Modifying OEM head unit for un-eq’d line out

[ean611]

I have no problem with cutting traces or de-soldering caps. In my lab, I can even re-connect the traces should the need arise.

 

If you could provide the instructions, I'll try it on Monday. (I'll drive the wagon into work and perform the rework in my lab). I would rather turn the caps, but that's me.

[utc_pyro]

I didn't manage to get any pics over the weekend (I forgot to borrow my GF's DSLR), but you should be abel to figure it out. You just need to de-soilder C207, C201, C307 and C301. They are on the bottom of the board toward the tuner from the audio pick-up points. You can see my sim on it in post 60.

 

Oh, and I really envy you for having a lab like that. We have out own intresting stuff in the lab here, but not anything that low of level.

[ean611]

so I should be able to remove those four caps, and keep the solder points on post 27, and I'm good?

 

(busy with other things, and I only have the 2006 schematic, not the 07/08 in front of me)

[utc_pyro]

Yep, you should be able to. The schematic for the 05 and 07 is the same in that area. Physicaly they are in slighty diffrent places, but electricaly it's the same.

[mars_volta]

Wow, I leave for a while and boom!

 

Nice work guys.

 

Do the bass, mid and treb controls still work after the loundess delete?

[ean611]

Wow, I leave for a while and boom!

 

Nice work guys.

 

Do the bass, mid and treb controls still work after the loundess delete?

 

Haven't had a chance to turn the caps yet, but the bass, mid, and treble controls are part of the main ASIC, where the loudness is between the main ASIC and the amp.

 

EDIT: Just turned the caps. I'll report back when I get home and reinstall the radio

[utc_pyro]

Wow, I leave for a while and boom!

 

Nice work guys.

 

Do the bass, mid and treb controls still work after the loundess delete?

 

It'll still work, those are further down the audio path. The only thing that will probably change is the volume will not be the same level as the setting pre-mod.

[ean611]

utc_Pyro, you had that PCB for a line driver, anything come of that?

[utc_pyro]

The origianl one wasnt actually needed, as you could not get any more gain out of it without destortion. I was going to modify mine with a +/- 12V DC-DC converter and make a new version of the board to support it presuming enough demand. Though tecnically, you could run the V1 board off +14V (Vs +8V now) and get ~4.5Vrms

 

I need to find the time to put the prototype together, but I think I can get to that this week. I need to figure out were the higer rated caps I got for it went off too...

[ean611]

utc_pyro: The loudness delete....if you don't remove those for caps (C201, C207, C301, and C307), you're missing out bigtime.

 

I just reinstalled the radio....and it's damn good. Mind you, not good enough to make me give up my Eclipse CD8053 in my Sedan, but for the Wagon, it's damn nice. The only volume issue I had was using my Rockbox'd iPod to play a FLAC file of "Foreplay/Longtime" by Boston, and it wasn't that loud, but that's due to the source. On most music, the max volume is plenty loud.

 

The setup (05 Wagon):

Modded OEM Radio

Rockford Fosgate Type RF X4.C (highs)

Kicker ZR240 (sub)

Kicker CompVR 10 (some old rev from 2-3 years ago)

CDT Audio CL-61A Components (front)

CDT Audio CL-6EX Coax (rear)

 

The setup is very nice all things considdered. If I end up with some spare cash (Ha!, my house is eating all my cash), I'll drop a Rockford Fosgate 360.2 into the mix.

[mars_volta]

Is it too early to celebrate?

[ean611]

Is it too early to celebrate?

 

No

 

Following solder points on post #27 and disconnecting C201, C207, C301, and C307 works as good as this radio is going to.

 

The output is limited to 2V peak to peak, which is in line with very low end after market radios. (Voltage level, not sound quality). Sound quality is decent. A line driver or EQ (such as Rockford 3Sixty.2) will solve that.

[dr_sharp]

There is absolutely no need for a sound processor if you have quality amps. Quality amps can drive a 1V p to p signal with no problem. The problem is that most people buy shit amps and think that they are awesome and complain when things don't work right. 2V peak to peak is enough to drive 99% of every high quality amplifier out there...

[ean611]

There is absolutely no need for a sound processor if you have quality amps. Quality amps can drive a 1V p to p signal with no problem. The problem is that most people buy shit amps and think that they are awesome and complain when things don't work right. 2V peak to peak is enough to drive 99% of every high quality amplifier out there...

 

I would have to disagree, as the line driver I'm recommending is a 3Sixty.2...and that doesn't just boost the voltage

 

A car is an absolutely horrible acoustic environment. An EQ makes such a difference. I have a full RTA setup I can demonstrate this with, but believe me, equalization matters.

[dr_sharp]

I would have to disagree, as the line driver I'm recommending is a 3Sixty.2...and that doesn't just boost the voltage

 

A car is an absolutely horrible acoustic environment. An EQ makes such a difference. I have a full RTA setup I can demonstrate this with, but believe me, equalization matters.

 

Well now we're talking about 3 different things.

 

1) I was talking about peak to peak voltage and using line drivers. A 2V or even 1V signal should be plenty for an amp. I did mention sound processor but I was speaking purely on signal voltage.

 

2) You bring up a good point about the car being a terrible environment. Increasing signal voltage or adjusting EQ will not change that environment

 

3) Sure the 360 is different. I can't argue that adjusting EQ could help. I was speaking purely on signal voltage

[ean611]

Well now we're talking about 3 different things.

 

1) I was talking about peak to peak voltage and using line drivers. A 2V or even 1V signal should be plenty for an amp. I did mention sound processor but I was speaking purely on signal voltage.

 

2) You bring up a good point about the car being a terrible environment. Increasing signal voltage or adjusting EQ will not change that environment

 

3) Sure the 360 is different. I can't argue that adjusting EQ could help. I was speaking purely on signal voltage

 

Ah, that's correct, 2V p-p signal voltage should be enough, but given the amp I'm using, (Rockford Type RF X4.c) at max gain, I cannot get enough volume with any music mixed before the loudness war.

 

With a different amp and different speakers, YMMV.

 

This technique should eliminate loudness even while using the stock HU without an amp, which would also be a very good benefit.

[utc_pyro]

It's closer to 6V p2p (~2V RMS) with test tones. Gains greater than 1.3 or so on my line driver clipped it (8v supply, fet based op-amps). My DMM was also reporting a little over 2V RMS with a 1K tone. That said, I've yet to get a scope so I dont know 100% for sure.

 

Also, even though I have a 3sixty.2, I DO NOT recomend them. Just not enough flexability to do even simple active setups. Even using it with my KAC-X4R (amp with DSP), I think I'm going to loose fade control. About the only way to keep fade control, even having two DSP's, is this:

 

4-channel audio from radio goes to 3sixty.2, NOT set on "sum" mode. Pass the front channel out full range to the KAC-X4R, limiting EQ under ~150 hz, and NO time alignment. Use the DSP in the Kenwood to split the front signal into a 3-way output (High channel A, Mid Channel B, Sub line level out), do the time alignment, sub 150hz EQ on the midrange, and be limited to a 60hz high-pass on the midrange. Take the sub and center outputs, and feed them BACK into the 3sixty.2. Use the 3sixty.2 to further sharpen the crossover and EQ the sub. Feed the rear and sub channel out to the XR-4S.

 

With the sub passing through the DSP's three times, who knows how much delay it will amass just from the that. I dont think I'll have enough time alighment range to bring everything back inline.

 

Just get the Bit1 and be done with it. I wish I did....

 

how do you like the CDT Audio coaxls? I'm considering them for the rears. They have some with neodinium based magnents and slim mounting depts, a plus as I'm going to run the rears just to please passengers.

[ean611]

the CDT audio coaxs are ok rears. Since I hate them attenuated for front listening, I don't hear them much. They do their job without being obnoxious or distorted.

 

I know what you're talking about with fader control and the 3Sixty.2. Personally, I don't care about fader control, because once I set up my levels, I'm good.

 

If you ever want to get rid of the 3Sixty.2, I could use one for the wagon...

[utc_pyro]

I'm looking around for neodymium based woofers for my car if you have any suggestions. I'd like to get my headunit in and start on my next audio hack: getting the media hub with BT streaming working on these older radios.

 

Oh, and incase you're waning DSP, I found these little things that I really wish I had bought instead:

 

http://www.diymobileaudio.com/forum/member-product-reviews/80665-minidsp-excellent-alternative.html

 

Two of those and I could do everything I wanted to, EASY. Probably could use them as line drivers as well.

[mars_volta]

cool!

[utc_pyro]

I never hooked up that DC-DC converter to my little amp board. I was reading a bit more into grounding for audio and I really messed those boards up in that regard, so it would be noisy as heck.

 

Any way, I hooked my '08 radio up to my scope today. I noticed a few odd things.... First, if the head unit clips, it does so SMOOTHLY. It puts a nice round cap on the wave. Not good to cause, but it could be worse.

 

Messing with the bass, mid, and treble setting the unit WILL clip above "30" on the dial. If you use a MS-8 or the like, use this as your setup point.

 

It looks like there is some distortion, normally at 3x frequency.

 

I'll see what else I can find out now that my scope is working. Oh, and this is a 1.5vrms max output. My DMM lied about that.

 

Note: On the attached, the red is out of the radio, blue is out of a PAC line driver.

 

I'm looking for a '09 HK radio to do a step-by-step walkthrough on and test for changes vs the '08. If you have a spare you'd like to sell, please let me know.

[ean611]

UTC_Pyro, did you run your test with the loudness kill?

 

On my loudness-killed 08 radio, there is little to no distortion at high volume (30+) on normal audio sources (iPod and radio) (I almost never use CD).

[utc_pyro]

If I can get a second (third if you count the '06 one?) radio I will. Again, I like some loudness correction in my audio sources as I often listen at low volume. I dont want to do it to the unit I'm going to use full time unless it's the only way to sorrect out issues in the sound.

 

I cant actually HEAR destortion when listening to music and such, but it's showing up on test tones and on the spectrum graph. Low frequancies look particulary strange. That said, I'm not sure if what I'm seeing is coming from the DAC in the CD player, the SRS WOW/input selector chip, the master volume control chip, or my cheap crappy USB scope. I bought this one mainly on it's logic analizer section, I think I need to buy another one with better analog ability.

[ean611]

utc_pyro, I would recommend trying the radio without loudness. You'll be pleasantly surprised I think.

 

Setup in the 05 wagon is CDT CL-61 components, front, CDT Coax rear, Rockford Fosgate Type RF X4.C amp, Kicker ZR240, Kicker CompVR10 (silver front), it sounds pretty good for a setup without an EQ.

[mars_volta]

Just got the fronts wired in for now. Sounds good! A little boost is needed but very usable. Ive got an old alpine monster eq with sub control...I might add that in.

 

This really seemed to help clean up the main speakers. It also does not cut out at vol greater than 30 anymore! Hooray! I think having speaker level input connected really killed it.

 

My radio has the MP3 cd playback. Model P-203UE. It also has other components on the board (sub out?), different layout and a dark silkscreen. I'm not sure what year it is. My original 05 radio is in a box.

 

http://sixthsphere.com/storage2/images/c7xdpdp5xs8crg4za42z.jpg

 

You can see my line in mod in this pic.

 

http://sixthsphere.com/storage2/images/7w357h07n25jtu80dqp.jpg