nawww, there's *loads* and *loads* of 100W Marshals. I world say, probably a million of them.
Yep. Not many of them. 200W is pretty rare.
Yes. You can get units that do this, like BBE exciters.
There is a tube sound, as in guitar amps *unclipped*, and it is measures easily as a tube sound, like in the 1% range. However, I agree that
*hi-fi* tube amps of good quality, all things being equal, all sound the same as trany amps.
There is also more to the simulation then just clipping distortion, e.g. the output impedance of a tube amp can be several ohms. Speakers vary over the frequency range of say, 6 to 200 for a nominal 8 ohm. Indeed, when a tube amp clips, it generats x-over distortion. Have a look at the waveform on a scope some time. The coupling caps start charging when the grid starts taking current.
You have to compare apples with apples. Guitar amps are *not*, hi-fi amps, so they do have a sound.
Kevin Aylward snipped-for-privacy@anasoft.co.uk
formatting link
SuperSpice, a very affordable Mixed-Mode Windows Simulator with Schematic Capture, Waveform Display, FFT's and Filter Design.
I've added deliberate distortion to low end before kit to make it sound better. Frexample modulating the sound with mains ripple really warms the bass up, and is how old valve radios sound warm despite their crappy bass response. Just put some hum on any pin that achieves this multiplying, but does not add it. Adding gives hum, multiplying gives warm bass without hum.
does it? AIUI phono gives less dynamic range, not more, than CD. And more crosstalk, giving less stereo depth.
sounds more
huh?
huh?
of
this is gettin silly.
when you
...when you realise that you made them up in order to shoot them down, while claiming theyre someone else's claims. Its called a straw man.
It doesnt tell us a whole lot about the sounds of valves vs trs.
let
have a
I'd like to do that, and see what happens. Unfortunately I have neither the equipment nor the time these days. I've grown up.
in
it was you that wrote the silly stories.
If you had offerd a convincing argument for there being no detectable difference between how valves and trs sound, I'd say you had a conclusion well worth considering, but you've offerd not a single jot of evidence for such here.
Unfortunately, I don't think a double blind test is nearly that easy. What I mean by this is that the CD will be superior to the LP in ways that are *easily identifiable* to the listener. The most obvious of this is the low level pops and clicks of the LP, which are entirely absent from a CD. So "double blind" under your description is *not* double blind -- the listener can easily identify the source with pops and clicks and maybe even rumble, as the LP source. Thus listener bias could not be eliminated with this sort of "straight double blind test."
The test must be designed to prevent this. In absolute terms, I don't think it is possible. The CD will always be identifiable compared to an LP with _otherwise identical hardware and music program material_.
What I believe may be of more interest, and more practical, is to test all those golden eared hi-fi audiophiles for identifying "graininess" or whatever they claim the demerits of standard 16-bit CD audio are *in comparison* the to claimed merits of LP's.
I would propose *adding* phono type pops, clicks, wow-flutter, and rumble to a CD recording at the same S/(N + otherBadStuff) ratio that would be present on an LP. (It could be done by recording the playback of a blank LP and summing it to the music source.) Thus it would not be obvious to the listener which source was the CD or LP during testing, thereby eliminating that source of bias. One could even take the actual LP, play it, and record it to CD. If the listeners could consistantly ID the sources, then there may be some truth to the complaints about CD's. If the sources can't be ID'ed, then the comparative performance question between LP and CD can be dispensed with forever.
This test could not "prove" anything other than the _comparative_ level of performance. That is, it does not prove that audiphile listeners can't hear quantization ("graininess") of the 16-bit audio signals when LP style degradations are not present in the medium. It could only show that LP's S/(N + otherBadStuff) ratio is sufficiently bad (good) to swamp (highlight) the CD formats shortcomings.
If the LP's "N + otherBadStuff" swamps the CD's "N + otherBadStuff", then it would be logically difficult to justify the LP over CD.
This more limited falsification test is more practical as it compensates for bias.
I think Ban was suggesting that the CD be recorded from the vinyl, and would therefor have those defects as well.
Ban wrote: "Unfortunatly or rather fortunately all these arguments loose ground when you compare a record player with a recorded CD from the same player.: ^^^^^^^^^^^
The point is that the CD has duplicated these defect "perfectly" (enough for the ear), thus CDs are not inferior to vinyl.
Why not just record the vinyl, as Ban has suggested? If the golden-ear can't distinguish the difference then CDs are better than vinyl, since they add nothing to the "experience".
If you move LP noise onto CD to disguise the source for an AB test, that will work fine if the surface noise has no impact on overall sound quality, but I would very much expect that it has. Just as you can sometimes improve perceived sound quality by introducing distortion by modulating it at 50Hz, so you can change and sometimes even improve the listening experience by adding noise.
If only it were as simple as cleanest is best, but it doesnt seem to be.
So that leaves you to test a whole multitude of things, including CD with and without added snap crackle and pop, vinyl in A1 condition with no crackle and so on. No doubt the ABCDEFGHIJ tester will simply be confused!
I've been following this thread mainly out of curiosity.
I own both the cassette tape (remember those?) and CD version of "The Divine Bette Midler." To _MY_ ears, the cassette version has more depth and "space" (for lack of a better term) than the CD version, at least _on the equipment I have_.
When I purchase a CD, I rip the songs onto my hard drive as MP3s. By utilizing features of my sound card (SoundBlaster PCI512) I _ADD_ about
30% each of chorus and reverb to the audio. The resulting music sounds better _to my ears_ than the plain (or "pure") audio.
My point is, everyone's ears are _different_. What sounds best to me may sound so-so to someone else.
And so the battle rages on...
RoyalHeart
--
A thoughtful pause, then resumes the prince, "We must Learn from
Yesterday, Live for Today, and look Forward to Tomorrow, for The Past be
The Present, and No Less The Future."
That "it does" have an impact was exactly his point. So is your point that CD's "sound better" if LP noise is added? If so, I smell a market for "noised up" CD's, since it would be cheaper to make CD's noisy (with LP noise), than to mess with LP's themselves. How about a knob on the amp, right beside the bass control that says "LP noise?"
Are you claiming that one can "improve perceived sound quality" by creating distortion, and then modulating that distortion with 50 Hz" Please explain, because it sounds strange. I have never heard of such an "enhancement" technique in hi-fi systems.
Why would that be so?
"Cleanest is best" is pretty much the definition of hi-fi. So if you want to add distortion, you need to explain why you think it helps. Are you saying you don't like the mix/production of the source material and distortion will make ot better? That's fine if you do, but that is not the definition of hi-fi, which seeks to minimize coloration by definition. That is, it tracks the source with *high fidelity*.
I suppose an LP without these impairments is exceedingly rare, if it exists at all. This is the common reason of why the tester will be confused. That is exactly the point and why it is suggested as a test.
If your argument is for a lab instrumentation grade LP and player that only white-coated lab rats in a clean room see, then you can afford the same hedge to the CD: give it 24 bits and a 200 k sampling rate.
As far as hi-fi goes, the claims are typically made by the toob aficionados, not the other way around. So it is up to them to rationally explain (and provide evidence for) the claim. Ban is simply reciting common claims -- he didn't pull them out of thin air.
For creating music and particularly for electric guitar, the amp is part of the instrument, so any hi-fi arguments are void there.
If you seek to add distortion to your *reproduction* system via toob distortion, then that's your business. Doing so simply means you think the original production needed more distortion. That's okay, but it is by definition departing from the meaning of "hi-fi."
I adjust graphic equalizers sometimes because I don't like the tone balance of the original source. But that is, a linear operation (as far as not creating new frequency products), not a non-linear one like adding distortion.
I have here some recordings by a group called Sphongle, where kind of phono style crackling noises have been added deliberately in a few passages. These immediately sound much more "spacy" than clean parts. Can it have to do with the capacity of our hearing system to locate cracks very fast and precise? Imagine, that it once was a criterion to survive, when you could avoid being attacked by wild animals or Native American warriors. The wide frequency range of a "crackle" will give us easyly to identify and process clues about the environment, just as a blind man snaps his fingers or tongue to get usable echoes for visualisation. And the "space" feeling comes from the room response during playback, not from echoes recorded on the disk, as you can see with overdamped rooms which sound unnaturally dry and lifeless.
A particulary stupid way of argumentation is mocking, Mr.cat. Maybe your capacity to understand is low, but we said we wanted to compare the phono record to a home made CD of that same record played from the same rig. There are only these two feeds, which I bet you will not be able to consistently tell apart.
Same as before, added noise can improve the listening experience giving it this "lifelike" touch, which phono-lovers always complain is missing in digital recordings.
A technique I used on lofi is to modulate the signal by 50Hz. This does not cause hum, as adding would, it causes a warmer sound with the impression of much more bass. It is an effective way to address a shortage of bass. This method was routinely used on old valve radios, I guess unintentionally.
who knows
to
Take a track and play with effects and types of distortion. Its not hard to find music that sounds better with effects added. Its also not hard to see that some distortion can give a diffrent feel to the music: eg 50Hz modulation, sot clipping etc all give a different character to it. Its also fairly familiar territory that adding one distortion can partuially make up for another distortion. Eg adding bass resonance can somewhat compensate for inadequate bass response.
On the hifi scale the defects are smaller in magnitude, but there is no reason to expect the same principles to not apply.
and
I daresay thats so in some cases
yes and no. High fidelity does not equal perfect fidelity IRL. With any given budget you have to make choices between which imperfections you prefer.
If it were really about minimising colouration, hfi amps wouldnt have bass and treble controls. Nearly all do, for good reason.
He caimed that I believed xyz, which was pulled out of the air, and perhaps underconsidered. His further post indicates his ego has not yet recovered from this mistake, and he wishes to take it out on me. Today I dont feel like letting him.
part
think
is
only if you think perfection is attainable, and desirable. In reality no kit is perfect, so one has to choose between one set of distortions and another. If that werent so, all hifi kit would be the same in terms of sound quality. But its not.
Okay, I get it: it is simply a logical conclusion.
You're simpy translating all frequencies by 50 Hz, and presumably adding this to the original signal in some proportion. What is the technical definition of "warm?" I don't have any idea what it means in a quantifiable sense.
I would approach this problem differently: I would use a speaker with improved bass response, or short of that, turn up the bass control.
If it wasn't intentional, then it's not a "method."
That is not hi-fi, and listener response may be, and probably is, random across many listeners. So I have no way to comment.
For me, this topic is not about subjective favorites of individuals within and across large populations.
Sure, you can make it sound profoundly different. But again, that is not the goal of a hi-fi amplifier.
Just to be clear, the goal in amplification is transparency. That is, push all classes of distortion, even "linear distortion" to levels not detectable by humans.
I am quite familiar with the concept of predistortion in the radio communications field. In that field, the predistortion processing is specifically implemented to _explicitly_ cancel (null) distortion products occurring *later* in the chain. This nulling is not what is done in audio work, and nor is the technique of predistortion necessary in audio work, since traditional methods of distortion control are sufficient. (I'm talking about Volterra-Wiener polynomial type distortion/modeling. The null parameters are acquired via behavioral modeling.)
What I'm saying is that in audio work, one non-linear distortion is not "making up for another distortion" in a way that has technical and quantifiable meaning. It is simply an added (not nulling) non-linear effect, and thus is not hi-fi, by definition. "Hi-fi" always seeks lower distortion (to at least the point of inaudibility), not adding it, unless the addition is in effect a nulling distortion (meaning lower total distortion).
Where are you adding this "bass resonance" into the system?
Principles may indeed apply in theory, but the question is whether the defects are audible to humans and are thus quantifiable. This is where those who claim superiority of tube hi-fi amplification over transistor amplification always fall short of scientific standards. At least I am not aware of any convincing studies confirming the claim. To be fair, the dearth of good studies in the past and the ubiquitous nature of non-scientific lingo permeating the field make me cease looking. I felt that if it was that hard to ascertain the differences, they must be so small as to be irrelevent for most situations and most listeners. If there have been breakthroughs in the past 10 years, I am not aware of them because I'm not really looking.
I think the difficulty with using an amplifier unit as a non-linear distortion adder/processor is that it is not very controllable. That is, a hi-fi amp is designed to *not* distort, not to distort. Different distortion levels will be highly dependent on the volume level -- that is, volume is not independent of distortion. I could not call this a good audio processing design by any engineering standards I am familiar with.
Of course. But let's not lose sight of the problem definition of hi-fi: lower distortion to inaudible levels.
As it goes in the hi-fi reproduction chain, electronic amplification is the easiest and therefore cheapest dragon to slay. I predict most of the important power amplifier work in the future (it is already well started) will have to do with getting power/energy/size/weight efficient designs up to the hi-fi standards and low cost of the more traditional approaches. That's my opinion, anyway.
At worst, tone controls produce "linear distortion." They do not add spectral energy not already present in the source, unlike the non-linear distortion generated by amplifiers. Moreover, tone adjustment may have little to do with the source material, but may be _directly_ *nulling* a deficiency in, for example, a speaker system, since quality speakers can represent a major fraction of hi-fi system cost. They may also be compensating for the listening room problems, and not the source. Again, this is an example of a nulling situation.
Yes, tone controls may be (and are, of course) used to explicitly alter the spectral balance of the _source_ depending upon listener preference. However, this is acknowledged as a specific processing task, not an amplification task. Audible non-linear distortion products are a no-no for a box that is said to be simply a spectral balance processor. Perhaps the same should be true for an amplifier: "just amplify."
The delineation of tonal processing (or any other processing) from amplification is logical. However, combining power amplification with non-linear distortion destroys this separation.
The complete separation of variables is possible for tonal processing; most importantly is the separation of tonal processing from volume (average power level), although some iteration will be necessary. This is not so for the power amplifier (or even preamp?) which also used as a distortion adder ("distortion processor"). Volume and distortion are not separable. That is not a good design.
In short, if someone wants to add distortion or alter the tone, then that's their choice and subjective valuation. I could not argue with that. But adding non-nulling non-linear distortion is plainly not hi-fi, by definition. Only in the case where an added distortion explicitly nulls another can an added distortion be said to be "hi-fi." The linear distortion of tone controls partially compensating (nulling) the response of deficient speakers can be said to be such a case, and so remains in the realm of hi-fi. _Masking_ (rather than nulling) one distortion by introduction of another is not hi-fi. Also, the claimed merits of masking non-linear distortions have remained in the realm of claim, not proven fact, as best I know. Of course, if someone wants to do it and pay their own money to do it, why would I care?
During some long conversations, I once said to a friend that he thought of his "hi-fi" tube amp as as much of a non-linear processor as he did an amp. He agreed. I then explained to him why the non-linear processing was not easily separable from other system parameters. He had to think about that. For all I know, he still is thinking about it.
Lets start by quoting you on this, since it really is the key point imho:
bear this in mind in all of the below.
That is an inevitable logical conclusion from the above I think.
I would suggest that is an unrealistic definition. Hifi buffs have not generally claimed that lowest paper distortion spec is what sounds best.
It is well known different types of distortion sound different, therefore it is elementary to conclude that the amp with the lowest THD is not guaranteed to be the one that sounds best.
is it? why?
by
does
adding
yup.
no idea if there even is one. Trying it and seeing soon answers the question in a practical way.
missing the point. In the real world many cut price systems are used, and it costs money to add bass boost, add speaker bass response, and add amp power capacity to be able to run it. Given that cut price systems are used, the logical thing to do with them is maximise their abilities. This can be done at apx no cost by injecting mains junk into the amp.
If
you
helps.
Its really not. The 50Hz modulation method gets fairly consistent responses from listeners. The contrast between 2nd and 3rd harmonic distortion might also be, though I cant be sure. I really see no reason to think its inconsistent.
music:
to
is,
not
Whether that goal is achieved is another question. Many will argue that its not. If its not, we are indeed comparing one set of distortions with another, in a world of not quite ideal amplifiers, and the one with the most euphonic set of distortions wins.
Right, but thats a different concept to the one I was talking about. I was talking about things like eg adding 50Hz modulation to partially make up for lack of bass, and suggesting the same concept of semi-compensation occurs with distortions present in much lower percentages, ie in hifi amps.
necessary
not
I think its well demonstrated.
it,
if that were true, one would simply look at the THD of amps, pick the lowest, and that would be it, youd get best sound. Real life doesnt work like that.
I bring up the subject of lo-fi a lot in this because with larger levels of distortion it is extremely easy to see the effects, and thus the concepts in action. It is easy to take a basic 0.5w amp, with inadequate bass, and add 50Hz modulation. It is easy to compare 3rd harmonic with 2nd when youre running at 2% distortion, not 0.002%. etc.
Lots of people are familiar with the 50Hz modulation trick, though most dont realise thats how its done.
In a lo-fi one would usally add it at the speaker, with underdamped mechanical resonance(s). In principle one can add these things anywhere.
is no
the
Certainly thats another valid question. Im not sure its one we can asnwer in this thread though.
transistor
am
fair,
ignorance and unscience permeate most fields. That only means its not worth looking in the places where one finds no science. It doesnt make a field invalid.
so
This is why I keep mentioning lo-fi. With lo-fi you can turn the distortion levels right up, and the results are immediate and obvious.
Different
that
familiar
this is really missing the point that no amp is in reality distortion free. Any good designer is handling distortion: no-one has yet found a way to the 0% amp.
hi-fi:
I would suggest changing your definition. That may have been good when the term was coined.
is
Amplifier distortion has not been brought down to 0% yet, the dragon has not been slayed. Easiest to make good maybe, but to eliminate all problems from, no.
efficient
traditional
me too. Also I think more amplifier classes will come along with better efficiency, cost, or other advantages. I worked on a design that shifted the heat diss away from the output trs, but unfortunately it did not in the end enable any less silicon to be used.
have
non-linear
have
*nulling* a
can
But in reality they do not correct such defects. A look at any commercial speaker's response curve shows it can not be corrected with a bass or treble control.
These controls will lessen the infidelity in some areas of the spectrum, while worsening it in others. IOW the control's frequency response does not match the speaker's.
not usually.
alter
products
Im sorry but theyre inevitable. Its thus meaningless to say theyre a no-no. Theyre an inevitable which must be handled.
maybe one day that will be reality.
with
processing;
This
as a
It is part of every amplifier design on the planet, good and bad alike. There is no 0% distortion stage.
It is normal in amp design, and is used to lower overall distortion, but not cancel it.
"hi-fi."
(nulling)
so
I think that describes graphic equalisers, not tone controls.
Lets start by quoting you on this, since it really is the key point imho:
bear this in mind in all of the below.
That is an inevitable logical conclusion from the above I think.
I would suggest that is an unrealistic definition. Hifi buffs have not generally claimed that lowest paper distortion spec is what sounds best.
It is well known different types of distortion sound different, therefore it is elementary to conclude that the amp with the lowest THD is not guaranteed to be the one that sounds best.
is it? why?
by
does
adding
yup.
no idea if there even is one. Trying it and seeing soon answers the question in a practical way.
missing the point. In the real world many cut price systems are used, and it costs money to add bass boost, add speaker bass response, and add amp power capacity to be able to run it. Given that cut price systems are used, the logical thing to do with them is maximise their abilities. This can be done at apx no cost by injecting mains junk into the amp.
If
you
helps.
Its really not. The 50Hz modulation method gets fairly consistent responses from listeners. The contrast between 2nd and 3rd harmonic distortion might also be, though I cant be sure. I really see no reason to think its inconsistent.
music:
to
is,
not
Whether that goal is achieved is another question. Many will argue that its not. If its not, we are indeed comparing one set of distortions with another, in a world of not quite ideal amplifiers, and the one with the most euphonic set of distortions wins.
Right, but thats a different concept to the one I was talking about. I was talking about things like eg adding 50Hz modulation to partially make up for lack of bass, and suggesting the same concept of semi-compensation occurs with distortions present in much lower percentages, ie in hifi amps.
necessary
not
I think its well demonstrated.
it,
if that were true, one would simply look at the THD of amps, pick the lowest, and that would be it, youd get best sound. Real life doesnt work like that.
I bring up the subject of lo-fi a lot in this because with larger levels of distortion it is extremely easy to see the effects, and thus the concepts in action. It is easy to take a basic 0.5w amp, with inadequate bass, and add 50Hz modulation. It is easy to compare 3rd harmonic with 2nd when youre running at 2% distortion, not 0.002%. etc.
Lots of people are familiar with the 50Hz modulation trick, though most dont realise thats how its done.
In a lo-fi one would usally add it at the speaker, with underdamped mechanical resonance(s). In principle one can add these things anywhere.
is no
the
Certainly thats another valid question. Im not sure its one we can asnwer in this thread though.
transistor
am
fair,
ignorance and unscience permeate most fields. That only means its not worth looking in the places where one finds no science. It doesnt make a field invalid.
so
This is why I keep mentioning lo-fi. With lo-fi you can turn the distortion levels right up, and the results are immediate and obvious.
Different
that
familiar
this is really missing the point that no amp is in reality distortion free. Any good designer is handling distortion: no-one has yet found a way to the 0% amp.
hi-fi:
I would suggest changing your definition. That may have been good when the term was coined.
is
Amplifier distortion has not been brought down to 0% yet, the dragon has not been slayed. Easiest to make good maybe, but to eliminate all problems from, no.
efficient
traditional
me too. Also I think more amplifier classes will come along with better efficiency, cost, or other advantages. I worked on a design that shifted the heat diss away from the output trs, but unfortunately it did not in the end enable any less silicon to be used.
have
non-linear
have
*nulling* a
can
But in reality they do not correct such defects. A look at any commercial speaker's response curve shows it can not be corrected with a bass or treble control.
These controls will lessen the infidelity in some areas of the spectrum, while worsening it in others. IOW the control's frequency response does not match the speaker's.
not usually.
alter
products
Im sorry but theyre inevitable. Its thus meaningless to say theyre a no-no. Theyre an inevitable which must be handled.
maybe one day that will be reality.
with
processing;
This
as a
It is part of every amplifier design on the planet, good and bad alike. There is no 0% distortion stage.
It is normal in amp design, and is used to lower overall distortion, but not cancel it.
"hi-fi."
(nulling)
so
I think that describes graphic equalisers, not tone controls.
I'd say a kickass experiment would be to take a very expensive TOOB amp, and excise everything but the filament supplies, and replace it with a decent SS amp, but don't let the subjects know that - just let them _see_ the toobz and oxygen-free gold wires and crap, take two identical sets of speakers, or maybe even an AB switch, and sit it alongside a little slapped-together tranny amp with the same power output and frequency response.
I'd almost bet dollars to donuts that they'll swear the "toob" amp "sounds better".
Yep, I agree with that too. Of course it leaves the question open of whether the distortions are audible. In systems where speakers contribute >1% distortion I'm more inclined to believe it is audible.
distortion.
not
It
games
frankly the point here is obvious. 0.2% of even harmonics generally sounds better than 0.1% of odd. Thus hifi does not simply mean choosing lowest distortion figure.
THD
have
It may be the dream, whether or not it is achieved in reality is another question.
no
Then you havent tried it. Its too obvious to those of us that have, to need a study to confirm it. If you dont know the difference between crossover, clipping and 2nd harmonic, then amp design is presumably not part of your thing.
LP
I dont recall what you snipped... not to worry
Hz
No I did not say that. That that is a way to achieve some warmth clearly does not mean that.
It is? Damn, thought it was rec.food for a minute. Seriously though, those old debating games tell us nothing.
It has been, make it sound as good as possible on x budget.
snip
yup
Lots of kit is of such budgetness as to have inadequate bass response, eg portable radios, answerphones, various other portables, and budget goods generally. Also there are space constrained items such as laptops, mobile phones etc, where again modulation can help.
not
I dont have a study to quote you, just x years of consistent individual listener say-sos.
listening
Might be lack of knowledge. This is a forum primarily for people who design these things, how many here are familiar with the tcehnique?
That brings in other considerations. Knobs cost money, and 50Hz modulation is most useful on low-end bottom kit. And deliberate distortions, while it is known they can improve some music, are frowned on in better kit. Plus its no longer needed when you've got good bass anyway.
reason
reason
Theres someone who hasnt tried it, and had feedback from others nearby. It would be like a study to see if cats look different to dogs.
is,
not
that
hi-fi
Curious. I have 2 power amps downstairs, and the difference is obvious. But the situation is muddier when youve got mutiple distortions present at once, as is the case with hifis.
know,
Indeed, it is not consistent, and the tests not problem free.
between
the
That merely begs the question of whether those distortions can be heard or not.
snip
it
follow the argument.
is not
Play with some amps. Try modulation.
seeks
adding it,
lower
the
thus
no, and not relevant to the point
higher
No I'm not saying that. Thats why those 'ifs' keep cropping up.
no-one said there was a linear relationship
no-one said there wasnt a threshold. We dont know. If there is one, whether what we hear IRL is above or below it is another question.
a
indeed, no-one said it did
most
No they dont, we do (mostly) but most people do not.
yes, but not significant. Any account of listeners will need to take into account those that are not s.e.d. regulars.
Its really not nulling, as resonance produces quite a different output to the proper response. Bass resonance is a standard deliberate addition to most speaker systems. There are significant departures from nulling:
The output of a resonant system continues after the excitation has gone,
The output magnitude/time response is unlike the input signal
The resonance is triggered by other frequencies as well as the f_res
And in the case of lower cost ssytems, the resonance also contains higher frequencies than f_res as a result of nonlinear cabinet resonance.
is no
the
Bingo.
I
make
I would suggest that 50Hz modulation is a low hanging fruit. Few engineers today pick that one.
And as far as resources, theyre fairly sizeable. A company that produces a record breaking lower distortion amp can make lots of marketing mileage from it.
cost
true, but that does not mean reducing apparent distortion isnt worth following.
Most of us, regardless of wealth, still own minimal cost amplifiers, eg in portable radios, answerphones etc
Ditto for minimum size apps eg laptops, mobile phones.
Improving result per dollar of low cost kit is still a valid goal of engineers: it is in fact a core part of what we do.
severe
or
hi-fi
able
Really? Lets look at the last 35 years of commercial hifi amps. They've come a long way. How? Result per dollar, features, reliability, and buyer appeal. Result per dollar includes lower levels of distortion for a given price. This continues to matter, as huge amounts of money are still involved in portable and budget devices of all sorts, as well as hifi. Improving return per buck is very valuable - and yes that includes improvments in distortion figures that have no effect on the listener, since tech specs are a real-world sales consideration as much as are blue leds.
If you dont think its relevant, I wonder how competitive a designer you are.
be
listeners.
obvious.
audibility.
No such assumption. I think ive said that.
distortion
a
Or that it isnt.
all
IF. Do you have some evidence that no-one can hear it? Do you have some evidence that it is a commercial non consideration, regardless of whether it can be heard? I'd bet my last buck on the belief that the first company that produces a 0% distortion amp will gain substantial business as a result. And some extra business if they never even sell it!
Uhuh. The problem is money, and its an obvious one. As to whether todays commercial kit distortions are audible, we really arent sure, so its an issue.
And even when we do know, and it turns out we cant tell, it will still be an issue at a sales level. As an example we know printing block diagrams on amp facias does nothing, but some buyers believed they were functional latest high tech, and were encouraged to buy. Odd but true.
that
Tell me something. Since we know todays systems are not perfect (one only need look at speaker specs to see that), and we know that one distortion can improve a sound with another type, how do you know whether the type of amp distortion does or does not partially compensate for real world speaker limitations? We really dont know, so either way is possible. Why does it matter? Primarily, business. There is plenty of money riding on it. The real world is like that, trivia can get way more money than they deserve sometimes.
alter
processing
products
How can distortion products that are present in every audio amp be a nono??
hobbyists and consumers
everyone in the business of supplying those customers
people doing business with the above market sector
than
Most of us are commercial designers. To those of us in the consumer sector, it matters alright. Whether its science or nonsense it still matters. Those of us who designed feedforward amps enabled our employers to make a song and dance about the fact, regardless of whether it held any advantage outside of sales. Do you remember /know about when hifi amps broke the 0.1% barrier in the 50s? Big hoo-ha over that, financial futures made and broken on that one. The same game can be repeated.
be
Its an option.
I have no way to prove to you that modulation makes tinny amps sound better, but I still believe it does, and will still act on that belief with good reason, even if its not been proven to you.
then
with
fact
both have been done, cancellation is not the sole technique
This is huge, I'd be surprised if I ever get the time for another round. Happy designing. :)
ElectronDepot 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.