Impala Forums banner

1 - 9 of 9 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
After finding a dearth of useful information about improving the mediocre sound system in non-Bose equipped Impalas (RPO IO5) I thought I would post my successful stereo upgrade experience in my 2019 Impala for everyone's benefit. From scouring the internet and my own testing I discovered the following characteristics about our Impalas :
  • the first problem was the head unit - difficult to replace due to its integration into so many control aspects of the 9th gen. Impala with limited and expensive replacement options.
  • the second problem was that the head unit doesn’t send a conventional audio signal to the speakers - it sends a digital signal to a processor/amplifier in the trunk which then sends a narrow spectrum audio signal to the various speakers - upper range to the dash tweeters, bass signal to the front door speakers, midrange to the rear door speakers.
My solution was to continue using the OEM head unit/amp combo and get a 4 channel amplifier (Kenwood KAC M3004) that was able to accept speaker-level inputs and a pair of coaxial 6 x 9" speakers (Infinity Reference REF 9632ix) for the rear deck.
Trunk mounting the amplifier was the logical solution since the speakers were mounted there and the audio signal from the OEM amplifier was accessible. I used a good automotive adhesive to attach a 1/2" piece of plywood to the right rear wheel well and then screwed the amp to it.
Power for the amp was routed under the rear seat, through the center console and through the large rubber grommet/membrane on the driver's side firewall. Piercing it with an awl of sufficient diameter created a nice tight hole for the power wire and as the battery is on that side it was very convenient for connection. The positive battery connection terminal box had an extra empty terminal post tailor-made for the purpose.
Behind the OEM amplifier mounted near the right rear wheel well was a convenient ground connection.
I tapped into the speaker wires from the OEM amp for the speaker-level inputs for the Kenwood - front dash speaker wires into channel A for the rear tweeters (LF+ yellow/blue, LF- yellow/gray, RF+ brown/green, RF- violet/brown) and front door speaker wires into channel B for the rear woofers (LF+ blue, LF- brown/blue, RF+ yellow, RF- yellow/ black). And yes, before I get any flak for this I'll explain my guerrilla install. I purchased coaxial speakers for their compactness in the mounted location but I desoldered/disconnected the woofer wires from the speaker wiring post, soldered them to another binding post I had from another old OEM speaker and connected channel B to that, essentially creating a component speaker system.
A component speaker might be the best option for those squeamish at the thought of modifying their newly purchased coaxial speakers, but it worked out for me. The rear deck fabric surface is approximately 40 mm from the steel deck framework so there was pleny of room to build up a speaker mount from plywood to mount the speakers to the deck frame.
The only thing left to do was to adjust the gains of both channels on the Kenwood to achieve a balanced sound front to rear, treble to bass, fader on the head unit set towards the front to minimize the bland contribution of the rear door speakers. The resulting sound, while not state-of-the-art is quite satisfying with the OEM speakers not sounding too bad having the better Infinitys prop them up. A very nice headphone effect that was unfortunately missing from the original setup. Bass is adequate and accurate. Subwoofer hounds will find it lacking but it still is very musical.
162738
162739
162740
162741
162742
162743
 

·
Registered
Joined
·
2,876 Posts
My solution was to continue using the OEM head unit/amp combo and get a 4 channel amplifier (Kenwood KAC M3004) that was able to accept speaker-level inputs ...
Kudos on that. I think way too many people fail to take advantage of the speaker-level inputs and waste money on unnecessary line-out-converters.


I tapped into the speaker wires from the OEM amp for the
speaker-level inputs for the Kenwood - front dash speaker
wires into channel A for the rear tweeters ... and front door
speaker wires into channel B for the rear woofers...
That sounds reasonable, but I'm curious - were there no rear door speakers to tap into?


...soldered them to another binding post I had from another
...old OEM speaker and connected channel B to that, essentially
creating a component speaker system.
I have some Sanyo coax speakers, left over from the late 70's, that came with the separate terminals for the tweeters. Back then, this hookup was called "bi-amp" wherein the head unit sourced separate outputs for tweeter and woofer. And for a head unit without that, the speaker included a jumper with high-pass cap to connect the tweeter and woofer.

Anyway, more kudos for that hack :)

Doug

.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #3
Kudos on that. I think way too many people fail to take advantage of the speaker-level inputs and waste money on unnecessary line-out-converters.




That sounds reasonable, but I'm curious - were there no rear door speakers to tap into?




I have some Sanyo coax speakers, left over from the late 70's, that came with the separate terminals for the tweeters. Back then, this hookup was called "bi-amp" wherein the head unit sourced separate outputs for tweeter and woofer. And for a head unit without that, the speaker included a jumper with high-pass cap to connect the tweeter and woofer.

Anyway, more kudos for that hack :)

Doug

.
Thanks for the kudos, Doug. It's too bad that modern equipment doesn't have more options for alternate wiring. I sense that there are less people willing to experiment these days. Just from my testing I fed test-tone signals into the various speakers and found that the rear door speakers didn't seem to be fed a full spectrum sound signal. Either that, or they are so bad that they are unable to reproduce one so I went with the likeliest path for the best sound.
 

·
Registered
Joined
·
2,876 Posts
Just from my testing I fed test-tone signals into the various speakers and found that the rear door speakers didn't seem to be fed a full spectrum sound signal.
I have a 1975 JCPenney AM-FM radio in my garage I listen to regularly. And, if I'm hooking something up and need a test signal, I use it and a patch cord with alligator clips on one end for doing similar testing.

That said, with all the digital buses in cars these days, such as CAN and the audio link you mentioned, technicians almost need oscilloscopes to trouble shoot problems. In fact, I used on one somebody's ignition coil module recently.

Doug

.
 

·
Registered
Joined
·
14 Posts
Very nice installation.... I did a very similar install in my 2019 impala. Im curious, When adding 6x9s to the rear how did you mount them? I just got some 6x9s and got holes cut out but not mounted yet. There is a gap between rear deck and mounting location so I'm looking for a plan because Im afraid of bowing in rear deck
 

·
Registered
Joined
·
4 Posts
Discussion Starter #6
Very nice installation.... I did a very similar install in my 2019 impala. Im curious, When adding 6x9s to the rear how did you mount them? I just got some 6x9s and got holes cut out but not mounted yet. There is a gap between rear deck and mounting location so I'm looking for a plan because Im afraid of bowing in rear deck
Thanks..... From my measurements there is a 40 mm (1.5 ") gap between the steel rear deck and the cloth trim panel.
This gave me the ability to make a 1.5 " layered and glued plywood adapter that mounted to the top of rear deck and the 6 x 9's were screwed to that. There was enough room to turn the speakers 90 degrees from the OEM orientation to point my tweeters towards the front of the vehicle but that was mostly just my visual preference. The plywood screwed to the steel rear deck with a homemade foam gasket between also solidified it, damping any resonances that may have been present. Seems very sturdy.
 

·
Registered
Joined
·
19 Posts
How did you deal with the anc signal coming out of your amplified speakers. I used an ax dsp most1 from axxess/metra sounds awesome cost was equivalent to a good head unit
 

·
Registered
Joined
·
4 Posts
Discussion Starter #9
My 2019 Impala 1LT has the 3.6l V6 so it doesn't have active noise cancellation, making my install more straightforward.
Thankfully I was able to avoid that upgrade path and use the OEM head unit/amp with better speakers.
I'm glad that you were able to get excellent sound with that unit. From what I gather that unit bypasses the OEM amp and allows you to use your own amplifier, giving you a more direct path to the original signal and presumably better audio with the right components
 
1 - 9 of 9 Posts
Top