How do TINY speakers produce such BIG sound?

[VWWall]

Dis someone mention horn? "Dig" these (scroll down)

http://www.royaldevice.com/custom.htm

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.

 

[VWWall]

An extra point:
If you can try that flanger experiment, set the amplitude on each channel
the same.
What's amazing about this, is the delay part of the panned signal can place
the location further left without level difference than the level
difference can do without the delay, even when the level is full in one
channel and ABSENT in the other!

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.

 

[kony]

What system, i am curious, electrostatic, dynamic, dynamic wit ha coild in teh membrane?
Or piezzo?
I once build a smal ldynamic one.... when you find you need permanent magnet bias...
Also did some experimenting with piezzo.

Is yours betetr what you can buy commercially? (mine was not).

no i meant headamp. I usually listen to Sennheisers or
Grados.

 

[Jan Panteltje]

no i meant headamp. I usually listen to Sennheisers or
Grados.

OK, I had a Senheiser too.
Was very good.

 

[Lostgallifreyan]

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.

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'.

 

[kony]

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.

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.

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'.

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.

 

[VWWall]

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.

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!

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 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.

 

[Lostgallifreyan]

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.

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.

 

[Lostgallifreyan]

Perhaps we need to concentrate more on the message and less on the
medium.

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.

 

[Boris Mohar]

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.

That guys approach to amplifier design is questionable.

 

[CBFalconer]

.... 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.

--
"If you want to post a followup via groups.google.com, don't use
the broken "Reply" link at the bottom of the article. Click on
"show options" at the top of the article, then click on the
"Reply" at the bottom of the article headers." - Keith Thompson
More details at: <http://cfaj.freeshell.org/google/>
Also see <http://www.safalra.com/special/googlegroupsreply/>

 

[VWWall]

Boris Mohar wrote:
... snip ...

You snipped wrongly. This was VWWall input:

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.

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.

 

[kony]

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.

 

[Lostgallifreyan]

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.

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.

 

[kony]

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.

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.

Btw, saying that critical listeners all accept 2-channel stereo is probably
a bigger generalisation than any I have made.

"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.

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.

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.

 

[Lostgallifreyan]

Artifically trying to reinterpret what the original was,
only reduces the SNR further.

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.

 

[Lostgallifreyan]

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.

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."

 

[Alex Coleman]

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.

Is Hyperprism 'Harmonic Exciter" available for Windows?

http://www.arboretum.com/ seems to refer only to Mac OS X.

 

[Jan Panteltje]

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.

This is not correct.
For a modern single chip version 75W rms woofer driver I use:
http://panteltje.com/panteltje/amplifier/index.html

Nothing extraordinary,. very simple, drives the woofer (L+R combined)
from the PC speaker, or if 5 ch the bass.
I have mounted the speaker to the floor..... cone down...
That extra floor vibration adds to the tiny PC speakers....

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.

 

[Lostgallifreyan]

Is Hyperprism 'Harmonic Exciter" available for Windows?

http://www.arboretum.com/ seems to refer only to Mac OS X.

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).

http://www.arboretum.com/products/plugins/hyp_main.html

Link for Windows package there. For the most part I found the Sonic Foundry
effects far better, for GUI, accuracy, bug-free handling, but HExciter.dll
is indispensible, I never found anything better than that.

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).