NOTE - This article applies to Solo version 1.
Most consumer quality sound cards are too slow to be used acceptably with Solo - it is not recommended that you attempt to use a SoundBlaster or similar, or any onboard soundcard as these tend to be far too slow to be deemed acceptable for use - the latency of the card is extremely important when talking 'live' to a caller!
WDM Driver
Any soundcard intended for use with Solo must have a 'Windows Driver Model' (WDM) driver installed (also sometimes referred to as DirectSound compatible). If this is not the case, then the soundcard will appear installed in Windows, but will NOT appear as an available input or output for Solo.
Performance
To obtain optimal performance within Solo, PCI soundcards should be able to operate as a 'Bus Master'. All PCI Express (PCIe) cards should be able to perform optimally although this of course depends on the soundcard.
Granularity
The granularity (measured in samples) can be adjusted to obtain the best performance without loading a card too heavily. If the granularity is set too low, clicks are often heard in the audio of the callers. Set too high, and the audio will be noticeably latent. 192 is the minimum granularity and represents a latency of 20ms. Increasing the granularity results in a proportional increase in the latency, so a granularity of 576 represents a latency of 60ms. It is important to remember that there may be other latency in the phone call such as the normal delay experienced on the telephone network, especially to mobiles.
Cards with good performance
- Digigram HR and PCIe series of VX and PCX soundcards, also UAX range and LX6464ES (192 granularity). VX222v2 (252 granularity).
- Echo digital 'miamidi' (192 granularity). Please make sure that the card is locked to 48k using the Echo digital control panel in the Start Menu or it will not work with Solo.
- Terratec Phase 22 (252 granularity?)
- Lynx AES 16
- Audioscience 504x (384 granularity) (WDM driver version at least 3.08.06)
- Edirol UA-25EX USB Audio Interface (252 granularity)
Cards not tested but expected to have good performance
- Audioscience 66xx, 65xx, 6416, 66xx (PCIe) (WDM driver version at least 3.08.06)
Cards which work but dont perform acceptably for onair use (note - these are suitable for use as a music on hold feed where the latency is not relevant)
- M-audio Delta 44 (reported to work at 600-800 granularity)
- Audioscience ASI4xxx (reported to work at around 800 granularity) (WDM driver version at least 3.08.06)
- Plantronics DA40 USB headset adapter (800 granularity).
- Most 'home user' soundcards - tend to need very high granularity (1000+). Specifically tried and not recommended are SigmaTel and Soundmax onboard soundcards.