Car audio: Does a premium head unit improve Apple CarPlay sound quality

Does it even make sense to invest in a costly head unit for my Maruti Baleno when all the processing will happen on my Apple iPhone?

BHPian lucksin recently shared this with other enthusiasts:

So a quick background - I am quite fed up with the stock head unit that came with my Baleno. There is a factory low pass post 10khz and high pass post 40hz. This means no matter what I do I won’t get any frequency post 10khz on the upper end and 40hz at the lower end.

Now I ordered an Alpine unit W660E which got installed but has to return it cause there was another upfront cost of 8k for the steering interface plus Bluetooth cost, plus change in faceplates etc etc and the cost was going up to 35-36k.

Now since I will always 100% of the time will use CarPlay for music, and I have an active setup with DSP, does Android or other brands like Sony and Pioneer make a better purchase than Alpine?

For my use case, does it even make sense to invest in a costly head unit when all the processing will happen on my iPhone? I do not know the chain of events in the case of CarPlay hence, I would request anyone who could shed light on - whether a Sony/Pioneer head unit with 4V output would yield better results compared to an Android head unit with 4V output compared to system like Alpine where I will never use their onboard DAC for either Bluetooth or flash drive.

Would deeply appreciate any insight on this.

Here's what BHPian navin replied:

Before I start, please pardon the clarifications. I am not very computer literate.

I assume you are using Spotify (or a similar application on your iPhone) to download music from the internet. You then send this music over CarPlay to your Alpine HU. The Alpine HU has DSP, and you have added separate amplifiers to send the music to good branded speakers (JL Audio, Focal, Morel, etc).

If this is correct, your source is already limited, especially in dynamic range, and changing the HU will serve no purpose. Have you tried streaming Apple Lossless from Apple Music?

The quality of the DAC and having a nominal output of 2V or 4V has no bearing on the sound at this stage.

Consider audio as a chain with Source > Processing > Amplification > Speakers. If your source is the limitation, changing other elements in the chain offers little or no advantage.

Here's what BHPian thirdmainroad replied:

Yes, the HU does have a part to play with audio quality. With a DSP, the trick is to keep the EQ on the HU neutral and adjust the EQ on the DSP. Even then, the output will depend significantly on the HU.

I’ve got a mid/high end DSP - A helix P Six ultimate and hook Apple CarPlay with my stock Taigun HU and achieve pretty decent sound. The Taigun's stock isn’t too bad apparently and must stay because it’s connected with the car readings and controls. Note that the DSP costs 2.5 L though!

I strongly believe Apple Music has the highest quality.

The absolute highest quality will be achieved connecting the phone to a DAC which is connected to the DSP directly, but I’ve been avoiding doing so myself - though I think I will go that way shortly, I am really throttling a very expensive setup with poor input.

There are a few Alpine HUs that audiophiles will swear by - there’s one for some 60 K that’s apparently killer.

The higher end Pioneers are pretty good too. On a previous setup of mine, I had a Pioneer Z series (I’ve forgotten the model - but it came with wireless CarPlay and cost around 50k back in 2018) hooked to a cheaper DSP, which cost around 70k... again, forgotten what it was. But sound was pretty good on that setup as well. Never had a Sony, and I haven’t really had a high end installer ever talk about a Sony. They do talk about Alpine or Pioneer.

Basically, you’ll need a HU which supports High Res audio.

Unfortunately, good sound requires big bucks. You’ll need to shell out at least 50k for a decent enough HU.

What DSP do you have?

I wouldn’t touch any Androids!

Here's what BHPian Kosfactor replied:

You could look at powering the DSP+AMP directly through Bluetooth without an HU present at all.

But in any case you need something good to receive the audio from phone without which it would be useless to have a premium music subscription.

So if you are looking at in-dash Carplay, Android Auto + good quality music - you will spend the big bucks for a Sony/Pioneer type set up, the cheaper no name brands won't work.

Check out BHPian comments for more insights and information.