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Discussion Starter · #1 ·
I am trying to set up Smaart for the first time for measuring my car audio system for tuning my dsp. I have a two channel audio interface, my laptop and XLR measurement Mic and I’m trying to figure out how to correctly wire/set up for real-time measurements for phase and time. I believe that I need to create a loop back but I am having a hard time finding an example that shows the configuration for car audio system application. Can somebody who using Smaart or similar show me how to wire it up properly. Drawing a diagram or a picture of their set up with explanation would be super appreciated. Thanks in advance
 

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Have you already gone through the REW primer for calibrating your sound card and microphone where a loopback connection is necessary?

Not that measuring Frequency Response and timing is the same just making sure you are familiar with the loopback function.

For reference the REW Author is still active on AV Nirvana: John Mulcahy
 

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I am trying to set up Smaart for the first time for measuring my car audio system for tuning my dsp. I have a two channel audio interface, my laptop and XLR measurement Mic and I’m trying to figure out how to correctly wire/set up for real-time measurements for phase and time. I believe that I need to create a loop back but I am having a hard time finding an example that shows the configuration for car audio system application. Can somebody who using Smaart or similar show me how to wire it up properly. Drawing a diagram or a picture of their set up with explanation would be super appreciated. Thanks in advance
Did you get this sorted? I can 100% help if not! I’m hoping you have sorted it

Drop me a pm if you like or we can do it here for the benefit of everyone 👍🏼
 

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I am trying to set up Smaart for the first time for measuring my car audio system for tuning my dsp. I have a two channel audio interface, my laptop and XLR measurement Mic and I’m trying to figure out how to correctly wire/set up for real-time measurements for phase and time. I believe that I need to create a loop back but I am having a hard time finding an example that shows the configuration for car audio system application. Can somebody who using Smaart or similar show me how to wire it up properly. Drawing a diagram or a picture of their set up with explanation would be super appreciated. Thanks in advance
What 2-channel audio interface are you using and what inputs are you using on your DSP (analog or digital)? There is multiple ways to wire this up and it is basically the same thing whether it is car audio DSP or pro audio gear.
 

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Lexus IS250 -Eton Stealth 7.1 dsp/amplifier_Dynaudio -MB_Xcelsus-mid_JL Audio c5-tw_Arc Black 12d2
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Discussion Starter · #5 ·
I'm using a Roland Edirol ua-25. I am running a 1/4" from input 2(right) on the front to output 2(right) on the back for loopback. Then I have a measurement microphone hooked up to input 1 (left) on the front. For the other output on the backside, I have an adapter that goes from 1/4"> 2 FEMALE RCA > RCA to 1/8"> OEM head unit aux input. For some reason, I feel there is a better way. I want to be able to do time and phase measurements.

I don't have my interface wired directly to DSP. I have an arc audio ps8-50 and a minidsp ddrc with Dirac upstream. Running an optical cable from PAC audio amp pro to DSP.
 

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Well i am not dumdum but here is a simple diagram.

Font Technology Electronic device Rectangle Audio equipment


The transfer function measurement is always comparing a refence signal (loop back) to the mic signal in our case. the reference signal needs to loop back into the measurement device and be sent to your rig at the same time.

Time and phase will be relative to where you tap into the system and then out through the speakers to your mic. You have to decide what part of the signal chain you want to measure or put another way include in your measurement.

This is always a single channel ( tweet, mid or what ever speaker ) relative to the reference signal. The RCA output needs to be moved to what ever side left or right you are measuring.

I suggest you go to the Rational Acoustics site and walk through their very excellent training videos as a guide.

Hope this helps you out :)
 

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You can combine speaker outputs for relative phase overall measurements at some point when you have the individual drivers where you want them (T/A) delay wise. Matching left and right sides and what not.
 

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In SMAART input 1 is the REF signal assignment and Input 2 is the measurement channel, with the setup above. That creates the 2 channel measurement setup from a connection and configuration perspective. The Sig gen is assigned to Output 1 in the setup and if you have USB audio configuration software SMAART is assigned as the DAW (digital audio workstation) output channel and is connected to output 1 in the USB audio device. In my Focustite i have to set this part up (output channel mappings and mixing) but you may not need to.
 

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You do have the option to use the toslink (digital output) into your system if you want. this may add more confusion for you i do not know. But to do that you will need to create a virtual loop back channel in the Roland that loops back the DAW output channel (smaart) and also run the signal to the toslink output. at the same time. This is what i do in my setup except i use COAX and not toslink as my preferred connection to my DSP directly.

The reference channel mapping will now be switched to the virtual loop back channel in the SMAART I/O configuration. The mic channel stays the same.

Perhaps start simple with RCA output to your system input and get things working and practice measurements before the added complexity of using the digital output. Up to you. Both will work if Roland supports virtual loopback channel configurations.
 

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I'm using a Roland Edirol ua-25. I am running a 1/4" from input 2(right) on the front to output 2(right) on the back for loopback. Then I have a measurement microphone hooked up to input 1 (left) on the front. For the other output on the backside, I have an adapter that goes from 1/4"> 2 FEMALE RCA > RCA to 1/8"> OEM head unit aux input. For some reason, I feel there is a better way. I want to be able to do time and phase measurements.

I don't have my interface wired directly to DSP. I have an arc audio ps8-50 and a minidsp ddrc with Dirac upstream. Running an optical cable from PAC audio amp pro to DSP.
Assuming PAC amp pro gives a flat output… I’d measure an output from the dsp to be sure… I would just insert the signal direct into the dsp as analogue and have at it, you can make up a 3.5 to two 1/4” jacks so you don’t have to use two outputs… my ocd says use one incase there are differences

aside from that you are good to go

drop me a pm if you want a hand negotiating smaart and reading results etc

I’ve helped a fair few people out with it via various methods 👍🏼
 

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Discussion Starter · #12 ·
Thanks for all the help. I am going to spend some time working on it this weekend. I watched some of the videos on the rational acoustics website as you suggested last night, which helped too. I will let you know how it goes. I am sure there will be more questions to come. thanks again guys and gals for taking the time to respond to my questions. aDo you think it would suit me better to get a newer interface? would it make a difference? I was looking at the Roland quad capture and the Scarlette 2x2
 

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Thanks for all the help. I am going to spend some time working on it this weekend. I watched some of the videos on the rational acoustics website as you suggested last night, which helped too. I will let you know how it goes. I am sure there will be more questions to come. thanks again guys and gals for taking the time to respond to my questions. aDo you think it would suit me better to get a newer interface? would it make a difference? I was looking at the Roland quad capture and the Scarlette 2x2
As long as your interface works it should be fine. I would only upgrade if you cannot get good stable measurements and/or you want more features and input channels at some point.
 

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Sorry for a newbie question, let's say I have all the equipment and cables - how to connect everything to Fiio M11 (my source) and minidsp 8x12? I use coax 3,5 to dsp.
You don’t need the source, just setup a preset with one analogue input to all channels and mute/ un mute channels as required and take readings of whichever channel you want to measure

the fiio via coax will give a flat output so what you get from a decent interface will mimic this as a signal anyway 👍🏼

I use coax from an iPad and analogue into the system from a Scarlett 2i2 and results are consistent
 
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