A18 Amplifier

Plug connector overview

Number	X-pin, colour	Description
X10266	42-pin, black	Plug connector Amplifier

Pin assignments at plug connector X10266 (Pin numbers not listed are not used)

Pin	Type	Description / Signal type	Connection / Measuring notes	Wire Color
1	A	Signal, rear left speaker -	Subwoofer, left	BR
2	A	Signal, rear left speaker +	Subwoofer, left	GE
3	A	Signal, front left woofer -	Woofer, front left	RT/BR
4	A	Signal, front left woofer +	Woofer, front left	RT/GE
5	E	Terminal 30	Fuse F102
9	E	Signal, AF radio, front right +	Radio
10	A	Aerial switching signal	Aerial diversity
11	A	Signal, front right tweeter +	Tweeter, front right	BL/SW
12	A	Signal, front right tweeter -	Tweeter, front right	BL/BR
13	A	Signal, rear right mid-range speaker +	Mid-range speaker, rear right	WS/SW
17	E	Signal, AF radio, front right -	Radio
18	E/A	K-bus signal	K-bus connector
21	A	Signal, rear right mid-range speaker -	Mid-range speaker, rear right	WS/BR
22	A	Signal, front right woofer -	Woofer, front right	BL/BR
23	A	Signal, front right woofer +	Woofer, front right	BL/WS
24	A	Signal, rear right speaker -	Subwoofer, right	BR
25	A	Signal, rear right speaker +	Subwoofer, right	BL
26	M	Ground	Ground point
28	E	Mute	Cellular telephone
29	E	Signal, telephone AF +	Cellular telephone
30	E	Signal, AF radio, front left -	Radio
31	A	Signal, rear left mid-range speaker +	Mid-range speaker, rear left	GE/SW
32	A	Signal, rear left mid-range speaker -	Mid-range speaker, rear left	GE/BR
33	A	Signal, front left tweeter +	Tweeter, front left	GE/RT
34	A	Signal, front left tweeter -	Tweeter, front left	GE/BR
37	E	Signal, terminal 50 via vehicle immoblizer	Cellular telephone
38	E	Signal, terminal 50 via vehicle immoblizer	Radio
39	A	Signal, front left mid-range speaker -	Mid-range speaker, front left	BL/BR
40	A	Signal, front left mid-range speaker +	Mid-range speaker, front left	BL/WS
41	A	Signal, front right mid-range speaker -	Mid-range speaker, front right	BL/BR
42	A	Signal, front right mid-range speaker +	Mid-range speaker, front right	BL/RT

Some notes from GV from Belgium concerning specifications of Z4 audio systems:

Originally posted on Z4um by "GV from Belgium"...


This is mostly a copy-paste version of some older posts…

Which sound system do I have in my zzzz?

There are 3 sound systems available for the Z4.

Standard audio: 6 speakers, no subwoofers, no speakers in the doors
Hifi: 10 speakers (including 2 subwoofers)
Top Hifi: upgraded 10 speakers (including 2 Carver technology woofers)

All speakers are made by Philips. The “Carver” woofers are also made by Philips but rumours are that they were designed by Bob Carver like his Sunfire woofer series.

The woofers in the Hifi system have an impedance of 2 ohms
The woofers in the Top Hifi system have an impedance of 10 ohms

All speakers have got a good efficiency (dB/W/m), so keep in mind that in most cases when you replace them with aftermarket ones, the sound pressure level will suffer.

The amp on the Hifi and Top Hifi system is located next to the battery in the trunk.

Top Hifi (also called Premium Audio or Carver):

The Top-HiFi audio system consists of following components:
• Radio Business-CD or CID
• Top-HiFi amplifier
• Front left and right low-range speakers (woofers)
• Front left and right high-range speakers (tweeters)
• Front left and right mid-range speakers
• Rear left and right mid-range speakers
• Rear left and right low-range speakers (woofers) in Carver technology
• CD changer (optional)

Top-HiFi Amplifier
With regard to its functionality, the Top-HiFi amplifier corresponds to the previous DSP
amplifier as already used in other model series. The special features on the E85 are the two high voltage output stages (30 V) for the Carver woofers.
The Top-HiFi amplifier has 2 analogue inputs (left and right). In addition, the Top-HiFi amplifier
features a digital input for the CD changer connection (coaxial cable). This arrangement
achieves a higher signal quality.
The top HiFi amplifier is installed in the luggage compartment next to the vehicle battery.

Front low-range speaker (woofer)
The woofer has a diameter of 160 mm and a paper cone. The maximum load capacity is
50 W. The woofers (low-range speakers) cover a frequency range from 50 Hz to 500 Hz.
The front woofers (low-range speakers) are mounted at the bottom in the A-pillars on the
left and right.

High-range speakers (tweeters)
The tweeter has a diameter of 26 mm and a fabric cap or calotte. The maximum load
capacity is 25 W. The tweeter (high-range speaker) covers a frequency range from 4000 Hz
to 20,000 Hz.
The frequency range of the high-range speaker is set by means of a capacitor.

The tweeter (high-range speaker) is located in a panel mounted in the mirror triangle.
The output direction of the tweeter is directed at the head area of the occupant opposite.
The tweeter (high-range speaker) is based on a sealed design.
Mid-range speaker
The mid-range speaker has a diameter of 100 mm and an aluminum cone. The maximum
load capacity is 50 W. The mid-range speaker covers a frequency range from 100 Hz to
10,000 Hz. The front and rear mid-range speakers are identical.
The front mid-range speakers are fitted in the doors. The rear mid-range speakers are
installed in the partition behind the seats.

Carver woofers (low-range speakers), rear
The Carver woofers have a diameter of 160 mm and a paper cone in Carver technology.
The maximum load capacity is 100 W. The Carver woofers cover a frequency range from
30 Hz to 150 Hz.
The rear Carver woofers are accommodated in the partition behind the seats. The resonance
volume is approx.10 l.

Carver Woofer Operating principle:

High sound pressure is required for achieving a rich bass. The Carver woofers (low-range
speakers) produce this sound pressure with their small diameter by increasing the
displacement of the diaphragm. The sound pressure is produced by movement in the volume
of air.
The volume of air moved is derived from the diaphragm area multiplied by the displace-
To date to achieve this, the largest possible diaphragm area (diameter of the speaker)
was used in conjunction with relatively low displacement (approx. 3-10 mm). A matching
resonance volume is additionally required.
In vehicle construction applications, this technology leads to a conflict between vehicle
design and vehicle equipment: Due to the design and comprehensive level of equipment,
there is little package space available for large bass speakers.
Carver technology represents a new approach in solving this problem. Thanks to Carver
technology, a high sound pressure is produced with a small speaker diameter by increasing
the diaphragm displacement (approx. 30 mm).
Due to the greater diaphragm displacement Carver woofers (low-range speakers) require a
higher voltage supply than conventional speakers.
A special DSP amplifier with high voltage output stages (30 Vrms) is required for the Top-
HiFi audio system. It is necessary to greatly increase the magnetic force in order to achieve
greater diaphragm displacement. The solenoid was adapted accordingly. A high magnetic
force also means that a high back emf is produced in the solenoid (back emf Uemf=B.l.v).
The back emf counteracts the output voltage of the amplifier thus reducing the effective
voltage at the solenoid.
It is not possible to operate Carver speakers with the amplifiers (radio output stages 6 Vrms)
previously used.

Note: The signal from the head unit is sent by the K-bus to the amp. This is a digital signal. Because of this, it is not possible to use an aftermarket HU together with Top Hifi/Hifi amp.


HiFi System:
The HiFi audio system consists of following components:
• Radio Business-CD or CID
• HiFi amplifier
• Front left and right low-range speakers (woofers)
• Front left and right high-range speakers (tweeters)
• Front left and right mid-range speakers
• Rear left and right low-range speakers (woofers)
• Rear left and right mid-range speakers
• CD changer (optional)
HiFi amplifier
The HiFi amplifier is designed as an analogue 10-channel amplifier. The 4 input channels
are divided via frequency gates and equalizing filters over 10 channels. The HiFi amplifier is installed in the luggage compartment trough next to the vehicle battery.
The output power is:
• Low-range 4x40 W
• High range/mid-range 6x25 W
The channels are divided over a 3-way speaker system at the front and a 2-way speaker
system at the rear.

Low-range speakers (woofers)
The front woofers (low-range speakers) are mounted at the bottom in the A-pillars on the
left and right. The woofers are arranged transversely with respect to forward direction.
The resonance volume is approx.10 l and utilizes a part of the sill area.
Rear woofers are additionally installed in the partition behind the seats.

High-range speakers (tweeters)
The tweeter has a diameter of 26 mm and a fabric cap or calotte. The maximum load
capacity is 25 W. The tweeter (high-range speaker) covers a frequency range from 4000 Hz
to 20,000 Hz. The tweeter is connected to the woofer.
The frequency range of the high-range speaker is set by means of a capacitor.
The tweeter (high-range speaker) is located in a panel mounted in the mirror triangle.
The output direction of the tweeter is directed at the head area of the occupant opposite.
The tweeter (high-range speaker) is based on a sealed design.

Mid-range speakers
The mid-range speakers have a diameter of 100 mm and a paper cone. The maximum load
capacity is 25 W. The mid-range speaker covers a frequency range from 100 Hz to 15,000
Hz. The front and rear mid-range speakers are of identical design.
The front mid-range speakers are fitted in the doors. The rear mid-range speakers are
mounted behind the seats. The front mid-range speakers emit sound transversely with
respect to forward direction. The mid-range speakers utilize the resonance volume of the
doors. The output of the rear mid-range speakers is aligned in forward direction. The resonance
volume is approx. 2 l.