Reviewing the Furutec Demag

[Orb]

Well I pulled the 2 original files into my workstation, lined them up sample to sample, inverted phase on one of the tracks and got an overall RMS value of -58dB That's pretty significant.
Now the problem I ran into is that within 45-50 seconds, the samples were no longer aligned. I would contribute that to turntable speed fluctuation. You can hear it waivering as the samples would get further and further apart and the sound would get louder and louder.
But as I stated earlier, when the samples DO line up, the difference is quite loud.

And as I stated above, i've tried this with CD/SACD and could not hear or see a difference when comparing files.

Inverted phase file

Bruce,
thanks for the clarification, and also thanks to you and Gary/Amir/etc who took the time to do recordings and listen-analyse the files.

I am not too surprised because what seems to have happened here is from what I remember pretty similar in characteristic to those recordings on Stereophile forum.
What never was considered was this; that the Furutech demag may be doing something else and not necessarily related to magnetism (yes some can argue their narrative is this but the point is are these devices actually having an effect not necessarily if the marketing is correct).
But lets be honest no-one I know has dismantled or actually used various test monitoring equipment on these demag devices.

One area that seems plausible is that the static charge-buildup is somehow affected, which is an area the better polymer-none black carbon LPs also excel.

The real key would also be trying the Paul Miller measurement for cartridges where he measures (L+R) and (L-R), to see if whatever is the cause is affecting this (post #129).
But honestly this is beyond the point of what is intended in the thread; which was show something was happening with the use of the demag and behaviour of LPs-cartridges.
And currently looks like there is from what I am reading about the test here (appreciate this is nothing conclusive or scientific but is of interest).

Cheers
Orb

 

[Gregadd]

Loyd Walker of Walker tt and Walker talismanm fame thinks it might be static electricity. Ironically Fururtech makes a Destat. So they could be compared to see if the effect is is similar or identical.

 

[amirm]

I went back and reread this thread from the start. I forgot greg started this food fight. What is the point to this whole thread??

Greg stated it pretty early on: wanted to see how I would respond to the claims made. It was more of a psychology play than audio discussion but I took it on and here we are!

http://www.whatsbestforum.com/showt...he-Furutec-Demag&p=36838&viewfull=1#post36838

 

[Mike Lavigne]

Well I pulled the 2 original files into my workstation, lined them up sample to sample, inverted phase on one of the tracks and got an overall RMS value of -58dB That's pretty significant.
Now the problem I ran into is that within 45-50 seconds, the samples were no longer aligned. I would contribute that to turntable speed fluctuation. You can hear it waivering as the samples would get further and further apart and the sound would get louder and louder.
But as I stated earlier, when the samples DO line up, the difference is quite loud.

And as I stated above, i've tried this with CD/SACD and could not hear or see a difference when comparing files.

Inverted phase file

Bruce,

when you did the samples from the Winston Ma session with and without the tourmaline gun; was there that speed issue? i don't recall you mentioning that.

 

[Bruce B]

Bruce,

when you did the samples from the Winston Ma session with and without the tourmaline gun; was there that speed issue? i don't recall you mentioning that.

I didn't do a null test with those files. I pulled those files just now into the workstation and at 1 minute the files were off 0.15 sec. I think that's pretty good.

 

[Mike Lavigne]

I didn't do a null test with those files. I pulled those files just now into the workstation and at 1 minute the files were off 0.15 sec. I think that's pretty good.

and how did that compare to the samples from Gary?

 

[Bruce B]

and how did that compare to the samples from Gary?

after 1 minute, the other files were off 0.93 sec.

 

[amirm]

OK, here is some data. As Mr. Spock would say, "Fascinating!"

Let's look at the waveforms first. Here, I am comparing only the one channel from each file with the top one being #2 and the bottom, #1. I had to cut the start of the latter to get them to align:

Looks like the #2 has deeper hills and valleys.....

Here is where it gets fascinating. What you see above is NOT the actual notes in the music. But rather, seems to be another set of Piano notes bleeding/printing-through! It is extremely faint and what you see is magnified many times. I heard the same thing in Bruce's samples before. Is there really this much crosstalk?

Once amplified, we can then listen to each track, noting the differences. What I hear in the #2 track is somewhat warmer sound but also, a clear mechanical rumble. The other is thinner in character but is somewhat devoid of that. I guess no matter how expensive or fancy the turntable, some amount of motor noise, etc seems to be bleeding through.

I let you listen to each for yourself:

http://amir-views.com/downloads/Start1.wav
http://amir-views.com/downloads/Start2.wav

Let me know what differences you hear.

BTW, the reason I pay attention to low level detail is that that is the area that is likely impacted the most.

 

[amirm]

Forgot to say, they are mono files. And one plays in one channel, the other, in the other. So hopefully your ears are symmetrical .

Also, right click on them and save them to your hard disk and then play there. I just tried streaming them from my server and it glitches causing artifacts that are not there.

The audio files are just 2-3 seconds long making it easy to go back and forth. Just double-click on one file and then other to switch.

 

[Bruce B]

Thanks Amir... what program are you using? When importing, did the workstation change the bit-depth to 32bit-float?

The faint notes are probably tape print-thru or pre-echo that occured because the tape wasn't wound tails-out when transferred to vinyl.

 

[amirm]

I am without my good tools while at Microsoft and suffer at the hands of Audacity. And yes, it converts everything internally to 32-bit float by default which I thought was good for the level increase I applied. It also supports fixed point 16 and 24.

And oh yes. Somehow I had forgotten the source was a tape here .

 

[garylkoh]

This is fascinating..... did you do your processing on the 44.1 files or the 96 files? I used the free SoX resampler, so I don't know if that may substantially degrade things.

The last thing I would have expected would be that the de-mag slows down or speeds up the music. If in 1 min, the offset is 0.93sec in my files, that's pretty significant! Can that difference be attributed to the turntable? It uses a 3-phase AC motor and crystal-regenerated 3-phase AC.

No wonder I such strange results when I tried using Audio Diffmaker if the speed between one sample and the next was different.

 

[mep]

Gary-I too am surprised that your table would vary in speed by that much in the space of one minute.

 

[Gregadd]

Perhaps we need a magnetic turntable bearing?

 

[fas42]

No wonder I such strange results when I tried using Audio Diffmaker if the speed between one sample and the next was different.

The level of sub-sonic signal to me is remarkable high, is that typical for high end TT? It also also varies dramatically between the samples, I guess depending on precisely where the LP is positioned on the platter -- is that the case?

Frank

 

[amirm]

Well, the speed difference can be explained. If the LP is magnetized, it will create an EMF field which will fight the motor, causing speed variations.....

 

[mep]

Perhaps we need a magnetic turntable bearing?

They certianly are out there to be had.

 

[garylkoh]

So am I. For this trial, I used a 1kHz tone on the Analogue Productions Ultimate Test Disc to check the speed of the t/t, and the detected tone at the output of the phono stage was 1000.0kHz and it doesn't vary. It's easy to check because when you use your finger to drag the edge of the platter, only a very, very light touch is needed to bring the speed down.

 

[Mike Lavigne]

This is fascinating..... did you do your processing on the 44.1 files or the 96 files? I used the free SoX resampler, so I don't know if that may substantially degrade things.

The last thing I would have expected would be that the de-mag slows down or speeds up the music. If in 1 min, the offset is 0.93sec in my files, that's pretty significant! Can that difference be attributed to the turntable? It uses a 3-phase AC motor and crystal-regenerated 3-phase AC.

No wonder I such strange results when I tried using Audio Diffmaker if the speed between one sample and the next was different.

i think to interpret the significance of the off-set you would need to do some sets of measurements without the de-mag'ing......and different tt's. some varibility may be more typical than you think.

the Rockport was .15 seconds off after 60 seconds. why? who knows?

60.00/.15=400

33.3333/400=.083333 of variance for the Rockport.

60.00/.93=64.51

33.3333/64.51=.5167 of variance for the tt used Thursday night.

this was just one measurement for each, so who knows how it might vary.

in any case, i doubt anyone would hear the variance on the Rockport.

i think if you did this measurement on multiple tt's that high torque direct drive tt's would measure much better than belt driven tt's.

i strongly question that the de-maging has anything to do with the variance.

 

[mep]

Well, the speed difference can be explained. If the LP is magnetized, it will create an EMF field which will fight the motor, causing speed variations.....

Amir-Your graphs were very interesting. Are you now a believer that something is going on with the demag process?