MaxMSP Operation and Compatability

Where is the processing done?

Directly on the computer's CPU. The processing occurs at interrupt level in the background so you can use your computer for other things at the same time, although if you do too much processing, the background begins to intrude rather severely on the foreground. There has been a tremendous increase in the speed of processor chips in the past year or two, and this is responsible for the ability for programs such as MaxMSP to perform so well in real time.

Why can't I download a patch onto my DSP card?

MSP's signal processing architecture is specific to general purpose computers.

Does MaxMSP take advantage of multiprocessors?

MaxMSP doesn't break audio tasks up and distribute them across multiple processors -- if you only consider the audio part of MaxMSP, there is no additional benefit to using multiple processors. Since OS X and Windows XP are "threaded" OSs, some applications (e.g., Logic Audio) make use of multiple processors by running some application code (e.g., MIDI and UI tasks) as one thread on one processor, and audio on another processor. While MaxMSP doesn't explicitly control how OS X distributes these threads across processors, there are some things you can do to realize some benefit from multiple processor systems.

There are three parts of MaxMSP that can potentially run in their own threads. Audio code and UI tasks run in their own threads, so it is possible that OS X or XP can move the audio to the second processor while the UI remains on the first. The MaxMSP scheduler can be set so that it either runs in its own thread, or run in either the audio or UI task threads using the DSP Status window (found in the Options menu):

• If "Max Scheduler in Overdrive" is off, the scheduler will run in the same thread as UI tasks.
• If "Max Scheduler in Overdrive" is on AND "Scheduler in Audio Interrupt" is on, the scheduler will run in the same thread as the audio code.
• If "Max Scheduler in Overdrive" is on and "Scheduler in Audio Interrupt" is off, the scheduler will run in its own thread.

You can use these settings to optimize the use of multiple processors, depending on what kind of UI and scheduling tasks your patch requires.

If you're running Jitter, it's important to know that Jitter processing typically takes place in the UI thread, and it seems that some QuickTime codecs support the explicit use of multiple processors to decompress frames.

What kind of performance can you get?

Because MaxMSP is a real-time program, the speed of your processor imposes a hard limit on what you can do. If you are serious about doing audio signal processing on your computer, you want the fastest machine you can buy. With a real-time program, running out of processing capacity means that the sound begins to distort, or your computer is extremely unresponsive, or both. We have seen dramatic improvements in processor speed recently, but once you start using MaxMSP, you may want even more.

We allow you to download Max/MSP and try it on your own computer because we don't want to misrepresent its performance. Its value to you is inherently tied to what it can do on the computer you own. If you try it and subsequently want to upgrade your computer or get a new one, well it's refreshing, since most people think that Photoshop is the only reason to buy a fast computer. You'll know otherwise.

Can I use a DSP algorithm I develop with MaxMSP in another audio program such as Cubase or Digital Performer or Pro Tools?

Yes. MSP contains a set of objects you need for building pluggo audio plug-ins for VST, MAS, or RTAS applications. You don't need to purchase pluggo in order to create your own audio plug-ins, and the pluggo runtime installer allows you to share your audio plug-ins with everyone -- even people who don't own pluggo . You can download a set of Tutorials and tools for plug-in developers here

Can I pipe a software synth into MaxMSP?

MaxMSP can receive data from ReWire instruments, and VST hosts.

Does MaxMSP support plug-ins for other audio programs?

Yes. MaxMSP contains an object called vst~ which lets you load a VstPlugin. Plug-ins in MaxMSP can be more interesting than the way sequencers use these plug-ins. For instance, you could load ten plug-ins and assuming you had the CPU power to do it, run them all in parallel. Or, using Max, you could generate algorithmic automation control over several plug-in parameters at once. You can also use VST instrument plug-ins and send them MIDI events, as well as ReWire devices.

What are the advantages of using an audio interface card with MaxMSP?

There are several advantages. The first is audio quality. Most I/O cards available on the market are 24-bit, while the OS 9 Sound Manager and OS X Core Audio is 16-bit. Since MaxMSP's internal processing uses 32-bit floating point numbers, there is definitely a loss in output resolution at the DAC. Most cards use digital inputs and outputs, eliminating CPU interference that reduces the signal-to-noise ratio obtainable from analog outputs that are touching the computer hardware.

Another advantage is latency. The design of the Sound Manager and the Macintosh audio hardware makes it difficult to achieve suitable latency performance. Using an audio card that MaxMSP supports directly allows you to bypass the Sound Manager completely.

MaxMSP 4.1 for OS 9 supports ASIO-compatible audio cards and interfaces; virtually all products advertised as Mac-compatible will work with ASIO.

MaxMSP 4.2 for OS X supports Core Audio. You'll need a Core Audio driver for your hardware to use it with OS X.

All version of Windows MaxMSP support ASIO, directX and MME drivers, as well as ReWire

Does MaxMSP work with Digidesign's Pro Tools hardware?

Yes, it does. If you want to use ProTools hardware such as an Mbox or Digi 001 with OS 9, you'll need to put the Digidesign DirectIO ASIO driver in your ASIO drivers folder. If you're using OS X, you'll need the Digidesign CoreAudio driver.

On Windows, MaxMSP uses the Digidesign ASIO driver.

What type of sound files does MaxMSP support? Can I record what I do in MaxMSP to a file?

MaxMSP reads and writes AIFF, Sound Designer II, WAVE, NeXT</noautolink/SUN(.au), and raw data files, and lets you import any audio file format supported by QuickTime. You can connect one or more audio signals to a hard-disk recording object in MaxMSP and record whatever you are synthesizing or processing. The file can contain up to 16 channels, and may be saved in a variety of sample formats from 8 to 64 bits. Additionally the buffer~ object can import the audio track from anything that is supported by QuickTime (e.g. .mp3, .mov, .avi, etc.)

I see that MaxMSP has delay line objects. How long can I make a delay?

Delay lines are stored in the memory of the computer, so the maximum delay time is limited by the amount of memory you have available. A mono delay uses 1MB of memory for each 5.94 seconds of audio. So, if you used 32MB for a delay line, you would have a delay line of more than three minutes (190 seconds). You can have many taps off the same delay line without using additional memory.
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