Category Archives: audio

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The best ear buds I have heard: Wolfson’s Digital Silence DS-421D with noise cancellation

At the Mobile World Congress in Barcelona last month I caught up with Wolfson Microelectronics, who make digital converter chips and other audio components. They do not sell many products to end users, but are making an exception for the Digital Silence range of noise-cancelling headsets.

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The origin of the technology here is in the company’s 2007 acquisition of Sonaptic Ltd, specialists in micro-acoustics, or in other words getting good sound from mobile devices.

The Digital Silence range is unusual among ear buds in including noise cancellation. In other words, microphones on the outside of the buds pick up external sounds, phase reverse them, and add them to the input signal so that you hear more of the music (or voice, if listening to a call) and less of the external sound.

The new Digital Silence range has three models, of which I have been testing the DS-421D, which is set for general availability shortly.

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What you get is a stereo headset with clip-on controller, spare ear foams, mini-jack adaptors to cope with the fact that some mobiles wire up their 4-pole mini-jacks differently, USB charging cable, and a black zip-up carrying case. As with most headsets, there is also a built-in microphone and answer button. By default they are iPhone-ready, but will work with pretty much any mobile or player with a standard 3.5mm mini-jack output.

The controller has a rechargeable battery, charged by a USB connection, and specified to last for 14 hours of playback. A switch on the controller enables ANC and lights a green LED to show that the battery is OK. The ear buds work without ANC as well, so if the battery gives out you still have music. In a quiet environment, you might also prefer not to use ANC in case it adds artefacts to the sound.

A button on the side of the controller marked Monitor has a dual purpose. Press it to mute the sound; or press and hold to change the ANC filter. There is no display, but the unit plays one, two or three beeps to indicate the selection:

General: 20dB cancellation across a wide frequency band

Aeroplane: Low frequency cancellation such as found in an aeroplane is emphasised.

Office: Speech frequency cancellation around 200Hz – 1kHz is emphasised

Other products in the range are the DS-101A (around £30.00) and the DS-321D (around £50). I do not have a price yet for the DS-421D itself but was told “Under £100”. The DS-101A does not have selectable filters or a call/answer button.

Sound quality

Enough of the technology, how is the sound? This is what counts, and I am impressed. The DS-421D headset sounds excellent even without ANC engaged. No amount of noise cancellation would make them good if they were poor to begin with, and I suspect this fundamental good design is actually more important than the clever processing.

I used a variety of ear-buds for comparison. My regular set are Shure SE210 noise-isolating (not cancelling) ear-buds which I find easily out-perform the ones that come free with smartphones and iPods. I was taken aback by how much better the 421D sounded. The biggest difference is in the bass extension, but the sound is also smoother but without loss of clarity. These are the first ear buds I have used where you do not feel you are compromising by not using over the ear headphones.

The noise cancelling works. Don’t have unrealistic expectations, these will not deliver “digital silence”, but they will substantially reduce the noise. It is a bit like shutting it behind a door. There is also a slight change in the quality of the sound, for the better in my opinion, being a little richer than before. I used the DS-421D on an aeroplane and on the London Underground and had worthwhile results in both cases. I could have the volume lower and still enjoy the music.

I also compared the DS-421D to a set of Sennheiser PXC 300 foldable noise-cancelling headphones. The PXC 300 was slightly more effective in killing background noise, but the reason I tend to leave these at home is that they are bulky and use two AAA batteries which give out if I forget to switch them off. The DS-421D is more convenient. As for sound quality, it is close and I might even give 421D the edge.

The DS-421D is mainly for music, but I found the headset functionality useful too. I used it for Skype on a Windows 8 tablet and it worked much better than using the built-in microphone.

Design

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The design of the DS-421D  is excellent in terms of technology, but I am not so sure about the ergonomics. The length of cable between the ear buds and the controller is short, so you cannot clip the controller to your belt. It must be on your collar or perhaps top pocket. You could leave it dangling, but it is heavy enough to be a nuisance if you do.

Visually, the design looks a bit geeky to me; not unattractive, but I can imagine the DS-421D losing out among the more fashion-conscious purchasers.

Conclusion

Regular traveller who likes music? I recommend you give these a try. Now you can have noise-cancellation and high quality sound and a small, light headset.

Technical addendum

Wolfson’s noise-cancelling system is called myZone ANC (Ambient Noise Cancellation) which the company says uses “feed-forward, rather than the usual feedback systems”.

What is that then? I hunted around and eventually found Wolfson’s white paper on the subject*. Here is an illustration of feedback versus feed-forward:

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The figure on the left is a feedback system where the microphone is placed between the loudspeaker and the ear. In the feed-forward system the microphone is external so that the external noise is detected, inverted and added to the input. An advantage is that this does not require a sealed enclosure around the ear.

The main problem with implementation is time-aligning the cancellation signal with the input signal. Wolfson’s solution:

By placing microphones at the rim of the headphone, the ambient noise signal can be acquired and driven to the loudspeaker in advance of its arrival at the eardrum, thus compensating for the intrinsic response time of the loudspeaker.

The illustration in the paper shows a ring array of 5 microphones around each headphone, but since the DS-421D is a small earbud I doubt it has such an array. There is only one visible microphone aperture. Still, this gives some indication of the technology used.

Wolfson did not invent feed-forward as far as I know, so its innovation is in the area of how to achieve accurate time-alignment of the cancellation signal.

*The paper is called Ambient Noise Cancellation for Headphones and Headsets. I cannot find a direct link, but if you go here and search for resources for the WM2002 you will find it.

High resolution downloads from Kate Bush

The official Kate Bush website is selling high-resolution 24-bit downloads of her new album 50 Words For Snow. There is even a detailed explanation of why the downloads are on offer and how they are created, credited to Bush’s organisation “The Fish People.”

The Fish People state that CD technology is old (true) and inadequate (controversial):

…despite the huge improvements the CD brought with it, the state of technology at the time introduced some limitations in the quality of audio that could be recorded and stored on the CD. The many advantages of the CD mean that it has continued to be the default consumer format for many years. However digital studio technology has moved on immensely.

According to this account, Kate Bush mixes her recordings to an analogue 1/2 inch 30ips tape. Then she masters this to 24/96 digital, which as she states:

increases the dynamic range and frequency response of the digital process well beyond the levels perceivable by the human ear.

The master is normalised for CD’s 16/44 format, which means the volume is adjusted to use all the available headroom. However for the downloads there is no normalisation, and if the description is to be believed, the files are the same as those used for the studio mastering.

Curiously the files are offered in uncompressed .wav, which makes for a bulky download:

With these files we also wanted you to be able to hear the recordings as close as possible to the way it sounded on the analogue master. For this reason we have chosen only to make available 24/96 .wav files in an uncompressed format. By not using compression we avoid any further possibility of introducing errors or noise into the files. The downside of using uncompressed files is that the files are large and will take a long time to download.

This is unnecessary since formats like FLAC and ALAC compress the size of the files but do not lose any musical information; you can expand them back into WAV without any loss.

The files sound excellent as you would expect. It is worth noting though that efforts to identify audible difference between 16/44 and 24/96 in blind listening tests have been mostly unsuccessful, suggesting that they sound either the same or very very close to the human ear, when careful level-matched comparisons of the same master are made. If the high-res files sound different from the CD, it is more likely because of other factors, such as additional audio compression (as opposed to lossless file compression) which does change the sound, or additional equalisation applied when mastering the CD.

Another quibble I have with this offer is that it gives the keen purchaser a difficult choice. Do you want the CD with its attractive hardbound mini-book and artwork, or download which costs more and comes with no artwork but may sound better? The keen fan has to buy both. By contrast, recent Peter Gabriel CDs have a code that lets you download the high-res files as well for no additional cost.

That said, kudos to Kate Bush for making available such high-quality downloads.

AVI announces ADM40 active floorstanding loudspeakers

The British hifi company AVI, based in Nailsworth, Gloucestershire, has announced the ADM40 active floorstanding loudspeakers, promising that “Everything is new, different and improved” versus the successful ADM9 and ADM9T, reviewed here.

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Here is what we know about the ADM 40 (the hole in the above picture, by the way, will hold a status display). All subject to change, these are informal announcements on a forum:

  • Measure 90 x 21 x 30 HWD.
  • Three-way speaker system.
  • Two analogue inputs and four optical digital.
  • Stereo outputs for an optional sub-woofer. Without sub they are “-6dB at 45Hz”.
  • Remote with on/off and filter selection.
  • £3000 with Cherry or Walnut finish. Rosewood, Piano White or Black Lacquer £3750 delivered to the UK.

This price makes them more than two and half times more expensive than the ADM 9T. The challenge for AVI has been to make speakers that can reasonably be described as “full range” and which improve on what the smaller 9T already delivers. Three-way loudspeakers have theoretical advantages, because each drive handles a narrower range, but the design is more complex thanks to the crossover (of course this requires three amplifiers in an active system) and potential interactions between the different drives. Add a sub-woofer into the mix and the complexity increases. Large loudspeakers are hard to do well, but of course well worth it when successful.

Squeezebox server gets DLNA support: play FLAC on iPad

Logitech has released an update to its Squeezebox server, now called Logitech Media Server (LMS), and now at version 7.7.

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One of its new features is DLNA support. DLNA is a standard for serving and playing media across devices. Note though that although LMS is now a DLNA server, it does not transcode, so if for example you store music in FLAC format, a Sony PlayStation 3 will not be able to play it. Many other DLNA servers do support transcoding, so for example Illustrate’s Asset UPnP will stream FLAC as MP3 so that a PS3 will play it correctly.

This is still an interesting new feature for LMS, particularly as you can store images and videos as well as music.

One thing I have been gently investigating for some time is the best way to get a Squeezebox FLAC library playing on an Apple iPad or iPhone. I have had success with Asset UPnP but only with transcoding. After installing LMS 7.7 I tried the 8player lite DLNA client and was pleased with the results.

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I selected the Logitech Media Server and was soon enjoying music through the remarkable-considering-the-size iPad speaker:

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8player lite has a working free version or you can purchase for a modest price and get full features. There are some other DLNA clients you can try, but they do not all support FLAC. SmartStor Fusion works well with Asset PnP.

An ugly dialog from Spotify

I am a big fan of Spotify, mainly because it works so well. Search is near instant, playback is near instant.

I understood when, under pressure from the music industry, it limited the value of the free version by restricting the hours of play and the number of times you can play a specific track.

This is ugly though:

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Spotify says:

From today, all new Spotify users will need to have a Facebook account to join Spotify. Think of it as like a virtual ‘passport’, designed to make the experience smoother and easier, with one less username and password to remember. You don’t need to connect to Facebook and if you do decide to, you can always control what you share and don’t share by changing your Spotify settings at any time.

Why care? Privacy? Because you might want Spotify but not Facebook?

I would put it another way. I am wary of putting Facebook at the centre of my Internet identity. If others follow Spotify’s example and the Web were to become useless unless you are logged into Facebook, that would give Facebook more power that I would like.

If for some reason you want to withdraw from Facebook, why should that affect your relationship with Spotify? It is an ugly dependency, and I hope that Spotify reconsiders.

See also Cloud is identity management says Kim Cameron, now ex-Microsoft.

Review: Verbatim’s USB audio bar – simple, well made, good sound

If you are in the habit of watching video or listening to music on a laptop, you will know that the average laptop has poor sound quality. That is partly because most laptop speakers are an afterthought, and partly because it is not easy to fit speakers of any quality into a laptop case.

External speakers are the answer, but while there are plenty to choose from, they can get in the way.

The Verbatim 49095 Portable USB Audio Bar Speaker is a neat solution. It is designed to fit on top of a laptop screen.

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While that may sound precarious, the unit is cleverly designed with tabs at the front and a twist-down peg at the back which means it fits well on almost any laptop screen.

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I was impressed with the sound, considering the modest price of this product, which retails at £14.99 or less. It is a vast improvement on the built-in speakers in the Dell laptop I tried. No, it is not as good as two separate loudspeakers positioned either side of the laptop; but the audio bar takes up almost no extra space and would easily tuck into most laptop bags when not in use.

Unfortunately you do need a laptop – running Windows 7, Vista, XP, or Mac OS X 10.1 or higher. Apple’s iPad has no USB port, and there is not an option to use an audio cable instead.

The unit is well made, works with USB 2.0 or 3.0, and claims output power of 2 watts RMS.

Recommended.

Review: Audéo Perfect Fit earphones

Audéo Perfect Fit earphones are designed to replace the set you got bundled with your smartphone or music player. The earphone set includes a microphone and a standard multi-function button, so that on an iPhone or many other phones you can answer or decline calls, pause and resume music, or skip to the next track.

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There are a few unusual features. One is the shape of the earbuds, which have a distinctive “leg”. In order to fit them you first attach one of a range of silicone or foam ear tips. Then you place them in your ear with the legs pointing up and forward, and the cable draped over the back of the ears. It sounds fiddly, but it is easy enough in practice, and gets you a secure and comfortable fit.

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The supplied manual does an excellent job of explaining fitting. There is also an optional ear guide which adds a shaped cable clip that hooks over your ears. This was not supplied with my review package, the PFE 02x, but does come with the more expensive PFE 12x or can be purchased separately. I found the fit was fine even without the clip.

The extra accessories, including the audio filters described below, are a point of confusion, as the manual in the PFE 02x lists them under “Package contents” even though they are not supplied. No doubt some customers complain that parts are missing; I would have done the same, except that I checked the product web site and external packaging which correctly shows that the only accessories in the PFE 02x pack are the silicone ear tips.

The next special feature is that each earbud is fitted with a passive audio filter, which can be changed according to preference. The PFE 02x comes with a single green filter, which you can see in the picture above, while the PFE 12x comes with gray and black filters and fitting tool.

The colours are significant. The black filters are said to amplify bass and high frequencies (what audiophiles call boom and tizz). The gray filters are meant to emphasize mid-range frequencies, while green are described as offering “perfect bass”.

According to Audeo:

In-house studies have shown that, when headphones exactly reproduce the response curve of the unobstructed ear, most people hear the sound as being very aggressive.

The response curve of Audéo PFE in-ear earphones is a compromise between a frequency range that compensates for the curve of the unobstructed ear and one that emphasizes bass and high-frequency sounds. This is what most people prefer.

In order to cover the widest possible range of user preferences we offer three audio filters.

Unfortunately the only filter I have tried is the green one supplied with the PFE 02x. However I am a little doubtful about the above explanation. The goal of hi-fi reproduction is neutrality, so that you hear whatever the musicians and engineers who created the sound intended. I appreciate though that when it comes to earbuds used on the move in all sorts of noisy environments, it does not makes sense to be purist about such things. Further, it is not realistic to expect earbuds to deliver the kind of bass you can get from full-range loudspeakers or even from high quality over-the-ear headphones, and indeed this is not the case with the Audéo. Still, what you care about is not the theory but the sound. How is it?

I carried out extensive listening tests with the Audéo earphones, comparing them to a high quality Shure earbuds as well as to a standard Apple set. My first observation is that the Audéo earphones do fit more snugly and securely than either of the others I tried, when fitted correctly, and that this close fit goes a long way towards obtaining a better and more consistent sound.

Second, I soon identified a certain character to the Audéo sound. In comparison to the Shure, the Perfect Fit earphones are slightly softer and less bright. On some music this was a good thing. I played My Jamaican Guy by Grace Jones, which has a funky beat and bright percussion. On the Shure the track was a little harsh, whereas the Audéo tamed the brightness while still letting you hear every detail. With Love over Gold by Dire Straits though, which is already a mellow track, I preferred the Shure which delivered beautiful clarity and separation, whereas the Audéo (while still sounding good) was less crisp. Daniel Barenboim playing solo piano sounded delightful though with slightly rolled off treble.

I did feel that both the Audéo and the Shure improved substantially on the Apple-supplied earphones, as they should considering their price, though even the bundled earphones are not that bad.

The strength of the Perfect Fit earphones is that they never sound bright or harsh; I found them consistently smooth and enjoyable. The sound is also clean and well extended, considering that they are earbuds. Isolation from external sounds is excellent, which is important if you are a frequent traveller.

The weakness is that they do in my opinion slightly soften and recess the sound.

That said, it may be that the other filters give the earphones a different character, and if you have the pack with a choice of filters it would be worth trying the variations to see which you prefer.

I may have been imagining it, but I felt that the earphones sounded particularly good with Apple’s iPhone.

Conclusion: a good choice, especially if you like a slightly mellow and polite presentation. If possible I recommend that you get the more expensive packs that include a case as well as alternative filters and the optional ear clips.

   

Now you can rip SACDs

Sony’s Super Audio CD (SACD) is an audiophile format featuring high resolution and multi-channel sound. The discs are are copy protected, and until now it has not been possible to create an exact copy. Of course you can capture the analogue output and re-digitise it, and certain players from manufacturers such as Oppo enable you to capture digital output converted from Sony’s DSD (Direct Stream Digital) format to high-resolution PCM (Pulse-Code Modulation); but still, it is not an exact copy.

Ripping an SACD is still not that easy. The crack depends on getting hold of an early model of the PlayStation 3 that has not been updated to the latest firmware. Recent PS3s do not play SACD at all, plus you need firmware of 3.55 or lower, before Sony removed the capability of running an alternative operating system. There is no downgrade path, so it is a matter of scouring eBay for one that has not been updated.

Once you have the right hardware you can follow the instructions here  to rip the SACD:

SACD-Ripper supports the following output formats:
– 2ch DSDIFF (DSD)
– 2ch DSDIFF (DST) (if already DST encoded)
– 2ch DSF (DSD)
– mch DSDIFF (DSD)
– mch DSDIFF (DST)
– mch DSF (DSD)
– ISO (due to the 4GB FAT32 size limit on the PS3, files will be splitted when larger)

There is some discussion of the procedure here from where I have grabbed this image:

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Is it worth it? Good question. There are SACD enthusiasts who swear that DSD reproduces sound with a natural fidelity that PCM cannot match. On the other hand, researchers conducted a test showing that listeners could not tell the difference if the output from SACD was converted to CD standard PCM. I have also seen papers suggesting that DSD is inferior to PCM and may colour the sound. Expect heated opinions if you enter this debate.

Nevertheless, there are many great sounding SACDs out there and the format is not completely dead. Universal Japan, for example, issues SACDs made of SHM (Super High Material) at premium prices, and whether it is thanks to the super super technology, or simply clean mastering from good tape sources, these are proving popular within the niche audiophile market.

The fact that these discs cannot be perfectly ripped is part of the appeal from the industry’s perspective. Now that is no longer the case, and the torrent sites will be able to offer DSD files with full SACD quality.

Warring models of music distribution

How should we pay for the music we listen to? In the digital, internet era, it seems to me that there are three business models.

In the first model, you pay for a lifetime right to each album or track you want to add to your collection. This is the most similar to what we are used to from purchasing physical media like records or CDs. You do not own the music of course; all you have ever purchased is a licence to listen to it.

Until now the digital equivalent has been downloads as offered by Apple iTunes or Amazon’s MP3 store. However, Apple has now announced iCloud, which extends this model to de-emphasise the actual download. You download a track to play it on your device, but there is no problem if you have more licenced tracks than you have space for; you can just download the ones you want to play. You can also “upload”, but when you do this, you do not really upload the tracks, but rather just inform iCloud’s database that you are licenced for them.

The second model is where you subscribe, giving you the right to play anything that your music provider has to offer. The most successful example is Spotify, which has a superb client for Mac and PC that offers near-instant playback of any of 13 million tracks.

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An advantage of this approach is that it is naturally social. Since everyone has access to the same library, you can share playlists easily.

The third model is where you do not pay at all. In pre-digital days, you could listen to the radio or swap tapes with friends. Now almost anything is available, legally through Spotify (though now restricted to 2.5 hours per week and 5 times per track), or illegally through countless sites easily found through Google, or through copying your friend’s hard drive stuffed with music.

Personally I am a fan of the second model. I think musicians should be rewarded for their work, and that all-you-can-eat licencing is the best and fairest approach, taking advantage of what technology enables. Buying a lossy-compressed download with a restrictive licence is also poor value compared to buying a record or CD.

I get the impression though that the music industry is set against the subscription approach. Apple seems reluctant to embrace it, hence iCloud is still tied to the first model. Spotify still has it, but the company now seems to be putting increasing emphasis on downloads and locally stored music, which is strange given its original concept, as well as making its ad-supported free streaming account less attractive.

The business reasoning, I guess, is a belief that selling music piecemeal is more profitable, and exploits the collecting instinct that has served the industry so well in the past.

The risk is that the third model will sweep it aside.

Review: Q2 Internet Radio, colourful minimalism

This one is nearly brilliant. The Q2 Internet Radio is a cute 10cm cube which does just one thing: play internet radio.

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This gadget is from the UK-based Armour Group, and the company has endeavoured to learn the lesson of Apple and to create a device that is attractive, usable, and avoids the distraction of myriad features that are rarely used.

The Q2 supports just four channels, selected by you. You change channel by turning the device, with the number on top indicating the current choice. Increase volume by tilting the cube back, decrease by tilting it forward, mute by turning it on end.

Round the back there is an on-off button, a USB port and a headphone socket; and that is about it for controls. The rechargeable battery gives around 14 hours playback time according to the manufacturer. An LED that is just about visible through the speaker grille shows the status: green for online, red for offline, flashing amber for low battery.

The Q2 comes in a smart box and is just asking to be given to someone, a gift that even technophobes will enjoy.

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Setup is a matter of downloading and installing an application on your Windows or Mac (Linux not supported yet) and then connecting the Q2. The application has a bold and colourful drag-and-drop approach, and it is a matter of moments to select a wifi network, enter the security key, and then select stations or podcasts for the four available channels. Just in case you did not know, there are thousands of internet radio stations, though quality varies and I found that some channels did not actually play. Still, you will have no trouble finding four good ones.

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Now, I have a few reservations about this device, but let me start with the good news. Operating the unit is genuinely easy, it looks good presuming you find a colour you like, and sound quality – though mono unless you use headphones – is remarkable considering the small size. Here’s why:

The Q2 Radio uses a custom designed full range 2.4” 4 ohm drive unit chosen for good sensitivity and matched to the 140 Hz tuned port enclosure.

Biquad DSP filters are used to voice the sound, giving a smooth listening response and added bass extension from the speaker system.

The amplifier is a high efficiency Class AB BTL type, optimised for battery operation, giving typically less than 0.1% THD under normal operating conditions. The use of a Class AB rather than Class D type amplifier results in both lower noise and distortion.

So far so good; but this device does have frustrations.

I am all in favour of minimalism, but wonder if this has been taken too far here. What if you or those who share your home want more than four channels? Changing the presets is a hassle. I also found that controlling the volume control by tilt is not really a great idea, since it is easy to over-shoot and have to tilt it the other way.

The Q2 feels well made, but I noticed that the rubberised surface picks up dust easily.

Now, there are a couple of things that Amour could do to improve the Q2. The first is to add Bluetooth with A2DP support, so that it could act as a remote powered speaker for a smartphone.

Second, the Q2 is crying out for an app that would let you control it from a smartphone. As it is, you have to connect it to a computer via USB to make any change to its settings. An app would be more elegant, and allow the Q2 to take real advantage of the thousands of internet radio stations available.

As it is, this is an expensive device for what it does. It is worth noting a some of the limitations that are inherent to its design. It needs to be in range of a wifi connection, so it is not suitable for travel, and most hotspots will not work because they require a login. It is not suitable for a bedside radio, since it has no clock or alarm. It does not support USB charging, so you need to use the supplied mains adaptor.

A few flaws then; but the Q2 is FUN and would make a delightful present. Yes, you can get more elsewhere for the same price; but value for money is not what this product is about.