LabVIEW
Sound Card Question
Sylvia V wrote:
> To use your Audiophile 2496 sound card with LabVIEW the first thing
> you are going to need is a driver from the manufacturer. Most
> manufacturers already have a driver that works with LabVIEW or at
> least a driver written in C that then you can call from LabVIEW using
> Call Library Function Nodes.
A specific driver from sound card manufacturers for LabVIEW? Can you
show me some cards which have that?
The two possibilities I see are the standard Sound VIs in LabVIEW to
interface the Multimedia Windows driver for that card.
Alternatingly ASIO could be interesting but I haven't seen an ASIO
interface library for LabVIEW yet, although I was thinking about writing
one some time ago.
Rolf Kalbermatter
> To use your Audiophile 2496 sound card with LabVIEW the first thing
> you are going to need is a driver from the manufacturer. Most
> manufacturers already have a driver that works with LabVIEW or at
> least a driver written in C that then you can call from LabVIEW using
> Call Library Function Nodes.
A specific driver from sound card manufacturers for LabVIEW? Can you
show me some cards which have that?
The two possibilities I see are the standard Sound VIs in LabVIEW to
interface the Multimedia Windows driver for that card.
Alternatingly ASIO could be interesting but I haven't seen an ASIO
interface library for LabVIEW yet, although I was thinking about writing
one some time ago.
Rolf Kalbermatter
Love a Sheep wrote:
> That's a great help Sylvia but I am unsure how to call a library C
> function?
> I assume it is compiled in some way - how do I call this?
A manufacturere of hardware often delivers a so called DLL. You can use
the LabVIEw Call Library Node to call functions in a DLL. But without at
least some basic knowledge about C programming this is getting fast
quite difficult to understand and deal with.
In the case of Audio cards manufacturers usually do not provide
customized DLLs to call directly but instead drivers which plug into
standard system interfaces such as the Windows Multimedia API or for
more professional applications an ASIO interface.
> http://www.ltrpub.com/currentissue/
>
> which mentions the Audiophile 249
6 but even the .vis look different
> from LabVIEW 6.(In Figure 1 SO has a slightly different icon from
> normal and he only uses two inputs and outputs but does not say how he
> chose the correct two out of the four? Any suggestions?
This VI SO Set Num Buffers.vi is part of LabVIEW 7.0. LabVIEWs sound VIs
have been somewhat improved in LabVIEW 7.0. I think the library will
most probably select the two first channels automatically (also in 6.0).
The current Sound VI interface has no means to select specific channels.
At the time it was developed sound cards had a stereo input and output only.
Rolf Kalbermatter
> That's a great help Sylvia but I am unsure how to call a library C
> function?
> I assume it is compiled in some way - how do I call this?
A manufacturere of hardware often delivers a so called DLL. You can use
the LabVIEw Call Library Node to call functions in a DLL. But without at
least some basic knowledge about C programming this is getting fast
quite difficult to understand and deal with.
In the case of Audio cards manufacturers usually do not provide
customized DLLs to call directly but instead drivers which plug into
standard system interfaces such as the Windows Multimedia API or for
more professional applications an ASIO interface.
> http://www.ltrpub.com/currentissue/
>
> which mentions the Audiophile 249
6 but even the .vis look different
> from LabVIEW 6.(In Figure 1 SO has a slightly different icon from
> normal and he only uses two inputs and outputs but does not say how he
> chose the correct two out of the four? Any suggestions?
This VI SO Set Num Buffers.vi is part of LabVIEW 7.0. LabVIEWs sound VIs
have been somewhat improved in LabVIEW 7.0. I think the library will
most probably select the two first channels automatically (also in 6.0).
The current Sound VI interface has no means to select specific channels.
At the time it was developed sound cards had a stereo input and output only.
Rolf Kalbermatter
Love a Sheep wrote:
> I have been told by the manufacturers...
>
> Virtually all audio software on the PC uses one of the standard driver
> protocols, which include MME, WDM, and ASIO.
>
> Does that mean that it will work under LabVIEW?
The WDM driver is the kernel mode device driver accessing the hardware.
The MME driver I would assume provides the Multimedia API interface and
this is what the Sound VIs will access.
The ASIO is only provided for high end cards which have potential for
professional Audio use. There is no ASIO interface for LabVIEW that I'm
aware off. Writing one would involve external C code development.
Rolf Kalbermatter
> I have been told by the manufacturers...
>
> Virtually all audio software on the PC uses one of the standard driver
> protocols, which include MME, WDM, and ASIO.
>
> Does that mean that it will work under LabVIEW?
The WDM driver is the kernel mode device driver accessing the hardware.
The MME driver I would assume provides the Multimedia API interface and
this is what the Sound VIs will access.
The ASIO is only provided for high end cards which have potential for
professional Audio use. There is no ASIO interface for LabVIEW that I'm
aware off. Writing one would involve external C code development.
Rolf Kalbermatter
