We frequently receive requests for recommendations about what Macintosh configuration to buy for running Canary. "Which Mac should I buy? How much memory will I need? What size hard disk should I get?" We cannot provide specific answers to questions like these because there are too many variables that are unique to each user's situation, and there are many options from which to choose. Also, prices and availability of system components vary so quickly that any recommendations we make would rapidly become obsolete.
Although we can't recommend a particular Macintosh configuration, we can offer some suggestions for how to go about making these decisions for yourself. This document provides information that may be helpful as you decide how to allocate limited resources among the components of a complete sytem.

A strategy for decisionUnless you are in the rare and enviable position of having unlimited money to spend, you're going to have to consider a lot of trade-offs such as speed vs. memory vs. storage space. The process is less bewildering if you can decide on what your minimum requirements are for each piece in some particular order rather than all at once. We recommend considering each of the following questions below in order, particularly if you're new to these kinds of decisions. Each question is discussed in some detail later:

1. How much money can you spend? We can't help you with this one.

2. How much memory (RAM) will you need? The amount of RAM in your machine puts a limit on the amount of data Canary can work with at one time: how many signals you can have open at one time and how long they are. Consider this first (before deciding on a particular Macintosh model), because if you don't have enough memory to work with your particular signals, you can't do your work. Period.

3. How much storage space will you need and in what form (hard disk, removable cartridges, archival backup media)? Most users want to be able to save sound data for some intermediate time period or for long-term archiving. The answer to this question will depend on how much data you need to have accessible at a given time.

4. What printer will you get? Do you need to print high-quality spectrograms (for presentations or publications)?

5. What other features (unrelated to Canary) do you need (e.g., CD-ROM drive, big monitor)? We can't help you with this one either.

6. Which Mac can you afford to buy after satisfying all the previous requirements? This decision comes last because the main difference between processors is speed. For most users, speed is nice but not critical.

How much memory (RAM)?

The amount of memory (RAM = random access memory; not to be confused with "storage," which usually means hard disk space) available to Canary determines how much data (i.e., how many seconds of sound) you can work with at one time.

Canary requires a minimum of 2.5 megabytes of RAM to run. This figure refers to memory available for Canary itself, not the total amount installed on your machine. Keep in mind that system software can take up anywhere from about a megabyte to several megabytes, depending on what control panels and extensions are installed.

Although you may be able to run Canary on a Mac with as little as 8 Mb of RAM, we recommend at least 12 Mb for most applications. Depending on how you use Canary and how your system is configured, you may need substantially more.
You can use the following information to estimate how much memory you're likely to need. Canary's minimum allocation of 2.5 Mb is sufficient to make a medium-resolution spectrogram (resolution = 5.8 mS x 43.5 Hz) of one signal slightly more than 2 seconds long, digitized at 22.3 kHz. The actual amount of memory needed for any particular application is roughly linearly dependent on the number and length of signals that are to be open at one time, the sampling rate at which the signals are digitized, and the time and frequency resolution of spectrograms that are calculated. Even for a given signal, there are hundreds of combinations of spectrogram parameters that will require different amounts of memory. However, the following formulas can serve as a guide to the approximate amount of memory needed for signals of different lengths digitized at 22.3 kHz (remember that 1000 Kbytes = 1 Mbyte):

• Waveform only: approx. 1700 Kbytes + (100 Kbytes/sec * signal duration)
  

• Waveform + medium-resolution spectrogram (e.g., resolution = 5.8 mS x 43.5 Hz): approx. 1700 Kbytes + (300 Kbytes/sec * signal duration)
  

• Waveform + high-resolution spectrogram (e.g., resolution = 1.4 mS x 10.8 Hz): approx. 1700 Kbytes + (2900 Kbytes/sec * signal duration)
  

If your signals are digitized at 44.1 kHz, these requirements should be doubled.

After you decide how much memory you want to have available to Canary, add 2 to 7 Mb for the Mac's operating system. (The amount of memory that the System requires depends on how many extensions and control panels you have installed.) If you want to run other programs at the same time as Canary, add in memory requirements for them too. The result is the minimum amount of memory you should have installed in the Mac.

Depending on which model of Mac you buy, you may be able to add more memory to it later if you find that you don't have enough. Mac models vary with respect to their memory expandability; see the discussion under "Which Mac model?" below.

To save money on memory, you might consider buying a software product called RAM Doubler(tm), from Connectix, Inc. RAM Doubler uses some clever memory management techniques to allow you to run more programs at once than you actually have memory installed for. The program may cost less than buying more memory, and has been very favorably reviewed. Although we cannot make any guarantees or endorsements of RAM Doubler's performance, we know of several Canary users who are quite happy with it, and have heard no complaints about it. Even if you use RAM Doubler, however, you machine should have at least enough RAM installed for Canary and the operatings system.

How much data storage?

Digitized sound can gobble up space on your hard disk fast. To figure out how much storage you're going to need, multiply the sample size in bytes (8-bit samples = 1 byte per sample) times the sampling rate (samples per sec) by the average length (in seconds) of the signals you'll work with. This will give you the average storage requirement for each file (this is assuming you're just saving sounds, not spectrograms). How many files do you want to keep around?

Hard disk
Because sound files take up so much space, you'll probably want to limit how many you keep on your hard disk at once. But remember that you can never have too much hard drive space.

Other storage options
For a convenient and flexible way of storing lots of sounds without using up your entire hard disk, consider a removable-cartridge drive, such as a Zip drive or a SyQuest drive. Alternatively, you might want to burn your sound files to a CD, which is also a fairly safe way to archive sound and data files.
Remember that every hard drive ever made is guaranteed to fail. The only question is when.

What kind of printer?

If you want to be able to print publication-quality spectrograms, you will need a laserprinter with at least 600 dot-per-inch (dpi) resolution.

Which Mac model?

Canary 1.2.4 will run on any PowerMacintosh or any 68020 or better Macintosh that is equipped with a math coprocessor and adequate memory (RAM; see below). A separate version with identical features, Canary 1.2 LC, is available to run on 680x0 machines that lack a math co-processor (such as the various LC and PowerBook models that are equipped with the 68LC040 processor). Performance without a co-processor is drastically slower than with one; if you are buying a Mac specifically to run Canary, you should probably avoid machines without a co-processor. If you already have such a machine and want to run Canary on it, you can use the LC version of Canary as long as you're not in a big hurry to see your results!

Processor speed

The main difference among Macintosh models as far as Canary is concerned is speed of calculation for spectrograms, correlations, and some measurements.

Canary's performs best on PowerMac machines because of their faster floating-point operations. Next fastest are machines equipped with the 68040 processor (e.g., Quadras). Machines that lack math co-processors are generally the poorest performers. Within each of these machine classes, there are models that operate at different speeds. For detailed comparisons of machine speeds, see back issues of magazines such as MacUser or MacWorld. For information on which processor is in each Mac model, consult your Mac dealer.

The table below shows the time required for Canary to make a spectrogram of a 2-second signal digitized at 22.3 kHz on various Macintosh models.

Memory expandability

Besides speed, another issue to consider is future memory expansion options. Memory (RAM) comes in plug-in memory modules called SIMMs or DIMMs, which come in various sizes (e.g., 4, 8, or 16 Mb per SIMM or DIMM). Different Mac models have different numbers of SIMM/DIMM sockets.

There are two ways of increasing the memory in a machine: if there are some memory sockets still empty, you can add more memory modules; alternatively, you can replace some or all of the existing modules with higher-capacity modules (e.g., replace some 4 Mb SIMMs with 8 Mb SIMMs). Adding memory gets you more memory for your dollar because you don't have to discard some or all of the modules that are already installed. So if you think you may want to add memory later, you might want to look for a model that will still have some free memory sockets when you buy it.