Sound Card Calibration Problem

[allredp]

I've set up my BFD and downloaded REW and the Java so it can display.

I've chosen the audio input and output ("default device"--as explained in the help files).

I'm using my HTPC--Win XP Media Center with a 7.1 Realtek AC97 soundcard.

I've routed the input to the output (made the loop) and I've gone to settings where I've selected the "measure" button.

The setings window comes up and shows the mostly dead settings page--the only moving parts are the VU meters (input and output) of which the input numbers are changing between -47.x on the top and -48.x on the bottom. There is no visible activity in the meter itself. It sits like this for some time.

Also, unlike the Help file says, no "instructions" pop up for me to follow.

If I minimize and go back to the REW main page I can't see anything happening there either except at the bottom left where numbers like 17.x--19.x/35 DMB are ascending up and then dropping back down. The next number is 48000Hz followed by 16Bit.

There is a graph under Filter Adjust, but it just sharply drops out of sight from after 2.0 and 4.0.

Help!

Thanks,
Phil

[allredp]

I'm going to post the graph that my soundcard calibration efforts produced.
-- Phil

[brucek]

I've gone to settings where I've selected the "measure" button.

The setings window comes up and shows the mostly dead settings page--the only moving parts are the VU meters (input and output) of which the input numbers are changing between -47.x on the top and -48.x on the bottom. There is no visible activity in the meter itself. It sits like this for some time

You're supposed to press NEXT at the bottom right hand corner of the settings screen to carry on from that point.

brucek

[allredp]

Hey Bruce!

You're probably thinking I'm a total idiot (which is really true most of the time ), but my HTPC displays the computer screen too big for the limits of my TV size! Since it is a TV working under Media Center, it has this problem...

This isn't the first time I've not seen something the computer is displaying due to the discrepancy with the monitor size.

I'll see if I can't get my mouse to scroll down there in the bottom right and hit that "next" button!

Much appreciated!!!

--Phil

[allredp]

ok, after the "next" fisasco, I've successfully made a soundcard calibration file! Does this look correct? I'll be moving on to the other instructions in moments--just thought I'd see what this looks like to you guys...

Thanks for bailing out a newbie!

-- Phil

[allredp]

So, here's my calibration check graph--this looks right, correct?

Baby steps for most are giant leaps for this low-techie!

But, I am enjoing the ride very much in spite of my tech deficiencies...

Thanks a ton for the help!
-- Phil

[brucek]

You're probably thinking I'm a total idiot

No, it was your excellent explaination of the problem that made the answer easy.

this looks right, correct?

Yep, all looks good.

Why are your graphs so narrow?
Graphs should be log and not linear scaling. (Press Freq Axis icon at top right of REW main page.
Set graph limits for all sub measurement to vertical of 45dB to 105dB and horizontal 15Hz to 200Hz..
To save proper sized jpgs of graphs press the save icon at the lower left corner of the plot to save as a standard 800 width jpg.

brucek

[allredp]

Thanks so much for the great help, Bruce.

I'll fix the graph parameters and get some testing done tonight.

Also, I'll switch my soundcard to "stereo."

However, this should be changed back after calibration, right? If my HTPC is going to produce surround sound for the AVR, it will need to be selected as 7.1, right? I'm using the digital coax cable from my HTPC to connect to my AVR.

I'm way excited to get the filters loaded into my BFD! Getting closer...

-- Phil

[brucek]

If my HTPC is going to produce surround sound for the AVR, it will need to be selected as 7.1, right?

Yep.....

I'm using the digital coax cable from my HTPC to connect to my AVR

But not for REW of course. For that you're using analog cable from the soundcard line-out?

brucek

[allredp]

Hey Bruce,

Yes, I do have the analog line-in/line-outs to the AVR (and sub out to the BFD) and RS SPL respectively.

Thanks for making sure--you can never be too sure with newbies like me!

I only mentioned that my normal HTPC output to the AVR is through the digital coaxial out.

After some painting in my living room I'll be back at getting the REW set up!

-- Phil

[allredp]

ok, so here I am ready to measure--I run the measure, which sends out a pink noise to make sure my levels are ok (it reads 13 or 14), then I measure which causes a sweep. Both of these are audible and seem to be what you'd expect.

However, all that is generated in the main window is an .mdat file with the REW assigned file name of the date/time of the sweep I look at the graph and there's obviously something wrong--but I saved the graphs anyway so you can see (hopefully) what I'm doing wrong.

BTW, I'm pouring over the REW Help files!

Also, I can't seem to get the graphs to look like everyone elses! I'm using the default settings, but they just turn out like this!





Any ideas of what I'm doing wrong?

Up to date, I've calibrated the soundcard successfully (as per the graphs above), I've set the input level to be 75db and also calibrated the spl level to match the 75db.

I've put my RS Meter (with corrected calibration file loaded) on a tripod at ear level at my listening position.

Hummnn...

Thanks for any help!

-- Phil

[allredp]

It's late enough out East so I expect I won't get help till tomorrow, so I thought I'd work over my own troubleshooting.

I did find that I had incorrectly loaded my soundcard cal file in the meter/mic spl spot--so I fixed that and ran "measure" again.

My levels are reading -13.5 db and OK, then I hit the "start measuring" button where the sweep sounds off (only once) and says that I have 10.6 db headroom.

Problem is here's the graphs it produces.

This is the latest one:

This is all the measurements together:

This is a "waterfall" just to help diagnose my problem!


As per above, I'm not sure what I'm doing wrong with the graphs--I'm using the default REW settings (and checking them against the Help file instructions), but these narrow, truncated graphs are all I seem to be able to produce...

I hate being low-tech, with high-tech tastes!

So, I'm sure I've just missed something horribly obvious and you'll set me right so I can get this addiction actually producing something!

Thanks for the enabling,
Phil

[brucek]

The horizontal scale should be 15Hz to 200Hz.
The vertical scale should be 45dB to 105dB.
Enter these into the Graph Axis Limits pop-up that starts when you click the Graph Limits ICON at the top tight hand side of the main REW screen.
It will remember these limits and you can click it anytime to return your display to those scales.



To save the graph in a jpg, simply click the icon located at the bottom left of the graph and create a jpg at 800 width.

I have no idea how you are getting those one inch high graphs?

It's impossible to interpret them until you supply a normal sized plot....

brucek

[allredp]

Yeah, it's a mystery to me too!

I have those parameters in the graph properties--I have checked and re-checked them.

I'm wondering if somehow my HTPC running through a low-def 36" Sony Wega TV, which doesn't have the native resolution to display the whole computer screen is causing this problem? Recall that I couldn't see the "next" button in the soundcard calibration settings window. It happens again when I work on the input levels window. I actually have to toggle with the TAB key to get to buttons in REW and hit ENTER instead of using the mouse.

Is is possible that REW is only working off the screen size I have? I.E., because I have to use the window in a semi-minimized format, is that shrinking the graphs? I can't figure out any other explanation for it!

BTW, how do you do screenshots? Maybe it would help if I could .jpg my REW main screen to show what I'm seeing...

Let me know what you think!

Thanks big time,
Phil

[brucek]

BTW, how do you do screenshots? Maybe it would help if I could .jpg my REW main screen to show what I'm seeing

Press the Print Screen button on your keyboard (Prt Scr upper right hand corner of keyboard).
Paste into any graphic program (Paint etc) and resize to 800 wide..

Why not use a computer monitor when using REW?

brucek

[allredp]

I'll trade in a computer monitor tonight...

Hopefully I can't mess that up!

I'll also do a print screen and paste it in tonight as well--thanks for the instructions.

Thanks,
Phil

[allredp]

So, I haven't fixed the monitor issue yet, but will do so soon.

In the meantime, look at these screenshots please and help me see what I'm doing wrong!

BTW, the "dummy" measurement below was actually done without the SPL even hooked up! I just did it for kicks to see what it would do--it acted pretty much the same as when I had it on its tripod the other night. The results are pretty much the same in terns of what I'm seeing with the graphs, and there are no filters suggested.

Seems like even though I'm getting the sounds of the measure test and the sweep through my system (both my mains and the sub), it isn't registering through my RS SPL back to REW (obviously also tonight when I didn't even have it hooked up)...










There's got to be something very simple I'm missing!

Thanks for any help!
-- Phil

[brucek]

In the meantime, look at these screenshots please and help me see what I'm doing wrong!

Those aren't the shots needed to establish what's wrong. We would need the palyback and record MIXER pictures....

brucek

[allredp]

Sorry about the wrong screenshots! (but at least I can create them now--thanks to you)...

Please help me know where I go to find the "playback" and "MIXER" screens.

You should get an award for patience Bruce!

-- Phil

[brucek]

Double click the little speaker in the system tray to reveal the playback mixer. It looks like this:



Click options / properties and select Record and it looks like this:



brucek

[allredp]

OK, here are the screenshots you asked for!






I'm anxious to know what simple little thing I messed up that has cost me hours!

Thanks much,
Phil

[brucek]

Select Line-In in the Record mixer and select it.
In the Playback Mute the CD and Synth.

Actually, why don't you just select the Line-in and Speaker out instead of the Default device in REW and then you can use REW to adjust the levels and take control of the mixers, like the following.



brucek

[allredp]

OK, I've taken a screen shot of what you told me to do...

Right after I post this I am going try to measure again!



Does this look right--and are the values correct?

Thanks a ton,
Phil

[brucek]

Does this look right--and are the values correct?

yep, Looks correct. The values of Input Volume will be set by you when you run the Check Levels routine.

brucek

[allredp]

Well, now I can't get any sound out of either set levels or spl settings or measure!
I'm including screenshots that may be helpful in troubleshooting...
I'm a pain--I'm actually painful to myself...









Currently no sound when trying to check levels or spl or measure...

Don't quit me Bruce! I'm committed to getting this working!

Thanks,
Phil