[neobop]

David,
I didn't read the paper, but the conclusions would be consistent with the Ortofon paper - response/phase measurements. It's undoubtedly the high frequency resonance that determines the primary phase nonlinearity. 4-ch carts had to have usable response past 30K. Companies like AT also seemed to keep the inductance very low.

Many of the MM/MI classics were developed after quad died out. Higher output was considered desirable. Of course inductance went up along with output. The shibata tip was developed for quad. And I think the fine line or line contact was developed just after. All the micros came much later. I believe VDH invented the microridge in the '70s. AFAIK all quad carts had shibata or .2 x .7 elliptical tips.

I suspect that too much credence is given to the implications of moderately higher inductance. If response is extended, then another 50 or 100mH isn't going to make all that much difference IMO. Carts like the 881, V-15, 20SS, 170ML, F9 Ruby, etc all had inductance in the 400 to 500mH range, I believe. Maybe a couple of the classics had somewhat higher inductance. It's the ones with inductance in the 600 to 900mH range, and even higher, where you can really hear it, especially if response isn't all that extended.
neo

[bauzace50]

Hi neobop, and all,

I've been lurking here since joining yesterday!  Great to cross paths with great mates from other navigations!

I have not yet read the thread, so this question may have been answered.  In what manner is phase shift audible at home?  Is this the issue?  I have not experimented extensively with this BUT actually ran into an intriguing situation.

     My new and ultra inexpensive Ortofon Omega cartridge shows "out of phase" behavior which is different from ALL other cartridges I've tried on the Shure TTR-117 (ERA V) test record.

     It is the "phasing" band on the record, where the announcer states "My voice is recorded in / out of phase, and should be heard...thusly". 

     I ALWAYS listen to this band over headphones.  It is unequivocal...never fails!  The "in phase" phrase is always heard coming from the top of the head, very well focused and centered.  But the "out of phase phrase always comes from halfway to the rear of the head...you might say at 45 degrees towards the rear of the head.

     But this ortofon!  Confounded fellow!  The "out of phase" message comes from fully to the rear of the head, or 90 degree difference as heard over HEADPHONESS  No other cartridge has behaved this way in about 30 years of listening to the band.

Implications?  I have not yet experimented...sorry .  But if this is of any use, please say so, and I will experiment.  Even more, I am willing to send the cartridge to neobop's studio for actual audition of this phenomenon.

Great to be back in this company, and let me know,

bauzace50

[neobop]

B50,
Welcome to the monkey house my friend. Seems like old home week around here. Maybe new home week!! 

This thread is an exploration of nonlinear phase behavior. Specifically, LO carts vs HO. No actual testing was done. I have no equipment to test phase behavior on this level. Most of the conclusions are based on an old Ortofon paper that showed phase vs amplitude plots for 5 MM carts and the MC200 with varying amounts of damping. This was done with an accelerometer and precise measurements of the actual output.

Over at the Asylum it was suggested that Hagerman's electrical resonance calculator could be used to plot phase deviation in carts. Hagerman never said that, AFAIK, and it turns out they were wrong. It was also suggested that phase deviation is one of the primary reasons that LOMCs tend to sound clearer, more transparent etc. It could be a factor, but is nowhere near as different as they suggest.

What's an Ortofon Omega? I went to their site and saw no Omega. Knowing you, it's probably an A-90? Anyway, I've never used that test record, but it seems like 90 degrees actually yields 90 with the Omega. My guess is that it has far superior separation/crosstalk. Blending the channels would reduce the effect. I would imagine the imaging with this cart is uncanny. It would tend to image the way the recording is cut, w/o the blending? What are the separation specs, vs frequency?

Last year I actually got a test record. It's the Analogue Productions one. Peter (Soundsmith) suggested I should get it for azimuth. But I don't seem to have a problem doing it by ear. I haven't gotten around to opening the record. LOL it's still sitting there.
Glad you're here buddy,
neo

[bauzace50]

Hi neobop,

thanks for your comments!  The Ortofon Omega is a very INexpensive, rock bottom cartridge for guys with USB turntables!  I wanted to see what Ortofon could do with $30. price, and did a 2-member bicycle with it...nobody else seemed to be interested! .  The A-90 is in my Impossible Dream list!

The bicycle consensus is that Ortofon can summon their corporate muscle to produce something good at $30.  There is NO audible treble peak (great news for me), but there is some treble grain.

Insofar as its unique phase behavior, I am willing to let it travel for members' experimentation.  But my experience with it is entirely anecdotal.  No rocket science here,  and I'm not sure if this is in tune with your purposes.

If you'd like to put it to some tracks yourself, let me know.  It may fit your purpose...  can be seen at www.needledoctor.com/Ortofon-Omega-Phono-Cartridge?sc=7&category=971

Regards,
B50

[neobop]

Ah ha!  One of your ridiculously inexpensive carts. Wishful thinking I guess,  about the A-90. I have no idea what's going on with the phase thing. Here I thought I had it figured out. The separation isn't particularly good, so maybe it errs in the other direction, toward mono? 

Looks like a lot of cart for $30. Will it take an OM stylus? If so, you could put a Gyger or whatever the OM40 is, on there and have a $300 stylus upgrade. Sounds like something I'd consider. LOL Like my AT-95 adventures. Seriously though, maybe the grain is coming from the bonded tip. The specs are incomplete at NeedleDr. I assume it's a bonded elliptical of some sort. Upgrade the tip and I suspect it will resolve more, but the highs might get a little more aggressive. The OM20 stylus, a nude elliptical might clear that up.
neo

[BaMorin]

Ah ha!  One of your ridiculously inexpensive carts. Wishful thinking I guess,  about the A-90. I have no idea what's going on with the phase thing. Here I thought I had it figured out. The separation isn't particularly good, so maybe it errs in the other direction, toward mono? 

Looks like a lot of cart for $30. Will it take an OM stylus? If so, you could put a Gyger or whatever the OM40 is, on there and have a $300 stylus upgrade. Sounds like something I'd consider. LOL Like my AT-95 adventures. Seriously though, maybe the grain is coming from the bonded tip. The specs are incomplete at NeedleDr. I assume it's a bonded elliptical of some sort. Upgrade the tip and I suspect it will resolve more, but the highs might get a little more aggressive. The OM20 stylus, a nude elliptical might clear that up.
neo

I'm really not sure that the tip being boded is an issue, either alone or part of treble grain. I believe it to come down more to the profile of probably .4X.7, or .3X.7, and the polish there of. The diamond and its bushing really are a low percentage of total ETM. Most of the "tip mass" is the cantilever, followed by the generator. (Magnet, Iron, Coil) The diamond material certainly isn't going into a resonance. The bushing will not itself resinate at the frequencies induced by the grooves. If it did, the bushing and diamond would most likely seperate.

The grain, if the stylus profile is at least hyperbolic, is most likely due to the various bending modes the catilever is exhibiting and undamped nodal points along the tube.  One has to look at the price point the cart was built to, and to be able to market at a reasonable profit. $30.00 in today's money, and it actually plays music is quite a feat.

I picked up an ADC QLMlll for the same money for evaluation "elsewhere"   What a horrid little wretch that thing is. Dynamic range out the wazoo......no music though. It would probably fit the "senergy" bill for a teenager cranking up AC/DC on his Bose surrounds.

[bauzace50]

Neobop and BaMorin,

so, how are phase anomalies audible?  The Ortofon paper says that linear phase cartridges somehow sound "clearer?"  That's quite a large target area.  Could we put a little bullseye on that target, and tighten the definition?

MAYBE, just maybe, one could start by investigating the "image shift" and image focus ( that is, an image describing a large listening area, OR,  an image describing a tight focused point?)  A large aircraft carrier versus a small racing boat.  They both describe hugely different circles while turning.

With the Omega, over headphones ON THE PHASING BAND, I get a tight, small, focused image on top of my head in normal phase.  That same small focused image jumps to the rear in antiphase.

Other cartridges describe the rearward image in a larger, more diffuse image...more like a rear ambience than a rear image.

If this seems like one point to begin describing audible differences in phase behavior, seems interesting.  Maybe OTHER examples would be more enlightening, and take us to define (tipify) audible examples of various phase behaviors?

don't heed me too much...   You are investigating the measurable phenomenon of phase changes.   I am talking about the audible manifestation of those changes.

Regards,
b50

[neobop]

B50,
You have the audacity to equate measured phenomena with audible consequences? You imply that there could be practical implications?    I must say, I miss the days when I could look at a magazine and see an actual bench test report on a phono cart. The Ortofon article talked about imaging almost exclusively. Asylum conjecture was about transparency and all around clarity, I guess. Even though phase non linearity wasn't usually measured as such, we can probably take a pretty good guess based on performance or specs.

For the record, phase non linearity is about how phase performance differs from overall frequency response, whatever that happens to be. If the balance of a particular cart isn't to your liking, it may or may not have much to do with phase anomalies. But you're right, imaging would be the obvious consequence, as the Ortofon paper described. The higher the mechanical resonance of a cart, the less likely there is to be phase anomalies in the audible band (20 - 20K). So, a MM or a MC with response to 50K, would tend to have better phase linearity. It's physical damping of the cantilever that introduces phase problems. The higher the mech HF res, the less likely it will be to have non linearity in the audible band. The article implied that greater damping was employed in the MMs, and that inductance contributed.

I've read speculation that absence of inductance is the main advantage of a LOMC. But the implication here, is that a moving coil may have a electromechanical advantage as well. When damping was applied to the MC200 for +1.8dB response @ 20K, phase performance was better than any of the MMs and imaging was superior. HF resonance of the MC was 28K.

The unanswered questions are about MM HF res and how much inductance contributed.
neo

[bauzace50]

neo,
ha ha ha haaaaa funny how one expects measured observations to be heard   Non-engineering types, such as me, learn from the discussion!  Thanks.
b50
---NOTE:   manufacturer Hans Ole Vitus, president of Vitus Audio (Denmark?) worked extensively in hearing aid Research and Development, and later went into audio manufacturing.  He is quoted as saying that the ear can detect the smalles phase errors, and we are more sensitive to those than to amplitude differences (The Absolute Sound, April 2011, page 136 "Back Page").

[neobop]

Now that is interesting. I guess it would depend on the type of error, cause they are usually considered to be the least detectable.
If phase relates to location, then I think it would like a built-in instinct, a necessary survival tool for locating prey or predator.

Another interesting thing about our hearing physiology - we have small hairs or receptors in our ears that correspond to 100KHz. Even though we don't consciously hear past 19K, or whatever, maybe we sense much higher frequencies subconsciously.
neo

[BaMorin]

Now that is interesting. I guess it would depend on the type of error, cause they are usually considered to be the least detectable.
If phase relates to location, then I think it would like a built-in instinct, a necessary survival tool for locating prey or predator.

Another interesting thing about our hearing physiology - we have small hairs or receptors in our ears that correspond to 100KHz. Even though we don't consciously hear past 19K, or whatever, maybe we sense much higher frequencies subconsciously.
neo

Even though we don't hear those sounds in a cognitive manner, the waves still shake the ear drum and all attaching parts......those "unheard" tones have to affect the tone we do hear.

[neobop]

Even though we don't hear those sounds in a cognitive manner, the waves still shake the ear drum and all attaching parts......those "unheard" tones have to affect the tone we do hear.

If we take that a step further, phase information in the unheard region would also have an impact on our subconscious perception. If we look to the animal kingdom, whales use subsonics (to us) to locate and communicate hundreds of miles. Dogs can discern the direction of a dog whistle.

I notice my cat seems to like mellow stuff like Bill Evans or even up tempo acoustic records. If I put on a CD she's much more likely to leave the room, even if it's laid back. I can always get rid of her for awhile if I put on a Crystal Method or ZZ Top CD. Maybe it's just taste. She is very picky, a good mouser though. Last year the score was Babycat - 3, mice - 0.
neo

[bauzace50]

Neo,

this is another anecdote, not far from the spirit of the thread, but off the technical side.  I used to listen exclusively through the Dynaquad 4-speaker setup for many years.  The effects were very interesting and usually enhanced the perception of most recordings I heard.  Of course, Dynaquad uses phase differences in order to work at all.

But a few years ago I had to move to tighter quarters ( after I got fazed on occasion of divorce proceedings)  and there was no room for the rear speakers.

Now I listen through a "near field" arrangement, and I swear by it!  Most impressive, movies with rear channel information are heard frequently as if coming from INEXISTENT rear speakers ( no more Dynaquad here), and my system is strictly stereo (2 front speakers)  There is some sort of unintended phase manipulation going on through this "near field" setup, and the configuration of the room...and I don't need fancy black box 4-channel "synthetizers".  It's great when I hear pods  flying in from the rear, and contnuing to the front in Star Wars.

Phase is a very curious thing.

bauzace50

[neobop]

B50,
Thanks for sending me that interview with Vitus. That's really interesting. He used to work for Texas Instruments and checked out the research on digital hearing aid development. He said that we're more sensitive to phase differences than amplitude differences. He also said the ear can detect changes we can't even measure. I don't doubt it.

I remember reading a paper by a doctor doing research with deaf people. It was really fascinating. He could measure physiological responses to sound pressure waves. One way these people "heard" was from the impact on the cornea of their eyes. Just remember, next time you close your eyes to concentrate on the sound, you're actually missing something. LOL

They've been able to simulate surround sound from stereo speakers for awhile now. It's interesting that you hear this phase manipulation with near-field set-up w/o the simulation. Amazon sells a Pioneer 610 DVD player (European model) that has a 24/192 DAC built in. It has a USB connection, upconverts for HD, can simulate surround for 2 speakers, and has a feature that brings up the dialogue while reducing the background sounds. Apparently you can adjust it for a particular movie or scene. This is the future I guess. Music will come from servers or be stored on a drive or something. CDs are already obsolete.

Maybe none of it matters. I just saw a show on the history ch about 2012. The Mayan calendar ends at the end of the last 52 yr cycle in their long count. On 12/21/12 apparently the planets line up again. It wasn't that long ago that they did that, but this time our sun will be at the center of the galaxy. No big deal as far as I'm concerned, but how the hell did the Mayans know this stuff? They also said that the Mayan calender is slightly more accurate than ours. If knowledge is the accumulation of learning, we must be missing some. I think I have it figured out though. The Mayans got their knowledge from the ancient astronauts. You know, the guys who built the great pyramid. I wonder what their music systems were like. Probably telepathic.
neo

[bauzace50]

neo,

Agreed!   Some phase episodes seem crazy.  Like trying to find a cricket from the sound it emits.  One can actually be seeing the cricket but its sound makes it appear to be somewhere else!  Crickets KNOW about phase manipulation.

One example of phase causing apparent contradictions:  the cowboy movies showing a stagecoach running one way, and the wheels appearing to be turning in reverse...similar to stroboscopic weird effects when starting up a turntable with a strobe disc on the platter.

Phase CAN make sound or sight appear crazy sometimes.     One need only know what's causing the effect in order to corroborate one's sanity.
Regards,
b50

[neobop]

Here's an interesting article on human/animal sound localization;

http://en.wikipedia.org/wiki/Sound_localization

[neobop]

I think most people would agree that having linear phase response is a desirable thing. In addition to the implications for imaging, it would probably impart a general feeling of coherence or rightness about the sound. I wonder if some phase nonlinearity can sound good or better sometimes, than not having it?  Considering that most of us like the sound to be a certain way (lush or dynamic etc), we sort of pick our colorations. Not much is 100% accurate, and if it were, would we like it?

Maybe if a treble background sound was brought forward, it might sound good. On the other hand the anomaly wouldn't be selective about what is affected and might sound bad or weird? I guess it could be like having a horn jump out at you more than what's recorded.

This is kind of theoretical and I'm at the point where I don't really know what I'm talking about. If anyone has something to say about this, please do.
neo

[dlaloum]

I think most people would agree that having linear phase response is a desirable thing. In addition to the implications for imaging, it would probably impart a general feeling of coherence or rightness about the sound. I wonder if some phase nonlinearity can sound good or better sometimes, than not having it?  Considering that most of us like the sound to be a certain way (lush or dynamic etc), we sort of pick our colorations. Not much is 100% accurate, and if it were, would we like it?

Maybe if a treble background sound was brought forward, it might sound good. On the other hand the anomaly wouldn't be selective about what is affected and might sound bad or weird? I guess it could be like having a horn jump out at you more than what's recorded.

This is kind of theoretical and I'm at the point where I don't really know what I'm talking about. If anyone has something to say about this, please do.
neo

Have a read of http://www.regonaudio.com/default.html

Especially the first few articles in the "recordings and reality" section.

One of the points he makes is that mainstream audiophilia is fundamentally flawed, and that the standard setup (not to mention the search for air / space / imaging) are in many cases leading us down a path of an artificial (sonic) virtual reality.

He also points out what it takes and how it is possible to record and reproduce, with substantial accuracy, a live audio event. Not talking about studio recordings, and multimiked / multitracked artificial audio constructs...
But with the right setup it is possible to put oneself at a particular seat in an auditorium for a live performance...

He also points out that both recording technology and methods as well as reproduction technology and methods (primarily speakers) have developed together to create a particular virtual reality, which is in its way effective and pleasing - but it does not and cannot, in that form, reproduce a live performance.

Through the various articles he covers phase, reverberation, speaker setup and positioning, as well as recording/miking methods and their results.

Along with issues such as the acoustic differences between romantic era, pre-romantic and post romantic auditoria (reverberation time, and varying absorbance of frequencies...) - and how particular compositions (even particular instruments) were designed for particular environments..... and how when these are then recorded (emotive language warning) - the "wrong" way, the result is far from the intent of the original composers, and even further (wronger!) from the way they sound in real auditoria.

Very good, thought provoking, articles....

bye for now

David

[bauzace50]

David,

 Regonaudio always writes good important stuff and is very well respected.  Thanks for the link, to be read later on with great expectations!

Thanks,
bauzace50

[Roger A. Modjeski]

I may be sorry I'm entering into this thread but I have a few things to say.

Phase shift is boldly in the topic, and there has been a request for an EE to respond. Let it be known that the RIAA EQ in every preamp I know of is a simple RC network which simply reverses the EQ that was supplied in making the recording. Therefore, there are not phase problems. The phase shift in the recording is undone by the phase shift in the playback resulting in no phase shift at the end of the process.

However, If the cartridge has an untamed resonance  in the audio band all bets are off, but this has nothing to do with the phono preamp and the imagined phase shift in it.

Any discussions in the Audio Asylum are best ignored.

PS. 99% of what we call MM cartridges are actually VR (variable reluctance).  GE told the truth with their VR series, where did we get off the track. Pardon me, but i just like to call a spade a spade.