# 2009 Jetta - Stereo Test Results



## nukeman (Jun 26, 2009)

Hopefully the tests I ran this weekend will answer the questions many have posed regarding the lack of lower midrange response in the factory MKV premium system (at least in my 2009 Jetta TDI with the factory premium system (e.g. no separate amp). There is no doubt the factory premium stereo is lacking lower midrange response in the front channel. My measurements indicate a significantly reduced output from about 125hz to 1000hz in the front channel. What is not clear is whether this is due to some equalization being done in the head unit, the factory crossovers and speakers, or some combination of the two. I ran some tests this weekend in conjunction with installation of powered sub which indicate the midrange deficiency in the front channels is due to the speakers and crossovers alone. The test involved first disconnecting the headunit from car speakers and then powering one of my home speakers from the head unit, measuring its response, and then powering the same speaker from my home stereo. The frequency response curves were very close, generally flat, and considering the differences in the location (car versus home) I would say they are identical. This proves there is no factory equalization in the head unit. I measured sound output with a test cd over the range of about 100hz to 10,000hz. So the problem must be solely due to the factory speakers and crossovers. 
To install the powered sub I fabricated a jumper from male and female connector harnesses I purchased from enfig car stereo. One that plugs in to the car wiring and one that plugs into the factory head unit. You just connect the wires from one plug to the wires from the other. This allowed me to tap into the speaker outputs without splicing into any factory wiring. I did have to purchase an extra male connector as the ones they sell don't have all the necessary contacts. In any case, just installing the powered sub was a big improvement. 
The issue remains with the front speakers, but all together the system doesn't sound that bad, its just that the imaging is way off. I am considering the next step which would be to replace the factory crossovers, alone, on in some combination with the factory speakers.


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## jason256 (Jul 9, 2010)

I know this is an old post, but I have some new information that may be useful.

I too have an 09 TDI with the "Premium 10 speaker sound system" and 6-disc in-dash changer with no amp under the seat. Like many other Jetta owners, have noticed the dramatic lack of mid-bass from the front channel. In an attempt to improve the situation I decided to start by replacing the front speakers. From my past experience, speakers are usually the weak link in a factory audio system. After trying two different replacement woofers and eventually bypassing the door crossovers and hooking the head unit directly to the woofers, I still couldn't get any meaningful mid-bass output from the front.

So... I decided to get scientific on the problem. I hooked up a signal generator to the aux input and a Fluke true RMS multimeter to the HU output wires for the front left channel. I used a 500mVpp sine wave, and stepped it through the range of 20Hz to 20kHz taking 50 or so measurements with the volt meter. All measurements were made with the volume control in the same place (I adjusted the volume knob to get ~2Vrms out of the HU at around 800Hz before starting the data logging.) All EQ controls were set to the vertical (0) position. Note that the crossover was totally removed and the HU output was not loaded during the measurements. This is what I found:










All values were converted to dB referenced to an average of the mostly flat area from 1k to 20k. I also took apart the crossover and calculated corner frequencies based on the component values. The woofer side is a 2nd order low pass at 130Hz, and the mid gets a 2nd order high pass at 173Hz. So, that also creates a gap right around 150Hz just like in the response of the head unit. I calculated that the crossover dip should only be 2 to 3dB though. So basically VW put a 12dB digital notch filter and a 2.5dB crossover dip both to knock out 150Hz.

Does anyone know if there are any radio settings that can be changed with vag com that might disable this filter? I have read that the MFD2 has a factory settings menu with the option for mid range attenuation EQ. Does the Premium 7 have a "suck" bit that can be turned off?


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## MuthaFunk (Feb 3, 2010)

I recently upgraded my premium 8 system for the same problem. Although not as scientific as you gentlemen, I am an audiophile and sound engineer who appreciates excellent sound. I left the factory speakers in and think it sounds pretty good. It's not perfect but definitly worth upgrading the head unit. With a little eq'ing by the aftermarket head unit I was able to get satisfactory sound from the factory speakers.

See this thread if interested: http://forums.tdiclub.com/showthread.php?t=287338


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## Poppy231 (Sep 10, 2010)

Hi guys! Just purchased a 2010 Jetta, with the 10 speaker "premium system" I have always had a good ear for good sound and with the minimal adjustments you are able to squeeze out of this touch screen head unit. I still wasnt able to satisfy quest for optimal sound. Its ok for the most part but still want more bottom end and mid-range sound. I am sure if I replaced some of the speakers with some aftermarkets I will get a lil more out of it but , what does one do as far as a head unit? I dont see the aftermarket world replacing something like this on the 2010.

Any ideas out there? PM me if you have heard of anything or done an upgrade. 
Thanks.
Billy


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## zachass o2 (May 6, 2009)

just buy an aftermarket headunit for a 2009??? or any "nice/decent" headunit and wire it up for the car...... they dont have to be for the exact model car you have just make sure they have the same power rating and enough clearance to slide it all the way back. :thumbup:


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## klrman (Nov 7, 2010)

*Anybody try these...*

Anybody try the following?

JL Audio "Clean Sweep" (http://mobile.jlaudio.com/products_cleansweep_pages.php?page_id=79) to correct the midrange dip in freq.? It looks like it would be the ticket to flatten the curve.

or....select a setting in VAG-COM for factory audio: "Byte 5 select Bit 00 – Equalization: Linear" which should remove any equalization trickery.

I'm looking to improve the sound of my system but absolutely do not want to change out my HU.

Thanks,

-t


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## Non_Affiliated (Feb 12, 2002)

jason256 said:


> I know this is an old post, but I have some new information that may be useful.
> 
> I too have an 09 TDI with the "Premium 10 speaker sound system" and 6-disc in-dash changer with no amp under the seat. Like many other Jetta owners, have noticed the dramatic lack of mid-bass from the front channel. In an attempt to improve the situation I decided to start by replacing the front speakers. From my past experience, speakers are usually the weak link in a factory audio system. After trying two different replacement woofers and eventually bypassing the door crossovers and hooking the head unit directly to the woofers, I still couldn't get any meaningful mid-bass output from the front.
> 
> ...


While getting technical on this issue, I ask what impedance is your Home speaker? Most Car audio speakers are 4 Ohm. IIRC the monsoon system has 2 Ohm drivers, but we are not talking about those.

So if you put a home speaker (Normally) 8 Ohms in a car that was designed to run a 4 ohm system then take the same driver and run it on a home stereo designed to drive a 8 Ohm speaker. Then make a comparison between the two, there is going to be some discrepancies. How large dunno, but there will be some.


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## Head_Unit (Aug 18, 2016)

jason256 said:


> ...I also took apart the crossover and calculated corner frequencies based on the component values. The woofer side is a 2nd order low pass at 130Hz, and the mid gets a 2nd order high pass at 173Hz. So, that also creates a gap right around 150Hz just like in the response of the head unit. I calculated that the crossover dip should only be 2 to 3dB though. So basically VW put a 12dB digital notch filter and a 2.5dB crossover dip both to knock out 150Hz.


GREAT research! I want to improve my kid's 2009 and this goes a long way towards explaining the decent yet funny sound. Other notes, in case someone reads this ancient thread:
- At these low frequencies, passive crossovers do not work very well due to interaction with the impedance peaks of the drivers. So all kinds of frequency/phase fluctuations could be going on.
- Jason if you ever read this, what were the component values you saw?


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## Head_Unit (Aug 18, 2016)

klrman said:


> ....select a setting in VAG-COM for factory audio: "Byte 5 select Bit 00 – Equalization: Linear" which should remove any equalization trickery.


How do you get to that to set it?


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