Hey Nick, really exciting stuff. I'm looking forward to meeting up with you in a week's time at Paul's place. Should be fun!

Cheers, Mani.

Hey Nick, thanks for sharing. For me, the mere fact that the sound changes with varying mobo clock speed is just incredible. It just goes to show that the 'computer audio rabbit hole' is so much deeper than anyone could have imagined.

As an aside, I've been really interested in the ADC side of things for a while now. Most (all?) studios use DAWs and I wonder how much SQ could be gained from the sorts of things we (I mean the pioneers on this forum, not me) are doing.

Mani.

Hey, next you'll be experimenting with tubes/valves in the NOS1a... "as long as it's for the better"...

Luckily, I'm working from home all day tomorrow, so will be waiting with bated breath for instructions on your new tweak. I'm not sure whether the tweak requires some mechanical feedback from the speakers to be effective, but as I don't have any feedback at all (the NOS1a 10m away in my basement in a pretty much sound-proofed room), my experience might provide you with additional info on what's going on. (Though there's no way I'll be taking the PC and NOS1a up into the main room to make a detailed comparison.)

Mani.

Ha... I haven't been on the forum for a while, just took a quick look, and was confronted with this:


Hey, you know, they're running out of Nobel Prizes up there in Sweden!

One thing that came to my mind was why not use long Blaxius cables like I don and take the PC and NOS1a down into your basement. You have everything in place for this, right? If nothing else, it will give you and idea of how things sound with no feedback to the NOS1a. Might be a useful baseline/reference for further footer investigation with the NOS1a back in situ.

Mani.

GREAT news Nick!

(I need to pass something by you, but will do this via PM later today - need to catch a flight now.)

Mani.

Totally gorgeous Kjell!

Mani.

Haha... I played this only yesterday. But it's no big coincidence because I have to play this (and 'We Are the Robots' also) at least once a week - my 5 year-old and 2 year-old sons loves these 'songs'. A few months ago I created a fictitious world called 'Planet Zog', and these two tracks are 'Zogan music'.

But what is amazing is that only yesterday I realised how much is in this track too. Nothing explicit that I can recall now, but lots of "Oh, I never heard that before."

FWIW, I usually play these tracks from 'The Mix' album. The 'We Are the Robots' track has some serious LF going on.

Mani.

Yep, happy to do that. But just a few points of clarification from my side first:


C'mon, I never said that. I said that it's clear from the plot that there's no 30Hz high pass filter applied to this particular LP, as you suggested there was (before I put up the plot). I mean, just look at the plot. Do you really see a sharp drop-off below 30Hz? I don't see it. the drop-off below 10Hz is more a feature of my turntable than anything else. Now, my LP is a Stockfisch Direct Metal Master LP. There's a ton of information on the process they use, and although they don't specifically mention it, I strongly suspect they do NOT apply a high pass filter. FWIW, my old turntable/arm/cartridge cannot play this LP at all without gross distortion.


Yes, agreed. My recording (the 16/44.1 file I posted) sounds poor in comparison to the CD.

Mani.

Oh and look here at the plot of my v2 needle drop. (By the way, no need to take a listen to this - it sounds too similar to v1.)

Why the increased DC? Same LP, turntable, phono-preamp, and ADC. Just a different digital capture method (AES into a Tascam recorder, rather than a firewire interface and PC).

I'm sure plots of my older recordings made with my previous turntable would show plenty below 20Hz, and loads of DC. Would you prefer that?

 

Mani.

And are you sure the DC should even be there in the first place? Is it really part of the signal, or an ADC artifact? Look below at the plot from a CD rip of a 10KHz test signal.

Mani.

OK, I'll try this.

But you can clearly see that the LP recording is identical in output to the CD from 10Hz upwards, i.e. there is no 30Hz high pass filter as you implied. And furthermore, the steep drop-off below 10Hz in the LP recording is a testament to how well-behaved my turntable/arm/cartridge are - little or no rumble.

If DC to 10Hz is really that important, then you have a point. Personally, I think it's the speed of the bass in the CD that makes it better, which of course is not shown by these plots.


Well, if you think 'limiting' on CDs is OK, then perhaps. But for me, it is totally, totally unnecessary - I mean, why do it?... Unless it's to have an artificial way of increasing micro details (as the RMS level is massively increased, and hence the low-level signals also).


Better than my recording, yes - there's more micro detail and the bass is tighter and faster.. Better than the LP, I'm not sure yet.


No, of course not. Interfacing to an external device probably introduces a bunch of RF reflections and noise induced jitter, which 'deaden' the sound, but which won't show up on these plots.

Overall, the plots won't tell you how something sounds. But they're great for identifying 'cheating'. In the case of the CD, having to limit at -0.5dB full scale to make it sound 'good'. Just my opinion.

Mani.

Hey Peter, technically the LP is better than the CD!!! Look below. The compression on the CD is terrible. I wondered how the CD could sound so much louder than my needle drop, even though I was going reasonably high in level. And now I know. I think this might be a good example of people being impressed by artificial loudness!

And also, where's the drop off below 30Hz on the LP? There isn't any!

Mani.

Hey Peter, thanks for the CD track. In line with Joachim's response, here's what I think:

- No stereo Yes there is, if you sit centre as I always do.
- Strange highs A little more recessed and less decay, but not 'strange' to my ears
- No bass AT ALL (This was might thought before reading your post above.) This is one of the biggest differences for me. It's not the amount of bass, or the extension that I have a problem with on my needle drop, but rather the 'speed'. On the CD, the bass starts and stops so much more quickly. It provides the rhythm for the music. On the recording it is just too slow and 'woolly'.
- No filling of the room anywhere while this track is famous for it. No issues here in my room.

This in brief. But additionally in more detail :
No flagiolettes to be heard (always a property of the better system). (Again, before I read your post above.) Certainly, the CD has more micro detail than my recording. No disagreement here.
CD shows two (dubbed) voices - LP only one. The two voices are absolutely clear in the recording, but not to the extent of the CD. Probably due to the extra micro detail on the CD.
Dead sound. Bad, poor, nothing. I'm 50% with you on this.
Watch the very last stroke on the guitar and how LP shows "a sound" while CD shows all the strings from a guitar. I totally disagree with you. It's totally clear that this is the stroke of a guitar string. Clean your ears out!

And just like Joachim, I agree that the CD is better.

HOWEVER...

You might have noticed that in all my comments referred to 'my recording' and not 'the LP'. You see, I disagree with anyone who thinks that making an accurate digital recording of an LP (a 'needle drop') is trivial. I have many ADC machines here, and I can tell you that I cannot capture a 100% accurate needle drop with any of them. The PMII is totally transparent to my ears. I can compare the original LP with an AD/DA loop within the PMII and really there is no difference. However, this AD/DA loop does not require the PMII to be interfaced with anything externally. And it is here that the problem exists. In my experience capturing the AD stream on an external device 100% accurately is next to impossible. I'm not sure if it's AES/EBU, or firewire, or the PC that is at fault but a lot is lost in this process. And this is what you're hearing on my recording.

When I'm monitoring the LP during the recording process, the sound is stunning, and most of Peter's criticisms simply do not apply. When I have some time, I will compare playing the CD (on my NOS1a) vs. playing the LP, both through my monitoring system. I am pretty confident the difference will be next to nothing.

Meanwhile, I'm quite happy actually. I've found a track that I can use to make some really valid comparisons. Also, and more importantly, I know how far the recording is from the actual LP. And I can tell you that it's a similar difference between the recording and the CD. This has really motivated me to find a better way of capturing the AD stream from the PMII.

Peter, you will see!

Mani.

Hey Peter, thanks for giving it a listen. I don't have the CD, could you send this track to me so I can compare?

Anyway, here's another needle drop of the track - everything exactly the same, but I'm just using another digital capture method:

https://www.dropbox.com/s/1x1u0d3ozvrkpci/Chris%20Jones%20-%20No%20Sanctuary%20Here%20v2.wav?dl=0

To my ears, this is better. But I'd still like to compare to the CD if possible... and then I'll be able to reply to your comments. But for now, I don't understand the "No bass AT ALL" comments - there's loads here on both versions I've posted.

Mani.

Edit: Peter, you do have HDCD switched off, right???

Hi Coen, in my case it's simple - it's what I already had. When I bought my 15KVA isolation transformer my two 5KVA balanced transformers, I specifically went over-the-top because the idea was to run the whole system from the transformers, and I wanted to keep the impedance as low as possible. But for the purpose of just feeding the PC, I totally agree that the isolation/balanced transformer needn't be very big.

Mani.