JBL Stadium subs with switchable impedance.....could someone explain how these work?

[98 SNAKE EATER 10+ year member]

After a bit of debating what sub(s) to add to my Sienna's factory JBL system (see old thread link), I decided to go with a single 12 mounted in a custom glass stealthbox that fits in a rear pocket meant for the 8th seat storage

Two 8's, one 10 or one 12?

Looking to add a little more bass to my 2016 Toyota Sienna It has a factory 10 speaker JBL Entune system with DVD/BluRay and RES First off, I'm not a bass head by any stretch (outgrew that phase a LONG time ago), but I do like nice clean thump (especially when watching movies) Loud is good...

www.caraudio.com

(work in progress)

The sub I chose is a JBL Stadium 1224 that has a switchable impedance from 2 to 4ohms

Can anyone explain how exactly they're able to do this?

Click to read more...

 

[THATpurpleKUSH 5,000+ posts]

Dual voice coils with a switch. Nothing new and ground breaking, manufacturers have used various methods to achieve a switchable impedance for at least the past decade.

 

[98 SNAKE EATER 10+ year member]

Dual voice coils with a switch. Nothing new and ground breaking, manufacturers have used various methods to achieve a switchable impedance for at least the past decade.

Ok, could you tell me how they're able to achieve either a 2 or 4ohm load?

I've seen other switchable impedance subs that switch from either 2 to 8ohm, which would be simple on a 4ohm DVC sub that uses a switch to go from series to parallel, but this sub has me stumped.

At first I thought perhaps the switch would just cut one of the two coils.

Like if it was a 2ohm DVC wired in series to get 4ohms and the switch would just disable one coil to make it a 2ohm load....

Or if it was a 4ohm DVC wired in parallel to get 2ohms and the switch would just disable one coil to make it a 4ohm load....

But of course, if this was the case, it would cut power handling in half and it wouldn't be nearly as efficient.

Next thought was perhaps a resistor built into the switch, but I can only imagine what kinda heat issues that would cause.

I actually contacted JBL/Harmon directly and none of their reps could give me a straight answer as to how it's done.

 

[Slo_Ride 5,000+ posts]

It's either 2 or 4 bro, that how dvc's work.

Basic Car Audio Electronics

Car audio technical information with more than 125 individual pages, 50+ calculators and wav files. The covered topics range from basic electronics theory to more advanced topics such as speaker impedance as it relates to frequency, damping factor and signal to noise ratio.

www.bcae1.com

 

[98 SNAKE EATER 10+ year member]

It's either 2 or 4 bro, that how dvc's work.

Basic Car Audio Electronics

Car audio technical information with more than 125 individual pages, 50+ calculators and wav files. The covered topics range from basic electronics theory to more advanced topics such as speaker impedance as it relates to frequency, damping factor and signal to noise ratio.

www.bcae1.com

Umm, no

If you have a 4ohm DVC, you get either 2ohm wired in parallel or 8ohm wired in series (like this)

If you have a 2ohm DVC, you get either 1ohm wired in parallel or 4ohm wired in series (like this)

This DVC sub somehow switches from 2ohm to 4ohm

How?

I dunno

 

[Slo_Ride 5,000+ posts]

Lulz.

 

[THATpurpleKUSH 5,000+ posts]

It's a resistive switch.

 

[Slo_Ride 5,000+ posts]

Switch is totally pacifist.

 

[98 SNAKE EATER 10+ year member]

It's a resistive switch.

Not doubting you as I'm still rather clueless about this, but the switch on mine doesn't appear to have a resistor bank, just looks like an ordinary switch board with some really dinky lookin wires

That being said, I just found this old Sonic video introducing an Infinity Kappa sub with SSI (I believe they share the same switching setup), but they claim to have a triple voice coil in order to switch from 2 to 4ohms