the next step in home audio?

 Still cold from the UPS truck the Apple HomePod woke up when I plugged it in and asked my iPhone for a dance.  They spun about and chatted in their local network for a minute or two before Siri introduced herself.  It was completely unexpected surprise from a great friend who  shares the love of music.  A day into the journey I have a few thoughts.

 

I'm a poor musician, but find it an important part of my life.  Grad school was at Stony Brook.  Besides an excellent physics department one of my reasons for doing grad school at Stony Brook was its proximity to music in  New York City..  That wasn't quite enough, so two of us founded a concert series at the university that thrives to this day.  At Bell Labs it became apparent that music might be a significant driver for Internet use and I found myself walking several paths.  One was sound field reconstruction.

 

Sound field reconstruction is just the fancy way of  recreating the sound where it was recorded or engineered in your home.  In theory you record the acoustic signatures of the recording studio and your living room and create a mathematical operation that makes your living room sound like the recording space.  In practice it's approximately hard.  Sound waves are fairly large and get reflected, absorbed and transmitted by and through everything in your room.  Making matters worse the sound field at different spots in the room is usually very different and things in the room move between and during listening sessions.  We made serious progress, but it took exotic microphone and speaker arrays as well as state of the art (for the time) computing to make it sort of work.,

 

One detail is centrally important.  Imagine sitting before a simple speaker cone.  Most of the sound comes straight at you with the volume falling off as you get away from the speaker's central axis.  Speakers have very characteristic patterns showing how loud they are depending on the angle you're sitting at as well as the frequency of the sound they're producing.  If you have two stereo speakers there is usually a sweet spot where the sound reproduction is optimal.  In this area the sound field can be fairly good and you can close your eyes and visualize where the musicians are.

 

Imagine an array of speakers, each with its own amplifier, all controlled by a computer, you can control the phase and amplitude (loudness) of each speaker.  The waves they send out interfere with each other as they expand outwards.   By controlling the phase and loudness (amplitude) of each speaker you can make them interfere in such a way that they create a new wave that can be aimed.  The little animation shows an array of four speakers in a row, but it can be any number and they don't have to be in a line.  The HomePod uses seven small speakers arranged in a ring.  

(you may have to click on the animation to start it)

 

The HomePod also has a ring shaped array of six microphones.  They listen to the room (sample it) at a fairly high rate and decide what parts of the music, from its stereo signature, need to go where and how it needs be modified to interact with the room and everything in it.  An Apple A8 processor, the same two billion transistor processor used in the iPhone 6 and 6 Plus, handles the computational chores.  This is much more power than we had back in the day.  Although I don't know exactly what they're working on, several people I know who are real experts at this have been at Apple for years.

 

 

The HomePod also has a computer controlled single woofer with its own amplifier mounted vertically to handle the low notes.  

 

I'll leave the specsmanship, mechanical and most of the UX discussion to others and just talk about what it sounded like.  I'm not golden eared, but rather a serious listener.   I focus on the music and let it take me where it pleases. 

 

I listened to works across several genres with the HomePod placed at about ear height in a small acoustically complex room.¹   For very small groups - soloists and piano quartets for example - the sound stage was excellent ..  about as good as my stereo pair of conventional speakers (about $3,000 in speakers).  The HomePod didn't match the reference speakers when I was sitting at the sweet spot, but was better when I moved around the room.  That is astounding. 

 

It was creating stereo -a  term has nothing to do with a pair of anything, but rather three dimensional.  Moving  beams of audio around it was painting a sound field in my living room. 

 

As I listened to larger ensembles I found a less accurate sound field.  That said it was still comparable to my reference pair when I was away from  my very small sweet spot - its effective sweet spot was larger.   Note for some pieces of music a good $500 pair of speakers would do a better job if properly installed, but  would love to see what a pair of HomePods placed about two meters apart would do.  Apple has promised the feature will be available later this year.  I've already earmarked the funds for immediately buying a second unit then.  I suspect a pair of HomePods will blow my reference pair away when it comes to sound stage placement.   That will be even more true for those who haven't carefully adjusted their current speakers with test recordings and a spectrum analyzer. 

 

You can control it from an iPhone, iPad or Mac, but Siri is the intended interface.  I've had poor luck with Siri on my iPhone, but here it works much better.  It's also much more robust to interference.  Microphones beamform too and it's clearly listening to you doing its own cocktail party trick.   That said it, and every other interface I've seen are just wrong when it comes to classical music.

 

Comparing it to the networked speakers from Amazon and Google is silly.  Their speakers are terrible and useful only as acoustic wallpaper you listen to in the background.  They're really microphones in your home listening to you assuming you agree to Google's  or Amazon's value proposition (I don't).  Privacy is vastly different - I'll go with Apple's differential privacy rather than Google's "you are the product" flavor.   But if music is secondary and you want a digital assistant with a speech interface, Google and Amazon are the ticket.  Apple is going after the other audio companies along with making its platform stickier in the process

 

I suspect the speaker will be like the Apple TV - fairly stable hardware with the bulk of improvements coming through software updates.   My list of UI and UX issues is growing, but I suspect this will become part of my life. 

 

And a final caveat - speakers involve personal taste.  YMMV

 __________

¹ I'm very familiar with these pieces.  With one exception  I've heard them live and I've even been involved in the recording process on two. 

Ecstacy  Anonymous 4 and Mike Marshall

Us  Regina Spektor 

Seven Swans Al Petteway

The Heart Asks for Pleasure First  Ahn Trio

Black Horse and the Cherry Tree   K.T. Turnstall

The Littlest Birds  The Be Good Tanyas

Submarines The Lumineers

Pipeline (electric and acoustic versions) The Duo Tones

An Spailpin Fanach Connie Dover

The Heroic Conditions of the Universe Pt 7 After the Storm Alexandre Desplat

Turn it Around Lucius

Jolene Mindy Smith's version

Vespro della Beate Vergine: Domine ad Adiuvandum a 6 Monteverdi

Shchedrik Kitka

Our Town Iris DeMent

Sun Will Set Zöe Keating

Don Giovanni Madamina, IL Catalogo and Questo Mozart  (sort of a sign of politics)

Canon a due Violincelli in D Major Gabrielli

Cello Sonata in D Major Op 69 Beethoven

Suite No 6 in D Major  JS Bach (Yo-Yo Ma)

   

Comments

[Neal E. Cammy]

What Apple has attempted to do is to remake the “hi fi” experience, which was the way we listened to music in the past. People have given up hi fidelity sound for convenience. Even if you wanted to play your music through a traditional “stereo system, you needed a big receiver and expensive speakers. If one or two Homepods can deliver better sound than $1000+ systems, with simpler setup, that’s a game changer. Apple is not competing with Amazon Echos, but with the Denon’s, Bose and Klipsch’s of the world.

[Joe Casanu]

Yours is the first I’ve read that has begun to explain why we need to rethink our common definition of “stereo,” e.g., 3D reference. Would you care to elaborate more? That’s a major evolution. Thanks

[Joseph]

The great thing about it is spatial awareness, the sweet spot follows you, not the other way around, which just isn’t possible with traditional speakers. Just a small correction A8 comes from the iPhone 6.

[Glenn C]

Nice piece. Thank you for posting. However - sorry - pet peeve: it's->its needs to be corrected in at least four places.

[Bob Varipapa]

Would you share the playlist on Apple Music?

[steve crandall]

On a playlist.. very little of it is from Apple Music.. mostly CDs, DAT tapes and lossless files.

[Richard Koo]

Your list of music is great. Yours and mine overlap quite a bit. The only thing I would add is that home pod does jazz very well. The first thing I played on the home pod is the Apple Jazz station. It was astounding. Jazz trio sounds so intimate, detailed and alive. I was amazed. I also found that newer recordings tend to sound better than older ones. Anything recorded after 2000 in my library sounds great. It does not mean recordings from before 2000 don't sound good; I just have not tried many of them. I thought my Beatles were a bit dull.

[AlG]

Do you find the lack of treble and bass adjustments to be a problem? For many who use hearing aids or are somewhat hard of hearing the normal balance is off and needs adjustment in many situations.

[steve crandall]

|Do you find the lack of treble and bass adjustments to be a problem? For many who use hearing aids or are somewhat hard of hearing the |normal balance is off and needs adjustment in many situations.

I do. Hopefully they'll add that in a future software release. As noted I find they're too bass heavy for the type of music I listen to. It would be nice if they opened it up for IOS developers. Most people could get by with three adjustments, but someone more critical or someone with hearing loss would need finer gradations.

[Dom Ruiz]

What do you mean by the interface being wrong for classical music? I'm not sure I follow what the genre of the music has to do with Siri. Do you mean HomePod has more trouble hearing you when classical music is playing, as opposed to other genres of music?

[steve crandall]

|What do you mean by the interface being wrong for classical music? I'm not sure I follow what the genre of the music has to do with Siri. Do |you mean HomePod has more trouble hearing you when classical music is playing, as opposed to other genres of music?

The scheme for identifying classical pieces is complex. iTunes and the Siri interface fails. There are often many performances by many artists of a particular piece. The piece itself is sometimes identified by key and often by a numbering scheme of a cataloger or by opus number. Sometimes an artist may have recorded a particular piece many times in his/her career. Pieces usually have several movements and are played as a whole rather than by movement. I suspect the database for iTunes is inflexible. If it is flexible Apple should hire a musicologist and do something useful. The same for others.

[Robert]

The handling of classical music catalogs has always been an issue. Perhaps a flaw with the tag format every music app uses. Plex is a bit fungible but still is it a performer, an organization, a composer or the composition, OR is it the particular recording!

Thanks for your review.