toddc

Thanks for posting this article link Grif, it's definitely a good article! Frankly, I'm surprised at the number of people who are responding negatively on this thread who either haven't read the article or who are arguing with issues that were simply not discussed in the article. Read the article folks. It's amazing to me how many recordings these days have the recording level pushed. There was an article recently on how FM radio stations also push the transmittion level as much as possible in order to be the loudest station. Their tradoff is against quality. But listeners want loud. We all remember back in the seventies and eighties when making tape recordings of our favorite songs that we'd push the sound level to make them louder. The distortion and muffled sound was the risk. While it's great that someone has identified the parallel problem experienced in CD recordings (parallel in that it is the result of pushing the recording level too aggressively for greater volume levels) it is unlikely that studios will see the light. Most consumers play back on the cheapest quality equipment and the only difference they hear is loud or not loud enough. Sounds like longer term a newer technology like SACD which has built-in safeguards is required.

---------------- On 7/17/2003 4:07:17 PM NOSValves wrote: Man Tower records list 440 SACD that is more than I thought were even made ! Best Buy is cheaper though but they sure don't have 440 on there shelves here. ---------------- Actually, I think they have over 1000 if you count classical, which are in a different section. They try to keep the rif-raf away from the blue-bloods.

Amazon has them but they didn't set up the "neighborhood" properly so they're a bit tough to find. In the music section, click on DVD-A in the left column. Once there you'll find a link for SACDs in the center of the page. TowerRecords.com has a somewhat better section and selection, and perhaps also prices. From their homepage search for "SACD" and it'll get you to the right section. You can then view lists by genre, etc. You might also try elusivedisc.com acousticsounds.com

I've been trying to solve this for some time in my own cabinet without much satisfaction. I can either get airflow or quiet. The fans I've tried include a mix of different PC-style fans from 60 to 80 to 120 mm. All claimed to be super quiet. I've also got a laptop cooler which I use below an UltimateTV unit since they get hot on the bottom due to the hard drive. My next attempt is to try the panaflow fans. They are rumored to be the quietest, but we'll see. The one with the most promise is rated at about 21 db. The PC overclockers seem to be the ones with the most knowledge in cooling right now. One other thing you might experiment with is a variable DC adapter from radio shack. They have one that can be adjusted from 3-12 volts (if I remember correctly), and it has enough juice to drive several small fans. By dropping it down a step or two from the fan rating it typically reduces the sound level substantially. Please report back on any successes you have.

My apologies for disappearing for a couple days. Life got in the way and I received a new (vintage) tube amp from NOS Valves. But it appears the posts got much shorter as a side benefit of me going away. Okay, time for me to admit that jitter has the theoretical potential for more than absolutely zero affect. But aside from theoretical it is effectively zero. I searched on JAES and Jitter. Here's a succinct summary from one: ---------------- Although rarely observed in a well designed player, jitter is a worthy topic of discussion because of both its misconceptions and the large amount of press it has received. Jitter is basically defined as time instability. It occurs in both analog-to-digital and digital-to-analog conversion. The latter instance is the only concern here. Jitter occurs in the compact disc player when samples are being read off the disc. These reads are controlled by the pulses of a crystal oscillator. If the system clock pulse inaccurately (an unlikely event), if there is a glitch in the digital hardware, or if there is noise on a signal control line, the actual reading time will vary from sample to sample thus inducing noise and distortion in the extreme case. A great deal of money has been made by shrewd marketeers preying on the fears of the consumer worried about jitter. Such products marketed include disc stabilizer rings to reduce rotational variations, highly damped rubber feet for the players, and other snake oil remedies. However, the careful engineer has beaten the marketeer to the punch by having the samples read off the disc into a RAM buffer. As the buffer becomes full, a local crystal oscillator can then "clock-out" the samples in a reliable manner, independent of the transport and reading mechanisms. This process is referred to as timebase correction and as stated before, any quality piece of equipment will implement it. ---------------- http://www.tc.umn.edu/~erick205/Papers/paper.html#jitter Note that when he said "well designed" player he wasn't referring to high-end audiophile equipment, but rather "any quality piece of equipment" And from another site... ---------------- Does is matter whether I use optical or coaxial digital input when recording to Minidisc? Is jitter a problem? In a word: No. The perceived problems with optical interconnects relate to an optical cable's greater theoretical potential to distort the digital signal, particularly to create small inaccuracies in the arrival time of data bits ("jitter"). However, in Minidisc recording jitter is not an issue since the digital input signal's sample values are recovered and passed directly into a memory buffer or into a sampling rate converter that is clocked with the clock embedded in the input signal. The sampling rate converter and/or memory buffer allow the audio samples to be subsequently read and passed to the ATRAC converter with an accuracy determined by the MD unit's internal quartz clock. Even if jitter was an issue however, it is doubtful that the short cable lengths involved in home HiFi systems could produce audible differences between optical and digital cables. Regarding the occurrence of outright bit errors due to a marginal cable: S/PDIF contains only parity information, there is no error correction capability. If the errors are bad enough to cause bits to arrive with incorrect values, the likely result is that the digital audio receiver will not be able to lock on to the signal. A short paper by DJ Greaves goes into further detail about S/PDIF, and has some comments about why jitter is not a problem even in equipment without buffers. Another paper by Tomi Engdahl goes into great detail about S/PDIF, even giving schematics for AES/EBU <-> S/PDIF conversion. Finally, Digital Domain has written a very comprehensive paper on jitter in digital audio systems. ---------------- http://www.minidisc.org/faq_sec_4.html#_q34 Note that they refer to this as a "theoretical potential". That is the key point. We could stop there and go home. They continue however with a few additional points: First, it is doubtful it could produce an audible difference in home HiFi cable lenghts. Second, if errors did occur it would be unlikely that the signal could be decoded. In other words, you won't hear the highs rolled off you'll hear a skip. Third, they have guarded agaist any potential impact by using a buffer and clock on the receiving end (as I discussed in an earlier post). As one of the referenced links then goes on to say: ---------------- Even modern DACs have typically a small buffer and reclocking circuitry, so the jitter is not so big problem nowadays that it used to be. ---------------- So then the answer is not more expensive cables (*IF* you even believe jitter could theoretically have an effect on sound that is audible). It is to make sure you have a relatively current player that is not poorly designed by standard market definitions (not by extreme audiophile definitions). In other words, most any major manufacturer's player made in the last 5 years (10?). This makes sense. An engineer designing a component (say the DAC) would be able to see the bits coming in. If he was able to measure any data anomalies that flipped bits (corrupted words) then he would implement one of the solutions above. Actually, he'd implement them anyway since that's how you handle digital information regardless. That's how any engineer would solve it at any major electronics company. He wouldn't go out and buy monster cable and tell his boss his ears found the solution. My bottom line is this: if we can make a $3 cat-5 cable that works great for digital in the computer world where big dollars count on reliability, why would Audio need a $50 cable, or a $200 cable to send a digital signal. Please don't answer that. It's a rhetorical question and as said above by the professor there are plenty of great marketers who can spin up a great answer. However, if one still believes that jitter could possibly have an audible affect in their system then they should perform a simple double-blind test to demonstrate it and find a solution. Use three different cables and have some friends help you keep the test blind. Be sure and have some good wine, dinner and music selections on hand during the test; otherwise the evening will be a complete waste. I stick by my original point that everything prior to the DAC is basically irrelevant. Bits is bits. If your DAC is outboard or in your receiver then get a cheaper player, a cheap cable, and spend more money on discs. Cheers

I think you should give a play to the new RB-75. I know this group is all about heritage (I happen to have the forte's myself). But it might be that your friend likes the klipsch sound (not just the forte sound). For example, there was a review posted here not too long ago from Vacume Tube Valley magazine issue 19 reviewing the RF-7 and it compared extremely favorably to the Khorn. The RB-75 has the front port and the size you need. And I'd bet it has a pretty good sound. Personally, I'm dying to find an objective review. Have your buddy bring home a pair on trial and give us a report! I'll bet he keeps them.

To take the digital argument one step further: In a couple years even the cheapest DACs will be exactly equal to the best and most expensive. Don't worry, they'll still charge more for some. Two Reasons: First: Digital recording methods like DVD-A and SACD are capturing so much data that there is little room left for interpretation by the DAC. The artistic/mathematical interpolation component of the DAC is gradually (rapidly) going away. If the definition is very specific then the re-creation is very specific and predictable. Second: Writing software and creating electronic chips is expensive work. If you write a really nice program you use it. It actually costs you more money to make a second version that isn't as good. And, after you finish software it then it costs you nothing to reuse it a million times. It'll just be cheaper for companies to use one version. At that point, all audiophile sound quality will be defined by the components after the DAC. Keep a hold on your Klipsch.

The contradictions in jitter are getting painful. I'm lost. So have we proven bigfoot exists, or not? A quote from earlier in this thread: "Sure, even the cheapest portable CD players have buffers to handle misreads. Doesn't change the fact that their crap DAC's absolutely destroy the high frequency information output to the headphone amp." Okay, so we all agree then that we can get the data off the disk and place it in the buffer without problem. We have it sitting there in the buffer ready to send across our cable to the DAC. The buffer has a bunch of little holding spots lined up in a row that hold all those 1's and 0's. Are they still in the right order? Were extra 1's and 0's inserted in between? Remember, the buffer can only store 1's and 0's. It puts them in a row. It can't comprehend anything else. Is it after the buffer that the Mr. Jitter sneaks in? Quote: 44.1Khz is 44,100 samples per second...Still think audio signal transfer is a small amount of data? Well, for kite string it's too much data. But YES for cheap digital connectors it's pretty freakin trivial. Remember, even the cheapest cd portable player can get all the 1's and 0's off the cd and to its DAC. When it doesn't you hear a skip. When it sounds lousy, it's because the DAC and/or everything after it is cheap. Quote: For added fun, you start interpolating 1's and 0's ...one sample word being changed from 1001 1101 1111 1001 to 1010 1101 1111 1001 Okay, let's agree to not use the word Interpolating in our discussion. It sounds neat, but in some usage it means "inserting extra", or "altering", or "interrupt", or in mathematical terms it is "estimating a value that lies between other values". For a DAC we usually talk about interpolation because we have these rough points (digital) that we want to connect with a line. It's the DAC's job to draw that line nicely so things sound nice (a lovely wave). SACD is cool becuase those points are so close that there isn't as much estimating for the DAC to do to recreate our sound. You can critize my analogy of a dot printer simply because all analogies break down in reality (that's why they are analogies) but it is exactly the joining of points of data that I was describing that create the appearance of continuous data. It is the fact that DACs cannot accurately recreate the wave when the points are too crude (or far apart) that creates the problem. Not enough information. For example, I've just drawn a sound wave on a piece of paper. Below are the two points used in that sound wave. Please recreate exactly the sound wave that I drew here at my desk. Begin . . Now, back to your example of bits being changed from 0 to 1. If this is happening to the digital signal then we can measure it by either writing the data out after it was changed, or measuring the data at any point in the process by looking at it (not looking at the transmition pipeline but at the data!). Why doesn't someone compare the data and show it to us. All the charts measure the transmition medium and ignore the data. But we know you can tap into a system at any point (say at the end of the cable) and look at the data. Why don't we just do that? Okay, earlier we agreed we have a buffer at disk reading. Why doesn't someone invent a buffer at the DAC? That way we could cue up all those 1's and 0's and make sure they don't get sliding along too fast. This buffer could be just like the other one and simply store things in discrete slots exactly in the order received. We could compare the memory in this buffer to the first one as a test. Then it would be up to the DAC to decode and play the bits in time. It could use its own timing definition to pull the data and translate each bit, and use it's logic for the definition of what each value means. Finally, as for the many great links provided above they don't even seem to agree on what jitter is or how to measure it. Is it the pits on the disk being too shallow? Sounds like the read buffer solves this. Is it the order? In any case, each one had a good solution to sell. I've found an equal number of links to sites that claim to increase the size of your ding dong. That makes it true, right? Haven't found one yet featuring Mr Katz, so maybe it's true that he's already well hung. My favorite part from all the links was where he talked about the potential for cumulative effects of jitter. He takes a cd and makes a copy of a copy of a copy 99 times and then does a *listening comparison* between the first and the last. He says "Well, most people listening to this CD can't tell the difference" (seriously!) No joke sherlock. But why did you bother listening. It's data. Digital data. You can MEASURE if the copy is identical. It either is or isn't. Why doesn't he discuss how different the data was on the copy. I mean, all that fancy measuring equipment he talks about and the one thing he wants to measure he ignores. Mr Katz is either sitting in his living room laughing his tail off that we're discussing his article, or sitting in the basement rubbing his hands together and laughing manically. Good news though, he's coming out with "The Jitter Bible" (again, no joke) that will probably answer all your questions for a small fee. He's busy lining up product placements. All in cheerful camaraderie,

As Artto just said in another thread: ---------------- SACD is a ONE bit system. No decimation filters. No Delta Sigma modulator. No Interpolation Digital Filter. No 'brick wall' filters. Sample rate is 2.822MHz (2,822,400 samples per second) ---------------- Very, very tiny dots indeed.

You've really added a lot of information to your original post. Good discussion. To touch on your last paragraph... ---------------- Likewise, you can recover the digital datastream from a CD with 100% bit accuracy, transmit that signal any number of ways, and again recover it with bit 100% bit accuracy. However, if you take two identical datastreams, one recovered from a high jitter source and one from a low jitter source, they can *SOUND* quite different. ---------------- Jitter would not affect the sound quality. The reason is because CD's are designed to be un-encoded at a specific rate. You can't change that by pushing the 1's and 0's at the DAC faster. You can't crowd them together either. It's either a 1 or a 0. If you slow them down the DAC doesn't care - as long as you don't drop below playback speed. If you drop below playback speed then the whole thing goes BLURP. Not subtle. When copying a CD from computer it can read the entire disk and write a new disk in just a couple minutes. Obviously we don't listen that fast. And the DAC won't decode it faster like playing a 33 1/3 lp's at 78 rpm. The really fabulous thing about digital is that it is so perfectly defined. There is no chance for ambiguity in the "value". The ambiguity comes when we convert the digital value into analog. To use your printer analogy we could use an old dot matrix printer. The dots weren't very tiny so you could see each little dot that was printed to created the letter A. Each dot is a digital bit that is used to create an analog image of the letter A. Today we have laser printers that have 1200 dots per inch. These dots are so tiny that our eyes perceive the analog image of A as perfect and without any jagged edges. The argument with CD technology is that the dots are too big and as a result there are a number of people who can hear the rough edges (just like seeing the dots on old printers). That's why they're now releasing DVD-A and SACD which have much higher resolution (very tiny dots).

Exactly. (well, except that part about "real time") A checksum tells you that all the 1's and 0's arrived or didn't arrive. It also tells you if someone changed a bunch of 1's to 0's, or vice versa. And cd players typically do have an error checking process as they read the data off the disk to see if it skipped. Trivial stuff. Cheapest players. Then you move the signal in its digital form from the player to your DAC (perhaps the DAC in your receiver). To do this it goes across a cable in digital format. Trivial stuff. Cheapest cables. Why, because there aren't 40 million other users jumping back and forth between those two devices over a shared cable. It's a dedicated single-purpose system. Trivial stuff. Cheapest systems. It's the same reason why you can by a dedicated dual tray CD player/copier and make exact copies of discs all day long. The wires inside those things cheap. Every copy will be perfect. It's the DAC where things get interesting. That's the money side.

And the fact that you know we'll all be seeing the images exactly as you created them confirms that you believe a digital signal (in this case an image) can be transmitted over long distances with very cheap wires and will come out exactly perfect on the other end, without any coloring or alteration based on the wire I'm connected with. (very big grin) If all the 1's and 0's arrive then you have a PERFECT copy of the original. YMMnotV.

It's interesting to note that both examples are displayed in an essentially analog format (image). You and I recognize it as text but the computer recognizes it as a picture. It'll take text-reading software to convert it back into text from image format - which is essentially a step identical to A/D conversion or DAC. When the text is jumbled like this then it makes it much harder for the text recognition to work (A/D conversion). That's why everything should be kept digital.

What about pairing the new RB-75's with a meaty subwoofer? Has anyone heard them or found a review anywhere? Do they meet the old klipsch standard?

Ray, I was being a bit sarcastic, although it was directed at the topic not at you. It's not clear from this thread if you're discussing the impact the cable has on a Digital signal or an Analog signal. I'll concede they are very different and my comment was related specifically to the digital signal. If I read you correctly it sounds like youre discussing using an analog measuring device to look at the transmission of a digital signal, yes? My point was that if youre sending a digital signal you can very simply compare it to the original. An exact copy means success. If any 1s and 0s are missing then you have failure. Completely objective and quantifiable. Whatever else is happening in the cable is irrelevant. To use an analogy, if I'm typing right now on a DSL connection I'm sending a digital signal to the internet over my phone line. If my wife starts talking on the phone at the same time then a meter will measure more "stuff" on the phone line. There are several things happening in the wire that can be measured by an analog meter, but the digital transmission of my typing isn't warmed up by her pleasant voice talking on the same wire. And, the typos are still all MY fault. Similarly, a digital signal sent over a high-end digital interconnect will sound exactly identical to one sent over a cheap digital interconnect -- IF all of the 1's and 0's are getting through both cables. Usually, even cheapest cables meet this bar. To take this to the strongest point, the quality of ALL components prior to the DAC are irrelevant if all of the 1s and 0s are making it from the disc to the DAC. This is trivial with even the cheapest components today. Take the cheapest CD drive and plug its *digital output* into your high-end DAC using a $1 cable and the sound will be identical to a $2000 CD player sending its *digital signal* into the same high-end DAC over a $500 interconnect. Talking about anything else that can be measured on the cable in this digital signal scenario is deceptive and irrelevant, isnt it? A digital signal is just data.