Do you “Stream” your music (eg: iTunes Music) or Do you use your CD collection - or even treasured vinyl records? How the Mentor’s role is changing!! Very few of us teach the basics of “what is a computer”; “what is a keyboard”, or “what is a mouse”. We are increasingly being drawn into solving problems with pairing the smartphone with the car, or why the Netflix subscription will not Stream to the TV in the bedroom? This week I had a lengthy debate with an Audiophile friend about moving from my old CD collection to Apple iTunes. I would now be hard pressed to find anything at home on which to play any of my old CDs, and you may note that many newer cars no longer include a CD player. Such a thought is an anathema to the CD aficionado, although their reasonings are becoming increasingly difficult to defend. Or are they?? The vinyl record enthusiast, on the other hand, has always been on firm ground as the technical format of the sound has been largely preserved from the lungs of the singer to the speakers of your historically expensive Marantz Stereo System. (Note: since September 2020, Vinyl record sales have exceeded the value of CD sales) While we will delve into the future of Music Streaming vs the CD collection, lets first revise “Audio Fundamentals 101”. We humans make sounds by vibrating our vocal cords anything from 20 times per second, and up to 20,000 times per second (where you might be more whistling than singing). The usable voice frequency band ranges from approximately 300 to 3400 cycles per second, (commonly written as “Hz”.) by example, Middle C is 440Hz, and your Smoke Alarm is normally 3,100Hz. This sound is heard or transmitted by creating physical waves in the air - the louder the sound the higher the amplitude of wave, and the higher the pitch, the closer together these waves become, see below: The momentum to change this Analogue Wave Form into a Digital Signal can be attributed, largely, to the increasing demand to transfer movies from studios and production houses to TV stations, and between TV stations via the available telecommunications services such as phone lines. Such interchanges required very high phone line capacity, which was firstly expensive and secondly any noise introduced along the way impacted on the quality of the signal received. ie remember the old crackly AM radio or snow in TV pictures? Around 1988, a group of experts from the movie and telecommunications industries came together under the auspices of the International Organisation of Standards (ISO) and the International Electrotechnical Committee (IEC). Their task was to develop internationally agreed standards by which videos (including the Audio) could be digitally coded and transmitted. This group called itself the Moving Picture Experts Group, and their acronym MPEG became embedded in our daily language. (Along with a parallel group called the Joint Photography Experts Group, again with a familiar acronym) In brief, the Moving Picture Experts Group agreed on a standard to digitally encode audio files by sampling the analogue waveform (as shown in red in the picture above) by taking samples of the waveform at 44,100 times per second, and using 16 bits (0s or 1s) to define the properties of each sample point, thus resulting in the audio CD fidelity standard commonly expressed as 16 bit/44Khz, or simply 16/44 format. This 16/44 CD sample rate was also used for downloads of music files, so returning to the start of this story, the end result of a CD vs iTunes, Amazon or Spotify should have been the same? Well not exactly - in the early days of the internet (remember 128Kb ADSL?), the internet had insufficient capacity to listen to encoded audio, forget about video, so the Moving Picture Experts Group developed a number of layers for compressing encoded audio and video. For Audio it was “Layer 3” lovingly known as MP3. Similarly, Video was Layer 4 - so guess the common name for video files and players? The compressed coding means that the CD quality of 16/44 coding has information that is lost in the compression for MP3 files and players, so the CD Audiophile’s quality arguments of that time were valid. Move forward to the last 10 years. Internet speeds in the millions of bits per second (Mbps) became the norm, storage in the thousands of millions of bits (Gb) became the base model. This allowed the music streaming services such as Spotify, Amazon and Apple to develop higher fidelity streaming. While CDs have remained with the 16/44 sample rates, online music has gone to 24 bit/192 kHz, or even 32/192, meaning that the digitised waveform would more accurately replicate the original analogue wave: see simplified comparison below. Today, the CD argument is losing a bit of ground, but nothing is ever that simple. The streaming services have achieved high resolution rates by developing Advanced Audio (en) Coding/Codecs (AAC). To some degree each supplier’s AAC may not be completely compatible with the HiFi encoded music from another library, and even though you may be able to listen to iTunes music on a Google player, some of the digital information, particularly the proprietary higher fidelity detail will be lost. Major online music libraries are going further with their own proprietary (non standard) versions of “lossless” codecs, such as Apple’s Lossless Audio Codec (ALAC). While there may be no digitised information lost by compression, they are not necessarily Hi Fidelity, (a song might still be 16/44, but not compressed) and they almost certainly will not preserve lossless quality between brands. The other downside is that music files that exceed the 16/44 MP3 or CD standard are only by subscription. So - does today’s streamed music sound as good or better than CDs from your collection? Maybe!!

• IF you pay for your music via subscription
• IF you have a player compatible with your streamed music, and
• IF you use a sound system and speakers which support your streamed formats, ie an ALAC coded track will sound great on an Apple HomePod!

And sorry - if you are going to stream HiFi music, you will need to throw away that precious $5,000 sound system you justified as a 25th wedding anniversary present to yourself, and the $5,000 B&O speakers? They must go too! Some newer expensive third party sound systems do support digitised music that exceeds the CD/MP3 16/44 standard, so read the specifications carefully before purchase. On second thoughts, maybe it is easier to keep using your CDs? Steve Dixon