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My weekend Noise Canceling Speaker Hack


My weekend hack:
I have been living with a MFJ 281 ClearTone(yea right) speaker on my 857D since day one. With the bands so bad and the noise floor so high it drives me crazy to have to have the volume so high just to try to hear a faint QSO. The constant hiss was maddening.

I started looking into Noise Canceling Speakers but the high price and me just starting back to work after 7 months of unemployment, I could not bear to spend the money on one.

The 857D has some "good" DNR functions, but they just dont cut it with the dinky Cleartone and my ears.
I have several Onkyo speakers from a Surround Sound system and a 100 watt 12 volt car audio amplifier and started to think on hacking this into something usable.

I picked up a Behringer MINIFBQ800 9 band Graphic Equalizer from Amazon for $70 and after a few hours ended up with this.  It actually works quite well and the difference is amazing between this and the Cleartone.

I could have saved some money and got a cheaper by buying a cheaper model knowing what bands need to be suppressed, but this one had the best S/N ratio of 95 dB vs some that were in the 60dB range.

The quality of the audio coming out of the radio does not warrant this level of EQ, but more is better right? I order this before getting the O Scope program or I would have know that 90% of all the noise is coming in at 2kHz..

Now just looking for the bands to clear and see how this thing works when it opens up.

Here is the link to the Blog post with links to the components for this project.

I have a MFJ 281 as well, never used with my ft-857 as the internal speaker seems way better to me as far as pulling things out of the noise.
not that the internal speaker is that good either

I like your solution quite a bit,
nothing like an external EQ to fix audio
it runs on 9VAC...
I am guessing it runs internally on a split power supply, my guess is + 9 to +12V and -9 to -12V
did you set up some conversion to 12VDC ?

I like your solution too. I didn't know anyone still sold separate equalizers for cars, or anything for that matter. I thought that went out with the mullet haircut.  :o

Your hack makes perfect sense since ham radio audio filters or processors (or whatever slick term they want to stick on it) are themselves just glorified equalizers.

Built in speakers are almost universally crap, so any improvement is significant. When I really need to hear something, I use headphones.

Nice project. Well done.

Thanks guys.  I Will do a write on on the parts and wiring tomorrow and a video with sound showing the difference. 


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