Car audio -- sound quality in a noisy environment

I love a good stereo in my car, and I’ve chased that dragon nearly as much I have with home audio. I’ve done plenty of aftermarket units where it makes sense, and upgraded speakers and amps where I didn’t want to muck with the factory headunits. And today, factory car stereos are pretty good these days, with auto manufacturers partnering with Bang & Olufsen, Mark Levinson, Bowers & Wilkins, etc…

I moved on from mp3-quality a while ago, generally playing audio from USB sticks with CD-quality FLAC files, or CD’s themselves, or my phone with Tidal downloads, etc…

But occasionally I’ll stream using Bluetooth and the sound quality is actually really good. Really good. Like, “embarrassed I can’t tell the difference between wired connection” good.

My Audi also has a couple of SD-card slots for music. So I picked up a 256GB card and transferred all my FLAC files (ripped from CD). But I quickly realize that the Audi’s SD-card size limit is 32GB, and I don’t think it can read FLAC. So I’m probably going to have to convert everything to AAC or mp3 or whatever and compress it into 64GB. At first I was, aw, crap. This isn’t gonna sound good. But I’m guessing if I pick a higher bit rate like 320k, it’ll sound just fine. I bet I won’t even be able to tell the difference in the car.

We spend so much time creating the perfect home audiophile rooms, with bass traps and noise cancelling insulation, and we remove ticking clocks, and we relegate mac mini’s to a separate room so we don’t hear their fans.

I’m just wondering, in a car, with its road and engine noise being an inherent characteristic of the listening space (even a nicer, luxury car), how good the sound quality really needs to be? Yeah, you want great speakers and a good amplifier, but what about the bit rates?From what I understand, my iPhone’s bluetooth connection certainly isn’t lossless. And not sure about the associated BT connection in my Audi.

Anyway, trying to enjoy the music and the convenience of the car’s built-in system, without rabbit-holing myself into thinking everything has to be (or can be) the same as home.

I expect the Audi will recognize larger SD cars if they are formatted Fat32.

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interesting, I’ll try.

But I think I’ll still have to convert to something un-FLAC-y

EDIT: YESSSSS. FAT32 allows the SD card to be seen. THANKS @Elk

FLAC still no good but I can batch convert them to 320k AAC files. I think that should work for my needs.

But, back to the discussion: do car audio files need to be as hiqh quality as the files we listen to at home?

I am surprised that the luxury cars haven’t added a flac converter. What would be the cost, $100 tops, versus $1,000 for 4 or 5 more speakers?


You can improve SQ dramatically in a car.
My recommendation, get a processor from Audison and go full active. Ditching the passive crossovers make a world of difference. Time alignment, active crossovers, EQ if you want it. BAM


Toslink to processor is my plan

Sometime car makers go down some really bizarre dead ends. My 2009 C2S Carrera has a “Bose” made by Becker, system that plays 5.1 surround DVD A and other formats like MP3s and such. Wha? The car is a pretty noisy sports car… the sound system is really mediocre at best but 5.1 DVD A?

Anywho… I have established that the devil for this car is in the amplification… but the “amp” is a combo unit of DSP (DVD A etc…) and amplification under the seat. It connects to the big head unit in the dash via a proprietary protocol to pass all these crazy formats.

From being on the Porsche forums… I really think I am the only one who ever even knew about the DVD A capability.

I spent lots a time and money upgrading tweaking blah blah blah… it is still a crappy environment… but we soldier on.

Bruce in Philly

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So, just a quick review of this. I saw “Audi” in the name and assumed it was an add-on to the Audi MMI sound system; some kind of seamless integration.

But it appears to be a system unto itself? No integration with the car’s existing stereo? (Looked through all the FAQ’s but didn’t see anything.)

Again, I get that these things are out there, bringing Hi-Res audio into the car. But I’m just trying to gauge with road/engine noise, if Hi-Res really can be appreciated over CD-quality. (Or higher-bit-rate AAC, etc…)

Depends on the ears I guess.

Its less about HiRes but getting a processor with a decent DAC in it and then active crossovers to your speakers so each component gets a dedicated line to the amp.

Audison processors integrate well with factory. They can even deEQ the garbage the factory systems do and you can start from scratch.


Here check this
Amp with DAC/DSP built in

Sorry that was for 24V systems,



To answer your question is it worth it, 1000% yes. If you want musicality yes. Road noise will effect the frequency response but doesn’t touch musicality and engagement.

Budget $500 for component set up front, you should not run rear speakers.

4 channel amp for front. 2 channels to tweeter, 2 channels to mid.

Chatted with the local car-audio place, and they have an Audison expert.

Sounds like a full integration would run in the $5K range. (Audison makes great speakers, he says.)

I’m not averse to that kind of investment, but I’ll probably live with the car for a while first!

In the meantime, I’d love to figure out what the difference in sound quality is between these two sources:

  • AAC 320K files on an SD card

  • Tidal download (CD quality) via Bluetooth (iPhone to Audi MMI)

They both sound fine in the car, so I’m not gonna wring my hands over it too much, but just curious about how lossy the BT connection is.

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Edit - for your current car it’s a little tricky depending on the implementation.

One issue with the iPhone is SQ degrades when using a lot of the common apps. I believe the poor processing algorithms compound on top of Bluetooth for pretty bad degradation.

You can significantly boost your Bluetooth sound quality by using the Neptune app on iOS. It uses better processing for the resampling and the 64 bit engine makes a different with BT. It only plays local files however.

The 320kbp on SD card may sound better since you avoid BT which is bad overall; which everything is converted, even AAC, to Bluetooth codec. Depends on implementation your source though, hopefully the SD card input is implemented decently?

What processor was that quote range for? Bit One, Bit One Virtuoso?

I don’t use iTunes. I’ll download tracks from Tidal to the iPhone. So, the files reside on the phone, but are only playable from the Tidal iOS app. I can configure the Tidal app to download the lossless CD-quality files, but I am not sure if they are FLAC files. (Even though that’s what Tidal uses for streaming.)

I think that some Bluetooth codecs, like aptX, etc, are better than others. But I also know that Apple does not use the aptX codec, it uses AAC. Confusing to me because AAC (Advanced Audio Coding) is not only a filetype (compare to mp3), but is also a bluetooth codec, right?

Not seeing the Neptune app for iOS. Do you have a link?

The Audi also has a wired glovebox port that I can connect the phone to, but I’m finding the bluetooth connection to be more reliable and easier to navigate, oddly enough.

No idea how the SD card input is implemented.

There are also Carplay components I can add to the car, that plug into and integrate with the Audi interface, and those are tempting, too. (I have carplay on my VW R32’s kenwood stereo, and I know it has zero to do with sound quality, but I love the familiar interface.)

Didn’t get into details with the guy. Was just a phone call and we talked in general terms, and I asked him for a ballpark of what one of these installations might cost.

My bad, it autocorrected to Neptune for some reason. Search for Neutron. I think it’s $10… To move files over, plug phone into computer and go to the file directory of the phone and move files to the Neutron app. The whole process with Neutron is not the most user friendly and there are a ton of settings. Just a heads up, but the SQ is really good.

The Audison Bit Play would be cool for you since you could stream lossless from your phone over WiFi.

I’ll have a look. Trying to determine if it integrates with (or can play downloaded files from) Tidal

At this point Neutron doesn’t but the feature has been requested. The issue with the downloaded files is Tidal makes them invisible so you can’t drag and drop them into the Neutron folder.

Outside of Neutron I have tried a bunch of apps, Amarra, Vox, etc… they all basically do nothing for SQ compared to Neutron. Hopefully Neutron adds the feature.