2018 Premium Audio System

[SCOPESYS]

Honda 2018 Premium Audio - REVEALED Project

Feb 2019
(Work in Progress) Will take a few days to publish the existing work, and finish setting up these 1st 11 pages

Over time (weeks /months) I will add content for the empty pages, as I get measurement results.

Note: There 1st 11 pages are DYNAMIC, and will be regularly updated.
You might want to review them periodically, if this is a subject that interests you.


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Table of Content (Links)

(1) Sub Speaker Channel

(2) Center Speaker Channel

(3) Front Left & Right Speaker Channel

(4) REAR Left & Right Speaker Channel

(5) TWEETER Speaker Channels

(6) LC2i and Additional Sub Amp

(7) Combined Sub + Center + Tweeters

(8) --------- (to do : Combined Sub + Center + SIDES + Tweeters, )

(9) Modded Lci2 providing extended low frequency coverage to feed to Amp

(10) Digital Audio link, Serial Link, and C-Bus (New)

(11) --------- (to do : Final Conclusions & recommendations based on the above)

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[SCOPESYS]

(1) Sub Speaker Channel
(2018 Honda Premium Audio Revealed Project)

SUB Amp Frequency Response

For Reference, below are typical Frequencies generated by Low Frequency Instruments, Bass Guitar, Drums etc.
(Fundamentals & Harmonics)

So with the current Premium Audio system's SUB, only covers the very LOW Frequency end of Bass Instrument Fundamentals. No wonder there is so little coming out of the Sub speaker .. it's all Vibration Feeling and no Audio Hearing,​

 

[SCOPESYS]

(2) CENTER Speaker Channel
(2018 Honda Premium Audio Revealed Project)

Center Speaker AMP Frequency Response

DTS = ON

DTS = OFF ( about the same - as expected)

Looking Reasonably Good
You could consider it was Flat +/- 3db (ie Flat with some frequencies being 50% louder, and some being 50% Lower)
Still not that good .. If a Home Theater Speaker Audio Response was this bad, one would not be happy.
The Basic amp should be much flatter -- say +/- 1db max.
Will be interesting to see what effects the 3 Tone controls have on this one




(Will Update with Multiple plots, as Tone sliders are set in various combinations)

 

[SCOPESYS]

(3) Front Side Speaker Channel
(2018 Honda Premium Audio Revealed Project)

FRONT side Speaker AMP Frequency Response

AMAZINGLY NON FLAT !!! No wonder it sounds so awful.
The -3db Bandwidth is Meaningless !!
The Pass-band is so non-flat, that one needs to consider the -20db Bandwidth

Appears to be No compression on the Front Speakers with Gain.
Maybe very slight -- or could be measurement accuracy errors.
It's nothing one could "Hear" , even if looking for it.

 

[SCOPESYS]

(4) REAR - Left & Right Speaker Channel
(2018 Honda Premium Audio Revealed Project)

Rear Side Gain is far from Flat ... but its Frequency Filtering does NOT vary with Gain

 

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(5) TWEETER Speaker Channel
(2018 Honda Premium Audio Revealed Project)

( To Do )

 

[SCOPESYS]

(6) LC2i and new SUB AMP
(2018 Honda Premium Audio Revealed Project)

Can't resist it .. screw the warranty -- got to MOD the LCi2 to get it's Sub Output cut-off up a little higher, like 200Hz or even 300Hz !! Then we are talking some serious "Audible" SUB BASS !!

-- 1/2 hour later -- Warranty semi-voided ?
Have not attacked it with a soldering iron yet, and changed any components.
Got my eyes on a few "Filter Circuit" Capacitors already !!

Lci2​

It's all ANALOGUE !! No fancy Digital programmed DSP programming ..
Just simple Op Amp Filter circuits
Should not be too difficult to alter the "Sub Out" Bandwidth, or even make it "adjustable" with an additional pot.

All the hard work is done by using the LcI2 -- and just like the Honda Civics -- the fun starts with the Modding !!!

Thank you "AudioControl"


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​

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Adding the LC2i into the equation is a Game Changer, but maybe only if it is used in the correct way.

MUST use the FRONT side speaker(s) which still have plenty of BASS going to them as input to the LCi2.
Using the REAR side speakers adds little Bass, as the REAR side speaker have most of their lower bass filtered out.​

Increase the Sub high frequency Cut-off from Honda's standard 40Hz to 80Hz, greatly increased the Audible BASS frequency content coming from the Sub Speaker.

 

[SCOPESYS]

(7)
(2018 Honda Premium Audio Revealed Project)

Honda Amp COMBINED SUB + MID + TWEETERS, (No Sides Front or Back or Lc2i )

Each very slight tweaked in gain to get the flattest possible overall response, which turns out to be TOTALLY DISGUSTING, and looking at it while hearing the "Premium Audio" play in the car, explains why it really does sound so "Empty & Hollow" in the mid range, while the door speakers struggle with the low Bass, that should be being produced by the Sub.
SO MANY THINGS seem to be just "WRONG", from the lack of Flatness of the Mid, to the Crossover Frequency .
between SUB & MID.

 

[SCOPESYS]

(8)
(2018 Honda Premium Audio Revealed Project)

 

[SCOPESYS]

(9)
Here are some results of using a Lc2i with a slight modification.

Below is what I wanted to achieve -- The GREEN response
At that time, the response using the Unmodified Lc2i was the Red Profile

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After modifying one of the Lc2i channel's Filter, and then combining the modified channel with the unmodified channel, the measured profile below was achieved.

The final profile is made up of 3 filtered signals, that are mixed together just before entering the new Sub AMP.

This gives the user some interesting options, depending on what Bass sound they want to hear.

(1) Just the Blue - Original Honda Amp sub output, which really is just THUMPS, with no discernible audio frequency that you can hear.
(2) Just the Yellow, that gives the very low fundamental frequency of the Bass.
With just the Fundamental, most bass musical instruments sound the same as each other, and have no individual character (ie No Harmonics)
(3) Yellow with pink added... This gives audible base, where the character of the bass instruments are distinguishable, as there are some of the lower Harmonics included.

Double Bass & Bass Guitar sound like the instruments they are, and can be heard to be different.

(4) All of 3, if you want to hear the bass, and also feel the bass-- assuming you have a powerful enough amp and big enough speaker to render the very low frequency THUMPS.

All 3 of these "Filtered signals: could be mixed with Individual pots, so you could set exactly what you wanted.

At this point, it is getting close to a simple 3 channel DSP, but for sub $100

I ran the output of all 3 combined (2nd Graph) through a small 30W (peak) amp into a 10" Sub... it sounded amazing.. really did not need any more volume.. in fact, needed to be turned down -- unless I wanted the floor to shake !!

Since this seems to work well, next task is to build into a small Plastic "Project Box" the 3 Pots Mixer, and have 3 Phono Inputs and 1 Phono output. (will not need 12v power).

 

[SCOPESYS]

(10)
Digital Audio (Coax) Link between Head Unit and Amplifier.

From what I have measured and observed.. which may be subject to error

The digital Coax link does not appear to be any Industry Standard Link, so will not talk to any standard SPDIF equipment.

All the Audio is passed over this link, as a Stereo pair (ie Just 2 Channels) -- with no high or low band filtering, or volume control, or balance control.

When the Balance or Equalizer controls are adjusted on the Head Unit display, it make no difference to the Digital Audio that is being passed over the link.

The digital audio is sent in two 15 (?) bit frames, with only 12 bits (?) being used for audio information in each frame.
ie 3 of the bits are static,
Pretty sure it is NOT 16 Bit audio

Looks like the update rate is about 48Khz - difficult to measure on scope, as it's near impossible to establish a Frame sync, without decoding the frames to generate a start of Frame 1 sync pulse.

Since this digital link is not a standard used on general Audio equipment (ie SPDIF) , it is not worth delving into any more detail, or trying to decode the frames as there is no real practical benefit in doing so.

What is significant, is that this Digital Audio link is just sending Full Bandwidth Audio as a stereo pair to the Amp, so it is the amp that is doing the Channel splitting to Sub, Center, Front side, Rear side and the tweeters, and setting their high and low filtering.

It is the Digital Control Link (Rs422) that is controlling the amplitudes, equalizer control, and balances of the Audio channels, whose bandwidths are controlled by the AMPLIFIER ... ie The DSP is in the AMP, and not in the head Unit. So control of the DSP in the amplifier is done by sending signals to the Amp from the head Unit, including any DSP FLAT mode settings, over the RS422 link.

BTW: If the RS422 link is disconnected when the Amp is outputting sound, the output stops..because the RS422 is constantly sending data to the AMP, not just when there is a slider change etc..

If the Audio is MUTED, then the HEAD UNIT sends that command over the RS422 link, as well as stopping sending the Digital Audio info... or more correctly, send digital information representing Muted audio.

So the Amp is far more than just a Multi channel AMP, that has a multi-channel digital audio input -- it is a highly integrated part of the Head Unit's Premium Audio system.

While trying to decode the Digital Audio does not provide much practical benefit, decoding the RS422 might be of interest, because this is really what is controlling that the AMP does with it's inputted stereo pair.

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[SCOPESYS]

(11) (last page)
(2018 Honda Premium Audio Revealed Project)

 

[86salmon]

As Topic say, here are actual measured Frequency Responses plots for the Honda Premium Audio system.

Here is the 1st ..(The important one) -- The Sub, at full power out, just below Clip level.
-3db Bandwidth 8 Hz to 40 Hz !!! ( Nice one Honda/Mitsubishi )

As I generate plots for the Center speaker, Side speaker, and side Tweeters, I will add them to this 1st Post, to keep them all together.. (so if you are interest, be sure to check this 1st Post)

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(1) SUB Amp Frequency Response

View attachment 137920

For Reference, below are typical Frequencies generated by Low Frequency Instruments, Bass Guitar, Drums etc.
(Fundamentals & Harmonics)
View attachment 137918

This explains the feels without the sounds of the stock SI system

 

[SCOPESYS]

This explains the feels without the sounds of the stock SI system

After I have got measurements for the AMP (ie without the added effects of the Speakers), I would like to add some "Honda oem speakers) and see what the actual AUdio sound frequency response is, with the effect of the Honda's "Crappy" speakers added into the equation.

So if anyone is upgrading their speakers from a Premium System, and would like to donate their old Honda oem SUB, a door speaker and a tweeter (or any one of those) maybe they would let me have them, rather that the trash bin (which is where they would probably end up).
Private MSG me if you can help out -- I'll cover the shipping.

 

[calonzo]

Just curious, why did you choose to use max output level instead of a normal listening volume level? Wouldn't that be more in line with what we are hearing?

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