Help needed i'm building a moble boom box 8'hx16'l x8'w pull by a truck going around the village. i've got 2 jbl 15'' 8ohm loudspeakers, 1 jbl sub woofer 8ohm 15'' and 4-6x9 speakers for the front and for rear side of the boom box 2 - 18'' punch sub woofers 4ohms and 4-6x9 speakers'also 2-1000w for front and 1- 1000w for the rear all of will power by 1000 cranking amp battery with a charging system hook on the truck now will the amps carry the load thank you roy

Is the sub dual voice coil?

riverray1969 it would help if I knew the exact model number of that JBL sub you are referring to. With that info I can provide exact specs.


Basically, you need to build/modify an sub enclosure that is suited for the sub, the music you mainly play, and vehicle tuning. Generally, sealed enclosures will provide tighter bass response and get decently loud. Some would argue that it will give you greater sound quality. A ported enclosure will give you a louder more booming sound. That depends also on where the port is tuned (ex. 32 hz, 36 hz, etc ). You need to make sure that the enclosure meets the sub's airspace requirement as well. A customized well made enclosure is just as important as the sub you put in it.

Register and download the manual for free at retrevo.com

http://www.retrevo.com/support/Behringer-EP4000-Amps-manual/id/23591dj795/t/2/

http://www.raltron.com/cust/tools/parallel_resistance.asp

It's ohm's law, dude. 1/a + 1/b = 1/total. One each 8- and 4-ohm speaker in parallel per channel would be 2.7 ohms (nominal). So it will work in theory.

How you manage the potential difference in volume between dissimilar speakers on the same amp channel is a mystery.

Distortion will kill any speaker, not power. Stay within the amp's usable range.

I guess you didn't get the owner's manual, huh?

http://www.jbl.com/HI-IN/Products/Pages/ProductDetails.aspx?PID=SCS200.5BK/230

Where are the amplifiers in this scenario?

Page 8: The sub needs a subwoofer Line Level pre-out from an AV Receiver or multichannel processor. Though not elaborated on in the manual, the L and R Line Level RCA connections are probably for use if you lack a Sub Out feed. Running L and R from your receiver would allow the sub to derive a Sub Channel.

The rest of the speakers would connect to the AVR's speaker outputs.

Pasge 9: Alternate method if your eelctronics lacks a volume-controlled sub pre-out. This method routes only the front speaker level power to the sub so it can extract something resembling an LFE channel, then it routes speaker wire out to the front speakers, not as an audio power source but simply as a pathway.

You still need amplifier channels for all but the sub.

are you connected to the battry haveyou got earth

JBL is obviously just putting their name on your product. Just the way it is. They put their name on it, but use inferior parts. It is cheaper for JBL to have other folks make the stuff.

Try going to Alpine web site, I think they have box building program as well that you just input your sub models into and it gives you blueprints for various types of enclosures. I know Rockford has one and a comparative attachment to compare equipt specs. Or if you call Alpine headquarters you may be able to get info that way, I once sweet talked a rep @ a demo vehicle I met doing some car shows that turned me on to a senior rep @ Korbon Trading the owners of Rockford Fosgate and they gave me specs for a 5 stage band pass box for some competition subs that was more intricate and detailed than anyone before that could find me, Won me first place in spl. Matching your box specs to your subs is crucial and the best specs are often kept a secret for demo competition vehicles! So ask around with some competition guys or other top experts if your real serious about your boooom.

HERE is the owners manual for your sub.

If looking for LOUD, ported enclosure is the way to go.

If looking for accuracy, build sealed.

You dont have enough depth for an isobaric setup.

using the maximum dimensions given, 8x13x41, the volume of the biggest enclosure you could make (assuming 3/4" MDF material) is 1.7cu ft.

To tune this 1.7cuft box around 50Hz, you need (1) 4" round port 5" long.

MTX recommends an enclosure of 2cuFt ea. You will only be able to use 1 subwoofer in this application.

Even a sealed enclosure is recommended 1.25cuFt.

You can shove 2 in the vented enclosure, but you may not be happy with the outcome.

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You can connect them in a series/parallel configuration. Put two of them in series and then connect the last one in parallel across the two in series. This would give you an impeadance of around 2.7 ohms. Only do this if your amp is stable at 3 ohms or less. I am not familiar with the specs of your amp. If your amp is only 4 ohm stable you can not do this.
This would also give you half the power on the two subs in series as the power for the one that is parallel. The two in series would be sharing the total output signal, where-as the one in parallel would get the entire output signal from the amp.
if you were to connect a fourth sub woofer in this configuration it could give you a 4 ohm load, by adding the fourth sub in series with the single sub that is in parallel. or in other words, yu have two sets of 2 sub woofers each in series. That gives you two 8 ohm loads (two 4 ohm subs in series is 8 ohms). Then you take the two sets of subs and parallel them (two 8 ohm loads in parallel equals 4 ohms).

If i had a picture to show you it would make sense, two subs in series that are in parallel with two subs in series.

JBL