# New to REW and looking for some info.



## Guest (Feb 19, 2008)

So last weekend I finally got a RS SPL and attempted to test the response of my subwoofer, however, an error message popped up every time telling me I had to much head room. The volume was not great enough? Then yesterday evening I tried the same setup and found that the volume was too great.

I am using an X-FI Xtreme Music sound card and the line in is the same as the Microphone, I think, but have read in numerous posts that the Microphone jack is not suitable for testing when connecting the SPL out to the sound card.

More or less I have been reading for a couple of days now trying to figure out what I am doing wrong and was interested in knowing if the Sound Card could be the problem.

Also should I be hearing audio from the L/R channels when testing the subwoofer? Or could I only send sound to the subwoofer using the analog input on the back of my AVR?

Thanks to any who reply. I am very new to this so please bare with me.


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## brucek (Apr 11, 2006)

> have read in numerous posts that the Microphone jack is not suitable for testing when connecting the SPL out to the sound card.


Correct, the mic input is not suitable unless it's the type that can be toggled with software between line-in and mic. Generally, you require a simple line-in since the RS meter outputs a line level out. Note that an SPL meters output is dependant on the scale used.



> if the Sound Card could be the problem


No, that soundcard is fine. Be sure you're using stereo plugs, since the jacks are stereo. Be sure to turn off all effects and soundfields, and use two speaker stereo mode for the soundcard only.
If you're able to complete the soundcard calibration routine, you're good.



> Also should I be hearing audio from the L/R channels when testing the subwoofer?


The analog line-out of the soundcard should connect to the AUX or CD in of your receiver. You can use a Y-splitter if you want at that point to enable both left and right mains.

brucek


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## Guest (Feb 19, 2008)

brucek said:


> Correct, the mic input is not suitable unless it's the type that can be toggled with software between line-in and mic. Generally, you require a simple line-in since the RS meter outputs a line level out. Note that an SPL meters output is dependant on the scale used.
> 
> 
> No, that soundcard is fine. Be sure you're using stereo plugs, since the jacks are stereo. Be sure to turn off all effects and soundfields, and use two speaker stereo mode for the soundcard only.
> ...


Alright thank you for the quick reply I will be certain to go through connections and attempt to get a new sweep.


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## Guest (Feb 19, 2008)

Alright I have finally begun testing again and I think I have an issue when using the line in/mic input on my sound card. I can hear it as though the SPL is a microphone I dont think that should be the case any info in regards to my situation would be greatly appreciated.


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## brucek (Apr 11, 2006)

> I can hear it as though the SPL is a microphone


This is a feature called monitoring that has to be disabled before REW can be used. Every soundcard calls it something different, but it results in the situation you describe. Look in the cards application to find out how to turn it off....

brucek


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## Guest (Feb 20, 2008)

brucek said:


> This is a feature called monitoring that has to be disabled before REW can be used. Every soundcard calls it something different, but it results in the situation you describe. Look in the cards application to find out how to turn it off....
> 
> brucek


Is there anything standard when it comes to finding this. I have googled and searched and found practically nothing regarding this and my X-Fi card.


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## Canadian_Dude (Jan 24, 2008)

Are you using Vista or XP?

In Vista it will look like this. Make sure the one I circled is disabled


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## Guest (Feb 20, 2008)

Canadian_Dude said:


> Are you using Vista or XP?
> 
> In Vista it will look like this. Make sure the one I circled is disabled


Im using XP and I see nothing similar to the menu you have shown. This is actually kinda sad, I am fairly tech savy and have built a number of PCs, I am 1 year away from being an Electrical Engineer and yet I can't seem to turn off my Mic on my PC.


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## Canadian_Dude (Jan 24, 2008)

If you open up your volume mixer and go to options I think it is, and then properties, you should see a couple radial buttons with one that says recording and see if you can turn it off there.


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## brucek (Apr 11, 2006)

Also see this thread with regard to CMSS and also the red + symbol above the line-in slider. The Soundblaster external may operate the same as the one in the thread I mention.

Either way, post a pic of your soundcard mixer and also the Windows Playback and Record mixer.

brucek


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## Guest (Feb 20, 2008)

Canadian_Dude said:


> If you open up your volume mixer and go to options I think it is, and then properties, you should see a couple radial buttons with one that says recording and see if you can turn it off there.


Im beginning to wonder if it is the sound card, I have tried muting it and disabling the microphone in the properties and nothing seems to work. It seems as though the Mic/Line In is only both and never just one or the other.


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## Guest (Feb 20, 2008)

brucek said:


> Also see this thread with regard to CMSS and also the red + symbol above the line-in slider. The Soundblaster external may operate the same as the one in the thread I mention.
> 
> Either way, post a pic of your soundcard mixer and also the Windows Playback and Record mixer.
> 
> brucek


Will do. And I did check out that thread and for whatever reason my Mixer is not similar to the one used in that thread.


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## Guest (Feb 20, 2008)

http://i58.photobucket.com/albums/g253/watsonte/REW.jpg

Here are the Mixer play control and mixer properties menus.


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## brucek (Apr 11, 2006)

Yeah, I can't see that picture too clear. 

Can you just post it on the site like the pics below of Playback and Record.

I do think I see the Line-in not muted in Playback. It should be.

See mine below and the Line-in is muted in playback (no monitor mode), but selected in Record.

PLAYBACK








RECORD








brucek


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## Guest (Feb 20, 2008)

brucek said:


> Yeah, I can't see that picture too clear.
> 
> Can you just post it on the site like the pics below of Playback and Record.
> 
> ...


Yeah... sorry about the pic, but, I will do as you suggested.


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## Canadian_Dude (Jan 24, 2008)

I also see that you don't have the Line-in checked in your properties menu.


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## Guest (Feb 20, 2008)

I had gone through a series of menus attempting to turn off the microphone, but was unable to do so. I did try using only the Line-in for Recording and still it did not turn the Microphone function off. 

I had manage to edit enough menus to disable the sound card so after starting up the PC today I had no sound. I will try going through the whole process again later on this afternoon.

Thanks again for all your help.


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## Guest (Feb 20, 2008)

Alright so started over entirely and sure enough your suggestions did work thanks again for the help brucek and canadian dude...

Now I just have to figure out how to calibrate my sound card.

After the first couple of runs I was getting a pretty consistant graph, any thoughts on the graph below would be greatly appreciated, the sub I am using is an Epik Knight, I have the crossover set to 80hz and all of my speakers set to small-80hz, using an HK AVR 445.


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## brucek (Apr 11, 2006)

The first thing you need to do when measuring a sub is set the vertical axis to 45dB-105dB and horizontal axis to 15Hz -200Hz. This is the standard values we use here and allows for easy comparisons for everyone. The Graph Limits are set with the Graph Limits button in the top right corner of REW and you simply recall it anytime the axis changes.

When you measure a sub first, you want to measure it alone without the mains so you can see its singular response. So, disconnect your mains. (be sure the power is off ). Also be sure the receiver is in stereo with all effects off and the crossover set.


brucek


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## Guest (Feb 20, 2008)

brucek said:


> The first thing you need to do when measuring a sub is set the vertical axis to 45dB-105dB and horizontal axis to 15Hz -200Hz. This is the standard values we use here and allows for easy comparisons for everyone. The Graph Limits are set with the Graph Limits button in the top right corner of REW and you simply recall it anytime the axis changes.
> 
> When you measure a sub first, you want to measure it alone without the mains so you can see its singular response. So, disconnect your mains. (be sure the power is off ). Also be sure the receiver is in stereo with all effects off and the crossover set.
> 
> ...


Alright will do, thanks again.


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## Guest (Feb 20, 2008)

When measuring only the Subwoofer how close should the SPL meter be to the subwoofer? Or should the volume of the subwoofer or AVR be adjusted to account for the difference in volume when only measuring the sub?


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## Guest (Feb 21, 2008)

Well, here is the response with MV @ -25db...


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## brucek (Apr 11, 2006)

> When measuring only the Subwoofer how close should the SPL meter be to the subwoofer? Or should the volume of the subwoofer or AVR be adjusted to account for the difference in volume when only measuring the sub?


The mic should be at your normal listening position. REW is set up to 75dB at the listening position. Your target is way off. Set the target level to 75dB.

Also set your graphs to LOG and not LIN.

brucek


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## Guest (Feb 21, 2008)

brucek said:


> The mic should be at your normal listening position. REW is set up to 75dB at the listening position. Your target is way off. Set the target level to 75dB.
> 
> Also set your graphs to LOG and not LIN.
> 
> brucek


When I am attempting to set the target level I should use the AVRs volume to match that target level correct? Also, I seem to have an issue when setting the target volume, but, I am not sure how to correct it as all connections are made and are correct to the best of my knowledge.

Edit: More issues, no feedback from the SPL Meter, it seems as though my SPL meter has stopped working, I get zero input readings when running REW now. Any reason this may have occured?


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## brucek (Apr 11, 2006)

> When I am attempting to set the target level I should use the AVRs volume to match that target level correct?


Yes, just run the Settings Check Level routine and set the level at the listening position to 75dB using the SPL meter. Then set the Input Level correctly and then run the Calibrate SPL routine, which just matches the REW SPL meter reading with the real SPL meter (so they track).

No idea why your meter isn't working. Plug it into the AUX of your reciever and see if it works - it's a microphone - talk into it.

brucek


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## Guest (Feb 21, 2008)

brucek said:


> Yes, just run the Settings Check Level routine and set the level at the listening position to 75dB using the SPL meter. Then set the Input Level correctly and then run the Calibrate SPL routine, which just matches the REW SPL meter reading with the real SPL meter (so they track).
> 
> No idea why your meter isn't working. Plug it into the AUX of your reciever and see if it works - it's a microphone - talk into it.
> 
> brucek


Alright well I cant really thank you enough, like I said originally I am very new to audio calibration so it's nice to have someone who will spend the time to explain almost everything.


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## Guest (Feb 21, 2008)

I think I finally got it right....Let me know what you think.

If I apply 1/3 Octave smoothing it gets rid of my two major dips...What does that really mean in terms of output though? Like I said before Im very new to this stuff.


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## brucek (Apr 11, 2006)

> I think I finally got it right....Let me know what you think.


You set a target of 85dB - normally we use 75dB, but it's OK if you like 85....



> If I apply 1/3 Octave smoothing it gets rid of my two major dips...


Smoothing is used on full range measurements when comb filtering obscures the overall trend and the smoothing helps reveal the response a bit better. Don't use it on a sub measure.

Your subs low end extension is quite good, but terribly wonky between 15-40Hz. Have you tried moving it around to smooth it a bit?

brucek


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## Guest (Feb 21, 2008)

brucek said:


> You set a target of 85dB - normally we use 75dB, but it's OK if you like 85....
> 
> 
> Smoothing is used on full range measurements when comb filtering obscures the overall trend and the smoothing helps reveal the response a bit better. Don't use it on a sub measure.
> ...


I have yet to move it too much, I plan on really moving this thing around sometime this weekend when I have a little more time on my hands. 

My apartment could be contributing somewhat, at least I think it could, to the odd dips, the walls are plaster and the wood floors are paper thin...I also have part of the support for a fire escape right beneath the sub, so currently I am hoping it is only the location thats the issue.


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## Wayne A. Pflughaupt (Apr 13, 2006)

> I have yet to move it too much, I plan on really moving this thing around sometime this weekend when I have a little more time on my hands.


Hopefully that will help. Usually when we see response this ragged, it’s a placement issue.

Regards,
Wayne


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## Guest (Feb 22, 2008)

Wayne A. Pflughaupt said:


> Hopefully that will help. Usually when we see response this ragged, it’s a placement issue.
> 
> Regards,
> Wayne


Well, I moved the sub around for about 2 hours. I was able to flatten out the response between 16-25hz, and then from about 40hz on...Still odd dips occurred at 30 and 35 every time. I wish I had saved some of the sweeps, but after moving and tweaking and moving and tweaking I lost track of what was where.

Also, the location where I seem to get the best response also resulted in moving the most furniture so sadly I will leave it at my original position and allow my larger mains to take some of the heat off around 30hz...

At this point I would be willing to bet my odd dips are more related to the poor construction of my room than poor performance of my sub.


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## Wayne A. Pflughaupt (Apr 13, 2006)

> At this point I would be willing to bet my odd dips are more related to the poor construction of my room than poor performance of my sub.


I don’t think you can characterize any sub that can solidly hit 15 Hz as a “poor performer.” 

Do you have a good corner available? I.e., one with no openings on either wall close to it?

Regards,
Wayne


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## Guest (Feb 22, 2008)

Wayne A. Pflughaupt said:


> I don’t think you can characterize any sub that can solidly hit 15 Hz as a “poor performer.”
> 
> Do you have a good corner available? I.e., one with no openings on either wall close to it?
> 
> ...


No, the only two decent corners available are too close to my sitting position and create a very localized sound. In fact I actually feel more pressure (on my ear) depending on where its placed, left or right.


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