Welcome to the July meeting for the insatiable tweak. Hope all of you other people running tube amps have sufficient air conditioning for your listening rooms. One of the best things I did a couple of years ago was to install a groundwater heat pump whole house heating and air conditioning system. While my amps do keep the room toast warm in the winter, summer listening used to be a real miserable time with the room either sweltering or the window air conditioner producing sufficient noise to ruin the experience. The groundwater in NH is at a steady 55F degrees, and the heat pump only raises or lowers that temperature by about three degrees, while cooling or heating the whole house. It also is very energy efficient as it uses only about 1/3rd the electricity of room air conditioners or electric heat, and in winter costs me less than my old oil heater did. In addition, the electric company changed the wiring from the road to my service to accommodate the system, for free, which somewhat improved the electricity feeding my media room. Such a deal. Thus, I'm saving the Planet (maybe) and enjoying my listening time more.
A couple of weekends ago I had a very fruitful visit from Roman Bessnow of Boston, otherwise known as "Romy the Cat", who is the owner of Good Sound Club. Roman, like me, is a horn loudspeaker freak. Unhappily, my system was not up to its optimal as the two tube amps usually used on my main speakers were out for repair and a pair of Denon POA solid-state amps were being used until they were returned. Wish I had saved all of those beautiful tube amps from the past. Anyway, He must have some of the best ears in audio, as within five minute of listening to my system with the new RAAL tweeters he had figured out a problem I had been having in tuning them, and came up with a couple of suggestions on how to improve the situation. One of them was one of the cheapest tweaks I've yet seen; placing a single sheet of paper towel in front of the tweeter. Most of the harshness I had diligently been trying to remove using the crossover and volume controls was erased. For the past couple of days I've been perusing The Good Sound CLub and and have gained much more knowledge there than in most of the hours spent at Audio Asylum. Give Good Sound Club a look-see.
Anyway, back on topic, continuing my articles on building a home theater computer and server to high-end standards. Over the next few months (unless interrupted by new and exciting equipment to review) we will discuss this and in each article add-ons which will enhance the experience. Please review AA Chapter 101 for the preliminary discussion on this topic. Today we will discuss why this is a worthwhile money and space-saving project and let you in on where and who has advanced the possibilities of this equipment for high-end audio.
While I have used computers in the past for audio and video, until now I've settled on the standard software available to all Windows PC users, such as Windows Media Player, Media Center or WinAmp, using a fairly well-built computer with only an external semi-pro soundcard for their improved sound over the motherboard's outputs or the standard soundcards available. While the results were pretty good, and came close, at least with audio, to what I could obtain with high end disc players, both CD and DVD-Audio, they couldn't quite match the sound from a true high-end player like my Esoteric DV-60. Why?
First, until Vista was released it is no secret that Microsoft's Windows had a problem in that all digital audio information had to go through a so-called K-Mixer that changed all audio to 16-bit/48kHz. The only savior was if you had a sound card and software with the ability to do ASIO (Audio Stream Input/Output, in which a soundcard driver protocol for low latency high fidelity interface between Windows and a soundcard eliminating the K-Mixer). The soundcard could then change it back to its original bits but that required two changes that damaged the sound. Luckily, this has been changed in Vista, which allows one to circumvent this fidelity destroyer.
Second, Windows has many different programs running in the background to control the various control processes. Like our bodies, the more processes that are running, the less the brain can concentrate on the music. One need only open the Task Manager and look at all of the Maintenance Applications and Processes running in the background and check out the Performance to see how much of the RAM is taken up by them. On the negative side, Vista has added more processes to gum up the central processor's functions and RAM.
Third, all of these programs take the music digits from the hard drive; run it through the main processor and circuits on the motherboard to a built-in or add-on internal soundcard, adding jitter. While the hard drive probably functions with less jitter than most disc drives, the best possible option would be to have the bits stored in RAM for the lowest possible jitter.
Fourth, while one can use the disc drive to play back music, one loses the ability of the computer to store as many discs as you want, your entire collection even, thus allowing one to play back any selection at any time without elevating one's butt from one's favorite listening chair. One can store the music in its original bit form or use a so-called lossless program, such as FLAC to decrease the storage space by 15 to 30 percent. I prefer to store as original bits, as storage has become very cheap, and why put the CPU through further processing to get back to the original bits while the music is playing, adding extra work for the processor. Unhappily, most if not all of these programs will read the disc only once, copying the bits as they are read by the mechanism, thus not correcting for any errors that may occur during the read process. No disc is perfect, and bits can be lost, the effect of which the playback software tries to compensate for by interpolation. Better would be a perfect read of the disc. For those non-believers who think every bit is read perfectly the first time around, using a program discussed below, while copying my CD collection to a hard drive, there were at least 40 out of 200 of my favorite discs that needed multiple passes to capture as many bits as possible, and still had misses. Guess the old CD was not "Perfect Sound Forever".
Fifth, the inside of a computer is one of the noisiest RF environments known to Mankind. All of that noise can intermingle and damage the transport of the bits from the playback mechanism to the output or D/A converter if they are not properly shielded. If one could control all of the above, there would be no reason why a computer couldn't function as an excellent high-end audio playback system. In fact this system could equal the best digital audio components out there, as they are superb at storing and retrieving digital information. In addition, there are excellent professional and semi-pro soundcards available that are being used to produce many of the digital recordings made today.
Home theater computers can be used for all sorts of functions that would require multiple pieces of equipment to accomplish, such as:
1. CD playback. Why it can be better than almost any dedicated player will be discussed.
Enough with the introduction. After a five year hiatus of experimentation with HTPC's due to the poor quality of the Microsoft Windows operating system, plus the lack of interest in software and hardware manufacturers within the audio community. About six months ago, I decided to get back into trying to bring a home theater computer up to high-end audio standards. This interest was brought about by several things. One of them was the Nova Physics Memory Player, a souped up superb sounding but expensive computer showed the potential of HTPC's (also the possible cost). Second, the ability to play back DVD-Audio. Third, the arrival of the ability to play back lossless DTS-MA and Dolby HD concert recordings. Fourth, the ability to record and store high definition audio and video recordings. I questioned whether a hobbyist could come close to if not exceed high-end standards for a reasonable expenditure of time and expense.
After a couple of months of experimentation with a Sony Home Theater Computer I had picked up on the web, with less than stellar results and about ready to give up on the project, I happened upon a set of discussions online. Y.N. (he wishes to remain anonymous) with an I.T and Physics background had worked out the problems associated with using a computer for audio playback. As he felt that his results were significant, he decided to share it with the audio fellowship to help others. As a result, he obtained much feedback which improved upon his original work, which he now calls the "cics Memory Player (cMP)".
To summarize his methods:
1. Use a horizontal chassis with a built-in LCD screen such as those produced by Zalman, which allows it to fit in with the rest of your equipment, and gets rid of an external screen with its noisy graphics card (except for video playback).
2. As few cards and peripherals as possible except for external hard drives.
3. Shielded high grade wiring.
4. Two separate power supplies to separate noisy drives, fans, etc. from RAM and CPU.
5. Remove as many Windows Applications and Processes as possible to free up RAM, as this decreases the activities the CPU has to keep track of and clears the computer of both noise and blockage of the transmission lines for information.
6. Use a high quality DVD transport to bring the digital information into the computer.
7. Storage of the bits on internal hard drives for later playback.
8. Add RAM to the maximum of 3.6 GB that 32-bit Windows Vista can handle. With the decreased use of RAM by the eliminated processes and the extra RAM, with the proper programming one can store either an entire upsampled CD or a DVD-Audio to RAM before transmission to a DAC. Thus, almost eliminating jitter as a factor for degradation of sound. (Y.N. disagrees with me on this point as he feels that allowing for only 1.0 gig of slow RAM for playback decreases noise in the computer. I have many 24-bit at 88 and 96 kHz files that require more RAM, thus the benefit to the maximum that 32-bit Vista will run.)
9. The ability to use only the cMP program in a Windows shell, shutting down Explorer and all other programs, thus freeing up more RAM.
10. Using a recording program that keeps reading a disc over and over until it can extract as many of the bits cleanly as can be obtained from a disc and either places the information in RAM for immediate playback and/or into hard disk storage.
11. Use a playback program that will upsample the data to the highest level that the playback chain can process.
While his work has been done primarily using Windows XP, which he feels is superior to Vista for this application, he uses the Zalman chassis and internal hard drives, I have been experimenting on using most of his improvements with Vista and a standard upright chassis and external 500 gig e-SATA hard drives with separate power supplies. This allows me to only turn on those drives that will be used during a listening session. In addition, the computer has been optimized for DVD, Blu-ray, HD-DVD, and DVD-Audio playback, and will discuss this in next month's column.
In the meantime, please review the following websites for the Memory Player's information:
I emailed Mr. Y. N., and he sent along some interesting information on how the project came about:
Cics is just an arbitrary name and has little relevance to me. Please do not print my name in your review - I'm willing to share my personal details if people want to contact me via email but don't want any part in media publicity. It's just not my style.
Regarding your query, here is a brief summary:
2. AOB Computer Tranports 0.1 paper was created as I saw far too many complexities for doing a good setup. My IT & Physics background helped greatly but even so, what needed to be accomplished was hard. Given the great results, I felt compelled to share it (and make it easy for non IT literate people). The other big reason for doing this was to get others' experiences in computer audio - this feedback certainly paid big dividends. I learnt a whole lot more.
3. AOB Computer Transports 0.3 paper - significant improvements and deeper understanding of digital audio (upsampling).
4. cMP (Memory Player) - Yet more improvements to version 0.3. The paper gives rationale for the work. For me its getting sample streaming to the soundcard as efficient as possible. There's far too many things happening in Windows and cMP addresses these unwanted activities, provides a cleaner electrical environment, and I wanted remote convenience (done elegantly and not via some cumbersome laptop via wireless arrangement). RAM playback: I tried getting foobar developers to change their design to do playback from RAM - no joy here, so this got me started on cMP's operating software which loads wav (or other audio content files) into the Windows system cache which prevents HDD traffic interference during playback. It is a work around to foobar. Finally, audio players are multi-threaded animals and optimizing this gives improvements. All this is done in cMP's software.
5. Jitter Research, Analysis & Measurement paper. This is very exciting stuff. I wanted to understand why my Scarlattic Clock came off second best to the cMP. Measuring jitter showed a superior performance without the Clock! This is a technical piece of work but hugely insightful in designing digital audio players.
6. cPlay (stereo audio player using ASIO only). This is my current work and the last big piece of the puzzle for a complete ultra high-end player. It complements cMP handsomely and achieves lower levels of optimizations in Windows (when using cMP). Foobar's design does not allow for this, which got me to think how I could build one. Jitter Research above informs the broad design for cPlay. Eric da Castro Lopo (creator of SRC) also gave me a heads-up on his new work that ultimately motivated cPlay. It's at version 1.0b6 - the core playback design was fully operational in two weeks and has since seen subtle but important refinements. When I played the first CD (Tracy Chapman) via headphones from Juli@'s soundcard, I was stunned at the amazing sound quality! The feedback I've received on cPlay is just awesome (especially from highly experienced people). cMP with cPlay is an amazing sonic experience. The next beta release will do FLAC. All the papers, etc. is available at AA. Please give cPlay () a try and let me know.
Here is the most amazing thing: cMP+cPlay is the lowest cost item in my reference setup and yet offers the most significant sound improvement. My wife and 2 daughters have been hugely supportive of my hobby for which I'm very grateful. Sharing my work with others is my way of giving back. Besides, this is so much more fun than vegitating on the TV sofa!
Pinnacle PCTV HD Pro Stick
So how did it work? This is the first unit that I know of that will do all five types of reception, including FM and ATSC high definition television. On my HTPC, ATSC 1080I high definition programs looked as clean as with the unit's built-in video input card, and attached to both my outdoor UHF antenna and my DirecTV receiver I could find no difference. While the Video Spin software was a little more difficult to use than my Ulead type for editing, storage and recording, it did work without a glitch. FM classical music sounded significantly better than what one can get off the web radio stations, but even with my M-Audio FireWire 410 audio card, couldn't quite match what was possible with a good FM receiver. I don't have cable, but high definition programming from the DirecTV receiver down-rez'ed to 480I looked as good upsampled by the computer to 1080I as what I get through my DVD recorder. Programming could be stored indefinitely on the computer's hard drives or recorded to DVD for later playback. The only drawbacks are that anything other than off-the-air high definition cannot be recorded or played back, and except for ATSC off the air, only 2-channel audio is available.
I took my laptop with me while I drove my mother back from Florida two months ago and tried the unit out in the Boston airport and at several stops along the way. The included small antenna was just adequate for picking up FM and TV stations in cities, but like most rabbit ears of years ago, didn't do well in the country. My laptop, which is about four years old, couldn't quite keep up with the high definition off the air signal information, stuttering at times, but that was not the fault of the Stick. I even tried it at my mother's house with her regular cable service, and got crystal clear (for cable) pictures. So the big advantages of the unit over a computer video card are its portability, usage with laptops, ability to pick up and playback FM and especially its ability to record high definition off the air ATSC television in 1080I or 720P. At its list price of it's a relative steal over computer cards and I've found it for as little as $49.99 on Froogle.