[Pavlo]

Having a discussion with someone about the professional HU on a base stereo system, and trying to clear up if the OEM EQ curve didn't exist on the 2005 Alpine HU and that it changes through out different HU models/years.

He says

"That earlier Alpine HU did sound different to the later units that came in MY2007. The later HU sounded much brighter, it actually sounded like it had some top-end.

Again my 2010 head unit also sounds very different to that same early Alpine. The latest unit sounds very bright, again similar to my later 2007 head unit, but also it sounds like it is distorting going into the Alpine amp, which my early Alpine doesn't, and again the later 2007 head didn't.

So there are differences.

It almost sounds to me as if the very early 2005 Alpine has no EQ on it."

Were as I'm saying "If your car has base stereo the HU is coded to the same OEM EQ curve"

But I can't be certain as I cant find anything what backs up either point.... hmm

What do we know about these HU and how they are coded to base stereo, model/year relation....?

[montr]

I did some measurements on my 2010 base stereo HU. See:
http://www.e90post.com/forums/showthread.php?t=461636

[Pavlo]

Originally Posted by montr

I did some measurements on my 2010 base stereo HU. See:
http://www.e90post.com/forums/showthread.php?t=461636

Yes montr I saw that thread of yours long time ago, it's an awesome write up... Do you know if this applies to all the HU "stereo" coded...?

[VP Electricity]

Pretty sure he has only tested one car.

We've tested multiple cars. I'm confused about why you are talking about a 2005 head unit when we are talking about the E9x platform and it started in 2006. This person you are talking to - have they ever tested the head unit? Do they know how? If they don't, don't listen to them, as they are not giving you data - just telling you an anecdote.

What are you trying to do? What's your goal here? Are you trying to analyze your car's signal?

[Pavlo]

Originally Posted by VP Electricity

Pretty sure he has only tested one car.

We've tested multiple cars. I'm confused about why you are talking about a 2005 head unit when we are talking about the E9x platform and it started in 2006. This person you are talking to - have they ever tested the head unit? Do they know how? If they don't, don't listen to them, as they are not giving you data - just telling you an anecdote.

What are you trying to do? What's your goal here? Are you trying to analyze your car's signal?

I have asked for source... I guess his saying he can hear it. hmmm

We are discussing the E81/7, and someone doing the standard "level 1 upgrade" audio upgrade.

My advice was to look at the how he was going about the OEM EQ curve.

Too which someone posted:

"Alot of the pro HU already provide a flat signal... so it doesn’t need any DSP.
mainly it’s the 2010YOM you want to worry about, they have the lowest grade audio."

And this other person posted to basically agree with that person, and he is the one who quoted the original discussion point.

What I'm trying to do is understand if the OEM EQ curve is universal on all HUs with Base Stereo.

Goal is to show to both OP and this person that the EQ curve is important to tackle.

[VP Electricity]

Originally Posted by Pavlo

What I'm trying to do is understand if the OEM EQ curve is universal on all HUs with Base Stereo.

Goal is to show to both OP and this person that the EQ curve is important to tackle.

OK, in the US, we have only had base Stereo as an option in the 2010 and early 2011 model years. So I cannot speak to what a 2007 head unit for a base Stereo system for the UK might have been doing, since I've never had one to test.

But based on the way the Alpine upgrade packages work, I'm confident that the system works the same for all model years for that platform.

I've seen people say they can hear the difference in head unit output. Based on my experience, those people are full of crap.

But the way to test it is easy. Buy True RTA from True Audio.com ($40 US). Buy a set of Radio Shack meter probes ($5 US). Buy a 1M XLR cable ($10 US). Buy a 30dB XLR attenuator ($15-20) and an XLR-to-USB adapter (Icicle or MicMate, $50 or so, available from musician equipment shops).

Hack the XLR in half and splice the meter probes onto the XLR cable. Plug it into the attenuator and plug that into the XLR-USB adapter.

Now make a Pink Noise CD using the free download from the Rockford site.

Now, for $125, plus your Windows laptop or netbook, you can test the output of the head unit yourself.

[Pavlo]

Originally Posted by VP Electricity

OK, in the US, we have only had base Stereo as an option in the 2010 and early 2011 model years. So I cannot speak to what a 2007 head unit for a base Stereo system for the UK might have been doing, since I've never had one to test.

But based on the way the Alpine upgrade packages work, I'm confident that the system works the same for all model years for that platform.

I've seen people say they can hear the difference in head unit output. Based on my experience, those people are full of crap.

But the way to test it is easy. Buy True RTA from True Audio.com ($40 US). Buy a set of Radio Shack meter probes ($5 US). Buy a 1M XLR cable ($10 US). Buy a 30dB XLR attenuator ($15-20) and an XLR-to-USB adapter (Icicle or MicMate, $50 or so, available from musician equipment shops).

Hack the XLR in half and splice the meter probes onto the XLR cable. Plug it into the attenuator and plug that into the XLR-USB adapter.

Now make a Pink Noise CD using the free download from the Rockford site.

Now, for $125, plus your Windows laptop or netbook, you can test the output of the head unit yourself.

Cool yep, I did think the same, I really don’t like it when people say they can hear "Grass Grow", it’s just not cool.

I’m going to look how to do that soon, but I would be new to output measuring and the process behind it. But yee I should know these things for myself so people can’t blag it. Plus you and others all know how to conduct these measurements. So it’s important for me to get there too. Just didn’t know what hardware and software I needed. So thanks Ken, now I know which direction I’m heading.