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Software based Spectrum Analyzer


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Hello All

 

Does anyone on the forum have experience with software based spectrum analyzers? I realize that SMAART is available, but that is way overkill for me.

I'd like a cheap software analyzer that can be used for live sound to listen to a room and show frequency amplitude on the screen.

 

These are available as standalone units (BSS Varicurve) but I'm thinking there are software based systems for way cheaper.

 

I dedicate a laptop computer to front of house, and would just as soon load up a spectrum analyzer in it to help listen to the room.

Thanks in advance

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do you have an iPhone?

 

 

No. Blackberry guy here.

 

Al.

Thanks for the heads up. I have the measurment mic, but a decent preamp/PCMCIA card is another story. Any suggestions?

 

My studio is full of RME gear and they do make a PCMCIA sound card-preamp combo, but pretty pricey and overkill for what I want to use it for.

Maybe a soundblaster card, but preamp/phantom power is still an issue

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For any iPhone users, I have RTA for the iPhone ($19.99) and while it is of course limited by the mic on the phone, it has already paid for itself when I used it to identify a feedback frequency in a friends bands monitor wedge. I went to the mic with the app launched, cupped the mic, and the offending frequency jumped. Notched it at the board, and feedback gone.

 

Since I still haven't trained my ears to identify frequencies accurately, it was well worth the price of admission for the app.

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No. Blackberry guy here.


Al.

Thanks for the heads up. I have the measurment mic, but a decent preamp/PCMCIA card is another story. Any suggestions?


My studio is full of RME gear and they do make a PCMCIA sound card-preamp combo, but pretty pricey and overkill for what I want to use it for.

Maybe a soundblaster card, but preamp/phantom power is still an issue

 

 

FWIW, If you are using it to pink noise analyze a room then you need a GOOD calibrated mic/mic pre/phantom, but if you just want to use it to visualy monitor the sound during performance (to find that annoying ring or occasional squeek), your laptop's mic input jack should do just fine (just make sure the mic you use is full range enough (anybody's inexpensive battery powered condenser should work great)). Another option for this scenario is to connect your Que output directly to your laptop's line input (that way you can zero in closer to on just which mix is causing the problem). If you do this you might want to put a pad of 10 to 20db in line as I believe laptops have a -10db sensitivity and most pro mixers have a +4db (often capable of > +24 db) output.

 

Just some thoughts.

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The cheap condenser mics made for plugging into laptops are surprisingly flat but - of course - not usable for EQing without calibration. For those that don't know it the PC mic inputs have superimposed power (~ 3V) for these little condenser mics. I use a $5 (from eBay) Sony ECM-DS70P stereo mic made for a minidisc recorder with my laptop and it is powered just fine. My understanding is that most devices with a stereo 1/8" mic (not line) input have this power available as it is a standard.

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FWIW, If you are using it to pink noise analyze a room then you need a GOOD calibrated mic/mic pre/phantom, but if you just want to use it to visualy monitor the sound during performance (to find that annoying ring or occasional squeek), your laptop's mic input jack should do just fine (just make sure the mic you use is full range enough (anybody's inexpensive battery powered condenser should work great)). Another option for this scenario is to connect your Que output directly to your laptop's line input (that way you can zero in closer to on just which mix is causing the problem). If you do this you might want to put a pad of 10 to 20db in line as I believe laptops have a -10db sensitivity and most pro mixers have a +4db (often capable of > +24 db) output.


Just some thoughts.

 

 

JR.

You bring up and interesting scenario. I do "pink" the room, but really only to confirm what my ears are telling me. How ever plugging in a "que" mix to the laptop is interesting. I assume then launch the spectrum analyzer application and watch it work. Can I take that "que" right off the headphone output of the mixer? That has a level control and may help with the output levels. I could then use the PFL to check all output of the board or individual channels as desired.

I suppose I could take it off the matrix output as well? I use an Allen and Heath GL2400 board.

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If I'm correct, the GL2400 has a cue/solo output that should be a summed mono version of your headphone output (I'm not absolutely familiar with the board), but yes the Headphone output should work. Keep in mind that the RTA software will only accept 1 channel at a time so I'm not sure what you'd want to do if listening to the main stereo mix (don't passively sum the L+R, but you could safely do it through a simple custom made cable with a couple of resistors in it).

 

Since I primarily do monitors (and don't have a lot of use for pink noise) that's how I setup my RTA. It makes finding & fixing problems a snap.

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Thank you all for your input.

Very good info as usual. I have a lot of testing to do.

 

JR

You are correct on the que (monitor) output on the GL2400. More than one option to drive the spec analyzer is available.

 

I'll test and see how this comes out.

 

Thanks again

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