General question on Carbon fiber tonearms versus aluminum

It is not necessarily the material but the execution of the material that defines the performance. Straight aluminum, tapered aluminum, stepped aluminum, foam injected aluminium etc etc.   

Another thought is aluminum may sound better with MM cartridges and CF with MC cartridges.

@slaw Why would one material sound better with MC cartridges than MM?  

@testpilot Agreed, although  I was thinking more in general terms.  That is, it could be easier to make a better sounding tonearm with CF than AL.  Clearly, it is that way with bicycle frames, it is far, far easier to make a frame stiff in one direction and flexible in another with CF, or make it a more comfortable ride with less vibration than say AL or even steel.   

I'm not sure that either aluminum or carbon fiber is inherently better than the other, but magnesium is certainly one of the best materials for a pickup arm - such as is used by SME and Technics on some of their arms.

Clearly, it is that way with bicycle frames, it is far, far easier to make a frame stiff in one direction and flexible in another with CF, or make it a more comfortable ride with less vibration than say AL or even steel.  

Not exactly apples to apples...

You might want to look at this video:
https://www.youtube.com/watch?v=Lb4ktAbmr_4

Since this is only a matter of opinion, I would offer my opinion that I have not found most carbon fiber pieces to be good for verisimilitude in my audio systems. In particular, that has been true of the very few carbon fiber tonearms I have heard. They have tended to produce a sound that seems overdamped, lacking in dynamics. However, they have tended to cover up certain kinds of flaws in certain LPs, and make them sound “good”. But not great.

First post from testpilot gets it right. Carbon fiber done right will beat aluminum done right. The inherent vibration control properties of carbon fiber are simply superior. The key however is to do it right. Carbon fiber fabrication has been around a while now but still nowhere near as long as aluminum. This gives aluminum a big edge in terms of cost of manufacture. At the very leading edge of the high end of course both (all) are pushing the envelope so hard it is all new manufacture. 

That said, take a very successful, accomplished and long history company like Origin Live. They made aluminum tubes for a very long time. When they upgrade models what do they use? Carbon fiber.  

I can make stuff in my shop out of carbon fiber. Got everything you need. Everything except the skill, experience, knowledge, and ability. I can make it- have made it - but not at the level anywhere near professional products. A good example of how you cannot say that something is better simply because it is carbon fiber. It sure could be. But as usual, only one way to know for sure: go and listen. You will see.

Any carbon arm I ever listened to was sounding clinical and boring at the end of day. I know all the conversations about it but I never heard any sonic advantage compared to other regular arms. Even getting them for free I would not listen with those. But, each his own.

To the technical people: What roles do material hardness and strength play when it comes to tonearm material? If I am correct, carbon fiber is stronger than yet not as hard as aluminum; aluminum is harder than but not as strong as carbon fiber.

I have only tried aluminum and titanium nitride arms, so can't comment on the comparison between aluminum and carbon fiber.

I think the comparison between CF cantilevers and aluminum tube cantilevers is a valid illustration here. CF damps more, so has a more smooth, but dead sound compared to aluminum. I don’t care for CF canti’s..

Ive found the same to be true for tonearms. There is a certain muting of dynamics from CF tonearms.

My best tonearm is a titanium tapered tube. Don’t care for magnesium. I would LOVE to finish my new Boron Carbide tonearm soon. I think that will be a winner.

Carbon fiber definitely sounds better on odd days of the month, and aluminum on even days.  This is especially true when you hear the tonearm installed on a turntable you don't own yourself, with  a cartridge you've never heard before, and played through electronics that are new to you.  The best way to get an accurate comparison on material performance!

We do every thing we can to insure that the only movement/vibration that occurs is the tiny magnet or coil within the cartridge.

This transcends throughout the system all the way to the cantilever material: less weight, higher stiffness best.

Tonearms with maximum stiffness: Carbon easily wins over aluminum, it’s calculated differences are shown here:

https://dragonplate.com/carbon-fiber-vs-aluminum

Carbon is -40% density; +70% specific stiffness +289% specific tensile strength.

To achieve a total tonearm weight, to meet a design goal, carbon can be thicker. In any material, thickness increases strength.

My 12.5" effective length arm is Carbon, and the designer can use a greater thickness to achieve his design goal. So, carbon in equal thickness is much stiffer, increase it’s thickness, it is extremely stiffer.

Carbon is the viagra of tonearms.

Looked at the other way, to keep weight down, aluminum must be thinner, thus weaker, thus less damping, less attenuation of vibration.

Pro-ject uses a combination of carbon fiber and aluminum in some of their arms, although the 9cc is full carbon fiber. Linn used the arm on their majik turntable model, so they must think its a pretty good arm. Same arm on my music hall mmf-7.3. My other table is the pro-ject the classic sb with the combo CF/Aluminum 9 inch arm, I honestly hear no difference in sound quality. In my opinion, both pro-ject and music hall provide the most value for one's money today, unless you are rich and splurge for a 10k or more table. They have been very well reviewed in countless periodicals. 

Had Infinity Black Widow which is carbon fiber now i have TW ACUSTIC 10.5 which has better bass,midrange,depth,detail and dynamics.

Note that I and several other very experienced listeners have independently come to the same conclusion regarding carbon fiber in the vinyl reproduction path. It tends to kill the liveness of real music. Theories involving stiffness, hardness, compliance, damping, and blah blah blah are meaningless compared to actually listening to music. Theory is useful after the fact, to explain what you thought you heard.

I too had an Infinity Black Widow CF tonearm.  It was by far my least favorite of the tonearms I have had over the years.  Always seemed rather lifeless, dull, lacking dynamics.  Others have said the opposite about that same tonearm.  It all depends on so many variables, beginning with pairing the cartridge.  For me, it sat for years, barely every using it. I bought it when new, somewhere around 1981.  It initially sold for $250 and I got it for $125 (industry accommodation deal).  I sold it last year for $550.  I hope the new owner enjoys it greatly.

Theory before the fact CAN move the ball forward faster, vs. endless random wandering.....but of course, listening is essential 

I believe it would be a massive system engineering error to consider the tone arm in isolation....in a sense like letting the junior engineer paste a CF wing on an aluminum airplane.....

back to the music....

In particular, that has been true of the very few carbon fiber tonearms I have heard. They have tended to produce a sound that seems overdamped, lacking in dynamics.

@lewm I have both and the CF one is way less dynamic, less detailed, slower, and ultimately less musical than the aluminum ones. But it does have a taller and more expansive soundstage. I found the same thing with a Yamamoto CF headshell.

Thanks for mentioning the Yamamoto CF headshell.  I own two of them and also an Oyaide CF headshell, and guess what; I like them all very much.  Go figure.  Very neutral sounding, and they do not color the sound in the way I hear CF tonearms do.  Another listener might hear these things quite differently, and I do not mean to sound dogmatic. I am only answering for myself.  To add to it, one of the Sonus Faber speakers, or maybe more than one model, is/are made of CF.  To me they have the same character as that which is imparted by the CF tonearms that I have heard, "overdamped" is one way to say it.  But that character is to some degree present in other SF speakers I have heard, with wood cabinets.  So hard to tell what is going on.

@lewm I compared the CF headshell with my standard magnesium one and, while bass was better on the CF, it lost absolute detail—diminishing the color of brass, for example—and "dried" out the "air."

1+ @elliottbnewcombjr. Theoretically, a carbon are can be made stiffer, without the need for more damping materials and most importantly lighter.
Lighter, shorter tonearms with more compliant cartridges sound better. They have a much lower polar moment of inertia. This allows the arm to better follow low frequency undulations in the vinyl lowering distortion. My guess is this is why Michael Fremer prefers a shorter arm and why some tonearm manufacturers like Schroder go out of their way to reduce mass while trying to maintain a stiff arm. This is the reason behind his minimalist " head shell" design. As for which one sounds better? I have no idea. I will find out as I have a Schroder CB waiting for a turntable. I suspect they can both sound excellent given proper design.

This has been a very interesting and enlightening post.  Earlier when I made a comment about bicycle frames, a lot of what was mentioned in this post echo's what folks have found comparing frames made of steel, aluminum, and carbon fiber.   Granted, early fiber bicycles were not as good as steel or aluminum and had a tendency to crack and break, but over a ten year period, it is hard to beat fiber today for a  comfortable ride, yet still have a frame that climbs like aluminum, and is non fatiguing like steel.   With carbon, the vibrations that come up from the pavement dissipate (think damped) and don't tire your legs, arms, and butt like aluminum.  But climbing hills, the last thing you want is a soft frame as what little horsepower you develop goes into making the frame bend rather than to the rear wheel.   Try riding 100-120 miles in a day, climb 10 to 12,000 vertical feet, and do it in high altitude and this lesson will be branded in your brain.   That was my basic training ride back when I did extreme endurance  cycling.

This is pure speculation on my part, but it is possible that the live sound from aluminum, if indeed  it is from the arm itself, could be energy from the cartridge that is causing the arm to color the sound in a rather pleasing way.   The dead sound from fiber, if indeed it is from the arm itself, could be the lack of this coloration.  If you remember, Ray Dolby had the same problem selling his Dolby Noise Reduction to tape manufacturers.   That subtle lack of noise and distortion in the upper frequencies were considered a lack of "air" and consequently colored the sound in a bad way.  He had a real problem for a while until folks realized what he was selling was a lack of coloration and distortion.

Frankly, I don't know which technology is better.   The best sound I had was from my aluminum Grado arm and top tier Grado cartridges.   The carbon arm got the second rate cartridges.   Recently, I upgraded cartridges and now that carbon arm is producing the finest sound my stereo has ever produced.   The Grado setup sounds great and I would be very happy with it, indeed it is better than ever, but I do have that carbon setup right next to it and it beats Grado in a noticeable way.   

It is a tough call since I'd like to upgrade my arm to a modern, transcription length unit.

Clearly execution matters, but if we know what it takes to make a great tone arm, then this question is answerable. Carbon fiber simply has more strength and stiffness as aluminum at the same weight. If that’s what it takes, then yes. But I expect it’s not that cut and dried. There’s got to be cartridge-arm interplay, so I’ll bet it just depends on getting a match. Like the bicycle frame example. The most comfortable is steel. It flexes. Riding cross-country 100 miles a day day after day? I’ll take steel. Racing around an oval for 60 seconds? Probably carbon. Want an 11-inch tone arm that accommodates a “heavy” cartridge? Ask an engineer, but it’s great to have the options we do. The first time an aerospace engineer handed me an early carbon fiber rod and its titanium (or whatever metal it was ) counterpart, I was flabbergasted. And it was a rotor control rod on a helicopter! It goes, the helicopter goes (down). Yet the carbon rod weighed, I don’t know, ounces vs. pounds. It was that dramatic. Amazing stuff.

That subtle lack of noise and distortion in the upper frequencies were considered a lack of "air" and consequently colored the sound in a bad way.  

This isn't the same as acoustic ringing or damping. Dolby effectively filtered frequencies (-3 dB at 600 Hz/ -6 dB at 1.2 kHz/ -8 dB at 2.4 kHz/ -10 dB at 5 kHz) resulting in a removal of ambient information. Back in the 80s, we never used Dolby B or C as both sounded worse than the clear and airy unadulterated sound—albeit with tape noise.

it is possible that the live sound from aluminum, if indeed  it is from the arm itself, could be energy from the cartridge that is causing the arm to color the sound in a rather pleasing way.  The dead sound from fiber, if indeed it is from the arm itself, could be the lack of this coloration.

I'll take the live sound any day for it's pleasing nature over the dead sound of possible lack of coloration. 

noromance

Dolby effectively filtered frequencies (-3 dB at 600 Hz/ -6 dB at 1.2 kHz/ -8 dB at 2.4 kHz/ -10 dB at 5 kHz) resulting in a removal of ambient information. Back in the 80s, we never used Dolby B or C as both sounded worse than the clear and airy unadulterated sound—albeit with tape noise.

Dolby NR does not "filter" frequencies and the result after NR is essentially flat when the system is properly aligned. That requires precise adjustment of Dolby level and bias/eq for the specific tape being used. The prevalence of cheap cassette decks and lazy or misinformed users contributed to Dolby getting a bad rap for filtering highs, which obviously remains to this day. But it is really unwarranted. Both Dolby B and C remain very, very effective when properly used. I still have an outboard Nakamichi NR-200 and on the rare occasion that I play a cassette I'm amazed at the fidelity of mix tapes I made decades ago.

@cleeds Thanks for pointing that out.  The Dolby equalization curve concept is no different than the RIAA concept we all live with when we play vinyl.  There is a Dolby pre-equalization of the music and a post equalization when playing, which reduces hiss.   RIAA pre-equalization and post equalization reduces surface noise.   

Since I wrote that first post, I realized I forgot about Titanium.  My first high end tonearm, a SME III, had a titanium tube, as do several tonearms today.   So, we have Carbon Fiber, Aluminum, and Titanium to consider as tonearm materials which can influence sound.

spatialking

... The Dolby equalization curve concept is no different than the RIAA concept we all live with when we play vinyl. There is a Dolby pre-equalization of the music and a post equalization when playing, which reduces hiss ...

Dolby and RIAA are similar but different. RIAA is an EQ curve while Dolby is a sliding band compression/expansion system. It's that sliding band that makes alignment to Dolby reference level so critical to Dolby working properly.