Today in product reviews, we’re talking about the Connection Sli 2.2 passive Line Output Converter. I hoped to test one of these out early in the year, but as you may have heard, 2020 has been awkward.

Full disclosure, I have Elletromedia as a client, but I didn’t get paid to do this, and they didn’t know I was doing these tests.

This is a passive Line Output Converter in Elettromedia’s Connection line. Big deal. Passive Line Output Converters have been on the wane for a few years. They have a bad reputation for introducing noise, rolling off in the bass, and generally damaging the sound. Active LOCs have been growing in popularity the past ten years.

Well, this may very well be the best passive LOC I’ve ever seen.

The reason I was excited to see it and test it was, the specs say it can handle 35V RMS. I have seen some other LOCs (all active) SAY they can handle that kind of voltage, but some clip the signal pretty badly while doing it. I think this is the biggest reason for the growth in popularity in active LOCs, is the rare cars that will melt a $20 passive LOC.

I put it on the bench and connected it to the outputs of a subwoofer amplifier, and the SLI2.2 didn’t clip at 35V at either 50 Hz or 1kHz. That’s about where my power supply was giving up, so I didn’t go past redline on this run, but it definitely works as advertised. This makes it the only passive LOC I know of which can be used on the high-voltage subwoofer channels in some BMW, Range Rover, Maserati, Jeep, etc.

I also tried out my NTI XL2’s ability to measure THD. I saw two-tenths of a percent until we got into clipping. Of course, some of that was the amplifier going into it! This is a device that doesn’t trash the sound going through it – they weren’t kidding on the website when they listed “Excellent Sound Quality” as the very first bullet point!

It has Audison’s USS circuitry built in. That’s Universal Speaker Simulator, and it is there to “fool” OEM muting circuits into thinking that there’s a speaker still connected. Unlike some other loading approaches, it won’t stop working next year if Chrysler changes their threshold again.

That’s a great list of features. All that said, I noticed several other things about it.


It’s solid. The box it’s in is metal. I’m sure that helps with some heat sinking in high power applications, but it also is just a solid piece of gear. I always like gear I can hand to a client and have them feel like it’s something sold and worth money. I don’t like that many LOCs  look like alarm shock sensors.


The end caps support mounting this properly.
It’s mean to be installed, not stuffed behind a radio.


It can be used in ART remote-turn-on generating mode, or not.
The instructions clearly explain that you don’t need power or ground if you’re not using ART.


It has good instructions.
They aren’t available on the website, unfortunately.


The harnesses has the inputs, the outputs, and the power wiring in one connector, with strain relief molded into the harness. Most cheap LOCs either have wires flying off the PCB, or crappy connectors.


The harness uses standard EIA speaker-wire color codes.


No pots. Two dip switches is it. High or low changes the attenuation from 4:1 to 8:1.


A wiring diagram is on the bottom of the unit if needed.


The transformers in the unit are shielded with grounded metal cans soldered to the ground plane. This is the same approach used in very expensive ground isolators used for the pro market, where inducted noise is simply not permissible. This unit certainly looks to be much less likely to pick up noise from wires next to it in the car than other passive LOCs. The two transformers are also much less likely to affect each other inductively due to the metal cans, and that means better stereo separation. More on this in the next point.


The transformers are separated more than usual in these types of devices. Not only are they shielded, they are as far apart as possible on this board. That means that stereo separation is preserved as much as possible. Look at a cheap LOC. The transformers are like half a millimeter apart, and their magnetic fields affect each other and reduce your stereo separation markedly. This doesn’t matter in a sub add, but it definitely matters in a full-range installation.


It is a 2-channel LOC, but it is a 4-channel USS loading interface. That’s why it has 4 sets of speaker input wires. (The other two channels also will activate ART turn on generation). If your OEM radio needs to “see” all 4 speakers, you can easily load the rear speakers or a mono center speaker, even if you aren’t using them.

Elettromedia also makes a version called the Connection SLi 4.2. I didn’t test it, but I’m sure it shares all of the above qualities.

I would definitely keep both the SLI 2.2 and SLI 4.2 around for add-a-subs in Chryslers and BMWs, and full-range applications in front of both amps and DSPs without speaker-loading built in. It costs more than a cheap LOC, but that’s because it’s better.