Rebis have now added a sound sampler to their range of rack modules. The RA226 offers keyboard control of pitch along with a generous sample length.

It's hard to believe that this tiny module contains all the necessary electronics as it's little over two inches wide, but it certainly seems to do the job. In its standard form, the RA226 will store up to eleven seconds of sound with an 8kHz bandwidth, though you can halve the time and double the bandwidth or vice versa if you need to. However, that's not all. The stored sound can be played from a CV keyboard and the trigger inputs accept either V or S trigger formats.

The memory part of the RA226 is modular which means that extra memory cards can be fitted to give a maximum storage time of 44 seconds with an 8kHz bandwidth or a staggering 88 seconds with a 4kHz bandwidth. When a sample is played back via a keyboard, the pitch is changed by either speeding up or slowing down the sample, so obviously the length of the sample will also change. However, when a sound is played back at a higher pitch, this system automatically adjusts the output filters so that an 8kHz sample transposed up by one octave will have a full 16kHz bandwidth. Conversely, when a sample is transposed down by one octave, the bandwidth halves accordingly.

Overview

This little module is designed to work as part of the Rebis rack system but you can power it up from a separate power supply at a pinch if for any reason you're determined not to buy the rest of the rack. Whilst it's an attractive sampler in its own right, the RA226 will also function as a digital delay and if you don't have a keyboard or a sequencer with a CV output, you can still trigger fixed pitched samples to create percussive sounds or even drop pieces of vocal line into a mix. The control range when the CV input is used is two octaves which is adequate for most musical purposes, and the long sampling time means that no looping facility is necessary. You can however trim the beginning and end of a sample using the simple front panel edit controls, and a composite sample may be built up from separate slices of sound by butt jointing several short samples together if you need this facility.

Normally, whenever I review a sampler, I have to level the criticism that there is no sound trigger but I can't say that about this model; there's one built in. This lets you use the sound source itself to start the recording procedure and makes sampling much less of a hit and miss affair.

Controls

Everything looks quite simple; there are six knobs, six buttons and six LEDs (if you don't count the level meter). There are two modes of operation, Sampler or Delay, so I'll look at the delay mode first as it is the simplest to describe.

To use the unit as a delay, the two edit controls Start and End should be set to fully anti-clockwise and fully clock-wise respectively. If the Pitch control is set to +1 (fully clockwise), the maximum delay time will be 1.4 seconds with a 16kHz bandwidth. The reason that the maximum delay time is far shorter than the maximum sampling time is that not all the memory is used; some is reserved for sampling only and anything stored in these areas is retained even when the unit is being used as a delay. The End control is used to set the exact length of the delay and Feedback works in the customary way to produce repeat echoes.

The Input Level control is used to set the input sensitivity and by monitoring the signal on the four section LED meter, the maximum input can be used to minimise noise; of course too much input will cause distortion. Another control that will be familiar to DDL users is the Mix control which is used to balance the input signal with the delayed signal. When used in conjunction with a mixing desk, this control would normally be set to give a delay only signal as the dry signal would be provided via the desk.

"...I would have liked to be able to play reversed samples from the keyboard and another octave of range would have come in quite handy too."

Sampling

A sample may be stored simply by pressing the Record button, at which point the LED next to the button will flash. When an input signal is present, the automatic trigger circuit will start the recording process and the LED will stay on until the recording is complete when it will play back once automatically so that its quality may be verified.

Once the sample has been successfully captured, it may be played back manually in either the forward or reverse mode by pressing either the Forward or Reverse buttons. (They're so logical up in Stourbridge!) So that you don't have to hold the buttons down for the whole length of the sample, there's a Latch button and when this is set, a momentary action will cause the sample to play all the way through. If you want to have the sample loop continuously, this may be achieved by pressing the Loop and Latch buttons simultaneously; if only the Loop button is engaged, the loop may be stepped through a section at a time.

Of course it is handy to be able to clean up the beginning and end of a sample and this is easily achieved using the edit controls, Start and End. These rotary controls vary the start and end points of a sample in a most logical way but if their positions are set to overlap, a 'window' may be removed from the sample, or in other words, a section in the middle of the sample may be removed and the two ends joined up again. Because joining any two sounds is likely to cause an audible glitch, it may be necessary to adjust the edit controls for the least obtrusive join. The same is true of composite samples in which several sections of sound may be joined end to end. The system allows you to perform this trick by using the edit controls to define which part of the memory a sample will be recorded into.

A sample recorded with the Pitch control set to zero will be transposable by one octave either up or down but a sample recorded with the Pitch control at +1 will only be transposable downwards (and upwards for a setting of -1). The record bandwidth is automatically modified according to the setting of the Pitch control, as is the sampling time. Musical playback may be achieved by connecting a one volt per octave keyboard with a suitable V or S trigger to the CV and gate inputs, but you may need to experiment to find out which two octaves on the keyboard operate the sampler as this may vary from synth to synth. In this mode, the Pitch control may be used to fine tune the sample to the keyboard.

In Use

On connecting up a trusty old ARP Axxe, I ran into problems right away as the Rebis was set to accept control voltages in the range two to four volts whilst the ARP gave out zero to three volts, so only the top few notes would work. On phoning Rebis, I was informed that they were aware of this problem and that production models would be equipped with a means of matching up the CV input to different types of synth. Also, it was suggested that by changing the control voltage range to operate from a half a volt up to two and a half volts, compatibility with the majority of monosynths would be ensured without the need for further adjustment. That's one advantage that Rebis have; as they are British and fairly small, they can instigate such modifications as are necessary without undue procrastination.

The test was continued using a Roland MC202 which could be set to give a CV output in the right range and from then on was fairly straightforward.

"...where the Rebis really scores is in its long storage capacity."

Sampling a sound is made easy by the automatic sound-activated trigger but you have to be careful not to make any unwanted noises before the sound you want to capture otherwise you might start the record process by accident. If you do capture a small amount of unwanted sound, this may be removed by adjusting the Start control until the sample starts exactly where you want it to. Depending on whether you use the Latch function or not, the sample will either play all the way through or stop as soon as a key is released. Of course the sample will restart when a new key is pressed regardless of the Latch switch status.

One problem becomes evident quite early on though, and that is that samples with no natural decay curve tend to sound truncated when the sample runs out or when the key is released. This is also true if a sample is shortened using the Edit controls and some sort of gentle fade-out rather than an abrupt cut-off would be more artistically acceptable. One way round this problem is to feed the output of the sampler back through the external audio input of the synth that you are using and set the Latch status to on. What this means is that the sampled sound will be fed through the filters and the envelope shapers of the synth so you can not only modify the envelope of the sound, but also apply some creative filtering. This results in a far more natural sound and this mode of operation is to be highly recommended.

Another advantage of this method of operation concerns noise. Any sampling system introduces some degree of quantisation noise, and whilst this may be masked by the sound of the sample itself, it's often audible at the tail end of samples or when the sampled sound contains little in the way of high frequencies to mask the noise. An example of this might be bass guitar, but by using the filters in the synth itself, the frequency response can be tailored to suit the sample and, as the filters can be arranged to close down as the envelope decays, the noise at the tail end of samples may be considerably reduced.

One limitation of the sampler is that the reverse play mode cannot be used from a keyboard, only from the manual front panel buttons and this is rather sad as some samples can sound quite splendid when played in reverse. The reason for this limitation is that there are simply not enough pins on the rack connector system to support this option but I'm sure that an extra front panel switch would get around the problem; it's just finding somewhere to put it. On calling Rebis on this matter they informed me that they would put a simple mod in the handbook which would enable users to get round this limitation.

I'm still not convinced about this business of building up sounds by butt jointing several short samples as the results always sound messy to me and it is difficult avoiding clicks where the samples join. Still, the majority of samplers seem to offer this facility so I can only assume that some people use it and in this respect, the Rebis is no worse than any others that I have tried and indeed it is better than most as the software joins the samples at zero crossing points.

Another popular and viable use is to sample percussion sounds which may then be used to replace sounds already on tape. The best way to do this is to use the sound trigger to replay the samples and to connect a frequency conscious noise gate between the tape track and the trigger input. In this way, false triggering should be eliminated.

"...it's a good all round piece of gear that will probably find itself well used for a variety of applications..."

Conclusions

This is a serious product offering a long sample duration and as such does not fall into the budget category. Having said that, the basic unit will cost £573.59 including VAT which isn't too bad if you already have a rack to plug it into. If you don't have a rack, the cheapest option is to also buy the 14 unit frame system which costs £113.62 including VAT and includes the power supply. This low price is maintained in the hope of tempting you to fill the remaining spaces with more Rebis modules at a later date.

Should you want to add more memory, the extra cards will cost you £216.32 each including VAT, and you can fit up to three to give the maximum 44 second at 8kHz storage capacity.

On the criticism side, I would have liked to be able to play reversed samples from the keyboard without having to do any mods and another octave of range would have come in quite handy too. The mod mentioned earlier will in effect provide another trigger input socket which will play back the samples in reverse. This should be easy for most owners to do and involves only a couple of components and some simple wiring.

Some sort of decay envelope shaper would also have helped, but as I pointed out earlier, you can use the external audio input of your synth to obtain the same effect. Also, some form of looping could have come in useful on occasions.

For the price of the Rebis system with its full compliment of memory, you could buy the Akai polyphonic MIDI-controlled sampler which is probably a better bet if you want to use the machine purely for music, but where the Rebis really scores is in its long storage capacity. This makes it a very useful alternative to 'spinning-in' short sections of music or vocal in a recording situation though being an eight bit system, it may be a little too noisy for exacting use.

It's probably fair to say then that whilst this unit will not be all things to all men, it's a good all round piece of gear that will probably find itself well used for a variety of applications in any recording environment.

Further details from: Rebis, (Contact Details).