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Dynaudio Heritage Special
- Thread starter watchnerd
- Start date
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watchnerd
Grand Contributor
July 2020
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watchnerd
Grand Contributor
Helicopter
Major Contributor
57:00
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watchnerd
Grand Contributor
- Thread Starter
- #448
That's an interesting claim, that RFI gets into tweeters in some way that doesn't show up in ordinary tests.
It doesn't seem to match the test results of class D amps here at ASR.
Or at Stereophile.
At least not that I've seen.
But, I thought you were talking about the Heritage Special woofer, in this case, not the tweeter?
In fact, he says they're good for subwoofers.
OP
watchnerd
Grand Contributor
Something that sort of came to light a short while back when Amir gave the Elac UniFi 2.0 the run through is that with digital formats (and possibly depending on the music server program) the files (whether locally stored or web-streamed) can contain strong DC or near-DC (infrasonic) components, and that if you play such a file using an amplifier that passes DC ("dc-coupled") that the signal you send to the speaker will have a DC component, possibly a strong DC component.
Asking other people if they have the same problem with the same file is only likely to cause confusion, as has occurred in this thread. The other person playing the same file may be using an amplifier that blocks infrasonic frequencies. Or this may be done in the music server software they are using, or at some layer in the audio infrastructure on the computer, or possibly the DAC, etc. Even if another person says they see what seems to be the same as what you see, what do you then conclude? And if they say that they don't see it, what do you conclude?
What needs to happen is first some thought needs to be given to the unexplained motion of the speaker cone, specifically with respect to whether is seems to correspond to infrasonic content or even DC. If the hypothesis is that this is what is going on, then the file needs to be examined using some kind of spectrum analyzer, to see whether it does in fact have infrasonic or DC content. If it does, then you have your answer but still need to decide what you should do about it. If the spectrum analyzer does not confirm the presence of infrasonic or DC content but this is what your eyes tell you as you watch the cone, then you've got a mystery on your hands.
Asking other people if they have the same problem with the same file is only likely to cause confusion, as has occurred in this thread. The other person playing the same file may be using an amplifier that blocks infrasonic frequencies. Or this may be done in the music server software they are using, or at some layer in the audio infrastructure on the computer, or possibly the DAC, etc. Even if another person says they see what seems to be the same as what you see, what do you then conclude? And if they say that they don't see it, what do you conclude?
What needs to happen is first some thought needs to be given to the unexplained motion of the speaker cone, specifically with respect to whether is seems to correspond to infrasonic content or even DC. If the hypothesis is that this is what is going on, then the file needs to be examined using some kind of spectrum analyzer, to see whether it does in fact have infrasonic or DC content. If it does, then you have your answer but still need to decide what you should do about it. If the spectrum analyzer does not confirm the presence of infrasonic or DC content but this is what your eyes tell you as you watch the cone, then you've got a mystery on your hands.
MakeMineVinyl
Major Contributor
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watchnerd
Grand Contributor
- Thread Starter
- #455
I'm trying to follow your logic train here...
So if, hypothetically, my hybrid class A/D amp has more distortion than your class A/B amp....and I'm not seeing excessive woofer movement, and you are, because....?
Help me out, because I'm not mentally connecting the dots.
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Well I’m fairly certain when I played this track on my other system with the same results it is the track that’s the culprit.
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watchnerd
Grand Contributor
I wouldn't think of it this way, looking for "the culprit" per se. There is little doubt that it is something specific to this file, because this is the only file where you observed the speaker cone doing this, right? But knowing that it is something specific to this file does not give you a complete understanding of what is going on. If you run the file through a spectrum analyzer and you see infrasonic content or DC, you will then have a fairly complete understanding of what is going on, and will even gain the knowledge that the rest of the gear in the chain, the amplifier in particular, does not block infrasonic or DC content. If you don't have the means to analyze the spectral makeup of the file, there will be someone else on this forum who will have that ability and who will probably do it for you, but I don't know who it would be or how to get their attention. Maybe a new thread with the title: "Anyone got a software spectrum analyzer for analyzing a file I've got?" Something like that.