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Design of white noise generator for bathroom??

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My wife doesn't like to hear bathroom sounds, and has asked me to mask them.  We have an ERV (energy recovery ventilation) system in our house, thus putting in a traditional bathroom fan isn't an option.  I've tried manufactured noise generators, but they can't be turned on with just an external switch.  Here's what I'm looking for:

1.  Can be permanently installed in the wall or in the ceiling.
2.  Generates white noise at sufficient volume to mask normal bathroom sounds.
3.  Comes on automatically when it receives power.  (None of the off-the-shelf noise generators come on automatically when they get power - you still have to hit a button on the units for them to come on.  I don't have enough knowledge of electronics to modify one of the commercial units so that it will come on automatically.)
4.  Ideally 120V, but 12V, 24V or other voltage is acceptable; I'll just add a step-down transformer if needed.  I plan to provide power using an everyday 120V motion-activated switch.
5.  I don't care about appearance or size - I'll build a box around it or put the unit in a box in the ceiling.

If someone knows of an existing unit that will work, excellent!  If someone wants to invent one, I think they would sell.  If someone knows of a simple design that I can build myself, that'll also work. :)

Above all, my wife thanks you greatly.  I'm hard-of-hearing, so bathroom sounds don't bother me!

I'm not afraid to respond.  Harrumph.

You would probably be better off with pink noise than white noise. When measured in "real world" terms that are more realistic for the way we create and respond to sound, on a log scale, white noise gets louder as the frequency goes up.  Wimpy midrange, and no lows.

Pink noise, on the other hand, is nicely balance compared to most sounds.  It's how we tune sound systems in a room sometimes; more musically representative. 

The main point is that for audio masking to work, the frequency spectrum and the amplitudes of the source and the masking have to be at least in the same ballpark.

Now... I don't even want to speculate about the particular sounds you'd like to mask, but to do it well enough to actually work, you should probably start with spectral analysis of, eh, uh... the actual sounds.  Uhm.

Then you need to generate something like that spectrum at that amplitude.

The simple approach is just to shotgun it - a pink noise generator, an appropriate amp and speaker, a little experimenting, and hope for the best. 

It occurs to me that the levels will be lower and more representative at the, eh, uhm, listening end, after the source has been filtered and attenuated to some degree, rather than in the little room.  If that's an option at all.  In other words, less total volume from the masking device.


A quick/ugly hack could be to use an MP3 player board. Admittedly over-the-top in terms of the underlying tech!, but cheap(ish) and easy to try different sounds etc. Or maybe just a bathroom/shower radio, tuned on AM to no station.

When I built my house, I had the bathroom walls filled with fiberglass insulation.
The builder thought I was nuts until I told him why.  No more bathroom sounds.

It would mean tearing into the walls though...

Or.  Just turn on the exhaust fan.

Maybe reading this book would help the wife


Then again, maybe OP really gives the thunderbox its name.

In either case it would be remiss of me not to say that you definitely want brown noise to mask it :D

We have a Dohm Classic (for assisting with sleep, not household peace at pooping time), these units are good for masking sounds, and they have a real fan in them not some awful speaker making a jarringly useless attempt at producing broad spectrum masking.



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