Hi

Joel or similar might grasp this one, but its still a little weird in my mind.

I've got two new 12w3 D4s on their way to me now, but an issue with the way they'll be setup cropped up, and a bloke at the audio shop tried to explain it to me...

I run two kenwood 460w RMS amps, at 4ohms, now because these new JL subs are dual voice coil at 4ohms, if I use one sub per amplifier it will show it 8 ohms which is not good. The best way to do it is to apparently wire BOTH subs into one amplifer, using the bridged ports, to show each sub 230w RMS at 4ohms. (ran in series, not parellel, I think were the chaps words... :confused: )

Anyone like to comment?

Also, where'd the ICE section go to?

Jason, heres your ICE section

http://www.briskoda.net/forums/f31-ice-&-technology-gadets.html

Well, if it gets moved then.

Hi

Joel or similar might grasp this one' date=' but its still a little weird in my mind.

I've got two new 12w3 D4s on their way to me now, but an issue with the way they'll be setup cropped up, and a bloke at the audio shop tried to explain it to me...

I run two kenwood 460w RMS amps, at 4ohms, now because these new JL subs are dual voice coil at 4ohms, if I use one sub per amplifier it will show it 8 ohms which is not good. The best way to do it is to apparently wire BOTH subs into one amplifer, using the bridged ports, to show each sub 230w RMS at 4ohms. (ran in series, not parellel, I think were the chaps words... :confused: )

Anyone like to comment?

Also, where'd the ICE section go to? [/quote']

Ok , on each sub you have two 4 ohm coils.

You can use a separate channel on an amplifier to drive each coil , so 4 channels in total each one with a 4 ohm load.

If you are planning on using both of the kenwoods then thats how I'd do it.

The other alternative is to connect the two coils together.

If you put them in series then you have an 8 ohm load for each sub.

Using the kenwood amps in bridged mode you could drive the subs if they were connected in series quite easily but as the impedance has doubled the output of the amp will have halved from what it would be at 4 ohms (with me still?) but you stand no chance of toasting the amp

If you put coils in parallel you have a 2 ohm load for each sub.

I'm pretty sure the kenwood is stable at 2 ohms when bridged , and if so then it will have a higher output because of the lower impedance. If it's not designed to run at 2 ohms though it will damage the amp to be driven hard when wired like that.

If you are only going to use one amp to drive both subs then you would wire the coils in series on each sub then connect the subs to the amp in parallel to end up with a single 4 ohm load.

Cheers Alex - might get more advice when it comes to wiring up time I've only ever "plugged and played" subs before so this will be something new for me.... Originally I was just going to wire one sub to one amp, in bridged mode, but this is what I'm led to believe will lead to the 8 ohm situation....

If you're going to wire one per sub follow image 1 which will show the amp 2ohms producing the most power. This is connecting the two voice coils of the driver in parallel (+ to +, - to -).

If you're going to wire both subs to one amp then follow image 2 which will show a 4ohm load to the amp which is the safest load, but all depends on what your amp/s stable limit is. This is connecting the two voice coils of each driver in series (+ to -) and the drivers themselves in parallel (+ to +, etc.)

Hope that make's it clearer for you.

Yes , those diagrams are correct.

Of course you need an amp that is stable at 2 ohms to wire things up the first way , although I'm pretty sure the kenwood concerned is capable.

Yes ' date=' those diagrams are correct.

Of course you need an amp that is stable at 2 ohms to wire things up the first way , although I'm pretty sure the kenwood concerned is capable.[/quote']

You have the third one of these amps, don't you Alex?

I looked up some stats on the net, and it says "2 ohm load capability" - Now I assume this means its stable at 2 ohms.

Now the worrying thing is am I going to quickly fook up my JLs putting that sort of power through them? 300w RMS subs should be fairly strong though? I just wonder what sort of RMS figure my amps will put out under 2 ohms, if they are capable of doing 460w RMS at 4ohms (bridged)

Its the KAC7201 if anyone fancies doing some research?

You have the third one of these amps, don't you Alex?

Yep , but mine's just bridged into a single 4 ohm sub , so not really taxing it much.

I looked up some stats on the net' date=' and it says "2 ohm load capability" - Now I assume this means its stable at 2 ohms.[/quote']

Yes , I've also checked since and it looks like it will be fine at 2 ohms.

Now the worrying thing is am I going to quickly fook up my JLs putting that sort of power through them? 300w RMS subs should be fairly strong though? I just wonder what sort of RMS figure my amps will put out under 2 ohms' date=' if they are capable of doing 460w RMS at 4ohms (bridged)[/quote']

From what I can see it's actually 460w RMS into 2 ohms , so it would have been less than that (around 300w RMS probably) into 4 ohms bridged.

You won't damage your subs (just your hearing) unless you are a complete muppet as subs getting too much power has a very obvious distortion to it , plus the tell-tale thwack as the magnet hits the end stop

Jason do as AVRS says thats the best way your amps are 2 ohm stable..... if it was my car id ditch the the amps and buy one big one and run both... i said to you before you got your RF amps....

DR. connecting the seprate voice coils to seprate channels is not recomended they are designed to be wired together never sepratly to individual channels on an amp. the reason is not all channels on an amp give out the same output, eg signal time slightly diffrent watts diffrent etc.... potencially causeing one coil to move and be powered diffrent as you can imagine thats not good !!!!

Joel

This link seems to say 460w RMS x 1 (bridged) at 4ohms.

http://www.audio-warehouse.com/web/mdl/KAC7201/detail.asp

Joel - I'm tempted to do as you say, but I can't really spend any more money on my system, and quite like these Kenwoods. The RFs have all gone now, but they were all too weak to consider using. I will try running the dual coils wiring in series, one to each amp, but am still a little worried about cooking....

To be realistic even if you're amps do give out 460w it won't trouble the subs too much, coz the JL's are very capable of taking 500w of clean power. Just make sure you don't clip the signal. You're amps will probably be giving out closer to 400w in real life as many manufacturers such as Kenwood, Pioneer, Sony and similar always slightly over rate their outputs. While JL, Phoenix Gold, Morel and so on always under rate their products so people use them carefully and give them clean power. As an example, I've got a Kicker amp putting out just under 800w RMS into a Morel sub rated at 400w RMS but it happily eats it up.