[tonyptony]

I recently got back my rewired and rebuilt Akito Mk.2 from Audio Origami (great work, BTW). I installed it on my hot rodded ES-1 and mounted my MIDAS'ed 103R. I normally set the arm and cart so the whole thing is dead level; I did that and listened for quite a while and was very pleased with what I heard. I decided afterward to do the 92 degree tilt as championed by Mikey Fremer and others. Well, I pulled out my digital SLR with marco lens, set up the cart so that I had a small 90 degree white card behind it (measured with a small T-square) and went through pics and adjustments until I got to 92 degrees. I measured the SRA by importing the images into Photoshop, using the orthogonal edge of the white card behind the cart to square up the image, and then using the Ruler tool to draw a line bisecting the stylus tip and then looking at the offset angle. Looks very much like the pics I've seen online. I verified that at the start, I was actually just about dead on 90 degrees, so at least it told me my cart was pretty well put together from the get go before I went down this path.

Well, after realigning the cart, rechecking tracking force and so on and making sure things were spot on I sat down to listen. I was not pleased. What I heard was harsh, edgy, and biased toward the higher frequencies. I lost much of the natural balance I had with the stylus at 90. It started me wondering if a cart with a plain old conical stylus like the Denon was really meant to be set up with a 92 degree tilt. I understand why it's supposed to be that way, but it sure didn't sound better in my system. Has anyone else found their TT does not sound as good when the SRA is set to 92 degrees?

[orthobiz]

I never measured my styli but would be interested in seeing any pics you can post!

Paul

[tonyptony]

Paul, I can post one in a bit but in the meantime here's a good one from the web.

[neobop]

Seems like a lot of trouble to mess up the sound.
Trust your ears.

neo

[tonyptony]

Seems like a lot of trouble to mess up the sound.
Trust your ears.

neo

I should have left well enough alone, but this is supposed to be the "right thing to do". 

[tomytoons]

In theory and according to most instructions when the arm is level and the correct VTF is applied the stylus should be near 92/93. Some manufacturers give you the figure.
I never messed any further except for tweaking by ear to the sound.
I'm not about to microscope it. But that's me I never worry about it.

[neobop]

I don't know what the deal is.  I never bothered with something I can hear for myself. 

I did read one of Fremer's articles and I know it's hard to get an accurate photo.  Mikey and followers send their photos to a lab for professional analysis.
The original recommendation was for 91o and Mikey changed it to 92.  If the angle is increased and it doesn't sound "right", you'll get nasty 3rd order harmonic distortion - on the bright side.  If the angle is going a little the other way results tend to be slightly subtractive and benign.

Maybe you can try to lower arm half way to the original position and see what that does.  Try some different records.  If it's still not right, IMO you should lower the arm to where you had it in the first place.  LOL sometimes I think we all need professional analysis.
neo

[tonyptony]

If the angle is increased and it doesn't sound "right", you'll get nasty 3rd order harmonic distortion - on the bright side.

And there we go. Curiosity, cats, and I should have left well enough alone. Now tomorrow I'll have to pull the table off the shelf and try to get things back to where they were. 

[SteveFord]

Does anyone know if this is dependent on stylus shape? 
I try to shoot for 92 degrees which works well for the Shibata found on the 2M Black.

[neobop]

Does anyone know if this is dependent on stylus shape? 
I try to shoot for 92 degrees which works well for the Shibata found on the 2M Black.

Supposedly not, but I don't see how a shibata could be the same.  The facet on the back side of the tip is at a different angle than the front facet.  Maybe you just draw an imaginary line from the center of the diamond at the base, to the end of the tip?  You can find the info on Fremer's web site.  This whole thing was recreated by Wally Malewitz and Fremer popularized it.  The original basis for this is from '81 and was published in High Fidelity and Audio magazines.

Optimal SRA actually varies over a range spanning around 6 degrees, but 91 degrees should be good for about 80% of all records.  Check out this Asylum post by John Risch, one of the originators.  The other guy is named Maier.
http://db.audioasylum.com/mhtml/m.html?forum=vinyl&n=1240&highlight=sra&r=&search_url=%2Fcgi%2Fsearch.mpl%3Fsearchtext%3D%26b%3DAND%26topic%3Dsra%26topics_only%3DY%26author%3D%26date1%3D%26date2%3D%26slowmessage%3D%26sort%3Dscore%26sortOrder%3DDESC%26forum%3Dvinyl

neo

 

[tonyptony]

I just finished messing around with this again. I picked a couple of tracks that I know very well and started with the cart level. I moved it around a bit and wound up with what I think is very good sound, although I have to admit this kind of thing makes me dizzy real fast. Adjusting the arm height and recalibrating stylus position, VTF, and contantly rechecking things was a chore. Near as I can measure I'm now at 90.7 dregrees. I don't want to do this again unless I have to.

Now I know why people might invest in arms with on the fly adjustable VTA.

[Wayner]

If you have to go from 90° to 92°, that requires 8mm of height adjustment, that lots of tables don't have. I tried the 92° thing for awhile, after reading Mikey's little article. It sounded "different" but after awhile, I decided it didn't sound better. I did shoot the stylus with my camera, which is capable of a decent zoom. In the end, I went back to the parallel arm thing and have been happy with that. Since I have 6 AT440MLa carts, they are all set the same way.

I guess it's probably good to go for the adventure, but me thinks that sometimes, Mikey is just plain full of it. I agree with Neo that it's probably related to stylus cut, etc.

Leave bread crumbs behind if you decide to go down the 92° SRA path.

Wayner

[tonyptony]

I just finished playing another album and I think I'll leave it where it is.

I miss TCG.

[woodsyi]

I wouldn't go that far.  Mikey does this for living.  I doubt he is just making it up.  I am sure carts he used showed a difference but it doesn't have to mean it works for every cart.  It's a daunting task to change SRA when you don't have a VTA adjustment on your arm.  More power to you, Tony, for trying.  I have adjustments on my arms and I basically have gotten to the point of setting it where where it makes music the way I like it.  I pretty much comes to the parallel position that Wayner talks about. 

Happy listening.

[tonyptony]

I do like my Akito 2B, but this sort of thing makes me wonder about something like an Audiomods arm with the VTA micrometer.

[SteveFord]

Albums used to be fairly consistent in weight (thickness) but now I've got everything from super floppy to 200gm monsters.
Adjustable arms are a good thing if you have a large record collection.

[neobop]

I do like my Akito 2B, but this sort of thing makes me wonder about something like an Audiomods arm with the VTA micrometer.

If you were happy before you started messing with SRA, maybe you could put it back where it was and be satisfied?  This is a complex problem and one aspect is vertical contact area of the stylus.  The greater the vertical contact, the greater the problem.  Even though the elliptical has the smallest contact patch, a little oval, the spherical tends to be more immune because the contact area is round.  But despite common misconception, it is not free of SRA considerations as evidenced by your experience.  As vertical contact increases from elliptical to hyper-elliptical, through shibata, line contact and micro, the problem increases.  The angle of the cutter head on the master, has to be duplicated exactly by the playback stylus to get a "perfect" reproduction, and that ain't easy when the angle varies record to record. 

LP record thickness has always varied dramatically, but that's only part of the problem.  There never was any SRA standard adhered to by mastering engineers.  Cutter head angle is calibrated in VTA, not SRA, but that is adjusted according to the engineer's reckoning.  The VTA "standard" was also changed, gradually from 15 degrees to approx. 20 to 22 degrees in the '70s and '80s.  The FACT of the matter is, SRA varies over a range of approx. 6 degrees (not including record thickness).  All is not lost though.  80% of all records can be played back with little or no SRA problem, if you nail this average arm height setting - the set and forget school.

I suspect the reason it was so bad at 2 degrees forward of vertical, was due to photo error.  You can't just put a 3 x 5 card on a record surface, snap a photo, and expect perfect results.  Records aren't flat to start out with, and unless you're really careful with a tripod and angular measurements, you'll get parallax error.  A perpendicular line should be oriented from the platter not the record.

As I posted before, Fremer only revived this stuff from '81, he didn't invent or discover it.  If someone can't hear it, or doesn't know what they're doing, maybe this could be helpful.  Seems like an awful lot of trouble for something so obvious.  I guess if you really can't hear, like Roy Gandy, it wouldn't matter anyway.   

BTW, Mikey is a member here.  He posted on this very subject, so watch what you say.   
neo

[Wayner]

Why is he any different then anyone else?

Wayner

[dlaloum]

Suggested reading.... http://www.vinylengine.com/turntable_forum/viewtopic.php?f=46&t=53152

Interestingly the complex behaviour of the shibata tip is discussed - the contact patch of the shibata is not strictly linear, it has a slight curve....

I have never seen a decent comprehensible summary of shibata behaviour with SRA/VTA...

I am uncertain whether that curve is an advantage or an achilles heel, it may be the main reason why designers went down the path of more sophisticated and more linear profiles...

[woodsyi]

Why is he any different then anyone else?

Wayner

Wayner,

Everyone is different and yet we strive to treat everyone equaly including you.  I don't think you are full of it even when you get a little ornery.  I would like to see everyone treated with respect here.

Thanks