This is an update on my experiments with surround sound at home for playback of serious music: I've set up a music listening room in the basement of my terraced Victorian house in Hammersmith, West London.

Sound system for serious music

Digital technology now gives us the possibility of very high quality music at home, however this is frustrated by domestic considerations. I don't want to make my lounge so that I socialise in an environment like a studio control room. The walls here are thin and I don't want to inflict my music on my neighbours nor do I want to hear theirs whilst I am listening to mine. And I want to listen away from noise of the big metal birds on their flight path down to Heathrow, not to mention the road and pedestrian traffic outside my front door.

Headphones

The obvious solution has been headphones: these work well for sitting down and listening to classical music, including following through with a printed score. I've been using Sennheiser HD25 II, which are closed-back and give substantial isolation from ambient noise and so are popular with location sound recordists.

I moved on from HD25 to Sennheiser HD650; these are even cleaner but are open-back so offer very little isolation. It's worse than that because listening intently emphasises sounds from the real world simply because one is listening actively.

My problem with headphones is not the cable but precisely because the sound is so intense and the transducers so analytical that it is often quite difficult to "suspend disbelief" and simply listen to the music: the craft of making a sound recording of a performance of music becomes too apparent.

I should explain that my taste in music which I am happy to sit down and listen to goes all the way from Choral Evensong through to Glastonbury Music Festival: Alfred Brendel though to Clarence Clemons. It's fine to listen to Lady Gaga or Marc Almond on headphones on a plane or train but it's not really on at home.

So the world of headphones, although relatively inexpensive and clearly of "reference" quality, does not provide the complete solution.

Quadraphonics & Ambisonics

There was lots of talk of Quadraphonics and Ambisonics back in the seventies: the BBC started transmitting using UHJ and I (among a few others) read the stuff in Wireless World and Hi-Fi News magazines, bought and assembled the kits and tried listing to music with four or six speakers. In my case, I bought at set of Rogers LS3/5A bookshelf speakers and built a sub-woofer and played around with crossovers.

It didn't really work out well enough, despite buying the records – "Dark Side of the Moon" in QS and many records of Chopin piano music in UHJ from Nimbus - and enjoying a treats like the BBC relay of a Genesis concert from the 1978 Knebworth festival. The eventual solution has been headphones plus a stereo pair of massive Kef 107 speakers that are nicely smooth but are rarely allowed to play loud enough to do justice to the music.

2012

Onwards thirty years: now we have had CDs at home for getting on for a generation; personally, I've moved from a PCM-F1 recording to Betamax on to hard disc recording with CuBase, Audition or Wavelab. And commercially we have SACD, DVD and the BBC's Radio 3 available in 320kbps, 44.1kHz AAC format, a massive improvement on DAB and FM/VHF. So time to look again at home music reproduction.

The LS3/5A speakers now fetch amazing prices (>£1250) on eBay despite the speaker units not being a fashionable dome tweeter and the mid-range not being formed of the latest wünder material. Listening to them critically, and remembering the classical concerts which I go to regularly, the LS3/5A are not as clean as even the Kef 107 from the eighties and nothing like as clean as the Sennheiser HD650 headphones.

I find the LS3/5A have a bit of bass boom, the sound gets muddy quite quickly with a bit of loudness and there is a degree of beaming from the tweeters. That's being critical, they're small, "easy" to listen to in the sense it isn't a brash, pushy sort of sound. Also, I have them here and they are in good condition. And surely they can't be that bad if people on eBay will pay over £1000 for a pair!

Digital end-to-end

On the technology front, amplifiers have moved on too. I've been relying on a Quad 606 for years and it's still driving the Kef 107's just fine. But thinking of a surround system then there's a need for certainly four matched amplifiers (for 4.1), probably five (for 5.1) and maybe seven (for 7.1) main amplifiers.

And it's not just the amplifiers, there's the decoding of the digital sound stream with a digital to analogue converter. It seems that adding an SACD player in to an existing system can produce high frequency problems, especially using an analogue signal connectyion and if the earthing is not consistent. Fortunately it's now feasible to maintain digital right through to the amplifier power driver stage, effectively the Class D amplifier becomes part of the analogue to digital conversion, although the manufacturers don't describe it like that. Such boxes are described as AV receivers and are intended as the centrepiece of a home cinema installation.

HDMI is the interface that maintains digital from box to box, between optical disc player and AV receiver. Making the digital signal available outside the optical box isn't contentious for DVD or CD so there are optical and SPDIF interfaces available, however, due to anti-piracy considerations, it is only recently that the high resolution formats like SACD and BluRay have been available in digital format outside the optical player. In practice this means checking the manufacturer assures that the HDMI connection will work for SACD.

And a sub-woofer is needed to help give some low frequency depth to the sound from the small LS3/5A boxes and clean up their tendency to muddiness when loud.

Ambisonics vs Surround Sound

As a simplification, Ambisonics is intending to reconstruct acoustic wavefronts to recreate the sound field at the recording venue whereas formats like Dolby Pro Logic II and DTS have been developed from the perspective of surround sound for movies. Pro Logic II seems to make a nice sound but it can become tiring for music as there is a degree of steering, meaning that the apparent location of sounds is emphasised by the decoder. Some programme material turns out very surround if decoded by Pro Logic II although not advertised as such, e.g. the New Year's Day concert relay from Vienna.

Home cinema vs Music listening

Ambisonics requires at least four speakers (preferably six) and the movie 5.1 surround formats include a front centre-speaker. There is some material around using higher order Ambisonics but these give height information so seem more for dramas and games than for music reproduction, though never say never. Anyhow I really don't have space or finance for around sixteen speakers plus the unforgettably-named ButtKicker® infrabass.

Shopping List

My shopping list was KEF Kube 2 Subwoofer, Yamaha RXA1010 Aventage AV Receiver and Yamaha BD-A1010 3D Blu-ray Player, plus some speaker stands

Room acoustics

The electronics is relatively straightforward; all of the above are available commercially so it was a matter of sifting through a lot of spec sheets and getting good pricing. Where to install the electronics and how it would sound is where there is still black art.
My basement is relatively small (1.5 x 2.5x 6 m, WxHxL); the previous sound system was a couple of tiny aluminium speakers from Tandy, about 15 x 7 x 7 cm. This had proved acceptable when the cellar was used for DIY so the first stage was to try listening to music using them.

Work needed to be done to make the room comfortable, to make a basement out of a cellar, but without endangering the ventilation or damp treatments. This wasn't too difficult and also has reduced the noise penetrating from outside.
The walls are painted brickwork or waterproof render, the floor is rubber tiling and the ceiling the undersides of floorboards and joists: it was not a surprise that the untreated room sound was boomy bass with unfocussed mid/high frequencies. It was promising that the near-field sound worked failrly well, i.e. making an equilateral triangle with my head and the speakers.

Encouraged, I looked for a comfortable chair; the access is too narrow for a standard armchair but there are self-assembly chairs available for situations like this, canal boats etc.

The usual way to treat room acoustics is to diffuse and/or dampen the reflections that cause standing waves, this typically involves adding panels of dense foam to walls and wedges to corners. Adding a relatively large chair to the middle of the room, leaving just a squeeze walkway either side, has achieved much the same effect: the bass has cleaned up and the Kef Kube 2 Subwoofer has enough power to drive it.

Aiming the sub-woofer driver and passive driver front/back helped minimise exciting of room nodes and so reduced the room boom further. A further improvement came from a large piece of heavy carpet underlay covering half of one end-wall, this acts as a suspended-membrane absorber.

Stereo imaging was still a bit diffuse, which I thought was primarily because the speakers are very close to brick wall. It's not difficult to imagine the wall as a mirror. It has not been a problem to reduce these early reflections with a couple of heavy towels suspended in the right place, so a treatment without drilling or sticking material to the damp treatments and brickwork.

Yamaha's YPAO automatic setup has worked fine to set up the crossover to the sub-woofer and the levels and delays to the main speakers.

Music

A tekkie investigation is fine but the point is to enjoy the music: does the room work to enjoy music. The answer is definitely "Yes": the chair is comfortable, the noise penetrating from outside is much better than in my lounge and when I emerge from the basement after a session it is striking how the noise increases from outside. There isn't a problem with playing music loud enough to enjoy: Karajan's recording of Richard Strauss's Alpine Symphonie was a good test for that. Non-classical music works fine too.

The detail and stereo image isn't quite as good in comparison with the Sennheiser HD650 headphones but the balance is similar and the room is not unpleasantly dead acoustically.

SACD

I wanted to benefit from the full quality of SACD recordings, many of them are 24 bit, 96 kHz sampling with four discrete channels of surround sound. Another "Yes": at last surround sound works well at home! Not just for the obvious single well-placed mic recordings like church organ music but also for orchestral recordings. Even the venerable LS3/5A drivers working to my fifty year-old ears show a clear difference compared to 16 bit, 44.1kHz CD quality.

It's more a smoothness and sheen and sparkle rather than any particular brilliance. And it's still not the same as the warmth and detail and depth that I can hear at a live concert in a seat that's not-necessarily the "best seat in the house". There really is a much greater sense of the actual acoustic, whether the vacuous neutrality of Orchestra Hall, Chicago or a chilly church in Leipzig.

There are a few pieces which have been worthwhile buying again. The Who's rock opera "Tommy" has been reissued in a surround sound remix credited to Pete Townsend. The sound has that characteristic warm bloom of a recording remixed direct from the original one-inch eight track without Dolby noise reduction: each track as wide as a stereo track on ¼" tape. The mix is very much a surround mix placing the listener in the middle of the music, and with a just a couple of surprise spot effects.

Another good buy has been Pink Floyd's "Dark Side of the Moon". That was a sixteen track and whilst the remix doesn't have the bloom of "Tommy" it's much cleaner than I remember the seventies QS mix. Now the never-ending discussion on whether you prefer a Shure V15 pickup cartridge to an Ortofon MC is over!

Upscaling stereo to surround

But the majority of my record collection is stereo and likely to stay that way. The original Ambisonic decoders of Michael Gerzon's time in the seventies and eighties included an up-scaling feature from stereo to multi-channel. Yamaha provide an equivalent facility with the DTS Neo 6 decoder, there are cinema and music modes. As with Pro Logic II, the music option seems more relaxed.

It took a while to "learn" to hear stereo on loudspeakers and it's similarly taken me a while to learn to like what the Neo 6 decoder is doing. It's a bit like first drinking beer as a teenager, Real Ale is not a divine nectar at first taste but in time some get addicted, some like it and some never take to it. I think it's the same with Neo 6.

Some two-channel recordings are, intriguingly, part surround and part straight stereo. Some broadcasts of Choral Evensong play convincingly in Pro Logic II with the singers definitely front only. It could be coincidence with the decoder grabbing the ambience and spreading around the rear speakers but it is either there and convincing or it is not. It's nice when it's there and it works.

Now, having educated my ear and brain, I am finding that, in most cases, switching back to straight stereo looses inner detail, the sound stage recedes and my involvement with the recording suffers. So Neo 6 stays as my default selection for straight stereo.

UHJ

There is a considerable body of music recorded with two channel UHJ Ambisonic matrix encoding, some was documented as UHJ on first release but the UHJ labelling has disappeared on re-release though the sound seems unchanged similar, at least on the couple of examples I have checked. Most of my CDs from Nimbus are marked as UHJ encoded.

Unfortunately there doesn't seem to be a cost-effective means of correctly decoding UHJ in a domestic setting apart from software plug-ins or some high-end Naim Audio hardware. I'm rueing the day that I discarded my build of the Integrex kit of the design published in Wireless World in 1977!

My experience is that neither the DTS Neo 6 nor the Dolby Pro Logic decoders make good work of the UHJ signal: most of the image homes to about three-quarters front-left. So I've not found a better way to listen to UHJ recordings than in compatible stereo.


Next steps

So far no screen: I've set up a room to listen to music seriously not a home cinema. A screen is necessary to understand fully the AV receiver and I am using my laptop to access .wav files of my previous PCM-F1 recordings but so far no home cinema screen.

The question becomes "How big a screen?" Big enough for the movie experience? But DVDs of opera and relays of orchestral concerts tend to go in much closer than you can see from an ordinary audience seat position and I don't think these work played to a large screen. It's nice to have video of the concert hall or festival but usually with music the visuals are not the main event. There are also the conflicts of picture against sound, including wanton crossing of the various "lines" in visual grammar. Shows like Take That's "Progress Live" tour or Queen at Wembley in 1986 are different though.

For the sound, well maybe my credit card would take a bill for four new speakers but I'm not convinced it would be really worthwhile. The differences in the performances and recording techniques are usually far more significant. Better to spend the money on tickets to live concerts. And some damping that is more pretty than a couple of towels!

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