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Discussion Starter #1
I dont have a Soundblaster MP3+ but have a RS SPL digital meter with RCA out and a mic from Denon used for auto room correction, so I was thinking of using the mic as input to the laptop internal soundcard via the mic input and soundcard output via the laptop headset/line out going to the AVR AUX RCA input L and R using stereo plug to split RCA L and R. I intend to try the REW using this set up and see the results. I will use the RS SPL meter to calibrate externally the input SPL level coming from the mic to calibrate the REW SPL meter. Can I use the RS SPL meter RCA out as input to the laptop internal soundcard via the mic input jack? I have tried using the Rives test cd to check the set up but not on continuous sweep on the selected frequency band. I would appreciate your comments and suggestions on this set up. I am still looking for a external soundcard maybe Soundblaster MP3+ as recommended.Thanks!
 

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I intend to try the REW using this set up and see the results.
The results will not be good, I'm afraid.

A couple of problems.

The microphones that are an integral part of a consumer auto eq system will have their calibration files integrated with the receivers firmware to render the mic basically flat over the measurement bandwidth. You don't have privy to this cal file and so using that mic with REW is not a good idea.

The mic inputs to laptops aren't for line type microphones such as SPL meters. They are for the cheap computer type mics that require usually 5 volts to operate. The mic-in port will have a very narrow bandwidth with high gain and high noise floor. You cannot use it for REW. You need a proper line-in from an external soundcard or a line-in on a laptop (not too common).

brucek
 

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Discussion Starter #3
Thanks bruce...so I can use my RS SPL meter both for level calibration and line out going to the external souncard which I still need to have in order to run the REW.Another concern, I read in the forum that the RS SPL meter is only good up to 3khz?If this is so, how can we measure the room response at frequencies higher than 3khz?Are we going to use another mic with line out in lieu of the RS SPL meter like the recommended CM140?If I can have the CM140, I might as well use this all through out the measurement from low to high freq and just use the RS SPL meter to initially set the 75db level?right?Your additional comments will be highly appreciated..thanks again
 

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so I can use my RS SPL meter both for level calibration and line out going to the external soundcard
Yes.

I read in the forum that the RS SPL meter is only good up to 3khz?If this is so, how can we measure the room response at frequencies higher than 3khz?
Use a decent SPL meter or microphone with preamp.

in lieu of the RS SPL meter like the recommended CM140?If I can have the CM140, I might as well use this all through out the measurement from low to high freq and just use the RS SPL meter to initially set the 75db level?right?
If a microphone is used, an SPL meter is required at the start of calibration to set a known level at the listening position. It can be any SPL meter.

brucek
 

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Discussion Starter #5
What descent SPL meter and mic with preamp can you recommend?Where can I buy this equipments and at what cost?Does the CM140 still needs a preamp?does it have a line out RCA jack?Can the CM140 handle the entire freq band?Can I purchase the above items thru credit card and ship it here in the Philippines?
 
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