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Discussion Starter · #1 · (Edited)
I decided to investigate the Individual Audio feature, known as option 752. As with most BMW options, information is sprinkled throughout the internet, most of it is correct and most is not complete... so I recently purchased an Individual Audio amplifier from an E92 M3 and hooked it up to my E61 to experiment.

First, some background:
- Option 752 (or SA752 or S752A or $752) is typically called Individual Audio System outside of the USA, whereas inside the USA it was marketed as Enhanced Premium Sound (EPS)
- When first released in the USA in March 2007 (model year 2008) it was only available on the M5 & M6, see the 1 page PDF
- Later it became available on the M3, X5M and X6M in the USA... but outside of the USA it was available on every 3er, 5er, X and likely others
- Rated to 825 Watts for 112 dBA (versus Logic7 amp at 420W according to the 2003 training literature)
- The original amplifier housing has a 3 sided piece of extruded aluminum, having 4 total "fins", 40A fuse near the connectors and preparation for a fan (but no fan installed)
- Later amplifers went to a cast aluminum housing with 3 total "fins", no fuse, added connector for Power and Ground supporting 6 mm2 gauge wire and an active fan
- Both amplifer housing designs say "TOP HIFI M Verst" and "AMPH1" on the label
- Details on the speakers are in the 2 PDFs (note: page 2, all 3 columns, 3rd bullet should say "front" door not "rear" door)
- Surround sound decoding as Dolby Pro Logic II is selectable in the iDrive sound menu
- Same equilizer settings as the Logic7 system
- The amp manufacture is Lear Corporation
- If you find information that conflicts with the above, let us know below and I'll correct this post!

Coding:
My E61 has Hi-Fi (option 676), which only has an amplifier for the 2 under-seat woofers. Fortunately this Hi-Fi amp uses the same 20 pin connector as the Individual amp. I removed the 4 line level input and 1 remote turn on wires, connected to the Individual amp. Then I removed the 4 pin housing from the SDARS (Satellite Radio) connector and connected the MOST cables to the Individual amp. Lastly I removed $676 from my list of FA options in NCSExpert, added $752 and was welcomed with a new ECU to select: "MAMP". There are only 2 options to code in the MAMP, that being the vehicle type and DIRAC bypass. The coding file used was AMPH1 (index C02), matching the label on the bottom of the amplifier. Note that it uses AMPT70.PRG, so you need to select the E70 when communicating using INPA... where I found the amplifier was manufactured in Feb 2008 and flashed with newer software in March 2012 to become part number 7-842-965 with software version 9.3.7. INPA also lets you check internal temperature and send a specific frequency test tone at a certain volume to the speaker of your choosing - very flexible! I recommend starting with -40 dB, as the default -20 dB is a bit loud. In the screenshot I selected -40 dB at 85 hz and sent it to the right subwoofer - where it plays for about 6 seconds and then stops.
After coding the MAMP for the E61, I default coded the CCC_GW, CCC_ASK and CCC_APPL, rebooted the CCC and had 2 new screens in Audio settings. See pics.

First audio test:
I temporarily hooked up 5 more speakers to the 20 pin connector (they are from an E70 Hi-Fi system). I have to say it sounded pretty clean even with the speakers just sitting in back. The bass is excessive, though I seem to recall the Individual under-seat woofers have a higher impedance, which might explain the difference. Turning on the "surround" setting definitely removes the voices from the rear speakers and you just get effect sounds.

In the next post I'll play with ISTA+...
 

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I have Individual Audio (option 752) in my Canadian-market 2009 550i. It is fantastic, and meets all of my sonic requirements. I suppose some true "bass heads" might be unimpressed with the lack of window-shattering lows, but from my perspective, the lows are plentiful, clean and well-controlled. This is the first system I've had in any car (not a huge sample size) that allows eye-watering volume with no audible distortion.
 

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Discussion Starter · #4 ·
ISTA+ shows a new ECU on the MOST bus, specifically the AMPT. There aren't any Service Functions related to the amplifier, but the ECU Function allows you to see the unit's software version, part number and usual identification fields. Under Diagnosis Scan you can see the internal temperature and under Component Trigger you can send a test tone to the speaker of your choice. You have 10,000 Hz and 1,000 Hz for the 7 speakers and 100 Hz for the subwoofers.

In the next post I'll remove the amplifier circuit boards and take some pictures...
 

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Discussion Starter · #5 · (Edited)
The main amplifier ICs are of the "slug" up design which places the metal heat sink contact on the top side of the IC, so I didn't see the IC part number... perhaps I should have cleaned one off? I'd guess all 6 audio IC's are the same, with 4 of the IC's outputting 2x 75 watt (the 8th channel unused), plus 2 remaining bridged for 2x 150 watt (one to each subwoofer). 7x 75 watt + 2x 150 watt = 825 watts. Maybe it's a NXP TDA8922C?

Here is a list of some of the IC's I found on the board.
2x STMicroelectronics P85NF55 Power MOSFET
4x STMicroelectronics STTH1602CR Diode Array
1x Sharc ADW95011Z
2x Analog Devices AD1833 Multichannel 24-Bit 192 kHz DAC
1x Texas Instruments UC28025DW PWM Controller
1x Oasis OS8104AAQ Network Interface Controller for MOST
1x STMicroelectronics ST10F276-CEG 16-bit MCU with MAC unit

List Price for a new amplifier is almost $2000!

I have one more test, then this unit will be for sale - as I have other priorities for the E61.
 

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Hello, rippjd.
You did great work realy. My way was much easy - i upgraded from logic 7, my e61.
Did you investigate were it's in idrive menu "- Surround sound decoding as Dolby Pro Logic II is selectable in the iDrive sound menu" ?
Also i was try to code Bypass Dirac channel in Off and On, and no difference in first look. May be you already investigate this parametr's key? It's very intresting for me.

Now i have 2 different amplifiers - one marked "AMPH1 Top Hi-Fi M verst" and "AMPT70 Top Hi-Fi verst" from e70. It's same by hardware, both allow coding for 752 option. In ISTA-D they both have name as AMPT70. The difference in sound in the depth of stereo panoramas and subwoofers. AMPH1 play better low frequences, but AMPT70 from e70 play much better all, but a little bit worse low frequences. I think it's software settings inside. But how we can tune it? )))
 

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Does anyone have the output specifications of each channel on the amplifier? I am looking to add aftermarket underseat woofers and want to make sure they are at the same impedance.
 

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Yes! I found this topic. What does coding CCC_GW, CCC_ASK and CCC_APPL mean? Please tell us more.
Add new FA with $752 in CAPPL, CAUDI, CGATE, CHOST, CTUNE ?
 
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