REW Forum

**tonybradley** · **01-15-09, 11:57 AM**

Per the Picture found here:

http://www.hometheatershack.com/forums/attachments/spl-meters-mics-calibration-sound-cards/6692d1205433799-rew-cabling-connection-basics-rew-help-file-diagram.jpg

Is THIS the way you would hook up the system using a Soundcard Calibration File, or is this the method if you are doing the loopback in the cabling, where a loopback calibration file is NOT required?

EDIT: I see the remark for optional loopback, so I assume that is just a preference. Seems to me that doing that small hookup would take less time than running the loopback test and saving the file and loading it, etc. Any issues by using the extra loopback cable in this drawing?

**brucek** · **01-15-09, 12:28 PM**

Quote:

Is THIS the way you would hook up the system using a Soundcard Calibration File

No.

Quote:

or is this the method if you are doing the loopback in the cabling, where a loopback calibration file is NOT required?

Yes, and I don't personally recommend it. Use the soundcard calibration file method. Once the file is created, you're finished, and your testing will often be less noisy.

brucek

**tonybradley** · **01-15-09, 01:20 PM**

Once I do the loopback calibration, will the only change in the Cabling be the RCA cable from the Left to Left on the In and Out adapter, but keep everything else the same?

**brucek** · **01-15-09, 01:32 PM**

Select the right channel in REW and Connect a cable from the right channel line-in to the right channel line-out, and then do the soundcard calibration routine and save the file so REW can point to it.

Before removing this loopback cable, do a Check Levels and Calibrate SPL routine and do a measure of the loopback cable. If your soundcard cal file is correct, the resulting response graph will be a straight line.

Remove the loopback cable and use that right channel for your normal measurements. The left channel is never used.

Read and become familiar with the REW HELP files and the REW Cabling and Connections Basics.

Also note the REW information Index and the Download Page.

brucek

**tonybradley** · **01-15-09, 01:41 PM**

Great...thank you. I've been looking through some of those files today. I've looked at this about a year ago, but never attempted using REW, but am about ready to begin.

Off the wall question for this thread, but maybe you can point me to the area where this is answered. Does REW have a method that allows you to measure multiple seating locations, and then calculate the best EQ to get the flattest curve possible all those positions, or is this pretty much used for a Sweet Spot seating location? If the latter, do you EQ the Sweet Spot, then run REW at the other listening areas to see how the graphs look, then do all this again with the Sub at a different location, then compare the graphs of the various seating positions to determine which Sub Location can be EQd to give the best curve at multiple seating locations?

**brucek** · **01-15-09, 01:52 PM**

Quote:

Does REW have a method that allows you to measure multiple seating locations, and then calculate the best EQ to get the flattest curve possible all those positions

Yes, you take up to 8 measurements at the various listening positions and then on the Averaging tab, select the measures you want to include, and press the Average button. This will create a new average response graph that can be used by REW to create your filters for your equalizer.

To test the best location for a sub, the best method is to place the sub at one or various seating position and then move the mic around the room while running the RTA in REW.

brucek

**tonybradley** · **01-15-09, 04:22 PM**

Thanks Bruce. Last question until I get all the cables, connectors and get ready to start.

The pictorial shows one cable from the Line-out of the soundcard to the Aux or CD In, but says L or R. However, the information posted says that it's best to use a Y Splitter to the L and R of the Processor to test the Mains as well. At this point, I'm looking at doing the Sub only and maybe the Mains at a later time. Can I use just one RCA cable to the Aux In on my Processor? If so, is it best to use AUX or CD Input?

**brucek** · **01-15-09, 05:30 PM**

Quote:

Can I use just one RCA cable to the Aux In on my Processor? If so, is it best to use AUX or CD Input?

For sure you can just use one cable. The splitter is just a convenience to be able to check left or right or both without any fuss.

You can use any line input (Aux, CD, VDP, etc).

brucek

**tonybradley** · **01-16-09, 07:25 PM**

I was wrong, I have another cabling question. I have TONS of RCA cables that have come with DVD Players, Tuners, etc. over the years that I've never used. These are the typical thin RCA cables that come with purchased electronics. Would these suffice in this REW exercise, or should I purchase higher quality RCA cables for this purpose? I'm covered by for the Long runs, but can I use the cheaper RCA cables for any short runs?

**salvasol** · **01-16-09, 07:46 PM**

Quote:

tonybradley wrote:

I
I have TONS of RCA cables that have come with DVD Players, Tuners, etc. over the years that I've never used. These are the typical thin RCA cables that come with purchased electronics. Would these suffice in this REW exercise, or should I purchase higher quality RCA cables for this purpose? I'm covered by for the Long runs, but can I use the cheaper RCA cables for any short runs?

They will work fine ...you don't need to spend money on RCA cables

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