Subwoofer Install w/ Harman Kardon System

[WildBill]

Yes you are correct. I initially tapped the front door speakers thinking that they were full range. They are not. They have a high pass filter applied. The subs obviously have a low pass filter which you would have no adjustment over.
There are devices that can combine the signal from multiple high level inputs to create full range, which you can later break back down as you wish. Again, too complicated and expensive for me.

 

[itguy61]

Where in the rear is the stock HK amp? Is it under the floor or behind one side trim panels?


Thanks!

 

[AV8R]

RHS panel in trunk

 

[itguy61]

RHS panel in trunk

Thanks so much!

 

[AV8R]

Do you want schematic?

 

[AV8R]

 

[Joe Kraebel]

I got the upgrade itch to move to a 12" and built a new box for a JL 12TW3-D4. Props to Mark at Car Audio Fabrications YouTube channel for ideas: CarAudioFabrication




I have also finally tapped into the sub outputs from the amp and definitely getting a lot more on the low end. This does have a trade-off however as the sub outputs are crossed over too low and seems like they cutoff most over 50HZ which loses a lot of bass in the 50-80HZ range that the rest of the speakers just can't fill.

I picked up an LC7i because it does input summing as I figured I can run both the front door out and sub out to the LC7i, sum the signal and send to the sub amp using its crossover to cut off anything over 80hz or so however I don't think this sends the summed output to channel 3 which is the only channel that you can use the accubass and remote knob on so might be sending it back.

Does anyone have any experience with the LC7i?

 

[MrSmoofy]

I got the upgrade itch to move to a 12" and built a new box for a JL 12TW3-D4. Props to Mark at Car Audio Fabrications YouTube channel for ideas: CarAudioFabrication

View attachment 47128View attachment 47129View attachment 47130View attachment 47131


I have also finally tapped into the sub outputs from the amp and definitely getting a lot more on the low end. This does have a trade-off however as the sub outputs are crossed over too low and seems like they cutoff most over 50HZ which loses a lot of bass in the 50-80HZ range that the rest of the speakers just can't fill.

I picked up an LC7i because it does input summing as I figured I can run both the front door out and sub out to the LC7i, sum the signal and send to the sub amp using its crossover to cut off anything over 80hz or so however I don't think this sends the summed output to channel 3 which is the only channel that you can use the accubass and remote knob on so might be sending it back.

Does anyone have any experience with the LC7i?

WOW That's a really nice looking box

 

[andrew tay]

I got the upgrade itch to move to a 12" and built a new box for a JL 12TW3-D4. Props to Mark at Car Audio Fabrications YouTube channel for ideas: CarAudioFabrication

View attachment 47128View attachment 47129View attachment 47130View attachment 47131


I have also finally tapped into the sub outputs from the amp and definitely getting a lot more on the low end. This does have a trade-off however as the sub outputs are crossed over too low and seems like they cutoff most over 50HZ which loses a lot of bass in the 50-80HZ range that the rest of the speakers just can't fill.

I picked up an LC7i because it does input summing as I figured I can run both the front door out and sub out to the LC7i, sum the signal and send to the sub amp using its crossover to cut off anything over 80hz or so however I don't think this sends the summed output to channel 3 which is the only channel that you can use the accubass and remote knob on so might be sending it back.

Does anyone have any experience with the LC7i?

I used lc7i. Its pretty good. I used it to power the amps which does not have high level input, for the door woofers and middle channel.. IMO they are better than most high level inputs built into amps.

 

[Joe Kraebel]

Do you know if there is any way to sum any of the inputs to the Channel 3 output? I was thinking of trying front doors to input 1 and subs to input 2 with the auto mode engaged to send to output 3 but I think that would only send output 2's signal and not both summed. It also seems like the summing only sends the summed signal to output 1 which I don't want to use as I would lose the accubase and remote functions.

My issue is that it is severely lacking in the 50-80hz range only using the sub out on factory amp and using front door out loses a lot of the low end so looking for a processor that can sum both of these channels and send it to sub amp, then use the low pass filter at 80hz or so.

 

[WildBill]

My issue is that it is severely lacking in the 50-80hz range only using the sub out on factory amp and using front door out loses a lot of the low end so looking for a processor that can sum both of these channels and send it to sub amp, then use the low pass filter at 80hz or so.

I 100% agree and would love to see a solution too.

 

[andrew tay]

That's strange that you lack frequency under 80 hz on factory sub out. I got too much low frequency from factory sub out and need to turn down the bass on tone control. I use factory sub to channel 2 in and channel 2 out to sub amp without summing and accubass set to zero.
Could you have connected the input in reverse? Check your polarity of the speaker input to make sure that they are connected in phase. Then just change polarity of the front door channels one of the time and check the bass output using your phone. I have discovered that one of the frond door channel has been connected in reverse phase from factory which could have lead to bass cancellation during summing process

 

[andrew tay]

xx

 

[Joe Kraebel]

That's strange that you lack frequency under 80 hz on factory sub out. I got too much low frequency from factory sub out and need to turn down the bass on tone control. I use factory sub to channel 2 in and channel 2 out to sub amp without summing and accubass set to zero.
Could you have connected the input in reverse? Check your polarity of the speaker input to make sure that they are connected in phase. Then just change polarity of the front door channels one of the time and check the bass output using your phone. I have discovered that one of the frond door channel has been connected in reverse phase from factory which could have lead to bass cancellation during summing process

Actually I never thought of the polarity and is something I will check after I run some tests with my laptop and REW (Room EQ Wizard).

I do think it is improved however as when I went to set the gain on the amp to the proper level I noticed the low pass filter seemed to be set a little low so I bumped it up to 80hz.

Have you ever hooked the sub out to an RTA or an oscilloscope to see what frequency range it is actually outputting? Also, being that you have Accubass turned all the way down would you say there is not any roll-off from the factory system or could it be since you are using aftermarket speakers and amps that you don't need to turn the volume up high enough to experience that?

 

[andrew tay]

Actually I never thought of the polarity and is something I will check after I run some tests with my laptop and REW (Room EQ Wizard).

I do think it is improved however as when I went to set the gain on the amp to the proper level I noticed the low pass filter seemed to be set a little low so I bumped it up to 80hz.

Have you ever hooked the sub out to an RTA or an oscilloscope to see what frequency range it is actually outputting? Also, being that you have Accubass turned all the way down would you say there is not any roll-off from the factory system or could it be since you are using aftermarket speakers and amps that you don't need to turn the volume up high enough to experience that?

I dont have a osciloscope LOL. The bass channel cut quite high, 200hz maybe. Instead of roll off, its bass bump up quite a bit. I would guess around +10db at around 40 Hz based on crude measurements with Samsung phone. I tune the volume to around 95db at level 25. Could have a little roll off but its good because at lower volume its just have too much bass.

 

[ST1276]

Jumping in at the end of this thread. But I just tested all my speakers. I have the HK amp setup. ALL speakers except the center channel are out of phase. Used a polarity checker from Amazon and the test tone. I am starting to plan my door speakers upgrade with a 4ch amp. I already have the sub and sub amp running with a passive LOC. I think I can use the LC7i and take the rear door and subwoofer. That should give me the full signal for the LC7i to sum and give me F,R, and sub output. I plan to keep the center channel running off the factory HK amp. Any thoughts of someone that has added more than just a sub amp would be appreciated. I will confirm this weekend that the rear tweeter, midrange, and midbass are all on the same channel. Thanks all!

 

[andrew tay]

Jumping in at the end of this thread. But I just tested all my speakers. I have the HK amp setup. ALL speakers except the center channel are out of phase. Used a polarity checker from Amazon and the test tone. I am starting to plan my door speakers upgrade with a 4ch amp. I already have the sub and sub amp running with a passive LOC. I think I can use the LC7i and take the rear door and subwoofer. That should give me the full signal for the LC7i to sum and give me F,R, and sub output. I plan to keep the center channel running off the factory HK amp. Any thoughts of someone that has added more than just a sub amp would be appreciated. I will confirm this weekend that the rear tweeter, midrange, and midbass are all on the same channel. Thanks all!

Check my post:

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Change Harman Kardon speakers Kia Stinger

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[andrew tay]

Change Harman Kardon midrange speakers Kia Stinger

Been testing the door speakers. I have changed the woofers in the car door. Some improvement but not as much as I hoped for. Tested the door speakers and realised that the mids are the weakest link. The ones at the door are 2 ohm 2.5 inch and the centre one is 4inch. The 2 inch tweeters are...

stingerforum.org

Jumping in at the end of this thread. But I just tested all my speakers. I have the HK amp setup. ALL speakers except the center channel are out of phase. Used a polarity checker from Amazon and the test tone. I am starting to plan my door speakers upgrade with a 4ch amp. I already have the sub and sub amp running with a passive LOC. I think I can use the LC7i and take the rear door and subwoofer. That should give me the full signal for the LC7i to sum and give me F,R, and sub output. I plan to keep the center channel running off the factory HK amp. Any thoughts of someone that has added more than just a sub amp would be appreciated. I will confirm this weekend that the rear tweeter, midrange, and midbass are all on the same channel. Thanks all!

 

[andrew tay]

I have since changed the middle channel to 4 inch JL audio speaker. A little improvement in vocals.

 

[RogueIV]

@ST1276 If all of your speakers are out of phase except one it sounds more like one is out of phase and the rest are fine. What matters most is that everything is in phase with each other.