[dlaloum]

The digital EQ part of the project is a different exercise...

I am trying to work out how much of the difference is only frequency response related, and how much is other aspects (time, phase, dynamics, trackability, etc...)

Especially given that many of these cartridges have cantilevers that should theoretically be at a similar level of quality.

I think I have mentioned this before - the thing that started this project, was my first comparison of 4 cartridges - when I matched their levels precisely based on average/rms levels - I found that they all started to sound very much alike - many of the differences I was initially perceiving were due to the psycho-acoustic reaction to volume differences.

But on thinking about this further, I realised that frequency response feeds into level differences - and you cannot in fact match levels unless you have also matched F/R.

If these two are matched - I therefore theorised that almost all the differences would evaporate.....
 And if NOT - then the differences left will be known to be NOT F/R related - so I can then focus on other aspects.

Taking the digital EQ approach also allows some other things - an electrically phase linear response can be set up, with amplitude response being corrected by digital EQ - so you can go for very low capacitance setups, and compensate for the midrange drop. This may not be as good as it seems, as the amplitude drop, probably indicates something that most likely is also impacting on phase.... I'm still thinking about this - and searching for more information on mixed phase cantilever behaviour. I came across some stuff referring to cantilevers in electron microscopy - it looks similar enough to stylus cantilevers that some of it might be of relevance.

My spreadsheet model (which I really should cleanup and publish on the website) - allows me to calculate the electrical phase response - but I don't have an equivalent model for cantilever response (which is far more complex).

I just wish I could measure phase response - much of this is poking in the dark guessing at what is happening, as the tools for measurement are not available...

bye for now

David

[dlaloum]

right now I am sitting here listening to 1950's glorious mono Buddy Holly...
No comparative listening or recording...... just rocking good swinging music... music made to dance to.

[neobop]

Being an old straight wire and gain kind of guy, I wonder if the EQ itself would tend to make the carts sound the same. Is listening to the samples the same as hearing it "live"? Maybe the EQ would take it another step further from what your actual record player sounds like.
neo

[dlaloum]

Yep - I accept that this is a risk.

on the other hand the digital eq tool I am using appears to maintain a very high level of transparency... and once a difference has been identified, it should be audible without the EQ as well.

If no difference is identified once EQ'd- then it does not necessarily prove that theory, but it does provide a strong indication...

[*Scotty*]

  I can see a couple of things that are not being measured and fundamentally contribute to the sound of the phono-cartridge. The THD and the IM distortion that the cartridge produces as it traces the groove. This is not a low distortion process.
  We are also listening to the resonances excited in the cartridge body as the cantilever and stylus are accelerated by the groove modulations.
  There are an awful lot variables involved that can affect the sound we hear from the phono cartridge.
Scotty

[dlaloum]

Hi Scotty - I agree and have been considering adding these as well.

But THD and IMD will be fixed regardless of EQ or loading....  so although interesting, they are relatively academic specifications....
There will be IMD generated by the arm/cartridge interaction too, so these things will/do also involve the rest of the TT.

The test recordings are being done on a damped arm - and the damping is adjusted along with the VTF when I initially mount a cartridge for testing.

Thus far the cartridge that was most obviously improved by the damping when setting it up was the Grado Gold1... the others were too, but the Grado started to do the "grado dance" when tracking the 1k tone with the LF sweep behind it.... generating very very obvious "warbles" (let alone the sight of the cartridge almost jumping from the groove - it was really moving!)

A large part of the exercise is the elimination of psycho-acoustic cues in the amplitude and frequency domain that clue us in to which cartridge is playing.... once these cues are removed, it becomes a lot harder to hear the differences.
The ear then has to pick up on THD, IMD etc... and the ear is far less sensitive to these!

I need to experiment with my software tools and work out how easy/hard it is to measure IMD.

An additional complication is that most of my test discs are vintage - and their useage prior to entering my ownership over the last 6 months, is totally unknown. - They may have wear patterns on them that would generate THD & IMD. - Although these would impact the F/R measurements the impact would be relatively minor, but when measuring THD/IMD, the impact could be huge...

Need to work out a way of measuring this in a "trusted" manner.

more food for though (more time!)

bye for now

David

[*Scotty*]

In the old days when the test records were new their contributions to THD were a known factor and could be subtracted from the total measured distortion.  From a scientific standpoint it would nice
to have this data to fill in the picture but from a practical standpoint I am more concerned with how flat the response is and how well the cartridge will stay in the grooves,no pennies please.
There should be some differences in imaging that are unique to each cartridge and remain present even when the frequency response differences are minimized or eliminated. I hope.
Scotty

[dlaloum]

Hi Scotty,

Yes I am expecting that Imaging / seperation are a likely differentiator...

I was also toying with actually measuring (and posting) separation, which is a lot easier/simpler than THD/IMD - and also frequency related...

[bastlnut]

hallo,

i am not saying that TOTL cartridges are mandatory.
it can be a cartridge in between the 2 extremes....why does everybody immediately go only for the extremes?
further, just because one cartridge uses the same cantilever and diamond as another does not in any way meant that they will sound the same or as good.

as an example of a middle range cartridge that is a very large jump in SQ over its lesser siblings is the Dynavector XX2.
what the 17d3 does better than the DV20X is small in comparison to what the XX2 over the 17d3 does better.
in all aspects faster and more dynamic as well as detail and space.

budget and lower range cartridges do not use costlier production technics to keep the tolerances minuscule and balancing of all the parts.
the lower priced cartridges can not compete here and will simply not sound as good because of it.
it may use the best pieces but the execution is what limits its quality.

regards,
bas

[dlaloum]

I accept that principle...

But then the AT20 series were hand picked from AT15 mass production - and I have to say my AT20 is among my best balanced cartridges (in terms of inductance and resistance left/right matching) - so raising the QC and production methods can be applied equally to MM's.

The Signets are another example of this - take the same basic design, and apply the additional level of care and attention to take it to the max...

On the topic of the dynavectors - I find the 17d3 particularly interesting as a design - I note that the principles of the karat were dropped for their other models both up and down range from it.

I also note that all the "long cantilever" models (everything except the 17d3) are specified for frequency response to 20k where the 17d3 is specified to 50k...

This would bode incredibly well for transients, accurate harmonics and phase response... but one cannot judge the flavour of a recipe by the quality of its ingredients! (but it is a good start...)

In terms of the in between - my Empire MC1 is the baby brother of its near cousin the VdH/Benz MC1000 - but with an eliptical stylus and HO - at the time I purchased it in the early 90's (or was it the late 80's?...) I think it cost me around AU$1000.... so in today's $ it would be probably double that.
It is not exactly a bottom end cartridge either....

As a project looking at the differences between cartridges - I have a good selection of what I would call the "value" ranges and some of the great classics.
If I were to choose a few others that I would like to add (assuming budget was not a constraint) - I would love an ATOC9 and AT33, and perhaps a DV20x or 17D3.

Right now I have my hands full with these! (without adding more...)

But I expect that as I get through what I have and start to put up my subjective opinions as well at some point I will perhaps look to extend the selection - both up as well as down. (I don't have a straight M97xE, an AT95E or a Red Ed etc...)

bye for now

David