T/A setup with REW and USB mic

[Dwight]

Hi Guys, i really need some help here , i'm trying to do T/A with REW i keep failing..... setip: umik1 usb mic .... laptop with HDMI to A/V converter to HU as output and USB mic as input.... soundcard does have an aux mic input and an aux headset output. I cant figure out how to make that loopback i need to do T/A can you please help me out with how to configure REW settings. Banging head against the wall. Any help much appreciated

 

[John Mulcahy]

T/A meaning time alignment? A loopback cannot be used with a USB mic as the loopback and the measurement input need to be on the same device and the mic doesn't have any other inputs. For a USB mic you need to use the acoustic timing reference.

 

[Dwight]

Thank you for reply..... yes T/A =time alignment. This is what i've done..... are the settings ok? So what do i do with the results? How do i know which speaker is set to reference ? Red is left speaker and green is right speaker

 

[John Mulcahy]

How do i know which speaker is set to reference ?

Clues there would be the channel you have selected as the reference output and the "relative to acoustic reference on Master Volume L" text in the measurement notes

 

[Dwight]

Clues there would be the channel you have selected as the reference output and the "relative to acoustic reference on Master Volume L" text in the measurement notes

Yeah that was a stupid question, my english is bad. What i meant was how do i T/A other speakers to that speaker i choose? Should i switch to R when measuring the other speakers?..... cuz when i did both left en right in the graph the numbers arent correct time alignment Maybe im too stupid for this..... wts umik-1 mic

 

[John Mulcahy]

The same reference speaker should be used for all measurements, that way it remains consistent between them and their relative timing can be compared.

 

[John Mulcahy]

Note that it all makes sense only if you make all the measurements from the same mic position, of course. If the mic or the reference speaker move the timing is changed.

 

[Dwight]

Thnx for reply..... yes i understand that and that is excacyly what i did. Mic was 90degeee where my head should be. I dis a sweep with those settings for left speaker (red) and then sweep for right speaker (right) (should i use the exact same settings when i measure both speakers? now i see the notes and i use math to get the difference but when i put that in de dsp is does not sound T/A. When i use measument tape now..... the left speaker to the mic is 52inch and right speaker to mic is 38inch.... so the differnce should be 14inch right? But i dont get that number at all using rew..... so to my under standing im not doing it the right way with rew. Im prolly need a step by step guide i get the feeling my IQ is negative :s

 

[Dwight]

Note that it all makes sense only if you make all the measurements from the same mic position, of course. If the mic or the reference speaker move the timing is changed.

Im so sorry my i'm not an english speaking guys , so i cant really explain my problem proper.... otherwise you wouldve helped me by one reply

 

[John Mulcahy]

From your image both speakers were selected for output ("L+R"), the output should be just L when measuring the left speaker and just R when measuring the right. REW will automatically send the timing signal to the selected reference whatever the measurement output is.

 

[Dwight]

From your image both speakers were selected for output ("L+R"), the output should be just L when measuring the left speaker and just R when measuring the right. REW will automatically send the timing signal to the selected reference whatever the measurement output is.

Now that is what my stupid brain needed..... thnx ill try it that way and hopefully i can finally make it work

 

[Dwight]

Now that is what my stupid brain needed..... thnx ill try it that way and hopefully i can finally make it work

Did what you suggested but the number dont add up again :s

 

[Dwight]

From your image both speakers were selected for output ("L+R"), the output should be just L when measuring the left speaker and just R when measuring the right. REW will automatically send the timing signal to the selected reference whatever the measurement output is.

Thank you.......I finally got it to work i think.... question now is how do i measure other speakers on the left side of the car when i use Left as reference? Should i use RIGHT inputs on the dsp through those speakers instead of LEFT?

 

[Dwight]

Tha

From your image both speakers were selected for output ("L+R"), the output should be just L when measuring the left speaker and just R when measuring the right. REW will automatically send the timing signal to the selected reference whatever the measurement output is.

From your image both speakers were selected for output ("L+R"), the output should be just L when measuring the left speaker and just R when measuring the right. REW will automatically send the timing signal to the selected reference whatever the measurement output is.

thank you for putting up with me...... i finally nailed it!! now for my understanding time alignment alone isnt the whole proccess..... now i need to get all the speakers up to the same Dicbel level right? How can i achieve that with rew? Whats the best methos? For example i got my left and right speaker aligned with rew procces. But now the right speaker should be DB reduced to play same level as left speaker. Help would be appreciated again

 

[John Mulcahy]

You could play a pink PN speaker cal signal through left and then right and trim the levels for the same SPL meter reading, or eyeball the graphs and use the trace offset feature to see what dB shift gives what looks like the best level alignment and then adjust the gain by that amount

 

[Dwight]

You could play a pink PN speaker cal signal through left and then right and trim the levels for the same SPL meter reading, or eyeball the graphs and use the trace offset feature to see what dB shift gives what looks like the best level alignment and then adjust the gain by that amount

Thnx alot bro