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Discussion Starter · #1 · (Edited)
This thread is all about the 6 speaker factory stereo in the 2021+ K5 GT-Line.

If you have information to share about a Bose system please create an additional thread and share the link so I can add it here in the top. The systems are very different aside from door speaker and tweeter sizes. It could get pretty confusing if we’re throwing around specs for both systems in the same thread.

I'm pretty particular about my music... a snob, some might say. I wouldn't call myself an audiophile as I don't purchase $800 speaker wire or HDMI cables BUT I am pretty critical of the musical fidelity in my car, my house, my headphones, live performances, you name it.

While shopping for a new car I had narrowed it down to a couple and was back and forth test driving and listening. I'm no stranger to customizing stereos so the only real requirement was that it wouldn't be terribly difficult to modify and the signal sounded clean (no obvious distortion from the speakers at high volume).

Researching anything on the K5 was/is difficult since it's still pretty new. I really wanted AWD since I live up north and the dealer offered me a good price so BAM, there I was with a brand new, great looking vehicle with a ****ty sounding stereo :LOL:

The tone wasn't terrible for OEM but the music felt very disconnected no matter where you sat. When listening to certain songs, parts of them had hollow sounding voices and other bits that made my head feel like it was in a vacuum. You can hear this affect by popping on some headphones/earbuds and listening to this track at around 40 seconds.

It wasn't this extreme all the time, just certain songs were really bad.

I always modify my stereos to make them as "SQ" as possible. If you're looking for a soundstage with well placed voices and instruments, stick around. If you plan to install 4 15" subs so it sounds like a gorilla's trying to escape your trunk, this info will also be helpful, but you can skip down to the subwoofer post (when it’s written) to expedite the process.

Also, I will fill in the placeholders in the coming days. There's a lot to share!

Ok enough yapping, let's get into it. There's a lot to unpack here. Apologies if this is too in depth... These are all the things I would have loved to have known before I purchased the vehicle!

Section links as I complete them:
Factory Specs Overview
Headunit Measurements
Removing All Pass Filters
Volume Dependent EQ
General Wiring and Connectivity
Subwoofer Add-on
Door Speakers and Deadening
Center Channel
Basic DSP Settings
Speaker / Device Selection

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105 Posts
Discussion Starter · #2 · (Edited)

Output channels
: 4

Measured max output power:
Front - about 35 watts each
Rear - about 10 watts each

Before balking at this wattage, it's actually not bad. Thanks to the undistorted power it can be turned up really high. Assuming an average speaker sensitivity of [email protected] watt, you can easily reach over 100db with the factory setup. That's pretty damn loud for some door speakers/tweeters. Never tested the factory door speaker efficiency, this is just math in my head. Anyone care to share a measurement before replacing their gear?

Max voltage achieved from front channels of head unit: 11.6 volts
Useful info for selection of aftermarket amp(s), DSP, or line out converter

Clipping volume: According to my oscilloscope it did not clip, even at max volume, at any frequency, using a -5db 20-20kHz sine sweep. I tested with two scopes and still find it hard to believe. The tests were run with speaker wires connected to a 20k ohm resistor, not a speaker since I'm running headunit speaker wires to DSP high level input.

OEM speaker wire gauge: 20-22awg

Speaker wire colors:
  • Front left: + brown , - white
  • Front right: + blue , - red
  • Rear left: + black , - yellow
  • Rear right: + green , - orange
I did not verify tweeter wire colors or polarity as I didn't utilize the factory harnesses. The OEM tweeter wires do connect directly (in parallel) to the door speaker wires somewhere. I didn't care enough to track it down as I ran new wire to my aftermarket tweeters.

There may be a digital output somewhere on the radio. I didn't care to look for it as I wasn't willing to lose functionality like volume control on the steering wheel and radio as well as potentially lose navigation commands, hands free calling, chimes, etc. If you don't mind losing these features you could likely bypass all the BS detuning that follows.

Side note: If you can avoid removing the radio from the dash I would HIGHLY recommend it. It was a massive pain in the *** and felt like things were going to break. Most installs don't need it removed.


All are 4 ohms

Front Dash Tweeters - 1"
Front Doors - 6.5"
Rear Doors - 6.5"

Door speakers - None. They run full range but are incapable of producing much above 6-7kHz and start beaming around 2kHz
Tweeters - High passed @ 8000Hz 6db/octave with inline capacitor attached to tweeter. This is really really high for a two way setup.

Space behind door card window when rolled down:
Front - about 2.125"
Rear - about 3"

Depth of door card to door panel - about 1.125"

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Discussion Starter · #3 · (Edited)

As mentioned in my first post, I noticed some really weird sounding things while listening to a variety of music. My DSP has an input analyzer that helped visualize what was coming in from the headunit. I did my best to debone the factory EQ via the built in analyzer, by ear, and using sine sweeps and pink noise to locate problems areas. That was a massive waste of time as the DSP resolution and refresh rate just wasn't high enough for me to see the detail I was looking for while making changes live.

So, I bought a USB audio interface that allowed me to measure the signal coming from each channel of the headunit. Then, through the DSP, I was able to combine channels, invert them, mess with delay, phase, all pass filters, and eq in real time while measuring with REW to try to undo the factory tuning.

Here are the results of those measurements and I will reference them in later posts. These are electrical, not acoustical measurements, so you can ignore the db scale on the left, it's relative. Also, all non-Bose K5 measurements will be nearly identical unless an update is applied to modify EQ or a future model has some variation.

Front Left + Right Individual Channels: Measured identically, which was a relief.


When building an aftermarket system the frequency response would ideally be a straight line (left to right) or perhaps a slow, steady reduction in output as the frequency rises. The worst here is the massive dip in the sub (-20db!) and upper bass (-10db) regions. The peaks can be handled pretty easily with DSP but the huge dips are more of a challenge. More on this later.

Rear Left + Right Individual Channels: Also thankfully measured identically.


You can see the level is much lower than the fronts due to the reduce wattage available there. A lot of EQ is applied here as well but not as much as the front. Unfortunately, there are two huge -15db cuts at 135Hz and in low end bass (just like the fronts).

Now, here's where the USB audio interface helped tremendously. I was struggling to understand what was going on with my ears, DSP analyzer, and other manual methods. You can't see the issue when playing any channel individually, but it's very apparent when channels are combined.

Front Left + Right Channels Combined


See those five big, sharp dips? Pre-USB interface, what I heard and observed seemed like comb filtering (caused by delay) so I was trying to undo the delay. It was actually very close < 2k. Above that got shaky.

Anyway, those big dips are complete cancellations at the lowest points caused by these things called all pass filters. These filters alter the phase at the chosen frequency. They're often used to compensate for vehicle specific peaks and nulls with the factory stereo. These peaks and nulls are usually created by the acoustics of the car itself and all pass filters are often the best way to make it sound as good as possible for everyone in the car.

Rear Left + Right Combined


The rears have all pass filters as well, but only two.

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105 Posts
Discussion Starter · #4 · (Edited)

This is an optional step depending on your goals. BUT if you go all the way (replacing everything but the radio), removing these filters with a DSP completely fixed all the weird audio I heard in the factory setup! I would consider this an absolute necessity if you are adding time alignment, a center channel, and/or multiple seats tunes. Keep in mind that configuring and testing all this can be extremely overwhelming for those unfamiliar with tuning.

In additional to all door and dash speaker replacement, I wanted to add a subwoofer and a center channel (played only for passengers), both of which require the combination of left and right channels. As you can see in the previous post, when channels are combined, there are important frequency ranges that would be partially to completely nulled. 70-90Hz in the subwoofer region and several more would be effectively removed from the center channel.

Front Individual vs Front Combined Measurements


Before DSP all pass filters were applied.

Front Individual vs Front Combined after DSP All Pass Filters


After DSP all pass filters are applied. It's very close and I had some low frequency boost in this one. I have to dial it in some more. It sounds SO MUCH BETTER though. I didn't meant to capture the bass boost in the screenshot. I'll replace the photo it I can get them closer.

Rear Individual vs Front Combined Measurements


Before DSP all pass filters.

Rear Individual vs Rear Combined after DSP All Pass Filters


After DSP all pass filters. Nearly perfect match and almost complete silence with one channel inverted! Not sure that I care enough to tweak it much more since I don't have much volume going to them most of the time.

I'll come back and share the filters I landed on once I perfect them a bit more.

You may have noticed I haven't touched the EQ itself. The goal here is to match the right and left channels so they provide same input levels, eq, and phase.

I measure the drivers individually and then as pairs, then modify the curves to match each other. So long as there aren't measured acoustic peaks and dips caused by the factory EQ, I don't mess with it.

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Discussion Starter · #5 · (Edited)

Before we get to the next section, you should know about the built-in, unchangeable, volume dependent EQ curve. I did flatten the response with my DSP prior to measuring so the difference was easier to see.

At low volumes, bass and treble ranges are boosted. As the volume increases, these boosts are reduced and even cut at very high levels. Each line represents a volume knob increase of 6. So bottom starts at volume level 9, then 15, 21, 27, 35.


The bottom measurement (pink, volume level 9) has a 10-12db bass boost and a 5db treble boost.
The top measurement (red, volume level 35) has both boosts removed and even shows a reduction of bass.
I did not test higher or lower as I won't be outside of this volume range very often. Too dangerous or too quiet.

Our hearing is less sensitive to bass at lower volumes so this should benefit most of us. Tune your system at a moderate to high volume and it should scale well at lower volumes as well. Bass heads, you may be annoyed by this depending on your preferences.

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Discussion Starter · #6 · (Edited)

Some of this will not be news but figured many could benefit from the info. The following recommendations are for most people. If you're running a ton of power then a lot of these go out the window.

Wiring door speakers and tweeters

The factory door speakers and tweeters are connected by small gauge wire but won’t need replacement unless you are amplifying every driver and running at VERY high wattages. 20 gauge can handle at least 75 watts per channel with no degradation at short distances. Tweeters will only consume a few watts even at very high volume. The loudest tweeter I ever heard in action consumed about 13 watts peak at measurement. It was obnoxious :D

If you do run new wire from an amp, 16-18 gauge will suffice for 99% of installations. I used 18 gauge for my 75w/channel amp to the doors and tweeters. You also don't really need to change the wire going into the door.

Wiring subwoofers

12-16 gauge speaker wire for subwoofer installations. I’m running about 600 watts (max) and ran 14 gauge from under the passenger seat to the trunk since it’s about 8-10 feet of wire.

Amplifier power wire

If you’re adding an amplifier you’ll need power straight from the battery and an inline fuse placed as close to the battery as possible to protect the power cable from shorts.

I found the easiest place to run power into the vehicle was through the firewall grommet on the drivers side. You’ll need to remove the battery to access it easily. You can poke a hole with a phillips head screw driver. I installed 4 gauge and ran it from the inside into the engine bay as it was less to push through the grommet.


The power wire is running through the grommet just below that arrow pointing up. Since the hole as so small it was a very tight fit with nearly zero change for leaks. Pro-tip: grab some soapy water to rub on the cable as you push/pull it through the grommet. It'll slide through like buttah and will evaporate with no oily/greasy residue left behind.

Power wire isn’t as easy as “use 4 gauge”. The size of the cable depends on the distance from the battery to the amp and the current draw (not wattage) of all amps that will be connected to the cable.


How to use the signal from the headunit for aftermarket amplification.
There are a several options and limitations to getting sound where you want it if you wish to go beyond replacing door speakers.

Let's go over the limitations:
  • There are no low level connections (RCAs, for example) that you can plug directly into an amp or processor. You will need an amp or DSP with high level inputs, or line out converter (LOC).
  • There's a significant amount of EQ and all pass filters applied by the headunit. You would benefit from some type of processing to correct it.

Some of the options:
  • Amplifier with high level inputs and preferably some ability to boost certain frequencies. If you're using the amp for a sub, you'd want to be able to boost the low end quite a bit to make up for the OEM removal of bass below 50Hz. The all pass filters would remain and the 80Hz may be mute (see subwoofer section).
  • DSP with high level inputs. I have a Helix DSP which provides the ability to override the OEM all pass filters and EQ to anyone's preference.
  • Line out converter (LOC) before amplifier, DSP, etc. There are standard LOCs which simply convert the signal from high level to low level. This would allow you to easily connect an amplifier without high level inputs to the RCA inputs of any amplifier. However, all the factory EQ and all pass filters will remain. Note: LOCs only process two channels. If you want to keep front/rear fading then you would need two of these. Most people just use the front channels and disconnect the rears.

The ideal solution for most people looking to amplify anything would likely be a smart LOC. These perform the same function as a standard LOC, converting high level inputs to low level outputs, but ALSO provide some processing that can undo some or all of the factory EQ, speaker delay (not applicable in this K5 stereo), and all pass filters. There two stand out smart LOCs are the Audio Control LC2i and the Kicker KEYLOC.

Both are smart and can undo some of the EQ. Both have the great feature of signal detection which will sense when the radio is outputting something and will turn on your amps with a remote out signal. You don't need a remote input signal for either, which is great. One less factory wire to hunt down! They do both require a power source, which you would just grab from the power you ran to your amp(s).

The obvious choice for the K5 is the Kicker KEYLOC, It will undo the factory EQ, boosting the very low end and leveling out the rest of the EQ. More importantly, in my opinion, it will fix the all pass filters too so you won't have the 70Hz-90Hz (and several higher frequency) nulls. It's very simple to configure.

Here's a video showing how it works and what is involved for setup.

Getting signal from the headunit to your amps, DSP, or line out convertor (LOC).

While you can tap the wires behind the headunit, grabbing the front channels at the kick panels or the rear channels at the b pillars would be much easier. You can tap the channels without cutting using 20 gauge posi-taps.

I don’t recommend T-taps. They make a crappy connection and are especially problematic with small gauge wire.

I would suggest tapping the front channels unless your equipment can’t handle the higher voltage input (11.6v).

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Discussion Starter · #7 · (Edited)

The most commonly desired upgrade is a subwoofer. This can be easy if you’re content with the rest of the stereo and ONLY want to add a more bass.

Required parts:
A subwoofer (duh), appropriate cabling, and either of the following:
  • An amplifier* with high level inputs
  • OR An amplifier and a line out converter*

Placement testing:

The sub location, combined with the direction it's firing, the box type, and the sub itself will offer different sound characteristics. Bass travels through a car differently than other frequencies. The wavelegths are very long and will sound VERY different depending on the box size, type, and orientation.

If you already have a box with a sub in it, that's fine. Hopefully you can move it around a bit in the trunk. If not, borrow someone else's or build a junker out of leftover wood to test.

There are a few standard sub locations to install a sub in a trunk. Right behind the seats, near the trunk lid, in the wheel well, or on one of the sides of the trunk in/near the storage cubby.

Behind the seats or near the trunk lid, you have the option of facing it forward or back. If running a single sub you can choose to place the sub to the right, center, or left. Even face it to the left or right. There is also the option of sealed, ported, or even infinite baflle. I've often found that a sub sounds best in the right side cubby and can be hidden pretty well.

Infinite baffle would likely be the most impressive bass setup you'll ever hear... so long as you're not chasing 150db or something. Here's some video of different installs. Rewind to the beginning to get an idea of what is involved with something like this if you're curious. PS Sound is a good resource for a variety of SQ install information as well.

Subwoofer EQ
*About those asterisks in the short list under required parts... Remember those frequency plots above? Yeah, you really don't want the bass to have a massive peak at 60Hz and roll off at 15db - 20db lower at 20Hz. Leaving this as-is will function but be restricted in the low end and most certainly sound “boomy”.

Just as important, the all pass filter at 80Hz will completely remove 80Hz from the sub and much of the content between 70-90Hz when both left and right channel are used.

An easy solution to this, the Kicker KEYLOC, is discussed in the section above.

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Discussion Starter · #8 · (Edited)

Rear Door Speakers

This is the easiest of the OEM speaker upgrades as the options are simple. Replacing these with another standard driver (without a tweeter) may sound a little better, but probably not much. Replacing them with a good coaxial driver will improve sound for everyone in the car.

Front Door Speakers
This is trickier as they are meant to complement the tweeters. In a setup like this, the doors would play below a certain frequency and the tweeters play above a certain frequency. Normally for drivers of this size, the door speakers would play something like 40Hz - 2.5kHz and the tweeters would play 2.5kHz on up. Currently the factory door speakers are wired to play full range (but can't, see specs post) and the tweeter plays 8kHz on up.

If you replace the door speakers with coaxial drivers, the tweeters and the front doors will now both be playing high frequencies and the sound will likely not be great. It will be louder, for sure, but it may be really in your face due to all the treble. Some of it may cancel out or the sound may appear to come from down low or something else you wouldn't expect.

If you replace them with better, non-coaxial drivers, they may not sound as good as the OEM speakers because "normal" 6.5" drivers are not designed to play up to 8kHz. The physical size alone prevents them from sounding as good in a car because you're so far off-axis... the driver side speaker fires directly into your leg! A 6.5" starts beaming at around 1kHz but is typically acceptable until around 2-3kHz. Here's a video on beaming and on/off axis if you're interested.

If you're able to replace the tweeters (next section), I'd go with a component set which consists of a 6.5" driver, 1" tweeter (thereabouts), and a crossover. This way the doors and tweeters are playing what they should be. If you have a DSP and multiple channels of amplification you can customize everything as you please. You don't even need an external crossover.

Door Speaker Installation
Wire harness adapters are available so you don't have to cut your factory door wires. You can also buy 6.5" door brackets, but none of these types of door mounting adapters are great quality and space the driver pretty far back from the door panel. That said, if you're not an audio nut like me, you may like them just fine! The harnesses and brackets are the same for all four doors.

If you want the best sound, build some spacers from HDPE, acrylic, or PVC. They are dense which will remove some unwanted vibrations. You also have the ability to make them as tall as you like to get the driver closer to the door (measure measure measure). They're not terribly expensive to make if you have access to the plastic nearby and have a jigsaw or know someone with a CNC. I paid a local shop $40 to CNC the HDPE plastic I had but it's pretty easy to work with. Including plastic, it cost me about $90 for all four doors.

Here's the end result in my car. I made mine of two pieces as I didn't have one thick piece of HDPE. That would've been ideal. You can also see some sound deadening on the inner door.


Here's a view of the side and back. I used some foam pods I had laying around to keep the water off of the driver. I was surprised there was essentially no protection from rain running down the inside to the door speakers.


Sound Deadening

Optional, but it definitely improved my bass and made the doors "thunk" like my old VW when you shut them. I added sound deadening to the outer door skin and the plastic on the inner door and door panel to weigh it down a bit. It was very boomy around 60-70Hz and was pretty annoying. Sound has been greatly improved. There are many brands to choose from but I had some KnuConceptz deadener from a previous install and bought some thinner black Noico for the door cards/panels as the KnuConceptz was kind of thick and hard to contour for this area. You only need 25-50% coverage in most cases.

Here's the inside of the door panel:


And a peek inside the door, not much to see :) I had my arm all torn up getting it in there as i didn't want to remove the inner panel.


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Discussion Starter · #9 · (Edited)

The tweeters were quite the challenge. The OEM tweeters are 1" but are difficult to replace due to the way they mount. The tweeter itself has a very specific mounting clip on the grille. You can remove the tweeter from the grille by gently prying it out of each clip with a flat head screw driver.

Finger Automotive tire Camera lens Camera accessory Film camera

The outside diameter of the OEM tweeter removed from the grille is about 40mm. Space is very limited and fitting replacement tweeters will be difficult to source. When you remove the grille/tweeter you'll notice how little room you have to even get it out of the dash. Lots of constraints here.

The easiest route

If you don't mind your aftermarket tweeters being visible the upgrade can be fairly simple. Cut a hole in the factory tweeter grilles and flush mount them. Note: flush mounted tweeters firing into the windshield can sound a bit harsh, but not always. You'll want to test the location before committing to flush mount. Angling them a bit, when possible, can help too. You could potentially surface mount, but there's no a lot of room up there. Other options include mounting in pods or on the pillars (careful with airbags). These are often the best sounding positions for tweeters.

My tweeters... not the easy route

Since I already had tweeters and didn't want them to be visible I had to get crafty. I prefer things to look factory to keep the thieves away. Keeping the factory look greatly restricts mounting options.

Inspecting below the grille quickly revealed there would be no easy path. Under the grille/tweeter is just a hole with no mounting flange. The only thing that can be attached to is a bolt near the windshield through the dashboard (circled in green).

Hood Electronic instrument Automotive design Automotive lighting Grille

My Hertz tweeters are much larger at 54mm outside diameter (~40mm OEM) and were on the very edge of being too large.

Watch Automotive lighting Automotive tire Grey Clock

If you replace tweeters, know that this is the upper diameter of what can fit. Here it is face down over the OEM hole which required quite a bit of cutting. Sorry for the glare, I ran out of hands.

Font Camera accessory Audio equipment Automotive wheel system Circle

Making room

I dremeled the plastic clips from the grilles with a dremel as they will only be used as covers in my install.

Gadget Crankset Computer hardware Electronic component Wrist

Next, I removed a fair amount plastic from the opening so my larger tweeter would fit through the hole. Be very careful here since you're so close to the windshield. I didn't take a picture of the hole being cut but you'll see the result it in the gallery up next.

Creating a bracket

I then made custom brackets out of steel sheet from Lowe's that is held in place by bolts in the dash. This took several attempts to get it just right for my tweeter. If you go this route you may need to make the "23mm" tall section longer or shorter depending on the depth of your tweeter.

Gesture Font Art Wood Tints and shades
Wood Art Table Font Flooring
Automotive lighting Automotive tire Hood Automotive design Motor vehicle

The end result, sans grille

Hood Automotive lighting Grille Carbon Automotive design
Hood Motor vehicle Automotive tire Automotive lighting Automotive design

The tweeter is affixed to the bracket by the screw in the back, but 3M tape/velcro should hold perfectly as well for tweeter without this option.

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Discussion Starter · #10 · (Edited)

Obviously, this bit is optional. I generally setup the stereo just for me. When someone else is in the car though, I change my DSP config so it sounds ok for everyone. Adding a center channel can help bring the voices and other prominent centered instruments more centered on the dash.

  • Cut existing fake center cover OR replace with an EX Bose system center channel grille: Kia PN 84715-L3100WK
  • DSP to combine channels, adjust levels, create active crossover, adjust EQ, and remove all pass filters.
  • Run speaker wire from DSP/amp to speaker location 16-18 gauge is sufficient.

Panel removal:

There is a center channel in the EX with Bose, but not the GT-Line. There is a faux grille there though. If you pop that sucker off, there is a cutout for a roughly 4” speaker. I found it easiest to start on the left side behind the headunit.

You can see there are many clips to pop off of this and they really hold well! I swore I was going to break something removing this.


A 3.5-4” coaxial would be perfect if you can find one that fits. I couldn’t find a coax I was willing to pay $$$ for and went with a “full range” Scanspeak 10f as I use them in some computer speakers I built and they sound really good with some EQ. It definitely would be better with a tweeter, but most people should be satisfied with the 10f.

Test fitting the center
It popped right in! the mounting and outer diameters are perfect. Also, with the tiny magnet on the back I didn't have to worry about anything being in the way. I did plug the holes that weren't used by clips to increase the lower end a little bit. This particular driver is useful down to about 250Hz. The lower you can get the better for male voices. unfortunately I didn't get many more pictures, sorry about that.


Bose Grille
As mentioned above, I prefer the stock appearance whenever possible. i replaced the grille with one from the Bose system.


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Discussion Starter · #11 · (Edited)

For those of you who go the DSP route, here are some basic settings to get you started. These are not exact as every system will be a little different but should provide a great starting point.

The following base configuration assumes you replace the factory speakers and maintain the OEM positions, sizes, and proximity to the back of the door speaker grilles.

Time alignment

Some DSPs use delay in ms and others use distance. Some offer both. I find distance easier to wrap my head around and prefer to set it up this way then adjust by ear. These numbers are rounded for readability.

Front left tweeter: 43" / 109cm
Front right tweeter: 58" / 147cm

Front left door: 41" / 104cm
Front right door: 57" / 145cm

Rear left door: 29" / 74cm
Rear right tweeter: 52" / 132cm

Subwoofer: 80" / 200cm

Center channel: 45" / 115cm

Note on Phone calls/Navigation: Kia implemented time alignment for the driver during phone calls and other spoken things. When you add time alignment via DSP so music sounds correct, phone call audio is now diffused. I have not found a workaround but it's a minor inconvenience for me given the benefits.


I typically use 24db/octave Linkwitz Riley for all crossovers becuase it's easy. For the tweeters to mid crossover of 2500Hz this is only a recommendation for a standard 1" tweeter. You NEED to adjust the tweeter high pass and the door low pass to match your tweeter's recommended crossover point as provided by the manufacturer.

Front left tweeter
Low pass: n/a
High Pass: 2500Hz

Front right tweeter
Low pass: n/a
High Pass: 2500Hz

Front left door
Low pass: 2500Hz
High Pass: 80Hz

Front right door
Low pass: 2500Hz
High Pass: 80Hz

Rear left door
Low pass: n/a
High Pass: 80Hz

Rear right tweeter
Low pass: n/a
High Pass: 80Hz

Low pass: 80Hz
High Pass: 20Hz (subsonic filter)
The sub will almost certainly need adjustment in delay and/or phase to match the doors. You could also lower the crossover to 60Hz to avoid some potential cancellation.

Center channel
Low pass: n/a
High Pass: 300Hz (this is what I used for my 10f, this may need to change depending on the driver you use)

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Discussion Starter · #13 · (Edited)

I have intentionally not made any suggestions on speakers as everyone's goals will be different. My system sounds very good but it is also on the more extreme side. I honestly can't make suggestions for speakers I have not heard in this vehicle as they will all fit and sound different. One persons boomy, floppy bass is another's preference ... though I suspect that's mostly because they haven't heard a properly tuned stereo system in or out of the car before.

I have no complaints with my equipment, though I wish I had found a more affordable 4" coaxial for the center channel that met all the constraints. While I didn't want to recommend any specific equipment, if you are comfortable with tuning or are willing to learn a LOT.. the Helix DSP v Eight is absolutely fantastic.

For the curious, my components are as follows:

Helix DSP v Eight - under passenger seat
Mosconi Pro 1|10 - also under passenger seat


Very tight squeeze, but it all fit! These are all class D, sip power compared to A/B amps of similar power and most importantly for me we super compact. They capable of over 2000 watts but I'll never use all that :D

Tweeters - Hertz ML 280.3
Front Doors - Herts ML 1650.3
Rear Door - Hertz MPX 165.3 Pro coaxials
Center channel - Scanspeak 10f/8414g - powered by DSP v Eight

Subwoofer (for now)
Scan speak 30w/4558t - the price has really shot up for this over the past six months. I purchased it for about $200
I haven't built a new cabinet yet as I’m debating whether I want to stick with the 12" or go with a 15" IB.

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2021 K5 GT-Line Wolf Grey
98 Posts
Outstanding work and much appreciated. I used to be really into designing and installing systems for myself and a lot of friends back in my college days but that was 25 years ago and ALOT has changed obviously. Free time is at a premium now so it’s easier to pay to have it done. Lol. I do miss digging into it tho. One question, any idea on the sensitivity levels on the stock 6.5’s?

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105 Posts
Discussion Starter · #15 ·
Outstanding work and much appreciated. I used to be really into designing and installing systems for myself and a lot of friends back in my college days but that was 25 years ago and ALOT has changed obviously. Free time is at a premium now so it’s easier to pay to have it done. Lol. I do miss digging into it tho. One question, any idea on the sensitivity levels on the stock 6.5’s?
Haha, yeah I’ve been collecting this info for a couple months and couldn’t sleep last night so I started to put it together.

I don’t have the setup to accurately test the OEM speaker sensitivity but I’d guess upper 80s.

· Registered
2022 K5 GTLine AWD
57 Posts
This is the best and most comprehensive guide I have ever seen. I'm just looking to balance the sound out a bit and bring back some of the lows.. so I'm looking forward to the info on allpass filters but I also can't wait to read what's next.... keep up the awesome work! :)
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