Model Boat Mayhem - Forum

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: JJC sound  (Read 2361 times)

crzydoyle11

  • Guest
JJC sound
« on: March 15, 2010, 11:29:13 PM »

Ok I do know that JJC is longer around but maybe some one here can help I hope.. I am trying to get more volume from the sound unit, I can not hear it to well when Eng go to half speed, Really cannot hear at all when the boat goes full speed.
All that I did is added a round tube to the speaker in the attempt to make louder.. No good with that. can I add anything to it like maybe a bigger volume controll knob? Or anything electric that will mike the sound louder..any help you can give I will be thank full.
Thanks to all Brian
Logged

DickyD

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 9,497
  • www.srcmbc.org.uk
  • Location: Southampton UK
    • SRCMBC
Re: JJC sound
« Reply #1 on: March 16, 2010, 08:02:23 AM »

Silly question I know, but have you turned the volume up ?

What size speaker are you using ?
Logged
Richard Solent Radio Controlled Model Boat Club http://www.srcmbc.org.uk

crzydoyle11

  • Guest
Re: JJC sound
« Reply #2 on: March 16, 2010, 09:22:11 AM »

NO not a silly question.. Just a silly answer  :-)) yes I did turn up the volume.. and I am useing a 2.5 inch speaker. that was size that Harbor models rec. to me at the time. I have not tread a bigger speaker yet, do you think that may help?
Logged

MCAT

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 417
  • Location: FARNBOROUGH HAMPSHIRE
Re: JJC sound
« Reply #3 on: March 16, 2010, 09:31:49 AM »

I have a similar problem, Ive yet to do something about. I'm sure its on this site somewere that you need to make sure that
the speaker is of the bottom of the boat, by an inch or so something to do with the way sound emits from the speaker.
you also need a tube to channel the sound upwards to give it more of a chance to be heard.


This info maybe not inch perfect but Im sure the main points are ok,  hope it helps

Mick
Logged

DickyD

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 9,497
  • www.srcmbc.org.uk
  • Location: Southampton UK
    • SRCMBC
Re: JJC sound
« Reply #4 on: March 16, 2010, 09:48:17 AM »

I have 4" 8 ohm speakers on mine as recommended by JJC.

Might help.

The size of the speaker is under the Accessories and Fitting requirement section





If you cant zoom in enough to be able to read these send me a PM with your e'mail address and I will send full size scans.
Logged
Richard Solent Radio Controlled Model Boat Club http://www.srcmbc.org.uk

FullLeatherJacket

  • Guest
Re: JJC sound
« Reply #5 on: March 16, 2010, 10:16:40 AM »

The amplifier chip in all of the JJC units which I have handled is a Philips 15W job (@18v). It's the same one that we fit to the new P101, and also the same one as was fitted to the RCMW units. At 12v this puts out about 7W which is way too much for most 2 1/2" speakers. Richard is nearer the mark with a 4" x 8 Ohm one, but it should be 10W rated. See John Elsy's posting about the volume he gets with his RTTL with the same amplifier chip and a 4" speaker. One of the main problems with JJC engine sounds was the lack of adequate heat-sinking on the amplifier - not that important for momentary sounds like horns but not good for those which run constantly. Turn up the wick fully and the thing is going to overheat and die at some stage.

If you arrange to enclose the back of the speaker in a box, so that the air pumped out from the back of the cone never interferes with the air coming off the front, then you'll find a significant increase in volume.  Mount the speaker and box firmly on a (baffle) board affixed inside the hull, to increase the resonance from the hull itself. A sound tube can also help by keeping the column of air from dissipating inside the hull, and you must - of course - allow a reasonable opening for the air (sound) to escape. No point in having just a small grating or a half-open vent - that's like turning on the radio, then leaving the room and closing the door behind you.

FLJ
Logged

malcolmfrary

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 5,529
  • Location: Blackpool, Lancs, UK
Re: JJC sound
« Reply #6 on: March 17, 2010, 04:11:03 PM »

Its always a good idea to have a big hole to let the sound out.  Most of us are nervous about the same hole letting water in.  This can be got round by covering the inside side of the hole with a slack piece of cling film.  This keeps water out, but lets sound through. You se the arrangement in banks and at ticket offices (or you did before they went fully armoured and started using an intercom)
Logged
"With the right tool, you can break anything" - Garfield

crzydoyle11

  • Guest
Re: JJC sound
« Reply #7 on: March 18, 2010, 01:05:28 AM »

Ok I have tyred theTube on the speaker but the sound is not loud enough for me still, But I will got a bigger speaker and with the tube install or even the box and than see how that will work. As for my Hull since it is a Ariz tug the hull is big that maybe part the problem as well. But I tread the ides that I see hear and thank you all Brian..
Logged

portside II

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,517
  • tugs at rest
  • Location: Howden.East Riding of Yorkshire.England Near the banks of the river Ouse
    • goole model boat club indi site
Re: JJC sound
« Reply #8 on: March 20, 2010, 10:37:51 PM »

Just as FLJ say's , i have a jjc turbo cat diesel with the recomended speaker in my Brakengarth , and all i did with mine was make a ply box (open top) for the speaker to fit in . It is under the wheel house and i have fitted grills (mesh) where the windows are and the sound booms out no probs.
daz
Logged
I like to build my boats to play with, not to just look pretty,so they dont !

andywright

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 538
  • Location: Barry, South Wales
    • Windpowersails
Re: JJC sound
« Reply #9 on: March 25, 2010, 12:16:25 PM »

I have a sound tube on my speaker, made from a piece of cardboard tubing from a carpet shop, diam is same as speaker outer ring. I have "engine room vents" in the rear of my tugs accomodation housing to let the sound out, by the way its a JJC turbo cat unit.

Andy
Logged
Navigational Aids vessel Master. Old Conway 70-72

tigertiger

  • Global Moderator
  • Full Mayhemer
  • *****
  • Online Online
  • Posts: 6,966
  • Location: Kunming, city of eternal springtime, SW China.
Re: JJC sound
« Reply #10 on: March 25, 2010, 01:15:07 PM »

The design/addition of the speaker box is important. Just putting a tube on the front of the speaker may not help a lot. But with the addition of a closed box behind the speaker, this will throw the energy (sound) forwards up the tube.

The sound box can also add resonance and emphasize the lower frequency (bass) sounds.
Logged
The only stupid question is the one I didn't ask

lifeboatpaul

  • Guest
Re: JJC sound
« Reply #11 on: March 25, 2010, 04:44:30 PM »

I have a few of these sound units and have successfully used car amplifers to increase the sound, basically you take the two speaker wires and connect these to the input wires (one channel only) and the connect the amp`s out put wires for the same Chanel to you speaker, On my arun lifeboat I had a amp with graphic equalizer fitted and changed the tone completely.

FLJ is correct earlier in this thread that the JJC amp unit gets hot and later models had a heat sink fitted , to be sure of protecting my precious units ( non left to buy )
I have fitted small computer fans running off the same 12v supply that feeds the unit on a frame over the unit.

I bought one of these units a few years ago second hand with no connector plug ,which was a pain ,so I located the correct type (Phoenix connections ) and bought some ---they only come in a pack of three -like other things !!!-but seriously if any one is short of one of these I have spares.

Paul.
Logged

portside II

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 1,517
  • tugs at rest
  • Location: Howden.East Riding of Yorkshire.England Near the banks of the river Ouse
    • goole model boat club indi site
Re: JJC sound
« Reply #12 on: March 27, 2010, 04:41:49 PM »

not sure on the validity but a member of the goole club mentioned that metcalf mouldings were doing JJC sound units, if any one can check .
daz
Logged
I like to build my boats to play with, not to just look pretty,so they dont !
Pages: [1]   Go Up