Curved and Straight Tonearms


Over the last 40 years I have owned 3 turntables. An entry level Dual from the '70's, a Denon DP-52F (which I still use in my office system) and a Rega P3-24 which I currently use in my main system. All of these turntables have had straight tonearms. I am planning on upgrading my Rega in the near future. Having started my research, I have noticed that some well reviewed turntables have curved 'arms. My question: What are the advantages/disadvantages of each, sonic or otherwise? Thanks for any input. 
ericsch

Showing 4 responses by shadorne

@yogiboy

Good points and a good article marketing the benefits of thin wall - a bit like the benefits of Rega light weight acrylic plinth and platters (in the case of Rega the sympathetic absorption of vinyl vibration is most effective when using an acrylic platter as the material is closer to the properties of the vinyl and like thin walled speakers we are expected to accept the argument that "more vibration" is "better as the material dissipates the energy")

So yes I am aware the thin wall speaker was initially designed for BBC for light weight and portability and then damped with bitumen to reduce the deleterious resonance effects and then the "magical" benefits of more resonance were discovered.

I buy the advantages of portability and light weight. I enjoy the fact my JBL PRX615M are great lightweight PA speakers (light cabinets with light neodymium magnets) that are easy to move around for my band.

However, I don’t buy their resonance arguments. Why use a bitumen damper if the resonance is not a problem? And I don’t accept the claim that the extra cabinet resonance is beneficial - all resonance should be avoided for ultimate fidelity as any resonance will change the timbre of the sound. And thick MDF built heavier speakers can have bitumen damping too - so logically when damped and heavily braced these should be even less resonant than a thin wall.

Of course "beneficial" could be construed not to mean high fidelity but desirable sound to listeners - a warmer tone perhaps or more euphonic sound - I accept that and I agree Harbeth have great mid range tone (it is more the lower frequencies that seem impacted by this thin wall type design - at least to my ear)

My two cents of course. Maybe I just prefer heavier TT and heavy speakers. Certainly you can get great sound from light weight designs: speakers like Harbeth or TT like Rega perform better than very many competive but heavier designs. However the necessary damping required tells me that designers must compensate for the tendency for light materials and thin walls to vibrate with their own characteristic resonances.
@testpilot

Good question. While at it you could ask why are cheap plastic (acrylic) light weight turntables promoted over heavy plinth steel/wood traditional designs?

I think production and shipping cost has something to do with it...not sure if all the marketing hype about better sound is as real and tangible as all the production and shipping cost savings.

Like Harbeth light weight waffling speaker cabinets - I don’t buy into the hype but I do understand how a cheaper build and lowrr packaging and shipping cost is a big competitive advantage...
An S shape has the advantage of resonance reduction. The two bends add rigidity to vibration compared to a straight tube and flexural waves will be attenuated. Also a larger tube is more rigid than a small tube even if they weigh the same (tubes have good rigidity for their mass compared to a solid rod). Light weight straight tone arms have the increased risk of unwanted resonance due to standing resonance waves along the entire length.

Only advantage of straight is they are cheaper to build and can have lower mass for high compliance cartridges.
S shaped arms allow for a greater pivot point distance than a straight arm - so less tracking error....