Getting to know, Circuits, Parts, and Concepts, that can assist audio reproduction.

[Batty]

3 minutes ago, aussievintage said:

 

oh and btw, coax cables are transmission lines  

So is my sub woofer

 

[stereo coffee]

The restriction of 20-20khz began largely self imposed by the digital era.  This was the price we paid for the sampling at 44.1khz and compliance with the Nyquist -Shannon theorem. Moreover it was the size of disc chosen, and time limitation of disc length before that,  which chose the 44.1khz sampling rate.  What we awkwardly also got,  was steep filtering at the Nyquist point, of just below half the sampling frequency.

 

One just has to read the on going dedication and interest to analog ( tape /phono ) to know something is missing in digital, never the less, I would be the first to agree it is very good at what it does. I think the most incredible moment in digital history was missed ( but could return )  in the form of moving away from PCM ,  instead to companded predictive delta modulation. We might then hear what digital was capable of, the DBX700 though was tied to VHS tape, and was its downfall, but the specifications were amazing.  http://www.technofileonline.com/texts/dbx700recorder86.html

 

Embracing that many pieces of source equipment other than digital has frequency response much higher, we can see trend to perhaps impose the 1983 digital era sound, by not thinking any higher.

 

A Denon 103 cartridge as example has specification here to 45Khz

 

[Steffen]

22 minutes ago, stereo coffee said:

The restriction of 20-20khz began largely self imposed by the digital era.  This was the price we paid for the sampling at 44.1khz and compliance with the Nyquist -Shannon theorem. Moreover it was the size of disc chosen, and time limitation of disc length before that,  which chose the 44.1khz sampling rate. 

 

 

Let’s put the horse before the cart, shall we? The restriction of 20Hz-20kHz began much earlier, in the deep, dark past of human evolution. The sampling rate of 44.1kHz was chosen to cover our hearing range (+10% for good measure). The sampling theorem is a discovered fact about the natural world, it’s not something to be complied with. Nature doesn’t care what we find out about it, or how we make use of the knowledge.

 

A higher value could have been chosen for the sampling rate, requiring a shorter play time (even down to LP length), but this was considered unnecessary and wasteful.

 

BTW, the enhanced RIAA curve forcibly rolls off frequencies above 20kHz (with the original RIAA curve those would have been raised boundless during recording), not sure how useful 45kHz phono cartridges would be.

[davewantsmoore]

18 hours ago, andyr said:

So the ideal spkr cable has very low inductance?

In theory... but in practice amplifier outputs and speakers can be lot more inductive.

 

Like with many many things.... as long as it's not "too much", then it's benign.

 

 

18 hours ago, andyr said:

Unfortunately low inductance carries with it the penalty of high capacitance - and whereas capacitance doesn't affect current ... it does have an affect on the amplifier driving the spkr cables!

 

It can do.... it depends on the amplifier as to "how much is too much".

 

Again.... as long as the capacitance is not too much, then it is basically benign.

 

[sir sanders zingmore]

1 hour ago, stereo coffee said:

The restriction of 20-20khz began largely self imposed by the digital era.

And what an improvement it was... Along with the development of speakers that can reproduce those signals. Back in the pre digital era we were lucky to reproduce anything above 14 or 15k. Happy days

[sir sanders zingmore]

1 hour ago, stereo coffee said:

A Denon 103 cartridge as example has specification here to 45Khz

Not bad for the time, but why limit ourselves? Pretty much any modern DAC will go higher with more accuracy

Edited March 1, 2021 by sir sanders zingmore

[davewantsmoore]

1 hour ago, stereo coffee said:

A Denon 103 cartridge as example has specification here to 45Khz

Have you seen the performance?!

 

 

Digital systems which store and replay above 20khz are trivial.....    but curiously, they don't "solve the problem".

 

The only relevance that frequencies above 20khz have on sound quality .... is as far as they relate to damaging (or not damaging) during the storage and playback processes, frequencies which are below 20khz.

[Monkeyboi]

1 hour ago, stereo coffee said:

The restriction of 20-20khz began largely self imposed by the digital era.  This was the price we paid for the sampling at 44.1khz and compliance with the Nyquist -Shannon theorem. Moreover it was the size of disc chosen, and time limitation of disc length before that,  which chose the 44.1khz sampling rate.  What we awkwardly also got,  was steep filtering at the Nyquist point, of just below half the sampling frequency.

 

One just has to read the on going dedication and interest to analog ( tape /phono ) to know something is missing in digital, never the less, I would be the first to agree it is very good at what it does. I think the most incredible moment in digital history was missed ( but could return )  in the form of moving away from PCM ,  instead to companded predictive delta modulation. We might then hear what digital was capable of, the DBX700 though was tied to VHS tape, and was its downfall, but the specifications were amazing.  http://www.technofileonline.com/texts/dbx700recorder86.html

 

Embracing that many pieces of source equipment other than digital has frequency response much higher, we can see trend to perhaps impose the 1983 digital era sound, by not thinking any higher.

 

A Denon 103 cartridge as example has specification here to 45Khz

 

 

This cartridge and some other models came about primarily due to the JVC CD-4 / RCA Quadradisc discrete 4 channel records which requires the cartridge to be able to reproduce frequencies to 45kHz and beyond.  The extended frequency response was normally only achieved by the use of stylii with special profiles like the Shibata and other makers using similar profiles.  Conical stylii are simply incapable of accurately reproducing the 45kHz signals as were many elliptical profiles in the mid 1970s, hence the development of the Shibata and compatible profiles.

 

I still have my Shure V15 type III cartridge fitted with genuine Shure VN35MR (Microridge profile) stylus and a NIB spare specifically for playing my CD-4 records in conjunction with one of my many CD-4 demodulators.  Before Shure released the Microridge profile I used their Hyper Elliptical stylii with very good results, but IMHO the VN35MR is significantly better with CD-4 pressings. 

 

Whilst analysis of the range of frequencies on some stereo vinyl recordings can reveal content above 20kHz it isn't as common as one would think.  

 

Cheers,

Alan R.

[rockeater]

4 hours ago, aussievintage said:

 and audibility of frequencies higher than 20kHz and cable effects on them, building strange cable structures that supposedly sound better etc etc.   This stuff just doesn't apply significantly down at low frequencies. The lack of understanding, is what allows people to theorise that it is having possible effects on audio,  and borrowing from the science lends some plausibility to those theories, until you actually examine it closely.

Very well said.

This very thing is very often used in marketing, for product differentiation in the market place.

Some new buzz-word is introduced and is backed by a very valid technical argument. Sadly this argument (circuit/feature/solution) very often has negligible - if any - impact on the actual sound reproduction.

I would risk saying that in analogue electronics, very little is done now what was not known 50+ years ago.

[davewantsmoore]

22 minutes ago, rockeater said:

I would risk saying that in analogue electronics, very little is done now what was not known 50+ years ago.

It's quite accurate.

 

We can achieve some things now which weren't practical 50 years ago ..... but it was all mostly "known" a long time back.

[stereo coffee]

On 01/03/2021 at 6:24 PM, davewantsmoore said:

It's quite accurate.

 

We can achieve some things now which weren't practical 50 years ago ..... but it was all mostly "known" a long time back.

Following on from this comment, there is always opportunity to explore parts connection that has been sometimes totally ignored. As example a LM336.   The 336 can also  be used as a series diode with unique properties. Can anyone having studied the data sheet see the possibilities. some will just see the manufacturers data supporting as a shunt device, but others may also see a totally unique alternative.  

https://www.ti.com/lit/ds/symlink/lm336-2.5-n.pdf