If one has a genuinely inquiring mind, then the process should be as follows: someone does something really 'dumb' and claims it makes a, positive, difference ... then, it either makes a difference - any explanation put forward by that person as to why, is irrelevant- or it doesn't. So, the truly curious will repeat, mimic, replicate the procedure as best he can to determine for himself whether there is any merit in it - and proceed from there.
The really dumb thing to do is to decide, upfront, that it can't possibly have any impact in a positive sense, for any reason whatsoever - and just discard it ...
The really dumb thing to do is to decide, upfront, that it can't possibly have any impact in a positive sense, for any reason whatsoever - and just discard it ...
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The other really dumb thing is to take the statement, and believe every word, and then purchase whatever the device that may have had an impact.
If one has a truly inquiring mind, one would base any experimentation on known laws of physics and a sound understanding of the physiological process of hearing.
One would recognise that one's inquiring mind, represented by the mind's perception of sensation, is not a valid measurement tool for incremental change in any field let alone sound, and so any testing and claims based solely on the observations of the involved parties should be treated as barely more credible than Brothers Grimm are as a reference material for anthropology in medieval Europe....
One would therefore use a good defensible and statistically based method to identify if the "positive difference" actually exists.
Good luck with that approach. How much time have you got? Smart people filter stuff out.
Ahhh, time - the old enemy! Yes, the number of things that one can experiment with rapidly spirals out of control - so my solution is to work backwards: I know what level of sound quality I'm chasing, the goal is quite nicely defined, as an experience that has been repeated many times. So, all I need to do is try enough techniques and ideas that others have played with, until I get the result I'm after.
Since what I'm pursuing is a highly subjective hearing response, the measurement approach is not very useful, not at the moment at least. I go by the language used of the parties who have tried something, read between the lines - that determines, for me, whether it may be worth investigating ...
The audio game is still far too sloppy, to be able to use precise approaches. I come from the computing world, where incredible levels of sloppiness are part and parcel of how the industry has involved - yet, amazingly enough, things are done just well enough that systems, applications work, most of the time,. I always was curious about whether one could 'prove' that a computer program was 'correct' - but this is still one for the "too hard" basket - sufficiently good enough is about as good as it gets ...
Since what I'm pursuing is a highly subjective hearing response, the measurement approach is not very useful, not at the moment at least. I go by the language used of the parties who have tried something, read between the lines - that determines, for me, whether it may be worth investigating ...
The audio game is still far too sloppy, to be able to use precise approaches. I come from the computing world, where incredible levels of sloppiness are part and parcel of how the industry has involved - yet, amazingly enough, things are done just well enough that systems, applications work, most of the time,
. I always was curious about whether one could 'prove' that a computer program was 'correct' - but this is still one for the "too hard" basket - sufficiently good enough is about as good as it gets ...
Yes, I was referring to TH only, still need to adapt to this SMD world
I did buy an IR oven from the Chinese friends, used it a few times, not very successfully.
It's hard for me to evenly manually scrape on the SMT paste using a mask; either get paste under it or too little on the pad....
Jan
I had telephone designs that used SMT wave soldering. The boards had through hole components (ICs, switches and electrolytics) on the component side and SMT resistors and chip capacitors on the solder side.
This was before ROHS and the solder wave was cooler than required these days
Hi,
Regardless of positive or negative, all materials can possibly have an impact on the reproduction of sound.
Ciao,
so are we saying solder resist can affect the sound
Not at audio frequencies, the coating is approx. 15 microns, on a double sided board, you have 1.6mm below the trace of pretty much the same dielectric. Now I say double sided PCB because if it was a multilayer then you would have stripline structures, traces buried on inner layers covered top and bottom with this evil stuff (epoxy).
So what we have to do is firstly:
Work out how signals travel.
Work out the effect dielectrics and especially Er has on the wave travelling.
Get yourself some simulation software that because of the frequencies you have to work up to (high speed digital/analogue/RF) has a provision for adding solder resist to the board stack up, then run the simulations...at audio frequencies.
We have to consider layer stack up and materials for high speed cutting edge designs but for audio stuff, and most normal designs no effect.
So instead of sprouting meaningless comments regarding these things investigate what is going on, realise there are a million more things that do have an affect and move on, then we can concentrate on the important things in the reproduction chain. Instead of well one o two people fantasised that they can hear a difference between PCBs with solder resist and PCBs without.
Printed Circuit Design & Fab Magazine Online
Selective soldering is the standard way to do the few through hole components that are on most boards these days.
Stencil design and solder paste deposition is a well studied and documented procedure, as 60% of SMT reflow faults can be ascribed to bad solder paste screen printing.
There is some good stuff on this site, but you have to log on to get to the downloads, I have had them do numerous presentations for production staff working on SMD lines regarding the solder paste screening process and associated problems.
SMT Stencils - Applications | Tecan
Stencil design and solder paste deposition is a well studied and documented procedure, as 60% of SMT reflow faults can be ascribed to bad solder paste screen printing.
There is some good stuff on this site, but you have to log on to get to the downloads, I have had them do numerous presentations for production staff working on SMD lines regarding the solder paste screening process and associated problems.
SMT Stencils - Applications | Tecan
I guess someone with such an enquiring mind will never assume that things fall downwards, or that the Sun tends to rise in the east, or that arsenic is often poisonous, or putting his b**ls in a vice will be painful. He never assumes anything, but always trusts what people tell him and tries it for himself. He thinks the Darwin Award is a high honour and is puzzled why it is always given posthumously.fas42 said:
Hello Frank.Hi,
Regardless of positive or negative, all materials can possibly have an impact on the reproduction of sound.
Ciao,
Yes, in my experience, many materials most certainly do effect audio signals.
The fun is in the mixing and matching
.Dan.
The fun is when one has a board with SMDs on both sides and TH parts. Special carriers are used which have openings in the bottom only in the areas where the TH component solder pads are exposed to the solder wave.
Up until about 10 years ago we had a plant 8 miles south of here that did our prototype builds. It was a custom manufacturing business which was sold.
We then had to hand assemble double sided SMT boards with TH parts for Prototypes. Our manual Pick-and-Place station and the reflow oven were removed about two years ago and we were told all builds will be done in one of our manufacturing sits.
We were hand assembling boards as it took months to schedule a build in production. Turn time with productino is now down to the point where they can provide boards almost as quickly as we could have assembled them, and they have fewer errors.
Up until about 10 years ago we had a plant 8 miles south of here that did our prototype builds. It was a custom manufacturing business which was sold.
We then had to hand assemble double sided SMT boards with TH parts for Prototypes. Our manual Pick-and-Place station and the reflow oven were removed about two years ago and we were told all builds will be done in one of our manufacturing sits.
We were hand assembling boards as it took months to schedule a build in production. Turn time with productino is now down to the point where they can provide boards almost as quickly as we could have assembled them, and they have fewer errors.
I've used these mainly more versatile in some ways, as you don't have to have a protective screen made, so great for short runs:
Selective Soldering | Products | An ERSA soldering machine, soldering station or BGA rework system - best solutions for PCB manufacturing industries
Now more and more UK production is farmed out and in house facilities either go completely or cut back to almost useless...
Selective Soldering | Products | An ERSA soldering machine, soldering station or BGA rework system - best solutions for PCB manufacturing industries
Now more and more UK production is farmed out and in house facilities either go completely or cut back to almost useless...
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