My new custom built 10' subwoofer

Lira

Lira

Member
mkubawat said:
how to test a speaker with pink noise & where i find it
Click to expand...

Its simple, first you need a reliable pink noise sourcehttp://www.burninwave.com/, such a software with a good sound card( like maudio or similar, cheap audio card wont work) or an audio processor like behringer utracurve pro (DEQ2496) (This one is what i use), a good condenser mic, plugged in the sound card and a software for spectrum analize like TrueRTA http://www.trueaudio.com/rta_abt1.htm, to power the speaker, you need a amplifier with a maximum 0,002THD 100W RMS.

You have to equalize the pink noise output to be as flat as possible in all range of frequencies with the mic that you are using. than you can test the speaker.

Later i put the pink noise with 70% of the power of the amplifier to soften the speaker (I know, it will be a bit loud) and leave for 48hours, than i make all the tests again.


That's it. if you have any further questions I'm here to help

Best Regards
 
Lira

Lira

Member
Well, it's good you record the pink noise on any device such as a good mp3 recorder on 320kbps, and use this as a external pink noise source, them plug the mp3 player on the line in of the soundcard and see if the pink noise of your source is accurate. Be sure to disable any equalizer or sound enhancement devices on the mp3 player to have the pink noise flat. Once you have your source of pink noise ready to go, plug off the soundcard and plug in on an amplifier. Now you put the mic on the mic input of the soundcard, (You can use a mixer between the soundcard and the mic but you will have to plug the mixer on the line in of the soundcard), and start testing. the mic must be at least 20cm of the speaker. If you want you can use a sealed box to make this test, than you can see the curve of frequency of your speaker on the trueRTA. Its a bit tricky to get it working for the first time and get the right parameters, you have to watch for the volume to not saturate the sound of the speaker, testing different volumes, you will get the idea how your speaker can operate in differents powers.

That's it. if you have any further questions I'm here to help

Best Regards
 
Lira

Lira

Member
You mean put the woofer reverse on the box like this?

Or this?
 
M

mkubawat

New member
like a first picture
also post about phase system when play many speakers , woofer (when all speaker are at a place)
 
Lira

Lira

Member
Well, its good only for bass/ sub frequencies, because of the dome of the speaker produces high frequencies will be inside de box. You will have to plug it inverted on the amplificator to be in phase of the other speakers. For bass/midbass its not recomended because you will loose the higher frequencies.
 
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Lira

Lira

Member
This kind of alignment effectively cuts the vas in half, twice the power, and half the box size.
Pros: Very small enclosures, increased power handling, driver non-linearities canceled out (lower distortion).
Cons: Very low efficiency, due to the small size of the recommended enclosures.
 
Lira

Lira

Member
I use with success polyurethane automotive painting, using 4 or 5 layers of panting. If you need a more resistent painting you can do 10 layers for professional use.

Best Regards

Lira
 
M

mkubawat

New member
Lira said:
I use with success polyurethane automotive painting, using 4 or 5 layers of panting. If you need a more resistent painting you can do 10 layers for professional use.

Best Regards

Lira
Click to expand...

I have no spray system, can i use roller for polyurethane automotive painting.if yes which type of roller is suitable for polyurethane.

Thanks for your cooperation.
 
Lira

Lira

Member
Sorry for the late answer;
I dont recomend use roller, but you can try the ones that is not made of sinthetic materials, or try to use a big brush. Try 5 layers of painting, because with brush, you will use more ink.


Best Regards

Lira
 
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