Help Measuring Impulse & Phase Of An Audio System With No Analog Input

skizer

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Hello everyone, I'm needing a bit of help with the measurement of timing and phase in a vehicle's OEM sound system so I have the data to properly integrate into it. Unfortunately, there is no AUX input in many cars these days, so I have to do this a bit differently. I am familiar with the offline measurements, but 2 things. First, I'm not sure how I would go about recording a sweep. Can you record this with REW or do I need a different software? Second, is there any way I can skip the whole recording part and just measure it directly into REW? Any help is greatly appreciated. Thanks!
 

dotnet

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If the audio system doesn’t have any inputs (analog or digital) and can only playback media from CD or USB stick, you can record measurement sweeps incl. timing reference and play them back for REW measurements. In the Generator tool, you can record measurement sweeps to file, and in the Measure tool you can wait for them to be played.
 

skizer

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If the audio system doesn’t have any inputs (analog or digital) and can only playback media from CD or USB stick, you can record measurement sweeps incl. timing reference and play them back for REW measurements. In the Generator tool, you can record measurement sweeps to file, and in the Measure tool you can wait for them to be played.
Yes, so how do I record these?
 

dotnet

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Yes, so how do I record these?
With a microphone attached to the computer REW is running on. If you’re not interested what comes out of the speakers and only want to see what the amps produce, you need to connect the amp output to an audio interface (ADC) connected to the computer REW is running on.
 

thothsong

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Yes, so how do I record these?
Do you mean how do you take measurements, or do you mean how do you create the sweep file to play? If you mean create the sweep file, you don't "record" it, you generate it using REW. Open the Generator window, select the Sweeps tab, choose Measurement, and the start and end frequencies and length that you want, then click Save to file, choose the channel(s), and click the WAV button.
 

skizer

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I have all of that stuff. I have the mics, the interfaces, the knowledge on how to use them, etc, but I've just never done this exact thing using REW. I measure electrical signals in cars all of the time, but usually just with RTA. I made the sweeps, I managed to record with audacity, but I feel it adds unnecessary steps and I may be missing a way to just record it directly into REW. Is this possible? I think Johns link answered that question. I will give this a shot. Thanks!
 
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