12 Volt system help needed (first build)

satta sound wrote: ... transported by a bike. I will mainly play roots reggae and dub(reggae) on it, .....

A man after my own heart :-)

Right - well I'd say you have a good start. If its a "CCTV" Li-ON battery, it won't have the advertised capacity, but will last remarkably well driving a Lepai 2020 - I have direct experience of that.




This thing might be butt-ugly - but it kicks up a whole load better than it looks.
2 x old JBL car speakers - not like the new crappy ones - big heavy magnet.

Next stage up in my case is to double up the amp+battery and add a bit of weight to the sound, as in :-



bottom section is 2 x 4R 8" woofers in reflex cab ....

This little lot is a right old bodge really, but does the job really quite nicely. I don't have a crossover, when in dual-box mode I just turn down the bass on the top box and up a bit on the bottom one :-)

In fact the bottom section drains battery quicker, so I tend to use a 7Ah SLA for that if more than 3-4 hours is reqd.

The very cheap and nasty "karaoke mixer" works OK for a bit of mic action :-) .... s/n ratio is atrocious, but I don't care - doesn't spoil the music. Runs the whole day on a low-capacity 12V CCTV battery.

i would like it to run say a day or evening. For a little bbq party somewhere in the outsides or just for a day chilling at a beach or something..
So.. portable as transport it by bike.. or more bikes.. but maybe with some customizing to the bike:P
Allready got a rack mounted on the handlebars.. i hope you get the idea?

Slaz thanks for the idea!
Like the oldschool look, but i think that's not what i want.
I want to build my own cabs and optimise them.
I want to know if it's possible to run this of a single LP2020a+
2 10 inch 8 ohms
2 8 inch 8 ohms
and some piezos.. 4 ?

Thanks slaz

i've been a student electronics so i do have some experience with it. i want to have it switchable between using the crossover or not, thuss using the 10"s or not.



so it's sure that the 10's have to be in an extra cab.. or is it better to put them in 2 individual cabs and the rest in one?
How do i design the cabs for this all? or could someone here help me out with that?

Thanks!

Thanks Saturnus!

I was allready aware of your boominator! Great project!
It has been a great source of information for me.
Only thing is that i rather would have the sound only going one side.
Is there a way to adjust the boominator like that?
Thanks!

satta sound wrote: Thanks slaz so it's sure that the 10's have to be in an extra cab.. or is it better to put them in 2 individual cabs and the rest in one? How do i design the cabs for this all? or could someone here help me out with that?

To be honest - the overall size/weight of enclosures youd need to mount all 4 drivers (esp. if using reflex) is gonna be a bit too much to move around by bicycle without a trailer.
Certainly you could make the 2 x 8" + piezos box bicycle-movable .....

It will also depend on the drivers - do you have T/S params for the drivers ? If so, use WinISD to get an idea of the size of enclosures that would be needed.

Myself - I'm looking into alternatives to plywood/mdf for the enclosures ....
Of course neo magnets would be nice too ..... but the kind of drivers equipped with neo magnets tend to be high-powered full-on PA ones - which can get quite expensive - as you're paying for that kind of design/charateristics.

Not much use building a great-sounding system, then finding its too heavy/awkward to move it to where you wanna use it !!





Edited by slaz - 08 February 2012 at 10:36am

Saturnus wrote: satta sound wrote: Thanks Saturnus! I was allready aware of your boominator! Great project! It has been a great source of information for me. Only thing is that i rather would have the sound only going one side. Is there a way to adjust the boominator like that? Thanks!   I'm not quite sure what you mean. Sound does spread in all directions no matter how you mount the speakers. The Boominator just uses that fact for an advantage instead of a drawback. The most annoying thing about a boombox that isn't bipolar is that the sound coming to the back side is very distorted and frequency limited. I truly believe a bipolar speaker is less annoying to be on the "wrong" side of compared to a monopolar speaker.

It might be an advantage in some situations .... definitely not for me. If you want it in the middle of a field at a festival or some such - yes you might want that. I want the sound field to primarily be in front of the speaker box - in the direction the drivers face .... "spillage" in the other direction can be a problem.