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Exploring laptop sound

Posted 16th April 2015 at 11:38 PM by fas42
Updated 27th April 2015 at 05:08 AM by fas42

As mentioned elsewhere, now have a laptop with reasonable internal sound, a HP Compaq 6830S (not a Pavillion, sorry!) of quite some vintage. My mainstay Dell over many years prior lost its sound many years ago, a USB port got cooked, and took down the sound circuitry at the same time; and what I was using as an interim, another Dell of nominally very good quality, had downright faulty sound, buzzed and rattled - was plain sick ...

OK, so the exercise here will be to see how good I can get the newly "installed" HP unit's sound to be, by my measures, using minimal or zero internal hardware tweaking - essentially working out what factors impact the sound, and whether the negatives can be circumvented. This gives an idea of how I go about things, what I use to "measure" with, what I'm listening for.

Trying a couple of CDs that I use often the signs were good - obviously no bass, and the volume is very restricted, but otherwise the sound was 'correct'...
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Old

Remote tweaking

Posted 25th March 2015 at 11:13 PM by fas42

A thought has popped into my head ... I enjoy the process - well, most of the time, :D! - of refining systems so that they deliver what I call convincing sound - a quality beyond what people typically achieve with audio systems assembled and "optimised" in conventional ways. And I've been able to help others at times move in the right directions, to advance what they're currently achieving.

So, I'm curious whether there are any out there, lurking :), interested in having a one to one interaction with me in having a go at getting something better out of their systems. Before wasting any more time on pursuing a silly idea, I would be curious if anybody is interested? And if you don't like to "expose" yourself to the great unwashed, :D, just send me a PM!

Cheers,
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Old

Doing interesting things with electronic keyboards

Posted 30th July 2014 at 01:44 AM by fas42
Updated 30th July 2014 at 11:24 PM by fas42

Provoked into Yet Another Project, fiddling with the Yamaha PSR-6700 Portatone we bought over 20 years ago, for my wife to have fun with. This is a solid unit, quite heavy, well thought of even now, with 76 keys - was top of the range, and was the best sounding of the brands and models we looked at the time, in that type of thing. Sometimes called an arranger keyboard, because it can do fancy backing accompaniments, the one-man band thing ... ;)

For those who are not into such, this is an all in one box, very sophisticated synthesizer with internal amp and speakers. Think of it like a reasonable hifi system, where the source material is computer generated, and can get as fancy and realistic as one wants, especially these days. Even in bygone decades remarkable music was created using such devices - Peter Gabriel's well thought of 4th album, Security, was based extremely heavily on sounds from the Fairlight CMI, an Australian made pioneer of this technology.

As...
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Old

A Better Audio Comparison Tool

Posted 2nd June 2014 at 07:25 AM by fas42
Updated 14th July 2014 at 02:01 AM by fas42

I've mentioned a few times the difficulty in using the software tool, DiffMaker - and others have experienced similar issues. So, I'm thinking seriously about attempting to put together a "better" utility, something that will be more intelligent in correlating between different versions of sampled waveforms, wherever they came from. And it will be specifically aimed at trying to ferret out the deep down differences, not the obvious stuff like frequency response, phase shifts and the like - but rather the low level, detail variations that seem to be so important in subjective quality evaluation.

To give an idea of the "challenge", consider taking 2 recordings from 2 vinyl plays of a particular record. Having already seen what results, this is impossible for the likes of DiffMaker to handle - the constant speed variation between the 2 captures completely defeats it. But this what I would aim to be able to deal with, to synchronise in meaningful ways between...
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Old

How good can the sound get?

Posted 12th April 2014 at 02:40 AM by fas42

This will be a collection of ideas developed and experiences encountered in my personal foray into the world of audio. In part, this is to counter much of the negativity and beliefs out there about the limitations of bog-standard, [I]vin ordinaire[/I], reproduced sound from conventional recordings, heard via a normal pair of speakers.

First of all, the sound can get very, very, [I]very[/I] good. Far beyond normal hifi, better than "live" much of the time ... so how can that be so? Because, typically for the recording session the positioning of the microphones, and acoustics, are optimised and tweaked by the sound engineers to pick up a "quality" well beyond what you as an ordinary audience member, concert goer, would experience.

So, how good? Well, for a start you can get "invisible" speakers, meaning that they can't be perceived as being the source of the sound; even if you go up to them and stare at them very closely, and move...
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Old

2,000W into 1 ohm

Posted 12th February 2014 at 05:10 AM by fas42
Updated 13th December 2014 at 12:52 AM by fas42

I mentioned in a thread a while ago about doing an exercise of engineering an amp capable of delivering 2k watts into a 1 ohm load, with distortion aiming at the magical ppm figure. This is still happening, and making progress ... key problem as I saw it was managing crossover distortion intelligently - I'm looking at a conventional class AB output stage at the moment - and it didn't make sense to try and control it using a classic global negative feedback approach.

By nature I'm an excellent scavenger, I look to see what ideas are already out there - so I'm trying out some concepts in using local negative feedback. This is evolving, step by step - and showing promise: in a simulation of the output stage only, getting effectively 2kW in 1R, at 200kHz with reasonable stability - and the waveform at this stressful frequency looks pretty good, there is still some crossover glitching, but I'm reducing the visible level of it steadily.

.
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Old

Fix it time for PC monitor speakers

Posted 16th December 2013 at 06:23 AM by fas42
Updated 22nd June 2014 at 06:35 AM by fas42

Bummer!! After mentioning that Brad's (bcarso) units were doing very nicely I swapped CDs while they were set to max. volume, doing a good job on a classical piece. Unfortunately, the new disk was heavily compressed pop, my mind was elsewhere, and I hit the volume control a second too late - everything's OK except the right speaker has dropped about 6dB in volume, :( ...

I suspect that some protection circuitry has tripped, but it's not resetting. Which means, unless anyone has a good idea otherwise, that I'll have to dive inside and sort things out. But, on the other side of the equation that may be an excellent thing to do, it will give me a chance to do some more adventuresome tweaking ...

Trouble is, I'm lazy ... :D
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To boldly go where no audiophile, or, perhaps just me, has gone before ...

Posted 23rd December 2012 at 04:07 AM by fas42
Updated 23rd December 2012 at 04:11 AM by fas42

As 'threatened' in a comment in abraxalito's blog I'm going to kick off posting and linking to some samples of sound generated by myself, at the moment examples of replay on my system, recorded using a very basic technique.

I'll probably regret it, but I'm going to put up a rough and ready trial run, to give a smell of what I'm aiming at. It's full of problems, but it gives some good indicators of what I'm dealing with, and hopefully some feedback will help me for future runs.

The system is my 'dud' HT all-in-one setup, heavily tweaked, and the recording device is a Fujifilm S4000 camera, which does HD video rather nicely, with mono 44.1/16 audio thrown in - that's handy. To maximise sound quality and minimise card storage used, hopefully, the lens was covered while recording, yes, no pics! Unfortunately, signal to noise is poor and the automatic volume control keeps falling over its feet, but you can't get everything for that sort of money :) ...

...
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Old

Sydney HiFi show - a mostly eye opening, not ear opening, exercise ...

Posted 22nd October 2012 at 09:58 PM by fas42
Updated 23rd October 2012 at 11:33 PM by fas42

Well, as mentioned elsewhere checked out the first proper show we've had in decades, and in hindsight it has been a very worthwhile, educational experience. Not because I heard magic audio I've never heard before, but, because I then browsed a collection of other people's thoughts and takes on the various sounds heard at the event, on another, Australian, audio forum.

Which showed me that people are in very different spaces, as regards to what is considered, "proper sound". Obvious of course, but it still throws one, makes one question one's ideas and thinking on matters ... for a split second, at least ... :)

My personal take on the show is that there has been a very discernable improvement in the standard, or average, quality of sound of a normally assembled system which has had only a minimal amount of tweaking applied to optimise it. Problems that were obvious in previous such efforts were far less apparent, you didn't want to run screaming from...
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Audio heaven? No, not me, the other guy ...

Posted 12th July 2012 at 01:39 AM by fas42
Updated 16th July 2012 at 12:16 AM by fas42

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...
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