This shouldn’t be thought of as an expensive LOC – it should be thought of as a low-cost EQ-correcting DSP, with an LOC built in!

What is it?

An advanced correcting DSP hiding inside a two-channel active Line Output Converter.

What’s it cost?

Retail $130, I’d sell it for more.

The Pluses

Auto-EQ correction, auto-all-pass-filter correction, high-voltage signal capability, basic Low/Mid/High signal content indicators, ridiculously low price.

The Minuses

Not ready to install out of the box, poor documentation, slightly complex setup with sensitivity to overload, ridiculously low price

Kicker KEYLOC out of the package

Why we tested it

It does some really cool things, at an unheard-of price point!


The KEYLOC comes in a small cardboard box – not a blister pack – so it needs to be in the stockroom, it can’t hang on a hook. In the box we found a wiring harness, the device itself in a plastic bag, a quick reference guide, and a few odds and ends.

OK, I said it does some cool things. What, exactly?

The first cool thing the KEYLOC can do for you is detect what frequencies are available on the speaker wires you have found. Kicker calls this Passive Frequency Detection, and it’s basically a three-band RTA – bass, mid, and treble. This is good for installers who don’t have RTAs, so they can make sure they aren’t about to try to get subwoofer signal off of midrange speaker leads, for example. (It’s better to have an RTA, of course!) The LEDs on the top of the unit are used for this purpose:

Examples of the LED indications for Bass, Mid, and Treble signals using Passive Frequency Detection

I tested this function and it works as advertised.

Another cool thing is that, unlike many Line Output Converters, the KEYLOC can handle 40V signals, making it a great choice for use with high-voltage subwoofer signals found in many premium systems.

The next cool thing it can do for you is undo OEM Equalization even if the signal isn’t full-range. This is very useful, and not all correcting processes will do this (some hang up without a full-range signal and don’t give you anything useful). This is especially useful when adding a subwoofer. Many OEM subwoofers are undersized, and so the signal sent to them has very-low-frequency content attenuated.  Often, a higher frequency, say 60 Hz, is boosted in an attempt to hide the missing low bass. In OEM systems without a subwoofer, that low bass is often attenuated to keep the factory speakers from ripping themselves apart. The KEYLOC can deliver a signal either flat all the way across the band, or much closer to that than you started with, so you can get better sound from a subwoofer add or a full-range system.

The last cool thing it can do is optionally defeat OEM all-pass filters present in the signal. If you don’t know what those are, basically it’s a technique OEMs often use instead of delay, which works in a limited fashion for both front seats by manipulating phase at certain notes.  I said “can” because that function of the KEYLOC is selectable. Why? Well, in most cases where you’re using a KEYLOC, you probably aren’t using any additional DSP processing downstream, so you probably want to keep those OEM all-pass filters working for you. They’re there for a reason, and while we may not think it works as well as our high-end systems do with delay applied, it works a lot better than doing nothing to correct for car’s off-center listening positions.  If you’re using a KEYLOC in front of a tuning DSP, such as a Kicker IQ Series DSP amplifier, then you may want those all-pass filters corrected so you can then use delay afterwards (we can’t effectively use delay on channels not in phase with each other at all frequencies).

(No, I didn’t forget that it can also undo OEM delay and align the two channels in time – I just don’t think it’s all that useful. OEM delay is pretty rare.)

It should be noted that – like other, more costly DSPs which automatically address all-pass filters – it isn’t intended to correct them all. When multiple all-pass filters are used too close together – I took this as code for “the way Bose does it”, but that’s my interpretation – the KEYLOC won’t succeed at defeating all of them. The problem is too complex. I find that to be reasonable, and that should be taken into account when using this device. Simple Phase EQ in Toyota, Subaru, and Hyundai OEM head units – that’s meant to be fine. Complex Phase EQ in a Bose system? Well, I haven’t tested it in a Bose system, but based on the guidance I’ve been given, I wouldn’t bet on it.

Installation and Results

So, I purchased the KEYLOC at retail – this wasn’t provided as a review sample. I opened the box, and found a “quick start guide” of sorts, with a QR code on it which gave me access to a more detailed manual online. I read the quick-start guide first, but it was very difficult to see. I know I’m 54, but I don’t need reading glasses very often. I did for this. Here’s a pic of the quick-release guide with my gain screwdriver on top of it for reference, so you can see how small the type is:

The quick-reference sheet (screwdriver for scale)
The text on the quick-reference sheet was awfully small (gain screwdriver for reference)

Then I used the QR code, opened the manual in a browser, and read that manual. That manual explained to me I needed to download three files from the Kicker website. I went to the website, found them, and clicked “download”. Well, one of the files I selected was a 22-minute WAV file, and that was going to take approximately 9 years to download – so it kept failing. I went back to Kicker’s site and selected the .mp3 version of the file rather than the .wav version of the file. That downloaded instantly.

There was little guidance on why I might select one or the other, or what the effects might be for one or the other. I’d recommend this be explained somewhere (I was later  assured that in their testing, no one could hear the difference, and that’s encouraging). It turns out that there are other test tone files you also need to install this device successfully, and those weren’t on that list of three. You will also need various sine wave tracks and full-range pink noise. I recommended that something like this be added to the front of the manual:

When I made my CD with these, I didn’t play close attention to the track sequence. My CD-burning utility jumbled the sequence of the tracks. When I tried to use them, I couldn’t get things to work properly. I eventually went back to the PC and saw the different track sequence on the software I went back and used the proper tracks in the proper order, and then it worked fine.

A burned CD with the calibration files
I burned a CD for the calibration files

This is important for you to know beforehand! Technicians in our industry – especially in some of the high-volume install bays – are used to taking the product out of the box, ready to go. The KEYLOC is NOT ready to go UNLESS you have the needed test tones on a USB stick or CD (and it’s really helpful if you have them in the proper sequence).

OK, once I got that handled, I proceeded to connect it to a head unit and calibrate it. Or, try to. Turned out I still had problems. Sometimes the instructions didn’t match up to what the LEDs on the unit were doing.

Fortunately, I know Joe Hobart in Kicker engineering well enough to text him on weekends, and he recognized the issue – when I used the QR code, I had downloaded a pre-release version of the product manual. He emailed me the latest version. (It’s hard to tell them apart, because Kicker oddly doesn’t put revision identifiers or dates on their documentation, which is decidedly not “best practice” in documentation creation). The QR code should now take you to the current version of the manual. However, you can’t check, because the updated version of the manual still lacked any date or revision number. You’re killing me, Smalls!

The instructions tell me to test the head unit’s output to make sure it isn’t clipping, and set the volume below the clipping point – or, to set it at 75%. So, trying to do what many technicians would do, I set it at 75% – as it said in the manual… And I proceeded to fail on every calibration I did!

Turns out the head unit I was using clipped below 75%. Even checking the signal at 1kHz with an o-scope – what many installers do to test signal voltage – didn’t help, because it was clipping in the bass. Due to the heavy EQ in the bass, it still gave me a clipped signal in the bass even when 1kHz was fine. That’s why I always recommend that you use an RTA to test the signal before you decide on which sine wave track to use to test. Well, the KEY LOC isn’t intended to require an RTA first, so the installer won’t necessarily know that. You could turn up the volume slowly during the Passive Frequency Detection process and watch which LED comes on first. If it’s bass, then use a 40 Hz tone as well.

So I needed to use test tones and an o-scope to ensure I wasn’t getting into clipping. I know how to do that, but many techs don’t, and the manual didn’t make it clear how important this would be, or how to do it. For that reason, I recommend the manual online also tell you how. I actually decided to test my head units at 50, 160, 400, 1k, and 8k, since those are the sine tracks on the Audiofrog Test CD. The GainMatch track from the Kicker test tones also sweeps sine waves from lows to highs for this purpose.

I first tested with an aftermarket head unit with the bass, mid, and treble tone controls randomly bumped and dipped to create a goofy response. Well, that turned out to be the one with problems with clipping in the bass. Fortunately, I got ahold of another OEM head unit, so I am throwing out the results with the aftermarket head and only reporting the results with the outputs of these two OEM heads, and then an OEM subwoofer channel emulation – an aftermarket head with a DSP amplifier downstream, adjusted with crossovers and EQ.

Head Unit #1 – 2010 Toyota FJ Cruiser head unit, non-JBL (same radio as the Tacoma of that period, but possibly different EQ)

The bench-test setup with the Toyota FJ Cruiser OEM head unit
Test setup, Toyota FJ Cruiser OEM head unit
The uneven frequency response from the Toyota FJ head unit
The output of the FJ's speaker-level outputs on the RTA

This radio has plenty of EQ applied – lots of treble boost to force those 2.5” dash speakers to play highs, and some subsonic filtering to keep those OEM 6x9s out of trouble. It does not have any Phase EQ or all-pass filtering.

You can see there’s a lot of bass boost at 80, no signal at all at 20 or 25 Hz,  almost nothing at 31 Hz, and 8dB of treble boost.

First, the clipping tests.

Now, because I’ve done this a few times, I set the balance and fader of the OEM head unit to center before I performed the calibration. That should be in the manual, though.


Clipping Point

50 Hz


160 Hz


400 Hz






No clipping at 1000 Hertz
A 1000 Hz sine wave on the NTI scope
No clipping at 50 Hertz
A 50 Hz sine wave on the NTI scope
No clipping at 160 Hertz
A 160 Hz sine wave on the NTI scope
The signal is almost flat on the RTA
The Toyota FJ head unit output, after correction by the KEYLOC

So, our calibrations were performed at 48 clicks.

Here’s the results after our calibration:

This is a huge improvement. The bass isn’t flat to 20 Hz, but let’s face it, neither are our subwoofers. It’s about 3dB dB down at 31, and that’s darned respectable. This would definitely improve our results with either a full-range system or a subwoofer add.

Head Unit #2 – 2018 Toyota Tacoma non-JBL

Bench-test setup for a Toyota Tacoma head unit
Test setup with the Toyota Tacoma head unit

The Tacoma is becoming well-known as the most popular vehicle we see in North America with Phase EQ (all-pass filters) active (there are also other Toyotas, some Subarus, and several Hyundai/Kias, as well as many Bose systems). Like the previous radio, this has plenty of EQ, some subsonic filtering, and some treble boost

Here’s the left and right channel before correction, and the two summed together (showing the area the two channels are 180 degrees out of phase, due to the Phase EQ). The left and right have different EQ applied, so I am showing both of them.

The uneven frequency response out of the left front channel on an RTA
Left-front channel of the Tacoma on the RTA
The uneven frequency response out of the right front channel on an RTA
Right-front channel of the Tacoma on the RTA

Here are the clipping results:


Clipping Point

50 Hz


160 Hz


400 Hz





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When we sum left and right togeher, the resulting “hole” at 250 shows that the two channels are at or near 180 degrees out of phase at that frequency
Left and Right summed shows a big phase cancellation at 250

We did our calibrations at 49 clicks. More on this in a minute.

The correction process probably took twice as long as the FJ radio.

Here’s the corrected response I got the first few times I tried it, and the corrected summed response:

The early calibration attempts with the Tacoma were uinsuccessful, as this RTA screen shows
The uncorrected left-front channel of the Tacoma head unit, after our first calibration attempt
The early calibration attempts with the Tacoma were uinsuccessful, as this RTA screen shows
The right-front channel of the Tacoma head unit, after an early calibration attempt

Well, that’s definitely not as good!

So I tried several things, and it seems that, despite the lack of clipping indicators at 49 on the volume knob, and the lack of visible clipping with the o-scope, we got MUCH better results at 20, 40, and 45 clicks than we did at 49! Here’s what we got at 40 clicks:

When we lowered the volume even more, we got a successful calibration, as this RTA screen shows
The flat output of the KEYLOC after successfully correcting the Tacoma signal

The sum of the two corrected channels shows that the large out-of-phase condition around 250, caused by the all-pass filter, is now gone. There is a very narrow out-of-phase condition at 500, which causes a medium dip visible in the screen, but it’s still tons better than before (if you want that to be corrected – in most cases, I’d keep it!)

Summing the corrected channels together shows some slight out of phase issues, but the major cancellation is gone
The major phase cancellation in the summed Tacoma signal is gone!

What that tells me is that my recommended practice is still the right way to install this sort of product – always check your work. Plug the outputs into an RTA and test the signal after you’re done, because you might need to lower your volume knob to a setting slightly BELOW 75% and run calibration again. And you won’t know, unless you check.

“Well, can’t I just calibrate at 50% every time?”

Not if the head unit has auto-loudness, like this Toyota did. You want to calibrate at as high a volume setting as you can, so that the response is flattened at high volumes, and then the auto-loudness will work for you as you turn the volume down.

Here’s what we saw at low levels, after calibrating at high levels:

Turning the volume down causes the Tacoma head to boost the bass and treble in a common “auto-loudness” manner
The Tacoma auto-loudness function at work

This is auto-loudness, and that’s fine, we don’t want to fix that. It simply makes sound systems sound better at lower volumes. However, you don’t want the reverse of this. You don’t want a flattened signal at low volumes, and then a signal at higher volumes where the bass and treble both drop off.

Head Unit #3 – OEM Subwoofer Channel Emulation

In this scenario, I connected an aftermarket CD player to an 75WPC aftermarket DSP/amplifier. I configured a pair of the DSP amplifier output channels as an imitation OEM subwoofer signal. I low-passed it at 100, and high-passed it at 32 – both at 24dB/octave slopes. I boosted the signal at 63 using the EQ. This gave us a signal that looked a lot like OEM subwoofer signals I’ve seen.

This signal is intended to copy an OEM subwoofer signal, with a steep lowpass, a steep subsonic highpass, and a boost at 63
The OEM-subwoofer-emulation signal - missing lows, big peak!

The first few times I tried to get a calibration, what I got looked pretty much like what I started with:

Attempting to correct this signal at too high a level gives us this largely unchanged signal
Again, a failed calibration’s resulting output - largely unchanged

I checked again for clipping, three different ways, but neither my o-scope with test tone tracks, my o-scope playing the Kicker sine-sweep track, nor the KEYLOC’s internal clipping indicator thought I was clipping the signal.

Regardless, the calibration hadn’t “taken”, so I did it again with the head-unit volume turned farther down. This time, it worked:

Lowering the volume more allowed a successful calibration and a wider, flatter signal on the RTA
A successful calibration of the OEM-subwoofer-emulation signal - wider and flatter!

Now, that’s a solid improvement! If you have a subwoofer, it’s hard to say that the uncorrected signal (probably intended for a 6.5” or maybe an 8” sub) wouldn’t sound better on a high-performance 8”, 10”, or 12” subwoofer from the aftermarket.


Just like every other automatic-adjusting device I’ve ever used, I wouldn’t use this one without testing its output after its calibration step. If the output isn’t what you want, I would turn the volume down a couple clicks and try again. Otherwise, you run the risk of having used an advanced DSP correction device, and getting no correction applied to the signal.

I think it’s pretty obvious, based on the Passive Frequency Detection feature, that Kicker wants this device to be useful to installers who don’t have an RTA. Well, in the words of Denis Leary: I wanted to play center field for the Red Sox – life sucks, get a helmet. Successful OEM Integration requires tools.

A word about the documentation

Now, I have written several dozen manuals for various kinds of products – audio, security, video, even service manuals for FAA-certified in-flight multi-zone entertainment systems –  and I know it’s harder than it looks. I’ve also done years of tech support, and I’ve taken lots of tech calls which could have been avoided if someone had done a better job on the documentation. I found the KEYLOC to have incomplete and misleading documentation – that applies to the quick start guide and both installation guides I received – and that may make it difficult for the installer to get the results it’s capable of delivering. On top of that, as a document, I found the quick release guide to be impossible for anyone over 35 to see, and I found the text layout, line spacing, and illustrations included in the online manual – well, that just looked like a lousy job. The manual is part of the product, just like the hardware. Now, the day I finished this review, I saw that Kicker updated the online manual to some degree, and had followed some of the recommendations I had made, but it still has significant opportunity for improvement. I hope that Kicker continues to update the manual to a level that the product hardware merits – I like the product hardware, and I would definitely use it in the field.


Why did I call it a “ridiculously low price”? Because many shops are now $100 an hour or more for installation labor. In my opinion, this device requires use of an RTA to ensure that the calibration has been successful – otherwise, you run the risk of going through all that work and getting a signal that’s not much better than you started with! The complete installation is likely to take 60 minutes or more (setup alone can take 20 minutes in some rare cases, based on how long the FullTest track is), and that’s not counting any test-track downloading or CD-burning required.  All that means that installation time may cost as much as the device (and that can make for a harder sale)!

At that price, salespeople and technicians may underestimate what it takes to install this device. It’s not an LOC from an installation point of view.

Also, understanding when a device like this might be needed and knowing how to explain the benefits might be worth more than the gross profit dollars available at $130 retail.

Charge 20 minutes’ worth of install labor for an hour job, and then give the installer a confusing and incorrect set of instructions – and a product that’s not ready to install out of the box? Whatever that’s a recipe for, it’s probably not tacos. If you’re going to carry this really cool piece of gear, you need to have the files downloaded and ready, and you need to understand how it works.

This shouldn’t be thought of as an expensive LOC – it should be thought of as a low-cost EQ-correcting DSP, with an LOC built in!

I would use this with add-a-sub installs as an upgrade – especially with clients asking to move their sub and amp from one car to another. I would also use it in many basic amp-and-speaker upgrades – but probably not at list price. I’d bill for physical installation and then for setup as two tasks.


Delivers solid functionality that nothing else close to this price can deliver. Requires preparation before install, and more time than other LOCs, but the results are worth it.

Suggested Uses

  • Add-a-sub systems – handles high voltage, extends low-end response, flattens OEM “one-note” bass boost
  • Adding amplifiers to full-range signals out of OEM head units   undoes the OEM EQ automatically, especially when there aren’t all-pass filters to deal with
  • Adding amplifiers or DSP to partial-range signals out of an OEM amplifier – undoes the EQ, shifts crossover points farther into the stop band

Educar Scores

Return on Investment

It has a decent return, but there’s only $130 in $130.

Degree of Difficulty

More difficulty in the install process than I think they intended.


It is VERY useful!