what do you mean? there are ways. you can add whatever sound track to a video using VirtualDub, for instance, and then burn that as DVD video with Nero. first is freeware, second is available as 15 days trial. I'm sure there are a lot of free apps that do the same thing, just do a bit of googling.
how is coding relevant? there will be an analog signal at the output. a sine is a sine no matter the encoding.
if the coding on the DVD translates to a lower level, just turn the volume up.
if I'm allowed to speculate, this will always be a controversial topic because intuitively one is seduced to think that there's something "special", for lack of a better word, going on during dynamic passages and that specific something requires huge currents that would not show in "normal" conditions (i.e. steady-state sines, "undynamic" music etc). I think this is because intuitively one thinks that the energy provided by the amp is used to accelerate the cone (high acceleration -> high energy, hence high power (high current)). is it the ubiquitous car analogy rearing its ugly head?
"acceleration equals gas consumption so the same must be true for speakers". only difference is that cars tend to be a bit heavier and the internal combustion engine works in a different way compared to a speaker motor but the energy is actually required to create the electromagnetic field and compress/expand the spring formed by the spider and the surround. little of it is used to accelerate the cone.
or think of it this way: let's say that you want to keep the cone at a constant excursion of a few mm. of course that means DC and will burn any real woofer in seconds if not faster so don't do it
but if you're willing to sacrifice your $$$ woofers, be prepared to keep a hand close and press on the cone, you may find the force is pretty serious, especially for a heavy cone/high loss woofer (low sensitivity). and... is the required energy low? no way, you'll be using a lot of amp power (if the amp is DC coupled and can actually hold a cone still).if this is hard to believe, think of it this way. if the cone mass were a significant factor in the equation, what would happen when the wave reaches its peak, the cone needs to stop in a fraction of a millisecond and then abruptly start to move the opposite direction? momentum comes into play and the motor would be incapable of controlling the movement. this will manifest itself as cone overshoot -> the cone starts having a "free will" which is not in accordance to the music -> distortion -> bad sound (maybe euphonic? think low damping factor amps and speakers purposely designed to work with them, I think Merlin designer for one said in an interview that they'll be making such a speaker). but, hopefully, driver manufacturers know better and the electromotive force is high enough compared to cone inertia so that there's no such problem.
if you're still not convinced, you can do a test I did. connect a shunt in series with the amp output. ensure it's small, just use a piece of magnet wire and compute the resistance. then play some "demanding" music, movie soundtrack etc. and measure the voltage across it. you can use the mic input of your notebook, you won't believe how good they are nowadays, noise- and distortion-wise. mine has a -125 dB noise floor and more than decent distortion. with the added advantage of good sensitivity (it's a mic input after all). or use a decent external soundcard, I bet they're even better. look at the voltage waveform (which is a current waveform, because it's measured across a resistor). spoiler: you won't find anything spectacular. in fact, what you'll be able to see is pretty much what you can derive from the output waveform and the speaker impedance. you won't see sudden sharp pulses, tens or hundreds of amps tall, like some marketing figures would have you believe. is there anything that can still hide from this test?
maybe I don't have the facts straight, feel welcome to correct whatever necessary. but please refrain from ego-boosting one-liners because the purpose is to make readers understand
IMO the math behind all this is too dry for most people who actually have a life and don't make a living out of this stuff intuitive explanations are few and far between so things stay "occult". so, unless one has a knack for the math side of things, one will be even more confused after reading the theory. I really, really doubt many hobbyists actually read and understood Thiele-Small from cover to cover. I'm not patronizing anyone because I confess that I rarely have the patience to go through these dry papers which often leave me wondering if the people writing them actually spend any time listening to music and/or have any interest in quality reproduction. not making up excuses, just uttering the sensation that too often these papers are done for the sake of the math and any interest in correlation with auditory perception seems non existent. one guy recently told me "if I know that an amp has 0.0001% THD, I tend to fool myself into thinking that it actually sounds better".excuse me for the rant, I tend to be rant-prone
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Pano's test relies on the FACT that a digital signal can never be higher than 0dBfs.
The software and hardware converts that 0dBfs into an analogue signal. That analogue signal generated from the 0dBfs digital signal can never be exceeded.
But what analogue level does a CDP and CVD audio and DVD video produce from a 0dBfs digital signal?
Your dynamic soundtrack can never exceed 0dBfs as far as I know. I don't think there is any expansion in the coding that can generate a higher transient than 0dBfs.
The software and hardware converts that 0dBfs into an analogue signal. That analogue signal generated from the 0dBfs digital signal can never be exceeded.
But what analogue level does a CDP and CVD audio and DVD video produce from a 0dBfs digital signal?
Your dynamic soundtrack can never exceed 0dBfs as far as I know. I don't think there is any expansion in the coding that can generate a higher transient than 0dBfs.
When I get home I can build some test tone video files so that you can check.
I've never seen a DVD or Blu-Ray that output levels different for CD and video, but that might exist. We can sure check it.
Any preferred formats for the video? Maybe Mpeg-2 for DVD and H.264 or WMV-9 for Blu-Ray? Remember that I have to keep the file sizes small to post them here.
I've never seen a DVD or Blu-Ray that output levels different for CD and video, but that might exist. We can sure check it.
Any preferred formats for the video? Maybe Mpeg-2 for DVD and H.264 or WMV-9 for Blu-Ray? Remember that I have to keep the file sizes small to post them here.
FWIW, I've tried not to make the math too dry. It's all pretty simple and should be easy to understand. The main hurtle is to get people to think "From the Top, Down" instead of "From the Bottom, Up". Digital is top-down. There is a hard upper limit, everything else must be below that.* That upper limit is easy to find, it's called 0dB full scale, or 0dBfs
Of course few things in life are like that, so we don't normally think that way - it's upside down thinking for most of us. Once you get it, it's not a difficult concept.
*except for some overshoot on a few types of signals.
Of course few things in life are like that, so we don't normally think that way - it's upside down thinking for most of us. Once you get it, it's not a difficult concept.
*except for some overshoot on a few types of signals.
Because it will tell you if your player outputs the same analog voltage from a CD or a DVD encoded at the same digital level. As far as I know, they all do, but this will allow you to verify that.
We also need to check the subwoofer output and any "Audio Management Modes" the player could have. Many HT systems use an active subwoofer crossover, so that needs to be checked.
I wasn't referring to you, this procedure is straight-forward and easy to understand.
I'm not sure if you get the feeling, but much of this confusion stems from the fact that people actually believe that there is a need for tens of amps to suddenly move a speaker cone. it's pretty obvious from the wording of some questions. there lies the actual problem, IMO.
Well, I guess there could be a sudden demand for amperage on a dynamic passage.
A dynamic sounding recording will have an average to peak ratio of 20dB or more. So a fast peak will need a lot more current than the musical average. We can easily figure out what that is, if we know where 0dBfs is. I don't think that a sudden 0dBfs peak would need more current than a steady state at the same level. Would it?
A dynamic sounding recording will have an average to peak ratio of 20dB or more. So a fast peak will need a lot more current than the musical average. We can easily figure out what that is, if we know where 0dBfs is. I don't think that a sudden 0dBfs peak would need more current than a steady state at the same level. Would it?
I have no serious reason to believe so. I agree with you.
but IMO many people think so.
why would you think that such expansion is going on? why would anyone do it? anyway, it's easy to check, just have few different levels in the sound track and measure at the analog output to see if the voltage is proportional.
I really, really doubt that any kind of expansion is done, DVD is a serious standard with audiophile target in mind, theoretically better than RedBook so it would make little sense to have such weird codecs.
It would be interesting data, for sure. But more useful -why? That isn't the point of the test. The point of the test is to find out what voltage levels you typically, or extremely, run. No matter the actual SPL.
The idea is to figure out how close to clipping you might be when running as loud as you ever do.
Well, obviously the voltage is dependent on SPL, and SPL is dependent on sensitivity. If you measure SPL directly you remove all those dependencies.
Then you can calculate volts from that. Current poll results:
2 volts or less 104 39.10%
Between 2-5 volts 92 34.59%
Between 5-10 volts 31 11.65%
Between 10-20 volts 16 6.02%
Over 20 volts. 23 8.65%
It isn't very interesting if the 23 people that listen over 20 volts are listening to 70 dB sensitive speakers, and it is perhaps interesting if their systems are putting out 110+ dB at that level because that is hearing loss territory. See what I am saying?
Hi Ron,
I don't think Pano is primarily interested in whether or not the DIY forum community is getting hearing loss, but on what kind of maximum amplifier output voltage level is appropriate for "normal" use. If you are more interested in hearing loss than in amplifiers, that's fine, but you are then investigating a different issue and therefore indeed need a different test.
By the way, for hearing loss the average power is more interesting than the peaks that Pano's test determines, and you also need to know how long people listen at those volumes.
Best regards,
Marcel van de Gevel
I don't think Pano is primarily interested in whether or not the DIY forum community is getting hearing loss, but on what kind of maximum amplifier output voltage level is appropriate for "normal" use. If you are more interested in hearing loss than in amplifiers, that's fine, but you are then investigating a different issue and therefore indeed need a different test.
By the way, for hearing loss the average power is more interesting than the peaks that Pano's test determines, and you also need to know how long people listen at those volumes.
Best regards,
Marcel van de Gevel
if you take 1000 random audiophiles and have them do the test, you'll know what power to aim for when designing an amp. if you're aiming to satisfy the majority, of course.
it's like saying that average age in a country isn't useful because it says nothing about average shoe size
A fast starting and a fast stopping transient will make the (crossovered) speaker demand more current than a steady state signal of the same maximum (peak) voltage.
a 100W amplifier can output 40Vpk into an 8r0 load and the current demand will be 5Apk.
That same 100W amplifier when fed with dynamic and very varying signals that do not clip will still output 40Vpk, but the speaker demand can easily exceed 150% of the steady 5Apk and often exceeds 200%.
On more rare music types the demand can exceed 300%, i.e. a peak transient demand of ~15A into an 8ohms 2way from an unclipped 100W amplifier.
That transient current demand depends on the fast transient NOT exceeding 40Vpk.
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Nicam is used in video signals. Near instantaneous companded audio get a wider dynamic range than the bits used for transmitting the signal.
If the test signal is below/above the threshold for that expansion then one could extrapolate the wrong results by simply reading the analogue voltage.
But I stand by my original thought.
had no idea what NICAM is.
Near Instantaneous Companded Audio Multiplex (NICAM) is an early form of lossy compression for digital audio. It was originally developed in the early 1970s for point-to-point links within broadcasting networks. In the 1980s, broadcasters began to use NICAM compression for transmissions of stereo TV sound to the public.
I stand too by my original thought. DVD is a modern audiophile standard. such expansion has nothing to do with fidelity. fidelity means, well, fidelity as in faithful to what's on the disc. DVD audio was initiated/supported by Meridian. I can't imagine such company even remotely considering compression/expasion.
but why feed idle speculation? choose a soundtrack and I'll make an image to be burned as DVD video, audio or whatever format you prefer. you make a DVD and test it.
http://documentation.apple.com/en/dvdstudiopro/usermanual/index.html#chapter=5§ion=3&tasks=true
The following audio formats are supported by the DVD specification and can be imported into DVD Studio Pro without using the embedded AIFF encoder.
MPEG-1 Layer 2 audio
Dolby Digital (AC-3) audio (mono up to six channels)
DTS multichannel audio (preview not supported)
PCM audio (pulse code modulation audio; used by the AIFF and WAVE formats)
of course, there is a non zero probability that a manufacturer decides to implement expansion in their player. same thing can go for CDPs, DACs etc. but I prefer to think that it would be a rare exception.
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