part-no. 75110 - Jehnert Sound Design

Installation instructions 

JEHNERT 

Sound 

D E S I G N 

Production of 

Car-Audio-Systems 

Jehnert 

Production 


of 

Design 

development and 

Porsche 


production 

Str. 15 

of 

70794 


Filderstadt 

Porsche Str. 15 

Tel. 00 49 

70794 

71 58 

Filderstadt 

/ 9 56 99-0 

Heinrich-Hertz-Str. 11 

Fax 00 49 71 58 / 9 56 99-10 

Tel. 00 49 70794 71 58 Filderstadt 

e-mail: sounddesign@jehnert.de 

/ 9 56 99-0 

Fax 

www.jehnert.com 

00 49 71 58 / 9 56 99-10 

e-mail: Tel.: sounddesign@jehnert.de 

0049-711-77 97 87- 87 

Fax: www.jehnert.com 

0049-711-77 78 921 

e-mail: sounddesign@jehnert.de 

www.jehnert.com 

instal.instr.no. 75110FH05/04 

part-no. 75110 

VW BUS T4

C o n t e n t s 

page 

Packing list .......................................................................... 2 

1. Disassembly of the door lining .............................................. 3 

2. Installation midrange and tweeter in the dashboard ................ 4 

3. Panel alignment ................................................................... 5 

4. Handling of doorlining / Installation door panel ..................... 6 

5. speaker cables / Handling of car doors .................................. 7 

6. Insulation of the door lining / car doors ................................. 8 

7. Installation of the door lining onto the car doors .................... 9 

8. Crossover circuit - Speaker connection .................................. 10 

Lodspeaker wiring diagram .................................................. 11 

9. Installation of the speaker-grills ............................................ 12 

Technical Information .......................................................... 13 

Service / fault diagnoses ....................................................... 14 

Guarantee .......................................................................... 15 

Please follow the installation instructions 

“step by step” 

and check the package contents 

Particularly important notes contain the following remarks: 

 

75110 VW Bus T 4 - 1 - © JEHNERT SOUND DESIGN

Packing list 75110 

Packing unit Check list 

door panel, covered (right / left) 

Speaker grill, covered (right / left) 

tweeter 26 mm 

midrange 100 mm Q 

Adapter for midrange and tweeter 

woofer 165 160 mm (each mounted on the paneel with 4 sheet metal-screws) 

crossover (right / left) 

standard cables for subwoofer (right / left) 

2 

2 

2 

2 

2 

32 

2 

2 

Hardware bag: 

flat flat head head screws screws M4 M x 60 4 x 60 

metal screws, 3,9 x 25(for angle fastening) 

Spax screws 3,9 x 25 (for angle fastening) 

metal screws, 5,0 x 80 

Spax screws 5,0 x 80 

metal screws, 5,0 x 90 


sheet metal screws, black 3,9 x 13 (for tweeter mounting) 


sheet metal nuts ø 3,9 mm 

flat round head screw 3,9 x13 

Hex nut M4 

 

sheet 

Washer 

metal 

Ø 

screws 

20mm 

black 3,9 x 10 (for tweeter mounting) 

for metric screws 10x + 4x as spacer for Velcro fastener 

sheet metal nut Ø 3,9 

Velcro strip à 2,5 cm (reserve) 

Preassembled hex nut M4 hardware: 

washers Velcro Ø fastener 20mm plus strips 

velcro flat head strip 2,5 screws cm (Reserve) M 4 x 16 

flat head screws M 4 x 50 

flat head screws M 4 x 30 (right side) 

flat head screws M 4 x 40 (left side) 

sheet metal screw, black 3,9 x 13 (for woofer) 

sheet metal screw, black 3,5 x 13 (for velcro fastener) 16 

The product was carefully packed and checked for its completeness. If you find anything missing, damaged or 

defective, please notice our guarantee services on the back of these assembly instructions. 

75110 VW Bus T 4 - 2 - © JEHNERT SOUND DESIGN 

44 

4 

4 

8 

6 

2 

2 

2 

2 

4 

3 

10 

2 

14 

4 

4 

10 

14 16 

42 

2 

1 

1 

32

1 . Disassembly of the door lining 

A 

C 

B 

1.1. roll down window completely 

1.2. pry out the plastic bolt (A) at the door-innerside 

and pry out the plastic cap at the door lock (B). 

A 

B 

1.3. pry out the plastic cap at the door handle (C) abhebeln and unscrew the 3 

cross head screws underneath. 

C 1 

C 2 

C 3 

1.4. Unclip carefully speaker remove grill. the plastic Dismount clips speakers on the door-lining and unsrew edges the and 3 move the 

door-lining cross head forward screws underneath.. 

away from the inner door metal 

1.5. Carefully disconnect remove the original the plastic loudspeaker clips on and the remove doorlining the Bowden edges and pull move wire. the doorlining 

1.6. 

forward 

Loosen the 

away 

screws 

from 

of 

the 

the 

inner 

original 

door 

tray 

metal. 

fastening and remove the tray. 

1.6. Remove the Bowden pull wire.. 

1.7. Loosen the screws of the original tray fastening and remove the tray. 


2. midrange and tweeter installation in the dashboard 

2.1. tweeter installation on the A-pillar: 

2.1.1. Lead the tweeter cable throgh the opening in the mounting bowl and 

lengthen it with the speaker cable (1,5 - 4 mm 2 ). Measure the cable 

length up to the mount of the crossover under the dashboard (see page 9) 

2.1.2. place the tweeter bowl directly above the original speaker grill - parallel 

to the front glas: 

 

for acoustical reasons the tweeter must radiate parallel to the front glass 

and has not to be directed to the hearer! 

Affix the mounting bowl with a sheet metal screw 3,9x13 10 to the A-pillar. 

Insert tweeter and fasten it with a bajonet socket. 

IMPORTANT: 

Tweeter-position radiate 

parallel to the front glas ! 

2.2. midrange installation in the dashboard: 

2.2.1. pry out the speaker grill and remove the original speaker. 

2.2.2. connect the JEHNERT-midrange 

with a speaker cable (1,5 - 4 mm 2 ) 

Lead the cable to the mount of the 

crossover in the dashboard (page 9) 

2.2.3. Insert insert midrange the midrange with with installation 

installation ring. 

into the original 

Fastening 

mount so 

left 

thhat 

1x 

the fastening cover 

with 

plates 

the 

on 

screw 

the midrange 

3,9 x 13 

match the 

original fastening points. Fasten with 

Fastening 

original screws. 

right 2x 

with the screws 3,9 x 13 


3. Panel alignment 

 

For doorlinings with ventilation flap: 

Some models are equipped with a ventilation flap on the below part of the door lining. 

It must absolutely be sealed or closed! 

3.1. Place the door lining on a plane surface. 

3.2. Dismount the loudspeakers attached to the panel for transport protection. 

Retain the screws for later assembly. 

3.3. Place the panel without loudspeakers on the door lining and align it: 

Align the upper edge of the panel directly on the dept under the 

door handle. 

Reference line 

 

Only precise alignment of the panel with the door lining 

warrants optimal fit. 

picture to page 6 - No.5: 

fig.: backside of the panel 

1 

M 4 x 16 

already 

mounted 

fastening points - Panel backside 

2 

M 4 x 50 

already 

mounted 

3 

M 4 x 30 

already 

mounted 

fastening angular for metal screws 3,9 5,0 x 25 30 

75110 VW Bus T 4 - 5- © JEHNERT SOUND DESIGN

4. Handling of door lining / Panel installation - Fastening 

4. Handling of door lining / Panel installation - Fastening 

1. use the precisely aligned panel as template in order to mark fastening 

1. points use the 1- precisely 7: aligned panel as template in order to mark fastening 

• points mark 1- the 7: fastening points 1-3_ premounted in the panel: 

• pressing mark the the fastening panel to points the door 1-3_ lining premounted leaves visible in the impressions panel: of the screws 

pressing Beginning the with panel fastening to the door 1. lining leaves visible impressions of the screws 

• marking of fixing points 4-7: 

• use marking a thin awl of fixing to set the points marks 4-7: on the door-lining 

use TIP to a thin mark awl angular to set fastening the marks points on 6+7: the door-lining 

TIP put in to mark a little angular bit of packing fastening tape points to this 6+7: position. Measure up the angular position. 

Mark panel edge and angular position on the tape. 

put in a little bit of packing tape to this position. Measure up the angular position. 

Mark panel edge and angular position on the tape. 

2. draw the speakers’ cut-outs onto the door-lining. 

2. draw the speakers’ cut-outs onto the door-lining. 

3. take away the door build. cut out the speakers’ outlines marked by means 

3. of take a compass away the saw door build. cut out the speakers’ outlines marked by means 

of a compass saw 

4. Drill the holes for the screws 

4. Drill according the holes to the for marks the screws set 

before. according Use to a the 6mm marks drill. set 

(fastening before. Use point a 6mm 1 = drill. 10mm) 

(fastening point 1 = 10mm) 

 

5. place the door panel precise again and do the panel fastening in 

5. in place exactly the door follow panel succession: precise again and do the panel fastening in 

in 

fastening 

exactly 

from 

follow 

the 

succession: 

doorlining - backside 

1. fastening fastening from points the doorlining 1-3 secure - backside 

1. with fastening washers points and 1-3 nuts secure 

with (fig. see washers page 5) and nuts 

2. fastening (fig. see page points 5) 6+7 

screw 2. fastening the metal-screws 

points 6+7 

3,9 screw x 25 in into the metal-screws 

the angular 

fastening 3,9 x 25 into and the secure angular with 

sheet fastening metal and nuts secure ø 3,9 with mm. 

sheet 

fastening 

metal 

points 

nuts ø 

4+5 

3,9 

from 

mm. 

Spax 3,9 x 25 Spax 3,9 x 25 

doorlining fastening points - frontside: 4+5 from 

6+7= Spax fastening 3,9 angular x 25 - panel backside Spax - fig 3,9 see page x 255, too 

screw doorlining both - frontside: M4x 60 Screws 

6+7= fastening angular - panel backside - fig see page 5, too 

fastening points 8 - 12 

and secure with washers 

: no pre-drilling 

screw in both M4x 60 Screws fastening with metal screws has to be done directly if installing the 

nuts 

the fastening complete points doorling 8 - 12 

and secure with washers 

onto : no the pre-drilling car door (see page 9) 

fastening with metal screws has to be done directly if installing the 

and nuts 

the complete doorling onto the car door (see page 9) 

All cutting edges of the panel must fit to the door lining snugly 

all All around cutting without edges of gap the panel must fit to the door lining snugly 

 

all around without gap 

8 

8 

1 2 3 

1 2 3 

9 10 

9 10 

4 5 

4 5 

M 4 x 60 M 4 x 60 

M 4 x 60 M 4 x 60 

6= 7= 

6= 7= 



11 

11 

12 

12

5. Speaker cables / Preparation of the car doors 

5.1. Installation speaker cables 

5.1.1. Lead 1 speaker cable (1,5 - 4 mm 2 ) from the amplifier to the crossover 

under the dashboord. 

5.1.2. Lead 1 speaker cable (1,5 - 4 mm 2 ) from the crossover into the 

car door (see wiring diagram page 11) 

5.2. IMPORTANT! Preparation of the car doors: 

5.2.1. remove the original insulation material (foil) completely! 

5.2.2. in order to protect the speakers against humidity close all cut-outs / 

depts on the inner door metal with tar mats or similar insulation 

material. 

5.2.3. to avoic vibration noise tighten all original fastening screws on the 

inner door metal. 

5.2.4. please observe that the speaker cables are not squeezed by any 

mechanic parts (window contrrol etc.) 

5.2.5. IMPORTANT CONTROL: 

hold the door lining with the panel to the car door and check the 

following at the 1. speaker cut-out (see fig.): 

 

 

 

• the factory installed clipped cable has to be displaced downward 

instead of the 1 st woofer in the panel. 

• if need be, knock the door metal internally on this part - the 

woofer in the panel must not be in contact with the door metal. 

IMPORTANT CHECK 

(only for the 1st woofer installation) 

displace the original 

clipped cable downward 

and slightly knock the 

door metal internally 

IMPORTANT: insulate the car door - see description on page 8 


6. insulation of the door lining 

! 

 

attention – danger !! 

No insulation behind the 

side-airbags (fig. B) 

Important: 

No insulation material behind 

- loudspeaker 

- door latch lever 

- (fig. A): drill a hole for the 

installation clip 

 

fig.: example backside of the door lining – insulation with our article no.: 27000 

Important tip: 

the use of 4x160mm 165mm mid-woofer /side may cause vibrations which lead to 

annoying rattle noises in the car door 

some helpful tips: 

• use our self-adhesive insulation fleece (art.no.: 27000) fora 

foam material for 

the backside of the door lining (see fig. above) or 

• stabilize the backside of the door lining by means of a special material 

(Glass Fibre Filler or stiffening material) 

Important: keep the cut-outs for the door-airbags and speakers open 

• affix the *backside of the inner door metal with self-adhesive asphalt mats (see fig. * ) 

• by knocking on the car door, vibrations caused by mechanic parts (e.g. Bowden pull wire etc. ) 

and wiring harness may be found out. Cover these parts with foamed material, felt or 

something like that 

• cut off overlapping cable tie (rattle noise) 

• adhere felt or foamed material under the original wiring harness 

moisture protection foil 

front side of 

inner door metal 

* door metal outside 

= back side of the 

inner door metal 


7. installation of the door-lining onto the the car doors 

7.1. Check up length of the screws and bolts: 

in order to prevent damages of mechanic parts of the car doors, please check 

once again the length of all bolts and screws on the back side of the door 

lining! No touch with any mechanic parts of the car doors ! 

(please shorten if necessary). 

7.2. put the door-lining into the upper sealing of the car door 

tip: grease the upper door sealing with a residue-free lubricant before 

7.3. fit it in contrary order of succession as described on page no. 3 

7.4. carefully screw in the metal screws 8-12 through the door panel and 

the door lining to the door metal. 

IMPORTANT: Do not screw in the self cutting metal screws too tight - 

it deforms the doormetal and affects the normal function of 

the door mechanic! 

fastening point 8-11: 8: Spax metal 5 x 90 screw 5,0 x 80 

9-11: 12: Spax metal 5 x 80 screw 5,0 x 90 

12: Spax 5 x 100 

11 

IMPORTANT: Strong tightening of the screws 

affects the function of the door mechanic! 

10 

9 

8 

12 

 

Final inspection after panel installation: 

• please check all functions of the operating elements such 

as seat adjustment, opening of the glove box, 

window winder etc. 

• no insulation directly behind the speaker ! 


8. Crossover circuit - Speaker connection 

8.1. precable crossovers - see fig. page 11. 

8.2. Recommendation crossover installation: on option under the 

dashboard 

 

IMPORTANT: Do not install the crossover immediately next to 

electrical equimpent 

8.3. Insert subwoofer and connect all loudspeakers to the crossover circuit with 

the included standard cables for subwoofer to the crossover circuit: 

parallel wiring see diagram on page 11. 

Notice: You should check the the polarity of all of subwoofers all after having 

connected before connecting them to them to the to crossover the crossover circuit circuit 

with a 9 a volt 9 volt battery 

(input with a 9 cable volt battery: on the side of the amplifier). 

 

pole of the crossover circuit input to of a 9 Volt battery 

pole of the crossover circuit input to of a 9 Volt battery 

All subwoofers must move uniformly! 

Wrong polarity of a subwoofer can totally 

equalize the bass sound! 


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a n c 

a n c 

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a 

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P 

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Loudspeaker wiring diagram 

Connect all loudspeakers and crossover circuits: 

Circuit diagram of 2-way crossover / 4x subwoofer 

recommended power 

from 200 Watt RMS / 4 Ohm 

amplifier 

JEHNERT 


D E S I G N 

VW BUS T 4 

3-way crossover circuit 

woofer 

INPUT 

tweeter 

midrange 

S p e a k e r 

M A D E I N G E R M A N Y 

T w e e t e r 


JEHNERT 


D E S I G N 

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f o 

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g i 

S p e a k e r 


M i d r a n g e 

JEHNERT 


D E S I G N 

P 

r m 

f o 

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S p e a k e r 


W O O F E R 

JEHNERT 


D E S I G N 

P 

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r m 

f o 

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H 

i g h 

S p e a k e r 


W O O F E R 

JEHNERT 


D E S I G N 

P 

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r m 

f o 

e 

D E S I G N 

D E S I G N 

H 

W O O F E R 

JEHNERT 


H 

W O O F E R 

JEHNERT 


e 

i g h 

S p e a k e r 


a n c 

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S p e a k e r 


= set of cables supplied with 

P 

P 

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r m 

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f o 

f o 

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9. Installation of the speaker’s grill: 

9.1. Precisely align and carefully press grill into the Velcro fasteners. 

 

The Velcro fastener makes a crackling sound 

when it is closed correctly. 

9.2. Our Tip: 

If the panel cannot be pressed on completely at some points. . . 

Cause: 

Solution: 

the special form at these points and the resulting differences in 

material cross section of the grill. 

the distance can be levelled out with spacers 3 under the 

Velcro disc. 

(Spacers included with the screw kit) 

grill 

2 self-adhesive Velcro-strip 

1 Velcro fastener 

3 Washer M4 ø 20 as spacer 

doorpanel 

9.3. 

Removing the grills: 

The Velcro fasteners stick together very strongly! 

The grills can be removed anytime by carefully lifting them off. 

Please, avoid any way of forceful yanking at the grills. 

It could break! 


T e c h n i c a l i n f o r m a t i o n 

Equipment: 

electric window control 

Model/ year: T 4 

Insulation: is absolutely necessary ! - see page 8 

Note about setting: 

To obtain optimal stereoscopic sound, all settings 

on the radio (bass, treble, loudness etc) should be 

set to zero or neutral. 

Recommended 

amplifier power : 

Metal cutwork : 

from 2x 200 - 360 Watt RMS / 4 Ohm 

not necessary 

Cut-outs for loudspeaker/ 4 x 144mm (max.outer dimensions subwoofer 165 mm) 

each side (max.installation depth subwoofer 65 mm) 

DIN-Euro-Norm-standard basket ø 6“ made it fit 

Sound-System: 

3-ways 

4 x 165mm 160 subwoofer/ side 

1 x 100 mm midrange / side 

1 x 26 mm tweeter / side 

car-customized crossover network 

max.continuous Watt/RMS: 

car specific frequency range: 

Total impedance: 

2 x 300/500Watt 

39-22.000 Hz 

4 Ohm 

We reserve the right to make technical changes, as well as development. 


Technical questions: Hotline: 0049-711-77 58 97 / 9 87-87 56 99-0 

Technical questions: Hotline: 0049-711-77 5897 / 987-87 

56 99-0 

It is our pleasure to help you! 

It is our pleasure to help you! 

Self-help and fault diagnosis 


The following notes serve to help troubleshoot and eliminate faults or malfunctions 

on The your following own. If notes the following serve to help measures troubleshoot are not and effective, eliminate please faults call or us. malfunctions 

What on your can own. it If be the if following ... measures possible are cause/ not effective, solution please call us. 

What ..it doesn’t can it sound be if right. ... possible wrong polarity cause/ on solution the subwoofers ( page 10) 

..it doesn’t sound right. crosover wrong polarity circuit on attached the subwoofers wrong ( ( page page 11) 10) 

Mirko Schwarz Doorlining crosover circuit 

Steffen Kretzschmar and moisture attached protection wrong ( Marc page foil 

Sitter 11) 

not cut out ( page 6+9) 

Mirko Development Schwarz Doorlining Steffen Saddlery Kretzschmar 

/ Completion and moisture protection Export Marc foil 

/ Sitter 

Service 

amplifier not cut out doesn’t ( page have 6+9) 

Development 

Saddlery / Completion enough power Export /( Service page 13) 

amplifier doesn’t connection have enough power ( page 13) 

Dear customer, 

amplifier connection 

...it doesn’t fit correctly. door panel customization ( page 5) 

We Dear have customer, taken great care to explain the procedures in our installation instructions 

...it doesn’t fit correctly. door 

more detailed and “step by step”. installation panel customization of the panels on ( the page door 5) lining (page 6) 

We have taken great care to explain the procedures in our installation instructions 

.....grills 

more Your tips detailed 

do and not suggestions and 

hold. 

“step by help step”. installation of the panels on the door lining (page 6) 

observe us for the notes future on to eliminate page 12! uncertainties and 

misinterpretation. Your tips and suggestions Therefore, help please us for inform the future us. what to eliminate you would uncertainties like to be and improved 

.....grills do not hold. observe notes on page 12! 

vibrations or misinterpretation. what we should Therefore, still change. please insulation, inform see us. notes what on you page would like 8 to be improved 

vibrations or what we should still change. insulation, see notes on page 8 

We thank you for your support! 

We thank you for your support! 



The following notes serve to help troubleshoot and eliminate faults or malfunctions 

on The your following own. If notes the following serve to help measures troubleshoot are not and effective, eliminate please faults call or us. malfunctions 

What on your can own. it If be the if following ... measures possible are cause/ not effective, solution please call us. 

What ..it doesn’t can it sound be if right. ... possible wrong polarity cause/ on solution the subwoofers ( page 10) 

..it doesn’t sound right. crosover wrong polarity circuit on attached the subwoofers wrong ( ( page page 11) 10) 

Doorlining crosover circuit and moisture attached protection wrong ( page foil 11) 

not Doorlining cut out and ( page moisture 6+9) protection foil 

amplifier not cut out doesn’t ( page have 6+9) enough power ( page 13) 

amplifier doesn’t connection have enough power ( page 13) 

...it doesn’t fit correctly. 

amplifier connection 

door panel customization ( page 5) 

...it doesn’t fit correctly. door installation panel customization of the panels on ( the page door 5) lining (page 6) 

.....grills do not hold. 

installation of the panels on the door lining (page 6) 

observe notes on page 12! 

.....grills do not hold. 

vibrations 

observe notes on page 12! 

insulation, see notes on page 8 

vibrations insulation, see notes on page 8 



G u a r a n t e e 

We grant a manufacturers guarantee of 2 years starting from the date of purchase 

of the door panels or sound system from the dealer. 

Within this guarantee period to our choice we either repair or replace free of 

charge all defects due to material or workmanship. 

Exempt from this guarantee are damages due to improper use, wear and tear or 

damages which have to be led back on wear or interventions by third parties. 

The guarantee does not cover subsequent damages or such defects that only 

insignificantly impair the value or the usability of the panels/sound system. 

The guarantee does not cover damages due to external influences. 

 

Panels with additional or wrong assembly drill holes cannot be returned. 

These are damages to the panel which cannot be repaired again. 

2004/by.aj/FH - 15 -

part-no. 75110 - Jehnert Sound Design

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