[neobop]

David,
I must say, I think it's imprudent to speculate about phase shift with secondary resonances unless you can show evidence. For example the Grado. I would guess that there is virtually no phase shift at 12.5K other than that caused by whatever resonance you're measuring. Depending on the magnitude of the resonance, that would be localized to the area immediate to said resonance. This could be caused by arm/cart interface or cart body etc or even your set-up. Primary high frequency resonance would cause anomaly that would be similar (hopefully) throughout model. The only measure results so far indicate that suspension damping causes all phase nonlinearities and they are hinged on the high frequency res peak. I realize you didn't just now correlate with phase, but you did in the past.

I think you need a LOMC with extended HF response to test your set-up. Subtract inductance from results and see what you come up with. I don't know exactly how the signal is terminated. It wasn't long ago you had capability only to 20K. Please don't think of this solely as criticism. I'll be glad to help in any way possible. I also have an Analogue Productions test record. This is also said to be flawed with respect to frequency response, but it has some unique tests that you might find useful. These include RIAA checks and distortion test, and cutterhead set-up. The offer stands if you think either of these might be useful.
Regards,
neo

[dlaloum]

Hi Neo,

you are quite right I was implicitly correlating phase with resonances.

The Grado 12.5k Resonance is well documented (take a look at the Miller Audio Research graphs for the Grado Red - and the Grado Gold1 looks identical...).

However due to the ... strange?... electro magnetic structure of the Grado's I have no way of modelling the electro magnetic behaviours and therefore cannot identify whether that resonance is mechanical or electrical.

But I have sought out other tests and reviews of the Grado's and this appears to be common to the entire Prestige series. (the exchangeable stylus Grado's).
Lou Dorren has chose the Grado Gold1 to be the basis of his new CD4 cartridge. This implies it has good phase response above 15kHz. - The fact that this cartridges resonance happens as low as 12.5k may in fact be an advantage in this case due to the rest of the range thereafter not suffering from resonances and therefore being very phase linear - as required for CD4. The frequencies below 15kHz are played back as standard stereo - and less sensitive to phase. (well as sensitive as our ears are anyway... which is not very)

Other than the knowledge that any resonance involves phase anomalies - the Ortofon graphs show a range of different phase variation patterns, related to differing damping methods and intensities.

The theoretical electro magnetic and mechanical models for resonance all show phase anomalies (non linear phase) related to the resonances.
With the mechanical resonances things are substantially complicated by the damping applied (cantilever suspension + additional damping varying by the various designs) - The Ortofon paper shows 4 different phase variances all from an MC200 cartridge cantilever each with a different damping setup (ranging from undamped to very heavily damped).

To maintain consistency in my experiments - I bit the bullet and purchased a LOMM cartridge - a Pickering XLZ - with inductance around 1mH - but it can take any of the stanton 8xx or 9xx series styli - and the pickering XSV/XSP/XLZ equivalents - So I will have both a HO version of this body type and a LO version differing inductances but able to share/interchange styli... so I can more easily isolate and identify cantilever from electrical variances.

I have developed a fairly viable & consistent model for MM/MI performance - it includes the basic LCR modelling, but also a loss factor/slope that allows for the inherent losses in the coils as frequency rises. (this varies by cartridge, but can be measured relatively easily, and is I believe a measure of the quality of the coil structure, materials and lamination).

I also purchased a MC200 quite recently in the hope of using it as a LOMC test subject - but it is the integrated "concorde" version - and it just so happens that it cannot adjust to the relatively short overhang on my JVC arm/Table!!!
So I am hunting for a stylusless MC200/100 of the p-mount or universal mount variety onto which I could plug my stylus. (It is one of those rare removable stylus MC designs, much like the Sony XL-MC's)

It think I have frequency amplitude response measurement under control now - with enough trusted reference points that I have a high level of confidence.
What I need to find is a way to measure frequency-phase variation...

I also have a range of test tracks that should be useable for various types of distortion measurements.

What is the analogue productions test record cutterhead setup track?
I had a serious look at purchasing that record - but at this point, I think I have valid tracks for pretty much everything it offers....

Thanks for the offers - I will keep them in mind

bye for now

David

[neobop]

David,
Do the wood body Grados also have this resonance at 12.5K? If not, I think you have the answer. The HO woodies look like they have the same generator. Perhaps some non magnetic shield damping would cure it. Part of the Grado magic is having an unshielded body. This is no different really than some people preferring unshielded phono cables, or my AHT phono sounding better in a plastic box. If the woodies still have the resonance, then I would guess it's a physical relationship between coils. They may be having coitus?    Don't snicker, they're a married group.

Peter Soundsmith convinced me that I needed a test record to set azimuth on a retip. I have yet to open the record. It looks really impressive. It was Werner who said that the frequency response or anti-skate track(s) was off.
http://www.analogueproductions.com/index.cfm?do=detail&Title_ID=35532

Let me know if it will be of any use. I know how these expenses mount up.

You're measuring a function of time vs amplitude. If your test set-up doesn't allow for this maybe you could get an accelerometer and do it the old fashioned way. You can probably get one for next to nothing in an old Yamaha subwoofer or similar. I don't know what considerations there are for suitability.
neo

[dlaloum]

I honestly don't know about the woodies - have not investigated...

Especially the low output ones!

First issue is if it is electrical related - changes in output (inductance) will shift it

If it is mechanical related - the differing cantilever design (permanent fixed vs removable) is likely to alter the picture as well.

Not sure if it is worth spending time on it...
I don't have an effective model of the Grado electrical response - so I cannot delete the electrical theoretical from the actual to attempt to identify the mechanical resonance....
And because the design is relatively insensitive to loading changes - it makes it harder to identify electrical related resonances (which on HOMM's you can spot by changing the loading and looking for the peak that changes frequency).

With all these limitations - I just can't really gain any headway with the Grado.... I am still recording it as another comparison point in my non-EQ vs EQ testing - but as an analytic exercise.... this one is a bit slippery - I don't have any traction on it.

There was some discussion about some shielding aspects of the designs being different with the woodies vs the removable stylus models ... possibly one of the reasons why Grado moved the upper end to woodies. - Still a fascinating design... indeed a married design !

Yes Werner also warned me about some of the frequency response issues with the HFN test record as well. - Which is why I started cross testing various records and looking for matches and disparities.
The much more tedious spot frequency tests (where you have to measure each spot frequency individually - and there are either 20 or 40 of them) on the CBS records are regarded as a reference... but pink noise can be done almost instantly by comparison!
I can confirm that the HFN tracks are off - and I am getting towards being able to identify exactly how they are off. (I'll get around to that!)

I started hunting for an accelerometer a while back - with the idea of optimising the shelf and plinth using it... but the thought of fitting an accelerometer to a cantilever - the added mass will affect F/R even if I can succeed in fitting it somehow - and all the accelerometers I know of are way too massive!

I wonder how ortofon did it? (they apparently fitted an accelerometer to the MC200 cantilever... !?!?

I still have to find an appropriate combination of tools (software & test track) that will give me meaningful information - at multiple frequencies between 1k and 20k would be nice!

So many conundrums - so little time...

bye for now

David

[bastlnut]

hallo,

here is again the disparity about measured vs observation.
i trust what i hear more than what someone else measures.
i am still not at all convinced that measuring stuff is productive.
with my ears, i can consistently get a better sounding result than using any spreadsheet or basing choices on spectral analysis.

regards,
bas

[dlaloum]

Well yes - If tuning a single item...

But what if you are trying to work out a system to use in efficiently optimising any one of say 50 different cartridges....

Doing it by ear will take months if not years.

I recall reading about the 1930's Merc. racers, they had multi-jet injectors - which could only be tuned by one of two or three engineers who did it all by "feel".
Those cars engines were as efficient as 21st century computer controlled high tech motors.... but every time you tuned them you needed one of the top guys anywhere to do it for you.... and now we have systems that allow your local bloke to plug in an electronic dodad, press a button, and when the little green light lights up - he says all done and off you go.

I am not claiming that an experienced ear cannot be used to achieve excellent results - but I would argue that the process involved is a) inefficient, b) unusable by the inexperienced, and c) prone to a wide range of psychoacoustic issues.

That last one (c) is quite pernicious - how many times have you messed and messed again, improved and improved and 6months or 2 years down the track, temprorarily put an old component back in the system (perhaps while something is being fixed or on loan) - and lo and behold it sounds better...

Those incremental "by ear" improvements sometimes focus on one aspect at the unconscious detriment of another.... very very hard to achieve consistent repeatable results!

But yes up until about a year back, I did everything by ear - like most of us.

Then I decided to investigate the tools available in our maturing computerised audio world..... and discovered that things that 20 years ago were only possible in a fully equipped (and very expensive!) lab - could now be done at home with free software....
No longer am I dependent on lab tests in a review - which often don't cover an aspect I am interested in, or don't publish all the parameters of the test, making it non replicable!


There is also a problem in the "I trust what I hear" statement - especially given one of my very first tests which led me down this path.

I took a series of differing cartridges (Ortofon 320u, OM30, Shure 1000e-SAS, Benz MC1, Sony XL-MC104) and started comparing.

They sounded different in a whole bunch of ways (all were using a standard Creek OBH18 Phono stage 220pf/47k + cables pf)

So I recorded the same record using each of them and compared them back to back using multitrack software (one cartridge per stereo track, time aligned so I could switch between them).... yep they all sounded different (I still have the listening notes...)

Then I used the Cooledit analysis to look at average RMS, peak values etc - trying to identify what made them different....

Then I normalised all the recordings on peak values - they all sounded just as different.
Then I normalised all the recordings on average RMS values - and suddenly a layer of difference disappeared !!!!

No editing had been done, no filtering or messing with EQ - all I had done was amplify (or decrease levels) so they all had matching average RMS levels.

Were they still different - Yes they were - but the differences were suddenly made much more subtle.... the ear and mind were being tricked by level differences!

So I then read further on psycho acoustics and the perception of sound, and in particular what amount of level difference is audible - even if one is unaware that the change in sound is caused by a change in level.

One of the Regonaudio articles pointed out that a boost of 0.2db in a very narrow frequency band is clearly audible....

So we can discern variations in level of at least 0.2db and most likely less....

And our hearing can discern these variations within specific frequency ranges - But in most cases it is not consciously discernible as what it is. (psycho acoustics again)

Based on all the above, and other articles, and more lately my own experiments - I am convinced that we cannot simply "trust what we hear". At least not in an analytical sense.
A cartridge or component may sound better simply because the level has been adjusted 0.2db higher - how meaningful is that!!
And the only way to avoid this, is using long term listening methods (install, listen for weeks or months, then go back to the original - do the same, etc...) - where these level variations become irrelevant.
Danger is that our short term sonic memory lasts about 3s - hence the advantage of instant A-B testing for certain types of differences.... some things just get missed otherwise.

If by productive you mean conducive to more listening to music - you could be right, it takes up a lot of time - which could be spent listening.

If by productive you mean conducive to an overall improvement in the system involved - I would disagree with you.... my TT is definitely sounding better!

Still wearing my analytical hat, I would suggest that the difference between the two perspectives is a question of Cost-Benefit analysis with a bunch of value judgements involved in both sides of the equation!

In any case the spreadsheet and spectral analysis does not replace the ears... instead it helps by allowing one to identify specific patterns and measurements that the ear finds pleasing.
It also helps in that you can identify configurations that might work well - without having to spend hours/days/weeks experimenting - which is the point of effective modelling.

And it assists in tuning / level matching comparison tracks so you eliminate the psycho acoustic influences - and can then allow the ear / brain to make a much more effective choice.

In other words all the analytics do not replace the ears - they just help me to use the ears most judiciously and to greatest effect and efficiency.

As an example - my listening to the ADC cartridge described earlier - I chose which loadings to use based on modelling - but then listened to 4 differing configurations - and they were clearly different, even when level matched and EQ'd. I know in measurement terms which of those were the most accurate in reproducing the recorded sound.... but I am not yet sure which of them I prefer to listen to! - The 50pf/80k setup was really nice - but due to its slight upward tilted high end (very MC like) - it may end up not being ideal for all types of music - sort of a tendency to a certain "sound" rather than reproducing the sound of the recording.... The very flat F/R EQ'd version sounded almost as good, and will reproduce much more accurately the soundspace recorded, rather than influencing it - possibly euphonically.

More listening and use of ears required!


Bye for now

David

[neobop]

 


P.S. Somehow the accelerometer was said to be on the headshell. I can't conceive of how it could possibly work on the cantilever, or I should say how the cantilever would possibly work. There's a corresponding AES paper. I think these can be purchased. I'll see what I can do.
neo

[dlaloum]

Had a look at the Miller Audio Research measurements for a Grado Master Reference... one of the woodies...

In their measurements there is a resonance at 9kHz, and signs of a possible second resonance at around 15kHz.

Unfortunately I cannot draw definitive conclusions as the generator, although of the same overall design, is a very low output low inductance/resistance version - so its electrical parameters are quite different....

There is also a distortion peak at 15kHz - which makes me suspect a mechanical resonance at 15k

There is another distortion peak at 5.5k... ?!? why ?!?

I feel about the Grado's the way I felt about standard MM's about a year back - mysterious box which produces sound - different ones sound better or worse than others.... no understanding of why, where, or how.

Bye for now

David

[neobop]

David,
Although I know nothing of the test procedures and equipment used for this study, all tests are subject to evaluation or question. As Marc suggests, tests are often done using Grado's recommendation of a med/heavy arm. It's also been implied that bearing design has dramatic implications with these. John TCG says that the cantilever is relatively undamped. You know as well as I, if that is the case the potential for excellence would be great for certain aspects, while making it prone to fault.

I previously stated on this thread that your own detection of resonances should be cross checked and efforts made to confirm. Please don't think of this as being too critical. Your tests and conclusions have considerable weight and influence. I have a feeling that they are much more than you suspect. Keep it up and you'll become the preeminent authority on much of this stuff. In the mean time you could use a couple more arms.

My experience with Grado is limited. Last time I heard maybe the best rendition of Ella Fitzgerald ever. The other problem might have been physical isolation, I'm not sure. I suspect one of those resonances is from the coils, I don't know. Think of Grado as a special case, like putting the cart before the horse.
neo

[*Scotty*]

dlaloum,What happened to the idea of using the precision inductors the respective cartridge bodies cancel out the effects of inductance in the Grado and Audio Technica cartridges.   
Scotty

[dlaloum]

Hi Scotty,

It appears to work well...

The original concept was to provide a similar level of flexibility for users with a fixed loading phono stage, as is available for users with variable loading phono stages.... primarily a way of simulating lowered capacitance. - hence my name for it - the Capacifier. (Pacifies capacitance...)

After a series of tests, I sort of put that to the side, and focused on the basic system...

I have a vague feeling it might be doing something a little similar to what Grado's do internally.

The trouble with this stuff is there are so many variables it is easy to get lost in all the possible permutations and combinations.

Full understanding of the ramifications of the capacifier will require A LOT of testing - it doubles the number of variables in the system.

But fundamentally - it provides much better control of the base electrical response of the cartridge in a fixed load setup. - ie: it works.

The capacifier stuff then led me to look closely at the real vs modelled response, and the modelling used in the capacifier allowed me to identify the cantilever resonances ..... which made me realise the importance of the cantilever resonance (and associated damping) in the "sound" of a cartridge.

It is all part of the search for the Holy Grail of vinyl .... the "perfect" cartridge/setup - and understanding what might result in perfection.

What it led me to was that you need to know / understand the cantilever behaviour first - finding the right stylus/damping is the #1 priority (and manufacturer info tells you almost nothing!!)

Once you have found the right stylus - you then grab a cartridge body that it fits onto -and tailor the electrical response around the mechanical response.(your fixed points being cartridge inductance and cantilever resonance)

This is where the capacifier can come in ... it provides this level of flexibility for the 90%+ of users without loading adjustability.

In setting up the electrical parameters - my personal goal is to eliminate or at the very least minimise phase anomalies as well. (hence this thread) - but due to a lack of measurement tools, phase is a bit of a black magic area where a lot of guesswork is used. (!)

Most MM/MI cartridges us a dash of electrical resonance boost to fill out the midrange - this unfortunately has a definite non-linear phase effect on the response.
Which is not to say that the response will be unpleasing! - The Shure V15-II, III & IV are all examples of this approach! (Not the V)

One of the interesting side effects of the capacifier can be (depending on settings) the replacement of a fairly sharp phase non linearity with two very shallow phase non linearities - alongside a substantial extension in top end frequency response - Limiting phase variation to under 15 degrees at two places in the spectrum may be an improvement over a phase variation peak of 90 degrees at a single frequency.

In any case these are just musings....

Currently the base capacifier spreadsheet is available at http://www.luckydog.demon.co.uk/images/capacifier.xls

I've got some working refinements to it that overlay measured results, and also uses measured results to calibrate the model - which then takes into account mechanical resonance ... becomes much closer to reality than the purely theoretical electrical model in the base spreadsheet.

But it is very complicated to use.

For people interested in custom loading their cartridge, without mods to their phono stage - I strongly recommend the capacifier... non intrusive and it works!

bye for now

David

[neobop]

"The original concept was to provide a similar level of flexibility for users with a fixed loading phono stage, as is available for users with variable loading phono stages.... primarily a way of simulating lowered capacitance. - hence my name for it - the Capacifier. (Pacifies capacitance...)"

This is a box you plug into that uses inductors like Scotty does? This spreadsheet is used to determine values of inductors? It's hooked to the ground of the phono stage? What's the deal?

[dlaloum]

I'm no physicist or Electrical Engineer..

But the circuit is fairly simple...


Level 0 is the normal setup R being the phono stage capacitance

Level 1 is added on to it in parallel with R... you now have an inductor (another cartridge is used as the inductor) and a resistor.
This is the capacifier - the effect is similar (not quite the same) - as having low capacitance cable.


Level 2 was an additional development based on having a low capacitance and high resistance initial setup - for that matter it allows more variability as the model does cover varying all the different parameters.
It allows a level of EQ to be applied to dampen any resonances that are there.

For more details you need to read the very long thread associated - in which I tested numerous cartridges with different parameters on it, a couple of people have built and used it with quite a bit of success...

The basic premise for it became a bit redundant for me after I purchased a fully adjustable phono stage, and modded my TT cables to achieve a total capacitance of 50pf. 

It is relatively simple to build, and it does the job...

There were also discussions around other systems including active ones and applying bias to cartridges.... but none of those were developed - this was built and tested by at least 4 different people that I know of, and two of those are now using it every day...

It is not connected to ground - but to signal ground... I made mine using a p-mount adapter so I could quickly swap "inductors" for different values, and RCA sockets for the R & C values for rapid changes and testing of different values... a sort of lab rig.

bye for now

David

[neobop]

I'm no physicist or Electrical Engineer..

But the circuit is fairly simple...


Level 0 is the normal setup R being the phono stage capacitance

Level 1 is added on to it in parallel with R... you now have an inductor (another cartridge is used as the inductor) and a resistor.
This is the capacifier - the effect is similar (not quite the same) - as having low capacitance cable.


Level 2 was an additional development based on having a low capacitance and high resistance initial setup - for that matter it allows more variability as the model does cover varying all the different parameters.
It allows a level of EQ to be applied to dampen any resonances that are there.

For more details you need to read the very long thread associated - in which I tested numerous cartridges with different parameters on it, a couple of people have built and used it with quite a bit of success...

The basic premise for it became a bit redundant for me after I purchased a fully adjustable phono stage, and modded my TT cables to achieve a total capacitance of 50pf. 

It is relatively simple to build, and it does the job...

There were also discussions around other systems including active ones and applying bias to cartridges.... but none of those were developed - this was built and tested by at least 4 different people that I know of, and two of those are now using it every day...

It is not connected to ground - but to signal ground... I made mine using a p-mount adapter so I could quickly swap "inductors" for different values, and RCA sockets for the R & C values for rapid changes and testing of different values... a sort of lab rig.

bye for now

David

Level 0,  R is resistance or input impedance.
Level 1 has the inductor or cart body in series with the input resistor. This is like Scotty does to cancel the internal inductance. For those who this looks like hieroglyphics, it's different from adding a load resistor. That would look more like the bottom part of Level 2.

If somebody needs additional capacitance, get silver mica ones and load them just like a parallel loading resistor. The burning question is, if you can optimise capacitance on a low inductance HO cart, how much improvement will be realized by cancelling inductance? This is what can be measured in terms of resonance. I suspect all the rest like adding capacitance and/or resistance is mostly for high inductance carts. Notice that resistor R2 is in series with preamp load resistor, not parallel, so it's value would be additive.
neo

[dlaloum]

Level 0,  R is resistance or input impedance.

Oops - indeed...! don't know why I put capacitance there!

If somebody needs additional capacitance, get silver mica ones and load them just like a parallel loading resistor. The burning question is, if you can optimise capacitance on a low inductance HO cart, how much improvement will be realized by cancelling inductance? This is what can be measured in terms of resonance. I suspect all the rest like adding capacitance and/or resistance is mostly for high inductance carts. Notice that resistor R2 is in series with preamp load resistor, not parallel, so it's value would be additive.

I think the level 2 can be useful with some troublesome cartridges where you are having a problem achieving flat(ish) frequency response.
(I always say flat-ish - as I have yet to see a cartridge that achieves something close to flat f/r!!)

But most recently I have been using Ozone4's spectrum matching capability, in combination with pink noise to provide EQ...
This EQ is very high quality (64bit linear phase maths) - and avoids some of the phase issues present with analogue methods...
But also, best results are achieved (I am guessing and theorising.... and testing this theory) by first setting the cartridge and its load up for a configuration which is as flat as possible while avoiding any electrical resonance.

This can be calculated - and the capacitance & resistance loads chosen for a value that is below the "critical" point (the point at which a resonance starts to develop at the frequency response shoulder), while being as flat as possible.

Then using the Digital EQ to provide the next level of adjustment to boost or depress areas that need it to provide a flatter f/r.

Results so far are very very promising. I am still learning how best to combine these variables... but I am finding that I can take a cartridge that sounds very good and has +/-3db response 20-20k and turn it into a far more neutral cartridge that still sounds excellent and has f/r of +/- 1db and possibly +/- 0.75db

All while maintaining linear phase...

The limitations on the Digital EQ are primarily driven by the imperfections in the Pink Noise tracks I have available to me.... so it is not possible to tighten the EQ parameters with this method beyond what I am getting now I think.

Manual digital EQ could probably achieve a marginally better result, but it would take a huge amount of time for each cartridge/stylus/loading configuration.... I have experimented briefly with manual EQ setting - If I wanted to spend the rest of my life doing this, I could do it - but I don't so I have set it aside...

Once I have this ironed out and working properly, I will be able to compare cartridges with known phase anomalies in the audio range with ones that minimise phase anomalies, while having the amplitude F/R sufficiently similar that differences are likely to be related to phase rather than amplitude.

Of particular interest: Shure M Series with SAS vs AT20ss vs ADC SXLM vs OM30

The Shure M with SAS is a very fine setup indeed - but one with known phase anomalies at 15kHz due to mechanical resonance, and in the standard factory recomended configuration, an additional electrical phase peak at around 10k.

The result is non linear phase from around 5k to 6k.

The 3 other examples all have the mechanical resonance above 20k (so related phase anomalies are limited to above 15k) - and can be configured for a completely linear phase in electrical terms.

Also none of these are what one would call a 2nd rate cartridge!!

bye for now

David

[neobop]

David,
I'm far from being an EE myself. I know a little something about resistors, caps and inductors from designing X-overs for speakers. Level 1 is exactly the same as a zobel (impedance compensation) network for a driver, except instead of an inductor it's a capacitor. A cap in series with a resistor, put across the drivers terminals, will limit the rise in impedance (as freq increases) of the driver. That resistor will be in parallel with driver impedance above any freq defined by the value of the cap. Sometimes it helps to look at things in a different way. A cart and a speaker are both transducers, only at opposite ends of the chain.

I put out a call on Agon thread for that AES Ortofon paper. It's paper #1866, convention 71. I'm afraid it might have been overshadowed a rant about tubes and ICs. I wanted to discuss carts. Anyway, we'll get it eventually and maybe it will have a description of methodology. I think the accelerometer monitored cantilever movement and compared it to the output? There are other ways to observe phase vs Fr resp. A square wave will indicate phase nonlinearities by seeing the angle of the top horizontal line of the output. The rise time of the cart will be indicated by the left hand vertical line and how far off it goes from being a straight line. Implications of square waves go way beyond the frequency being tested. Times 10, I believe. Another interesting note, no dynamic loudspeaker comes close to being able to reproduce anything that resembles a square wave. An electrostatic speaker is the only type that I know of that actually can reproduce one. A waterfall plot will show decay. You have to be careful of not measuring the preamp, I would think.

Everyone seems to have their own preconceptions and says selectively that certain things don't matter. But do these tests right and confirmed results don't lie or have another agenda.
neo

[dlaloum]

I saw that - was wondering what the exact paper was...

I may make some mention of it on that thread to remind people!

I was reading the B&K paper mentioned on that same thread and they talked about exciter/accelerometer based measurement of cartridges and how to do it in the paper - I sort of skipped over it as I could not see a practical use of it for me... (given that I do not have access to those specific type of tools.)

I do have a couple of square wave test tracks now... so I can take a look and see how it comes up.

The trouble is what I am looking for is a nice neat plot of Frequency vs Phase (in degrees) - so a perfect flat line is the target, and peaks/troughs become easily visible.

Although a subjective analysis of a square wave can tell us a bunch of stuff - it doesn't give us a proper frequency/phase plot.

Still looking for a combination of software and test track that will enable me to plot phase F/R...


As a long term user of electrostatics - I do not need to be convinced of their benefits.

2 pairs of Quads left my home about 5 years ago - mostly due to their size...
(I still have a pair of 57's and their matching 303 amp in storage... the 63's and 989's went)

They only left after I had auditioned a pair of (remakably compact!) Gallo Ref 3.1's and found them to be "adequate" if not perfect... (my Quad 989's were a distinct step closer to perfect...)
Their CDT tweeter is not bad... (and from someone who has listened to nothing but ESL's for 25 years that is a bit of an understatement)

Still when it comes to microdetail - things like being able to differentiate seperate instruments within the mass of a symphony orchestra at full crescendo ... the Gallo's don't quite make it... the sound is that little bit more confused.... could it be a phase issue?

It also raises the question of whether most listeners have a setup (and most especially speakers!) on which phase is sufficiently linear to be able to discern phase issues....

in 99% of cases I suspect the answer is no - as soon as there is a traditional crossover network - your phase is more or less stuffed, and that includes most speakers.

Which explains why most people claim phase variances to be inaudible.

Bye for now

David


P.S. the Quad 57's are probably not phase linear either due to tweeter/woofer setup, the 63's on the other hand were measured a number of times, and are lauded for being able to pass a Square wave...
The 57's have a sweeter midrange - but the 63's/989's and later models do everything else better...

[neobop]

I suspect you're right about being able to discern phase anomalies. except for 1 thing. Ortofon claimed that listening tests showed that they clearly affected imaging. Assuming this is the case, I would guess that a square wave at 1 or 2K would clearly show differences.

The problem with putting too much credence in summaries is that you have to compare to actual results. It was only the undamped MC that was spectacularly superior, but was unlistenable due to ear-bleed Fr resp. When damped for only a slight rise, anomalies went down to 8K. The worst MM under test had problems down to 2K. Phase is certainly an interesting aspect but what is an exemplary MM compared to the MC200?
neo

[dlaloum]

I'm not doubting that it would show it...

but it would not measure it.

I have a number of good MM's with resonance at 21k to 23k - the amplitude effects go all the way down to 15k or below...

Question is how far down do the resonances phase effects go... square wave tests tell us a little bit - but not enough...

Bye for now

David

[neobop]

I'm not doubting that it would show it...

but it would not measure it.

I have a number of good MM's with resonance at 21k to 23k - the amplitude effects go all the way down to 15k or below...

Question is how far down do the resonances phase effects go... square wave tests tell us a little bit - but not enough...

Bye for now

David

A couple of yrs ago it seemed like there was nothing more to say. But I now think, even if you used an accelerometer to measure, it might be difficult to differentiate phase nonlinearities caused by damping from those caused by secondary resonance.  The Ortofon plots on the tests previously referred to, didn't seem to show any noticeable anomalies outside of the gradual phase discrepancy caused by damping.  I'll have to look at the plots again. It could be that secondary resonance caused phase anomalies were too minor to see, or they don't exist. I don't know if further investigation was persued using square waves. I was under the impression that sq waves would show transient response and amplitude rise or fall, but not phase.  Any input on this subject is welcome.
neo