Here's an interesting article where Warren East is commenting on ARM's competition with Intel. But for the sting in the tail, scroll down to the comments. The first one appears to be from an Intel insider - fascinating stuff. Let's hope it doesn't get pulled

ARM, TSMC lead Intel in SoC, says CEO East

He (nc3) says :

Intel's 22nm also has much higher leakage, cost, worse analog, worse RF, worse high V transistors in terms of specs and the type of devices offered.

This article is a fascinating peep behind the curtain of the current economics of semiconductor production through the eyes of a major IP player - Nvidia. More evidence that Moore's Law is grinding to a screeching halt I suggest.

Nvidia deeply unhappy with TSMC, claims 20nm essentially worthless | ExtremeTech

While doing some research on making an ultra low distortion analyzer I stopped to look at the Fluke 510A that has been siting on my shelf for years. Lots more on the 510a here: https://assets.fluke.com/manuals/510A_AD_imeng0000.pdf

In short a low distortion (.005% or better) 10V +/- .002% reference oscillator. There are very good numbers and by 1970 standards exceptional.

I was looking at it because I was researching AGC circuit for oscillators. This is an interesting implementation with its standards lab precision accuracy and stability. However its not simple and the critical parts are expensive (an ultra stable voltage reference, ultra stable resistors etc.)

In any case I was wondering if the distortion can be reduced still further. At the time it was built .002% was about as good as possible in practice and better would be hard to verify.

In short, after a number of experiments I got the distortion down to .0003% THD (30 KHz...

This follows a suggestion from another member -- thanks, bear! -- to chronicle at least one journey in optimising sound. And, yes, it's not one of my efforts, because the way I do things is very messy: they look incredibly messy, full of false turnings and bits of "I wonder if this is actually doing anything positive now". Enough to get anyone watching closely thoroughly confused ...!!

The story is that a small music listening group kicked off, then faded away. But from that an ongoing exercise began, where a younger, very enthusiastic DIYer was happy to hear my feedback on what path to take with his system, and this has continued for a couple of years, with quite substantial, positive gains in sound quality, to this day.

So, to give a clearer picture of the angle I'm coming from I'll attempt, from memory, to list the steps taken, in fairly general terms, and what the various ups and downs in the process were ...

At the start, when I first...

If I ever have my DCX break and need another XO, these tools look like they make miniDSP a real choice.

the Active Crossover Designer web page

I alluded to this in the first post on the thread, and it's worthwhile "defining" it a bit more.

Everybody would have a gut understanding as to what I mean, but what actually is it, and how do I measure it, to assess whether I've achieved it? There are the people who live and die by the conventional audio measurement yardsticks, and then there are the others who feel that these animals leave a lot to be desired. Again, look at the activity on the "Sound Quality Vs. Measurements" thread ...

Well, I'm pretty obviously in the latter camp, the standard numbers that an AP setup will pop up will mean very little, and since my project includes speakers the nightmare of getting meaningful distortion figures for the full path of the sound exists. So, I'll use the next best thing, my ears.

To make life easy here, I'll use a pretty accessible test object: the acoustic piano. We have one of those beasts in the listening area, my wife plays,...

By tnargs:

[QUOTE]I was assuming we were going to take something like a Behringer 2031A (2 way, 8", active, affordable) and see what tweaks are on the table.[/QUOTE]Most perceptive ...

[QUOTE]Whenever I see a measured FR of a Behringer it looks nice and smooth and flat, off axis too, so it seems a decent start.[/QUOTE]Exactly so.

[QUOTE]Although Lynno's post is true enough, I thought we would be keeping the drivers and looking at any gains from astute use of felt or resin (on or around the cone/dome), replacement of dust cap, stiffening or dampening the pressed steel driver frame... what else?[/QUOTE]Possibly will improve the frame in some such fashion; and look at stronger coupling of the whole driver assembly to the carcase such that vibration is transferred in the most direct path to the surface the monitor is sitting on.

But these things will be only addressed after the electronics are sorted out, and I see how well the driver...

I always seem to end up optimizing my headphone amplifier circuits for higher impedance headphones, this mostly happens because I own a pair of 300 ohm HD-600s and it is tedious to design for both the voltage requirements of high impedance headphones and the current requirements of low impedance headphones.

Not impossible, just, for the class-A designs I seem to be building recently, increasingly large, heavy, and impractical.

Complimentary transistor circuits, however, offer the opportunity to swap voltage for current at something close to the same design cost. They are therefore a practical topology for efficient class-A power delivery into low impedance headphones. As a design experiment, my aim is to discover how far I can leverage an ultra-low-voltage, unity gain circuit for compactness without sacrificing sound quality.

Ok. Back-of-the-envelope calculations:

A typical 16 ohm in-ear-headphone has a sensitivity of 100-105...

...