The importance of measuring your sub+room response (1 Viewer)

[Kevin C Brown]

BruceD- Be careful of the 1100 to 1124 upgrade. I did that, and while I got absolutely no improvement in any kind of performance metrics, the 1124 "buzzed" more. (The power supply in the case.) Tightening down the screws of the case helped, but some day, I will still sell the 1124 I have, and try a "different" one to see if I can get a lower buzz example.

 

[Richard_M]

Hi Kevin

If you upgrade you should look at going to the DEQ2496, has quiet power supply, mute power on/off, plus a few more nice smarts...

 

[Edward J M]

Craig:

It's best to go directly into the sound card "Line In" with the output from the mic preamp. Then go from the sound card "Line Out" to the subwoofer or pre/pro (if you want to include the mains in the sweep). TrueRTA defaults to the sound card line inputs.

You "might" be able to configure the soundcard to read the USB connection as the Line In, but I never had the need, so I never bothered learning how to accomplish that.

Ed

 

[Craig Chase]

Richard - The M-audio Mobile-pre does have its own sound card, and had a USB interface. According to David Fabrikant (president of Ascend Acoustics) this by passes the internal sound card (I think that is what he said), and uses the much more accurate sound card of the Mobile-pre .... did I hear him correctly ?

 

[Edward J M]

You'll need to find a way to keep TrueRTA in the loop as both the signal generator and the signal analyzer.

You "can" use TrueRTA to just analyze sound generated by other sources, but you lose several important features of the software - namely QuickSweep, Sine, Pink, White, the dBu/MV scale, and the ability to calibrate/correct for sound card FR anomalies.

Regardless, you'll still want to have the new mic/preamp professionally calibrated and input the correction factors into TrueRTA; assuming the mic/preamp combo (even a pro grade unit) has a perfectly flat FR isn't a good idea.

 

[Richard_M]

Craig...



Okay in this case I am assuming that you plug both your mic & line out into the M-Audio.

Therefore for it to work when you installed the drivers they must have become the default drivers for windows, this has allowed TrueRTA to work.

You can check to confirm this under Windows control panel - Sound & Audio Devices.

As Ed has alluded to if the M-Audio is not handling both sides of the equation you will loose a lot of functionality.

 

[Kevin C Brown]

Richard_M- re DEQ2496: A little expensive, but looks interesting. One question, one thing I hate about the BFD is the turn on and turn off thumps. (I actually have a three step turn on process to eliminate this.) Does the DEQ2496 have this?

 

[Ned]

Can I use the rat shack meter with TrueRTA? Is there a mic calibration file for it?

 

[Richard_M]

Kevin...



Yes it does come with a calibration file for the Radio Shack meter, best way is to download the program Level 1 is free, and have a play.

 

[Edward J M]

Last time I checked, there was no cal file for the RS meter (maybe he's added it recently?). I suppose you could use the standard RS correction factors...

John Murphy does make mention of the RS meter, though. I think he stated its line output could be high enough to overload the soundcard if the mixer input levels aren't dropped way down. Not sure how "clean" (from a THD standpoint) the output is from the RS meter, either.

 

[Ned]

There are only these calibration files with the demo:

Gold Line MK8A Mic Cal.txt
Mic Cal typ Behr ECM8000.txt
Mic Cal typical panasonic.txt

Found it.

http://www.etfacoustic.com/Software/RSAnalogueSPL.zip

 

[Richard_M]

Thanks for the update info ED.

I am glad you found the file Ned, I also use ETF5, this must be where I had got the file from.

Sorry Ned for putting you wrong in the first place.

 

[Ronneil Camara]

Hi Brian,

Is this a reliable way of getting the SPL? Assuming I stood at position Y where I got the most SPL: will it be the same SPL if I put the sub there(position Y) on my sitting position?

Thanks.