Virtual Memory Windows 2000 does not allow disabling virtual memory. This is not a problem. I never recommend disabling VM, and Windows 2000 manages it much better than Win9X. You can choose the disk volume where the VM file will be placed. Usually you will want a single file. If you have several disks, do not put it in the same disk that you use for the audio files. The settings recommended by Windows 2000 are usually adequate, but some tweaking can prevent possible problems. When you are running Windows 2000, it will use the smallest swap file it needs. But if you do something that requires more RAM, Windows will enlarge the swap file to create memory headroom. If this happens when you're recording or playing back, you could experience real performance problems when Windows tries to enlarge the swap file. Therefore, set the minimum virtual memory size so that the swap file should never need to grow. 256 MB should be the smallest value you should set, but 384 to 512 MB are better. The maximum size...

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Frequency filters A frequency filter modifies the amplitude response into a determined bandwidth. What we know in the audio world as an equalizer is a frequency filter. I won't cover here a description of audio equalizers from a usage point of view, what surely you know well. If it is not so, you might want to read the series about equalizers from Lionel L. Dumond. What I'll explain here are some basic properties of digital filters. Filters change audio in two ways: by changing the amplitude vs. frequency, and by changing the pahse vs. frequency. The amplitude response is represented by a graph where the X axis is the frequency and the Y axis the amplitude gain. The phase response is represented by a graph where the X axis is the frequency and the Y axis is the phase. There are two main kinds of digital filters: IIR (Infinite Impulse Response), and FIR (Finite Impulse Response). IIR filters An IIR filter is the mathematical...

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Introduction Understanding basic DSP (Digital Signal Processing) theory is really helpful to get the most of digital audio recording and processing. This series of articles is directed toward musicians and sound engineers, so, the issues will be covered mostly in a practical way, and the necessary theory will be explained as good backgrounder or just to understand the practical consequences, not to be a deep or complete reference for DSP math. The series will begin with the more basic issues, assuming that the reader doesn't know DSP theory at all, allowing anybody to follow and understand the explanations. Very often, it's difficult to understand issue A without first understanding issue B, while B cannot be fully understood without first understanding issue A, so, don't worry if you can't understand completely something, accept it as a hypothesis, and you will understand better each time as you follow the series. If you have questions, you can use the DSP theory forum...

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Recording audio on a computer places demands on the computer never anticipated by the computer's creators or operating system manufacturers. For example, if you record on a large disk formatted with FAT32 in Windows 95, Windows will format the disk with small block sizes. This is an attempt to avoid wasting space, since the entire block is consumed even if it only contains a single byte. With "normal" sized files, small block sizes mean less wasted space. With audio, however, small block sizes mean excessive reads and poor disk throughput. In a future article I will discuss the proper techniques for setting the right block sizes. For the moment I want to discuss Virtual Memory. Windows' default Virtual Memory settings are usually not good for audio. First of all, Windows likes to maintain a flexible swapfile size. This is good for typical usage because it allows Windows to increase the size of the swapfile as you load more and more programs into memory. With audio recording, however, disasterous...

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