if you say so...
very poor excuse. I'm not even asking for names, what I'm asking is a proof for lack of correlation with standard measurements.
when all else fails, throw in the maturity thing. it's the ace of spades of logical fallacies, it always works
call it what you want, I'm not looking for approval. your or anyone else's opinion is irrelevant as long as it's not backed up by facts. this is diyaudio, not a social gathering.he doesn't own anyone anything. that is obvious. what he does is promote the myth that there are demons hiding in the standard measurements. this is what I'm doing: http://www.diyaudio.com/forums/loun...vips-commercial-affiliations.html#post3402888
the emphasis is mine and note that it's another user who said it.
theorize? what? where? did he try it and I missed it?
facts are required the moment you start posting stuff which is not backed up in any other way except "it is well known that", "everyone knows it except you" etc. it is "logical fallacies 101".
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Maybe a car analogy would be a class D amp is like a Nissan GT-R, very easy to drive fast as it is computerized and takes care of balancing everything. But feels sterile. On a track, it can keep up with many supercars but lacks soul and looks kind of industrial and ugly. A nice handbuilt class A is like a nice older Ferrari that takes a lot more skill to drive fast on a track, may have strange behaviors, costs a lot more, but has soul and people love them and wish they could have one. Just the sound from the Ferrari's exhaust note is unmistakable. I use and like my class D's but I confess that I would also love to have a nice hand built boutique class A room-heater and would not turn it away if someone gave it to me.
I believe a more appropriate analogy would be class a amps are the coal burning trains back from the '50s and class d amps are aeroplanes running on kerosene.
This parallelism matches better the feeling of "computerized" and "soul".
I prefer travelling by plane even for the shortest distances.
Not only scientific measures but good vocal recording as well. At least semi- anechoic. Surprised? Ha-Ha.
suntechnik: did I say it wasnt useful? I only object to your statement of it being the ONLY useful tool, which is farcical. I believe its very useful, but not exclusively useful
Mr PP, Yawn, not interested in your blow by blow, you are convinced you have all the knowledge clearly and further research is either pointless or needs the answer first before it is uttered.
I could answer and you would simply bounce it all back again with your trademark nit-picking
meanwhile 2 fairly accomplished engineers who have made real innovations in the area from both the speaker and the box; seem quite interested in the same line of inquiry. while you continue poking holes with only the power of your mind and keyboard...
you are like an intellectual wet-blanket
Mr PP, Yawn, not interested in your blow by blow, you are convinced you have all the knowledge clearly and further research is either pointless or needs the answer first before it is uttered.
I could answer and you would simply bounce it all back again with your trademark nit-picking
meanwhile 2 fairly accomplished engineers who have made real innovations in the area from both the speaker and the box; seem quite interested in the same line of inquiry. while you continue poking holes with only the power of your mind and keyboard...
you are like an intellectual wet-blanket
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I appreciate Class D discussion a lot. Yet not quit sure if opposite piston diesel engine like Subaru Boxers are purchasable in USA or not.
Back to stereo. Class A superior than Class D in terms of primary objective function. Period. Pure maths.
"Stories" (or lets make it straightforward just bloody commercial) like "ones switches from HiEnd Class A to Class D and Class D sounds superior" are subject for anechoic chamber measures.
P.S. I really enjoy PWM for light switches. I am running Schneider Electric ones. Cool stuff! Handles chandelier up to 350W while being tiny to be installed into standard wall mounting and dissipates almost nothing. I mean COOL!
Do you actually comprehend the science and mathematics behind class a&d? (retorical question of course).
Actual question: Do you have at hand measurements that two amps one a and one d with the same effort in built quality and same quality of components perform in a way that proves a is superior? Please convince me.
goes both ways.
your interest is not a requirement
remember, this is not election campaign or high school popularity contest.no. you are convinced that I am convinced of that.
further research is not pointless and obviously AP2 has something going for him. the distortions seen in those graphs are indeed indicative of audible problems. what I'm aiming at is the idea that such distortions are hidden in the standard measurements.
yes, I would and I see nothing wrong with it. the problem arises from the fact that your happen to hold opposing views and react accordingly.
where is the part where I claimed that class D is the end all be all? boy, don't I wish!
I was not aware of the fact that a Nobel prize is required to contest that 1+1=3.
everyone is entitled to an opinion.
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one of the things I've been planning to build is a simulated loudspeaker load.
I would be interesting to see some real-word measurements with a real load driven by real music, wish I had a good acquisition board
strange as it may seem at fist look, I think AP2's measurements are useful and give a real indication of actual problems. what is missing is more measurements in order to understand when and why it happens. the fact that it happens with one mysterious amplifier doesn't say much.anyway, anyone wanna give away a high end data acquisition system?
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they are hidden by standard measurements, because standard measurements do not include a real reactive load, so they arent hidden, they are simply not there. all covered in the posts youve been quoting, but seem to somehow misunderstand. THAT is why I couldnt be bothered, you seem to have as much problem understanding English as AP2 has writing it.
instead of trying to understand the essence of what is being said and often it seems DESPITE understanding it, you pick holes in the delivery. i've seen it a number of times, feigning interest but the only interest seems to be in the argument surrounding it, rather than the contribution to, or indeed purchase of the designs under discussion.
instead of trying to understand the essence of what is being said and often it seems DESPITE understanding it, you pick holes in the delivery. i've seen it a number of times, feigning interest but the only interest seems to be in the argument surrounding it, rather than the contribution to, or indeed purchase of the designs under discussion.
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that is one aspect.
but AP2's measurements are not with a real load (I think) and yet indicate a problem.
I think the load issue is only part of the problem and is not even what AP2's getting at.
one other problem I see is that linear amps don't seem to inherently fix the issue.
again, you're entitled to your opinions. the only ones having a word to say about it are the mods.
these days I tend to only buy equipment after auditioning it in my room and with a return policy.
it's funny that you don't want to accept that even I agree that at least some class D amps have some shortcomings and I'm very interested to understand why. the explanations so far don't hold water for me but I have high hopes, I think the future lies with them.
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A simulated loudspeaker load is not the same as a real loudspeaker load.
yes, back EMF but it's closer than a resistor.
I used to make measurements with a real loudspeaker (my loudspeaker) and real music (one advantage being that I don't have to use new loudspeakers every test), at large listening levels. the only conclusion was that I need a good data acquisition board in order to draw even the grossest conclusion
maybe a petition to Audio Precision or Prism to add time-domain measurements would help?
one other thing. I own and use a class D amp. it has none of the problems Kal and the OP describe, quite the contrary. instead, compared to all the linear amps I've A/B'd it against, it has somehow veiled and recessed highs. I'll be A/B'ing the following days/weeks against another decent class A/B one. I'm almost sure it is the same amp AP2 measured
last time I brought up class D in a discussion it was about the Devialet D-Premier. the audience asked "class what?" and showed no interest
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in the good tradition of being interested in the argument only...I thought we would all be riding around in personal spaceships by now.
Maybe an electric car some day will perform better than a Porsche. I guess it is fun to speculate into the future - but we live and play our music only in the present moment.
one of the advantages of the electrical engine is that is has a very different torque vs rpm curve. moreover, you can control the torque. not possible with a combustion engine: at rpm X you get torque Y, period. so in a way electric cars are already outperforming Porsches. the real problem is that the good ones are expensive and filling a gas tank is more convenient compared to charging batteries. and a Porsche is a Porsche, a Tesla will never be a Porsche
plus, I would think no one buys supercars to hear no exhaust note.sometimes car analogies are just as seductive as incorrect
in the good tradition of being interested in the argument only...
one of the advantages of the electrical engine is that is has a very different torque vs rpm curve. moreover, you can control the torque. not possible with a combustion engine: at rpm X you get torque Y, period. so in a way electric cars are already outperforming Porsches. the real problem is that the good ones are expensive and filling a gas tank is more convenient compared to charging batteries. and a Porsche is a Porsche, a Tesla will never be a Porsche
sometimes car analogies are just as seductive as incorrect
Regarding Tesla vs torque...AFAIK DC engines are better at low RPMs than Tesla's ACs. Michael Faraday invented DC electric motor.
it's possible, I haven't worked with DC motors except when I was a kid and found joy in watching things spin.
I worked with 3-phase AC engines in the automotive field. the guy who developed the control blocks was too busy to give me a comprehensive education on it and, like always, getting the thing to work is rather more important for the employer than understanding it... but, one thing I know is that it was capable of full torque at 0 rpm. and it should, because it needed to turn the wheels of a largish SUV when stationary. with no switchable gears available
Should I? I might see it quit as opposite. You guys, like from Philips marketing department ones, has to convinced us, consumers, that Class D is superior not only for your profits but it is somewhat better for us, consumers, as well besides just been ECO-friendly. That is what marketing department is getting payed for actually right?
BTW I cannot see any issues with that since most consumers has not idea what frequency domain is about or why absence of FIR makes LPs sounds better than Philip's RedBooks. Or like mercury filled CFLs are well know to be ECO-friendly nowadays.
he only conclusion was that I need a good data acquisition board in order to draw even the grossest conclusion
What are your requirements for a good data acquisition system? Nice DAQ's are not very expensive nowadays. What bit-depth and sampling speeds do you need and how many channels?
Certainly, if all you need is 96 kHz at 24 bits depth and two channels (XLR input), you can get a number of nice digital audio recorders for around $270.
For example:
H4n Handy Recorder
It seems that two channels should be sufficient for monitoring input vs output. At 96 kHz and 24-bits you should be fine with sampling speed to resolve the artifacts you are describing.
If you want something more engineering-like, a $400 vibration analysis DAQ might be in order:
USB DAQ Devices with 8 Simultaneous Analog Inputs - Measurement Computing
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