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Discussion Starter · #1 ·
Hi Everybody,

I am new here so I would like to say 'hallo' to everyone.

I have a question regarding other than Galaxy SPL meters and the misterous (for me ;)) calibration file.

I am not able to get Galaxy MC-140 here in Poland (amazon won't ship here) however there are a lot of other SPL meters on the local market.

Can I use them with REW? How to create calibration file then? Should I apply for one to the producer?

For example:
CEM DT-8851 (please paste the name to google as I am not allowed to paste links :()

or

CEM DT-8850

Thank you in advance for your help.

Best regards,
Kensei
 

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Can I use them with REW? How to create calibration file then?
No problem using any SPL meter with REW. You can create a calibration file from a calibration graph or from calibration data if available.

If all else fails, you can click the C-Weight box in REW (and use C-Weight selection on the SPL meter) and then don't expect the results to be too accurate at the low end of the frequency spectrum. Below 20Hz most meters don't track their C-Weight curve very well and this is where a cal file is useful.

You can get your SPL meter calibrated and use that file with REW, then you'll know it's accurate.

brucek
 

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Welcome to HTS Kensei :wave:

The SPL meter can be attached to the REW thou some of use the Behringer ECM8000 calibration microphone along with preamp providing phantom power 48v to the ECM8000.

I need to buy a new Behringer MIC100 as my preamp gave up the ghost this week strange?:gah: I had no choice to use my analogue SPL db metre attached to the computer to run REW.
 

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Discussion Starter · #4 ·
Thank you for your answer...
You can create a calibration file from a calibration graph or from calibration data if available.
If I got it correctly... to create calibration file I would have to have calibration graph or calibration data (e.g. how mic in the SPL reflects reference frequencies) delivered by manufacturer or professional laboratory, wright?

I suppose I am not able to measure the SPL response to reference signal, to have the calibration data by my own?

As far as I understand, if I am not able to get it (no tables or graph delivered) it is better to rely on the C-weighted correction than to apply correction file from other meter (for example Galaxy)?

Best regards,
Kensei
 

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Isn’t there a data sheet showing the differences in frequency response for the microphone and SPL db metre on this site, I’m fairly sure I recall reading the data a few months ago?
 

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If I got it correctly... to create calibration file I would have to have calibration graph or calibration data
Yes.

I suppose I am not able to measure the SPL response to reference signal, to have the calibration data by my own?
Very difficult to carry out.

if I am not able to get it (no tables or graph delivered) it is better to rely on the C-weighted correction than to apply correction file from other meter (for example Galaxy)?
Yes, it would be much better to rely on the C-Weight curve than use a generic file for a different meter.

brucek
 

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Discussion Starter · #7 ·
Thank you very much for all answers :)

One more question.

While choosing SPL meter should I take one with automatic ranging or manual (for example low: 35-100 dB, high: 65-130 dB)? There is signifficant difference in price :(

Best regards,
Kensei

BTW. Andysu I haven't found any data sheet on the producer's website :(
 

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Can I use them with REW? How to create calibration file then? Should I apply for one to the producer?

For example:
CEM DT-8851 (please paste the name to google as I am not allowed to paste links :()

or

CEM DT-8850
Doing a quick google, those meters will cost you more than a calibrated mic from Cross Spectrum (USD $65-$90 with the HTS discount + shipping). Herb has a sign-up for the next group buy.

http://www.cross-spectrum.com/measurement/calibrated_dayton.html

Edit: here's what you get in the way of calibration. The Behringer mic is similar to the Dayton mic in the group buy. Mention your HTS ID to get another $5 off in the group buy.

http://cross-spectrum.com/measurement/calibrated_behringer.html

No relationship with Cross Spectrum, just a satisfied customer.
 

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Discussion Starter · #10 ·
Denis,

Thank you for your suggestion, however please remember that I live in a strange country like Poland :) I would have to add to the price of Behringer or Dayton mic from Cross-Spectrum VAT (22%) + duty (ca. 4%) + shipment costs to Poland (min. 40 usd) + SPL meter cost anyway (as far as I know I have to have it to set up dB level) + preamp for the mic (optionally with the soundcard as I am using Macbook Pro without line-in/line out).

I guess for my purposes (optimisation of the listening room) using Behringer UCA 202 USB + SPL Meter (as a measuring mic as well) should be fine from the cost point of view (e.g. ca. 160-230 usd). Or am I wrong?

Best regards,
Kensei
 

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I guess for my purposes (optimisation of the listening room) using Behringer UCA 202 USB + SPL Meter (as a measuring mic as well) should be fine from the cost point of view (e.g. ca. 160-230 usd). Or am I wrong?
Correct. Note that Radio Shack meters are considered only accurate up to 3KHz. That should be fine for sub EQ and room treatments though.

brucek
 

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Thank you all for your answers.

One more "stupid" question. My meter got AC and DC output. Which one should I plug into my soundcard?

Kensei
 
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