Help Wanted Please

[The enchanted broomstick]

I have a Pro-Plus Iampor amplifier running a Pioneer dual voice coil subwoofer. Now i only aquired this sub last night second hand off a mate at no cost. Only 1 voice coil was wired up so naturally with the power my amp has i wanted to add the second voice coil to create some ultimate bass!! I wired it up and KABOOOOOOM its kicking its ass off so damn hard and loud its lovely. But!! the amp keeps cutting out and going onto protected mode.

Obviously i have fully checked for any cross wires which would cause the amp to cut out but im wondering if its the way the second voice coil has been wired at all.

I have the amp bridged on the rear channel (600w rms) going into the back of the sub box the two voice coils are wired up positive to positive and negative to negative, im wondering do i need to wire them up positive to negative and so on? I believe its running on 2 ohms stable at the moment but somehow i think it may well need to be dropped down to 1ohm stable and i just dont know how to do it.

If anybody has dealt with these dual voice coils then maybe they can shed some light for me, it works fine on a single coil and cuts out on 2 voice coils.

Any help would be greatly appreciated, stu (Y)

[nmt_oli]

Hmmm, right- do you know the specs of the sub and the amp properly (just im struggling a bit to believe 600W rms from just bridged rear channels on an amp, when ive got a HUGE single channel amp which can't out put that at 4 ohms (2 ohms yes, it can)).

you need to know what your amp is stable down to, most are not 1 ohm stable. you also need to know the impedance of each vioce coil (likely to be 2 or 4 ohm) then just work out how to wire it up, you may need to wire it in series insead of parralel or vice versa.

[The enchanted broomstick]

this is my amp Iampor

"The iAMPOR is a full range Class-X 4-channel digital amplifier, with an output of 300 watts RMS per channel in 2-ohm" so if it can do 300w RMS per channel at 2ohms then bridging the rear channel surely means its 600w RMS at 2ohms ?

I dont know the specifications of the sub i only just got it and seeing as im at work i shouldnt really be playing around with my car (Y)

any help to you?

Edited November 24, 2005 by The enchanted broomstick

[The enchanted broomstick]

aha just found some piccy's

Above is currently how my sub is wired.

^^ Im thinking it may need to be done like this one ^^

[haydon_peter]

What ohm is the sub?!?!

I would guess its going to be 4ohm, its very unlikely the sub will be 1ohm! You really need to find ut what spec the sub is otherwise you could do some damage...

if you read the spec it show that you can only run the amp at 2 or 4 ohm anyway...

[The enchanted broomstick]

all done i wired it up like the second diagram shown and now everything is fine, i got a temperature tester on the magnet and at 2ohms it was getting extremely hot very quickly making the amp cut out to stop things getting damaged. Now its running at 4ohms the bass is kicking and the temperature is staying relatively cool.

cheers anyway though guys, stu :P

For anybodies future reference subwoofer wiring this page helped me it may well be of use to others at some point, valuable information.

[nmt_oli]

ticcy is indeed correct, hence why i was trying to get you to find out spec.

your amp is 600 RMS TOTAL output at 2 ohms, only 300W RMS from the bridged rear channels at 2 ohms, but that should easily be enough.

so your amp is not 1 ohm stable, and it was going into protection with a certian wiring configuration, my guess is that you wired the voice coils up in parrallel and they are 2 ohms each, so you effectively got a 1 ohm load (your top picure). Your amp can't take that, so it kept shutting down to stop it killing itself.

you either want to wire it up in 4 ohm like your other picture, although you will then only have 150W rms goign to the sub, which is enough to get bass but it won't really kick, or you bridge your front channels as well, and have the bridged front out put to one voice coil, and the bridged rears to the other voice coil. as long as you use splitters to split the signal properly, this should work amazingly, as you will then have the full 600w rms to the sub (although it prob can't take it) so make sure you set it so you don't start distorting the sub, or going beyond its limits or you will shake it apart. this set up will be nice on the amp and the sub, as nothign will be over worked (apart from the sub if you turn it up passed it max, but like i said, it will then sound crap and fall apart.)

however, you will then need another amp if you are already running speakers off those 2 front channels.

Up to you!

Edit- glad to hear you have it working in 4 ohm configuration - nice and safe.

Edited November 24, 2005 by nmt_oli

[The enchanted broomstick]

"your amp is 600 RMS TOTAL out put at 2 ohms, only 300W RMS from the brigded rear channels at 2 ohms, but that should easily be enough."

quote from website "with an output of 300 watts RMS per channel in 2-ohm" so if each channel (all 4) is running at 2 ohms then that comes to a grand total of 1200w RMS power which can be achieved in single bridge mode for just 1 sub if you have one powerful enough to handle that.

I've just checked the user guide and running at 2ohms with the entire amp bridged you can get a total RMS power output of 1200w

It is kind of hard for some people to believe but it is true hence why i bought the amp loads of features, digital clarity and a reasonable price. I would recommend it to anybody. You even have the option to run 6 speakers from the single amp so you could have 2 subs and 2 front speakers plus 2 rear speakers which is where the '3d theatre mode' can come into play nicely.

stu :P

[nmt_oli]

# iAMPOR pure magic - 4-channel full range digital amplifier

# 2 ohm power output: 600 watts RMS, 150 watts RMS per channel

# 4 ohm power output: 300 watts RMS, 75 watts RMS per channel

Im much more inclinded to belive those specs, probably copied off the box/spec sheet rather than the 'description' that is most likely going to be written by the shop.

75w rms per channel is a reasnoble claim, and fairly average for high end amps at 4 ohms. 150 however, is a little more adventurous.

Just out of interest, what fuse rating does it have? (not listed and is unclear from the picture) looks like a red standard blade fuse, but that would only be 10 amp. If its a red maxi fuse then thats 50 amp.

going on the simple calculation P = IV where I= current and V= voltage, typical operating voltage of a car alternator is 14.5v with engine running, and max current according to that fuse is 50A.

that gives a 725W power, however thats assuming 100% efficiency. depending on the class of amp, i would guess its class A or Class B since its designed to run ful range speakers as well as subs, then typical efficiencies are about 70%, although can be less.

So, 725 x (70/100) = 507.5 w Rms max. now thats believeable at 2 ohms, and is not too far short of quoted figure above. It gives you 127W per channel at 2 ohm, or 63.5W pre channel at 4 ohms. still a decent amount of power.

if you assume efficiency of 80% then it comes even closer (580W max) but 80% + efficiencies are only achieved by class D amps, which are designed for running subs and sound really bad running full range speakers (basically they 'sqaure off' the signal, making it easier to transmit, but also distorting it, which is not as noticeable with bass.

just for comparison, my big mono block amp i mentioned earlier has 4x 20 amp fuses, so 80 amp total rating. its also a class A/B despite being a bass amp (hence it sounds unbeliveable with a good sub like an alpine or an infinity).

so, P = 80 x 14.5 = 1160W

1160 x (70/100) = 812W rms at 2 ohm, 406 rms at 4 ohm. :P

Also, don't be fooled too much by all the gimicks, tryign to run any amp with 'virtual' (the 6 speaker theatre mode) channels, even when there designed for it just doesnt work. Its very hard to get things balanced, and the amp has to work far too hard and they just overheat and usually end up clipping, which is very likely to fry the speakers and the amp if run for long.

[The enchanted broomstick]

this seems to be turning into a bitch-a-thon contest of who "claims" to know the most lets just stop it there. Oh and for the reference its a 40amp fuse.

stu :P

[nmt_oli]

Sorry if im bitching, its just i hate all the false power figures that are always thrown around with car audio. pretty much no manufacturer quotes true values (apart from real high end stuff).

That amp looks ok, and im sure it sounds fine, im just saying its been hyped up. I would rather go for something cheaper by a slightly more well known company. at least i then know where i stand.

I only have done one full install so far, in my dads chevy van, and it has a calculated rms value of 1200w total and its a system comprising of 6 speakers (4 fronts , 2 rears), and 2x 12" subs, everything amped.

It may not sound a lot of power (in fact less than you were quoting for your one amp) but you can't sit in the van at full volume, its too loud, and theres no distortion.

Edited November 24, 2005 by nmt_oli

[The enchanted broomstick]

yup i know exactly what you mean there.

If anyone knows where i can find a DC to AC power converter i can chuck my PA stuff in my car, one of my uncles mates did it and it sounded awesome but it blew the catch off for his boot :P

The problem is trying to find a converter that can handle a TRUE 1300w RMS power so far i've only found them up to 750w which wont quite cut it.

stu :)

[CurtisRider]

stu that would rape your battery...............

[nmt_oli]

The other problem with AC converters is that the AC power leads produce a lot of signal interferance(due to magnetic fields and magnetic induction), you have to be very carfeul with lead placement, i i found out when i tried to run a playstation + screen in the the van. you have to keep the AC power loeads well away from any signal or speaker leads.

Edited November 26, 2005 by nmt_oli