Getting setup to run REW....

**Ryan_M** · **06-09-09, 03:34 PM**

I've read the connections section and I do understand what's being connected to what and why but it doesn't match my particular setup so I'm a little confused.

My setup for both music and HT is run off of a HTPC running Vista Media Center. I connect from the onboard sound (Asus P5E-VM HDMI mobo) to a HK AVR-235 with digital coax. Now I guess first thing would be how do I do the soundcard calibration? I'm assuming I would want to include any effects the HTPC and AV receiver's XO has on the signal so would I loop back the SUB_OUT on the AVR to the soundcard input on the HTPC or set the mains to "large" and use that so the soundcard will see the entire audio spectrum?

Thanks for any help,
Ryan

**brucek** · **06-09-09, 04:18 PM**

What are you trying to accomplish?

Are you attempting to create a convolver DSP audio plug-in for Windows?

Have you visited the convolver thread.

brucek

**Ryan_M** · **06-09-09, 05:37 PM**

I'm trying to setup my sub and see how well it transitions over to my mains, or at least just get a plot at this point.

Never heard of convolver but I'll go check it out.

**brucek** · **06-09-09, 06:51 PM**

Quote:

I'm trying to setup my sub and see how well it transitions over to my mains

Great, then forget that your PC is an HTPC and use it as a simple tool to run REW and refer to the standard connection diagram.

Use the PC soundcards analog line-out and line-in and create the soundcard calibration file and use those ports (once calibrated) to plug your meter into and feed the AVR.

brucek

**Ryan_M** · **06-09-09, 07:18 PM**

Using the analog audio out from the PC adds:

- a DAC in the HTPC
- an analog stage in the HTPC
- an analog stage in the AVR
- a ADC in the AVR

extra to the signal path that wouldn't normally be there. So I'm OK to assume that after the signal goes through all those extra steps it will emerge at the SUB-OUT of the AVR with the same frequency response as if it weren't there? or are the differences minimal enough that they can be ignored?

**brucek** · **06-09-09, 07:29 PM**

Quote:

Using the analog audio out from the PC adds:

Remember that you're creating a calibration file for the analog loop in the soundcard that renders it flat. This negates the differences in the HTPC.

The differences in the AVR wouldn't even come close to the difference in moving the mic a few inches when measuring.

Since you appear quite concerned about precision, I assume you're using a professionally calibrated microphone?

brucek

**Ryan_M** · **06-09-09, 07:59 PM**

Quote:

brucek wrote:

Remember that you're creating a calibration file for the analog loop in the soundcard that renders it flat. This negates the differences in the HTPC.

Good point.

Quote:

brucek wrote:

The differences in the AVR wouldn't even come close to the difference in moving the mic a few inches when measuring.

This was what I was wondering.

Quote:

brucek wrote:

Since you appear quite concerned about precision, I assume you're using a professionally calibrated microphone?

I wouldn't say I'm that concerned with precision, I just didn't know how the extra equipment would affect the test. It appears I'm making much ado about nothing.

FWIW I'm using an ECM8000 and a MIC800, hardly professional I'm assuming considering what it costs. The mic isn't calibrated though I would like to as soon as I find a place locally to do it. I just got it a few days ago so I haven't really looked too far into it.

Thanks for the help Bruce!
Ryan

**brucek** · **06-09-09, 08:27 PM**

Quote:

I'm using an ECM8000

We provide a generic cal file for it on our download page. We have a bit of info there on the accuracy of using the generic file. Generally, it's fine for home use.

brucek

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