Dave Smith Instruments OB-6 Review – Part Three

Andy Jones concludes his review of the OB-6 with a look at it’s various other features…

Other Features
As with the Prophet-6 – and apologies for my continued references back to that synth, but it was a recent review and many of the features are understandably shared – you also get a great Unison Mode. This allows you to turn a six-voice poly synth into a great-sounding mono.


By that, I don’t mean it simply makes a mono synth with sounds stacked together – well it does, but it’s a bit more fully featured than that. Essentially, you can choose how many voices you stack – up to six. OB-6, like Prophet-6 (sorry), is at its best when you detune these parts in Unison Mode. By increasing the detuning between the oscillators – be subtle about this at first – you can create massive mono synth sounds, and I mean massive.

You can go a bit too bonkers here – especially when you bring the sub and noise in – but it’s a surprisingly usable feature. You may think you only want a poly synth, but when you hear what‘s possible here, you’ll understand the thinking behind it.

Within Unison Mode, there is also a Chord Memory function which stores the chord you play per note and transposes it up and down the keyboard as you play – useful for setting up chordal stabs.

Now we get to the two sections at the top of the OB-6 front panel, where we find the very useful Sequencer and Arpeggiator features. I didn’t really have the room to cover these in my Prophet-6 review, but both are fairly standard and easy to get your head around.

The Arpeggiator is linked to the Hold button (located nearer the keyboard) to latch the notes i.e. carry on playing your played chord even when you release the notes. This is great for making evolving sequences that move in real time according to edits made on the front panel – showing off, basically! You can easily sync clock sources or the internal delay effects, too – all good stuff.

The sequencer is a step sequencer comprising up to 64 steps, with up to six notes per step. You use it by hitting the Record button and recording step by step including Rests (gaps) if you need them, or Ties to extend notes. It’s more useful as a live song player so you can play along to it as a backing track (as long as you don’t exceed the six notes of polyphony in total). This (and the Arpeggiator) can be synced to an external audio source via an input socket, so you could play along to a drum machine, too.


Both the Arpeggiator and Sequencer really do extend what are already pretty good performance features on the OB-6. It’s much more a players’ synth than you might at first think – I certainly approached it as more of a sound creator than performer. Yes, it obviously has the elements for creating many great sounds; but in its modulation features plus the Sequencer and Arpeggiator, it has plenty of options and tools to manipulate, perform, record and play back live, too. Solo performers and players really can noodle away on it as much as they like.

We come to the final section of the synth, and this is the one that distinguishes OB-6 from many other analogues: digital effects! It is a dual effects engine (Effect A and B), so two can be stored per program. You get delays, chorusing, flangers, phasers and reverbs and the effects are placed in series with all reverbs on Effect B (as they would normally be placed in an effects chain).

Yes, the Prophet-6 has these effects, too, and they are broadly similar. However, the OB-6 also features a ring modulator and phase shifter modelled on classic Oberheim designs, the former offering a pleasingly gritty and metallic edge, and the latter rather more subtle phasing based on an Oberheim six-stage model.

Using the effects couldn’t be easier: simply select A or B, dial in your effect and then choose the Mix dial to blend each. You get two main parameters to adjust, which are usually the most commonly accessed ones for each effect (so you’ll find delay times and feedback for delays, and rates and depths for flangers).

As we’ve said, the delay effects can be synced to the Arpeggiator as well as an external MIDI clock and to the onboard Sequencer.

In use, the effects are gloriously simple to employ and incredibly clean, not surprising, given their digital nature – unless, that is, you layer distortion on there.

This is an effect that you access by holding down the Effect button, one that is always just a dial away and also one that’s been used so well on the more in-your-face presets.

But going back to the ‘digital subject’ and, for the analogue purists among you, bypassing the effects keeps the analogue signal of OB-6 completely digital-free. So if you don’t want this modern technology influencing your classic sound, you can switch off the evil magic at the touch of a button/dial.

To do that, though, you’d be missing out on a rather good feature on the OB-6, and a great and versatile weapon in its already well-stocked sonic armoury.

The Sound
The first thing to note about the OB-6 sound is that it is instant. As I found at the NAMM show, the presets quickly draw you into their lush world. There’s a lot of movement, a lot of grabbing, a lot of: ‘come on in and feel the noise’.

The Prophet-6 was a little less forthcoming; where that said: ‘you know what I’m capable of, I don’t need to shout about it’, the OB-6 is singing from every rooftop. My first pass through was halted on a number of occasions by sounds I simply got lost in. It happened as early as preset 7, a sound with a dreamy electric piano repeated so well that it almost becomes a pad, and a preset that added 20 minutes to this review’s time before I wrenched myself onwards.

Others just show off; you play what you think will be high notes at the upper register and then go for a low version and the whole sound swoops down to it, often demoing part of that X-Mod functionality.

There are some incredible pads – of course there are – some searing, gorgeous strings and organs. OB-6 also does squelch well; the 303, the bloody 303… And continuing on from that theme, this is a great dance synth: lots of bass, lots of movement, lots of ARP-ing… I used to be a little shy of US synths, thinking that they leaned a bit too much towards playing the intro to Van Halen’s Jump (played on an OB-Xa).

But while this can do that, and we’ve already seen it is a players’ synth, it also does big dance sounds well. The US has adopted dance big time, and it shows. Some of the presets that utilise the arpeggiator are simply stunning, too – press the Hold button on number 39, stand back, tweak the filter or resonance every so often and you could charge an entrance fee (some people back in the 90s did a lot less for a lot more, let me tell you!)

There’s inspiration and atmosphere around every corner, too. I normally take notes if I get any tune ideas as I play – and I filled a side of A4 in no time during this test. If the makers of Blade Runner 2 need a score, then I’m available to do it… with this synth, right? I even, and this has never happened before, left the studio to tell my wife how good OB-6 sounds (she looked at me with that ‘who the hell is he?’ expression again).

Negatives? Don’t play preset 22 – it’s a trumpet-thing; a ghastly effort, but pretty much the only blip on the OB. OK there are a few other duds – maybe I could have done with less of the percussive sounds and the odd simple, thin bass – but these are rare, and programming this synth is just so easy that I can quickly make it my own, with my own sounds, and I’m sure I will…

Must. Not. Mention. The. Prophet-6. Again. Oh, well. Yes, it’s got a different sound; yes, it has fewer effects – but you can’t deny that the Prophet-6 is a classic analogue synth with modern sensibilities, just like the OB-6.

And considering it currently weighs in at £300 less than the OB-6, I’d say it is an alternative (spend the £300 on a modular Oberheim filter!). Then there’s a new Oberheim, in the form of the Two Voice Pro, which Tom describes as his favourite synth and ‘very similar to the original, but with the addition of a few interesting upgrades’. That retails for $3,495.

Alternatively, well, there’s always software, but I can’t help thinking if you’re considering software then you probably wouldn’t have read nearly six pages of one review of a £2k+ analogue synth. Having said that, as I write this, Arturia is announcing an all new V-Collection 5 which has a whole bunch of classic synths in it (including Oberheim SEM and Prophet-5), for around £300.

Finally, we couldn’t not mention the SE SENSEI I reviewed last month, complete with Oberheim filter (and Minimoog, and ARP etc, etc). Not so much an alternative, more a great excuse to put a pic in the mag again!

I can’t avoid comparisons (and haven’t!) with the DSI Prophet-6, as so many of the features on the OB-6 are shared with that synth. X-Mod is Prophet-6’s Poly Mod in all but name, the Arpeggiator and Sequencer sections are identical, as are the Aftertouch, Mixer, LFO and other features.

But the heart of the OB-6 – its oscillators and filters – are Oberheim through and through, so the resulting overall character is different… it’s a bit like having a couple of children with very different personalities.

The differences? Well, if I have to put them side by side and call it (which I did in the test), I’d reiterate that the OB-6 is more in your face, perhaps more versatile, more dance, more electronica and less refined in some areas. It’s grittier and darker, but the Prophet has a class all of its own – maybe it leans slightly towards more classic sounds, whereas OB is more ballsy and new.

It’s tough to call, if I’m honest… However, what is obvious is that, like the Prophet-6, OB-6 is a classic reborn into very much a 21st-century synth, complete with many mod cons. So while the sound is different, feature-wise, there is little to separate them.

And, having given the Prophet-6 top marks, you can almost see where this one is heading. Having said that, I did nearly mark OB-6 down on the price, as the OB synth is currently listing at around £300 more than the Prophet-6 in the UK – which is significant. However, after listening to it, I fell for its OB charms, and wanted to return to them again and again. At every turn, it inspires new riffs and complete tunes and, when all is said and done, you can’t ask for more than that from any instrument.

Key Features

● 49-note, 6-voice analogue synth with velocity and aftertouch
● 500 user and 500 factory presets in 10 banks of 100 each
● Two VCOs/voice
● Cont. variable wave shape
● Osc 1 syncs to osc 2
● Square-wave sub (osc 1); LFO mode (osc 2)
● Mixer for osc 1, osc 2, sub and noise
● 2-pole resonant filter per voice
● Filter and Amp envelopes feature 4-stage ADSR with velocity modulation
● LFO with 5 waves
● Arpeggiator with up, down, up/down, random, and assign modes
● Polyphonic step sequencer with up to 64 steps, ties and rests
● Effects: stereo analogue distortion; 24-bit, 48 kHz digital effects: reverb, delay, chorus, flanger, phase shifters, ring modulator
● Effects bypass retains analogue signal path
● Connections: Left/mono and right 1/4” outs; h/p out; MIDI in, out & thru ports; USB MIDI; expression, sustain & volume ped. i/p; seq. start/stop f/s
● Dimensions (L x Wx H in mm): 807 x 323 x 117
● Weight (kg): 9.5