Can't get REW set up... strange stuff

[Darren]

Hi,

I've been trying to get REW set up to measure my subwoofer response so I can generate some filters for my BFD but I'm having problems. I'm using my built in sound which has DD 5.1 and I'm using the digital coxial out and the mic in.

1. When I connect the Radio Shack analog meter to the mic input the meter then reads totally differently than when it isn't plugged in. Basically it always has a reading, even when there is no audio or test tones. Should I have it unhooked when I set the measurement level so I can actually get a reading?

2. I can't get my sound card to calibrate. It gives back a graph that looks like a feedback loop but I can't find any option to fix that.

Help

[brucek]

When I connect the Radio Shack analog meter to the mic inpu

You must use the LINE-IN input and not the MIC input. The RS Meter outputs line level.

brucek

[Darren]

brucek wrote:

You must use the LINE-IN input and not the MIC input. The RS Meter outputs line level.

brucek

Interesting, I couldn't get a reading with the line-level input....I'll try again. I couldn't calibrate until I used the mic. I'm using a mono mini-jack, do I need a stereo one?

I think I just figured it out, It appears it does indeed need to be stereo, I was able to get a reading momentarily by jiggling the mono plug so I assume it's contacts need to be stereo.

EDIT:
Well, I got it to calibrate the soundcard once but wanted to go through the whole process again and after that it won't calibrate again.

From the instructions:

Connect the soundcard's line output directly to its line input - use the channels that will be used to make system measurements

So, does that mean I should use the digital coaxial out to the line-in? I can't get a reading doing that but if I go from the line out to the line in I do get a reading but it only worked once.

[brucek]

So, does that mean I should use the digital coaxial out to the line-in?

Nope, you don't use digital. You can't create a soundcard cal file with it.

You use analog line-out to analog line-in.

As you've discovered, you must use stereo 1/8" plugs, but only use one channel. A stereo (1/8" to two RCA) adapter works best. Then you just hook up one RCA cable.

Sometimes the soundcard cal is funny. If it gets in a funk, clear the soundcard cal data with the REW pulldown (Soundcard pulldown and select Clear Calibration Data) and then restart the program and try and create the file again.

brucek

[Snookboy]

Bruce,

I could use some clarification on this. What cable needs to be stereo? From the SPL meter to the sound card line in or when you connect the line in to the line out for sound card measurement? Or both? Or from the line out to the processor and/or BFD? The reference to channel also has me puzzled. There is only one line in on my sound card. Channels are not an option, nor are they on the meter of course. On the line out I have three choices: one for front L/R, one for rear L/R, and one for center/sub. I am using the front L/R using a cable with an 1/8" on one end and two RCA plugs on the other. The two RCA plugs I am connecting to a L/R input on my processor.

So I have an RCA from the SPL to an RCA/1/8" adapter to the line in on the sound card. I have the front L/R of the sound card (single 1/8 connection) to the L/R input on the processor.

This seems correct to me, however, if I have all sources but line in muted on the sound card, I have no sound. I have to unmute the WAVE source.

Thanks Bruce.

[brucek]

Snookboy

Here's the diagram (from the REW help file) for the hookup to your soundcard and receiver and BFD.

Notice the adapters in and out of the soundcard are both 1/8 stereo. but you only use a single channel (either left or right) in and out of the soundcard. Be sure to select the same channel in REW (left or right) that you have the cable hooked to. Normally everyone uses right. You also use the same right channel for the soundcard calibration routine (that you only do once and then save the file).

I know there is only one line in and one line out on your soundcard - but they're both stereo with two channels (Left and Right).

Yes unmute the wave.



If you don't like those heavy 1/8" stereo to RCA adapters you can get a cable type like this:
It's still a stereo 1/8" to two RCA connectors.



Still confused?

brucek

[Snookboy]

Bruce,

I appreciate your patience. If that picture is from the REW help file, I must have an old version, because I have been pouring over that thing and have not seen that illustration. It explains it perfectly. Thanks a million.

[brucek]

Yeah, it's the help file in the sticky REW Links and FAQ section at the top of the BFD forum:

http://www.hometheatershack.com/room...tml/index.html

brucek

[Snookboy]

Ok, I was using the help from the program...did not see this. Thanks.