# Tascam US-144MKII for signal output for time alignment setting



## edouble (Sep 5, 2012)

I am will be using a Tascam US-144MKII, laptop and Dayton Audio EMM-6. To properly measure and set the time alignment of the speakers in my vehicle can I use the "line out" on the Tascam US-144MKII to the input on my head unit? My microphone will be connected into the "mic in" on the Tascam US-144MKII.

Please excuse my lack of understanding this!


----------



## edouble (Sep 5, 2012)

Highlighted below is why I am using an output from the Tascam US-144MKII as a "loopback" from REW. *What I do not know is if the signal generated by REW will go to the Tascam US-144MKII through USB and then from the Tascam US-144MKII to my head unit via the "line out" on the Tascam US-144MKII. *




_The Use Loopback as Timing Reference selection controls whether REW uses a loopback on the soundcard as a timing reference for the channel being captured, to eliminate propagation delays within the computer and soundcard. The reference channel signal must be looped back from output to input for this option to work. If this is not checked REW will set the IR zero time according to the setting of Set t=0 at IR Peak.

If using a loopback as a reference REW can calculate the delay through the system being measured and show it in the measurement Info panel as "System Delay" in milliseconds, with the equivalent distance in feet and metres shown in brackets. Note that delay values are not accurate for subwoofer measurements due to the limited bandwidth of the subwoofer response, the delay estimate is based on the location of the peak of the impulse response and subwoofers have a broad peak and a delayed response._


----------



## jtalden (Mar 12, 2009)

Yes that's correct.

The REW test signal goes to the Tascam over the USB. 
The Tascam line out connects to the head unit.
The mic signal from the Tascam travels back to REW over the USB.
The loopback signal on the other channel also travels back to REW over the USB.


----------



## edouble (Sep 5, 2012)

jtalden said:


> Yes that's correct.
> 
> The REW test signal goes to the Tascam over the USB.
> The Tascam line out connects to the head unit.
> ...


Great. Thank you for the reply!


----------

