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Lithium's 2015 Honda Accord - Active 2/3way+sub

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2015 Honda Accord Coupe (big upgrade from the rusted out Buick)


I think a lot of folks found time in 2020 to get some work done on their builds. I picked up my Accord early in the year after my old Buick Century showed signs of death. You guys might recall my buick build log from 2015-2019, but I went a bit crazy near the end of it with Super huge dash pods and Sls 8 door enclosures.





Well I don't plan to cut up my car that much this time around. My initial plan is a simple active 2 way + sub. I did all this work at my apartment building's parking lot so I tried to keep things manageable this year. After figuring out how the car responds I can plan next steps. 


SSA Evil 6.5" Mids

SSA Evil 1" Tweeters

Fi IB3 15" Infinite baffle sub

Peerless sls 8 - experimental sub/mid bass 

NVX Jad8004 - mid/tweets

Cadence zrs3002 - subwoofer

polk pa d2000.2 - SLS 8s

MiniDSP 6x8

jl audio loc22 (factory integration) 

jl rc-lrc (fancy bass knob for my old cadence amp) 

Fiio e10k (DAC w/ digital output - my phone is the main source off this DAC)

Knukonceptz Kolossus CLD (doors)

Second skin damp pro CLD (left over used on rear deck)

NVX CLD (trunk, trim panels)

Knukonceptz Kolossus  0 gauge kit


A lot of work was done by folks like @keep_hope_alive  to document installations in 9th gen accords. Here is his build, great reference for 9th gen owners. 


Power wire

Starting with the fuse holder. I created an ABS bracket and mounted it off some factory hardware around the airbox. Knukonceptz battery terminal was used here on the positive terminal. 


Power wire is run through a grommet above the kick panel.  There are three grommets here, 1- moon roof drain, 2- hood latch, 3 - empty for my trim package. 




Not pictured - added extra battery negative to ground at factory location. 

Sound Deadening

I established some priorities for applying treatment in this car. The trunk interior was treated with the cheaper NVX CLD due to the use of an IB subwoofer in the ski pass. The trunk treatment of CLD only serves to cut down on rattles outside the car. Everything facing the interior of the car was treated with better materials. 

Some areas in the trunk I removed factory material, primed, and applied deadener. 






Rear deck was treated with second skin damp pro. I sealed off the factory rear speaker holes. I also sealed up openings in the rear quarter panel (where the rear doors would be on a sedan). 


These cavities are open to the trunk so I applied CLD and stuffed the area with denim insulation (KHA style). 







I did not deaden the roof or floor. I might have to address the roof later but pulling the headliner doesn't sound fun... 

On to the front doors! Pulled out all the tricks I knew to get these doors to work and tried out a new technique w/ mineral wool absorption (hopefully sound and not water...)

CLD outer skin, butyl rope between crash bars and door skin. 




Mineral insulation wrapped in thin plastic drop cloth. This shit kinda scares me, drove around for about 1-2 months to see how these deal with rain. 

You can also see riv nuts used seal up the access holes. 


CLD on the inner skin and HDPE mounting ring installed. 


Aaron at SSA signed some of the mids 




applied some CCF around the parameter to prevent buzzes


1/8th inch plastic (extruded PVC or something similar) was used to seal up the holes. I had to deform these with a heat gun to get the door trim back on. The trim panels actually extend pass the exterior mounting on the coupes. The plastic was installed with rivnuts, butyl rope, and duct seal. Duct seal is some great stuff! 


Used up the last of my CLD on the door seals


Silicon baffle things installed on the mids. Thinsulate added to the rear of the door trim. The factory door trims have a good amount installed stock. 


I decided to cut the lip off the factory trim panel and use these silicon baffles to seal the woofer and door. I would have preferred to keep the trim panel stock and use some foam to mate the woofer mounting ring and door trim but I ran into some tolerance issues. I'm not sure if this actually matters. I think I'll take some measurements with the door time off sometime later this year to see what they do. 


Door trims where fully treated overkill style. Removed the foam blocks and added some thinsulate to fill any cavities. 


Repeated on the other side. 


Jumping back to the rear deck I decided to keep the trim panel "floated" and just secure it with the C pillar trims. CLD, CCF, and thinsulate applied. 


Missing photos - C pillars, rear quarter/passenger panels, B pillars were all treated similarly. 

Infinite baffle subwoofer installation

This car does not have a 60/40 rear split seat like most sedans. So I was concerned that I wouldn't be able to run an IB subwoofer. After a convo with @dcfis he informed me that IB works well in the coupe due to a large number of holes in the rear seat back frame. I plan to get some measurements of seat up vs down soon. 



Previously I was using this Mach 5 Audio MJ18 but shoe horning an 18 into a car is pretty hard so I downsized to a beefier 15"  Fi IB3. 


This is my strange looking baffle.. Not sure how this shape happened. I painted the mdf with some bed liner and called it good. No one will see it... 



It mounts off the ski pass braces with some bolts and threaded inserts. Unfortunately, I decided to hack up the carpet here. After I install a beauty panel everything will look great but I ran out of time this year. 


Tweeter Sail Pods

These just fit up to the factory panel without much modification! Looks good but I didn't play around with aiming at all.... 


Factory integration

For those unfamiliar, 9th gen accords with the nav package output a flat signal from the HU. You simply buy a Honda connector and bypass the factory amp. Because the factory signal is balanced I bought a Loc22 to convert to unbalanced for my miniDSP. I think the 8x12 can accept balances so maybe I should have just upgraded DSPs while I was at it. 

Blurry picture of the loc22, Fiio E10k (with power adapter), and my usb's for the DSP tuning installed under the passenger rear seat. 


Temporary Amp Rack

So I'm not sure what my plan is for the system. I figured I would miss running a midrange in the future and I might need to change up the amps. Given this was around October the weather on the weekends was not always great for working on the car so I decided to make a temporary amp rack and get down to some tuning and listening. 

Just dont zoom in too much. First time tech flexer and I picked out some shitty heat shrink. 


I just threw this sucker on top of the spare tire  with the miniDSP positioned just right. 



Stuff not pictured that I will add soon

I have the SLS 8s in .5 cuft enclosures behind the seats in the rear foot wells. Drivers are located on ends of the enclosures and positioned as wide as possible. I'm playing with distributed midbass. But right now they're mostly just extra subs to compensate for another issue with my tune. 

First impressions of the front stage

The SSA drivers are doing really well. I think for a 2 way they sound great. The last time I ran a 2 way was some phoenix gold RSD's from a couple years back (if anyone remembers those). I'm going to continue tuning but I might end up moving towards a new front stage with a midrange. My previous car had mark audio alpair 7s and those were amazing in those giant dash pods. Its a little unfair to compare the SSA set ($50 drivers) vs ($90 midranges) but I also preferred some of the advantages with mounting the mid up high. 

So I think the SSA drivers will go into a home audio project to replace my Hitmaker near field monitors and my front stage will be a 3 way with Anarchy 7s, Fountek FR59EXE 2", and Dayton ND16. The mid and tweet will be installed in small sail panel pods.  I also picked up the Sony XM-GS4 while I was at it. 

I would also like to add that my doors are very robust and rattle free. I haven't had doors hold up this well before. I am crossing the mids at 70 or 80 Hz so that is helping things. Jury is out on the mineral wool, wish I could do some comparison measurements or just listening impressions but that's difficult for me until I have a garage to work out of. 

First impressions of the subwoofer install 

I'm currently have some issues with intergrading the mid and subwoofer. It seems the IB3 is rolling off at 60hz resulting in a null  between 60-80  Hz. After some more reading, I think its just the design of the subwoofer itself that's the issue (more so my application of this subwoofer). I might swap it out with something that can play a bit higher to meet up the 6.5's in the doors. My current band aid is using the SLS 8s as secondary subs and increase/decrease the IB3 level as I like. I think I have a lot more work to do on the subwoofer tune before I give up. But its certainly not as simple as my previous IB installs with the MJ 18 (typically very little eq necessary). 

Amps/DSP Comments

I'm considering upgraded my dsp to the 8x12 w/ Dirac Live. I'm really curious at the technology but I'm not ready to drop a grand right now. Maybe if my job had not cut my 12% yearly bonus due to COVID (despite staying open as an essential business) I would be all over it! 

Edited by lithium

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I'll come back later and update the photos! 

Edited by lithium

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HOLY SHIT! Does the Accord have the 4 or 6 cylinder?

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1 hour ago, Tirefryr said:

HOLY SHIT! Does the Accord have the 4 or 6 cylinder?

Haha! This is the v6 automatic. 

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