Question Request: ASIO Sound Card Help

[mrgrey]

I currently have two input devices:

(1) The microphone built into my laptop.

(2) An USB external mic.

I want to record both devices simultaneously, therefore I believe I need an ASIO sound card.

My system is a Dell XPS laptop. When I look at my sound in the DirectX diagnostic tool, it says I have Realtek(R) Audio. In device manager, my microphone description is simply Microphone Array (Intel Smart Sound Technology Digital Microphones).

Basically, I assume that the builtin sound card on my laptop may not support ASIO. So I assume that I need to buy a USB ASIO sound card, which is fine if I do.

But one of the two listening devices I have is the laptop's microphone array. So... can a USB external ASIO card read the internal array from the laptop? Or if not, what should I do?

 

[Corwin65]

Can you explain why you need to record both sources?

This will let me formulate an answer.

 

[Paperdoc]

If I understand correctly an ASIO sound card uses a particular non-standard software interface system to bypass the common ways of processing audio signal on a mobo and reduce time delays or latency in the processing. You are not saying you have a latency problem, so I'm not sure you need that particular feature. More importantly, just because it is unique and may offer some fancy features does NOT mean it can do more unusual things than a "normal" sound card.

In general, any add-on sound card - and in your case, it MUST be an external unit connecting via USB, presumably - has NO way to access a microphone built into your system and permanently attached to some mobo audio processor chip. So NO, that will NOT allow you to use that built-in mic AND an external mic at the same time. If you NEED to use two mics and mix them together you need two EXTERNAL mics and some form of audio mixer to blend their signals together into a single audio signal for input to your laptop's single Mic input. Then in your laptop's sound system you tell it to use that external signal (rather than the built-in Mic) as the Default Sound Source.

 

[mrgrey]

If I understand correctly an ASIO sound card uses a particular non-standard software interface system to bypass the common ways of processing audio signal on a mobo and reduce time delays or latency in the processing. You are not saying you have a latency problem, so I'm not sure you need that particular feature. More importantly, just because it is unique and may offer some fancy features does NOT mean it can do more unusual things than a "normal" sound card.

In general, any add-on sound card - and in your case, it MUST be an external unit connecting via USB, presumably - has NO way to access a microphone built into your system and permanently attached to some mobo audio processor chip. So NO, that will NOT allow you to use that built-in mic AND an external mic at the same time. If you NEED to use two mics and mix them together you need two EXTERNAL mics and some form of audio mixer to blend their signals together into a single audio signal for input to your laptop's single Mic input. Then in your laptop's sound system you tell it to use that external signal (rather than the built-in Mic) as the Default Sound Source.

Ok, that's more or less what I was looking for. So it looks like I do need a second external mic. Further, I think the latency may matter. Thank you for the suggestion.

To answer the previous question, I have a sound system that I have discovered is outputting inconsistent amplitude signals. So I'll play a tone and measure (using my single current mic), and for some reason every other tone is louder, while the alternating tone is quieter. I'm looking for the cheapest solution to measure the amplitude of the output accurately. My application only requires relative amplitude recordings - so if I have two mics, one preferentially located in my application space and a 2nd located right next to the speaker, then I can normalize to the speaker output and the alternating tonal emission can be normalized away.

I was trying to get away with the cheapest solution and was thinking my laptop already has a mic, so why not use that? But I think the timing matters. I simply want to record on two channels that are separated in space - not mix them together. But I also need to ensure I record the same signal simultaneously - the lag between the speaker and application space is trivial, but is the recording lag trivial? That's my uncertainty.

 

[Paperdoc]

When you try to record the same signal (or ones that ought to be completely synchronized) using two very different channels for pickup (mic, amplifier, digitizer, and data transmission to recording on disk), most certainly there CAN be a time lag difference that IS significant. That does not mean it WILL be bad, but it can be. Your best bet to minimize that is to use ONE system that operates on two identical processing channels so that any time delays are virtually identical. That is why an external mixer and two identical mics feeding it would to your job best. I expect you are trying to work in two separate stereo audio channels, so of course you would need a stereo mixer. But here's an important item when you do this. It is typical that the MIC input on your computer MAY be set up to use only a mono (single audio channel) input. Thus connecting the output of a stereo mixer to the Mic input may NOT be the right way. Connect the mixer instead to the stereo Line In socket on your computer. It is designed for 2-channel stereo input at the standard "Line In" voltage and impedance ratings, so you would get optimal signal quality and BOTH channels done properly.

IF you might need two inputs (mics) on ONE stereo channel, ensure that any mixer you get has more than one input connection on EACH stereo channel.