gerbache

In practice, interpolation will result in a slightly different signal than a non-interpolated one. As to whether it's a better signal than the original, that's up to the listener to decide, but it will be slightly different, depending on the method of interpolation. With any PCM encoding of a signal, there's a set amount of noise caused by the number of bits of quantization. As you increase the number of bits, this level of noise gets lower and lower, until, especially with these newer 24-bit ADCs, the amount of noise added from the quantization is below the noise floor of the analog components backing it up. In other words, the quantizer isn't adding any appreciable noise on its own. Now, as I mentioned, the number of bits basically sets the amount of noise present. The sampling frequency will basically set the frequency at which that noise appears, because the actual value of the noise will be different at each sampling point. When we use these really high speed, 96 kHz or 192 kHz ADCs, the frequency of the noise is largely pushed out to the realm of 40+ kHz, which is inaudible to humans, so as was pointed out, we don't notice it anymore. The biggest benefit of this is that any ADC (and consequently, DAC) that performs at this rate is going to have very little noise present at any frequency that matters to us. By upsampling, we're attempting to change the signal so that we can take advantage of these benefits. It's entirely possible, depending on the manner in which the upsampling takes place, that it could cause an audible benefit that you don't get with a non-upsampled signal, even though the input signal is the same. With a lot of these new ADCs, the limiting factor in things like frequency range and SNR is in the analog electronics around them, so it's not quite as important to have a super ACD.

I should have read Max's post before making that response..his explanation of how upsampling works is actually spot-on, and much simpler than what I said. In a nutshell, an upsampler smoothes out the spaces between each sample; if it does a particularly good job of it, it could potentially have a benefit on the sound output.

A quick pedantic note on the way upsampling works: Even though you're right, no new information is added to the signal when you upsample, it doesn't just double each value. It performs an interpolation between the two values, such that rather than being the same as the value preceeding it, it'll be in between the previous and next value. I haven't looked much into the technical method of how they upsample in these players, but they're probably doing some relatively sophisticated methods of interpolation that may have some impact on the sound at the output. It's also worth pointing out that many upsamplers out there nowadays aren't increasing the frequency in integer multiples, so it has to provide a different method of mapping the new values, which I will almost guarantee is some form of interpolation. In any case, upsampling can actually have more of an effect on the sound than simply doubling the sampling frequency, even without any "real" extra information. Whether this is an improvement or a detriment to the sound would depend on how they do the interpolation, but you're right that upsampling doesn't really create any more data from the original source than was encoded on the CD.

Canon's lower end models get really good reviews. From my experience, they're really well made and easy to use. The Rebel cameras are nice, and nearly as feature-filled as the next line up (the EOS series, if I remember correctly), which basically buys you a more sturdy body build. One nice thing about Canon is that their lenses are in a really broad range of price, from the cheapie stuff they give you with the camera all the way up to the huge, professional lenses you see at sports events. One lens I really like (if you're willing to sacrifice zoom capability) is their 50 mm, f1.8 lens, which can be found for around $50, I think. Super sharp pictures, if a little cheap feeling. Nikon's lens lineup is pretty similar to Canon, since they are both in consumer as well as professional cameras, but the Nikon lenses seem to go a fair amount more expensive than the Canon. If you want to go a cheaper, but solid way, and she is willing to learn to use a non-autofocus camera (it's not that hard, although I admit that I have an autofocus body myself, in addition to my old manual), you can find older bodies of Nikon, Canon, or Minolta for pretty cheap on Ebay, and can usually snag a body plus an assortment of lenses for that kind of price range. I like the older SLR bodies, personally. My old Minolta is built like a tank, and has survived more torture than I figured would be possible. These old cameras will take pictures that are at least as good as, if not better than the newer models, plus a quick way to learn the ropes of SLR photography is to have to do it a few times with a fully manual camera.

---------------- On 6/26/2004 1:08:53 PM Marvel wrote: If the source and load are equal impedance, you will have the maximum power transfer. If the headphone output were 50mw, the amp (if the same impedance as the phone amp) would only get 25mw. As the load impedance increases, the efficiency will go up, but the power transferred will actually decrease. IOW, you probably won't get too high a signal to the power amp, considering the high impedance of the amplifier input. This is a standard textbook way of looking at impedance matching, but in general, amplifiers like this don't follow this rule. Normally, you want your amplifier output impedance to be considerably lower than the load impedance. In addition, you can find headphones that range anywhere from 32 to 600 ohms, so it would be next to impossible to design a headphone amplifier such that it is "matched" to the headphones. It turns out that if you look at the way these amplifier circuits work, you actually generate maximum power when your output impedance of the amplifier is as low as possible. That being said, some years ago, a "standard" was designed proclaiming that all headphones should be able to expect a 120 ohm output impedance regardless of the impedance of the headphones themselves. I'm not sure how often amplifier manufacturers follow this standard, but nonetheless, many headphones are designed with this in mind.

---------------- On 5/26/2004 6:32:08 PM garymd wrote: You should hear the original mixes of Anthem Of The Sun and Aoxomoxoa. Very different. More spacial if you will. They're hard to find since they were pulled from the shelves very early on but I have a DJ friend with both. Very cool stuff. Do you know anything about the white cover vinyl release of Anthem of the Sun? It's a different mix that really has a different sound from the widely released version. My dad has a copy of it, but I've only heard it once, so I don't really remember all that much about it. Think that might be the mix you're talking about? I need to borrow it from him and make a copy of it for both of us...

Live/Dead is a great intro to their live shows, especially from the earlier days. In the Dick's Picks series, probably my favorite is Volume 4. Don't remember which year it was from, but it was recorded at the Fillmore East and has some of their best live stuff I've heard. The entire Dick's Picks series is well worth a listen, though, and is really pretty reasonably priced when you consider the amount of music they all include. That being said, I'm a huge fan of live Dead music. Some people aren't at all fans of the Dead, but will really get into the more accessible stuff like Workingman's Dead. You really just have to give it a chance, though. I will have to say that their first few albums (Anthem of the Sun, Aoxomoxoa, for example) tend to not be quite as accessible as their later ones. At that time they were trying to emulate their live sound in the studio, and it just doesn't work quite as well. I really like their first few, but I can easily see how it wouldn't be the best intro into the Dead.

They're making home networking solutions now which use the AC power lines of the house as a cheap, easy way to connect all the machines. The way I see it, yeah, it's a really simple way to get the problem solved, but there's enough noise on the line without me adding to it. Speaking of noise, I have a light in my new apartment right now that has been going nuts, looking like the voltage is fluctuating WAY up and down. Off to go see if I can find the cause for this one...

I'll throw in another recommendation for the Hsu VTF-2. Great little sub for 2 channel only use. I'm running it with my heresies right now. Most of the time I don't even notice that I have a sub in the room, unless for whatever reason, I have to turn it off. Suddenly, the whole system just seems to lose something. It seems to reach down as far as I could ever want for two channel purposed, and definitely far enough for jazz/classical. I'd highly recommend it, plus the price is pretty nice (right around $500, I believe). Mine is one of the original designs, so I can't comment exactly on the new model, but I can't imagine that it's any worse, and probably a whole lot better.

---------------- On 4/22/2004 7:53:33 AM mdeneen wrote: I agree with Ray on the economics, and I think there is merit to the headphone sans room acoustics arguement, although I would never want to do all my listening through 'phones. Ray, do your Sennheisers suffer the "constantly intermittant connnectors" problem? Perhaps it's me, but every pair of Senns' I have owned, within weeks the tiny connectors go intermittant. I think their cable is the WORST design I have ever seen. Those connectors are crap for one, and the "cowboy hat" style dual-cord under your neck has got to be the most uncomfortable style possible. Great 'phones, somewhat cheesy design, IMO. mdeneen ---------------- Don't they use that style of wire because you're supposed to be able to change them? My dad has a set, and I vaguely remember seeing something in the book that came with them that you can buy other wires to "upgrade" the ones that are built in. Not that this makes the dual-cord style any more comfortable, but at least it gives an opportunity to get rid of a staticy set. I don't think dad's are staticy, but then I haven't heard his in forever now. I suppose if you're paying the money that Sennheiser costs, you ought to be able to expect a set that doesn't need to have new wires added on, though. Anybody have any other favorite headphones? I might be in the market for some in the near future, but Sennheiser are the only top notch ones that I'm familiar with (and can possibly afford).

It looks like it does a different type of upsampling. The 795 upsamples to 24 bit, 176.4 kHz, while the 963 upsamples to 24 bit, 192 kHz. Honestly, I'm not sure if this makes much of a difference, but 176.4 is just a multiple of standard cd audio, so it is probably a less sophisticated type of upsampling. As for whether it makes a big difference or not..well, I don't know about that. Honestly, I can't hear a huge difference between the upsampled and non-upsampled audio on my 963. The product specs for the 963 are definitely more upscale than the 795, with stuff like separate video and audio sections and a more impressive sounding video decoder, but then if the product specs weren't much more impressive sounding, I'd really wonder about Philips, considering the 963 costs twice as much. I'd be really curious to hear if someone tries to compare the two. I like my 963, but the convenience of a 5 disc changer is really nice to have, as well.

Sadly, THD is not really a good measurement of sound quality. Pretty much any amplifier you buy these days can be made with an impressively low figure for it, so many people cease to use it as a guideline. If you look at some of the tube amplifiers that are very well regarded, the THD figure can be up in the several percent range. In other words, if it sounds good, I wouldn't worry too much about what the manufacturer quotes for THD.

*****es Brew is a tough one to listen to if you aren't a fan of that type of music. It seems to be an album that people either really like or just realy don't get. I wouldn't base you're entire opinion on Miles Davis on that one, anyway..

If you aren't opposed to using a subwoofer, you can fix the big problem with the Heresies pretty easily. I'm running a Hsu VTF-2 with mine, and it blends well enough that it really sounds like the Heresies just suddenly reach down to the 25 Hz region. What's really amazing is when I turn the mains off and just listen to the subwoofer's output. The thing is barely on most of the time, but the speakers sure sound a lot bigger! Granted, I could probably have gotten the bass I wanted by just getting the Forte's in the first place, but with the subwoofer, I do get bass down a bit lower than Forte's can manage, so it's all a tradeoff.

---------------- On 3/23/2004 1:38:06 PM Griffinator wrote: Fine. DVD-A is better because it uses multibit delta-sigma modulators that are capable of employing dithering and optional noise shaping to remove digitization artifacts from the stream. A true 1-bit delta-sigma cannot employ such technology - how exactly do you dither one bit? You can't. That's why I stated that "1-bit delta-sigma sucks" Not that d-s converters are a bad technology, but rather that single-bit d-s converters are a bad technology. No one, not Burr-Brown, not anyone, uses 1-bit converters anymore. It's oversampling and dithering, both of which have made a positive, not negative, contribution to the fidelity of digital audio. For Sony to declare that these functions are a bad thing? I guess they're hoping we've all forgotten how utterly bad the first CD players sounded. ---------------- I haven't heard Sony declare these things bad. They're still doing plenty of noise shaping and such on the DSD signals. DSD doesn't just involve a straight 1-bit delta-sigma modulation. Sure, the final result of the whole deal is down to a 1-bit message, but there's a lot more to the technology than just a simple delta-sigma modulator...