Video on demand technology for your home – Part 2

This series of two articles looks at what you might need to get the best possible experience of watching concerts or opera from streaming services like Met Opera on Demand or the Berliner Philharmoniker Digital Concert Hall. The first article looked at internet and video: this article concentrates on audio and on putting the whole system together.

The range of audio Hi Fi gear available in the world is gigantic and it would be crazy to try to tackle it all. So I'm not going to give you a kit list: rather, I'm going to explain the types of equipment available and what you might look for when making your choice. Where I mention a specific product, it's to show an example of the type rather than to give a specific recommendation: I haven't done any serious comparative evaluation of competing products.

To keep the article manageable, I'm going to write as if you're buying from new. In reality, I realise that top quality audio gear is expensive, so your choice may well be overwhelmingly conditioned by the investment you've already made.

Headphones

The caveats aside, let's start with the cheapest and easiest thing you can do: buy a decent pair of headphones, plug them into your tablet or laptop, and curl up on your sofa. You can get excellent quality without spending a fortune: even respected companies with recording studio heritage like Audio Technica, Sennheiser, AKG and Beyer Dynamic have offerings that will leave you change out of $100. Here are some of the things to look out for:

• Are they comfortable to wear? If you're going to watch four hours of Wagner opera, you want to know that your ears aren't going to overheat or feel squashed.

• Do you like the sound? Beware of headphones optimised for rock or electronic music which have been designed to be bright and exciting or to give extra bass boost: you may find them hard on the ears after an hour's classical music. There's very little advice I can give here other than to suggest that you go to a real shop who will let you try a pair - and I'm fully aware of how difficult that may be.

• Open, closed or in-ear? Each has its pros and cons: In-ear phones are easier to carry around and have low sound leakage both in and out, but you may or may not find them comfortable. Open over-ear headphones are likely to be the most comfortable but are likely to leak sound to other people in the room (which may or may not matter to you). Closed over-ear phones can get hot.

Whatever your choice of headphone, if you find that the results aren't loud enough (or that the quality degrades when the music is loud), there are a variety of headphone amplifiers on the market. You can also buy splitter cables to allow two people to listen at the same time.

Your TV

Headphones aren't quite the cheapest option: there's always the choice of listening to the audio on the loudspeakers built in to your TV. For the overwhelming majority of TVs, I strongly recommend that you do NOT do this: the quality of virtually all TV loudspeakers is very poor by audiophile standards. More expensive TVs have more powerful speakers (or you can buy add-on "sound bars"), but these are generally designed to make movies sound bigger, brighter and bolder - design criteria which don't sit well with the high fidelity to the original sound that is needed for classical music.

The signal chain

The chances are, therefore, that you're going to be putting your audio through your Hi Fi system. But what kind of Hi Fi - and if you have one already, should you buy any extra components? To help you make an informed decision, here is a diagram of the typical signal chain - everything the sound will go through.

The functions in the white boxes will happen in just about every system. But there are dozens of different ways of packaging them into different boxes: the diagram above just shows the most common one.

The key thing to understand is that the two most likely places for you to lose quality are the ones marked in red: the DACs (which I'll explain below) and the loudspeakers. You can lose quality anywhere, of course - crossovers, cables, even the humble volume control can introduce distortion - but the loudspeakers and DACs are the prime suspects.

Loudspeakers

I can't emphasise it enough: if you're not sure where to put your money, put it into the loudspeakers. It's the single area that will make most difference to your sound. Because the sound of a loudspeaker is considerably subjective, this is also the product area which provokes the greatest amount of religious argument between the followers of this or other manufacturer. Kef, Tannoy, B&W and Monitor Audio are just some of the many names you'll find with good Hi Fi credentials.

First, make sure that the loudspeakers you're proposing to buy are loud enough for your room without being pushed to distortion. Next, as with headphones, beware of loudspeakers designed to make rock music sound bigger and bolder. If the marketing blurb has words like "vibrant" or "dynamic", there's a fair chance that the sound will be coloured in a way that you may not appreciate when listening to classical music.

But then, it's time to start listening. Don't rely on the shop's demo tracks: use CDs of a variety of music that you know really, really well, so that you can spot any nuances.

For the technical 

There are two fundamental categories of loudspeaker to choose from: passive and active.

Most domestic Hi Fi speakers are passive; in other words, the power amplifier is in a separate box to which the speaker is connected by a cable capable of taking moderately large current. A passive speaker doesn't need its own mains connection.

In contrast, most loudspeakers used by recording studio professionals are active; in other words, the power amplifiers (often more than one of them) are mounted directly inside the speaker cabinet, removing the need for high quality loudspeaker cables (but meaning that you need to connect the loudspeaker to the mains). There are big design advantages to this approach when trying to get the maximum fidelity at the lowest component cost.

My personal preference is for active loudspeakers: I'm a particular fan of speakers made by Finnish company Genelec. But I realise this isn't for everyone. For a start, running mains to every loudspeaker can be a pain and, ironically, pre-amplifiers suitable for connecting to active loudspeakers are often much more expensive than a decent integrated amplifier.

Remember: loudspeakers are subjective things. When you make your choice, don't listen to me: listen to the loudspeaker.

Digital to Analogue Converters

The DACs are the electronic circuits that take the sequence of numbers streamed from the Internet (or from your CD/DVD player) and converts it to an electronic signal. You may not be aware of DACs as a separate entity, because they are always built into computers, CD players, phones, etc. The problem is that the DACs built into computers/tablets/phones are generally of poor quality. DACs in CD and DVD players are likely to be better, but that's by no means certain.

Most sound sources give you one or more ways to bypass a poor quality DAC. CD players, DVD players, TVs, set-top boxes and AppleTV provide digital audio output using an optical link; you can buy an adequate DAC for under $100, or spend hundreds or even thousands on really excellent DACs.

If you're starting from a computer with a USB port, you can buy a USB audio interface of the sort used by musicians to record their performances. Again, there are adequate units available for under $100, and you can get quality likely to satisfy most listeners at under $300.

You may have DACs built into your amplifier. This is especially likely if you are using multi-channel audio for surround sound (see below), but there are also stereo integrated amplifiers which contain DACs (the Marantz PM6005 is a mid-priced example).

Less probably, you may have good DACs built into a dedicated box built for networked audio streaming. The Naim Uniti all-in-one players are an example of this kind of product from a manufacturer with impeccable high end audiophile credentials (and pricing to match).

Putting it all together

We saw in the article about video that you have many choices as to what kind of equipment to use and how to connect everything up - let alone many choices of manufacturer and model. The same is true with audio - different products package things differently. Since the number of choices can be bewildering, here's a diagram of how a typical system might fit together. Use this as a starting point to understand what everything does, and then go and explore options for your particular needs and wants with your most trusted retailer.

The key choice that I've made here is to connect all the audio sources to the TV with HDMI cables and used the TV's digital output as the only feed to the audio system. This allows me to use a single separate DAC so that I can get the best quality. It also means that I have a much broader choice of amplifier/loudspeaker combinations to suit my budget.

The downside of this approach is that the TV has to be switched on for anything at all to work - even playing music from a CD. To solve this, take an additional audio output from your CD/DVD player and connect it to a spare input on the amplifier (as shown in the dotted line). 

Surround sound - do you need it?

So far, this article has assumed that you are using plain stereo sound. If, however, you watch a lot of movies, especially action movies, you may well want your audio to work in "surround sound": the domestic equivalent of cinema systems which try to provide a more immersive experience in which you are placed in the middle of the sound. In these systems, the stereo pair of "Left" and "Right" is augmented at the front by a "Centre" loudspeaker and also by a pair of left and right speakers at the rear. Finally, because action movies have serious low frequency sound effects, these five are augmented by a specialised speaker called a "subwoofer", whose job is to reproduce only very low frequencies. If you want your chest to vibrate when the helicopter is overhead or the earthquake is shaking the floor, you need a good subwoofer.

Collectively, this set of speakers is known by the moniker "5.1" (there's also a "7.1" with side loudspeakers, but that's less often used domestically). Fairly obviously, you have three times the number of loudspeakers, and if you're trying to keep to the same quality levels, you're going to paying in the region of three times the cost of your stereo setup.

If your primary purpose is to listen to classical music and opera, I'd personally stick to stereo. There are plenty of cheap 5.1 components around, but I wouldn't trust the quality and I would be worried that systems set up to sound good on speech and sound effects at a low price are unlikely to be well designed for classical music. If money is no object and you're not worried about the living room clutter of six loudspeakers, there are plenty of good products - but that's not going to apply to most people.

In any case, most of the streaming providers don't support 5.1 yet, and it's not their highest priority. As Alexander McWilliam from the Berliner Philharmoniker puts it: "a minority of my customers want surround sound. I can guarantee that 100% of them want interruption-free high quality audio."

Multi-room

If you want your audio to be played in more than one room, there are several products on the market that can help you. The market leader appears to be Sonos, who make a box called a "Connect" which you can place anywhere in your house and which will pick up audio from your network (Sonos also do a range of amplifiers and speakers with the Connect technology built in). The Connect box will take music from an analogue or digital input from your TV or Hi-fi, or will pick up music from a computer elsewhere on your home network.

In other words, you can use a pair of Sonos boxes to pick up audio from your streaming device and send it to another room. As an extra, you can also use it to pick up music from an iTunes library (or from other network sources such as Spotify or Amazon Cloud Player).

Remote control

With all these different boxes in your setup, you now have a living room full of remote controllers (my example would have five, and it's easy to go up from there). Various manufacturers sell products that can help you by providing a single device (and/or smartphone app) that will control all your gear.

This sounds appealing, but is a lot more difficult to set up successfully than one might like. I've not personally had much luck with devices which try to emulate your product's infrared stick controllers: most recently, I wasn't able to make Logitech's Harmony control my Samsung TV reliably. London installer Robert Taussig recommends the use of remote control systems such as Control 4 that talk to your gear over a hard-wired cable (usually RS-232); generally speaking, these are products to be installed by experts.

That's it folks!

When I started writing this pair of articles, I don't think I realised quite how many options were available. As a result, the articles have been much longer than I expected, while still only covering the subject at a very cursory level. Still, I hope it's been a useful overview, and if you want to know more or if you have experiences to share, please use the Disqus comment fields below.