Quibbles and Bits

21st Century Schizoid LP

It was all the way back in the 1980’s that consumer digital audio suddenly took root in the form of the CD, and before you knew what had hit you the good old vinyl LP was being consigned to the junk pile of history – what my father-in-law used to call a GROBA (Gleaming Relic Of A Bygone Age), except that he was generally referring to his cars. But vinyl has steadfastly refused to go gentle into that good night. Here we are in 2019, and not only has the LP failed to crawl away and die, it is exhibiting an incredibly strong renaissance.

But this resurgence has not been entirely painless. The process itself is as old as the hills, and hasn’t changed significantly since the Eisenhower administration (ignoring inherently limited niche processes such as Direct Metal Mastering). You would have thought we’d have done better than that, wouldn’t you?

Günter Loibl certainly thinks so. Günter is CEO of Rebeat, an Austrian company from Tulln, near Vienna, active in various aspects of the music business. His latest venture is called HD Vinyl, an initiative that seeks to bring the process of producing and manufacturing vinyl LPs kicking and screaming into the 21st Century. I had an interesting chat with him, and he took me through the process he is busy developing. I found it quite fascinating.

The existing process for producing vinyl discs, unchanged for more than 60 years, seems almost Dickensian. It has a kind of Steampunk quality to it. There are variations, but essentially the process goes like this. First, a master is cut in a soft acetate lacquer coating on an Aluminum platter. The cut is made using a cutting stylus with a sharp edge to it – the point being that it has a significantly different shape than the stylus used for playback (if the playback stylus was the same shape, it too would cut the vinyl!). This lacquer disc is then plated with a thin coat of Silver. I say “thin”, but bear in mind that the thickness of this layer is substantially greater than the amount of groove modulation that would make an audible difference to the sound quality. This is the first of a number of “lossy” steps that impose themselves between the freshly-cut surface of the master lacquer and the finished vinyl LP on your turntable.

The next step has Nickel electroplated onto the silvered lacquer mold. When removed, this Nickel casting is referred to as a stamper, and is then coated with a thin layer of Chromium to help protect it. For a typical LP release, multiple stampers will be produced from the master lacquer. Back in the mass-production days of yore, these first-generation stampers would be referred to as a “Father” stampers, and only used to make multiple second-generation copies called “Mother” stampers, which would be the ones actually used to stamp LPs.

Finally, the stamper is used to press hot molten vinyl into the LPs that you ultimately buy and play. However, molten vinyl itself is an aggressive substance, and every individual pressing eats away a little bit at the surface of the stamper, which means that every LP stamped is of slightly poorer quality than the one before it. After a while, the stamper will have degraded sufficiently to audibly affect the sound quality of the LPs being produced. It will be up to the manager of the pressing plant to decide when that point has been reached, but as a rule of thumb as few as 500 pressings might be a reasonable limit for an audiophile LP, and perhaps 1,500 for a regular commercial release.

In summary, while this was impressive technology for the 1950’s, it is pretty clumsy by today’s standards; and quite frankly, it beggars the imagination that it is able to produce a product which engenders such a passionate, committed, and quality-conscious following. Günter Loibl thinks it is high time we came up with something better. And who would want to disagree with that?

Günter sees two primary areas in which a modern process could substantially improve upon its traditional counterpart. The first would be to reduce the number of lossy processes between cutting the lacquer and stamping the LP. And the second would be to increase the number of LPs that can be produced from a single stamper without losing quality.

One key aspect of Günter’s approach is to manufacture the stamper directly, using a stamper material that will not degrade at the rate Nickel stampers do. His choice is a ceramic material. Using a ceramic stamper, he has tentatively established that he can stamp out upward of 10,000 LPs without any measurable degradation in quality, which is a major improvement.

The second leg in the chain is to introduce the grooves directly onto the stamper itself, so that there are no lossy intermediate stages. The problem with this approach is, since this is a stamper, it is not grooves that you need but the “negative” of a groove – a ridge. You need a spiral of ridges on the stamper, so that it produces a spiral of grooves in the vinyl LPs that are stamped from it.

But you can’t write ridges onto the surface of a ceramic stamper. The best you can hope to do is start with a flat ceramic surface, and machine away everything except the ridges you want to leave behind. And this is what Günter is working on. He is developing a laser-based process that machines away the ceramic, leaving just the desired ridges behind. So just what kind of a task has he set himself? Well, if you take the best performance specs that vinyl playback has to offer – let’s simplify things and say a dynamic range of 65dB – it turns out that pickup cartridges must be responding to groove modulations down in the nanometer range. That basically means right down at the molecular level. Quite extraordinary, when you stop to think about it. This is the challenge Günter has set for himself.

While lasers can indeed be used to machine away bits of material, it is not done smoothly like a knife cutting through butter. For reasons we don’t need to go into here, laser micromachining is done using intense bursts of laser energy called pulses. In other words, material is machined away in discrete chunks. So it is important to understand what sort of finish you need from your micromachined surface, in order to develop a suitable laser machining process. Günter has examined LPs at extreme magnification, and even at the highest magnifications the surface texture of the vinyl is extremely smooth – no doubt this is at least one reason why LPs are able to sound as good as they do. So a laser machining process is needed that can generate such a smooth surface.

Günter has opted for an “ultrafast” laser for this job, and as an ex laser jock myself I do concur. This type of laser emits pulses of such infinitesimal duration that they defy description. The pulse durations are of the order of femtoseconds. By way of illustration, it takes light about 300 femtoseconds to traverse the diameter of a single human hair! Ultrafast lasers represent the absolute cutting edge (pun not intended!) of laser technology. The physics underlying such lasers is quite extraordinary, and making them is very challenging. Until very recently, they were only ever used as probe tools in even more exotic scientific experiments.

So, not only does Günter need a laser beam of the most exotic variety, but he needs to mount it in a system that can position the laser beam with nanometer accuracy, across a ceramic plate about 12” in diameter. Problems like that keep laboratories full of Intel engineers awake at nights! It is fair to say that getting an ultrafast laser working smoothly, and integrating it into its opto-mechanical platform, are going to be the thorniest problems Günter will face in developing his new technology. Once those are up and running, the rest should be much smoother sailing.

But almost as big as developing a micromachining system whose capabilities will impress NASA, is the requirement for software that will work out what the finished groove needs to look like, and provide the ‘cutting pattern’ for the laser. In effect, this is the shiny new tool that the Mastering Engineer will use. In a traditional LP cutting setup, the Mastering Engineer sits hunched intently over the cutting lathe with a selection of switches, sliders, and dials at his fingertips. In real time he is adjusting the groove spacing, the recording volume, and various other parameters, because there is no other way of doing it. He will have no idea how well – or how badly – it has all worked out until it is done. With Günter’s new technology all of this is performed at a computer workstation, before the cutting laser is even fired up, and with a lot more precision and flexibility.

Günter’s mastering software will allow the groove spacing and recording volume to be determined using algorithms, so that the result is as fully optimized as can be achieved. No grooves need be too close together so that you hear pre-echo, nor excessively far apart that the available playing time is compromised. You can optimize the settings for maximum playing time, or for maximum audio quality, or anywhere in between. You can even home in on individual regions of the LP and manually edit a part of the signal which has perhaps over-modulated slightly. And once the groove design is complete, the software can even simulate the effect of a stylus tracing its way through the finished groove, and generate the resultant music signal. Only when the mastering engineer is happy with the result does the process move on to machining the stamper. And, of course, the Mastering Engineer doesn’t actually have to be in the same building, or even on the same continent for that matter.

I wish Günter Loibl and his HD Vinyl project the very best in their endeavors. If his technology works out the way he expects it to, we will have a new LP manufacturing process which gets the quality of the stamper much closer to that of the original cutting lathe than has ever been possible up to now – even closer than Direct Metal Mastering, which has demonstrated excellent results – and will be capable of producing an almost limitless run of LPs from a single stamper without any degradation in quality.

Of course the process will have its share of skeptics, non-believers, and plain old haters. Some – after all, this is Audio we are talking about – are already lining up. LP manufacture may be a house of flaws built upon flaws, on flawed foundations, and yet it somehow works. And when it all comes together properly it works quite staggeringly well. So maybe those flaws aren’t all bad after all, and maybe by eliminating some of them we will somehow end up throwing bits of the baby out with the bathwater. Not a good visual, I know! But however it works out, the proof of the pudding will be in the eating, although I for one am delighted just to see the effort being made.

Günter tells me he is hoping to be able to produce the first actual playable LPs using the HD Vinyl system later this year. This will almost certainly not be a commercial release, but rather a demonstration of capability. He tells me that there has been great interest from within the industry, so if the technology delivers, he won’t be short of customers. If I ever get hold of a playable sample, I will be sure to report on it in Copper.