Saturday, May 2, 2015

Review: RIVA Turbo X - Vrrooommmm!!!

Despite the sheer number of Bluetooth speakers that flood the market every day, it is still quite seldom that a unit manages to stick out of the whole crowd in some particular way. The B&W T7 stood out because of its funny design and mediocre sound, the Fugoo stood out because of its ruggedness and unique approach to 360° sound, which worked so much better than what UE is trying to sell as 360° and the JBL Charge 2 stood out because of all the artefacts and distortion noises it managed to produce... But now a rather unknown company "ADX" (Audio Design Experts) came up with an own brand called "RIVA" and a first own product, the Turbo X which is a portable battery driven Bluetooth speaker. Jump in to see why the RIVA Turbo X manages to set itself apart from all the rest.

At first look it might seem as if the Turbo X was nothing exceptional, just another BIG Jambox like box similar to all the others. But digging closer ADX is not just a company rebranding chinese stuff or using drivers from Soundmatters and putting them inside a strange patterned hull designed by Steve Behar, but ADX consists of real audio engineers and is led by audio engineering legend Rikki Farr. They own several patents including their own technology "Trillium™" together with some custom designed drivers that found their way into the Turbo X. This is not just a speaker for all the kiddies out there who want to crank their latest Pitbull song at the playground, but rather a portable speaker for the serious music enthusiast, who demands true reproduction quality without any additional processing added or other intrusive dynamic compression distorting the original recording just to make it appear louder or "better".
I was interested in the Turbo X since the announcement last year, but as the release in Europe seemed to be delayed repeatedly, I finally contacted RIVA and after talking to Mr. Farr in person, they decided to send me a unit for a review, which I am pretty happy about, as otherwise I would have to wait for an uncertain period. Currently you can only order it from or the British store, it is still a bit unclear when it will become available in Germany or the rest of Europe.

Sent directly from California the RIVA Turbo X arrived some days later at my house and got me pretty excited to finally open the box. Inside you will find the speaker wrapped inside a plastic bag and covered by some additional protective plastic film at the top and bottom of the speaker. You will also find an own charging unit including a deattachable power-cord. You will either need a European plug-adapter for the included chord, or you can attach your own 2-pole cord. The charger works for both 110 and 220V and delivers 19V at 3.5A. The speaker cannot be charged through USB etc, you must use the included charger, which is understandable as it would probably take 2 days to fully charge the Turbo X at 5V only with this energy requirement.

The included manual is well written and pretty simple thanks to lots of drawings. There is also a diagram which suggests the best placement for the Turbo X to be in a corner:

Inside you will also find an aux-wire with cinch-connectors at the other end and while I was first wondering which purpose this wire might have, later it revealed itself as a phono-wire for the speaker's additional phono-mode to be able to attach a turntable directly! Wow, this is the first portable speaker that I know which gives you that option. Not sure how many are actually going to do this, but if you are a vinyl collector and happen to own a USB-powered turntable, just use the Turbo X as a monitoring system on the go or a small portable party machine to play your records through it with the Turbo X delivering the power for the turntable at the same time!

The design of the Turbo X is pretty clean and simple at the same time, just a box with rounded corners, sizewise it is quite comparable to other speakers in this class like Bose's Soundlink III, or the Infinity One, Braven HD etc, which all weigh around 1.5kg. The elegant RIVA design has some Apple-like quality to it, especially in white with a clearly readable layout for the illuminated top controls. I went for white as it should be more forgiving if used oudoors on a sunny day. I also think that with the white colour you won't see finger prints that easily, as I am not a huge fan of the glossy finish used for both the top and bottom plate and in fact it took me some time to finally force myself to remove the protective films.

Although the speaker definitely looks slick in an interior enviroment, for outdoor use this kind of glossy finish is the worst you can wish for. If I intended to use the Turbo X during garden work for example, I would be afraid to touch it with my dirty fingers full of sand all the time in order not to scratch it in some way. Many other portable speakers are much more resistant due to other rubbery or fabric-like materials as you can find on the Fugoo or the UE Boom for example. I wouldn't like to use the Turbo X without any additional protection neither during transport nor for any outdoor activity, which is a pity, as it is even claimed to be weather resistant, so in reality it could definitely take some treatment, it is just that it won't look that great afterwards.

Meanwhile RIVA also offers an own additional transport bag on their site, but you have to buy it as an extra, as it doesn't come with the speaker. The bag has an own compartment at the front to accomodate the charging unit and it is so large that the Turbo X would even easily fit in with some extra silicone skin. Yes, if I was in the design team I would indeed go that far, to offer some protective rubber skins as extra, that you can wrap around the speaker, similar to Fugoo's jackets, but much more simple and rather similar to all the soft hulls you can get for most smartphone models. Even the Bose Soundlink Mini has its own covers, such skins may even change the design of the speaker completely thanks to different colors or patterns. "Dressed" the Turbo X would rather look like a Braven HD, but for home use simply take this skin off and leave the speaker "naked"... just a freaky idea!

At the back of the speaker you will find all the necessary ports as well as an own dedicated battery on/off switch and a battery indicator LED. There is also an USB-out which allows you to charge other devices on the go, this also works when the speaker is in off-state, which in reality is more of a "standby-mode". There is an own micro-USB data-port, which is probably there for possible updates. One rubber foot at the bottom is removeable to be used as protective cover for the ports against water, dust etc, quite clever and nicely done.

The overall build quality of the Turbo X is definitely top notch, it looks sturdy and high quality, although as already mentioned I am a bit afraid of the glossy surfaces for portable use.
The Turbo X is not a compact speaker anymore, but it is not huge either. Thanks to the rounded edges it is easier to be slipped into some bag in contrast to a BIG Jambox for example, which has sharp corners all over. The Turbo X is not a speaker for the jacket pocket, but still to be easily regarded as "portable", while I wouldn't call a B&O Beolit 15 or Klipsch KMC-3 quite portable anymore.

The Turbo X has a kind of proximity sensor. As soon as you move your hand close to the top surface the controls will light up. If the Turbo X is turned off, only the power button will light up, so that you should be able to turn it on even in complete darkness. For portable use and for charging of the internal battery the dedicated battery switch must be active. I am not quite sure what's the reason for that switch, but it is probably there to disable any accidental power-on during transport, as the buttons are all touch sensitive only and do not need to be pressed at all. Usually the buttons work pretty well and might even react a bit too sensitive, with exception of the larger power and turbo buttons which need a bit more patience to make them work. I found that keeping the finger down for at least one second works best, while at the beginning I tried to press them harder etc, which didn't seem to help at all. Meanwhile I was told that the larger buttons are indeed designed to work like this. You have to keep the Turbo button touched for a second to enable Turbo to avoid any accidental activation. The same goes for the Power button, you have to keep it touched in order to turn off the speaker.
Another reason for the extra battery switch could also be if the speaker is going to be used as a stationary device and the battery won't be charged if the button is off. This way you might prevent the battery to be charged too often. Just remember to turn it on if you want the battery to be fully charged for the next outdoor mission.
It is not that easy to check exactly how long it takes to fully charge the battery as the battery indicator at the back will only flash showing the charging procedure if the proximity sensor becomes active. Otherwise it is not visible if it is currently being charged or not because normally the battery indicator is off. Only when the speaker is run from battery the indicator will glow permanently, unfortunately it is not possible to tell how much battery life is still left from the indicator alone. It will just glow green constantly to become orange at some point or red, when battery is really low. From my own tests it seems that it takes around 2:30 hours to fully charge the Turbo X, which is pretty awesome, as many speakers take much longer to charge, but discharge much faster at the same time. Battery life is classleading too. RIVA claims 26 hours at 75dB which is quite impressive. During my own tests the Turbo X played for 6 hours at its maximum volume with Turbo enabled until it shut off on its own. If you keep in mind how loud this speaker can play and remember B&O stating 24 hours for their Beoplay A2, while in reality it already gave up after 50 minutes at its maximum volume being nowhere close to the loudness of the Turbo X, then even such sanctimonious disclaimers like the one B&O published afterwards for the Beolit 15 can't help to reveal their battery life claims simply as eyewash:  
Obviously, if a product can play extremely loud, and you turn the volume all the way up, it uses a lot more energy. It’s exactly the same as with cars and fuel economy – the faster you drive, and the more you accelerate, the more fuel you use.
The only real battery life indicator for the Turbo X is available through the own RIVA Ground Control app, which is available for iOS and Android. Within the app you will get an exact percentage of the charge that is left, and not only some vague colour representation. It is a pity there is no own Bluetooth battery symbol like so many speakers meanwhile manage to add to the top status bar of an iPhone etc. I observed close to 5% battery loss per hour, which would indeed hint at a battery life of +20 hours at comfortable listening levels. At least the Turbo X is prefectly usable at high levels as well and won't let you down by suddenly reducing its volume to half or other insidious tricks.
The only letdown I discovered was a very quick self discharge when the battery switch at the back was kept active. I noticed around 10% of battery drain per day without having used the speaker at all. So better keep that button off most of the time if you are not planning to use the speaker and finally activate it before use. I also noticed a self-discharge when the speaker was attached to mains. It usually charges pretty quickly, but after having kept it attached for a day without usage I noticed the next day that battery was again down to 96%. It seemed as if the speaker got fully charged but then it started to discharge on its own again, although it was kept attached all the time.

With the app you can also control most of the functions available through the speaker like enabling surround mode or activating "Turbo" mode, more on that later. There is also an own mute-button, which works just like the one on the speaker. Within the app track controls are availabe as well, which are unfortunately missing on the speaker. Interestingly the app's track controls only work with the original music app, but do not work globally for any other streaming app like Spotify etc. Maybe this could be changed with a future update.

Depending on the colour of your Turbo X you can also switch the background colour for the app between black and white to, a nice touch if you ask me. Another feature is the ability to turn the speaker off directly through the app, a pity the Turbo X cannot be turned on remotely as well, like it is possible with the UE Megaboom. This would make usage even more versatile.
The only function available through the app which you cannot attain through the speaker is changing voice prompts for tones. If voice prompts are active the speaker will always tell you that "Turbo is paired" or it will say "Surround" if you activate surround mode, but most annoying is the extremely loud engine-sound if you turn on "Turbo"-mode. Therefore the first thing I did was to disable voice prompts. The speaker will still play some particular status tones when turned on or off. The welcome tone is pretty pompous and much too loud, with some kind of bass heavy orchester hit which is also of no avail because it doesn't play directly after turning on the speaker, but needs some seconds after you have touched the power-button. Sometimes I was not sure if finally I managed to turn the speaker on or not. The Turbo X will also beep if you activate Surround or Turbo. It will also beep if you change volume directly through the speaker's buttons. Unfortunately all these tones are all played at a constant volume and don't become softer if you turn the volume down for example. If you are playing the Turbo X at a low level and activate surround it will beep very loud, the loudness of these beeps should be bound to the actual volume of the speaker. I think this could also be changed with a future update, which is to hope for. I would also welcome a third "silent mode" to be available through the app which would finally allow to deactivate all tones and beeps.
Volume control on the Turbo X is mirrored btw, regardless if you control volume through the speaker an iOS device or the app it will be always in sync, which is great as there is no hassle to deal with separate volume controls. Moreover the volume curve of the Turbo X seems to be logarithmic, it needs many clicks until the speaker gets finally loud, which is exactly contrary to how the Infinity One or the JBL Charge 2 handle volume control. They become loud pretty quickly without becoming any louder during the last steps anymore. Despite having just 16 dedicated volume steps for the Turbo X it still allows for a fine enough volume control especially at lower levels, kudos to RIVA to really have put some thought into this, I would still have loved to have double the steps, as sometimes the jumps in volume might be a bit rough at higher levels. With more steps the Turbo X would even allow better volume control at very low levels, I could imagine the very first volume step being lower than it is now for example.
Bluetooth pairing mode is already active the very first time you turn the Turbo X on. It also supports aptX for best quality Bluetooth streaming and all non-Apple devices. Unfortunately there is no wireless stereo pairing with a second Turbo X. A feature which would definitely elevate the speaker into real Hifi-territory. It is strange that RIVA didn't consider this feature as meanwhile many much cheaper speakers support this feature by default, unfortunately there is not a single serious sounding one that would justify that function other than some gimmick. At least the upcoming smaller Turbo S will support stereo pairing according to RIVA's webiste.
To pair the Turbo X with a new device, you have to keep the Bluetooth button touched for some seconds and the speaker jumps into pairing mode playing some sonar-like sound at the same time. The connection to the previous device is broken in this case, the Turbo X does not support multipoint pairing with several Bluetooth devices simultaneously. But the Turbo X has at least a very efficient connection strategy with already paired devices. It always connects to any device present that was already paired once. Many other Bluetooth speakers don't manage this without problems, they will still search for the latest device and simply refuse any automatic connection to any other known device which might be currently present. The JBL Charge 2, the Infinity One and even the Denon Envaya Mini come to my mind here among many others. The Turbo X finally manages this, although when both known devices are present at the same the Turbo X will still connect to the latest one, so otherwise turn off Bluetooth for the first device before turning the Turbo X on, or jump into pairing mode forcing a connection from the other device at the same time. Bluetooth reach is pretty solid, it doesn't seem classleading, but I didn't detect any hiccups etc. The Infinity One has a considerably worse Bluetooth reach and might already start stuttering from 2-3 meters away if placed directly on the ground. Mostly the Turbo X also managed to reconnect on its own in case Bluetooth connection got lost, but in such a case the app didn't work properly anymore and would only tell you to reconnect to the speaker despite being already connected. It only helped to establish a completely new connection either by repowering the speaker, or cancelling the connection from your device and reconnecting again in order to make the app recognize the speaker as normal.

I found some other slight bugs with the app, which will probably get sorted out soon by some update. But currently if you activate "Turbo" through the app instead of the speaker-button directly after powering the speaker on this will result in some strange compression effects including volume fluctuations which can become noticeable with some tracks. As long as you don't use the hardware-button this problem will remain but disappears immediately if you activate or deactivate Turbo through the speaker once instead of the app. There is another slight bug which makes the loudness jump back to a lower level every time you switch between different sound targets on an iOS device, or even during track-changes etc. I noticed that problem with Android-devices too and it was hardly possible to keep the speaker at maximum volume all the time, as it always tended to fall back one notch. Although volume is mirrored between speaker and iOS device, it was not possible to increase volume again through the iPhone's volume buttons or the volume slider but only through the app or directly through the speaker's own volume buttons. This fact gave me quite a hard time for my very first comparison videos, where I didn't notice this issue at first and wondered why the Turbo X didn't play as loud as I had remembered it before.

The Turbo X doesn't have any own aux-switch. If you connect an external device through the 3.5mm plug, it will automatically detect any external audio source playing and automatically switch to this. In this case Bluetooth remains still active and you can switch back to your Bluetooth source by stopping playback from the wired device. If auxiliary input is active the Bluetooth light will become green, otherwise it glows permanently blue to signalize an active Bluetooth connection.
You can also lock the touch sensitive buttons by keeping the mute button and volume - button touched for 3 seconds, this will activate lock-mode and the light will glow red in this case. In this mode no button will react to any touching, but you can still control the speaker remotely through the app. To deactive this mode keep the same buttons touched for 3 seconds again.

Of course there is also an own speakerphone functionality built in. I don't use this often usually on any speaker I owned so far, but when I tested it per chance the caller complained that he couldn't hear me well, at least I heard him very well because his voice came through clear and was spread to all directions. The Turbo X should be well suited for conference-calls as thanks to its particular driver layout everyone in the room should get perfect audio.

Therefore let's now have a look at the internals of the Turbo X, which are pretty impressive for a portable speaker: first being the 7 transducers that are built in with 3 of them being active drivers together with 4 additional passive radiators, all of them working on opposite sites so any unwanted vibration is cancelled out. Second being the amplifier, which is claimed to deliver 45W and is quite powerful for a portable speaker in this class if you keep in mind that the Infinity One has only a 25W amplifier built in (I am not talking about B&O's 180W claims for the Beoplay A2, which in reality are made up out of thin air, as the A2 doesn't even come close in overall loudness to the RIVA Turbo X). All drivers are designed by ADX including the passive radiators which are not simple vibrating membranes but rather built like real active speaker drivers. 2 of the active drivers are located at the sides with only one driver centered at the speaker front. ADX's custom Trillium algorithm finally performs an upmix of the 2-channel stereo signal into a 3-channel sound. This way ADX manage to offer a considerably broader soundstage compared to most other common stereo driver layouts. Thanks to the 3rd driver at the front the speaker doesn't have to rely solely on the side-drivers which usually would get a bit lost as they emit away from the listener, but the 3rd driver provides a solid base at the speaker front and offers the main unbiased sound source with the side drivers adding rather a kind of additional stereo-ambience. The side drivers do not play the full left or right channel respectively, but seem to rather play some kind of difference between each stereo channels, while the front driver could be the sum of both channels. Of course I have no clue what kind of processing is really going on here, but it seems pretty effective as the sound stage of the Turbo X is really opened up and gives you a distinct sense for left/right, although you shouldn't expect any magic, it is better than most other speakers, but when listening to the Turbo X and the Denon Envaya Mini side by side, I even found the Denon to offer a more convincing stereo image with an even broader separation, although not without some negative side effects thanks to the used psychoacoustic stereo broadening algorithms, which are completely missing in case of the Turbo X.
To shed some light on the magic behind Trillium I tried performing some awkward measurements of the separate drivers, which I will share later.

How does the Turbo X sound? First let me confess that at the very beginning it didn't blow me away. The first time I tried the Turbo X I was at home with my family and I could only turn it up some notches to realize that the sound had a bit of a tinny character, at least for my personal taste. I immediately included the Denon Envaya Mini into my test and started switching between both with the Denon definitely having a fuller bodied sound at these levels, it sounded more airy, more profound without having any bloated or unnatural character like the Bose Soundlink Mini, but the Denon nevertheless managed to sound bigger, bigger than the 4 times as big Turbo X. But then my first impression reversed nearly completely as soon as I started turning up the Turbo X to higher levels suddenly the sound gained the low frequency range I initially expected and hoped for from the very beginning. At levels close to maximum the RIVA Turbo X simply outperformed most other portable speakers I have heard so far, which usually start to reduce bass from some point on, sometimes even close to half of their volume range like the B&O Beoplay A2 for example which pretends to sound like a huge speaker if you keep the volume below half, but dare turning it higher.. The Turbo X on the other hand remains restrained without any compression any bass reduction or stronger distortion. The louder I turned it the better it sounded. Maximum volume without Turbo mode is not ear-splitting high, it is about similar to the loudness a JBL Charge 2 can reach, but while the JBL will already sound extremely compressed with little bass left, the RIVA Turbo X will rather sound like a big speaker. If this loudness is not enough for your needs, then there is still this infamous "Turbo-mode" which pumps up the volume some 7dB more when activated. Within the app, the volume dial will suddenly "go to eleven", a nice reference to Spinal Tap. With Turbo enabled RIVA Turbo X is louder than most other speakers in this class I have heard, including the B&O Beoplay A2, Bose Soundlink III, the Infinity One, TDK A33 etc, but still sounding equally profound and heavy as without Turbo. Both Beoplay A2 and Soundlink III might give a thick impression at low levels and make the Turbo X sound a bit lost but start cranking them a little higher and they will begin to sound coarse, hollow with all the bass drowned and compressed away. The only comparable speaker I have heard that is still quite a bit louder is the Beats Pill XL, but the Pill XL reduces bass and pushes mid-frequencies during its last volume notches too and starts sounding pretty forced and unpleasant due to the harsh mids that become dominating, not even mentioning the generally awkward Beats tuning for the Pill XL with some unexplainable upper-bass boost and biting treble. Although the IK Multimedia iLoud sounds much more natural than the Pill XL and might be louder as well it distorts heavily at highest levels, this together with the farting bassreflex port makes it hardly louder than the Turbo X when distortionfree sound is wanted.

I took the the RIVA Turbo X to a store and tested it against some other comparable speakers that I currently don't have at home like the Philips Shoqbox XL, UE Megaboom, House of Marley Get Together, etc. I turned them all to the maximum and switched back and forth between all of them, before they finally threw me out of the store, but the Turbo X blew them all away in power, loudness or simply quality of sound. The only speaker which performed considerably better and achieved a higher loudness was the Marshall Acton, but being more than twice the size and not portable at all puts the Marshall out of contest a bit. While even cheaper I found the Harman Kardon Onyx Studio to outperform the RIVA Turbo X as well, but I wouldn't regard the Onyx Studio as that portable, not to mention its battery life which is not even close to that of the Turbo X. One has also to remember that the Onyx Studio doesn't manage to keep up the sound quality and loudness when run from its internal battery. From battery both Onyx Studio and RIVA Turbo X will reach about the same maximum volume with the Onyx Studio distorting even slightly more, but having a deeper bass at the same time, still quite impressive for the Turbo X which is much more compact and easier to be taken around.
For all the loudness junkies out there I think the RIVA Turbo X should satisfy all needs, someone claiming it not being loud enough must be either deaf or have completely screwed up expectations of what is realistic at this size. It surely won't fill an entire football field, but you can definitely annoy your neighbours if taken outside into the garden, without even having to turn on "Turbo".
Many will probably ask if a Bose Sounddock Portable is still louder? Yes it is louder, but only because Bose applies extremely aggressive compression at even higher levels and forces the drivers to produce a high amount of distortion at the same time. When the Turbo X is playing at its maximum volume, the Bose will still play without any obvious processing and both will sound pretty similar in overall impact, but turn the Bose higher and the only thing it does is reducing bass and adding compression, it will not become really louder at all. I am sure the RIVA could be also forced to play louder, but this would lead to an obviously overprocessed sound.
I was asking myself when will I actually need this kind of high loudness at all. At home when with my family I cannot even turn the Turbo X to half without getting scolded. But when I tested the Turbo X against the B&O Beoplay A2 in the large listening room of the B&O store surprisingly I had to crank the speakers close to maximum to achieve an acceptable listening loudness. The same goes for outdoor listening: when out with some friends at the lake or in the park with the intention of playing some tunes, you will be probably close to "11" most of the time, otherwise you simply won't get this experience that music is catching you. Of course it is another story if you just want some background music at your office without disturbing your coworkers. In this case even "1" might be too loud then.

According to ADX and RIVA there is no additional processing at all going on in the background of the Turbo X sound engine with exception of the Trillium upmix. There is no limiter, no compressor nor any dynamic EQ etc. Only when "Turbo" is active some smart bass-compressor comes into play which in reality still remains hardly noticable. With "Turbo" you can hear some faint bass reduction, but the levels are already that loud, that bass amount is pretty high to begin with. The good thing is that there is no noticeable dynamic compression going on at all and music still contains all its dynamics with all peaks intact.
While you will usually want to crank volume higher when your favorite song is currently playing, with most other speakers this will end in a rather frustrating experience. It is interesting to compare how other similar speakers handle such high levels, with the best example being the Soundlink III which will sound much more bloated at low levels, but will start to sound funny at higher levels rather resembling an edgy kitchen-radio. The same goes for the Infinity One which can already suffer from considerable intermodulation distortion with many bass heavier tracks at half volume only to start reducing bass and add dynamic compression at higher levels which will result in a sound similar to a stuffed sausage which you can hear from my first quick soundcheck I did of both:

Talking about distortion and intermodulation, I didn't notice any on the Turbo X. It remained restrained with even the most demanding tracks, the drivers are extremely well under control and are never pushed over their limits. The only distortion I noticed was on quite heavy mastered modern stuff like the mixes from Soulpersona and particularly on stronger peaks of bassdrums etc. Normally you shouldn't hear any problems with all-time classic reference recordings from Steely Dan, Crusaders or whatever, but play some modern R&B or House-tunes, and some distortion might creep in at higher levels close to maximum. RIVA stresses that the Turbo X is all about natural sound reproduction, thus they don't seem to apply any limiter algorithms at all especially not when Turbo isn't active, therefore stronger peaks can cause strain to the drivers. The same songs played through the Infinity One may remain even distortionfree, but the bassdrums will be missing all the impact due to overly processed dynamics and they will have no bass at all, as most bass was dialed away.
If you encounter distortion on some tracks with the Turbo X and Turbo-mode being inactive, it will definitely help to activate Turbo and reduce volume to the same level as before (2-3 notches). With this trick you may notice some very slight bass reduction (which is the effect of the added bass compressor and some kind of EQ) but at the same time the issues should be completely gone. You should keep in mind that at such high levels you will hardly listen to the speaker from 1 meter away, and from some distance any slight squalidness will diminish anyway. I just found that if high volume was my main goal I preferred activating Turbo mode by default, even if I didn't reach quite the "11" Turbo usually offers, but this way I could push the distortionfree level quite a bit higher, than if I played the Turbo X without activating Turbo. Apart from the high-volume benefit so far Turbo-mode doesn't really seem to do much to the sound at lower levels, the sound appears just louder than without Turbo, I cannot discern any other impact on sound including any bass-reduction, on the contrary I think that Turbo at low levels tends to push bass slightly to the foreground, probably as a side-effect of the bass-compressor. I would willingly leave Turbo on by default but unfortunately you have to activate it every time you turn the speaker on as it doesn't remember the Turbo setting.

In future RIVA might even add some different tuning by applying a form of loudness compensation which the Turbo-mode could offer at lower levels although it rather seems that RIVA's philosophy is to get the most natural and unprocessed sound reproduction. They could have definitely tuned the Turbo X to sound like an Infinity One or a Bose Soundlink III at low levels, with the difference that the Turbo X would still sound better at high levels. Their drivers simply seem to be more sophisticated, more powerful or both. Nevertheless I am pretty sure that many would also welcome some bass-boost at lower levels to compensate for equal-loudness contours of the human hearing. Also when outdoor usage is intended without the need of turning the speaker to the maximum, the Turbo X should gain a bit of bass boost thanks to some revised Turbo-function, as outdoors most low frequency energy gets lost much faster than indoors due to missing room resonance etc. For any audiophile Hifi-connoisseur who demands unprocessed rendition "Turbo" could be simply kept off all the time, but for all us "bassheads" a Turbo bass boost would definitely satisfy our needs.
To give you an idea how the RIVA Turbo X performs at different loudness levels, I prepared a direct comparison against the Bose Soundlink Mini, which is much smaller but at the same time sounds much heavier than the Turbo X when listened at low levels, some would call it "boomy" maybe. The Bose cannot quite keep up this level and falls apart completely at its top volume, but I think a little low frequency boost at low levels would help the Turbo X to really shine here too as put against the Bose now it gives a rather lost impression. Thus for low volume background listening alone I would probably choose something else, in my case I indeed prefer the Denon Envaya Mini over the Bose for such a low-level scenario:

You can see from the measurements (nearfield measuring of the front driver smoothed with 1/12 octave) that I took for each available volume-step of the Turbo X that the sound remains always the same, there is no bass reduction at all with only the 3 red upper curves which represent the Turbo-mode showing a bit of a bass-loss, but in reality this loss is insignificant compared to how most other portable speakers are trying to cheat at high levels:

The general sound-tuning of the Turbo X is pretty neutral, it is definitely what I would call "true", because is not trying to add any "effect" that is not present in the original recording, it rather resembles a studiomonitor than a Hifi-speaker, which is usually tuned to sound "good". The Turbo X is missing any particular sound signature, many other brands tend to establish for their own products, therefore it is not sounding like a JBL nor like a Bose etc. When I compared the Turbo X to the B&O Beoplay A2 at levels where the A2 still could keep up, the Turbo X definitely sounded more natural. Although the A2 had deeper reaching bass and much sharper treble rendition, the Turbo X was simply more faithful to the original recording while the A2 was relying on its special EFX to gain some more attention, but the overall sound was coloured and far from flat.
There are little sound colorations to be heard from Turbo X too though, thus the sound is not completely flat. There is a minor emphasis in the presence region above 3kHz but apart from that it measures and sounds very natural. Bass is tight without any obvious boost but it doesn't reach overly deep as it already starts dropping below 70Hz, reaching 64Hz at -3dB, which is in line with most other comparable speakers, just that the Turbo X manages to keep this bass level up to maximum volume. So don't expect any subwoofer-effects, the bass is definitely punchy and tight at the same time, as long as you keep the level at higher steps, but the Turbo X is not what I would call a bassheavy speaker, like many other boomboxes around, which tend to overemphasize the entire low-frequency spectrum. Don't expect that from the Turbo X as it sounds rather neutral.
Just for comparison and to demonstrate the effects of adaptive equalization, I made an overlay of both measurements for the Turbo X in black and the Denon Envaya Mini in green at 3 different loudness levels (unsmoothed). The first curve at the bottom corresponds to volume step 30/100 of the Denon, which is a pretty low volume in reality. The center curve is 40/100 and the upper curve is 67/100 with the Turbo X matched respectively. You can see that at low levels the Denon will obviously sound fuller but already above Denon's half volume the Turbo X is passing by because the Denon will start reducing its entire low frequency response.

The only thing I am personally missing is some sparkle from the upper treble region. The Turbo X does never sound dull per se, as the presence region is well defined and while many similar portable speakers relying just on fullrange drivers usually start rolling-off above 14-16kHz the Turbo X has already some slight roll-off starting at 9kHz with a stronger drop above 14kHz. The overall treble rendition of the Turbo X reminds me a bit of the Bose Soundlink Mini which is simply missing all the highest frequencies but has some boosted lower treble at the same time to compensate for that, it's only that Bose exaggerates with its frequency boosts, while the Turbo X manages to keep the overall response still rather neutral. The Turbo X does not sound muffled but it is definitely not a bright sounding speaker either like the Beoplay A2 for example, if you are a fan of ribbon tweeters and the most detailed sound rendition, you might be disappointed with the Turbo X.
To make the overall sound judgement even more difficult you can include the side drivers as well, which seem to have a different frequency response than the main driver. I first noticed that from my listening tests, which later got confirmed from my measurings.
The side drivers have the high frequency response boosted quite a bit compared to the main front driver. This boost might be just there to compensate for the sound emission that goes rather sidewards, or might be a result of the Trillium processing, but I definitely prefer the clearer sound the side drivers are producing than the main driver is able to offer. Here you can see a difference of both the front driver and the left driver. The overall response of the left (and right) driver depends a lot on the signal it is getting or rather the difference between the left and right stereo channel. If fed with a simple mono signal, the side drivers are not producing any higher-frequencies, which you can see from the green curve. The black curve represents the front driver, which measures always the same, regardless if it gets a left/right only or a mono-signal, but as you can see the frequency response of the side drivers changes, depending if they are fed with a left or a right signal. Red is the left driver fed with a right signal and blue the left driver fed with a left signal. I won't analyze this in detail, as I have no clue what kind of processing is going on here exactly, but I think the measurements show the extended and slightly boosted high frequency response of the side drivers compared to the main driver, which rolls-off a bit too steep above 9kHz.

The huge benefit of the side drivers is not only an increased stereo image but also much wider sound dispersion. The Turbo X will not only sound good from the sides but can even sound convincing from slightly behind as you will still hear one of the side-drivers adding enough to the sound to remain consistent. This makes the Turbo X much less directional than most other speakers. It is not a full 360° experience, but the sound dispersion is nevertheless pretty wide. I also found that vertical directivity is not that extreme. Due to the fact that upper treble is slightly recessed to begin with, the response doesn't change much if not listened exactly at ear height. Of course the Turbo X will sound best when aimed directly at the listener, but treble loss is not substantial if the speaker is placed below or above as you can see from the following graph with the 45° off-axis measurement taken from above shown in pink compared to the on-axis measurement:

I prepared a comparison video where I put the Turbo X against the Libratone Zipp which is claimed to be a 360° omnidirectional speaker. Both speakers were playing slightly below their maximum volume. The Libratone Zipp would play even quite a bit louder than the Turbo X, but it already distorts heavily at the shown loudness level, while the Turbo X remains perfectly clean without any hint of distortion. You will probably notice the strange honky sound characteristics of the Libratone Zipp, which makes many instruments sound different than in reality, although the RIVA Turbo X on the other hand could get along with a bit more upper treble brilliance for my taste:

I rather omitted the "Surround"-mode so far but would like to describe it here as well of course.
Surround is rather intended for movies, games etc. It doesn't seem to give good effects with music, especially not on music with lots of hard attacks. It might work better with orchestral and classical music. But from what I heard surround is an additional short cross-delay of some milliseconds between the left and right driver, this adds a bit of ambience to the sound and as the delay is in cross between both channels it broadens up the sound considerably but with the side effect that you can hear an additional echo with drum sounds etc. for example.

Here you can find another outdoor video which should give you an idea about the loudness the RIVA Turbo X is able to achieve compared to the JBL Charge 2 and Infinity One. At the end of the video you can also find a test of the Bluetooth range between both:

Of course I will add the RIVA Turbo X to my upcoming audio database, which will allow you to compare it to any other speaker included in the list. Please give me some more time to finish everything as there are still some things to be sorted out.

Concluding I must say that I am quite impressed with RIVA's first product. It is interesting that is has to take a completely new an unknown company to finally produce a speaker that apparently fares better than most other products from such huge and well established companies like B&W, B&O, JBL etc. The Turbo X shows its full potential at high levels and manages to outperform the entire competition. It is not cheap for sure but definitely worth it, if you compare what B&W dare to charge for their "micromatrix"...
The Turbo X is a speaker which will make more fun the higher you turn it. At maximum volume there might be some slight distortion with bass heavy recordings, but reduce volume by one notch and it should be gone. Most other portable speakers I have tried so far start compromising their sound from a particular volume level upwards by applying lots of dynamics compression, bass reduction while still producing enough distortion to make them unenjoyable to listen to if high loudness is really intended. The Turbo X sounds very natural without any obvious frequency boosts which any audiophile music lover will definitely appreciate although it is missing quite a bit of the upper treble sparkle many other speakers may offer, this is the only complaint I have. It does not sound dull, but highest frequencies are subdued a little bit. The other drawback is that if you like a full bodied and heavy sound at low levels as well, unfortunately the Turbo X won't satisfy as it doesn't apply any kind of low-volume bassboost or loudness compensation like some other speakers. A Bose Soundlink Mini, or even a smaller Denon Envaya Mini both manage a warmer and more punchy sound at low levels, the Turbo X really only starts shining when all the other speakers are already suffering and closer to their limits. ADX's own patented Trillium technology makes the sound not only extend beyond the speaker-borders but allows for an overall better sound dispersion off-axis as well. The Turbo X does not need to be listened exactly on axis only like so many other speakers but can also be heard from wider angles and even from slightly behind thanks to the side-drivers. What you get is a close to 360° listening experience, maybe even better than the Megaboom as this one suffers considerably if not one of the two drivers is facing you directly.
Other points that make the RIVA Turbo X stand out is the examplary battery life that lets you achieve 6 hours at full blast without any loss in quality or loudness, and let me tell you that full volume with Turbo mode enabled is really loud and blows away any of the other Megaboom-junk or similar wannabe speakers, but keep in mind that the RIVA Turbo X is not just some stupid Boombox with a forced smiley-response, it really sounds true to the original sound and does not try to give you any artificial bass effect pretending to reach lower than it actually does.
The design and glossy finish might not be perfect for heavy duty outdoor usage, but the Turbo X gives nevertheless a pretty sturdy impression and is weather resistant as well. Just be sure to get the additional transport bag from RIVA to protect it against scratches. The RIVA Turbo X gets my strong reccomendation for anyone who is longing for a real high performance portable speaker that is still compact but without having to make any compromises on sound or loudness. The Turbo X should be able to power any party, especially if you are a DJ and want to put the needle on your records, the Turbo X is definitely the way to go!

+ stylish understated design
+ weather resistant
+ natural unbiased sound rendition
+ louder than most competition
+ no bass reduction, no compression even at max. volume
+ no intermodulation distortion up to highest levels
+ great stereo separation
+ very wide sound dispersion
+ own surround mode gives additional ambience to movies, games etc.
+ app support for iOS and Android devices
+ volume control mirrored between speaker, iPhone and app
+ logarithmic volume curve allows sensitive control at lower levels
+ high bluetooth reach with aptX support

+ phono mode for all vinyl-lovers
+ exemplary battery life
+ quick recharging
+ charging of external devices
+ data port for future updates

- scratch sensitive glossy finish
- status tones too loud, cannot be turned off completely
- slight distortion on bassheavy recordings at max. volume (with Turbo on or off)
- sound a bit unimpressive at low levels
- lacks upper treble definition
- bass could reach lower although in-line with most competition
- some slight bugs within app or volume control of the speaker
- strong self discharge in standby-mode
- carrying bag only as extra
- expensive