MoFi controversy

In the other side those woofers goes down to 16hz and common sense ( not with technical foundation. ) tells me that it does not play way higher than its crossover design at 450 and as a fact still have a first order filter through the in series inductor.

@rauliruegas My woofers can go that low too. They are crossed over at 500Hz and have significant output well above 1500Hz; I would expect yours do too. If I were you I'd be looking at a better quality capacitor rather than simply removing them.

@rauliruegas

After what I posted here : do you still think that I must return the caps to the woofers crossover?

As @theaudioamp pointed out, some music may sound alright but other music may not; its likely the speakers will be less neutral due to distortion and frequency response variation. Since they are not rolling off correctly per the design of the speaker there will be too much energy in the range above the normal operation of the woofers.

Is the intention of suit to drive Mofi out of business?

IMO, someone with enough excess time and money is imposing a lawsuit because they can.

Which kind of problems could be to appear in the woofer or amps

@rauliruegas 

Many woofers break up at higher frequencies. The breakups are great in a blues guitar amps but they really aren’t good for hifi. Breakups are portions of the cone that are no longer acting as a piston with the rest of the cone. Its like a resonance but doesn’t show up in the impedance curve. This is one reason ’full range’ drivers don’t work all that well unless crossed over.

My last move was to take out the caps in the speaker woofers crossover and left only the pure silver ribbon inductor and I will try to do the same with the speaker tweeter silk dome. At the end the best cap is no cap at all.

@rauliruegas One important function of the crossover is to prevent the driver from operating out of its proper region. Depending on the driver this could mean that without those caps you might have more breakups audible- increasing distortion. I would do this with care if I were you.

After Ampex/Quantegy went out of business, I had questions whether I could tolerate the sound of new tape... some of it sounds worse than PCM recording - just my opinion.

@moonwatcher Tape does not have much of a 'sound'. Tape technology does. In case you are not aware, new tape is being made by ATR Magnetics https://www.atrtape.com/

-and it 'sounds' just fine; every bit as good as the Ampex/Quantegy. But of course, any time you change the tape you're recording with the bias on the record head should be optimized for the tape or it won't 'sound' right. So it might sound bright or otherwise unpleasant if the bias is off. If you've run into this and think its the tape, its really your machine not being set up right.

Beyond that any properly functioning tape machine will express a bit of 3rd harmonic at or near 0VU (when properly calibrated) which adds a bit of warmth to the sound.

I made the same mistake FWIW...

@blisshifi I'm sure they work fine! As with all things, so much in digital depends on execution. I would not expect any greater dynamic range if you are dealing with sources that use compression to begin with. But you might have greater resolution. 

Anyway, it seems like one of their advantages is process, apart from custom made Tim de Paravicini analog paths (probably preamps, amps and modifications to the lathe?). They are able to cut an acetate, have it plated and pressed and listen to it, as one would a regular LP.

@whart FWIW dept.: the correct term is 'lacquer'. Acetate is the paper material used in early reel to reel tape, as opposed to polyester. It breaks easily but does not stretch and sheds far less that polyester tape. So if you work with such a tape for a remastering project, it typically won't need baking.

The rep also stated that they would even occasionally go to the trouble of ’baking’ the master to improve the transfer ( which at the time i thought as odd).

@daveyf Baking the tape is done to chase water molecules out of the polyester tape backing. This is done to prevent shedding of the oxide and is a good practice when handling older tapes from the 1970s and on. Its done at a lower temperature and works best if you are patient. Anecdotally we mastered a reissue of a folk album once and had access to the master tape which was stored in the musician’s attic- which is an ideal place to store tape long term as it tends to be hotter and dryer in attics. The master was made in the early 1970s and was in excellent condition. If you’ve ever wondered how cassettes could hold up over 20 years when stored in a car its a similar process.

That is totally false. CD has greater dynamic range in theory and in practice.

Why many THINK that it is the opposite is just of the reason you told.

When LP is the analog equivalent with the digital MP3 but even worse in some cases. With that I mean that LP is in data terms a lossy format and worse is it adds random click and pops that were not in the source so it is worse than MP3 that do not add those artifacts.

Do some of the mentioned steps add any sound quality:

• Lacquer cutting does it add Sound quality?
• Plating and additional plating (father, mother..) does it add Sound quality?
• Pressing when first LP is different than the last when the stampers is worn out. does it add Sound quality?
• Vinyl compound different is more or less noisy does it add Sound quality?
• Profile of the stampers flat profile does it add Sound quality?
• More or less excentrisy does it add Sound quality?
• Better TT with more or less wow and flutter does it add Sound quality?
• Better tone arm does it add Sound quality?
• Better cartridge does it add Sound quality?
• Using better canteliver does it add Sound quality?
• Better stylus shape does it add Sound quality?
• Uni-din, Löfgren A/B, Bergwall and so on does it add Sound quality?
• Better adjusted SRA, anti scate, VTA, zenith and so on does it add Sound quality?

No NOTHING of the above does add Sound quality!

But what vinyl production and playback does is it just try to do each point with as little harm as possible in other words all steps tries to lose as little sound quality as they possible can so we see all is lossy and add clicks and pops.

 

With all that said when we hold a LP in our hands it is a physical copy protection when it is not possible to go back by digitalization, to the digital source that the LP were produced from when it is NOT lossless.

 

So you often have to go back to the label and request such a file.

When label know that above and LP need all they can get when it is lossy. Then often the digital files that are used for lacquer cutting is allowed from the labels that supply a less or not at all compressed digital file.

 

So many comparisons between CD and LP is not appels to appels when they are two different files one more compressed than the other (but yes it is still the same mastering engineer and so on).

And on the other hand the digital media (CD and the others) there is no problem to do a bit perfect copy so the label don’t want us to have to good sound quality wise copy from them (otherwise also it would be harder to sell a reissue down the road).

 

So in theory and in PRACTICE CD are better than LP in every possible way. And many comparisons that shows otherwise is flawed when the one that compare thinks that they compared the same version when it were the same mastering engineer.. And not knowing that LP pressing plants are getting a more dynamic copy of that digital file than the CD pressing plants got.

(As a side note regarding LP. Is it is satisfying to get better sound quality when going from spherical stylus to line contact. But most of us thinks naturally that wow we have increased the sound quality, now we have not we are only having and doing LESS losses than we had before. The degraded sound quality were always in the grooves. And we can’t enhance that in any way just to preserve it as good as possible.)

I should address this as this post contains a variety of misconceptions about the LP.

I was correct about dynamic range of the LP. It can be wider than the digital release because the digital release is usually compressed. There’s no need for compression in the LP. Whether an uncompressed digital source file was used for the LP mastering is another matter entirely and depends largely on the producer of the project.

This might come as a surprise but the lacquers cut by the cutter head are dead silent and easily rival Redbook for noise floor. If you play such a lacquer, assuming that the cutter was set up properly the electronics to play it back will be the noise floor. The surface noise of LPs come in during the pressing process, but ticks and pops are usually not a part of that, even if the pressing was done at a less than stellar pressing plant. FWIW Acoustic Sounds has their own pressing plant called QRP in Salinas, KS. They sorted out that by damping vibration in the pressing machines as the vinyl cools that they can cut surface noise. By my measurements it can be up to 20dB which came as a bit of a shock. We did a project through them a few years back and the noise floor was so low we were wondering if the stylus was in the groove when the music burst from the speakers. In a nutshell while obviously not all LPs are this quiet, to assume that because one is noisy that such represents the format isn’t logical.

When you make an LP, typically you have to sign off on a test pressing. Nearly every LP made has a test made to insure the integrity of the stamper. This means ticks and pops can cause rejection of the stamper (which usually means the project has to be remastered) but if the pressing house is any good this is a rarity.

Due to endemic poor phono preamp design during the 1970s and 80s, ticks and pops are often the result of the phono section (due to poor high frequency overload margins) rather than the LPs themselves unless the LP has seen poor treatment (CDs treated poorly don’t fair so well either...). The phono preamp I use has plenty of HF overload margin so as a result I’m very used to playing entire sides without any ticks or pops at all. I’m often asked if I’m playing CDs at shows on this account- people are so used to ticks and pops they just assume its part of the LP experience when its often a symptom of poor phono preamp design.

FWIW since the inception of the stereo LP in the 1950s , its had bandwidth well past 40KHz. Not that there’s anything up there, but just to test this I’ve cut test signals at those frequencies and played them back on the old SL1200 we used to see if a regular pickup could handle what we were cutting. The idea of the LP being a lossy format is simply false. By comparison reel to reel tape of any track width and speed has less bandwidth, higher distortion and reduced noise floor.

My recommendation to anyone thinking otherwise is to spend some time with a mastering lathe and work it out for yourself. Doing so caused a lot of impressions I had about the LP to die a horrible death. Again as I stated earlier, the dynamic range limitations occur in playback, not record. This too is where most of the measured distortion occurs. An LP mastering system typically runs 30dB of feedback at all frequencies so is actually a very low distortion system.

People get such variable results from LPs, since some are good at tonearm setup and have better phono sections and others are terrible at it while others are somewhere in between.

IMO/IME if there is a particular advantage of digital is this latter bit, since generally you can do a plug and play with good digital equipment and get excellent results. That’s a lot harder with analog; with all the misconceptions and outright misinformation surrounding it this should be no surprise.

Now one might think since I’m presenting this information that I’m a particular fan of the LP. I do have to admit that now that I understand the mastering process from hands on that I do have more appreciation for the format. But I’ve got no problem with digital; the big issue for me is the delivery- how do you get it into the home? CDs are fine but if they get in trouble there’s nothing you can do but extract it from the player and play something else. With the LP if a crystal of sugar or other foreign object has caused the stylus to skip you can remove it and proceed.

Most lathes preview the a digital file which allows the lathe to cut within its safe parameters. All analog cuts that turn out great might be "minor miracles".  I'm sure @atmasphere can explain the preview process better. 

The preview process is simply looking for the quiet and loud spots so you can speed up the lead screws that drive the cutter head so as to prevent over-cutting (overwriteing a prior groove) and also so as to take advantage of space that is possible when the music is quiet.

The 'preview' can be done several ways. One way if you have a reel to reel machine is to place a tape head about 2 seconds upstream from the playback head- this head is often referred to as a 'digital preview' head because its output is used to digitally create the correct speed for the motor driving the lead screws. The Compucut system made in the 1980s used this technique.

You can also create speed information by playing the project first and then playing the speed file back while synchronized with the actual audio. That is the technique we used.

There are other techniques as well.

The reason its harder to do an analog master tape is the tape does not have normalization like is often found with digital source files. Its important to understand that an LP mastering lathe is almost impossible to overload. IOW the cutter head can easily cut grooves that no cartridge has a hope of tracking. So you have to be careful to not exceed playback limits. Especially if you are not using compressors or limiters this can be tricky and may require a bit of engineering time working with the project doing test cuts to see how problem areas work out.

FWIW dept:

I ran an LP mastering operation for about 10 years. LPs get mastered from digital source files all the time. The trick is to make sure that the file you're working with does not contain the DSP stuff that the digital release file does. So you often have to go back to the label and request such a file. The reason is simple: digital release files are compressed since there is an expectation they will be played in a car.

For this reason the LP frequently has greater dynamic range than the CD (or other digital format). About the only way you're going to get that is if you get an LP that was mastered without the compression.

For those that argue that digital has greater dynamic range, why would anyone do that, that sort of thing; in theory yes in practice no.

Also FWIW dept,: master tapes from 50 years ago may no longer exist or might be in dreadful condition. Labels are not always that great about master tape storage. Years ago we tried to reissue a title that was on CD to LP; turned the label had recorded over the master tape for use on another project...