# Sound Processor vs Aftermarket Head Unit



## v.wynn (Mar 27, 2017)

Hey everyone,

I have a 2017 Jetta SE (4 speakers) and I miss the sound quality from my old system. The old parts that I have that I can put in the Jetta are:

Kenwood DDX9902s
Pioneer GM-D9605 
Pioneer TS-D1730c
Pioneer TS-D1602r
Polk MOMO MM2124 

The dilemma I'm in now is if I should install my the equipment I have in addition to a sound processing unit because even with the aftermarket parts, I still wasn't satisfied with the sound quality. However, I don't want to remove the factory head unit because I want to maintain the car's factory mic which I use for bluetooth. With this being said, could you guys advise me on any options to maintain the factory head unit or will I ultimately have to give it up for sound quality. I've read that factory head units have internal sound adjustments that have an effect on sound quality that even a good sound processor can't fix.

Thanks!


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## gijoe (Mar 25, 2008)

Get a good DSP and you'll be fine. There are a ton on the market, so just start searching around here for DSP's and see what fits your needs and budget. Aftermarket head units are quickly becoming a thing of the past.


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## v.wynn (Mar 27, 2017)

gijoe said:


> Get a good DSP and you'll be fine. There are a ton on the market, so just start searching around here for DSP's and see what fits your needs and budget. Aftermarket head units are quickly becoming a thing of the past.


Glad you said that because I just came to this realization about 30 minutes ago. Since there's no amplifier on the factory unit I can just plug the high level input from the factory head unit into the amplifier but this doesn't address the sound tuning that a DSP would provide. So far I'm pretty sold on the c-DSP because it's inexpensive and does what I need it to do.

I'll research this more!

EDIT: The factory head unit may have a low frequency cut off as well as reduced bass when the volume is increased, would the miniDSP C-DSP compensate for this?


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## bugsplat (Nov 7, 2014)

v.wynn said:


> Glad you said that because I just came to this realization about 30 minutes ago. Since there's no amplifier on the factory unit I can just plug the high level input from the factory head unit into the amplifier but this doesn't address the sound tuning that a DSP would provide. So far I'm pretty sold on the c-DSP because it's inexpensive and does what I need it to do.
> 
> I'll research this more!
> 
> EDIT: The factory head unit may have a low frequency cut off as well as reduced bass when the volume is increased, would the miniDSP C-DSP compensate for this?


Not really. You can adjust the input EQ levels at the DSP to equal out the base but you cant adjust for HU volume levels if changed. My Camaro used to do this too. You would have to leave the HU at a set level and use the C-DSP's remote for volume. Not a big deal, Just leave the HU at Vol 20 lets say and use the c-dsp remote.

Good news is you have multiple input options and 1-4 preset buttons on the remote to change from HU to RCA to Digital if you wanted to by-pass the HU all together at the push of a button to flip between them. For the money you won't find better than the Minidsp


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## v.wynn (Mar 27, 2017)

bugsplat said:


> Not really. You can adjust the input EQ levels at the DSP to equal out the base but you cant adjust for HU volume levels if changed. My Camaro used to do this too. You would have to leave the HU at a set level and use the C-DSP's remote for volume. Not a big deal, Just leave the HU at Vol 20 lets say and use the c-dsp remote.
> 
> Good news is you have multiple input options and 1-4 preset buttons on the remote to change from HU to RCA to Digital if you wanted to by-pass the HU all together at the push of a button to flip between them. For the money you won't find better than the Minidsp


Ok great I get this. Since the DSP can't compensate for the build in factory head unit volume bass adjustments, etc. just leave it at one volume and let the DSP tune at that level and control the volume using the DSP so that you won't have to deal with that constant bass decrease as the volume increases. 

Also, as far as using the digital and RCA input on the C-DSP... I plan on using high level input from the head unit to the DSP so how would I go about using Tidal's "lossless" music on my iPhone and get that lossless sound quality to the DSP? I could use Apple CarPlay through the USB built into the car but I'm not sure if the factory head unit will degrade the quality. I know if I get a lightning AV connector then run the HDMI out on that to a HDMI to RCA converter, that's several pass throughs so I'm sure it'll lose quality.


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## Marky (Nov 15, 2011)

There's a lot to be said about the newer car head units and how they are inter-connected with the vehicles ECM. At the same time there's a lot to be said about running a movie on a 8" or 9" H/U to pass the time rolling down the road. A lot of guys are junking the head units and running iPod etc straight into a DSP like a Helix. 

I have a 2006 F250 and as soon as I pull my H/U I'm running that pile of sheit over with the truck. One bit of advice that I have stumbled across is my iPod 5.5 Enhanced model is far and away the best sounding iPod/iPhone I have ever owned. I thought I just had some good recordings on it until I figured out everything on it sounds better. After doing some research it turns out its the best iPod Apple ever produced. I think they were made in 2006 when Steve Jobs returned to Apple and he pushed them to produce a iPod to the best of the technology at that time. They are still sought after and sell in the $80-$250.00 range on eBay depending on what upgrades have been made to them.

I have two of them myself one for my shop system and other one for the truck. Look it up there is truly a superior digital signal in that model.......
Oh yea there was no lightning plug in 2006. Gotta live with the giant 30 pin plug.


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## v.wynn (Mar 27, 2017)

Marky said:


> There's a lot to be said about the newer car head units and how they are inter-connected with the vehicles ECM. At the same time there's a lot to be said about running a movie on a 8" or 9" H/U to pass the time rolling down the road. A lot of guys are junking the head units and running iPod etc straight into a DSP like a Helix.
> 
> I have a 2006 F250 and as soon as I pull my H/U I'm running that pile of sheit over with the truck. One bit of advice that I have stumbled across is my iPod 5.5 Enhanced model is far and away the best sounding iPod/iPhone I have ever owned. I thought I just had some good recordings on it until I figured out everything on it sounds better. After doing some research it turns out its the best iPod Apple ever produced. I think they were made in 2006 when Steve Jobs returned to Apple and he pushed them to produce a iPod to the best of the technology at that time. They are still sought after and sell in the $80-$250.00 range on eBay depending on what upgrades have been made to them.
> 
> ...


If I could install the aftermarket head unit without going through the hassle of figuring out how to retain steering wheel controls, the reverse camera, as well as the internal mic (aftermarket mic never seems to work out), I'd do it. My Maestro SW doesn't work with VW. I did all of that in my previous car and it was a headache to get set up, plus I like the clean look of OEM. 

This kind of leads me into a question regarding sound quality from iPods/iPhones. I know Tidal provides FLAC music.. If I were listening to a FLAC audio file on my iPhone, or a 5.5 iPod, and it was connected to my car via CarPlay (Since Bluetooth compresses sound quality), would this FLAC signal be degraded by the time it reaches my speakers? Since the iPhone is decoding the FLAC signal, the signal is being passed through the head unit, DSP, then amp. I know the DSP and amp won't degrade my sound quality but I'm not sure if the factory head unit will somehow try to compress the digital signal before passing it through. It doesn't "support" FLAC meaning it doesn't decode it so if it doesn't decode it then hopefully it won't touch the signal and just pass it through? Also, CarPlay/USB connection to play music is better than AUX, right?


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## Marky (Nov 15, 2011)

A lot of that goes right over my 52 year old head. What I do know is the iPod 5.5 was the last unit apple made using the Wolfson DAC and its specs out digitally were SNR 94dB and THD 0.0034%
It is direct digital out through its connector using its own Burr Brown DAC. 

How I have always used my stuff "iPods" is through my Alpine INE-Z928HD using the USB port in the back. I just ran a plug over to my glove box and I let her rip through the controls on the stereo screen itself. I have had several different iPods as well as a few iPhones connected the same way and none sound like the 5.5 does.

I literally stumbled across this because I played one from my sons friend. Forget the song but they were bragging about the bass in a song that was on it. So I plugged it into my stereo and couldn't believe my ears. The more songs I played the more I knew it was the best iPod I have ever heard. 
I got onto the web and looked up best iPod made: low and behold the 5.5 Enhanced had all kinds of articles and write-ups on its superiority out of all the iPods.

Not sure how yours will play through your head unit but if you have a direct line in without a DAC it will stream straight in. I do recall Wolfson was bought out by Cirrus and they pretty much run the show now. But they don't make anything today that compares to what Wolfson was cranking out. At least not in any iPhone I've plugged into my home system or old truck stereo.

I'm not up on all the techy stuff but its definitely worth taking a look at the info out on the 5.5 iPod. I love both of mine and my iPhone stays in my pocket anymore.


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## v.wynn (Mar 27, 2017)

That all makes sense! I do remember the sound quality of the first gen iPod nano now that you mention it and it sounded amazing compared to listening to that same song on my iPhone. I never thought to pinpoint it to the DAC. I would jump on a 5.5gen iPod but nowadays I use streaming services like Tidal and Apple Music to download music and it's not compatible with the iPod because it requires installing the app to use. If I purchased albums and ripped them like I used to, it would be a no brainer.

I'm glad to know when you connect your iPod to your HU, the HU uses it's Burr Brown DAC because that means the iPod just sends the clean signal and leaves it up to the head unit to decode the signal. This answers the initial question I had because it tells me the HU is responsible for decoding that. Welp, looks like I'm going to be finding adapters to maintain functionality of things I want in my Jetta because I don't want the factory's HU ruining the sound quality, even if a DSP is involved.

This actually raises more questions because now I know the DAC is responsible for converting digital to analog and the DSP is responsible for processing a digital signal. From what I'm understanding, the HU's DSP will process the initial file from the audio source then send that analog signal to the DSP which will then reconvert it to digital, process it, then send it digitally to the amp, which will then convert it to analog to send to the speakers?


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## Marky (Nov 15, 2011)

v.wynn said:


> That all makes sense! I do remember the sound quality of the first gen iPod nano now that you mention it and it sounded amazing compared to listening to that same song on my iPhone. I never thought to pinpoint it to the DAC. I would jump on a 5.5gen iPod but nowadays I use streaming services like Tidal and Apple Music to download music and it's not compatible with the iPod because it requires installing the app to use. If I purchased albums and ripped them like I used to, it would be a no brainer.
> 
> I'm glad to know when you connect your iPod to your HU, the HU uses it's Burr Brown DAC because that means the iPod just sends the clean signal and leaves it up to the head unit to decode the signal. This answers the initial question I had because it tells me the HU is responsible for decoding that. Welp, looks like I'm going to be finding adapters to maintain functionality of things I want in my Jetta because I don't want the factory's HU ruining the sound quality, even if a DSP is involved.
> 
> This actually raises more questions because now I know the DAC is responsible for converting digital to analog and the DSP is responsible for processing a digital signal. From what I'm understanding, the HU's DSP will process the initial file from the audio source then send that analog signal to the DSP which will then reconvert it to digital, process it, then send it digitally to the amp, which will then convert it to analog to send to the speakers?


Yea I'm with you there, when I start reading up on how things actually run from start to finish I feel a bit dizzy like spinning on a turntable. I just quit the heavy thinking


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## v.wynn (Mar 27, 2017)

Marky said:


> Yea I'm with you there, when I start reading up on how things actually run from start to finish I feel a bit dizzy like spinning on a turntable. I just quit the heavy thinking


It's been more than 24 hours of constant digging, I'm calling it quits. 

I just ordered the adapters necessary to maintain steering wheel and factory mic functionality on my Kenwood and canceled the order of the DSP. Soon as it comes in, I'm gonna stick with my HU, amp, and speakers. Simple and guaranteed effective.


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## Marky (Nov 15, 2011)

Glad you have it figured out at least. I hope you come across a iPod5.5 and can run it through your system just so you can get a comparison on the modern stuff. I have a Pioneer Elite SC07 in my shop that goes to 4 channels of all Beyma Studio drivers that just sounds beautiful. Its almost running all the time I'm in the shop and being the stereo snob I am you can pick out any flaw in any recording with that system. I still remember taking that iPod out there and plugging it in. Was a absolute OMG moment that all three of us just stopped and gazed with amazement at the sound quality coming out of that old iPod. 
Like I said I plopped on the computer and started doing research on it. There is a lot to read about it on the web. Funny how one guy can make or break a company. Steve Jobs was apples saving grace to say the least.

Best of Luck on the stereo. I like the VW BTW my cousin has one with the diesel engine and punishes every Prius that has the misfortune of being in his reach. He blows by them at 100 mph and can still pull down 50+ MPG

Cheers


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