Sound System Vibration

[Dave_5113461]

Hi

A bit of advice needed as regarding securing the fastenings used in caravan construction.

I've just installed a CD /MP3 car radio type player in my Bailey Bordeaux and have found that the fittings such as the lockers and seats start becoming loose after listening to the sound system.

Very strange, but I have installed the system with the help of my friends and they reckon that it is a normal car sound system. I have the 48" sub woofer cabinet under the back of the U- shaped lounge and the 800watt amplifier fed off its own 110 amp battery which used to power the motor mover. I didn't need that so I took it off and sold it on e-bay.

The problem arises when I'm sitting outside the caravan and have to turn the volume up to be able to hear / feel the bass.

Eventually the vibration gets too much with the fixtures working themselves loose and with the distorted sound caused by loose fixtures fellow caravanners start to complain.

I had a slightly bigger system in my old 7.00 mtr Hobby and no one ever complained about the distortion then so it must be the inferior build quality in British caravans.

What's the difference between the 2 makes??

Thanks

Dave

 

[vauxhall2]

lack of head phones

 

[clivea]

Hi,

but did anyone complain about the noise on site, or is this a windup?

It is all to do with natural resonances that are excited by the sound vibrational frequency and amplitude. A good book to help analyse the problem would be 'vibration Theory and Applications- An extensive treatment of the vibration field from single degree of freedom systems to stochastic time varying problems' by William T Thomson. Alternatively do waht aero and auto engineers do which is to add damping mass (heavy bitumen) sheets onto the vibrating panels. roofing felt layerd up works well and it will also help keep the damp at bay!

 

[parker1158]

Have you tried turning it up louder or getting a bigger amp and more speakers. It may be like a wheel balance problem on a car, they wobble at around sixty but you can often drive through the wobble and the car can be smooth again at seventy.

Alternatively you could try pumping expanding foam into all the lockers and cupboards. This will 'firm up' the van without compromising on your MTPLM.

I remember having a similar problem when I installed a forty two inch plasma tele and cinema sound system, DVD and video plus freeview box and satalite, some of the unnecessary items like fridge, cooker, shower/toilet compartment had to go.

Sadly sometimes you have to make sacrifices to accommodate the necessities

 

[Dave_5113461]

Have you tried turning it up louder or getting a bigger amp and more speakers. It may be like a wheel balance problem on a car, they wobble at around sixty but you can often drive through the wobble and the car can be smooth again at seventy.

Alternatively you could try pumping expanding foam into all the lockers and cupboards. This will 'firm up' the van without compromising on your MTPLM.

I remember having a similar problem when I installed a forty two inch plasma tele and cinema sound system, DVD and video plus freeview box and satalite, some of the unnecessary items like fridge, cooker, shower/toilet compartment had to go.

Sadly sometimes you have to make sacrifices to accommodate the necessities

You're right mate!

When you mentioned the removing of uneccessary items, it reminded me of that Feng Shui/ Beer advert, where the designer removes everything except the chair beer fridge, TV and bog.

I'll try that - although filling the fridge with more beer may help, which will also lead to a full Thetford might help to dampen the vibrations.

If that doesn't work heavier speakers.

Cheers

Dave ;-)

 

[Dave_5113461]

You're right mate!

When you mentioned the removing of uneccessary items, it reminded me of that Feng Shui/ Beer advert, where the designer removes everything except the chair beer fridge, TV and bog.

I'll try that - although filling the fridge with more beer may help, which will also lead to a full Thetford might help to dampen the vibrations.

If that doesn't work heavier speakers.

Cheers

Dave ;-)

 

[Fouldsy]

Dave

I think the main problem is that you are listening to Massive Attack, you know damn well the low verb base line will shake the knacks out of anything fixed down.

Try as Fouldsy does, listen to the Dixie Chicks.

Ye Ha!

 

[Dave_5113461]

Hi Fouldsy

Dixie Chicks - nice band!!(Emily - nice Texan girl) Their music probably is probably better suited to playing on my Hilux'ICE.Tem darn girls don't like Bush much do they?

I prefer the Dutch products - excellent dance mixes for the 'van.

Dave

 

[Fouldsy]

Hi Fouldsy

Dixie Chicks - nice band!!(Emily - nice Texan girl) Their music probably is probably better suited to playing on my Hilux'ICE.Tem darn girls don't like Bush much do they?

I prefer the Dutch products - excellent dance mixes for the 'van.

Dave

There,s your trouble, dang my britches, talking bush I had some websites for you to view but the Long Suffering says I will get banned from the forum.

Listen to some Trisha Yearwood instead, now shes thigh slapping!!!!

 

[ProfJohnL]

I think the problem may be with lack of bracing inside the caravan.

A couple of chromed scaffold poles strategically placed from floor to ceiling, Forget the acoustic damping panels, use large red velvet cushions liberally spread around. Reposition the speakers into the exterior walls so the whole caravan becomes the speaker enclosure, That will help with the sound field outside the van, and inside whilst the signal will be out of phase, it will be very intense. Fit a larger fridge (commercial cooler cabinets are best). This will increase the reaction mass, and provide a means of cooling the contained air mass which with such a powerful system will begin to heat up.

 

[Dave_5113461]

Sorry I haven't responded sooner - I've been giging!!

I've had a b*stard of a job getting a pitch this w/e with a decent power supply. Got moved off one site because the dodgy electrics kept blowing on the site everytime I switched on the amp and fridge.

Anyway got a site with a stable 16 amp supply late Saturday and the fridge didn't have to work too hard chilling my brews- cold outside!!

Busy site though, so after the club house had kicked out I decided that it was time for dance mix to chill out to before bed.

Someone suggested that perhaps I might be better charging people like they do i an open air concert. I was a bit shocked as it was my private sounds and hadn't realised that other people were listening!

Very quickly I has quite an audience so I turned it up a few clicks on the remote and the freaking power went out again.

Next moring (Sunday), the wardens helpfully suggested another site 5 miles down the M6 that 'would defintely' have reliable power and no cows.

Apparently last night the cows on the site had tried to get out of their shed for some reason and kicked their cow shed door down which had by sheer bad luck cut through a power cable and shorted out the supply. As a consolation for the power outage the farmer was kindly offering BBQ burgers in the morning to my fellow 'vanners, bit cold but it was the thought that counted.

I'll post soon on Sundays events which were amazing!!

Dave

 

[Longsufferingwifeoffouldsy]

Dave

Still waiting to hear about Sundays events!

Fouldsy is interested in fitting a similar sound system in our van, especially as the Dixie Chicks have now released a new album.

 

[Dave_5113461]

After the shame of BBQ ville, I've been banned from posting anymore(by my wife).

Mind you Dixie Chicks DVD R18 on a 42" Plasma strapped to the side of the Bailey...might even get the bullocks interested again!!!

If I was to get into artificial insemination, might want to change the video...........

See ya

DAve

 

[Rich]

After the shame of BBQ ville, I've been banned from posting anymore(by my wife).

Mind you Dixie Chicks DVD R18 on a 42" Plasma strapped to the side of the Bailey...might even get the bullocks interested again!!!

If I was to get into artificial insemination, might want to change the video...........

See ya

DAve

Sorry to see you have been banned by your wife as I was looking at almost exactly the same problem. I have asked Ciba Geigy to make new sides and floor from fully autoclaved pre-preg carbon honeycomb which is 32mm thick. This is 300% stiffer than the exising sufraces but weighs about 30% of standard even with the Acustafil filling in the honeycomb. The roof had to be re skinned with Titanium honeycomb for flexability and curvature of the roof line. Pitty really if a few of us had it done it would have made it cheaper!! I had been quoted for a one off at

 

[Rich]

Soory I posted this in reply first.........

Sorry to see you have been banned by your wife as I was looking at almost exactly the same problem. I have asked Ciba Geigy to make new sides and floor from fully autoclaved pre-preg carbon honeycomb which is 32mm thick. This is 300% stiffer than the exising sufraces but weighs about 30% of standard even with the Acustafil filling in the honeycomb. The roof had to be re skinned with Titanium honeycomb for flexability and curvature of the roof line. Pitty really if a few of us had it done it would have made it cheaper!! I had been quoted for a one off at

 

[Colin_5040109]

The vibrations from the speakers is not the problem, it is kids kicking footballs against the van side that is losening the internal fittings!