Those berillium tweeters will do a fine job of pushing that IM from your hi res digital down into the audible band for you. Enjoy that. 
Tim
Tim
Preference vs. audibility - please keep them separate.
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Those beryllium tweeters will do a fine job of pushing that IM from your hi res digital down into the audible band for you. Enjoy that.
Tim
Don't put your nose to close to those; deadly stuff!
I stick to ribbon tweeters. Non-toxic, respectable efficiency, and with an upper cutoff far enough up that it borders on silly. On top of that, they have a well-controlled impedence, which makes crossover design and integration a couple of orders of magnitude (literally) easier, and requires many fewer crossover components.
There have been some issues with broken diaphragms and people cutting themselves on the edges.
Most any kind of dome tweeter has a low-frequency resonance that can mess up crossover interfaces. It doesn't have to be, but it is most often true.
Very interesting. Would you say that this is an 'absolute defence' in any question regarding audible differences? So if it can be shown convincingly by measurement and/or calculation that any difference at the ears when listening at normal to loud levels would be smaller than the random motion of air molecules, then there simply can't be any audible difference? It does sound like a reasonable argument. At a stroke it might clear up the questions regarding RBCD vs. Hi rez, interconnects, power cords etc.
Well the absolute threshold of hearing can be found either in Stevens or in Fletcher. While they seem to disagree a bit, the big difference is that the ear canal resonance is in a different place due to different headphones, among other things. (Low frequency loudness growth is also an issue, there's still some debate there on what to think.)
The noise level of the atmosphere is very hard to refute, since it can be (and has been) measured by microphones.
Since the noise is in fact noise, were you to calculate the noise level in an ERB (filter bandwidth in the ear) from the atmosphere, and go 5.5dB below it (the level at which noise masks anything in that ERB) you'd have an absolute level that is below the masking level of the noise. You'd want to join the absolute threshold to that, and see what you come up with.
There is the perception that equipment can convey the emotion of music. The issue seems to be whether the reproduced material gets processes in the limbic system (which normally processes music) or not. This was discussed earlier.
I can't imagine why an amplifier (or any audio device) whose response extends beyond the audible range should sound any different from an amplifier that's limited to the audible range. Your comparison above isn't meaningful because one limit is +/- 0.5 dB and the other is +/- 3 dB. As long as both are flat within half a dB or so in the audible range, that should be flat enough to not matter. What happens beyond that range shouldn't affect the sound. If you play a CD for the source, its own response is hard-limited at around 20 KHz, so an amplifier that can pass frequencies higher than that won't have anything to pass! And good luck finding a speaker than can reproduce 100 KHz!
--Ethan
Some years back I had some experience with a phono preamp design (MFA Magus) that had an out-of-band EQ change at 50KHz, where the EQ went from a slope to flat at that turnover frequency. The designer did this to improve 10KHz square wave response. Universally, all the preamps with this construction were perceived as bright. Removing the 50KHz turnover and restoring the 'RIAA' slope (its not really RIAA as the RIAA does not spec the slope past 20KHz) eliminated the perceived brightness. On the bench the preamp tested with good tolerance within the RIAA curve up to 20KHz so I had/have no reason to suspect an actual frequency response error. I did not have sophisticated equipment at the time, so the assumption is that it was phase shift that was causing the perception. While we don't hear phase shift of a single frequency at all, from this experience I came to the conclusion that we can hear phase shift across a frequency band, perceived as a tonality. The 50KHz EQ change would have caused phase shift components down to 5Khz.
Reducing distortion seems to me more important than bandwidth, but if I can get the bandwidth I will go for it, as there tends to be less HF junk if the amplifier has linearity at higher frequencies. At the same time, my experience suggests that getting the bandwidth is a good idea, to avoid the possibility of a tonality induced by phase shift.
In case of fire it can be hazardous ,this is what scanspeak adds to their product
http://www.scan-speak.dk/docs/M10.pdf
http://www.scan-speak.dk/docs/M10.pdf
Were the listening evaluations blind or sighted? If sighted, all bets are off.
Even if the sound really did change, it can be explained by factors other than an extended bandwidth. Perhaps there was some in-band ripple, or maybe IMD as we've already discussed. Whatever the cause, if it's real, it is not unknowable. You just need to measure the right things. Or better, null the two preamps to see what's different.
--Ethan
People that knew nothing about the system/preamp had commented on it enough that the owner of the store asked me to take a look. It was only a problem on phono, FWIW, so I don't buy for a moment the idea that a DBT would have made it any more or less valid, since 3rd parties with no ax to grind offered their comments without being asked. The fix was to remove the equalization components responsible for the 50KHz turnover. This worked so successfully that the manufacturer incorporated that change into later versions of that preamp.
Of course if you measured the response of the phono section up past 50KHz 'before' and 'after', the change was plain to see on the 'scope. IOW, it was indeed the EQ change and the resulting change in frequency response at 50KHz that was being experienced.
Upon examining the preamp, I discovered the odd EQ components and asked the manufacturer what they were for. That was when he revealed to me that 50KHz turnover. It seemed logical at the time to see how it would work if the RIAA curve was restored at 50KHz and it was very obvious that that was the fix.
I don't doubt what you're saying, but given that no human can hear 50k, it had to be creating something, like your theoretical phase shift, within the audible range, because the range of human hearing is not in question. It is very well established, tested, re-tested. If humans could hear a change in frequency response at 50k, this is not something we'd be discovering for the first time in a phono preamp in a hifi shop.
Tim
Tim, what happens in space (way beyond Earth's atmospheric sphere) can affect climate changes on the planet's surface.
I think the point was to show how engineering of an audio product in the wideband can have a perceivable effect within a listener's hearing frequency range.
Bit like how alias/images in digital can (does not mean they will as it comes down to design) and possibly implementation of filters.
Cheers
Orb
Bats!
Tim, I am *not* suggesting that anyone can hear that high! What I *am* saying is that a rolloff (or in this case, rollup) at 50KHz can manifest as something audible in the electronics, due to the consequences of the resulting phase shift that occurs well into the audio passband; interpreted by the ear/brain system as a brightness.
Obviously to what the outside of the human (20/20) visual/auditive range (audio here) can do to its inside audibility.
...Perceptive and non-known influences.
In this hobby of ours there is some yet to be uncovered, and some we're aware of or/and on the right path of further elaboration and understanding.
New discoveries are made everyday and more to come. ...We got to be open to the balance between known and unknown.
- Ralph mentioned phase shifts in the human audio range coming from 50kHz, and even 100kHz as a multiple of ten seems to be the standard rule.
I'd say we're safe with audio components that can do from 1Hz to 300kHz in the most linear way possible with the smallest deviation permissible.
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Bats!
Tim, I am *not* suggesting that anyone can hear that high! What I *am* saying is that a rolloff (or in this case, rollup) at 50KHz can manifest as something audible in the electronics, due to the consequences of the resulting phase shift that occurs well into the audio passband; interpreted by the ear/brain system as a brightness.
I get that. Can it manifest itself in anything "better?" Or are we talking phase shifts, distortion artifacts, etc? What would be the advantage of having content up there?
Tim
I've no idea. But- if there is noise or distortion at those frequencies, as far as the electronics are concerned its probably best if they are well behaved so as not to make some contribution of their own. That is why its not so important for the speaker to have that sort of bandwidth but it is for the electronics.
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