REW: Stuck making first measurement

[PhilipW]

First REW Install.

Equipment:

Galaxy CM-140 SPL meter
ECM8000 calibrated mic from recent offering
Xenyx 802 preamp

I've been following the documentation / help files and have calibrated my sound card with the loopback cable. Set it to -18db and matched it to -18db, both left and right channels. Created the calibration file and saved it.

I downloaded and used the Galaxy calibration file. I have also used the Galaxy SPL meter to calibrate the speaker output, which came in at 75.2db at listening position with my receiver at -10db on the volume knob. I pointed the SPL meter up facing the speakers. Is that correct?

I set up the preamp / mic per provided photos and connected it per help file instructions, but when I check levels in the Make a Measurement Panel, I get -18 in the input and no signal indication on left or right, and a Level is Low -99.0db warning. A side question, where should the mic be positioned? I couldn't find this referenced anywhere. I have it at listening position vertically, label to front.

I went back and started from the beginning again with all settings / calibrations and still same resultes.

I also tried to hook the output from the SPL to the soundcard input, and no level still. I didn't see this exact use documented other than the connection drawing, so I hope this was ok to try.

I'm guessing I'm overlooking something basic here so any help would be great.

[brucek]

have calibrated my sound card with the loopback cable. Set it to -18db and matched it to -18db, both left and right channels. Created the calibration file and saved it.

Let's start here. Why do you have signal on the left and right channel when the calibration routine for a soundcard only uses a single loopback cable from the right channel line-out to the right channel line-in (assuming you selected right)?

brucek

[PhilipW]

brucek wrote:

Let's start here. Why do you have signal on the left and right channel when the calibration routine for a soundcard only uses a single loopback cable from the right channel line-out to the right channel line-in (assuming you selected right)?

brucek

The instructions aren't specific on this point. It just says connect the line output directly to its line input. I used a stereo cable for it assuming it would discard the extra channel if unnecessary. Later, all other connections are done splitting off one channel with a 1/8 to rca breakout adapter as this part was specific in the help files.

[brucek]

The line-in and line-out both use splitters so that you can feed the right channel line-in with the mic preamp, and the right channel line-out will feed your receiver. To ensure these are both working properly, use them to create the soundcard calibration file with a single loopback cable. If the file creates properly, then you know you're good to go. The left channel is left open.

Once that's completed, remove the loopback and connect the mixer main out to the right channel line-in and connect the mic to the mixer. Be sure to turn on the phantom voltage and be sure the VU meters on the mixer indicate a decent level when you sing into the mic.

Connect the soundcards right channel line-out to your receiver AUX or CD in.

You're ready to calibrate REW now....

brucek

[PhilipW]

brucek wrote:

The line-in and line-out both use splitters so that you can feed the right channel line-in with the mic preamp, and the right channel line-out will feed your receiver. To ensure these are both working properly, use them to create the soundcard calibration file with a single loopback cable. If the file creates properly, then you know you're good to go. The left channel is left open.

Once that's completed, remove the loopback and connect the mixer main out to the right channel line-in and connect the mic to the mixer. Be sure to turn on the phantom voltage and be sure the VU meters on the mixer indicate a decent level when you sing into the mic.

Connect the soundcards right channel line-out to your receiver AUX or CD in.

You're ready to calibrate REW now....

brucek

Thanks. I am changing to splitters, though haven't yet been able to get output on either left or right yet for some reason. Can change to the stereo cable and it works fine, change back to splitter, nothing. Will keep working on this now.

[PhilipW]

I have calibrated the soundcard now using only the right channel.

I have loaded the galaxy spl meter config and checked the level using the mains and set the level to 75.1db.

I moved onto taking a measurement, but again I have the same level is low warning, 87.8db. There is no indication in REW that either the right or left channel is receiving any signal.
I have plenty of volume coming out of the speakers, 96db+. I have checked and rechecked the configuration of the mic / pre amp and wiring and it's all good. phantom button is pressed. snapping my fingers makes the preamp vu leds light up on the right channel. I'll review the connections...: mic connected to a 30' xlr cable. The mic is at listening position mounted vertically, with the label pointed to the speakers. (not sure if this is right). The xlr cable is plugged into the left hand connection on the pre-amp. All the settings on the pre-amp are set per the help file photo. Output is trough a 1/4" mono jack with female rca connector that has a 20' rca patch cable plugged into it. that's connected to the right channel of a 1/8" mini phono jack and that's plugged into the line in on the computer.

[brucek]

I moved onto taking a measurement

But did you move onto this step before running Check Levels routine and Calibrate routine?

that's connected to the right channel of a 1/8" mini phono jack

That is a stereo 1/8" phono adapter I hope?

The mic is at listening position mounted vertically, with the label pointed to the speakers.

Vertical with a 10-20 degree angle toward the main speakers. (label? - matters not).

Anyway, forget about REW and plug the preamp (using the 1/4" mono jack with female rca connector that has a 20' rca patch cable) into your receiver AUX or CD input and get some sound through the mic first.

brucek

[PhilipW]

brucek wrote:

But did you move onto this step before running Check Levels routine and Calibrate routine?

Yes, I thought I said that in my first two sentences? "I have calibrated the soundcard now using only the right channel. I have loaded the galaxy spl meter config and checked the level using the mains and set the level to 75.1db." Sorry if I wasn't clear I started over.

brucek wrote:

That is a stereo 1/8" phono adapter I hope?

Yes. Stereo 1/8" with red and white rca pigtails on it. Red being the right channel.

brucek wrote:

Vertical with a 10-20 degree angle toward the main speakers. (label? - matters not).

brucek wrote:

Anyway, forget about REW and plug the preamp (using the 1/4" mono jack with female rca connector that has a 20' rca patch cable) into your receiver AUX or CD input and get some sound through the mic first.

Plugged into the aux input and , that generated was the worst driver breaking noise I've ever heard. I dropped volume as quickly as possible and have brought it back up slowly now. I do get sound from the mic to the speakers now. I assume this means there's an issue getting sound into the card and to REW that has to be sorted out. I spent quite a bit of time on that already, but will go around again checking everything. Will also see if you have any more thoughts on it.

[brucek]

I assume this means there's an issue getting sound into the card and to REW that has to be sorted out.

Yeah, but since you were able to do the soundcard calibrate routine, (which verifies that the adapters and signal levels are all working), this is quite a puzzler. You have proven that the mic preamp is outputting a signal, so when you plug it into the line-in there should be a signal.

Can I see a picture of the REW settings page? And also a picture of the Windows playback and recording mixers?

brucek

[PhilipW]

brucek wrote:

Yeah, but since you were able to do the soundcard calibrate routine, (which verifies that the adapters and signal levels are all working), this is quite a puzzler. You have proven that the mic preamp is outputting a signal, so when you plug it into the line-in there should be a signal.

Can I see a picture of the REW settings page? And also a picture of the Windows playback and recording mixers?

brucek

I ran through everything again and took screen captures. Here you go:

REW Screen Captures