Reviewing the Furutec Demag

[Mike Lavigne]

So what are your thoughts on Gary's just completed experiment of comparing high quality analogue with an extra A/D and D/A step in the playback chain, and the results so far indicate that the group of audio enthusiasts couldn't pick the difference?

Frank

i really have no comment specifically on that experiment. but in general, they don't hold much water for me. like Bruce; i'm skeptical of any big group being particualrly perceptive.

i don't want to be critical when all that effort has been put forth. i respect that Gary is trying to investigate stuff.

 

[fas42]

Not every joe off the block picks out these differences unless you show/tell them what to listen for.

But they are not "every joe", these are supposed to be audiophiles! As Gary indicated, people didn't record results, or gave up half way through, because they were enjoying the the music too much! This is a long way from Mike saying that digital can't get "tonal texture and transparency in the mid-range" and "fullness and substance" quite right ..

Yes, a trained person can pick the difference, but we are talking about the musical message getting through.

A little thought experiment. Take the signal in Gary's experiment where it has gone through the A/D to D/A extra step, and imagine you had the best quality analogue recording setup in another room, which instantly created a new vinyl master, created an LP pressing, and put that on the identical TT that Gary was using, and then were able to switch between that feed and the original signal to the recording setup. Do you think people would or wouldn't be able to tell the difference?

Frank

 

[mep]

But they are not "every joe", these are supposed to be audiophiles! As Gary indicated, people didn't record results, or gave up half way through, because they were enjoying the the music too much! This is a long way from Mike saying that digital can't get "tonal texture and transparency in the mid-range" and "fullness and substance" quite right ..

Yes, a trained person can pick the difference, but we are talking about the musical message getting through.

A little thought experiment. Take the signal in Gary's experiment where it has gone through the A/D to D/A extra step, and imagine you had the best quality analogue recording setup in another room, which instantly created a new vinyl master, created an LP pressing, and put that on the identical TT that Gary was using, and then were able to switch between that feed and the original signal to the recording setup. Do you think people would or wouldn't be able to tell the difference?

Frank

Frank-It doesn't matter. Mike's system and room has more resolution than the system that Gary used in the room they used. And like Bruce said, the majority of people were not trained listeners. The good news is that everyone had a good time and that is all that matters. You don't solve too many problems by committee.

 

[fas42]

i'm skeptical of any big group being particualrly perceptive.

Do you mean that having a number of people in the room versus just one makes a difference to the listening experience?

Frank

 

[fas42]

Mike's system and room has more resolution than the system that Gary used in the room they used

Would you agree about that, Gary?

everyone had a good time and that is all that matters

Unfortunately, unfortunately, we are trying to do a bit more than that, which is to work out whether digital recording and playback is audibly transparent for most people ...

Frank

 

[mep]

Well Frank, it didn't end up that way. The group taken as a whole scored around 50% which is the same as flipping a coin which makes the test meaningless statistically.

 

[Mike Lavigne]

Do you mean that having a number of people in the room versus just one makes a difference to the listening experience?

Frank

is it possible for a group to be able to be effective in hearing differences in a listening test?

yes.

is it ever likely to happen?

no

there are simply so many challenges to set up a test correctly; followed by the odds of having most of the group qualified, sitting in the right spot, and being in the right mind set.

and i just do not believe that any meaningful result comes from short term listening tests.

too many varibles so almost impossible.

 

[fas42]

which makes the test meaningless statistically

No, it makes the test very meaningful. It means that people when trying to pick a difference couldn't do any better than purely guessing. Which statistically means a lot: that there wasn't a discernible difference between the two signals ...

Frank

 

[Bruce B]

Do you mean that having a number of people in the room versus just one makes a difference to the listening experience?

Frank

How do you think drugs and implant devices get approved by the FDA. I do anesthesia for a large hospital and I specifically do anesthesia for research protocols. Manufacturers don't want unhealthy patients for these protocols. The Principle Investigators choose the patients because they want every option possible to have a favorable outcome for their protocols. The failures occur when you pick patients outside the bell curve.


Gary could have had a 100% outcome if he had picked trained listeners or told the listeners how to pick out the differences. It's not rocket science. This hobby is to enjoy. There's not any enjoyment in testing, blind or not. I've do it almost every single day.

 

[fas42]

There's not any enjoyment in testing, blind or not. I've do it almost every single day.

I think the key thing is that people who say analogue is superior or different to digital frequently state that it is chalk and cheese, that it is obvious, that as soon as one has a decent system it is no effort to pick which is superior, etc, etc.

That is a lot different from "failures occur when you pick patients outside the bell curve", "trained listeners", telling "the listeners how to pick out the differences", "having most of the group qualified, sitting in the right spot, and being in the right mind set", rejecting "short term listening tests".

Frank

 

[Ron Party]

The statistics are what they are. (How's that for stating the obvious!)

But the question remains just what one can infer from the statistics. Remember, this was a hobbyist endeavor. Nothing more, nothing less. For example, others have posted on the significance that there was more than 1 testee in the room. We don't know if there was any conversation whatsoever amongst the testees during the test, or whether Gary himself said anything during the test, but, even if nothing was said we must remember the obvious, such as was pointed out by Mike re the sweet spot, to state nothing of the fact that there are unintentional, sometimes subconscious cues given by members, let alone Gary as the tester or someone like Bruce who is a trained listener, which may be in effect.

One other obvious point: this was not a traditional analog versus digital format test and, as such, even if this test would pass AES peer review, I'm wondering whether it would be proper to draw any conclusions about, as you wrote, whether analog is superior to digital or vice versa.

 

[Orb]

That's a good observation Frank. The peak is actually 9 Hz. So those waveforms in reality are mechanically induced signals.

Amir, what were the tonearms?
I can see if they have been reviewed in Hifinews and see what the accumative decay time is for their resonance if so.
However I need to point out the main resonance of most good tonearms is between 250 to 800hz(usually lower than 800hz though), with very long decay time.

Cheers
Orb

 

[Gregadd]

Well we have made a progress from no difference to the difference must be from something else. Now the question is the ball back across the net? Is it time for those who believe the demag makes a difference to demand proof from the non-believers? What would Michael Fremer say if armed with such information?

 

[Orb]

I don't get this one Orb, in my day,

tonearm/cartridge resonances were designed in to be around 4 to 10 hertz. For example, my current TT tonearm/cartridge resonance is about 8hz, thus below the rumble filter on my pre-amp. Total turntable rumble is below 60db.

Even at that, with the rumble filter in circuit, those woofers can wander about quite a bit on some records.

Tom

Not sure how Tom, because I checked a different publication that also measures vibration but not as well IMO as Paul Miller, and again these are over 150hz and up to similar numbers - bear in mind the higher figure (600 to 800 and may be high 2nd/3d modes) is more unlikely but occurs for some.

Paul Miller covered a bit of this in his June 2010 Opinions where he did a group test of reasonable priced tonearms.
Only quoting a very small part but this matches what I am seeing in two different publications:

In practice, a typical 9in alloy armtube bends at anywhere between 100-400hz with secondary bending modes, torsional and hoop modes appearing up to a few khz.
Altering the symmetry of the tube, either by varying the wall thickness and/or its overall diameter (as in the case of the SME IV, illustrated here) pushes the modes to higher frequency while an S-shaped tube distributes the peaks even further, trading a few defined modes for a complex mix.

Independant measurements do not lie
I feel pretty comfortable with what Paul Miller measures as he is pretty much well known for his measurement product, so understands IMO the factors and process involved to capture and present the relevent information; whether it be tonearms/cartridges/DACs/amps/etc.
And this seems to be backed up (talking about tonearms) by a bit more simpler measurements done by a different publication.

Cheers
Orb

 

[amirm]

Orb, I am no expert in LP technology . That said, I did read through Paul's segment: http://www.zinio.com/reader.jsp?issue=416125359&o=int&prev=si&p=92

My read is that he is talking about a secondary effect. The primary is what was stated before: which is the resonance caused by the *spring* in the cartridge combined with the mass of the tonearm. As Tom mentioned, these are in 0 to 20 Hz.

What Paul is appearing to talk about is that the tonearm itself flexes. And therefore, it creates another set of modes that are the frequencies mentioned. You can see this in the way he explains this effect with respect to the loading that the cartridge puts on the tonearm as simple weight as opposed to spring above. Since the tonearm is much stiffer than the cartridge spring, it reasons that it would have higher resonance frequency.

Take another look with this context and let me know if you disagree.

 

[Orb]

Orb, I am no expert in LP technology . That said, I did read through Paul's segment: http://www.zinio.com/reader.jsp?issue=416125359&o=int&prev=si&p=92

My read is that he is talking about a secondary effect. The primary is what was stated before: which is the resonance caused by the *spring* in the cartridge combined with the mass of the tonearm. As Tom mentioned, these are in 0 to 20 Hz.

What Paul is appearing to talk about is that the tonearm itself flexes. And therefore, it creates another set of modes that are the frequencies mentioned. You can see this in the way he explains this effect with respect to the loading that the cartridge puts on the tonearm as simple weight as opposed to spring above. Since the tonearm is much stiffer than the cartridge spring, it reasons that it would have higher resonance frequency.

Take another look with this context and let me know if you disagree.

I understand that, but it is a combination of 1st,2nd,3rd modes and how this interracts can only truly be seen by looking at the cumalitve resonant decay spectrum that relies upon the mechanical input.

As an example the Linn Akito has 2 clear resonant modes that are visible in the Jun 2010 group test.

Two clear resonant modes are visible on the cumulative decay plot, the main armtube bending at 230hz and 1.2khz, with another series at 800hz showing harmonics at 1,6khz 2.4 and 3.2khz.
Importantly these modes are very well damped, falling by 40db over the 40msec window.

The point is while I only partially quoted the opinion previously, it is these that affect the sound generated by tonearm resonances, including arm break, and why he measures these as part of the cumulative resonant decay spectrum, importantly these are affected by the cartridge

If you look at cartrige measurements the "spring" does not come into this in way discussed, specifically he focuses more on the L-R and L+R on what affects the sound, which I touched upon earlier in the demag thread.

BTW I am definitely no expert as well but I have all the investigation articles and the other articles by Paul Miller, along with comments and measurements for individual and group tests.

Just so we do not get crossed wires on semantics Paul in the article I think your talking about also says this:

If the arm moves relative to the stylus then the recovered audio is modulated adding "color", musical or otherwise.
The cumulative resonant decay plots that accompany our reviews illustrate this.....

So for a true accurate picture of resonance effect, we must consider the tonearm with cartridge included and cannot think of its own trait, still the resonant affect on sound comes back primarily to the tonearm.
However I am yet to see Paul Miller mention any type of cartridge resonance in his discussions or measurements (even for cartridges) but I appreciate I may had missed them.

The closest I see to this is the following but then the main operation seems to be vibration linking to tonearm:

All seasoned vinyl fans understand the need to match cartridge compliance to the arm's effective mass to avoid resonance with warped LPs, at the other extreme, subsonic groove detail...
In truth , the little beggars bend,ripple,twist and even expand and contract in response to noise (vibrations) from the body of the cartridge.

I do appreciate we may be crossing semantics and different focus on where the primary resonance (or alternatively it is vibration noise instead) originates from or should be the focus-affecting the sound.
Where he does say:

The natural frequency of the arm is proportional to its mass and stiffness but is readily "tuned" by your choice of cartridge and compliance of its mounting to the deck.

But for his parameters relating to cartridges and their impact on sound or performance (March 2011), resonance is not one of them.

Cheers
Orb

 

[mep]

So Paul wrote his own software and threw out a few tantalizing tidbits about secondary resonance effects. Tom was right that tonearms/cartridges were designed to have a combined resonance that is lower than most speakers can go except for the Bass Pig. 8Hz is a good example. Amir is right that the focus of this short article (unless I'm missing some pages) is about secondary resonances. I personally don't have any woofers flapping in the breeze of resonances.

 

[garylkoh]

Mike's system and room has more resolution than the system that Gary used in the room they used.

Would you agree about that, Gary?

Yes and no...... Mike's system and room has more resolution, but it would not be suitable for the session. The Genesis speakers are designed for a very wide sweet spot, and for the evening, I had set them up so that the sweet spot would be even larger. We set up 30 chairs in a 5-wide by 6-deep configuration. Probably 3 seats were "sweet spot" - the middle chairs in rows 3 to 6 (best on row 3).

Two seats were bad - the left-most and right-most seats on the front row (nobody occupied those seats). The front row was probably too close (also unoccupied until some late-comers arrived). The left-most and right-most seats on the second row was sub-optimal, but every other seat was sufficiently good for the purpose of this exercise.

The piano on my piano-scale diagnostic sounded the same at 28 seats. They all had a soundstage and quite precise pin-point imaging without having to sit in the 3 "sweet spot" seats.

Unfortunately, unfortunately, we are trying to do a bit more than that, which is to work out whether digital recording and playback is audibly transparent for most people ...

Frank

Actually, we were trying to do less than that. We worked out that inserting a A/D/A loop was audibly transparent for most people. There's more work to do before we can do the digital recording and playback. Bruce and I chatted briefly about that, but thought that the logistics was too hard. You have to remember that we are doing this outside our day-jobs and night-jobs

 

[garylkoh]

Gary could have had a 100% outcome if he had picked trained listeners or told the listeners how to pick out the differences. It's not rocket science. This hobby is to enjoy. There's not any enjoyment in testing, blind or not. I've do it almost every single day.

Correct! Bruce gave a brief about what to listen for when the EXCO were at my place. The two listeners who got the highest scores focussed on just a single aspect. One picked soundstage, and correctly identified 6/6 a wider soundstage without the A/D/A loop. The two mono recordings did not have a soundstage to listen to, and he got both wrong. The other cuts he couldn't tell a difference and guessed for 8/11. The other listener picked the treble - and got 9/11.

I think that the rest of the audience might have enjoyed the music more.....

 

[garylkoh]

The statistics are what they are. (How's that for stating the obvious!)

But the question remains just what one can infer from the statistics. Remember, this was a hobbyist endeavor. Nothing more, nothing less. For example, others have posted on the significance that there was more than 1 testee in the room. We don't know if there was any conversation whatsoever amongst the testees during the test, or whether Gary himself said anything during the test, but, even if nothing was said we must remember the obvious, such as was pointed out by Mike re the sweet spot, to state nothing of the fact that there are unintentional, sometimes subconscious cues given by members, let alone Gary as the tester or someone like Bruce who is a trained listener, which may be in effect.

One other obvious point: this was not a traditional analog versus digital format test and, as such, even if this test would pass AES peer review, I'm wondering whether it would be proper to draw any conclusions about, as you wrote, whether analog is superior to digital or vice versa.

Both Bruce and I were behind the acoustic panel most of the time, and neither of us said anything to influence the protocol. The only thing I did was to flip the input enough times so that people wouldn't be able to guess whether I started out with straight-thru or A/D/A loop. I mostly described the LP that I would be playing, and let the audience trust their own ears.