135i audio upgrade plan

[RPM90]

So, as I wait for my 135i to be made and be shipped, I'm now going to obsess about what to do with my audio upgrade.
I did not get the upgraded audio. I will have the standard audio setup that comes with the US 135i.

My plan is to keep the stock HU for full function and integration of the steering controls. I've read that the stock HU puts out a good 5V signal.
That is fantastic for a stock HU. I'm going to use a 3-way setup for the front using the underseat speaker locations. There will be 1-12" sub in the trunk, and I'll run the rear speakers as fills when needed, using the stock speakers and stock amp power. This pretty much what I did in my 325i, except for the 3-way setup in the front.

I'm going to tap at the stock amp "in" wires from the HU to get my 5V feed, using the Front Left and Front Right signals. This will feed my RockFord amp for both the front components and bridged channels for the trunk sub. I'll just split the 5V signal to feed the front and rear channels on my amp.

These Xover freq. are just guesstimates for now.
The sub will get a 100hz down Xover. The front out from the Rockford amp will go to a 3-way Xover. If there is wiring in the trunk harness that leads to the sub and front components, that would be great.
120hz up to around 500 for the speakers under the front seats. I don't know if the stock subs can handle these frequencies, but if not, I'll try to find some good 8" bass drivers. If I can't find that then I'll use my Audiobahn 6.5" in the underseat location, and simply make an adapter to mount them in the stock box. These Audiobahn drivers have an excellent bass-midbass. They should easily handle 120hz-500hz.
The 4" mids will run about 450hz to about 1800hz/2khz. The tweets will handle everything else. The 1" silk dome Audiobahns tweets have an amazing ability to cover the upper frequencies and develop a nice soundstage.

I'll be feeding 125watts RMS to each front setup, and 425watts RMS to the 12" sub. The rear speakers will be stock and will be driven by the stock amp, and only used for a "fill" or when I have guests in the back.

The biggest problem I think will be getting a the correct 3 way Xover.
Can someone give me some info on this; how are the stock components crossed now? Is there a stock Xover at the speakers, or in the amp?
I think from what I've read that BMW simply used an inline capacitor to control frequency to the tweets? That is a really cheapo way to go, and not the best, nor really a good way to go for sonic clarity.

So, has anyone else tried this setup?
Trunk mounted sub
3 way component setup in the front using the underseat location for the bass/mid bass.

What is the mounting depth for the 8" drivers under the seat?

[strike4A]

I would definitely get an AudioControl LC6i to prep the signal from the HU before you connect to any amps.

[RPM90]

Originally Posted by strike4A

I would definitely get an AudioControl LC6i to prep the signal from the HU before you connect to any amps.

Why? Have you seen the signal coming from the HU?
Is it not clean?

I ask because I've read here that the signal from the HU is clean. It's the amp that has the processing. Also, I don't have the DSP system, so now artificial 'space' should be coming from the HU.

I'm going to need a 3 way Xover. I hope to find one for a good price, but if not then my brother can build me a pair.

I'm thinking now that maybe I could go with 6x9" woofers in the under seat location? I've always like the bass sound from 6x9's.

[strike4A]

Originally Posted by RPM90

Why? Have you seen the signal coming from the HU?
Is it not clean?

I ask because I've read here that the signal from the HU is clean. It's the amp that has the processing. Also, I don't have the DSP system, so now artificial 'space' should be coming from the HU.

It's not a proper pre-out coming from the HU. I tried running it straight to RCAs into an Alpine PDX-5 (which supposedly can accept balanced/differential inputs) and got strange results.

[Citizen Z]

Originally Posted by strike4A

It's not a proper pre-out coming from the HU. I tried running it straight to RCAs into an Alpine PDX-5 (which supposedly can accept balanced/differential inputs) and got strange results.

Yea, its a strange level output. Too high to be pre amp output, to low to be an amplified signal. Thats one of the main reasons I got a 3sixty.2. It really does a flawless job managing the signal and outputting RCA level to the amp.

[RPM90]

Originally Posted by strike4A

It's not a proper pre-out coming from the HU. I tried running it straight to RCAs into an Alpine PDX-5 (which supposedly can accept balanced/differential inputs) and got strange results.

What happened?

According to a member on the E90 AV forum, the same nonLogic HU in the 3 and the 1 puts out 5V. If true, that is an excellent pre level.
Also, seeing that there are only 2 wires + and - coming from the HU per corner, that would be a standard unbalanced connection.

When I modded my 325i "professional" HU I used the HU pre outs and they worked great.
I wonder whats different now?
Even then people said I has to use some like the PDX, but I didn't and it worked great.

Are you guys adjusting sensitivity properly to your amps?

If I have to go with the PDX, then that's what I'll have to do.

[strike4A]

Originally Posted by RPM90

What happened?

According to a member on the E90 AV forum, the same nonLogic HU in the 3 and the 1 puts out 5V. If true, that is an excellent pre level.
Also, seeing that there are only 2 wires + and - coming from the HU per corner, that would be a standard unbalanced connection.

When I modded my 325i "professional" HU I used the HU pre outs and they worked great.
I wonder whats different now?
Even then people said I has to use some like the PDX, but I didn't and it worked great.

Are you guys adjusting sensitivity properly to your amps?

If I have to go with the PDX, then that's what I'll have to do.

It's definitely a balanced output coming from the HU. Put a speaker across the terminals and you will get sound.

In my case, the PDX-5's input sensitivity is 0.2-4V and the HU outputs max 5V so there's a potential issue there straightaway.

Using an LC6i or equivalent means I can adjust the levels accordingly with amp gains at the minimum.

[RPM90]

Originally Posted by strike4A

It's definitely a balanced output coming from the HU. Put a speaker across the terminals and you will get sound.

In my case, the PDX-5's input sensitivity is 0.2-4V and the HU outputs max 5V so there's a potential issue there straightaway.

Using an LC6i or equivalent means I can adjust the levels accordingly with amp gains at the minimum.

At 5V pre out will still drive a speaker 5V is plenty to move the coil, but a 5V pre out gives very nice clean signal, give of course that your amp can handle the voltage.
Also, that would be 5V max at full output, generally most system never get that far as most don't exceed 12 O'clock.
Have you run a meter to the HU out's to see exactly what it was putting out?

"Balanced" output has nothing to do with an outputs ability to drive a speaker.
I don't see any wiring for a "balanced" output. Balanced outs use 3 wires, +, -, and ground, and have a different impedance.
If you run a balanced signal to an unbalanced input you'll get a 6db drop in signal, very noticeable.

If these are balanced outs from the HU, please explain how this is?
Thanks.

[RPM90]

Anyone? Anyone?
Beuller?

Hmm

[Citizen Z]

Originally Posted by RPM90

Anyone? Anyone?
Beuller?

Hmm

Sorry man, you're on your own for that kind of a setup. I've never fiddled with a three way and honestly, the 8" sub goes down to 40hz just fine. For your trunk sub I wouldn't go any smaller than 12" subwoofer with at least 600watts-ish RMS level performance. The reason being the seats will dampen sound so much you're not going to hear or feel much until you start getting ridiculous. While you're at it you'd better make sure you have enough battery given the peculiar charging system the 1er uses.

[Technic]

Originally Posted by RPM90

If these are balanced outs from the HU, please explain how this is?
Thanks.

They are balanced as there is a +5V and a -5V at the outputs of the OEM HU/iDrive computer.

There are plenty of posts in all BMW forums for the last 10 years on the BMW balanced outputs in the 3 Series OEM HU/Nav tuner. This is nothing new.

[RPM90]

Originally Posted by Technic

They are balanced as there is a +5V and a -5V at the outputs of the OEM HU/iDrive computer.

There are plenty of posts in all BMW forums for the last 10 years on the BMW balanced outputs in the 3 Series OEM HU/Nav tuner. This is nothing new.

If there are specific technical posts in the BMW forums, can you give me some? I can't find any. All I find is the same information and terminology being repeated, but no on having any explanation as to why they are using the terms they are using.
Of course, this could be more information than anyone there can give.

If there is no ground, then has anyone tried using one of the hot signal wires and system ground, for signal input to an amp?

Do you know the impedance of the signal wire from the HU?

[Technic]

Originally Posted by RPM90

If there are specific technical posts in the BMW forums, can you give me some? I can't find any. All I find is the same information and terminology being repeated, but no on having any explanation as to why they are using the terms they are using.
Of course, this could be more information than anyone there can give.

If there is no ground, then has anyone tried using one of the hot signal wires and system ground, for signal input to an amp?

Do you know the impedance of the signal wire from the HU?

I think that you are making this complicated, when it is absolutely not. Either get a balanced inputs-compatible amp or use any Audiocontrol device to interface the BMW analog outputs HU to any aftermarket system.

That's it.

For anything else you will have to find the specs on your own by trial and error. BMW doesn't publish any OEM audio specs other than amp output and perhaps frequency bandwidth/THD, and that's in the best case.

[RPM90]

Originally Posted by Technic

I think that you are making this complicated, when it is absolutely not. Either get a balanced inputs-compatible amp or use any Audiocontrol device to interface the BMW analog outputs HU to any aftermarket system.

That's it.

For anything else you will have to find the specs on your own by trial and error. BMW doesn't publish any OEM audio specs other than amp output and perhaps frequency bandwidth/THD, and that's in the best case.

Thanks, for the obvious.

If you don't know the answer, that's cool, just say so.

Nevermind.

[RPM90]

Originally Posted by Citizen Z

Sorry man, you're on your own for that kind of a setup. I've never fiddled with a three way and honestly, the 8" sub goes down to 40hz just fine. For your trunk sub I wouldn't go any smaller than 12" subwoofer with at least 600watts-ish RMS level performance. The reason being the seats will dampen sound so much you're not going to hear or feel much until you start getting ridiculous. While you're at it you'd better make sure you have enough battery given the peculiar charging system the 1er uses.

I do have a 12" sub. It was/is powered by 425rms, and even in a 325i trunk with no split seats, it still had plenty of low end to give a nice sound.
The 135i has even more air pass capability and a smaller cabin.
Remember, I'm looking for a great listening system, it doesn't have to be a system where I have to feel it.

3-way systems are like 2-way systems, except they use a midrange.
That way you have true "sub" freq. coming from the sub, the bass coming from the bass driver, midrange, and tweets.
It gives you a better mid-bass performance and gives a more cohesive soundfield by allowing better frequency separation.

Peculiar charging system?
Ok, now I have to look into why that comment was made.
If you'd care to explain what you mean, that would be great!

[Technic]

Originally Posted by RPM90

Thanks, for the obvious.

If you don't know the answer, that's cool, just say so.

Nevermind.

I do know pretty much all the answers to your questions, guy. It is you that either does not know how to search or you are just lazy. Your attitude points towards the latter.

And I can't just help you with that.

[RPM90]

Originally Posted by Technic

I do know pretty much all the answers to your questions, guy. It is you that either does not know how to search or you are just lazy. Your attitude points towards the latter.

And I can't just help you with that.

I just want to clear up something here.
I have apologized to Technic for the way I addressed him.

For the record I do know how to search, and I am not lazy.
Also, I would like to help others with more direct knowledge of the 135i audio system once I get my hands on my 135i, VERY soon I hope. It should be here by the end of June or early July.
I have done many car audio installs over the years, so I'm not a newbie to this. I was asking my questions as I needed some more knowledge and clarity on the BMW setup.
My questions were a bit more advanced than the typical questions I've seen on these forums, thus, doing searched didn't give me what I was looking for.
My questions about "balanced vs unbalanced" are very specific and more in depth than most searches could give. I researched my questions and spoke with a car audio engineer at Peripheral (audio equipment), and with a "tech/engineer" at Rockford Fosgate, though he seemed more a "tech" than an engineer, given his comments.

I setup my 325i a few years ago, and it's nearly the same as the 135i.
My background is in audio/video production and all related electronic equipment use and setup. However, I am NOT a car audio "expert" in terms of knowing all the technology available today.

Technic, I have some additional questions for you.
In another thread, search induced , you say the OME HU output is "low level", "albeit high voltage". Can you explain what you mean by that?
I'm confused why you said that, but maybe you meant something else by it?
Please explain if you will.

[Technic]

Originally Posted by RPM90

Technic, I have some additional questions for you.
In another thread, search induced , you say the OME HU output is "low level", "albeit high voltage". Can you explain what you mean by that?
I'm confused why you said that, but maybe you meant something else by it?
Please explain if you will.

Some times when low level outputs are mentioned in threads somehow it is implied that it is 2V at the most because that's what commonly low level signals are in voltage. These OEM HU outputs are 5V low level, which put them in a "way above average" category among HU in general, as very few HU (OEM or not) have that high voltage low level output signals.

[RPM90]

Originally Posted by Technic

Some times when low level outputs are mentioned in threads somehow it is implied that it is 2V at the most because that's what commonly low level signals are in voltage. These OEM HU outputs are 5V low level, which put them in a "way above average" category among HU in general, as very few HU (OEM or not) have that high voltage low level output signals.

Yes, I see what you were getting at before.
RCAconnection is considered "low level", and speaker voltage is "high level". In comparing one HU to another, a HU that puts out 5V pre to one that puts out 1V, it should simply be called
a "high voltage output" RCA, as it's relative to the terminology.

Running the OEM HU out and converting it using something like a Peripheral converter does work pretty well. I setup up my 325i that way.
This time I may try a line driver and maybe eq depending on which one I go with. My Rockford amp had very good gain adjust even when using lower voltage RCA in.

Thanks again.

[BBK]

As far as low passing your 12", I would low pass it lower than 100hz. Usually anything above 80hz will make it sound boomy.

[RPM90]

Originally Posted by BBK

As far as low passing your 12", I would low pass it lower than 100hz. Usually anything above 80hz will make it sound boomy.

Yes, I'll tune it once I get everything in. At this point I'm just thinking in the "ball park" for xover points.

It'll make a difference too, if I go with under seat drivers as subs, or if I use that location for bass/midbass and go with an actual sub.

[quality_sound]

Well I was lookin' around on some sites today and found a few different mids that would work in the OEM door location. The Scan-Speak 12M/4631 G 4" mid is only 48.4mm deep. Focal has a couple of 3" mids that will fit as well. Hybrid Audio L3 should fit as well but I can't access the site from work to verify. The Hertz HL70 and EM100 will fit. Renaissance (used to be Morel USA) has some 3" and 4" drivers that will work as well as Morel.

For the underseat woofer, if the frame will fit in the goofy OEM shape, a Hertz Space 8 will fit. It's only 42mm deep. That's the only 8 I can think of that's that shallow but i'll keep my eye out.

Most .75" and 1" tweeters soudl be pretty easy to drop into the OEM locations.