Reviewing the Furutec Demag

[Gregadd]

I think we forget the tt is constantly hunting for the right speed.

 

[mep]

I think we forget the tt is constantly hunting for the right speed.

Not true for belt driven tables with no servo attached.

 

[amirm]

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.

They were all done at 44.1 Khz. But I just repeated the test at 96 KHz. Everything is the same as far as difference except that both tracks now seem a bit warmer.

 

[Mike Lavigne]

Not true for belt driven tables with no servo attached.

you cannot generalize about servo's, there are cheap servo's on low end dd tt's; then there are servo's on uber tt's. then there are open and closed loop servo's.

you gotta listen (or maybe measure) to judge them.

 

[amirm]

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

Without a "control" as Frank mentioned (and I said repeatedly at the beginning) there is no conclusion to draw on that front. We don't know that the act of manipulating the LP or recording multiple times would not naturally generate these variations. I will say that there is a difference though. So either LPs are unreliable from play to play or the device made a difference.

What thing I am sure of though: LP is not for me . How do you guys put up with all the clicks and clacks? It drove me nuts analyzing these files. I am so used to quietness in digital. And if the mechanical warble is unrelated to using the device, then that is another thing that would bother me. I think I need hazard pay, having had to listen for 3 hours to these artifacts .

 

[amirm]

"And one more thing...."

Digital seems to be a perfectly good tool to analyze such things. Having samples frozen in time is a great tool to measure things objectively. And surely if that is the difference normally heard, digital was able to capture it all. Put another way, digital's resolving power seems to match and exceed that of the DeMag!!! Take that Greg.

 

[Mike Lavigne]

"And one more thing...."

Digital seems to be a perfectly good tool to analyze such things. Having samples frozen in time is a great tool to measure things objectively. And surely if that is the difference normally heard, digital was able to capture it all. Put another way, digital's resolving power seems to match and exceed that of the DeMag!!! Take that Greg.

i have a different perspective.

digital is very good at timing and making nicely spaced samples. and all the graphs are cool and helpful to analyze stuff.

OTOH 'capture it all'. hardly.

 

[Gregadd]

"And one more thing...."

Digital seems to be a perfectly good tool to analyze such things. Having samples frozen in time is a great tool to measure things objectively. And surely if that is the difference normally heard, digital was able to capture it all. Put another way, digital's resolving power seems to match and exceed that of the DeMag!!! Take that Greg.

So we have left demag and returned to the vinyl /cd food fight.
HD resolves better than regular tv. That's good for those young actresses. OTOH...

 

[Gregadd]

Not true for belt driven tables with no servo attached.

I read somewhere that speed variations can be caused as the belts drives the platter it expands and contracts. As the belt pulls on the platter it expands and contracts.

 

[Gregadd]

Back to the point of this thread. Is not this better than name calling?

 

[garylkoh]

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

That got me curious... so I checked a few files I had. The Jun Fukamachi that was recorded on the Rockport had 20Hz at -30dB, so did the files I recorded on the Roksan, and on a 3rd t/t the SOTA Millennia it was also -30dB. So, may be it's typical for even high-end TT?? Another measurement that the digital folks have us analog folk over a barrel

 

[garylkoh]

Back to the point of this thread. Is not this better than name calling?

Greg, I think that you got a good and civil discussion going.

So, back to the point, if I were to review a demag device (not the Furutec) I would say that it made a positive difference that we thought we heard sighted and live. It made a difference that could be captured on digital - resulting in waveforms that had deeper valleys and higher hills - which might be translated to greater dynamics?

Did it make a difference that we could hear in the digital capture? I think that the jury is still out. Could anybody hear a difference in the two tracks? I couldn't..... not in my office background music system, but once I get my system back next week, I'll have another listen.

Since Mike doesn't seem to be in a hurry to get his demagnetizer back, I might do some more experiments if I can find some time. I might even try demagnetizing the tone arm cable.

 

[fas42]

Okay, I have just been looking around a bit more at the Ella files posted by Gary, the 44kHz beasties, scrutinising the left track only, in Audacity. There are funnies at the start, as seen in the extracts by Amir, but further down things settle down for the high level sections. There is a speed variation, slip, whatever, between the two, but provided you slide the 2nd sample around to match the 1st, you can see what's going on. In most areas there is remarkable consistency, at high levels, almost perfect mirror images in the waveform. But, there is one very interesting area, at 43.67-43.68 secs in, from the start of sample 1. This is an area of high frequency stuff, up to 20kHz, at about 50-60dB down from the peak. And the differences between the files here are quite dramatic, you can definitely see the variation in the output of the treble harmonics.

People who have Audacity might like to look here: I'm having trouble getting big images attached to a post, so Amir might like to help out ...

Frank

 

[garylkoh]

Tom-I get you. This was done in the middle of a session with a completely different objective. When I get my system put back together, I'll try to do some more comprehensive testing. Including, as you mentioned, playing a track, resting for 2 minutes, and then playing the same track again. Then, I'll flip the record over, play a track, demag, and then play the same track again. This should give us some more data.

Also, do the above, but an album with clear vinyl. There are also the reviewer sets of Clarity black and clear vinyl that MikeL so kindly provided.

But seriously, is the horse really already dead?

 

[amirm]

So, back to the point, if I were to review a demag device (not the Furutec) I would say that it made a positive difference that we thought we heard sighted and live. It made a difference that could be captured on digital - resulting in waveforms that had deeper valleys and higher hills - which might be translated to greater dynamics?

Let's be careful about that. That part of the segment was amplified 35+ db and then the graph enlarged again. The signals are barely riding over residual noise.

Did it make a difference that we could hear in the digital capture? I think that the jury is still out. Could anybody hear a difference in the two tracks? I couldn't..... not in my office background music system, but once I get my system back next week, I'll have another listen.

I thought of another experiment to make this comparison simpler. I took the first four piano notes from the first file and appended the same from the second (after trimming the header I used earlier).

Here is the file: http://amir-views.com/downloads/ShortCompare.wav

As Alice said in Wonderland, the case becomes "curiouser and curiouser"! 'Cause on my laptop, I can hear the difference. Listen for the five notes, then there is a glitch and the other version plays the same. I don't want to bias you with what I heard.

 

[amirm]

But seriously, is the horse really already dead?

Unless I am mistaken, I think we have moved on from DeMag to learning about characteristics of LP system. It sure would be fascinating to find audible differences from play to play. Such differences would cast doubt on many tweaks done in analog domain. After all, if you can't reliably repeat the same experiment, then the tweaks may not be at play at all.

So I for one would love to see 5 captures of the same LP. And then may be raising the temps a bit and repeating, etc. We may be breaking new ground here in discovering how this medium works.

 

[fas42]

Interesting stuff. Looking again at the Ella files there appears to be an arm/cartridge resonance at around 8Hz, this is the sub-sonic signal I mentioned earlier. It appears all the way through the track, and is only 30-40dB down. No wonder woofer cones sometimes do a merry dance!

Okay, got screen capture working better, so here is this behaviour:



Frank

 

[cjfrbw]

I would not be surprised if LP playback were different from play to play. It is a physical medium, and any slight physical, ionic, temperature, etc.etc. difference could be reflected in sound. Some guys speculate that the grooves "melt" slightly from the heat and pressure of the stylus, and some won't play an LP twice over a 24 hour period because of this.

However, it comes down to the same perceptual quandary, are you just hearing a difference, but not necessarily an improvement, just a variation. Many variations are going to be equally good, or not enough different to be meaningful one way or the other. One probably just needs to accept this variation as part of the "error" envelope of vinyl playback and not try to make LP more precise than it is.

I don't really give a rat's ass if the deguass/demag works or not, it is not worth the effort to prove or find out for what appears to be a minor testimonial difference, much less purchase an expensive piece of equipment over it. Money and time better spent in other pursuits. If I were going to add another OC disorder ritual to my LP playing, this would not be the one.

 

[fas42]

I mentioned earlier about an area of significant variation between take 1 and 2 of the Ella files at 43.68 secs: here is a view of that piece in Audacity. It may not appear that dramatic, but note particularly the greater level of high frequency "wiggles" in the 1st sample:



Frank

 

[Orb]

Unless I am mistaken, I think we have moved on from DeMag to learning about characteristics of LP system. It sure would be fascinating to find audible differences from play to play. Such differences would cast doubt on many tweaks done in analog domain. After all, if you can't reliably repeat the same experiment, then the tweaks may not be at play at all.

So I for one would love to see 5 captures of the same LP. And then may be raising the temps a bit and repeating, etc. We may be breaking new ground here in discovering how this medium works.

LOL now we are hitting what I said would happen in the thread
Really if you are doing that you should have 2 identical LPs but critically (and this is so important), they must either be modern high quality pressing or one of the super cut high quality of the past.
Keep one as a control and one used with demag.
I would be surprised if the control one changes so much each play that the difference is that severe to be as audible as the "demag" process.

One way to put it, I read that the demag when it was played at the time was noticably different, did you not play the LP several times before demag and if so surely you would had noticed the same level of change each time it was played?
In other words if replaying causes differences, then it should be as noticable as demag everytime you cue that LP

But looking forward to how this progresses.
If not using two identical LPs, then would be interesting to compare a good quality pressed LP to an average LP with both played multiple times and also demag - will the LP behaviour characteristics be the same.
In all of these I am not talking about the best polymer without carbon black pressed LPs, as I am not sure the demag does anything really for those.

Cheers
Orb