Digital out

[bob1]

Simple question really can i use digital out from my sound card for REW, i haven't tried anything yet its just that i have the lead in place and wandered if it will do the job ok.
Thanks.

[Otto]

The short answer is "you can." The reason to use analog I/O is to be able to measure your soundcard's response, so that you can account for it in the measurement. You do that via the soundcard cal in REW.

I have measured my soundcard using analog I/O. I have then used a digital input and an analog output, and measured much the same response, so that tells me that my soundcard's response is coming mostly from the input of the soundcard rather than the output.

Poke around at it a little from both sides and see what works for you. Certainly, if you just want to get things going and see how they work, a digital input to your system is a viable option.

[bob1]

Thanks for the quick reply,i can always make an adaptor and do analogue if i have problems .I need to make a lead now for the meter as its not long enough, then i can start to play.

[bob1]

Looks like i will have to try analogue out from the pc ,the levels seem too high all the time ,i calibrated the sound card fine but when i come to do the other levels there just not right ,i could be doing something wrong though.

[Otto]

Hey bob,

Where are the levels too high? When you measure with the SPL meter? There are a couple places you can turn down, so we should be able to get there somehow.

[bob1]

Yes when i measure the SPL meter, when i think its right and i'm going for a reading its says it too loud ,i turn it down but it seems too quiet to get a proper reading.I have given up for now and wil have a go when i get another chance ,i have a graph but didn't put the corrections in for the sound meter i used the sound card corrections,no wander there's so many smiley's to say you don't know what to do.

[Otto]

If the test tone is measuring 75 dB (or so) with the SPL meter, did you calibrate REW's input meter to match?

Here's a picture:

AnnotatedCalibration.jpg

[bob1]

Ok thanks ,i missed that one , i will try again later.

[Hakka]

I tried the optical out on my Behringer UCA 202 a while back and as soon as I started the sweep the AVR shut itself down. I didn't try again.

Hakka.

[bob1]

Still doesn't work as it should done soundcard ok ,done meter levels ok but when i come to do a sweep it says level too high all the time,i can only think its because of the sound cards output being totally different between digital and analogue.
Looks like it will be the weekend before i can try it again.
Any advice in the mean time would be good.
Thanks.

[brucek]

,i can only think its because of the sound cards output being totally different between digital and analogue

I don't see that being a problem even if it was indeed at a different level, because it would be compensated for in the setup.

In the Settings screen when you run the Check Levels routine, you first adjust the RS SPL meter at the listening position to 75dB with the REW output level and the receiver volume control. Then you adjust the REW input level to the correct level.

Then you run the Calibrate SPL routine in REW to match that 75dB level.

That's it, it's all at the correct level. The only problem after that would be that you don't have the End Frequency adjusted in the Measurement routine screen matching the pink noise cutoff frequency in the Check Levels routine in the Settings screen.

If you do a Check Levels in the Settings routine for a subwoofer, the hi-cut on the pink noise is 80Hz. If you set the End Frequency in the Measurement routine to (for example) 400Hz and tested the Check Levels there, you would get an incorrect reading on the levels. Be sure the upper End Frequency in the Measurement routine is at 200Hz.......

brucek

[bob1]

I have now tried analogue and it doesn't work as i'm getting feedback ,i don't have an option to turn the monitoring off so it looks like digital is my only option.

What is REW input/output level ,is this your line in/line out volume on the pc, it doesn't give me the option in REW there blanked out.
I'm sure its easy when you know how .

[brucek]

What is REW input/output level ,is this your line in/line out volume on the pc

Check the two Control boxes and REW will have control. These set up the levels in the Check Levels routine. If not, then use the PC mixer to control the input / output level.

What did you use to set the levels in the Check Levels routine?

check levels.jpg

brucek

[bob1]

Thanks for the Attachment ,i now have the the settings to adjust which i didn't have before ,i will give it another go tomorrow.
Thanks for your help so far.

[bob1]

Managed at last, i don't have a bfd i sold that with my last sub,i used the on board peq to tame the main peak, sub is a Svs sb12+ .
Thanks for the hepl .

[brucek]

Pretty good response. The peq seemed to do the job on the peak. I'm sure the 20Hz area is much better as a result. Did you check how the mains integrate with the sub?

brucek

[bob1]

I haven't done the mains in with it yet ,that will have to be at the weekend now.
I had the peak tamed pretty good before but not quite in the right place REW makes using the peq much easier.