Ken
