Kwurqx
Happy synthing
- Lid sinds
- 16 mei 2017
- Berichten
- 918
Een heel oud stukje (2007) over voor- en nadelen van verschillende bus soorten.
Maar nog steeds waar.
PCI: Parallel en controller op host (op de computer). Mag rechtstreeks naar de omliggende hardware (o.a. CPU). Laagste latency.
Firewire: Serieel en eigen controller (op de interface). Lagere "topsnelheid" dan USB. Maar wel stabieler (vanuit de architectuur). Mag rechtstreeks naar de omliggende hardware (DMA). Lage latency.
USB: Serieel en controller op host (op de computer). Abstractie lagen. Half-duplex (USB 1.x en 2.x). Hoogste latency.
Inmiddels is USB denk ik het meest gebruikt (in de niet-pro sfeer) en is de overhead van USB grotendeels gecompenseerd door brute rekenkracht.
Maar het is niet de meest efficiƫnte oplossing.
Maar nog steeds waar.
PCI: Parallel en controller op host (op de computer). Mag rechtstreeks naar de omliggende hardware (o.a. CPU). Laagste latency.
Firewire: Serieel en eigen controller (op de interface). Lagere "topsnelheid" dan USB. Maar wel stabieler (vanuit de architectuur). Mag rechtstreeks naar de omliggende hardware (DMA). Lage latency.
USB: Serieel en controller op host (op de computer). Abstractie lagen. Half-duplex (USB 1.x en 2.x). Hoogste latency.
Inmiddels is USB denk ik het meest gebruikt (in de niet-pro sfeer) en is de overhead van USB grotendeels gecompenseerd door brute rekenkracht.
Maar het is niet de meest efficiƫnte oplossing.
http://homerecording.com/bbs/genera...usb-soundcard-softinstruments-latency-243308/
Advantages/disadvantages of PCI:
- Slightly lower latency.
- Not usable with laptops.
- Not usable with any current Macs.
- PCI slots being gradually phased out in favor of PCI Express (not compatible). Within a few years, motherboards with legacy PCI slots will be more expensive, specialized boards as ISA-capable boards became several years ago.
- Devices with converters on the card itself are often prone to noise in some computers.
Advantages/disadvantages of PCI Express
- Latency comparable to PCI.
- Tons more bandwidth for devices with ludicrous numbers of channels.
- Not being phased out.
- Generally significantly more expensive than PCI or FireWire due to economies of scale.
- Still not easily connected to a laptop.
Advantages/disadvantages of FireWire:
- Easily connected to almost any computer, including laptops.
- Robust against obsolescence by virtue of having bridges to most modern bus architectures.
- Slightly higher latency (minimum is on the order of 6 ms RTL) than PCI (minimum is on the order of 3 ms RTL). Note that an audible delay is about 30 ms RTL.
- Slightly higher CPU use than PCI (though not much).
- Converters are guaranteed to be outboard for better SNR.
- For maximum noise isolation, converters can be up to a kilometer away from the computer if desired (with appropriate optical FireWire transceivers and a long piece of fiber).
- Cheaper to implement than PCI Express, I believe.
- Only a handful of silicon vendors, so the drivers are usually pretty solid since they only have to maintain compatibility with a few different pieces of silicon.
- The potential exists for routing individual streams of audio directly from one FireWire device to another without the computer even being involved. (I've seen demos of this with certain pieces of hardware, though I forget the vendor.) This makes it really interesting for use as a glorified routing switcher.
Advantages/disadvantages of USB:
- Cheap.
- Significantly higher CPU load than FireWire or PCI.
- More prone to dropouts because all of the data copying is done without the benefit of true DMA (unlike FireWire or PCI) by the already-taxed CPU. It only has to get behind a little bit to totally hose things.
- Significantly higher CPU load than FireWire or PCI.
- Limited number of channels. It isn't a very good idea to go above two, and eight is right at the limit of usable.
- Significantly higher CPU load than FireWire or PCI.
- Slightly higher latency than FireWire even if all other things like buffer size are equal.
- Significantly higher CPU load than FireWire or PCI.
- Buffer size might need to be higher on slower CPUs due to lack of DMA.
- Significantly higher CPU load than FireWire or PCI.
- Lots of cases where the isoch pipe can go away.
- Significantly higher CPU load than FireWire or PCI.
- Lots and lots of buggy USB devices that don't properly conform to the USB Audio Class spec and thus often don't quite work consistently.
- Did I mention that it has significantly higher CPU load than FireWire or PCI?
- Limited power availability means no possibility of a bus-powered interface with usable phantom power.
- Oh, yes, and significantly higher CPU load than FireWire or PCI.
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