I just attend a local "Hearing Session", to compare some commercial power amps. Some of the people there claims theirself to be "Audiophile"(but with no electronic understanding)
I found an interesting thing. Some amp have what they say "3D sound reproduction". The singer is sitting in front, while the music is in far background, it can be heared with closed eyes. The drums are in far left, the piano.... etc, just like reading a map.
With another amp, the whole sound (singer+music) just at the same place, in a wall just right infront of me. No "depth" in music.
All the people there loves the amp with that 3D Depth sound reproduction. They say the more expensive an amp, this effect is more obvious (is this true?)
We are not talking about digital delay thing here, just plain analog amp compared with analog power amp. No time delay, no fancy processor.
What makes an analog audio amp can make a good "depth"? Is there a trick in the designing process?
I found an interesting thing. Some amp have what they say "3D sound reproduction". The singer is sitting in front, while the music is in far background, it can be heared with closed eyes. The drums are in far left, the piano.... etc, just like reading a map.
With another amp, the whole sound (singer+music) just at the same place, in a wall just right infront of me. No "depth" in music.
All the people there loves the amp with that 3D Depth sound reproduction. They say the more expensive an amp, this effect is more obvious (is this true?)
We are not talking about digital delay thing here, just plain analog amp compared with analog power amp. No time delay, no fancy processor.
What makes an analog audio amp can make a good "depth"? Is there a trick in the designing process?
i sell the stuff for a living, so the most non-technical way to explain it is this...
a cd is recorded in stereo, or at least mixed in that way. if it is live, or mixed in a studio environment, there is depth and a 3d recording. certiain things are farther away than others, and some things are more left than others.
so simply, if the reproduction is accurate, these sublteties should come through with the playback as well. some speakers are very good at doing this. in my opinion, it has to do most with the speakers, then the amp, then the source, then the preamp.
but the amp and speakers have a huge role in this.
ive had several cds where the recording is such that certain notes actually come from behind you. there are a couple of DVD-audios where this happens in 2-channel. this is just a phasing thing. with my system, i can hear things on the side of me, and sometimes (rarely) behind me. it is not uncommon to hear things further out than the speakers, or behind, or in front of them.
a cd is recorded in stereo, or at least mixed in that way. if it is live, or mixed in a studio environment, there is depth and a 3d recording. certiain things are farther away than others, and some things are more left than others.
so simply, if the reproduction is accurate, these sublteties should come through with the playback as well. some speakers are very good at doing this. in my opinion, it has to do most with the speakers, then the amp, then the source, then the preamp.
but the amp and speakers have a huge role in this.
ive had several cds where the recording is such that certain notes actually come from behind you. there are a couple of DVD-audios where this happens in 2-channel. this is just a phasing thing. with my system, i can hear things on the side of me, and sometimes (rarely) behind me. it is not uncommon to hear things further out than the speakers, or behind, or in front of them.
cowanrg said:
I think 95% of that effect is lost due to room acoustic issues, 4.9% is lost due to lousdspeaker issues and 0.1% is lost due to electronic issues, assuming there is a suitable recording as a starting point. Studio-mixed recordings are not likely to contain that kind of information
The 44.1Khz PCM format itself also forces some information loss since phase differences between channels are quantized in 22.7uS increments [sampling period] while analog recording can store almost infinite phase differences between channels. Anyway, 44.1Khz PCM stores enough information to make the effects clearly perceptible
It's not so hard to create such recordings, just place two identycal mics with its sensing elements about 20cm away one from the other and record each into a channel. Move sound sources around the mics and then listen to the results with matched speakers preferably outdoors or in a very dead room, or also with headpones
Even cheap electronics tends to have enough channel matching and separation to not alter that phase-difference information, but selling electronics is much easier than selling loudspeakers or room treatments. Actually I only enjoy to listen music outdoors, rooms are very very frustrating, particularly smaller ones
Most 'audioplhiles' know nothing about acoustics and blame electronic equipment when his wife moves a carpet or something in the listening room and 'something changes in the sound'. Sound waves interact with every single object or surface in the room before reaching our ears and these interactions are somewhat 1,000 times stronger than the ones caused by electronics...
The room is the same, the speaker is the same, the position is the same, the AC line is the same, the CD is the same, the cables are the same, the crowd is the same, everything is the same.
Just change the amp, then other amp, then other amp.
Why one amp has more "Depth" than the other? How to make this?
Just change the amp, then other amp, then other amp.
Why one amp has more "Depth" than the other? How to make this?
lumanauw said:
I know exactly to which you refer. I experience it while testing and evaluating various different tube amplifiers while testing them on my new speaker designs. I think it has to do with the way the phase of the signal spectrum gets distorted within the amplifier circuit between input and output. One term that describes such an instrumental (electronic) effect is differential phase where the propagation time of the signal through the amplifier is different at different frequencies dependant on signal amplitude at the moment in time. The presence of negative feedback or not can effect this as well. The output transformer and any interstage transformers can also effect this. The trick is to get it 'right' when building an amp design. Many try, far less succeed. I think having the shortest signal path i.e. the least amount of stages to corrupt the signal is part of the path to such desired 'transparency' in the sound. Well regulated and suitably bypassed power supplies to each of the active gain stages are also part of the way to better sound.
Interestingly, the '3D' effect is sometimes more obvious in amps with relatively high crosstalk between channels. The effect has been exploited in several psychoacoustic processors, but I haven't yet come across an explanation for it.
Certainly, one of the best defined soundstages I've heard came from an ancient Armstrong amp with audible crosstalk, and I once had a startling experience of realism (in this respect) from an ultra-cheap Amstrad music centre which I was repairing for a friend.
Certainly, one of the best defined soundstages I've heard came from an ancient Armstrong amp with audible crosstalk, and I once had a startling experience of realism (in this respect) from an ultra-cheap Amstrad music centre which I was repairing for a friend.
Eva said:
This is not completely true, even with this quantisation you can have
much more exact phasing due to antialiasing. I used this effect in
my 3d-soundroutines, where i had the problem that i had to use
accurate phaseshifting with 22khz output. With hires interpolation
between samples (phaseaccurate) you completely knock out this
problem. This antialiasing happens automatically when converting
from analog to digital. The phaseshifting is very subtile, but the brain
uses this information to locate the sound in a 180degree-circle.
Given an eardistance of 20cm, a sound 10meters away, rotated 90deg
you get a phaseshift of 1.16ms, going to zero if the sound is exact
in front of you (or behind)
Elevation of the sound and detecting if its front/back, does the ear
by checking reflections and filtering inside the ear, even the reflection
from shoulder is important.
Mike
"3D" is just another subtle description of so called "sound stage".
A tend to back up behind UE's words.
Also many loudspeakers can't reproduce a "soundstage" very well, and there are even super expensive loudspeakers which don't even have a linear frequencies/time -domain reproduction which is even a much worse problem than for amplifiers.
Cheers
A tend to back up behind UE's words.
Also many loudspeakers can't reproduce a "soundstage" very well, and there are even super expensive loudspeakers which don't even have a linear frequencies/time -domain reproduction which is even a much worse problem than for amplifiers.
Cheers
There is another term that I hear only from so called "Audiophile / Golden Ears". Never heard the term here.
They said they can hear if the sound is "Standing Still/Stable/Not Moving"----> that is good, and the sound is "Shaking slightly to left and right/Not standing steady/Not standing Stable"----> that is bad.
Strange way to hear an amp, eh?
I'm afraid that this is all hoax, since I'm sure none of this is measurable. Even some people cannot hear it (I can hear the 3D effect, but cannot hear this "Standing Still" sound like)
I wonder how we can make an audio amp with good "depth"
They said they can hear if the sound is "Standing Still/Stable/Not Moving"----> that is good, and the sound is "Shaking slightly to left and right/Not standing steady/Not standing Stable"----> that is bad.
Strange way to hear an amp, eh? I'm afraid that this is all hoax, since I'm sure none of this is measurable. Even some people cannot hear it (I can hear the 3D effect, but cannot hear this "Standing Still" sound like)
I wonder how we can make an audio amp with good "depth"
Hi, Rcavictim (what kind of accident you have with RCA?)
"Different frequencies travels at different speed at power amp" or
"There is a frequency dependant local resonance(s) that makes one frequenci(es) more obvious than other frequenci(es)"?
2 opinion with 180deg properties.
Agreed
Should I translate this to
"Different frequencies travels at different speed at power amp" or
"There is a frequency dependant local resonance(s) that makes one frequenci(es) more obvious than other frequenci(es)"?
Suggestion no.1
Suggestion no.2
2 opinion with 180deg properties.
There may well be an awful lot of placebo effect floating around audio circles, but it is certainly possible for an unchanging sound to appear to move around. Perhaps the easiest example to test is if a sound is located precisely equidistant between your ears, it is quite hard to tell if it is in front or behind you (if you can't see the source). Sometimes it may even seem to flip spontaneously between in front and behind.lumanauw said:There is another term that I hear only from so called "Audiophile / Golden Ears". Never heard the term here.
They said they can hear if the sound is "Standing Still/Stable/Not Moving"----> that is good, and the sound is "Shaking slightly to left and right/Not standing steady/Not standing Stable"----> that is bad.
I'm afraid that this is all hoax, since I'm sure none of this is measurable. Even some people cannot hear it (I can hear the 3D effect, but cannot hear this "Standing Still" sound like)
I wonder how we can make an audio amp with good "depth"
It is quite measurable, most effectively with the human ear. Psychoacoustics is wierd, but desirable knowledge to help untangle the phsychology from the technology of hi-fi.
Anyway, I agree that the loudspeaker and the room it interacts with totally swamps any contributions from the amp or preceeding stages.
Mr Evil said:
I disagree strongly with this shortsighted notion. Sure the loudspeaker and the room it is in has most of the control over the sound, but once you set those in place I have found it easy to hear tonal characteristic differences in different tube amplifiers, and between tube amps and sand amps. I have been with untrained ears who have also reported hearing the same preferences and differences as I. It may be that a certain factor threshold of speaker quality must be reached before such subtle but clearly discernible differences become apparent between amplifiers. I don't waste my time listening to many different amplifiers in a successive evaluative test session on low quality speakers.
lumanauw said:
lumanlauw
Answer to first question: There are two possible answers to this question, you pick the one that best suits you.
a) I was in a home once of a consumer of a modern RCA color TV when it stopped working and the only practical option ended up being to put the TV in landfill and purchase another new black plastic piece of crap. I was deeply disturbed and traumatised by this event.
b) I thought rcavictim was a damned clever phrase parody to the well known trademark RCA Victor and since I actually like and collect the vintage TV's that were made when (the real) RCA used that trademark, and real wood for cabinets, decided to use it as a moniker.
Answer to second question:
Differential Phase = single note, goes through amp faster or slower depending on how loud it is.
A certain mono sound whose frequency content varies with time, played both from L and R channels may appear to move horizontally if the transfer function of the room causes some frequencies from the left channel to arrive to the ear sooner or later than the same frequencies from the right channel
When the sound uses some frequencies it's perceived in one place and with the sound uses other frequencies the perceived location changes. This causes frustrating listening experiences, specially when the room has +10dB to -20dB modes around bass notes and up to 15ms of ear arrival time error and the bass comes from randon locations or ever disappears depending on the note. Just typical-home room-acoustics
This is a very usual phenomena found in rooms that ruins any horizontal spatial information present in the recording. It may be also aggravated by too high tolerances in loudspeaker crossover network components or by driver mismatching with age, voice coil heating, ambient hummidity, asymetric loudspeaker placement, etc...
Amplifiers and other electronic gear is not likely to cause any harm as long as it causes the same gain and phase displacement to both channels
If one amplifier 'A' reproduces spatial information properly and other amplifier 'B' appears to place everything in the center with the same setup, then B amplifier has been deliberately cheated to work in mono!!
With nowadays' aggresive marketing policies that kind of cheating is likely to happen
When the sound uses some frequencies it's perceived in one place and with the sound uses other frequencies the perceived location changes. This causes frustrating listening experiences, specially when the room has +10dB to -20dB modes around bass notes and up to 15ms of ear arrival time error and the bass comes from randon locations or ever disappears depending on the note. Just typical-home room-acoustics
This is a very usual phenomena found in rooms that ruins any horizontal spatial information present in the recording. It may be also aggravated by too high tolerances in loudspeaker crossover network components or by driver mismatching with age, voice coil heating, ambient hummidity, asymetric loudspeaker placement, etc...
Amplifiers and other electronic gear is not likely to cause any harm as long as it causes the same gain and phase displacement to both channels
If one amplifier 'A' reproduces spatial information properly and other amplifier 'B' appears to place everything in the center with the same setup, then B amplifier has been deliberately cheated to work in mono!!
With nowadays' aggresive marketing policies that kind of cheating is likely to happen
It is, however, exploited by fairly high end gear, such as the Frankenstein (sp) processor, which was very well reviewed.
Let's not forget that, with the possible exception of binaural recordings reprodced through headphones, the two-channel soundfield is 'fake' anyway - Blumlein's genius compromise over a whole wall of mics / speakers for stereo reproduction.
In the case of the cheap Amstrad, it was breathtaking - I could hear the entire hall ambience, and precisely pinpoint small noises made by the audience 'behind me'. Unfortunately, I've been unable to reproduce such an astonishingly 'real' effect since - I'd be very happy if I could!
Eva said:
Yes, just have look at these P.M.P.O. ratings of 150Watts ! Reads great,
but if you have a closer look, it has 5watt rms....
What was P.M.P.O. ? PureMarketingPowerOutput ?
And why not selling a mono amp as stereo, just with one of the 2
outputs reverted ? Sounds like hell of ultrawide stereo !
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