Full house sound, wirelessly.

This piece gets a bit technical so hold on to your hat; however, it may be helpful for those experimenting with AirPlay routed to multiple speakers simultaneously.

Following up on yesterday’s column on using AirPlay with TuneIn radio on an iDevice, I rooted around and found another set of Logitech powered speakers languishing in the place the black beetles call home in the garage. These are the estimable Logitech Z4i with a powered bass and two satellites, making for excellent sound. Back when I used an iMac G5 and later the ill fated 24″ iMac which fried its GPU thanks to Apple’s crappy design, the satellites velcro’d nicely to the sides of the iMac’s monitor with the bass out of sight under the workspace. I had put them away in favor of smaller desktop speakers when I built the HackPro and had quite forgotten about them.

Well, as the shared Brother printer in the office is attached to an Airport Express (AEX) as a Bonjour printer, naturally I could not leave well enough alone, realizing that I could connect these powered Logitech speakers to the AEX for yet another sound output from any iDevice. A few moments of plugging things in and TuneIn Radio sound on my iPad was coming from these Logitechs.

Now how about full house sound? Well, I can’t see any place where AirPlay on an iDevice permits selection of multiple speakers, though I would bet dollars to doughnuts that this is only a matter of time. Maybe the iPad needs to be upgraded to the multi-core ARM A9 CPU before this becomes possible. However, firing up iTunes on the HackPro, where my extensive music library resides, I clicked on the AirPlay logo and this is what I saw:

AirPlay on iTunes and the HackPro.

Clicking on ‘Multiple Speakers’ I got this selection panel:

The multiple output panel in iTunes.

I checked off all the speakers and adjusted the volume but …. the sound keeps cutting out. Selecting just the HackPro’s speakers (“Computer”) all is fine, but select any other destination alone or in addition and the sound cuts out.

Going to Utilities->Audio MIDI Setup I adjusted the output settings to the least demanding, thus (2ch-24bit is the default):

Audio MIDI settings.

This reduced the cutting out but did not eliminate it, so I’m guessing there’s some glitch either in my wifi system (the HackPro where iTunes runs uses 2.4gHz 802-11n wifi as I cannot use pure 802-11n at 5gHz as I need the 802-11g mode for compatibility with my iPhone, and do not own the latest dual band Airport Extreme). All my sound files are in uncompressed format, meaning they are large, for maximum quality. MP3 is a poor, over-compressed format for sound fidelity. The file size doubtless is not helping matters.

For further diagnosis I went to the MacBook Air which uses 802-11n wireless, started iTunes and tried playing a track stored locally in iTunes on the MBA. Perfect. I could enable all remote speakers and all played fine with individual volume control available for each, suggesting that the lower speed of the 2.4gHz 802-11n on the HackPro may be a limiting factor. There are a lot of variables here so it could well be something else, but I expect I’ll get there through a process of elimination.

Getting ambitious, I next loaded the remote library on the MacBook Air from the HackPro, where iTunes->Advanced->Turn On Home Sharing is set to ‘On’. Well, the stuttering, while greatly reduced, was still there so clearly there is a bandwidth or speed issue with the HackPro which looks like it needs 802-11n. Meanwhile, I’ll just move my favorite tunes from the iTunes library on the HackPro to the one on the MacBook Air for those occasions when whole house sound is called for.

An encouraging experiment.

Update: A solution to the stuttering problem:

I put on the old thinking cap and took the resident Border Terrier for a walk. Always clears the mind, I find. I had never paid any attention to the sound technology in the HackPro where my iTunes library resides. All I need it to do is drive pokey desktop speakers for the usual mail sounds, etc. I do not listen to music through its speakers. Its 802.11g should be more than adequate for routing sound files, even if uncompressed. So could it be the Digital to Analog Converter in the HackPro that was choking? Well, I fired up that ancient old iMac with the 1.25 gHz IBM G4 CPU and a scant 1 gB of RAM which we have owned some ten years now. It’s mostly used for web surfing and is by far the most reliable Mac I have ever owned.

I reckoned that I would simply update iTunes on the iMac (which runs Leopard, the last version of OS X supported on the G3/4/5 CPUs) and then point iTunes to the library of music on the HackPro. While the iMac uses 802-11n it would still be no faster than 802-11g as the slowest component in the equation is the HackPro and it’s 802-11g. But, and here’s the key, I would be using the iMac’s DAC to convert the digital stream to analog sound and my bet was that even the ancient DAC in the iMac would be pretty good, given Apple’s focus on sound reproduction.

And this proved to be the case! I told the iMac to send sound to three speaker sets (Apple TV, Office and Dining Room) and it is playing perfectly for the past hour. If it does start to stutter, I’ll simply move the library of music to its internal hard drive, taking the HackPro’s poky wifi out of the equation, but so far it’s working fine. I suppose I could also place the iTunes files on an external hard drive connected to the iMac but Apple has said that it does not support external HDDs for use with AirPlay, so I’m not pushing that angle. It may work. It may not. What is tremendous is that not only does this ancient hardware support AirPlay with the latest iTunes download (congratulations, Apple!) but sports a decent DAC which is better than the PC-grade one in the HackPro.

This analysis seems to make sense. The old iMac is receiving a digital file and locally converting it to analog. The original approach had the HackPro sending out an analog file to the speakers and, I’m guessing, that’s larger than the pre-DAC-processed digital file. The speakers attached to the HackPro worked fine with no stuttering as they are hard wired, whereas the remote ones stuttered owing to their use of wifi for reception. So it’s either a slow DAC in the HackPro or the lack of 802-11n in that machine.

Another alternative is to retrofit the HackPro with a better DAC but, frankly, I can’t be bothered and so far my total investment in this project is one AEX for $88. That’s enough!

Bottom line? If you have an old G3/4/5 Mac in the home, consider making it a music server for use with AirPlay.

Meet my new old music server.

Second update:

After two hours of music play I would still get the occasional stutter. So I moved my iTunes library to the internal drive of the G4 iMac and loaded the library from there. After two further hours of listening there was no more stuttering.

…. when it comes to backing up.

A while back a fellow photographer mentioned to me that he used Apple’s Time Machine utility and found it a blessing when trying to recover previous layered images in Photoshop, after accidentally flattening the current version and losing all layers of the photograph on his working hard drive. Unlike regular backups which overwrite a file with the latest version, Time Machine maintains an intact catalog of all the versions of a file as it changes. So if you need to recover from destructive edits, it’s just the ticket.

I confess I pooh-poohed the idea as I don’t believe in any back-up that you cannot boot from, and while Time Machine back-ups can restore to drives which are bootable, you cannot boot from the Time Machine back-up itself.

But as this bit of wisdom came from a person whose views I respect, I slept on it and concluded there was a place for Time Machine in my back-up strategy which, troublingly, does not include an off site back-up. My MacPro has a 1tB boot drive and a like internal clone, to which an incremental bootable back-up is made every night using a scheduled task in Carbon Copy Cloner. But both boot and back-up drives reside in the same location inside the same Mac Pro. Catastrophe at that location would wipe me out. And cloud computing storage for large photo files is still a thing of the future, as broadband speeds in the US are simply too slow to upload and download large files.

So I messed about a bit with Time Machine and while I care little for all the glitz and fireworks of the interface, the application is easy to use and after the first backup (very slow – 4 hours to backup 400gB – with some performance drag on the Mac) incremental back-ups are fast. Because the volume of data being backed up incrementally is small, there’s no noticeable performance penalty. Time Machine saves hourly backups for the past 24 hours, daily backups for the past month, and weekly backups for everything older than a month until the HDD is full. After that, it’s first-in-first-erased.

But I did not want to relocate a drive enclosure daily. I required something small and easily carried – the easier the better and the more likely I would actually behave and take it home! Backup strategies dictate paranoia and discipline. Discipline is sloth’s foe and we are all, by inclination, slothful.

The cheapest solution I could find was this:

The Aluratek plug-in backup cradle. Blue means on, red means working.

For the grand sum of $24.95 from B&H, one of these Aluratek cradles was delivered, postage paid, and plugged into a USB port. Your naked drive of choice – it can be any 2.5″ or 3.5″ SATA drive – plugs into the top and is released by pressing the button, like on a toaster. While there’s no fan, the device sits in the open, so is reasonably ventilated and, given its light duty cycle after the first core backup, heat is not an issue. “Warm to the touch” describes it.

Opinions of the required size of Time Machine HDDs are all over the lot. Obviously, as a minimum the Time Machine HDD should be as large as the volume of data on your source HDD plus some space for historical back-ups of changed files. The more generations of data you want to store the larger the required TM HDD. On the other hand, I can’t see wanting to go back too far in time. This assumes I realize I have messed up before too much time passes, so that the last good version of whatever I messed up is still available. Further, as my internal HDD is relatively mature, meaning the rate of change of bytes in percentage terms is low, I tend to think too much excess capacity is a waste.

However, as my boot disk is 1.0tB I plugged in a 1.5tB 3.5″ SATA HDD into the Aluratek and let Time Machine do its thing. With only 400gB on the internal drive, 0.5tB – 0.75tB would have done fine, but the incremental cost of the larger drive, at some $30-50 more, is so low as to make no material difference in exchange for the peace of mind. The sledgehammer solution and almost certainly overkill.

Now I simply unplug the naked drive after ejecting it from the Desktop (right click on the mouse) and pop it in my shoulder bag before going home for the day. On reconnection, Time Machine recognizes it within 30 seconds and confers the appropriate green icon on the drive which appears on the Desktop.

I really suppose I should use a grounding strap when removing the HDD from the Aluratek cradle and an antistatic bag to transport it, but I am bothering with neither and all is well after a month of use. We’ll just see how it goes. With the internal redundant backup HDD in the MacPro I simply have iCal send me a monthly reminder to check that I can boot from the backup drive. But Time Machine backups are not bootable. So how do you check them? Well, there’s a clever Time Machine Buddy widget which tells you if everything ran smoothly – worth checking now and again. Typically, I’m finding incremental Time Machine runs are reported as no more than a minute or two in length by Time Machine Buddy, which provides a useful log of what was done by the application.

If the minimum 1 hour backup frequency of Time Machine is too frequent, you can use a free application named Time Machine Editor to extend it.

Another interesting point of discovery is determining how many remove/replace cycles the HDD and the Aluratek can handle. The HDD depends on contact strips and the Aluratek on wipers, both of which wear with use. If they survive a couple of years I will feel fine about my investment.

More paranoia:

I’m beginning to sound like Andy Grove of Intel fame (“Only the Paranoid Survive”) but my pictures are precious to me. So what if a large surge or electromagnetic wave takes out my two internal drives and the Time Machine drive simultaneously while the Time Machine drive is connected? I’m sunk. So I suppose I really should rotate two Time Machine HDDs with one always in the remote location.

Of course, the minute I adopt that strategy, some nut (or divine providence) will drop a Big One on Silicon Valley and then all my redundant drives are toast. But so am I. So in that case I do not care. On the other hand, if an earthquake takes out the Bay Area and I survive, maybe one of the two HDD locations gets lucky. Oh! boy, guess I need another 1.5tB HDD!

One note of caution. Time Machine software is also available packaged with an HDD in a white plastic box from Apple, named Time Capsule. This adds a hard disk to the software and, as is common with Apple products, places looks above longevity. Not only is the plastic case a very poor conductor of heat (in fact it acts as an insulator, trapping heat inside) the box has no fan, meaning it overheats. Further, it uses wireless for the data stream. You are going to trust your precious backup to flaky wireless? No wonder, then, that the web is replete with complaints of Time Capsules having high failure rates. Save your money. Buy your own properly ventilated, hard wired, external drive enclosure and have something that lasts longer than the warranty period, while saving money in the process.

The online backup alternative:

Why not just use an online backup service. In a word, because it’s useless for large files. Here’s why.

My upload speed on DSL is 0.64 megabits/second. At best. 1 megabyte=8 megabits, so that translates to 0.08 megabytes/second.

My Lightroom catalog is 87.66 gB, so it would take 87.66 x 1000/0.08/60/60/24 = 12.7 days to upload it for storage.

Now, apart from the fact that this would completely clog up my DSL, what do you think the chances are of an uninterrupted 12+ day period for this upload?

Then add another 53.2 gB for my iTunes library, and 28.4 gB for my iPhoto library and all the other things and …. well, you get the picture.

On line storage is simply not a practical answer with our slow broadband speeds. The cost is also high – $50-$100 a year and good luck getting more than a gigabyte or two in space. By contrast, the 1.5 terabyte hard drive I am using cost $140 and has a 5 year warranty, so the maximum cost is $28/year – and that’s for 1,500 gigabytes. Not to mention nearly instantaneous retrieval in the event of catastrophe. And by the way, what makes you so sure that the online service, operating in a competitive environment with razor thin margins, will be around tomorrow? Or that their backups are safe? Or what if some crook at their end steals your personal data? Sorry, this approach fails risk analysis on so many issues it is simply a non-starter for me.

On a related note, there’s something awe inspiring about having one or two terabytes in a jacket pocket. Doubtless, 2.5″ drives will have these capacities soon. They max out at 750gB currently, have very small 8mB buffers, are slow at 5400 rpm and expensive. Soon I expect that SDHC cards will take over. A terabyte in a stamp sized card. I still never cease to be amazed at what engineers and materials scientists have done with storage capacities. Imagine, your life’s achievements in exquisite detail on a postage stamp. Truly, modern storage technology is the hoarder’s dream come true.

Get ready to fry.

Earlier this week Apple announced the new iMacs in 21.5″ and 27″ screen sizes. The usual Cupertino Hype tells us there’s lots to like – bigger screens, slimmer, faster, etc. So it has an unusable high gloss mirror for a screen. A minor inconvenience for jewelry buyers.

But a moment’s review of the internal design gives one pause – and I’m speaking from expertise gleaned from having lost one iMac (a 20″) and almost lost another (24″) to bad thermal engineering.

Here’s how the new iMacs look under the skin:

The new 27″ iMac’s guts

Even those of you reading this without an honors degree in Mechanical Engineering (yes, I have one of those) who did not graduate at the top of your class (I did that too, around the time I took yesterday’s snap) can see the obvious design error in the older iMacs has been carried over to the latest iteration. The hot running CPU (because it is from a laptop, not built for desktop use) and the fan below are circled in red. The direction of the blast of superheated air emanating from this assembly is indicated by the green arrow. That hot air toasts the motherboard which is a seriously cramped and compromised design lifted from a laptop to ensure everything fits with Mr. Jobs’s thinness obsession.

I don’t think I need say more, even to readers who don’t know Farenheit from Celsius.

But wait, you exclaim. You said something about a toaster?

Why, yes. The bread goes in the right hand side, denoted by the yellow arrow. It has to be super slim, of course.

What goes around ….

A friend with an iMac like mine, the easy-fry 24″ late-2006 model doomed to early death owing to poor heat management, sent me this top secret photo of iMac engineers driving to their Labor Day barbecue and I felt I simply had to breach the strict oath of privacy to which I was sworn and share it with similarly afflicted readers.

iMac engineers on the way to the barbecue

I am reliably informed that the driver of the pretty red Alfa is none other than Steve Jobs.