January 2012 Archives

The digiZoid ZO

digiZoid ZO 2.3

After a month of wait­ing for them to get more sup­ply, I fi­nally re­ceived my di­gi­Zoid ZO 2.3. The box calls it a "per­sonal sub­woofer" which sounds en­tirely ridicu­lous, but think­ing about it I can't seem to come up with any bet­ter tagline my­self.

The ZO is a $100 head­phone amp, which di­gi­Zoid says is ca­pa­ble of dri­ving cans up to a fairly de­mand­ing 300Ω. Its main claim to fame, how­ever, is a unique bass-boost­ing tech­nol­ogy they call SmartVek­tor. Not your dad's one-note bass-boost­ing EQ, SmartVek­tor adds an ad­dic­tive warmth and pre­serves tex­ture while bring­ing even the slight­est hint of bass into the fore­ground.

The device

Op­er­at­ing the ZO is pretty sim­ple, hav­ing a large LED bar on the front, a multi-func­tion rocker on one side, and a Mini USB port on the other side for charg­ing. The case has a nice soft rub­ber­ized feel, though it looks a bit cheaply built.

With 32 con­tour lev­els, the ZO al­lows you to fine-tune the bass boost for your cans, music, and tastes. Con­trolled by the rocker, the front LED fades from green to red as the level in­creases. The low­est con­tour is nearly trans­par­ent, just barely warm­ing and rolling off around 30Hz. A few lev­els up at a yel­low-green color and the boost be­comes un­de­ni­able and with­out any rolloff. At red the boost has such an in­ten­sity that even the biggest bass-heads might find it too strong.

While di­gi­Zoid did put some ef­fort into mak­ing the con­tour lev­els per­cep­tu­ally lin­ear in the ZO 2, it's still not quite there. The ma­jor­ity of the boost­ing still hap­pens in the first half of lev­els, with the dif­fer­ence be­tween or­ange and red being very small.

Also pre­sent are low- and high-gain modes, con­fig­urable by press­ing the side but­ton once the ZO is turned on. Some have men­tioned they can hear a dif­fer­ence (other than vol­ume) be­tween low- and high- gain modes, but I haven't been able to de­tect any.

In­tended for usage with line-out, the low-gain mode al­lows you to at­ten­u­ate the vol­ume with a 32-level dig­i­tal vol­ume con­trol. Again, the vol­ume con­trol doesn't seem to be per­cep­tu­ally lin­ear ei­ther—at about 8 steps in it's al­ready quite high, and will slowly get about 2x louder in the re­main­ing 24 steps. The LED in­di­ca­tor also re­flects this, not ap­ply­ing the ~2.2 gamma re­quired to lin­earize it for human vi­sion.

Once the vol­ume is as high as it can go, the LED will turn pur­ple. Hold­ing down the rocker for sev­eral more sec­onds will turn the LED pink, ac­ti­vat­ing high-gain mode. In­tended for use with head­phone-out, high-gain mode lacks any vol­ume con­trol but will give a very sig­nif­i­cant boost to vol­ume.

The ZO's max­i­mum input is 250 mVrms in high-gain mode and 1 Vrms in low-gain mode, mean­ing it is fairly easy to over­load it with a stan­dard 2 Vrms line-out such as the one on my sound card. di­gi­Zoid rec­om­mends start­ing with your source vol­ume at 25% and in­creas­ing the ZO and then the source's vol­ume until it's at ac­cept­able lev­els.

The box con­tains two 3.5mm male to male ca­bles, one six inch and one three foot. They are per­haps the cheap­est look­ing ca­bles I've ever seen, but I sus­pect any­one who cares will al­ready have some badass $200 cryo-treated cable of their own. To me, the six inch one is great for portable use.

One of the first is­sues I no­ticed while using the ZO is that one of the chan­nels will some­times (very rarely) cut out until you fid­dle around with the cable. This ap­pears to be an issue with the de­vice it­self, from the jack being slightly re­cessed and thus hav­ing a poor con­tact area with some ca­bles. The ca­bles in­cluded with the ZO have a small ring that fits the re­cessed area per­fectly, and thus far have not ex­hib­ited the prob­lem.

This is the fourth re­vi­sion of the ZO. After being ig­nored for some time, the first began get­ting a lot of no­tice by audio fo­rums like Head-Fi, which di­gi­Zoid was quick to join. After tak­ing a lot of input from the com­mu­nity the ZO 2 was un­leashed with a by­pass mode, re­moved loud pops when you turned it on, and per­cep­tu­ally lin­ear con­tour lev­els to allow much more fine-grained tun­ing at lower lev­els. The ZO 2.2 cor­rected hiss­ing prob­lems with IEMs and vol­ume prob­lems with line-out. The most re­cent re­vi­sion, the 2.3, re­moved by­pass func­tion­al­ity and added sep­a­rate low- and high-gain modes to fur­ther cor­rect prob­lems with line-out.

In­cred­i­bly upon dis­cov­er­ing is­sues with the pre­vi­ous re­vi­sions, di­gi­Zoid of­fered to re­place vir­tu­ally every ZO 2 with a 2.2, and then again every 2.2 with a 2.3. I've never seen this kind of above-and-be­yond de­vo­tion to prod­uct qual­ity and cus­tomer sat­is­fac­tion be­fore, es­pe­cially with a de­vice they're charg­ing $100 for. This was ac­tu­ally one of the big­ger fac­tors that con­vinced me to take the plunge and get a ZO.

For how big of a punch it packs, the ZO is sur­pris­ingly tiny and portable. Here it is com­pared to—from left to right—the Pen­guinAmp Royal, Cowon D2, and in case you've never seen ei­ther of those, a credit card.

PenguinAmp Royal, Cowon D2, credit card, and ZO size comparison

As far as test­ing goes, I've got sev­eral sides of the spec­trum cov­ered: the Bey­er­dy­namic DT-770 Pro 80Ω, Su­per­lux HD-668b, AKG K81 DJ, Etymōtic ER-6i IEMs, and Log­itech Z-5300 speak­ers. For my sources I'm using a Cowon D2 (with D2+ firmware) for high gain mode and the line-out on an Asus Xonar D2 for low gain mode. I've been able to give it a good run lis­ten­ing to a va­ri­ety of film scores, techno, and rock.

SmartVektor

Sim­i­lar to BBE's Mach 3 Bass, SmartVek­tor is more than a sim­ple low-freq EQ. De­signed to process a purely ana­log sig­nal, SmartVek­tor will eas­ily in­te­grate with pretty much any dumb audio sys­tem. For now it ex­ists solely in the ZO, but di­gi­Zoid hopes to bring the tech­nol­ogy into other less niche sys­tems much like BBE has done.

De­scribed in US patent ap­pli­ca­tion 20090290728, "DY­NAMIC CON­TOURED-SOUND/SUB­WOOFER-SYN­THE­SIS AUDIO SYS­TEM", SmartVek­tor at­tempts to com­pen­sate for both the human au­di­tory sys­tem and the fre­quency re­sponse typ­i­cal in speak­ers. Though the ZO cur­rently only boosts bass, SmartVek­tor is also ca­pa­ble of op­er­at­ing on tre­ble.

The sound of SmartVek­tor is a lit­tle dif­fi­cult to de­scribe. It seems to pull out de­tail that nor­mally re­mains hid­den deep in the bass, bring­ing it into the fore­ground for a rich, warm, tex­tured ex­pe­ri­ence that you'd nor­mally only get with pow­er­ful speak­ers cranked to 11 and a ded­i­cated sub­woofer.

On ini­tial use it was easy to set the con­tour level to yel­low-or­ange and for­get the ZO was even con­nected. After re­al­iz­ing this, I'd con­stantly turn it down to green to see if it was ac­tu­ally doing any­thing. Like night and day, turned down the music just de­flates and be­comes life­less.

More often than not it sim­ply makes music sound bet­ter and most im­por­tantly, nat­ural. Using it doesn't feel dirty or dis­re­spect­ful to all the hard work artists put into the cre­ation of the music.

RMAA

This is the first time I've used RMAA, but I be­lieve I did every­thing right. (Well, as right as it can be.)

All test­ing was done from my Xonar D2's line-out into the line-in with a 75Ω load at 24-bit and 48kHz. Un­for­tu­nately RMAA con­tin­ued to ei­ther crash or not pick up any sig­nal every sin­gle time I plugged in my Cowon D2 to test BBE's Mach 3 Bass. If any­one knows what would cause that, please let me know!

Frequency response at low contours

Here you can see the ZO's ini­tial con­tour lev­els. A green level (con­tour 1 on the graph) is very nearly trans­par­ent, with a rolloff be­gin­ning at around 90Hz and pass­ing below 0dB at around 40Hz. At yel­low-green (con­tour 4) the boost is a very au­di­ble 4dB with a rolloff be­gin­ning at around 50Hz. With rolloffs still well within the au­di­ble range, it's pos­si­ble that some will be able to no­tice it de­pend­ing on how low their setup can re­pro­duce.

Frequency response at high contours

At a yel­low con­tour (8 on the graph) the boost reaches around 6dB with a rolloff be­gin­ning around 40Hz. At this point the rolloff should be nearly in­audi­ble. Per­haps co­in­ci­den­tally, this is the level I pre­ferred most of my music at. At or­ange (con­tour 16), it hits around a 9dB boost. At it's high­est con­tour (red), the boost reaches just around 13dB.

Low- and high-gain comparison

Some have men­tioned hear­ing a dif­fer­ence be­tween low- and high-gain modes. My tests here show them to be iden­ti­cal, so I'd be cu­ri­ous to know what se­tups peo­ple are using that let them hear a dif­fer­ence.

Comparison with the PenguinAmp Royal

And fi­nally we have a com­par­i­son be­tween the Pen­guinAmp Royal's high­est bass boost and the ZO's high­est con­tour. The Pen­guinAmp peaks at 14dB—just a smidge above the ZO—and has no au­di­ble rolloff.

De­spite boost­ing by sim­i­lar lev­els on paper, the ZO ac­tu­ally sounds much louder due to its peak being about 15Hz higher. This cre­ates a ~3dB gap at fre­quen­cies which are both eas­ier to hear and eas­ier to re­pro­duce. The ZO sounds far more de­tailed as well, which con­tributes sig­nif­i­cantly more than sim­ple in­ten­sity.

Beyerdynamic DT-770 Pro 80Ω

Beyerdynamic DT-770 Pro 80Ω

The Bey­er­dy­namic DT-770 Pro 80Ω are bass-heavy cans. Prop­erly paired with an amp the bass be­comes very tight and tex­tured, with a pref­er­ence to­ward deep bass keep­ing them punchy with­out mud­dy­ing up any­thing.

The ZO has no prob­lem dri­ving these 80Ω/96dB­SPL cans, with no noise to speak of. Kept be­tween green and yel­low, this com­bi­na­tion pro­vides mind-numb­ing bass that I'm com­fort­able lis­ten­ing to for hours. Bring it up to­wards or­ange and bass will be­come far too heavy, and with some songs even causes dis­tor­tion as the dri­vers begin to run out of ex­cur­sion.

I wasn't sure how the ZO would sound with al­ready bass-heavy head­phones, but it turned out to be pretty damn good. Kept to low con­tours, the ZO adds a lot of tex­ture and warmth with­out di­min­ish­ing other qual­i­ties.

Superlux HD-668b

Superlux HD-668b

Mon­i­tors in every sense of the word, the Su­per­lux HD-668b are very an­a­lyt­i­cal, with im­pres­sively crys­tal-clear mids and highs and a very muted bass re­sponse.

These have the least amount of bass I've heard from any full-sized head­phones, so to me they were the real test for the ZO's magic. Thus far, I've not heard a sin­gle bass boost which could make these cans thump. Again the ZO had no prob­lem dri­ving these 56Ω/98dB­SPL cans, with no au­di­ble noise. Every­thing from yel­low all the way up to red works won­der­fully with­out any dis­tor­tion.

While not nearly as in­tense as the DT-770s, the ZO does give these a re­spectable amount of tight, de­tailed bass. These re­ally are ex­cel­lent sound­ing head­phones for the price, and adding the ZO rounds them out very nicely.

AKG K81 DJ

AKG K81 DJ

The AKG K81 DJ are bass-heavy and a tiny bit warm, with slightly rolled off highs.

The ZO drove these sen­si­tive 32Ω/100dB­SPL cans well, again with­out any au­di­ble noise. A green-yel­low con­tour level is the sweet spot, with bass be­com­ing far too strong around or­ange. For those want­ing to clean some wax out of their ears, the ZO works all the way to red with­out any dis­tor­tion, even at high vol­umes.

The K81 DJs aleady have a lot of bass to offer, but the ZO helps tighten it up and adds a lot of de­tail. If you can han­dle the head­band's squeeze of death, the ZO and the K81 DJ will make a very good pair when porta­bil­ity is re­quired.

Etymōtic ER-6i

Etymōtic ER-6i

The Etymōtic ER-6i are cold and an­a­lyt­i­cal, with fan­tas­tic mids and highs. Typ­i­cal of af­ford­able bal­anced ar­ma­ture IEMs and prob­a­bly moreso than most, there is no bass to speak of.

At 16Ω/110dB­SPL, these are very sen­si­tive and will usu­ally pick up any flaws in what they're plugged in to. Un­for­tu­nately, there is a lot to pick up with the ZO. There's an au­di­ble hiss—in­de­pen­dent of vol­ume, gain mode, and con­tour level—which is very not­i­ca­ble in quiet parts. In com­par­i­son, it has around 3x the hiss of my Asus Xonar D2, and 2x the hiss of my Cowon D2. An­other noise, less of an issue, is an only slightly au­di­ble click every time the vol­ume is ad­justed in low-gain mode.

Using a re­sis­tor adapter does alter the sound slightly, but is well worth it as it will quiet all the hiss. A 32Ω adapter would prob­a­bly be plenty, but I've only got a 75Ω one and the ZO has plenty of power to spare.

Even mov­ing all the way up to red, the ZO pro­vides next to no bass—I sus­pect these IEMs just aren't phys­i­cally ca­pa­ble of it. Don't let that dis­cour­age you though, be­cause it does sig­nif­i­cantly im­prove the ex­pe­ri­ence by adding a huge amount of warmth. If your music doesn't have a lot of dy­namic range or if you have a re­sis­tor adapter, I can def­i­nitely rec­om­mend the ZO for thaw­ing out these im­pos­si­bly cold IEMs.

Logitech Z-5300

Logitech Z-5300

The Log­itech Z-5300 are def­i­nitely not au­dio­phile-grade speak­ers. De­signed for mid-range 5.1 gam­ing, they're warm, very heavy on the bass, and not super ac­cu­rate.

I've had them for nearly 10 years and they've done the job well enough both for the paint-chip­ping thud of an AWP going off in Counter-Strike and fol­low­ing my evo­lu­tion through the overly-loud mus­ings of a teenager's pop­u­lar rap and rock, a soft­ware pro­gram­mer's thump­ing techno, and fi­nally into more re­fined film scores and indie rock.

Given SmartVek­tor's claim of cor­rect­ing for the fre­quency re­sponse in speak­ers, I wasn't sure what to ex­pect when paired with a 6.5" 100W (RMS) sub. Un­like head­phones, I didn't no­tice much more tex­ture in the bass—it ap­pears the sub was al­ready doing that plenty well on its own. It did, how­ever, be­come much deeper and cer­tainly more pow­er­ful. The satel­lites did be­come warmer and bassier, but only slightly.

The sweet spot to me was a con­tour level of yel­low, though the ZO was able to func­tion fine from green all the way to an in­toller­a­ble red with no au­di­ble dis­tor­tion or noise. The sys­tem al­ready had plenty of bass for me so I don't think I'll be pair­ing the ZO with it in the fu­ture.

Music

Over­all the ZO seems to work great with pretty much any pop­u­lar music. The de­vice does un­for­tu­nately shrink the sound­stage, so music with a lot of bassy in­stru­ments may be­come a bit muddy if used at a high con­tour level.

Film scores

Syn­the­sized '80s scores tend to sound re­ally fun. Jerry Gold­smith's Grem­lins and Bear Mc­Creary's '80s-in­spired Zom-B-Movie are awe­some. Sim­ple ac­tion music and eth­nic in­stru­ments also fair well—Greg Ed­mon­son's Un­charted 3 and Harry Greg­son-Williams' Prince of Per­sia: The Sands of Time both sound in­cred­i­ble.

Com­plex or­ches­tral arrange­ments with a lot of in­tru­ments are the ZO's down­fall, eas­ily be­com­ing muddy and los­ing sub­tle in­stru­ments while over-em­pha­siz­ing oth­ers. This seems to be very de­pen­dent on the cans, as my HD-668bs sounded far bet­ter than my DT770s here.

Rock

The ZO shines with rock. Korn's dub­step-in­fused The Path of To­tal­ity, Shiny Toy Guns' Sea­son of Poi­son, Nine Inch Nails' The Slip, and The Whigs' Mis­sion Con­trol all sounded wicked.

On the flip side, I no­ticed some bass gui­tars tend to be­come over-em­pha­sized. Un­like drums which stay punchy, the bass gui­tar quickly re­sults in muddy, over­bear­ing bass that risks swal­low­ing vo­cals and other gui­tars. Again, this is very de­pen­dent on the head­phones.

Techno

Techno works great, flat out. This is what the ZO was made for. Lis­ten­ing to Hadouken!'s For the Masses, Bass­nec­tar's Di­ver­gent Spec­trum, and all the DJs on afterhours.​fm, the ZO is the next best thing to being there live.

'nuff said.

The bottom line

The ZO is an amaz­ing, ad­dic­tive de­vice. The bass boost is hands down the best I've heard from any soft­ware or hard­ware-based so­lu­tion, bet­ter than BBE's Mach 3 Bass and eas­ily beat­ing out the Pen­guinAmp Royal. As far as an amp goes, I'd say the qual­ity is less than the Pen­guinAmp Royal but still far bet­ter than run­ning with no amp at all.

Pros
Cons
Wishlist

Was it worth the $100? Ab­solutely. Very highly rec­om­mended!