# Is the RS meter "good enough"?



## 3ll3d00d (Jun 6, 2006)

I'm getting back into REW after quite some time not fiddling with my system. The no of mics available seems to have exploded somewhat in the intervening time so I'm left wondering whether the RS meter can still be considered "good enough" for home use? i.e. subwoofer eq (currently BFD but likely moving to an inuke based system soon) & time alignment of mains/sub. 

Alternatively what is the current recommended minimum/simple setup for this use (with subs that extend <15Hz)? I have no use for a mic apart from this & prices for mic/preamp in the UK seem to be rather more expensive than US prices.

I suspect this Q has been asked before but I can't find a clear answer in the many other threads around the subject.

Cheers
Matt


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## AudiocRaver (Jun 6, 2012)

The RS meters are pretty good for work between 100 hz and 3 Khz. There is a generic calibration file (LF correction only) on our downloads page that makes their accuracy better at lower frequencies, but the correction amount is around 40 db at 10 hz so real accuracy there would be suspect without individual calibration.

If you have have HDMI output from your computer for REW use, a USB mic (miniDSP UMIK-1 or Dayton UMM-6) is an easy way to get up and running. For calibrated accuracy below 20 hz, you will need one from Cross-Spectrum Labs, they calibrate down to 5 hz. If you are using analog out from your computer, you will need an analog mic (Cross-Spectrum Labs) and a calibratable sound card (see our database) for good LF accuracy.

Edit: If you just want to see that your LF response is "fairly smooth" down there, and are not really concerned about absolute accuracy, the RS meter with our generic calibration file will give you a good general picture.


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## tonyvdb (Sep 5, 2007)

If all your using the Radio Shack meter for is to take readings of the sub yes its good enough, if you want to get full range readings then you will need to move up to at least the Galaxy CM140 or even better a calibrated ECM8000


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## Macattack (Mar 20, 2013)

tonyvdb said:


> If all your using the Radio Shack meter for is to take readings of the sub yes its good enough, if you want to get full range readings then you will need to move up to at least the Galaxy CM140 or even better a calibrated ECM8000


I would like to build on the the OP's question. I am in the middle of learning the REW tool, have an RS SPL meter \ Behringer UCA222 \ Laptop setup and am 'making measurements' moving speakers around. I do want to get full range measures to support more ROOM tuning and am looking for how best to do that.

-- The mics you list above seem to use XLR connections but the UCA 222 uses RCA. Can I use an adapter to go 'down' to an RCA for my UCA222 DAC?

Or more directly, what MIC options would work best with the UCA222? I also will use this mic only for this purpose - measuring and optimizing my theater and 2 channel rooms.

TIA


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## tonyvdb (Sep 5, 2007)

The issue is that you need a calibration file for the mic your using. The ECM 6000 and 8000 are the only stand alone mic's that have these available (you can make files for other mic's but you need the detailed specifications for the mic). The Galaxy CM140 is a SPL meter thats better than the RS meter but its still only good up to 12k at best.


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## Macattack (Mar 20, 2013)

tonyvdb said:


> The issue is that you need a calibration file for the mic your using. The ECM 6000 and 8000 are the only stand alone mic's that have these available (you can make files for other mic's but you need the detailed specifications for the mic). The Galaxy CM140 is a SPL meter thats better than the RS meter but its still only good up to 12k at best.


Thank you. Sounds like with an ECM8000 (~$60) and an XLR to RCA adapter, I am good to go! That is clear.


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## tonyvdb (Sep 5, 2007)

You will need a phantom power supply to use the 8000 as well.


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## Macattack (Mar 20, 2013)

Macattack said:


> Thank you. Sounds like with an ECM8000 (~$60) and an XLR to RCA adapter, I am good to go! That is clear.


Placing my order on Amazon ---- Quick question. Which XLR to RCA adapter do I need from the ECM8000 XLR output to my UCA222 RCA input? 

FEMALE to RCA or MALE to RCA?


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## tonyvdb (Sep 5, 2007)

You first need to have a phantom power supply for the mic. You cant just "convert" the XLR to rca without a proper transformer. You are essentially going form Balanced to unbalanced.


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## AudiocRaver (Jun 6, 2012)

Hold that order...

The UCA222 is not a mic preamp. You need a mic preamp. A preamp will accept the XLR and will supply phantom power. And lots of gain. The UCA222 will not work with a mic input directly.


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## tonyvdb (Sep 5, 2007)

You should get one of these


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## AudiocRaver (Jun 6, 2012)

That would work.

The Q502 includes phantom power and a USB interface, eliminates the need for the UCA222, gives a much cleaner setup.

The ART USB dual pre is another good, simple option.


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## Macattack (Mar 20, 2013)

Okay, thanks! Yet another toy I have to purchase .


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## 3ll3d00d (Jun 6, 2006)

OK thanks. I suppose the q is when is an rs meter is not accurate enough for sub eq? Possibly this is a how long is a piece of string question. Do they drift at all?

Are there any issues with running a USB mic over a long (10m) cable? I have a feeling USB is limited to <5m or so.

Cheers
Matt


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## AudiocRaver (Jun 6, 2012)

3ll3d00d said:


> OK thanks. I suppose the q is when is an rs meter is not accurate enough for sub eq? Possibly this is a how long is a piece of string question. Do they drift at all?
> 
> Are there any issues with running a USB mic over a long (10m) cable? I have a feeling USB is limited to <5m or so.
> 
> ...


Here is one way of looking at it. Many home theater enthusiasts are looking for smooth subwoofer response, but not necessarily flat subwoofer response. Many home theater setups end up with subwoofer frequencies emphasized some amount above the rest of the frequency response curve as a matter of personal taste. The import thing is that it is done in a smooth, controlled fashion.

The RadioShack SPL meter with our generic calibration curve will do a good job of helping you achieve smooth response, which is definitely the main priority for good-sounding bass. Then you can adjust the amount of bass somewhat for personal taste by playing with the target curve in REW during the EQ process. If flat response is also a priority for some reason, or if there is a specific known target curve you want to achieve closely, then you need an individually calibrated measurement mic or SPL meter for that.

USB cable lengtht: 5 m is about the limit. Some devices, USB mics included, can work reliably with a buffered USB cable for extra length beyond that.


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## 3ll3d00d (Jun 6, 2006)

AudiocRaver said:


> Here is one way of looking at it. Many home theater enthusiasts are looking for smooth subwoofer response, but not necessarily flat subwoofer response. Many home theater setups end up with subwoofer frequencies emphasized some amount above the rest of the frequency response curve as a matter of personal taste. The import thing is that it is done in a smooth, controlled fashion.
> 
> The RadioShack SPL meter with our generic calibration curve will do a good job of helping you achieve smooth response, which is definitely the main priority for good-sounding bass. Then you can adjust the amount of bass somewhat for personal taste by playing with the target curve in REW during the EQ process. If flat response is also a priority for some reason, or if there is a specific known target curve you want to achieve closely, then you need an individually calibrated measurement mic or SPL meter for that.


that makes sense. Part of the reason I'm thinking about this is because I've recently seen what looks like audyssey producing a flat response that my spl meter measures as flat but +5-6dB higher (i.e. it looks a bit like a step down at 80Hz). I know there are various issues in measuring what audyssey has done with REW but it still looks quite odd.


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