# So I got everything I need finally ... now i'm stuck with calibrating.... need help



## SQBubble (Nov 12, 2007)

So I have the ECM8000 and FINALLY got the US-144, after a month and half waiting... Now I can't calibrate the mic with REW, I don't have a SPL reading on the ecm8000 nor the tascam us-144... ? any inputs? also, How can i calibrate my soundcard adjusting the volume with the master volume of the computer... It just ignores my master volume, I can only adjust the volume with REW and Nullsoft winamp, for some weird reason..?


thank you in advance


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## brucek (Apr 11, 2006)

> Now I can't calibrate the mic with REW, I don't have a SPL reading


Well, your options are to get an SPL meter or simply guess at the 75dB level. When you're doing the Check Level routine, you are to set a 75dB level at your listening postion by adjusting the volume control of your receiver. Make a guess as long as it's reasonable. Then set your input level of REW (that's coming from the ECM8000) and finish the Check Levels. Now simply go to the Calibrate SPL routine of REW and set it to 75dB. It's fine.



> How can i calibrate my soundcard adjusting the volume with the master volume of the computer... It just ignores my master volume, I can only adjust the volume with REW


The soundcard has taken the Windows control away. Simply adjust the levels with the Tascam dials. Set the REW sweep level to -12dB and adjust the output level of the Tascam along with the reciever to 75dB at the listening position (which you'll guess at). Then use the Line-Input dial on the Tascam to adjust the input level..

Be sure the monitor mode mix is turned off in the Tascam.

brucek


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## SQBubble (Nov 12, 2007)

ok thx for the reply.. but I think im really off the road here, I dont think my computer is detecting the mic... the tascam is though, the mic is connected to the mic in "right" , phantom is on, Mon Mix is at "computer" , Mono is on. I installed the tascam drivers... im on vista 32-bit.


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## SQBubble (Nov 12, 2007)

After messing around with it, I now realized that the whole system must be connected to the Tascam instead of my computer's soundcard and set the Tascam "as default soundcard" in the control panel.

After doing this, I went in REW and tried to calibrate the soundcard , but I dont know what to put on the "input device", nothing is working, I only got line in, microphone, default device, primary capture sound(for the Tascam), none of them work...? With my computer soundcard, I got "What you hear" option and that worked very well.


Its like something is missing with the Tascam...

Well, after couple of hours messing with this, I'm getting very confused and all messed up with inputs, outputs, mic in, line in!!! I tried so many connection to make it work...

Now it's time to go sleep and relax a bit! hehe

Please help me out, I really want this to work it's been 2months!!

thanks


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## brucek (Apr 11, 2006)

> With my computer soundcard, I got "What you hear" option


That option is a monitor mode. It gives the illusion of working but does not, since it's only a loopback internal to the card.



> Please help me out, I really want this to work


OK, let's start. The first thing that needs to be done is a soundcard calibration. If this can't be carried out, there's no use in advancing further. It will tell you if the card is going to work.

The only connection to your PC will be the Tascams USB cable. Remove all the other cables from the Tascam.

I would like to see a jpg of both the Playback and the Recording Devices screens. To access these, right click on the speaker icon in your system Tray on the desktop and select one at a time and post. 
Also post a jpg of each of those two screens Levels tab.

Also post a jpg of the REW Settings screen.

That will save me from asking a million questions.

note on jpg: to save an active screen on the desktop to the clipboard, press Alt-PrtScr keys and then save to a graphics program to make the jpg

brucek


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## SQBubble (Nov 12, 2007)

ok, here they are.





























ok now its better, click on the yellow thing to make it bigger!! do I have to connect the ecm8000 to the Left *and* Right input in the tascam?


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## brucek (Apr 11, 2006)

It's all correct except, on the REW Settings page, change to 48KHz Sample Rate and also unmute the Output Volume Check box.

Then leave the Tascam is stereo mode.

Then connect a cable from the Right Line-out to the Right Line-in. The cable will be an RCA to 1/4" TS phone. No other cable will do, except (You may substitute a regular RCA to RCA cable and use a RCA to 1/4" TS phone adapter.)

Run the Soundcard calibration routine with the REW sweep level ~-6dBto-9dB and use the Tascams line-in dial to set the input level.

Let me know how that part went...

brucek


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## SQBubble (Nov 12, 2007)

Ok, I did this, RCA line out left to 1/4jack line in Left, phantom power turned off, and in stereo mode and it works, this is what I'm getting:


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## SQBubble (Nov 12, 2007)

now how do I calibrate the microphone ? I ran the test but it doesnt detect anything from the mic


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## brucek (Apr 11, 2006)

> Ok, I did this, RCA line out left to 1/4jack line in Left, phantom power turned off, and in stereo mode.


No, you have right selected as the channel you're going to calibrate, so you don't loop the left channel. you loop the right channel.

So anyway, do it again with the loopback cable connected to the *right channel* and then when you get the soundcard cal routine finished, save the file so it's loaded into REW.

Then, to test that the file is correct, go through the Check Levels routine, and then do a Calibrate SPL routine and set it to 75dB.

Then do a Measure routine. 

The result should be a flat line. This means all is well and we can continue to actually measuring something.

So, see how that goes and post the flat line for me.... after that you remove the loopback cable.

brucek


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## SQBubble (Nov 12, 2007)

ok this is what Im getting in the right channel soundcard FR











is it normal im getting this time of impulse? because with the x-fi its totally different...


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## SQBubble (Nov 12, 2007)

and this is what I get with a different setting, I suppose it is better...


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## brucek (Apr 11, 2006)

> and this is what I get with a different setting, I suppose it is better...


Yep, that's fine. 

You should save the soundcard cal file and have it loaded into REW. A good check to see if all is well, is to take a measurement of the loopback cable in place and the result should, of course, be a flat line, which says the calibration file is working as planned. Once that's established, remove the loopback and you're ready to measure.

See this thread on connections and proceed to taking measurements. Be sure to load the meter or mic calibration file into REW from our download section.

brucek


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## SQBubble (Nov 12, 2007)

alright, everything is good now, its working! thanks a lot for the help.

just a last quick question, is it possible to measure the system with the x-fi soundcard instead of the one in the tascam?


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## JohnM (Apr 11, 2006)

The last impulse response is noisier than it should really be in the pre-impulse region, that is typically a sign of sample rate conversion being carried out somewhere - if you have REW set for 48k try setting it to 44.1k (or vice versa) and take a measurement to see if it looks cleaner.

Using an X-Fi would be fine with an SPL meter, but you need a preamp with phantom power for the ECM8000.


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