That's really carrying things to an extreme! The one I built did use two four by eight foot sheets of 3/4 inch plywood, but no concrete! :-)
I noticed the power amp uses transformers. At one time the "hi-fi purests" claimed iron core devices distorted the waveforms. Transformer less designs were all the rage, neglecting the fact that the signal had probably been through many transformers before it reached the final listener.
Virg Wall, P.E.
My MSI motherboard has a Realtec AC97 six channel sound system. There is a built in demo which uses delay plus volume to "move" a sound source. Now that everything has gone digital it's much easier to implement this sort of thing. I can recall experimenting with screen door springs with phono pick-ups attached, to simulate audio delay.
Made some interesting sounds, but hardly hi-fi!
Virg Wall, P.E.
no i meant headamp. I usually listen to Sennheisers or Grados.
On a sunny day (Fri, 12 May 2006 15:07:55 -0400) it happened kony wrote in :
OK, I had a Senheiser too. Was very good.
VWWall wrote in news:7b39g.1573$ snipped-for-privacy@newsread2.news.pas.earthlink.net:
Nor is 2-channel stereo. But it's a convention we've come to accept.
Actually, many sounds are processed with delay panning to set a realistic position. WHile it's possible to overdo it, rendering the effect weird for all but the largest ears and heads, there's nothing wrong with doing it in moderation, it just means that those with largest ears and heads will hear it slightly narrower field than most.
The one thing that gets to me about the purist thing is that I've seen people worry about silver speaker cables, or the tiniest differences in an MP3 encoding process, and various other things, when the differences in the musicl process, or the final mix, or even a bit of EQ on the stereo mix, all make far more bold changes to the sound. If it sounds good, people will accept is hi-fi, so long as they don't see that crude assembly of signals at their end.
If you want a great take on that whole thing, listen to a song by Micheal Flanders and Donald Swann. >:) It's called 'A Song Of Reproduction'. It encourages a healthy wariness of too much narrow refinement. The reason why such things as big sounds out of tiny speakers are amazing people right now is that it's taken the computer industry to shift people's perceptions far enough and fast enough to make it possible to try things which have actually been commercially and technically possible for decades. It's the limited concept of what is 'hi-fi' that has had to break down first.
People can agrue till death about how hi-fi is simple, only to reproduce the original sound, but it can't. No two-channel system can. Which is the point, The only way out of a circular argument is to accept new ideas into 'hi-fi'.
The answer is easy, the goal is not "bold changes", it's accurate reproduction. Some will psychologically err when they assume their further tweaking of audio cables sounds better without an ABX test but even that isn't valid- because multiple changes below a threshold of discrimination (taken alone) can sum to a perceivable difference.
Audio is so subjective though, it's fairly impossible to generalize that "people will accept is hi-fi" when talking about all the possible variations. Even a crude $3 AM radio sounds pretty good compared to silence but set it next to something better... so ignorance can be bliss, the road to perfect sound is long and winding.
Those who do the most critical listening seem to disagree and prefer 2 good channels over digitally mutilated sound. There's nothing wrong with digital at all, to preserve, not change the sound.
A "musical" instrument or human throat, (non -linear), produces acoustic air pressure variations, which are shaped by the environment, (recording studio or auditorium). These are partially sampled by a non-linear microphone, and converted to an electrical signal which is then amplified millions of times by an almost linear device. This electrical signal is applied to another non-linear device, (speaker), where a second acoustic air pressure variation is created. This is modified by the environment, (listening room or auditorium), and partially sampled by the most non-linear device of all, the human ear.
After all this, the nerve "signals" from the ear are interrupted by the device about which we know the least, the human brain.
Without the latter there would not be tens of "audio magazines", hundreds of audio device manufacturers, and the makers of "monster cables" and gold plated connectors would go out of business!
The best any system can do is to "please" the brain. Since pleasure is highly subjective, no two people will hear exactly the same thing.
Perhaps we need to concentrate more on the message and less on the medium.
Virg Wall, P.E.
kony wrote in news: snipped-for-privacy@4ax.com:
Go outside to hear some birds or a plane flying. Then take a pair of the finest small-diaphragm condensor mics and record same, experimenting as much as you like with mic placement. Listen to the result through the best audiophile gear you can reach. Then try to figure out where the surrounding depth, or actual spatial height went. Finally, figure out which experience has 'fidelity'. And no, you won't need ABX testing to tell you.
Btw, saying that critical listeners all accept 2-channel stereo is probably a bigger generalisation than any I have made. In fact, even if you stick rigorously to the way a spatial field is set up in purist 2-channel stereo, the logical outcome for 'fidelity' is actually to listen within a spherical volume, itself set within an equilateral tetrahedral volume defined by four speakers, one above the centre of an equilateral triangle. You'd have to spend a lot more money to do that though, even than was spent by the guy who made a brick subwoofer. :)
VWWall wrote in news:ji79g.3662$ snipped-for-privacy@newsread1.news.pas.earthlink.net:
Agreed. That's what I'm getting at. Purist forms try to work like a scientific 'control'. That only works to show you about the reality if you also experience the rest of it. When people channel it through a purist reproduction system, they only hear the interpretation of an interpretation, etc, which is that chain of audio you were describing. To get more of tha actual experience, we need to try other ways to channel the information to us. That is what 'fidelity' really means. There was a time when stereo hi-fi was revolutionary. That appears to be long gone, now turned into a refinement of craft, and no more. We will not get closer to the message, the raw source of the event being recorded, unless we either go there, or find new ways to bring it to us.
That guys approach to amplifier design is questionable.
... snip ...
It's not the existance of the transformer, it's the transfer characteristics, frequency range, clipping, etc. No transformer works down to DC. All will clip at some level. The heart of the Williamson amplifier was its output transformer, which was wound to exacting specifications, with specified core material. Even then, it was strictly power limited to a pair of 6L6s or the equivalent. I think 2A3s were actually used, because of their better transfer curves. Transistors made DC coupling feasible.
You snipped wrongly. This was VWWall input:
Speakers do react, (badly), to DC, hence the DC coupled amp had a big capacitor in series with the speaker.
I was just pointing out one of the foibles of the "hi-fi clan". One of the best amps I ever built used a pair of WE 300B tubes with a transformer of course. I see these tubes are now selling for $400 each. ($900 matched pair.) I'd better check the garage--I think I still have a pair! :-)
VWWall, P.E.
It depends on subjective definition of hi-fi. I don't dismiss tube fans but they are looking to color the sound with distortion. If they like that, great, they found what they want... but high fidelity it is not, IMO.
kony wrote in news: snipped-for-privacy@4ax.com:
I agree there. It's a very nice sound though, and it does work for some music that comes from times when this was the only way you could do it. The history is short, on the scale of music making, and the accepted sound has a lot to do with context. I'm old enough to know valve sound and young enough to know PWM based systems as an equally formative effect on what I think is the ideal. While PWM is still new enough to be mainly considered for raw efficiency, not hi-fi, it's like the development of op-amps, getting closer all the time. To me those things will become hi-fi, reducing the gain stage to a clean magnifying window, as magical and also as prosaic as an achromatic lens. The idea of using valve preamps, or even digital emulations such as the technique used in Sound Forge's 'Acoustic Mirror' will seem like a nightmare to some, but many others will use it. That way you might play music from the 60's or 50's not only through a valve sound, but even the valve sound of equipment of the time it was made. If people can model components with spice modelling, and use sample rates up to 192 KHz with bit depths of 24 or more, as is happening now, the resolution will be finer than we can perceive, and the majority of people will be calling it hi-fi. If it brings them more ways to match a sound with the conditions that created it, I won't be telling them they're wrong.
yes, the recording and subsequent playback is not accurate. However, what is preserved is as close as can be achieved. Artifically trying to reinterpret what the original was, only reduces the SNR further. Noise is not just that picked up in a circuit, not just from bad design but now also artificially introduced, deliberately.
"Accept" means that it beats the other alternatives of artificial generation of spacialization. If there were more than 2 tracks recorded, certainly that would be more realistic, but without the addt'l channel information present, trying to make it up with forethought can only lower the true SNR.
Nonsense. Fidelity always means reproducing what is present in the recording. Not pretending to know what is missing and readding it. If the recording is not satisfactory to your sense of reality, it needs to be recorded differently, not played back differently than each channel reproduced accurately. Of course that can include speaker positioning, but it never includes digitally manipulating the signal to some artificial state.
kony wrote in news: snipped-for-privacy@4ax.com:
Actually that point is only true if you're trying to recover something that is already gone beyond recovery. :) Consider the harmonic regeneration possible with things like the Hyperprism 'Harmonic Exciter'. Technically that thing makes distortion, thus has NO place in hi-fi.
That might be the end of it, but it isn't. I sometimes restore sound from FM recordings and vinyl. I'll use FFT NR to reduce the steady background noise by 18 dB or more, and this can also reduce the highest frequencies of the sound I want to keep. When I use the Hyperprism tool I use it very minimally, to rebuild some harmonics on the top of the surviving frequency range. This spreads the background noise back up the spectrum too, but more thinly than in the original, by far. Sure, I've absolutle butchered the signal if you want to compare it with the original, but the original was a faded copy of something irrecoverable, and the restored copy has a clarity in the upper harmonics that is very good, carries the fine detail to make it easy to hears words in low-level voices, and to easly tell the tibral character of instruments apart, and to hear the original reverb properly again.
Sure, I've reduced the SNR if you consider the exact waveshape and original spectrum, but if the FFT NR and the harmonic regeneration are set up well, the message, the real meaning for the signal, is enhanced. I've played the results of this work to people who are very strict about the use of ABX in testing, and who are very particular about their listening gear, and not one has said I damaged the sound. Some have been very enthusastic about how clean it sounds. I used to make bad mistakes in overdoing the treatment, but I've found that it works, and the better I get it, the more likely it is that one method works in more cases with little modification.
If you limit the notion of SNR to a purely technical expression of changes to an original record, it's technically impossible to 'improve' it anyway, so to me, that is a bad basis for the definition. My method has more risks but I think it can also get real improvement.
kony wrote in news: snipped-for-privacy@4ax.com:
All of science is filled with assumptions and compromise. That's what modelling reality is all about. I agree that the conditions of the recording are what matters most, but where those cannot be recovered, what else are you going to do? Again,. if you reduce the concept of signal and noise to a purely mechanical basis, you are left with nothing but trying to fight decay, there is no more creation of any kind. There is a difference between creation to regenerate the clarity that is wanted in an old recording that has lost it, and the creation that takes big liberties for their own sake, but the difficulty of making the decisions is no reason to suggest that trying to do so is invalid.
As someone said on a forum recently, "Those who say that something cannot be done should not interupt with those who are doing it."
Is Hyperprism 'Harmonic Exciter" available for Windows?
On a sunny day (Sat, 13 May 2006 05:20:49 GMT) it happened VWWall wrote in :
This is not correct. For a modern single chip version 75W rms woofer driver I use:
As to you original remark, thsre do exist DC couple transistor amps with output cap (and usually a boost cap to lift the driver voltage), but only for low power stuff.
This chip I am using is a CMOS chip, and very very stable (note the missing R+C across the output.
It is a very nice chip.
Alex Coleman wrote in news:Xns97C26794BE72771F3M4@127.0.0.1:
Yes. I haven't kept up with latest versions, so I don't even know how far they got, but the one I use is v1.55b I think. It's a 'DirectShow' plugin, and if you can get the actual file you won't need the whole install, just put the file where you want then register with Regsvr32.exe (which is as easy as dragging icon for HExciter.dll onto that for Regsvr32.exe).
If you want to experiment with the use as I described it, some starting parameter settings would be these: Harmonic Type Odd+Even Quality Level Best Harmonics % 24 Dynamics % 0 Crossover Hz 3600 Spectral Mix dB 0
That's a very minimal effect, pretty safe to use on anything, but maybe too subtle in recordings with badly worn HF signal. I used this one for BBC radio relays from live Proms concerts. The next thing I try if I want more obvious effect is raising 'Harmonics %' to 32 and lowering the crossover to
3200 Hz, then listening carefully to any sounds like sustained piano or soprano voices as those will be the first to show up audible distortions. (Note that this might just be enhancing existing distortions that we otherwise wouldn't notice).PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.