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Assignement of the system ressources |
BPM Studio processes all frames of the mp3 file and therefore requires
more ressources than other single MP3 players such as WINAMP(TM).
Further BPM Studio offers a wider range of functions than these players
and a direct comparison to them makes no sense. For this reason it is
essential that each soundcard is assigned to a separate IRQ which is not
in use by any other card or PC component. Also the other components like
harddisk, CD-ROM drive and graphics card have a high influence on the
system's performance. For the professional use it is highly recommended
to run BPM Studio solely on the computer.
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Latency of the drivers |
Latency means the delay between a command such as play, pause or stop
and the moment when the soundcard reacts on it e.g. starts playing.
Generally these latencies depend on the used driver model or the driver
itself. The lower the driver latency is the better it is suitable for
exact beat mixing.
- Kernel driver: 4...13 ms, this driver is definitely the fastest.
- DirectSound drivers: 20...30 ms, 150...300 ms (!) with emulated
drivers
- MME Wave drivers: 70...180 ms, depending on the selected buffer
size in the program options
- ASIO/EASI drivers: 20...50 ms, the latency is generally set up in
the ASIO driver options.
As you can see from the list above the
kernel driver and the direct sound drivers are to be preferred because
both drivers work in the kernel mode of the operating system and are
therefore relatively independent from the system resources. The ASIO and
WAVE drivers are running quite stable too and are very suitable for
background music as in dance schools, pubs a.s.o. BPM Studio supports
WAVE drivers because they are available for almost any soundcard and
work properly even with NT.
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| DirectSound
Driver |
This is the fastest and most stable standard driver. Depending on the
hardware configuration toggling between cue and play takes less than
20...30 ms. The sophisticated DJ putting a big weight on exact beat
mixing and using the cue and play functions of BPM Studio will prefer
this driver model. If the kernel driver is supported by your soundcard
it is recommended because of its even lower latency and stable playback.
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| Kernel
Driver |
This driver developed by ALCATech adresses the soundcard from a very low
level in the kernel mode and provides an extremely high priority with a
very short latency of 4...13 ms and highest stability. The kernel driver
utilizes the functionality of existing drivers such as Direct sound and
therefore works on most soundcards, even on those which could only be
run with ASIO or WAVE drivers because of the missing DirectSound drivers
and tended to produce dropouts.
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ASIO-Driver |
This driver developed by
Steinberg is
designed as an interface for multichannel soundcards. It is a little
slower than the direct sound drivers and tends to produce drop-outs as a
user mode driver at high resource consumption. This driver is suitable
for background music purposes and works quite well. The latency is
between 6 and 50 ms and can be adjusted usually on the driver options.
For BPM Studio latencies from 20 to 46 ms are recommended otherwise
drop-outs can occur. The correct has to be detected by „trial-and-error“.
On some of the tested cards ASIO drivers are running unstable.
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| EASI
Driver |
This driver developed by
eMagic is equivalent in function and stability to the ASIO drivers
and is eMagic's answer to Steinbergs ASIO. All statements made on ASIO
are valid on EASI too because they differ slightly only. EASI is rarely
supported and threrefore almost without meaning.
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| WAVE-Driver
(Wave out) |
This is a very stable driver which can be use alternatively to the wave
driver but provides hight latency times. On multichannel soundcards
without DirectSound or ASIO drivers it is the only way to adress the
differnt channels separately. It is very suitable for background music,
but not for live DJ's. Latency is between 120...200 ms.
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