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Blank Software Alchemy

Sample Editing Software

Article from Music Technology, May 1988

A sample editing package to beat all sample editing packages? Robert Rich test-drives a universal editor that may be the answer to many a sampling studio's prayers.

Though originally intended as an editor for Ensoniq's new EPS, Blank Software's latest creation for the Macintosh has evolved into a universal sample editing program with some very unique functions.

Stereo sample above ('Pluck'), overview window below ('Gone').

IN THE FAST-MOVING world of high technology, clouds of hype and excitement can obscure good and bad developments alike. But after the hype boils away, we're occasionally blessed with that rare gem: a useful tool. At the last NAMM show, everyone was babbling about a new sample editing program called Alchemy; the word was "resynthesis."

Admittedly, resynthesis is an exciting idea. It can give precise control over the editing of a sample. First, the sample is broken down into a representation of its constituent frequency bands. The resynthesist can edit this information, then convert it back into a waveform. Until recently, high resolution resynthesis has been the reserve of expensive digital workstations and computer research facilities. The prospect of having such power to hand with a Macintosh and a sampler is an exciting one indeed.

I must confess that I had high expectations of Alchemy. To approach the program fairly, I had to revise my expectations a bit. Alchemy will not replace a big mainframe computer, but it is one hell of a nice sample editing package.

Although it's hard to ignore the untapped potential of some of Alchemy's more advanced features, this program can perform other tricks that alone might justify some of the hype surrounding it. In fact, the people at Blank Software themselves play down the resynthesis side of the program as some sort of afterthought. Some of Alchemy's other features include: communication with many kinds of samplers (what Blank call a DAN, or Distributed Audio Network); stereo sample editing; resampling; computer assisted looping with variable crossfades; digital EQ, and the usual complement of visual waveform editing functions. Here's the scoop...


ALCHEMY COMES ON two double-sided floppy disks, one containing the program, the other containing some samples to practice with. The program disk is well copy-protected, and it comes with a hard-disk installer that allows only one installation. Blank promise inexpensive updates and a backup disk to people who send in the guarantee form.

The manual is fairly complete and very well written. The introduction describes the basics of sound and digital audio, which may prove useful for those confused by some of Alchemy's features. It also provides a number of tutorials which demonstrate a lot of what Alchemy can do. The only things the manual lacks are an index (shame, shame) and more advanced technical information.

I tested Alchemy with an Akai S900 and a Mirage. Although everything worked well with a generic (Austin) Mac MIDI interface, I ran into some strange problems when I tried to use Southworth's JamBox 4+. Only one channel of a stereo sample would make it through to the S900, and I couldn't load anything from the sampler. MIDI transmission would mysteriously shut off after a sample dump. Most of the big problems went away when I put the JamBox into non-MIDI mode, but that meant constantly changing modes to hear the sample. But these problems are unlikely to be Blank Software's fault - the JamBox has a bit of a reputation for such complications.

The designers of Alchemy clearly intend the program to form the central hub in a network of samplers. Alchemy supports a number of different samplers all at once, unlike most of the other editing packages, which work with only one. Presently (version 1.0), Alchemy supports the Akai S900, E-mu Emax and SP1200, Ensoniq Mirage and EPS (with which I'm told it will perform real-time editing), IMS Dyaxis and generic MIDI sample dumps. Although Alchemy will prove useful to anyone with only one of these samplers, it should be a godsend for those with a collection of them.

Before you can really get down to using the program, you should tell it what samplers you have hooked up. A click on New Instrument under the Network menu opens a window that provides the necessary options. Scroll through the list of supported samplers until yours appears. For each sampler in your setup you can also assign a MIDI channel, MIDI patchbay controls, clock rate and Mac serial port outputs. Alchemy can communicate directly over SCSI or RS422, as well as over MIDI, so if your sampler can take one of these faster protocols you can really save time when dumping data. The Network menu shows all the samplers that you have set up, and Alchemy communicates with whatever sampler is selected under this menu.

Alchemy can read and save files in a number of different formats. Its preferred file format is Audio IFF, which holds 16-bit stereo or mono samples along with Alchemy's View Memories (see below). Alchemy also automatically recognises Sound Designer (16-bit mono) and Sound Lab (8-bit mono) files. You can save to these formats as well. This is great news for people with large collections of samples for incompatible samplers - at last there's a way to move these things around without leaving the digital domain.

One of Alchemy's best features is its ability to handle stereo files as a single entity. If a file is already in stereo, Alchemy will deal with it as such. A quick trip to the Soundfile Setup screen will allow you to convert any mono sample into stereo, although until edited both channels will contain the same information. The program displays stereo samples in two strips, with the left channel at the top of the screen and the right at the bottom. You can edit the two halves independently or, if you click or drag the mouse on the line between the two channels, you can edit them simultaneously.

Alchemy seems perfectly suited to instruments like the EPS and the S900, which play samples in stereo but only record in mono. By separately sampling both halves of a stereo sample, you can combine them within Alchemy and send them back to the machine for true stereo playback. The program will take care of quite a bit of the sampler's internal setup when it sends the two channels back out. Alchemy sends each channel separately, assigning them both to the same key range (which you select when sending a sample), and places them in the appropriate memory configuration for the chosen sampler.

While on the subject of files, memory and such, I should mention that Alchemy requires lots of memory - especially when performing fancier manipulations like resynthesis. The manual highly recommends 2Mbytes of memory and a hard disk. I used a 1 Meg Mac SE, and met up with quite a few "Insufficient Memory" prompts. Memory greed is fairly common when dealing with samplers, but be forewarned that you may need to fork out some more money for a Mac upgrade if you intend to use this program seriously.

"Editing: Many, though not all of its editing functions appear in other sample editing packages, but Alchemy's layout is particularly intuitive."


ALCHEMY CONTAINS QUITE a formidable list of functions, most of which appear as icons, readily available and in clear view. Many of these editing functions appear in other sample editing packages, but Alchemy's layout strikes me as particularly intuitive. I like having the tools where I can see them.

All the basic Macintosh Edit menu stuff is here, with some necessary additions. Clicking the mouse over a point in a waveform selects that point for insertion. Clicking and dragging the cursor selects a region of a sample. Along with the standard Cut, Copy, and Paste, Alchemy provides Mix, Insert, Extract and Clear options. Cut removes the selection, places it on the Clipboard and slides the remaining portions of the waveform together, while the Clear command removes selected regions of a waveform without saving them to the Clipboard, thereby preserving the last Copy or Cut. Unlike Cut, Clear does not close the gaps left in the original waveform.

The Paste command replaces the selected portion of a waveform with the contents of the Clipboard. If the selected portion is larger than the Clipboard, Alchemy shrinks the selection to fit the Clipboard. If the selection is smaller, the Clipboard portion will be truncated to fit it. (You can choose to have this to happen from the beginning or end of the selection.) The Mix selection works much like Paste, but mixes the scrapbook selection with whatever waveform is selected. The Insert command inserts the Clipboard contents at a selected point, increasing the size of the sample as it does so. If you paste, mix or insert a waveform into both halves of a stereo sample, a window pops up asking for the percentages of left-right panning... Very straightforward.

The program's most used commands appear as icons in the on-screen tool palette. The tools fall into seven categories: Mode, Display, Process, Waveform View and Cursor Location, View Memories and a numeric display.

The various view and display icons combine to form a very flexible graphic editing environment. Not only can you view and edit multiple samples on the screen at once (provided you have enough memory), but a click on the appropriate menu command automatically arranges the various windows into strips, layers or tiles. Screen icons assist navigation within a waveform window. Overview splits the window into two strips, the upper strip showing the entire sample, the lower one showing the current view of it. Snapshot puts your current waveform view into the upper of these two strips. You can zoom in or out of the current view with two magnification icons. Cursor Locators automatically centre the waveform view to selected portions, and the numeric display tells you exactly where the cursor is.

No matter how flexible the display, you can waste a lot of time searching for just the right region to edit - so there are eight view memories in Alchemy. Once you find what you need, you can save your selection or insertion point, with the waveform view and magnification depth, to any of these, which will then be stored with that sample (but only the sample is saved in the Audio IFF format).

Certain of the six Display icons do more than just change what you see on-screen. Clicking on the Speaker icon plays the selected wave on the Mac's sound chip, as does pressing the space bar. To hear loop points, keep pressing the mouse or hold down the space bar. The sound plays until you stop. Two Display icons set up parameters for processing the sample. The Loop Cursors icon switches on the loop function and places the loop boundaries at the end of the sample. You can then move the loop points around with the cursor, which changes into arrows when over the loop boundaries. Finally, the Threshold Bars icon sets up amplitude limit markers, which determine the levels for the Scale function (I'll come to that soon).

The Mode icons show which mode Alchemy is in: Selection, Waveform Draw or Loop Splice. Selection mode provides cut-and-paste editing, processing and other basic waveform manipulations. The program defaults to this mode upon starting up. Waveform Draw mode provides a pencil tool for hand-drawing waveforms. Clicking on the Loop Splice icon will open a window showing two sections of waveforms, the end loop point on the left and the start point on the right, with scroll bars underneath. This display shows the waveform where it jumps from the end to the beginning of the loop - a good indication of how good the loop will sound. Clicking in the scroll bars will now tell Alchemy to search for zero crossings - keep clicking until you find something that sounds good. It would be great if Loop Splice mode could find more than just zero crossings, as they're not always the best loop points, but what this mode does provide is quite useful.

If you can't find a good loop, Alchemy also gives you a Crossfade function. Once the loop has been tweaked, you simply choose the XFade Loop from the Process menu. Alchemy greets you with a window allowing you to adjust the percentage of the loop you want crossfaded. The slope of the crossfade can be adjusted from another menu selection called Fade Options, which sets the fade rates for all Alchemy's Fade commands (see below).

The nine Process icons actually mess with the sample data. Herein lies much of Alchemy's muscle. Three Fade icons do just what their names suggest. Fade Out takes the selected portion of a waveform and fades it to zero, with the fade rate selected in Fade Options. Fade In does the opposite. Crossfade takes whatever is in the Clipboard and fades it in with the selected sample (this is different from the Crossfade Loop). There are other Processing functions - Invert flips the waveform upside down (180 degree phase shift); Scale scales the amplitude of the sample to that marked by the Threshold Bars; Reverse plays the sample backwards and Replicate echoes the sample (a great way to use up memory). Then there are Analyze and Resynthesise icons. I'll deal with them presently.

Resampling plays a sample at one rate and records it at a different one. You need this in order to play the same sample at the same pitch on different samplers which tend to have different sample rates - thereby shifting the playback frequency of the original sound. Another benefit of resampling is storage of samples on the Mac at their highest possible resolution. You can then configure them to the requirements of different samplers. Alchemy seems to be able to resample a waveform with very little signal degradation - I couldn't hear any change, even after multiple resamples, except when I resampled at a much lower bandwidth. Alchemy apparently uses a non-linear 16-bit conversion format, which results in very clean processing.

"Resynthesis: By crossfading multiple segments of 'derived' waveforms you can create sounds similar to those of wavetable synths."

Also deserving of a mention is Alchemy's digital EQ - not very flashy, but very useful. You can select low pass, high pass and notch filters with controls over centre frequency, boost or cut amount (dB) and width of the notch filter. If these EQ controls aren't sufficient, you can always look to resynthesis...

Analysis/resynthesis editing window.


THIS IS THE one feature of Alchemy that doesn't quite live up to my expectations. To be fair, the creators of the program didn't really intend the resynthesis function to be much more than a very specific digital filter - for now, anyway. But despite its limitations, it can come in handy.

Once a waveform has been analysed, Alchemy displays a two-dimensional graph showing the amplitude for each of 16,000 or more frequency bands. This high resolution means that you won't hear any signal degradation upon resynthesising the sample, but it also makes the display a pain to edit. Adding to the editing difficulties is the fact that, though you can select multiple frequency bands for editing, you can't select more than one window's range at once. This fact alone makes applications like comb filtering hard work. I'd love to be able to convert mono samples into stereo by splitting overtones into left and right channels. Perhaps another day...

When Alchemy analyses a sample, it averages the envelope information out over the range of frequency channels. (This is a characteristic of the algorithm used, which is an FFT - or Fast Fourier Transform. To distinguish and edit separate envelopes for each frequency band requires a Phase Vocoder algorithm, a much more complicated affair.) This averaging has severe implications if you try to boost a single frequency band. The result is a very audible sine wave which dominates the resulting resynthesised waveform, basically ignoring the previous envelope for that frequency channel. This sort of problem is a built-in characteristic of the chosen algorithm.

But Alchemy's resynthesis does have its uses. If a sample suffers from aliasing noise, you can remove the offending tone. You can also tweak loops in which one or two overtones change pitch while everything else remains stable. The deviant overtones should appear as a cluster of adjacent frequency channels. Just find and remove the offending frequencies - no easy task, but the tool is there if you need it.

Once you resynthesise an edited portion of a sample, you'll find that a discontinuity appears between the edited waveform and anything immediately adjacent to it. A crossfade between the two portions of sample should remove this glitch. By crossfading multiple segments of "derived" waveforms you can create synthetic sounds whose structure resembles those of wavetable synths. It's not easy, but it provides hours of entertainment.

There's a lot of potential in Alchemy's analysis/resynthesis feature, but I can't help but feel mildly frustrated by how tantalisingly close this comes to being truly useful. But, personally, I feel the rest of Alchemy is good enough to forgive it its shortcomings.


WITH ITS NETWORKING features, convenient and powerful editing, stereo capability and digital signal processing, Alchemy makes sample editing a delight. If you work with a number of samplers, Alchemy may be the miracle you've been waiting for. Considering the number of musicians and recording studios that rely heavily on samplers, Alchemy's ability to act as the centre of a network will probably be its biggest selling point.

Though Alchemy's resynthesis function won't challenge the mainframes yet, Blank plan future revisions. We can also expect more samplers to be added to the compatibility list. Even without these improvements, though, Alchemy is the most capable sample editing program I've seen for a small computer.

Price £299 including VAT

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Publisher: Music Technology - Music Maker Publications (UK), Future Publishing.

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Music Technology - May 1988

Donated & scanned by: Mike Gorman

Gear in this article:

Software: Sample Editor > Blank Software > Alchemy

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Mac Platform

Review by Robert Rich

Previous article in this issue:

> Hi-NRG Paradise

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> Axxess MIDI Mapper 2.0

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