REW setup question

[GregBe]

OK, I know this has been asked a million times, and I have read the help files a few times. Maybe I am just a little dense, but have a few questions.

I don't have an EQ yet. I do have a SVS PB12+, with a one band eq, I plan to use REW to first find the best location for my sub, and then to see which port tune mode to set the SVS to, and then to set the EQ and phase.

I just picked up a Soundblaster MP3+ for $5 from someone locally, so I figured I would give this a shot. So if I don't have a bfd setup, I simply run one RCA from the SPL meter to the soundcard, and one RCA to the receiver, and run the program in stereo mode on my receiver with the sub on to measure the response of the mains and the sub? Is that right? I see a lot of splitters and such. Do I need them?

Thanks
Greg

[brucek]

I simply run one RCA from the SPL meter to the soundcard, and one RCA to the receiver, and run the program in stereo mode on my receiver with the sub on to measure the response of the mains and the sub? Is that right? I see a lot of splitters and such. Do I need them?

I believe the MP3+ uses separate RCA left and right for line-in and line-out, so adapters to break out the channels isn't required. You should use a splitter at the receiver to split the mono signal to the left and right input of the AUX or CD channel though.

Before you make any connections you need to use a loopback and create a soundcard calibration file. Then remove the loopback and use that channel to measure with.

brucek

[GregBe]

Thanks Bruce. You are right the MP3+ does have separate RCA L and R In and Out. So basically, I would go from RS SPL meter to R input of soundcard with one RCA cable. Then go from R ouput of soundcard to receiver with a single RCA cable, with a splitter at the end to input both a left and right signal to the receiver input so I can operate the tones in stereo out of both speakers and sub as well. No additional splitters would be needed except the one into the receiver.

For the loopback, I would in addition to the above connections, connect one RCA cable from the Soundcards L input to the soundcards L output. Once I calibrate the soundcard and the SPL meter, I can remove the loopback RCA cable, and pretty much would not need that anymore.

Does this sound about right?
Thanks!!!

[brucek]

So basically, I would go from RS SPL meter to R input of soundcard with one RCA cable. Then go from R output of soundcard to receiver with a single RCA cable, with a splitter at the end to input both a left and right signal to the receiver input so I can operate the tones in stereo out of both speakers and sub as well. No additional splitters would be needed except the one into the receiver.

Yes, except the signal coming from your mains would not be stereo. It is a mono signal coming from two speakers. You do have to have your receiver in stereo mode though, with all soundfields off.

For the loopback, I would in addition to the above connections, connect one RCA cable from the Soundcards L input to the soundcards L output. Once I calibrate the soundcard and the SPL meter, I can remove the loopback RCA cable, and pretty much would not need that anymore.

No, the loopback cable goes from right channel line-out to right channel line-in. The soundcard calibration is run, and the file saved. The loopback is removed and that calibrated right channel is used to measure. The left channel is never used.

brucek

[Eric D]

brucek wrote:

....No, the loopback cable goes from right channel line-out to right channel line-in. The soundcard calibration is run, and the file saved. The loopback is removed and that calibrated right channel is used to measure. The left channel is never used.

brucek

I'm just starting out with REW too. Is a calibration file considered more accurate than using the left channel as a calibration reference?

tia,

[brucek]

Is a calibration file considered more accurate than using the left channel as a calibration reference?

The calibration file is much easier to use. Uses less cabling. Vets any problems before you start.

Use the calibration file method.

brucek