2018 Premium Audio System

[Nitroturtle]

This encourages me to continue to peruse the possibility of a "simple mod" to the relatively inexpensive Lc2i, to increase its high frequency cut-off to 100Hz +, while keeping it's low freq cutoff to its existing 50Hz, that combines ideally with the existing Honda Sub, and produces a nice flat response during their cross over.

I certainly have no issues modding the LC2i if it'll yield better results. Looking forward to seeing what you come up with.

Two questions though:

Can you explain what you mean in the quote above about the low versus high cutoff.

Also, what fills in the area circled below? Maybe these two answers are related, I don't know. Just trying to understand it all better. Thanks!

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[SCOPESYS]

I certainly have no issues modding the LC2i if it'll yield better results. Looking forward to seeing what you come up with.

Two questions though:

Can you explain what you mean in the quote above about the low versus high cutoff.

Also, what fills in the area circled below? Maybe these two answers are related, I don't know. Just trying to understand it all better. Thanks!

The BLUE is the Frequency response of the Honda Sub amp.

The Yellow is the response of the LcI2 , being fed with Front Left/Right.

The RED is the COMBINED Frequency response of those two added together.

As the BLUE drops off at Higher Frequency, the Yellow builds up, and since this happens at the optimum matched frequencies, the result is a Flat top to the overall response, which is the happening in the area you circled.


Low Cut off (point) is where the Output drops off (Cuts off) at Low Frequencies
High Cut Off (point) is where the output drops off (Cuts off) at Higher Frequencies

Those points are normally defined as the frequency, at which the output has Dropped by -3dB, 3 db being half the volume (for all intenser & purposes). Yes just 3dB is a LOT @@@

Gain, in dB is a LOG scale.. so is frequency.

Frequency response curves are normally done on Log scales, as this make the region where the output is dropping, a straight line - just make more sense to display it this way on LOG scales, for so many reasons.

That's why ideally, one is looking for the output not to vary by more than a Db, or fraction of a Db, over the Pass Band (The high output , hopefully FLAT part)


The GREEN is what I am aiming for, to be the overall response .. ie by extending where the yellow drops off to a higher frequency. - in effect, giving the LcI2 a wider Pass Band.

Then one has to listen to it, with whatever speaker system one has, and decide if it really does sound better, and if so, go with it, or if not, back to the drawing board, and try something else.

Strangely, a perfectly FLAT frequency response from the speaker outputs, will most likely not sound MUSICALLY that good to your ears. Yes, TECHNICALLY it is Flat / Perfect, but to your ears, that may well not sound as Musically pleasing, and a modified response. Its all very subjective, and varies form people to people, depending on their hearing, and what THEY think sounds good or not.

This is also when talking about the Honda Premium Audio system why some say "It's OK" and some say "It sounds like shit". Depends on the listener expectations and what they have become use to, and also, a lot on how well they are still able to hear !!!

Calling the sound "Shit" does not help much in understanding what they think is "Shit" about it, and very often, that is difficult to actually put into words.

 

[Nitroturtle]

The BLUE is the Frequency response of the Honda Sub amp.

The Yellow is the response of the LcI2 , being fed with Front Left/Right.

The RED is the COMBINED Frequency response of those two added together.

As the BLUE drops off at Higher Frequency, the Yellow builds up, and since this happens at the optimum matched frequencies, the result is a Flat top to the overall response, which is the happening in the area you circled.


Low Cut off (point) is where the Output drops off (Cuts off) at Low Frequencies
High Cut Off (point) is where the output drops off (Cuts off) at Higher Frequencies

Those points are normally defined as the frequency, at which the output has Dropped by -3dB, 3 db being half the volume (for all intenser & purposes). Yes just 3dB is a LOT @@@

Gain, in dB is a LOG scale.. so is frequency.

Frequency response curves are normally done on Log scales, as this make the region where the output is dropping, a straight line - just make more sense to display it this way on LOG scales, for so many reasons.

That's why ideally, one is looking for the output not to vary by more than a Db, or fraction of a Db, over the Pass Band (The high output , hopefully FLAT part)


The GREEN is what I am aiming for, to be the overall response .. ie by extending where the yellow drops off to a higher frequency. - in effect, giving the LcI2 a wider Pass Band.

Then one has to listen to it, with whatever speaker system one has, and decide if it really does sound better, and if so, go with it, or if not, back to the drawing board, and try something else.

Strangely, a perfectly FLAT frequency response from the speaker outputs, will most likely not sound MUSICALLY that good to your ears. Yes, TECHNICALLY it is Flat / Perfect, but to your ears, that may well not sound as Musically pleasing, and a modified response. Its all very subjective, and varies form people to people, depending on their hearing, and what THEY think sounds good or not.

This is also when talking about the Honda Premium Audio system why some say "It's OK" and some say "It sounds like shit". Depends on the listener expectations and what they have become use to, and also, a lot on how well they are still able to hear !!!

Calling the sound "Shit" does not help much in understanding what they think is "Shit" about it, and very often, that is difficult to actually put into words.

Sorry, I should have been more specific with my questions. I understand lowpass/highpass filters and all that. What I don't understand is how both of those curves dipping there combine to a flat output. I think I just misunderstood your proposal with regards to combining the sub+left/right outputs. You are suggesting to only run the left/right into the LC2i, and then AFTER the LC2i combine them with the sub. That makes a lot more sense, and I could see how that combination could possibly eliminate the wedge in the combine curves. Do I have this right?

With that said, assuming I'm correct in the combination of signals you're suggesting, how do you combine the RCA output from the LC2i with the high level signal from the stock sub output?

 

[SCOPESYS]

Sorry, I should have been more specific with my questions. I understand lowpass/highpass filters and all that. What I don't understand is how both of those curves dipping there combine to a flat output. I think I just misunderstood your proposal with regards to combining the sub+left/right outputs. You are suggesting to only run the left/right into the LC2i, and then AFTER the LC2i combine them with the sub. That makes a lot more sense, and I could see how that combination could possibly eliminate the wedge in the combine curves. Do I have this right?

With that said, assuming I'm correct in the combination of signals you're suggesting, how do you combine the RCA output from the LC2i with the high level signal from the stock sub output?

Now you got it ... and you can easily combine the two, with a simple resistor "adding" network.
Once I have actually done it, and figured out what I think is a suitable design,I'll post it so anyone can copy it if they want.

BTW: as far as just using One front side as the input for the Bass audio,

I was listening to some music today on just ONE side speaker, and some of the tracks were almost unrecognizable, without both left & right audio... because of the way the stereo was mixed when recorded.
Now it may be general practice to add the same low Bass to both left & right in a recording studio, but why take that chance, when the LC2I can accept both left & right in, and combine them to the required single MONO sub output.

Note: Stereo SUB in a car is total OVERKILL

 

[SCOPESYS]

After playing with the Premium Audio system today, I am now very confident that it can made a lot better.

Rather than doing subjective listening tests with mp3, and the Honda Mp3 File player, I installed JET HD Player, and started to listen to some Flac files. A world of difference.

One thing that greatly helps, is that "Jet HD Player" has a multi band Equalizer, so it was interesting to alter that, and hear what the effects were on the Honda Oem Speakers.

I have an after-market Car 12" SUB speaker mounted in an enclosure, but so far have not mounted the Test Oem Honda speakers, that were so kindly donated to this project.

For anyone interested, here are a few Pics of the setup I am using.

Honda Hacked Head unit, running off battery (with a Charger). Bank of 4 ohm Load resistors for simulated speaker loads. Scope & Meter. On left is Laptop, with ADB connection to Head Unit - really parts of another Project... Garmin Navigation project.
Far right corner, Right & Left Front Honda Speaks (Not yet mounted) + center speaker.
Behind all this is a SUB enclosure, SUB.

================================

Honda speakers, the AMP (added a fan to keep it cool) and the resistor bank.

Thanks again to the kind Forum member who donated his old Honda speakers after his Speaker update.

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12v Power and simulated Ignition switch. Fuse banks .(easy to short things when testing !!)

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Jet HD Player, running on head unit, allowing far better sub / Bass / Mid ? Tweeter control with its Graphic Equalizer. (Paid version has x2 the sliders of the above)

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ADB root access to Honda Hacked Head Unit --

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Sub speaker enclosure -- old heavy duty speaker box, with new modern 12" Sub.
Honda "Premium Audio" system current strains to get even a little output from this speaker ...
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Need a rest from "AUDIO" this weekend, so I plan to look at the S/PDIF link, and the serial control link.
Have access to a nice "Logic Analyzer" that should easily be able to determine what is going on, and if the S/PDIF is industry standard (would be great),, or a Honda unique protocol.

 

[SCOPESYS]

Looks like the SPDIF may be industry standard 5.1 . UPDATED - No its NOT


Worth confirming, because this may be a game changer for audio update options.
Found a cheap SPDIF to 6 analogue audio decoder on Ebay, so waiting for that to come.
Will be far easier to get a definite Yes/No answer, that trying to analyze the SPDIF waveform with scope & Logic analyzer. UPDATED: NOT SPDIF standard

Serial control .. looks like it is sending "stay awake" messages, as well as Volume & equalizer change info etc. Might try to decode these... would be interesting to be able to control the amp with something other than the Honda head Unit.

Decided to bite the bullet and update the front side speakers in the SI (no matter what ), so I now have those. ( The same ones that the Honda Speaker Donner recommended and fitted when he pulled out the original Honda ones and donated them).
Will be fitting those temporarily into a pair of the Heavy "Good Will" enclosures), to better see what they sound like in a more suitable (optimum) mounted state.

Being able to compare these with the OEM Honda ones in a controlled environment should prove interesting.
The Honda ones do not look that bad .. cone looks nice, Magnet is minuscule though !!!


The Biggest realization (or more precisely, confirmation of what is pretty well appreciated), is that once you start playing music on a reasonably good system, the difference between MP3 and Flac/Wav because increasing striking !!

Unfortunately, the Honda Unit cannot play Flac with it's oem Music File Player, (Can play wav) and any Flac audio that you play on your Smartphione, when sent over Bluetooth, sounds crap, thanks to limitation with Bluetooth

BUT

On a Honda Hacked unit, where you can install a decent Flac Player, with a Multi-Channel Equalizer 16 / 32 channel ( 32 is so excessive !!), it sound FANTASTIC !!

It's like a new High end audio system, even when playing to the Honda speakers, and no additional Amps or Lc2i processing.

Still, almost "Bugger all" comes out of the Sub, but that is to be expected, as I believe that the Honda Sub Frequency range is far from Optimum, and can be greatly improved with the Lci2 and even more with some Lci2 mods.

Listen to FLAC recording on the Unit over the weekend, and at work this week, has been most enjoyable-- sound so much better than the Oem system in the Si.

The Multi-Channel Equalizer is a big game changer .

 

[styxrogan]

Scopesys....u did exact what i did... hack the head unit, install jet audio app, use a big thumb drive with high resolution flac files... change out the speakers with quality speaker and it sounds good.... rears dont have any output compared 2 front...cant even hear them from the front seat... only if u sit in the back seat can u hear the rears... dont sound as good either... I went all out on my speakers....a 10 way dynaudio system

 

[SCOPESYS]

Scopesys....u did exact what i did... hack the head unit, install jet audio app, use a big thumb drive with high resolution flac files... change out the speakers with quality speaker and it sounds good.... rears dont have any output compared 2 front...cant even hear them from the front seat... only if u sit in the back seat can u hear the rears... dont sound as good either... I went all out on my speakers....a 10 way dynaudio system

Yes, I was using jet Audio as well
I understand what you mean about the Rear speakers... especially in a Coupe.

Did you do the Lc2i + Amp for the Sub, or just stay with the reasonably adequate Bass from the front side speakers. ?

With the Jet Equalizer, they can be set to give a more than balanced Bass. Any more is just Excessive Vibration and as far as I am concerned, damaging to the ears.

 

[SCOPESYS]

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).

 

[Nitroturtle]

Nice work.

Would something like this work to accomplish similar results? Was thinking about replacing the LC2i with this to give it a shot.

https://www.amazon.com/Dayton-Audio-DSP-408-Digital-Processor/dp/B07D3H5X5V/

 

[86salmon]

Nice work.

Would something like this work to accomplish similar results? Was thinking about replacing the LC2i with this to give it a shot.

https://www.amazon.com/Dayton-Audio-DSP-408-Digital-Processor/dp/B07D3H5X5V/

You would still need a LOC of some sort to use this DSP. You could use it with an LC2


Edit: my mistake, I only looked at the connections and assumed it only had low level inputs. After reading more about it at Parts Express, sure, why not.

Read all of the reviews and posted questions on PE before making the decision though. Some people have issues with the software. PE had been good with RMA in my experiences with them if you do happen to have an issue

 

[SCOPESYS]

Nice work.

Would something like this work to accomplish similar results? Was thinking about replacing the LC2i with this to give it a shot.

https://www.amazon.com/Dayton-Audio-DSP-408-Digital-Processor/dp/B07D3H5X5V/

Yes, I think that a REAL DSP like the one you found would be more flexible, and the price difference is minimal. Also, to use the Lc12 to the full in the way I described, requires modification, and some other bits (resistors etc).

If you already have a Lci2, then that may be sufficient your needs, especially as I think I have shown, that you MAY get results that you find better, using the Left & Right front inputs, rather than the sub as the input, (many seem to be using the sub alone , which I believe is NOT the right way to go).

From what I have learnt so far, especially over the past few days, I would go with a modest DSP over the Lc2i as a solution to improve and alter the soundscape to what I think I want. Far more flexible, and customizable, and the remote control, is a nice feature as well.

Just a question of picking the right DSP, without going mad and spending a fortune on an overkill.

The one you listed does seem to be a good fit, between features & cost.

 

[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.

 

[SCOPESYS]

86salmon,

How did you mount your after-market Front Door speakers ?

The original Honda Ones have a Plastic surround, with a latching part on one side that seems to go into a slot, and the opposite side takes a single screw/bolt (?) to hold it the whole assembly in place.

Are there holes already in the car's panel to attach a standard speaker with screws, or is it necessary to drill hole to match the speaker's mounting holes ?
(I have not yet removed the door panels to see whats there

 

[86salmon]

86salmon,

How did you mount your after-market Front Door speakers ?

The original Honda Ones have a Plastic surround, with a latching part on one side that seems to go into a slot, and the opposite side takes a single screw/bolt (?) to hold it the whole assembly in place.

Are there holes already in the car's panel to attach a standard speaker with screws, or is it necessary to drill hole to match the speaker's mounting holes ?
(I have not yet removed the door panels to see whats there

I used the adapters by American international with gasket tape between the door and the adapter as well as between the speaker and the adapter

You can also use snips to cut away the plastic surrounds of the factory speakers and screw the replacements into those. which I did in the rears

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