10 Secrets to Better Digital Audio
Since the first digital music became available on CDs some 30 years ago, it has never matched musicality and natural sound quality of vinyl. This struggle continues with the new generation of high‐resolution digital music which is often disappointing. Fortunately, as hardware and software technology is improving and as we are learning how to implement it, great improvements are possible. Here are 10 secrets we have learned that can be easily implemented in your digital music systems. As always in audio – trust your ears and adopt as many of these secrets as your ears tell you to.
- A short signal path … almost always leads to a better sound; is one of the golden rules in audio. At the Rocky Mountain Audio Fest show Teresonic assembled a digital system with a very short signal path consisting of speakers and only three (3) electronic components. In addition, each of the components was optimized to internally provide the shortest signal path possible. For example, music was played from a music server that was using the new generation processor that provides on‐chip conversion to SPDIF to eliminate the need for USB2SPDIF conversion and USB cables and connectors. The amplifier was an integrated tube amp with ultra‐short signal path and no capacitors in the signal path, and single‐driver speakers used no crossovers. Such a short signal path produced stunning results: “…one of the top four rooms at the show.”, “The sound was extremely transparent and beautiful.” – Stereophile, read more…
- Digital cables are more demanding … than traditional analog interconnects. Digital signals consisting of 1’s and 0’s are delivered as a series of rapid transitions in voltage and requires cables that can propagate very high frequencies to avoid ‘jitter’ and other distortions. That means high bandwidth and Teresonic digital cables are designed and manufactured to allow propagation of signals in the MHz range. Actually, all Teresonic digital cables are designed and tested at over 200 MHz, way beyond even highest resolution music files. The other issue with digital cables is their length due to signal reflections. Hence all Teresonic digital cables are at least 1.5m in length to minimize potential reflections of digital signals (“return loss”). While some of the best DAC (Digital‐to‐Analog Converter) manufacturers recommend at least 1.5m or longer digital cables, many users and cable manufacturers don’t understand this undesirable effect that impacts quality of digital signals.
- DAC inputs and outputs… Always use balanced inputs and outputs if your DAC, your music source, and your amp have them. If not, make sure they are on the list of requirements when you upgrade your equipment next time. There are many reasons to use (true) balanced inputs and outputs including up to 5X higher signal levels they carry compared to single‐ended connections. In addition, separation of minus (‐) signal wire and ground wire in balanced connections prevents ‘digital noise’ from spreading throughout the system. Most good DACs provide balanced (XLR) outputs to connect to your amplifier. Balanced inputs (AES) aren’t yet as common but are equally, if not more important than balanced outputs.
- WAV is the format of choice! This is another controversial issue as proponents of lossless formats such as FLAC believe it matches qualities of native WAV format while offering better tagging. In hundreds of experiments we made we always preferred the sound of WAV format and it is now used exclusively in our equipment demonstrations. Like many things in audio let your ears decide and try side by side comparisons. Some audiophiles even report sound improvements when they convert existing FLAC files to WAV and play them as WAV. Again, rip your CDs files in WAV – as they are already recorded on the CD as WAV. Yes, WAV will take more space but some day in the future you will be glad you did. Any ‘lossy’ formats such as MP3 maybe good enough to listen to while exercising but simply have no place in high end audio.
- USB vs S/PDIF… Here is another controversy as many ‘experts’ will proclaim the superiority of USB solutions. There are music servers such as Baetis Audio that proved SPDIF digital audio done right sounds even better than USB done right! In addition, lots of equipment like CD/DVD players output S/PDIF only, but only computers output USB. Most DACs use USB to S/PDIF converters and feed the converted digital signal to the DAC chip. That means that the USB input module is just an extra part to the same DAC unit which costs more money than the DAC without that module. The bottom line: use S/PDIF ‐ if done right, and you can save money and get a better sound. For details how to choose a digital cable see Teresonic digital cables.
- RIP quality Ripping CDs is a good idea even if you are not up‐sampling ripped files. Avoiding CD player electrical and mechanical components and their associated issues, and streaming files directly to a DAC leads to wonderful sound improvements. We now rip all of our CDs as soon as they arrive and keep physical CDs as a backup only. Of course, it’s critical to use high quality ripping software such as dBpowerAmp since differences between various ripping software packages can be significant.
- Choose your Digital Audio Player wisely! One of the most critical components in digital audio are music ‘players’ – software that interprets your music files and sends them to the DAC. The best players introduce minimal ‐ or no DSP (Digital Signal Processing), and avoid most of operating system’s ‘interventions’ so that music files arrive to the DAC intact. Players are platform dependent (Mac or Windows) and there are some good products available. For example, JRiver for Windows & Mac provides an excellent player as well as music organization capabilities.
- High resolution files vs CD quality… Not all HR (High Resolution) digital music is created equal! Don’t assume HR files will sound better than your ripped CD files (44 kHz/16 bit) just because they are HR (96 kHz/24 bit or 192 kHz/24 bit). Actually, many CD quality music files will sound better than many HR files. It all goes back to how the original recordings are made and processed, and how HR files are made. Should ripped CD quality files be ‘up‐sampled’ from 44 kHz/16 to 96 or 192 kHz? Not necessarily, but up‐sampling can improve sound quality if done right (see the up‐sampling secret).
- Up‐sampling? Offline up‐sampling of music files always sounds better than online up‐sampling – a feature in most high end DACs! Turn off the up‐sampling feature in your DAC and do up‐sampling offline. Pro tools such as iZotope do a fantastic up‐sampling job although they aren’t cheap. Again, rip your files in the original WAV format and up‐sample them in the same WAV format.
- Bypass digital volume control The digital volume control provided on many DACs introduces additional digital signal processing that can degrade sound quality. Fortunately, most good DACs provide a way to bypass that function. Just say no to digital volume control and use the volume control on your amplifier – even if you can’t do it remotely J Yes, there are DACs such as Berkeley Audio Reference that provide good volume control – if you can afford it.