Hi Everyone,
I'm working my way through the steps to use REW, and I've run into something that I don't understand. Here's a summary of where I'm at:
1) I have a Creative Labs "Blaster X-fi" external sound card. This card has separate right and left channels for line out. It has a single connector for line in.
2) I'm using a Radio Shack digital SPL meter.
I believe I have done the sound card calibration properly. I set up the cables as shown in the first attachment.
On this picture, I ran the right line output from the sound card to the right side of the splitter plugged into the sound card's line in. I believe that this Radio Shack Connector splits out left and right signals from the single pin. The picture shows a second splitter which is identical to the one plugged into the sound card for reference.
The second attachment is the sound card's uncorrected response. The corrected response is completely flat from 2 - 24Khz. I don't have a jpeg for this graph.
So am I on track as far as the setup and procedures for calibrating the sound card ?
I think I have done all of the steps correctly, but when I go to the acutal measurment phase of the process, I'm running into something I don't understand, so I thought it's possible that I've done something wrong with these steps, and would be best to check.
Measurement Phase:
My thought was that I would measure the subwoofer first on its own without involving the mains. My sub has a separate amplifier with line in connectors for signal, and a separate output level control. For REW, I took the Right Output from the sound card's line out and ran it into the sub's line in, and ran the SPL's output into the same right side connector that I used for the sound card calibration.
3) I ran the sound meter calibration procedure as described in the help files. For this, I played the subwoofer test tone, and set the numeric value on REW to match what was shown on my SPL meter. I adjusted the output at the sub's amp so that it read 75 db.
4) Next I did a measurment. This is where I don't understand something.
5) I clicked on the measurement icon, set the start Freq to 15 HZ, and the End Freq. to 200 Hz. When I pressed the "check levels" button, I get a message that says "Level is Low". I'm not sure what level this message is referring to. Is it the output from the Line Out right channel, or is is the output from the sub that is low, or is it something else ?
I was able to set the Level (dB FS) setting to make this message to go away. But when I did this, the measurements were all above the recommended 75 dB level. I don't seem able to find the right combination to make the "Level is Low" message go away while at the same time keeping the measured output at 75 dB. If anyone has any words of wisdom, I'd greatly appreciate it.
Thanks In Advance
Rog
I'm working my way through the steps to use REW, and I've run into something that I don't understand. Here's a summary of where I'm at:
1) I have a Creative Labs "Blaster X-fi" external sound card. This card has separate right and left channels for line out. It has a single connector for line in.
2) I'm using a Radio Shack digital SPL meter.
I believe I have done the sound card calibration properly. I set up the cables as shown in the first attachment.
On this picture, I ran the right line output from the sound card to the right side of the splitter plugged into the sound card's line in. I believe that this Radio Shack Connector splits out left and right signals from the single pin. The picture shows a second splitter which is identical to the one plugged into the sound card for reference.
The second attachment is the sound card's uncorrected response. The corrected response is completely flat from 2 - 24Khz. I don't have a jpeg for this graph.
So am I on track as far as the setup and procedures for calibrating the sound card ?
I think I have done all of the steps correctly, but when I go to the acutal measurment phase of the process, I'm running into something I don't understand, so I thought it's possible that I've done something wrong with these steps, and would be best to check.
Measurement Phase:
My thought was that I would measure the subwoofer first on its own without involving the mains. My sub has a separate amplifier with line in connectors for signal, and a separate output level control. For REW, I took the Right Output from the sound card's line out and ran it into the sub's line in, and ran the SPL's output into the same right side connector that I used for the sound card calibration.
3) I ran the sound meter calibration procedure as described in the help files. For this, I played the subwoofer test tone, and set the numeric value on REW to match what was shown on my SPL meter. I adjusted the output at the sub's amp so that it read 75 db.
4) Next I did a measurment. This is where I don't understand something.
5) I clicked on the measurement icon, set the start Freq to 15 HZ, and the End Freq. to 200 Hz. When I pressed the "check levels" button, I get a message that says "Level is Low". I'm not sure what level this message is referring to. Is it the output from the Line Out right channel, or is is the output from the sub that is low, or is it something else ?
I was able to set the Level (dB FS) setting to make this message to go away. But when I did this, the measurements were all above the recommended 75 dB level. I don't seem able to find the right combination to make the "Level is Low" message go away while at the same time keeping the measured output at 75 dB. If anyone has any words of wisdom, I'd greatly appreciate it.
Thanks In Advance
Rog
Attachments
-
36.4 KB Views: 526
-
79.3 KB Views: 509