Calibrating microphone with air hose hiss.

[halojoy]

So Bottom line is:
You can use a Hair Drier
and some "Spectrum-Anylyse" software
to calibrate your elektret-microphones.

Have I got this right or ....
... am I not in the truth, yet

/halo - wants to be where everyone else seem to be:
- some place better ....

[Circlotron]

No. Hair dryer is no good at all! Use high pressure air 100 psi or more. Maybe you could try letting down your car tyre. Not as high as 100 psi but way better than a hair dryer.

[EC8010]

Fan noise is most definitely not white noise. Acoustical engineers and submarine sonar operators can analyse the spectrum of fan (or propellor) noise and determine the number of blades and rpm. They then quieten it. The acoustical engineers charge a consultancy fee and use baffles/lagging. The submariners blow it up. They do not charge a fee.

Bicycle tyres (not mountain bikes) operate at 100psi, so that might be a good source in lieu of a compressor.

Many thanks for an excellent calibration suggestion.

[saletel]

true bicycle tires (tubulars) go up to 200 psi http://www.athenscyclepath.com/wconntubulartires.html

and road bikes go from 100-140 (clinchers)

-Eric

[EC8010]

Excellent. Loved the link. Tubs are the cycle equivalent of vinyl. I'd love to ride on tubs but balk at the sewing.

[saletel]

i just built up a tubular wheel set.... the thing about the glue is true. its horrible.

i've wanted to go to vinyl but a) cant afford a nice turn table say a 1200. b) wouldnt have any thing but mom and dads old music......

any suggestions? on other decent players? and cheap ways to get albums? (i think my last one was the alf records that burger king gave out)

-eric

[qwad]

ANY OF THEaforementiomed solutions are pretty iffy I REckon, the min distance for measurements should be 1m unless you are doing NF measurements on ports or bass drivers to see how low they go!( but I cAN"T BEleive there were no instructions with your system! otherwise If I wERE you I would not have bought it!!)the best and most reliable way is to get your mike caliberated by a proffessional who knows what he's doing, then they will give you a floppy with the "cal" file of your mike on it which you load into your measuring programme, which by selecting when taking measurements will automatically compensate for the mikes natural response that's what I did when I built my IMP with MLS.... because I WANTed to be able to correlate my measurements to manufacturers published graphs to see how accurate my measurements is to theirs or vice versa, albeit with one hiccup MLS ( maximum length sequence) pulse signals are more accurate at the top end than sine which a lot of them still use so you see tweeter performance as it really is at the top end.... anyway that depends on measuring system and location, how well one can gate the response acquired te remove room reflections or other artefacts that can affect your results,

[EC8010]

Originally posted by saletel
Cheap ways to get albums?

Charity shops. Trouble is, you have to sort through a lot of "Easy Listening No 4003: Bert Kaempfert's Orchestra Plays Variations on Mozart accompanied by Eric Postlethwaite playing the Brighton Cinema Organ in the Style of Liberace." Out of all the dross, there is likely to be 5% that's worth trying. Of this, 50% has been wrecked by crystal cartridges. But it's still worth a go.