Resonant Frequency

Thanks for the reply.I have just received an e-mail from Origin Live who state that the effective mass of the Rega RB 250 is unaffected by the mod so it is at 11g as quoted on their website.The Ortofon is an X-5 MC so it has compliance of 13um/mN.Weight is 4.1g.So 11+4.1+1=16.1 and I arrive at 11 hz by calculation? I think that this is o.k.On Vinyl Asylum there is stuff in the archives and some say 12hz is optimal maybe 14hz.There is a page on the site for modding Thorens tables called cartridge/arm matching.Their formula is rf=159/sq root((eff.mass+cart weight+fastener weight)*(compliance))they say 10hz is optimal.I would like to know the current concensus on optimal resonance.stefanl

I see that there is some difference as to what an acceptable figure is.A reply on Vinyl Asylum gave the example of the Goldring cartridge that comes with the MMF 5 having a rf of around 8hz,but said to be o.k.Some on Vinyl Engine believe 10 hz is too low,deriving from the original paper of the '70's,and have said you want a bit of give,to around 12hz and can go to 14hz.So far I have seen a range 8-15hz.In fact a lot of people seem to retreat from the original 10 hz and are justifying combos of 7,8hz because thats where their tables are.Interestingly a Blue Point Special on a Rega RB 250 comes to almost exactly 10hz.Does it sound fantastic or do I notice a slight "grey"tonal colouring?(ha ha)

Have you seen the paper in the Vinyl Engine's archives? "Audible Effects of Mechanical Resonances in Turntables" This was the original paper that started the ball rolling.It was given to AES Covention In New York in 1977 by Poul Ladegaard of Bruel and Kjaer.He is talking about optimum's in the 13-18hz range and elucidates the reasoning for this.Although it is old,it is an oldy but a goody and has sparked a lively discussion.Stefanl

Great to see your post explaining the issues involved janvoorn! I have done some thinking on this and it occurred to me that with the Rega arm for instance,the most popular cartridges for it, that seem to come up time and again on this and other forums, are the Sumiko Blue Point Special and the Dynavector 10x5.I calculated the rf for these and they both come out at almost exactly 10hz.My Ortofon again recommended favourably, is almost exactly 11hz.I read an argument on Vinyl Asylum supporting 8 hz optimum but the reasoning seemed strange,The bass response apparantly sounds too "fat" at 10hz.But this could be a function of the mat or VTA.Preferring a thinner sound is a path many have travelled re.higher volumes and digital sound colouring tastes,esoteric rock etc.,so I am wary.Again the success of the aforementioned cartridges is a strong argument.Stefanl

This is to whet your appetite.On page 14 of the aforementioned paper."Since we have to conclude that practical records contain a large amount of "rubbish" centered around 4-5hz including warps,the optimum solution is clear.The tonearm/cartridge resonance has to be placed at such a high frequency 13-18hz that it mechanically filters out the subsonic signals.In addition some damping should be applied to eliminate oscillations and influence above 20hz" Stefanl

I have tried a little bit of tweaking with Blu-Tac on top of the cartridge on my Ariston arm.Some possible improvement in sound-staging ocurred, but is this the right place to put it.Anyway I was only estimating the arm's effective mass at 23g giving about 9hz resonance.Is this correct? That is the figure Jelco gave me for their "curved" 250 arm and I am using the straight arm which looks very similar.Also I would like to know if you can stay with the recommended tracking-force or play it by ear to start?stefanl

I probably misinterpreted what I was aiming for in the last post,but I thought some added weight might be interesting.I think the straight Jelco arm is possibly much lighter than its "curved" cousin.I would really like to know its effective weight.The experiment failed as it was really too "bassy".What would a Graham 2.2 arm with a Koetsu Urishi mounted in a Linn Sondek sound like?Stefanl

The information for this arm is sparse.I got one line from Jelco saying their new arm was 23 g.That was it.Last time they said they had no records left of the straight arm they produced 20 years ago for the Ariston Q Deck.It was the same arm on the Revolver Rebel and a couple of others about 10 years ago.Someone said they still OEM a straight arm but I haven't seen it.The cartridge is 7g with a rated compliance if 10.If it gets any heavier it is bad,but I figure the straight arm is a few g's lighter.How much? Stefanl