Adding a subwoofer, in a very different way - Kia Niro Forum
 3Likes
Reply
 
LinkBack Thread Tools
post #1 of 54 (permalink) Old 01-26-2019, 11:42 AM Thread Starter
Member
 
91cavgt's Avatar
 
Join Date: Jan 2019
Posts: 90
Adding a subwoofer, in a very different way

So this post will be my build log for adding a subwoofer amplifier as well as a subwoofer to my Kia Niro LX hybrid.


My primary goal is to add a subwoofer to the stock stereo. However, I have a few requirements that are going to make this build different.

Requirement #1

The subwoofer MUST NOT take away ANY cargo space.


Requirement #2

The amplifier MUST NOT exceed 315 watts which is equal to the Harmon Kardon premium audio amplifier size.


Requirement or Preference #3

A 10” subwoofer is used.



So how in the world am I going to have a 10” subwoofer not take up any cargo area? Well, I could put it in the spare tire well, but then I would have to put my spare tire and/or the tire tools in the cargo area. So that place is out. After looking and measuring closely, it looks like I can build a custom subwoofer box for a 10” sub to go UNDER the driver seat! Yes, that’s right. A 10” subwoofer under the driver seat.

Since my LX model does not have power seats, there is 6” of height there. Front to back is about 10” and width under the seat rails is a whopping 20”!! So that will leave me with a box of only, about 0.35 cubic feet. That’s not much to work with, but I found a shallow mount 10” sub that has a minimum sealed air space requirement of 0.35 cubic feet. Perfect!

The amp I will be getting has the capability of putting out nearly 700 watts so I’ll have to put my meter on it and turn the gain down so the maximum RMS wattage will be 300 watts, which is more than enough to drive this particular sub.


But before I order the sub online, I want to build the box. After the box is built I will be able to accurately measure the air space and will then confirm that this sub will work. If the box ends up being less air space than what I originally anticipated then I’ll have to downgrade to a single 8” sub that will work in the available air space.


So as progress is made, I will update this thread and will be taking pics along the way.
Dave likes this.
91cavgt is offline  
Sponsored Links
Advertisement
 
post #2 of 54 (permalink) Old 01-26-2019, 11:50 AM Thread Starter
Member
 
91cavgt's Avatar
 
Join Date: Jan 2019
Posts: 90
What about the air vent under the driver and passenger seats that sends air to the back passengers?


In the back seat on the drivers side is my daughters car seat. That car seat is always in place so I can remove that vent.

That’s all fine and dandy, but how do you remove it?

You simply grab it and pull to the back of the car. It will pop out, and can be easily popped back into place at a later date if needed. Attached is a picture of the vent that has been removed.
Attached Thumbnails
Click image for larger version

Name:	image_1548521371704.jpg
Views:	178
Size:	114.8 KB
ID:	4447  
91cavgt is offline  
post #3 of 54 (permalink) Old 01-26-2019, 12:01 PM Thread Starter
Member
 
91cavgt's Avatar
 
Join Date: Jan 2019
Posts: 90
So why only 300 watts?


I wanted to have more power but I was unsure of the capability of the factory DC-DC converter. After numerous phone calls and a few online searches I could not find the rating.

So what I did is I looked at the factory premium audio amplifier and it’s ratings. There is a fuse under the dash for that amplifier and it is a 30 amp fuse. Attached is a picture of where that 30 amp fuse is located.

With that fuse removed, the factory radio still works. So, only the premium audio systems use that fuse. A simple, and typically pretty accurate, way of determining a Class D car audio amplifiers maximum RMS wattage is multiplying the fuse size times 10 (10 represents the voltage used which is higher but no car audio amp is 100% efficienct. So multiplying the fuse size by 10 gives you a more accurate wattage rating instead of multiplying fuse size by 13 or 14.). So this limits maximum amperage to 30 amps and maximum wattage to 300.


I want to stay within the factory wattage so as to be 100% sure that I will not be causing other problems due to excessive power consumption. This way, if there ever is an electrical problem in the car, it helps to minimize the possibility the warranty will be voided.
Attached Thumbnails
Click image for larger version

Name:	image_1548522097298.jpg
Views:	103
Size:	133.1 KB
ID:	4449  
91cavgt is offline  
post #4 of 54 (permalink) Old 01-26-2019, 12:48 PM
Senior Member
 
Join Date: Sep 2018
Location: California
Posts: 249
Garage
You should end up with a good flat bass curve with the setup you've got planned. Probably wont get as much in the 20-40hz (really deep bass) range due to the starved enclosure volume, but you'll still get some bass in that range, and 40-100hz ought to be pretty good, and definitely should keep up with the factory speakers.

I'm not a fan of boomy bass, and I like bass that is the same level as the mids and highs. In other words, I like my "curve" to be flat. I don't like bass that's louder than what the recording meant for it to be. So I think your setup is going to get you as close to that goal as you can possibly get without sacrificing cargo space. What subwoofer did you pick?

2018 PHEV
cockedandglocked is offline  
post #5 of 54 (permalink) Old 01-26-2019, 09:02 PM Thread Starter
Member
 
91cavgt's Avatar
 
Join Date: Jan 2019
Posts: 90
Exactly. It should be a decent sound quality setup vs an spl setup. The system in my last car was over the top and was metered at 137.6 dB at 80% of the tuned volume and was loud enough to crack the windshield in half. I’ll attach a picture of the crack on the windshield and how far the crack would progress each day that I cranked the volume. It was nice on occasion but I rarely cranked it that loud, so this time I’m going back to a modest system.


I narrowed a list of possible subwoofers down to 10. From there I kept narrowing the field until there was only one clear option. They ranged in price from $50 all the way to $200. I took a lot of notes and compared their sensitivity, minimum sealed enclosure volume, Xmax, voice coil size, and bl specifications. Shockingly, in the end the $50 subwoofer had a better overall fit for what I was looking for. That subwoofer is a Cadence SLW10S2 which is a shallow mount 2 ohm 10” sub. I wanted a JL Audio sub, but the only one they had that was going to be anywhere close to meeting my needs was going to run over $300, and with the rest of the system being stock I just could not justify that.



This is not my first attempt at an under seat subwoofer. I had a 2014 Mitsubishi Mirage that I made a custom sealed enclosure for under the passenger seat. It was only 0.25 cubic foot and had an MB Quart 8” powered by a 250 watt JL Audio monoblock subwoofer amp. It sounded very good and despite the small box it had really good low end. Primarily because a sealed box has a smoother roll off on the bottom end over any other kind of box(except for a transmission line) and the amp was pushing 200 watts rms to that little 8”.
Attached Thumbnails
Click image for larger version

Name:	E82B26B6-6E99-4C37-80CA-D98278D57985_1548554534298.jpeg
Views:	158
Size:	431.9 KB
ID:	4455  
91cavgt is offline  
post #6 of 54 (permalink) Old 01-28-2019, 12:25 PM Thread Starter
Member
 
91cavgt's Avatar
 
Join Date: Jan 2019
Posts: 90
After leaving work this morning I stopped by a local home improvement store and picked up a few things so the build can start soon. Picked up a single sheet of 3/4”X2’X4’ MDF, 2 cans of black spray paint, some new sanding pads for my sander, some wood putty, and a little wood glue.

I should be able to get started on the box next week. This week I’m too busy today and tomorrow, then my wife is taking my Niro out of town for work from Wednesday through Friday, then late Friday we are heading out of town all weekend for my daughters birthday party. So hopefully the weather will cooperate next week.
Attached Thumbnails
Click image for larger version

Name:	4A83185D-2318-4A5C-BD73-4722A299CD89_1548696305935.jpg
Views:	87
Size:	190.3 KB
ID:	4457  
91cavgt is offline  
post #7 of 54 (permalink) Old 01-29-2019, 10:50 AM
Member
 
Join Date: Sep 2018
Location: Colorado
Posts: 31
Not to downplay the awesomeness of OP building his own custom box, but wouldn't a couple pre-fabbed units under both seats bump louder and with less effort and even less cost?

https://www.ebay.com/itm/Crunch-8-In...-/352475746704


I've used under-seat subs before, and they work well for filling out the low-end. Further, having two would prevent the bass from feeling like it's coming from one place (under just your seat) and keep it more omni-directional. There are dozens of other options/brands that would fit as well. Eg, I like how the Pioneer TS-WX130DA has a multi-option remote, rather than just gain. There are others with similar multi-option remotes as well.

2018 Niro LX PHEV
2019 Pacifica PHEV
dots is offline  
post #8 of 54 (permalink) Old 01-29-2019, 10:59 AM
Senior Member
 
Join Date: Sep 2018
Location: California
Posts: 249
Garage
Those pre-fab boxes will sound worse. Probably much worse. OP is making his box with 3/4" mdf, the prefab box is probably plastic or sheet metal, which causes distorted, muddy bass because most of the output will be coming from enclosure flex/vibration rather than from the cone. Also it's only an 8" sub in your example, so it won't produce much low-bass, regardless of what the mfgr specs say (as an engineer in the speaker manufacturing industry, I can attest that 99% of manufacturer claims are usually unrealistic at best, or downright lies at worst). For low bass, you need a bigger cone, it's physics. A pre-fab sub is better than nothing, but since OP can make his own, he made the right decision.

2018 PHEV

Last edited by cockedandglocked; 01-29-2019 at 11:05 AM.
cockedandglocked is offline  
post #9 of 54 (permalink) Old 01-29-2019, 03:22 PM Thread Starter
Member
 
91cavgt's Avatar
 
Join Date: Jan 2019
Posts: 90
Not to mention a very large majority of those pre-fabbed setups have VERY poor amplification. Most of them claim 200-500 watts, but they only have a 5 amp fuse! Take the fuse rating and multiply that by 10 and that will be a realistic amount of power that it would make.


Yes, I did spend some time researching them. Since I know how to properly build a box and do all of the wiring myself, the cost is very close between a pre-fabbed box/amp/sub and me putting everything together. As of right now, the total cost will be less than $200 for everything.

As to directional sound from the sub, the only time that becomes a factor is with midbass frequencies. Hearing where the sub is at is typically caused from poor crossover frequency selection which most of the time is due to a lack of midbass response from the other speakers. With how well the stock speakers produce midbass in the Niro, that will allow a lower crossover frequency to be used which will reduce or eliminate the directional sound coming from the subwoofer.


Having been in car audio since the early 90’s, I have seen many new technologies come about which have helped to improve the performance of car audio. One of the best increases in technology has come by the means of better subwoofers. In 1995, Alma Gates held the world record for the loudest car audio system in the world. It was a little over 153 dB. Fast forward 20 years and you can now have this same volume in a vehicle that you drive everyday. Another big gain has come from required enclosure size. In the early 90’s it was common for a 12” sub to require a 2 cubic foot sealed box. Then Kicker came along with their Solobaric line and dropped that requirement in half. Short of an isobaric setup(which is where the Solobaric sub got its name) there was no other way to get good bass from a small enclosure. So here we are today and I am looking at spending merely $50 for a 10” sub that will work in a 0.35 cubic foot sealed box. That just blows my mind!!
Dave likes this.
91cavgt is offline  
post #10 of 54 (permalink) Old 01-29-2019, 03:41 PM
Senior Member
 
Join Date: Sep 2018
Location: California
Posts: 249
Garage
I'm also glad that people have started to realize that ported boxes are awful.

When I was in high school, they were all the rage, because they made your bass go boom. The only problem is the bass only went boom in a very narrow bandwidth (say 70-80hz), but at other frequencies the bass was almost non-existant because of 1) a complete lack of air suspension and 2) the bass coming out the port was invariably out-of-phase with (and thus cancelling out) the bass coming from the cone. The result was bass that was only audible in one or two very specific and very small low-frequency bandwidths, so it only sounded good when playing a song that had a bass track that happened to coincide with that bandwidth. In other words, they sounded really impressive as long as you only ever played one specific track on one specific cd
Dave likes this.

2018 PHEV

Last edited by cockedandglocked; 01-29-2019 at 03:45 PM.
cockedandglocked is offline  
Reply

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Forum Replies Last Post
Adding subwoofer jaxterra Electronics, Audio, and Lighting 17 03-30-2019 11:10 AM
Installed a small subwoofer hackenfort Electronics, Audio, and Lighting 19 03-24-2019 12:05 AM
Subwoofer in 2019 LX chad Electronics, Audio, and Lighting 1 01-12-2019 03:25 PM
Adding Autonomous Emergency Braking AFTER sale??? eddarrah Kia Niro General Discussion 0 09-02-2017 12:59 AM

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome