Model Boat Mayhem

Technical, Techniques, Hints, and Tips => The "Black Arts!" ( Electrics & Electronics ) => Topic started by: SunnyBob on April 16, 2012, 01:30:39 PM

Title: engine noise
Post by: SunnyBob on April 16, 2012, 01:30:39 PM
I have a technobots engine noise maker in my boat, it works well, but the noise on the little mylar speaker is unrealistic as it is so tinny.
Any body know how to give it a deeper note?
Title: Re: engine noise
Post by: john s 2 on April 16, 2012, 01:55:53 PM
Possibly a better speaker, and the use of a tube round the speaker. Its unlikly that the wattage is much so you may wish to consider an amp. John. 
Title: Re: engine noise
Post by: Bill D203 on April 16, 2012, 02:00:56 PM
I have a technobots engine noise maker in my boat, it works well, but the noise on the little mylar speaker is unrealistic as it is so tinny.
Any body know how to give it a deeper note?

Mine work great. however you do need to put the speaker in a box. There is books and books all about speaker cabs, but i made mine from some odd bits of timber with a plywood sound board to mount the speaker on.
Title: Re: engine noise
Post by: DickyD on April 16, 2012, 07:02:18 PM
Stuck 4" of Pringles crisp tubular pack to rear of speaker, works a treat.  (http://i124.photobucket.com/albums/p8/DickyD_photos/Smileys/tumb.gif)
Title: Re: engine noise
Post by: john s 2 on April 16, 2012, 07:08:26 PM
Good idea Dickie plus you can eat the Pringles. John.
Title: Re: engine noise
Post by: SunnyBob on April 16, 2012, 09:40:45 PM
hhhmmmm. dont need an amp, i'm surprised how loud it is. The pringles box sounds easy. At the moment the speaker is stuck to a nylon base board (ex chopping board) which has all my electrics on it.
Title: Re: engine noise
Post by: malcolmfrary on April 17, 2012, 10:23:21 AM
The sound coming off the back needs a much longer path than the sound coming off the front of the speaker.  That way, the two don't cancel out.  The 4" of tube is good, I have been known to use a styrofoam cup to form a "cabinet".  If the speaker is mounted in a hole in the board, and the board goes out far enough, that is OK.  If the board acts to form a more or less separate chamber, that will do the job as well.
Title: Re: engine noise
Post by: Bill D203 on April 17, 2012, 01:57:58 PM
hhhmmmm. dont need an amp, i'm surprised how loud it is. The pringles box sounds easy. At the moment the speaker is stuck to a nylon base board (ex chopping board) which has all my electrics on it.

Post a photo so we can all have a look see then.
Title: Re: engine noise
Post by: malcolmfrary on April 17, 2012, 03:02:20 PM
Rule of thumb - the measurement from the edge of the cone to the edge of the baffle should be at least the diameter of the cone.  If it is a box or tube, then its across the front face and down the side until you run out of something to measure.  Or a fully enclosed back. 
The bigger the longest dimension of a closed box, the lower the natural resonance, and generally, the deepest note it will hit.  After that, volume is dependent on how far the cone can be moved, which depends on the construction of the speaker and how much power the amp shoves into it.
Title: Re: engine noise
Post by: portside II on April 18, 2012, 09:22:34 PM
I have one of the techno bot's sound units in my springer , like you i found the sound from the speaker quiet , that was until i put it in a ply box and fitted it to the deck
Now the sound resonates through the entire hull of the springer and with the top on is even deeper , but if you remove the speaker box with speaker from the hull its realy tinny and quiet .
daz
Title: Re: engine noise
Post by: SunnyBob on April 18, 2012, 09:28:18 PM
I have one of the techno bot's sound units in my springer , like you i found the sound from the speaker quiet , that was until i put it in a ply box and fitted it to the deck
Now the sound resonates through the entire hull of the springer and with the top on is even deeper , but if you remove the speaker box with speaker from the hull its realy tinny and quiet .
daz

Strangely, I find it annoyingly loud, but maybe its the tinniness thats annoying me. I'll try moving the speaker to touch the top decking.
Title: Re: engine noise
Post by: portside II on April 22, 2012, 05:13:43 PM
that's the best way Bob , i fing using the hull as a resonator to give the sound some depth.
daz
Title: Re: engine noise
Post by: SunnyBob on April 23, 2012, 06:25:53 PM
I've done so much testing lately that the noise drove me crazy. So I've fitted an off switch in the speaker line, now it will only be heard when I need to impress folk (lol)
Title: Re: engine noise
Post by: Bill D203 on May 04, 2012, 04:28:01 PM
Putting a switch in the speaker line could cause the inbuilt amp to get upset. The better place to fit a switch would be in the 12v supply side