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Guitar Technology

Reviews, Tips and Techniques By Paul White & Matt Houghton
Published December 2008

Schertler DYN-G Acoustic Instrument Pickup

Schertler's DYN–G pickup is one of a range of surface–mounted dynamic pickups that plug straight into your desk's mic input, or into an acoustic instrument amplifier.Schertler's DYN–G pickup is one of a range of surface–mounted dynamic pickups that plug straight into your desk's mic input, or into an acoustic instrument amplifier.Swiss company Schertler make a range of instrument transducers, some of which are based on electrostatic designs, and others on dynamic principles. The DYN-G pickup that's reviewed here is dynamic, and it can be plugged directly into a balanced mic input, without any need for a separate preamp or phantom power. Although it was designed primarily for live use, it is also useful in studio recording applications when enhanced separation is necessary. The pickup is intended for guitar, but it's also suitable for most acoustic stringed instruments, including banjo and violin.

Physically, the DYN-G comprises a lightweight disc — which contains the transducer — connected by means of a thin, screened cable (around a metre in length) to a balanced XLR connector. This means that if you need to extend it, you can do so using a conventional mic cable. The DYN–G comes in a foam–lined wooden box with a tin of re-usable fixing–putty, which is something like extra sticky Blu–Tak (more about that in a moment).

This particular transducer picks up vibrations directly from the instrument's body via a small pad at the centre of the pickup. The putty is used to form a small, doughnut-like ring around the face of the pickup: this won't damage even the most fragile surface, but it sticks rather well as long as you remember to clean the instrument first, in this case by wiping the guitar surface using a rag damped with meths to remove any grease. In fact, I tried it on my friend's 1920s Gibson arch–top guitar and, try as we might, we couldn't pull any of the finish off! Any putty left behind on the surface can be removed by dabbing at it with another piece.

Fixing the pickup is no problem, although you may need to support the cable in some way to prevent it pulling the pickup off the guitar. The real skill comes in discovering where it sounds best: as with any contact pickup solution, the sound varies enormously across the instrument. On the guitars I tried, I found that I got the best results by placing the pickup about halfway between the bridge and the edge of the body, but you do need to experiment to find out what works best for you and the instrument in question. It's simplest to move the pickup around by hand while the instrument is being played — rather like using a stethoscope. Then, when the best place has been located, you apply the putty and stick it into place, making sure the centre pad is pressed right up against the surface of the soundboard.

Schertler's documentation reveals that the transducer has an essentially flat frequency response, which means that — as long as you find the best spot to mount it — you shouldn't need to use much EQ. They claim that the DYN pickups have better feedback performance than a conventional mic, but in reality any resonant instrument body will start to feed back at some level if a pickup is fitted. With the Gibson arch–top guitar fed into a small acoustic–guitar combo, feedback occurred at quite low levels — well below what you'd expect from an under-saddle piezo system — although, of course, while this may be an issue for some live applications, it's unlikely to pose any problems in the studio.

Tonally, the pickup delivered a warm and very full sound, emphasising the woodiness of the instrument, but as I'd expect with a contact mic, the direct zing of the strings didn't come through quite as well — so blending in a hint of piezo pickup with the bottom end rolled off might give an engineer more leeway in creating exactly the right sound. I got similar results using a larger flat–topped guitar: a very organic and full sound, with no piezo 'quack', but lacking just a little edge from the strings. Technically, although the signal was of a healthy level, it was very quiet, but the balancing avoided any humming pickup problems, so I'd have no qualms about sound quality for recording.

I also experimented with a resonator guitar, and found that the best sound was achieved by fixing the pickup directly to the metal resonator, because very little of the vibration comes off the wood in these instruments. While careful placement gave a sound that was fairly close to that of the instrument heard acoustically, the pickup captured every little contact noise — which unfortunately meant that when playing slide, any knocks were amplified to an unacceptable level. Used with a violin, however, the fact that the pickup loses some of the 'string edge' can be a distinct advantage, as it effectively adds something of a ribbon–mic character to the sound, making it a little smoother and more full–sounding.

Every contact pickup system is something of a compromise, because it can only pick up vibrations from one part of the instrument's surface, whereas when we listen acoustically we hear a blend of vibrations from all over the instrument, as well as some direct sound from the strings and, of course, reflections in the room. But once you've accepted this inherent limitation, if you take the time to find the correct placement, the Schertler DYN transducer performs remarkably well, delivering a full tone and low noise. In a live situation, the susceptibility to feedback will depend a lot on the resonant characteristics of the instrument to which it is fitted, but in the studio you could easily treat it as just another mic feed.

Where several acoustic instruments are being recorded together in the studio, this pickup is a great help in reducing spill without compromising tone, although, as I mentioned earlier, if a guitar also has an under–bridge piezo system fitted, it may be worth recording the output from this separately and then adding in just enough to bring back the edge when mixing.

With a street price of about £275 $450, these Schertler pickups aren't exactly cheap, but then they do a better job, and yield more mic-like results, than any other contact pickup product that I can recall trying. What's more, there are more in the range, and they work on all kinds of stringed instruments from mandolin and guitar to cello, violin and double bass — and you can even use them on pianos! In short, if your studio handles much in the way of acoustic instrument work, Schertler's DYN system could prove to be a very useful problem–solver. Paul White

SUMMARY The high-end Schertler DYN–G acoustic pickup delivers professional quality results. A surface–mounted device, it's designed mainly for live use, but it also offers distinct advantages in the studio when separation is an issue.

Systems Workshop +44 (0)1691 658550.

Schertler USA +1 425 822 0102

Boss DD7 Digital Delay Pedal

Boss's DD7 includes an expression/tap–pedal input, which overcomes some of the more frustrating limitations in their previous single–pedal delay effects.Boss's DD7 includes an expression/tap–pedal input, which overcomes some of the more frustrating limitations in their previous single–pedal delay effects.Boss have always been one of the front runners in the development of stomp-box format digital delays for guitar — in fact, the DD2 (their first such pedal) was launched way back in 1984, a full year before SOS was unleashed on the world! I've owned a couple of these pedals — the DD3 and DD6 — and I still love them: in fact, my pedalboard is rarely without at least one of them. So when I heard that Boss had released the new DD7, I was keen to take it for a test–drive.

The physical form of the DD7 offers few surprises, and it's easy to take it for a DD6 on first glance — the same familiar single-pedal format; the same colour scheme; the same red 'Check' LED; a pair of jacks on each side for the input and output signals and so on. As with other such pedals, it can run off a PP3 battery, or a standard 9V supply (so no need, as with so many pedals these days, to faff around with wal-wart PSUs or purchase expensive multi-voltage power supplies).

As I said, there are no surprises there, but there is one obvious difference — a third input jack, to which you can connect an expression pedal or a footswitch. This opens up a whole new world of possibilities: not only can you use an expression pedal to give you real-time control over delay time, feedback and effect level (a great way to get more inventive with your sounds) but you're also able to use an external footswitch to control tap–tempo. My biggest gripe with the DD6 was having to stomp–and–hold to access tap-tempo mode, and then stomp–and–hold again to be able to switch the effect on or off. I've never been a huge fan of the twin–pedal format, and it's great not to have to lug a bigger pedal around just so that you can control something as simple as this.

But the new pedal differs from its predecessor in less visible ways too. For the most part, it's a case of more is better: there's a longer delay time (nearly six and a half seconds in Long Delay mode, whereas the DD6 had just over five), and Hold mode offers a much more generous looping time, allowing sound–on–sound recording of up to 40 seconds.

But it isn't just that the numbers have grown for the exisiting effects: there are also some new delay modes. Modulation Delay won't set your heart beating, but its lush–chorus sound is a useful addition. Analog Delay mode is more interesting, because it models the sound from Boss's own DM2 analogue delay pedaal — but gives you much longer delay times than the original pedal. I really like the DD series for the digital delay, but it's great to have the softer analogue sound available at the turn of a dial.

Another feature — and one that's useful in the studio — is that you can send separate signals out of each of the output jacks, which means that you're able to take the dry signal out of one and the wet out of the other. It would be easy enough to patch a DI box in at the right place in the effects chain and tap off the dry signal before it hits the pedal, but if nothing else, it's at least one more dodgy patch cable you won't have to worry about.

I didn't get around to testing the battery life, but delay and loop pedals such as this are always very thirsty: Boss state that a carbon battery will give you 1.5 hours continuous use, and an alkaline battery up to six hours, so although a battery is included in the price, I'd suggest using a mains–powered PSU — unless you plan on marrying someone whose father runs a battery factory. Boss recommend using their own PSU, of course, but I had no problems using other commonly available ones.

So is it worth it? At a street price of about £100 $160, the DD7 is pretty much the same price as the DD6, but it gets around some of the minor gripes I had with the DD6 and offers much more. I wouldn't say it's my favourite delay pedal out there — there are larger and pricier pedals that offer many more sounds and functions (such as Eventide's Time Factor that I reviewed back in SOS March 2008), but it is certainly one of the most convenient, and probably the best I've used in single-pedal format, or that you can power from a conventional 9V supply. If you're in the market for a new delay pedal, I'd definitely recommend trying the DD7 — and using it with an expression pedal if possible (it would be worth taking one along to the demo room at your local store). I'll be very surprised if this doesn't fly off the shelves every bit as fast as its predecessors. Matt Houghton

SUMMARY This stereo delay pedal is a very useful update by Boss to what's now a very familiar concept. In short, if you liked the DD6, the DD7 will be right up your street.

Roland UK +44 (0)1792 702701.

Roland US +1 323 890 3700.

Emerson Williams Bluestone Pro

In SOS October 2008, we ran a review of the Emerson Williams Bluestone Pro dummy load and speaker–emulator, in which we stated that the "combi socket provides a balanced mic-level feed". This socket actually provides a line–level signal, so apologies to anyone out there who's been hearing fizzy distortion from their Bluestone Pro!