Alfa Romeo Forum banner

1 - 12 of 12 Posts

·
Registered
Joined
·
20 Posts
Discussion Starter #1
While I apprecite this is going to give me far from perfect sound quality, I'd like to know the simplist way to get an audio & power feed to my subwoofer from a standard set-up.

First instinct says splice into one of the rear speaker wires, but I suspect one of you will have the answer without me having to do the trial and error.

Thanks a million AO!

:thumbs:
 

·
AO Silver Member, 155 Lounge Winner 09
Joined
·
7,713 Posts
can you tell us exactly what model powered-sub you have?

the principles involve:

1. powerwiring: +12V feed, fused, directly from the battery; wire-gauge depends upon the power of the amp (and its current draw); and the GND (groundwire) directly to the chassis

2. trigger wire: an IGN (ignition) or 'switched' +12V powerwire that turns the amplifier on/off; 0V when your ignition key is at OFF, and +12V when the key is ON; only those amplifiers with 'auto signal sensing' do not need this (ie: those amplifiers that can automatically detect when an audio signal is fed to them, and they turn on/off accordingly)

3. audio signal: best quality is via low level RCA connection, but this is not offered by the factory headunit; so you need to rely on the high level speakerwire signal: tap into the speakerwires (rear L/R channels is fine) and feed to the highlevel inputs on the amp; if the amp has no highlevel inputs, then you will need a line output converter (LOC; aka LineLevelConverter or HiLo Converter); this connects to the speakerwire highlevel signals, then drops the level down, and has low level RCA output terminals for connection to the amp

:)
 

·
Registered
Joined
·
20 Posts
Discussion Starter #3
Thanks for the quick response!

I've got an Infiniy Basslink. Stats couresty of our friend the internet!

10" subwoofer and 10" passive radiator with built-in amp
Power Output: 200W
Frequency Response (±3dB): 20Hz - 100Hz
Variable Bass EQ: +3dB to -6dB at 45Hz
Variable Electronic Crossover: 70Hz - 100Hz
BassLink provides user-adjustable input sensitivity, crossover frequency and bass-boost.
Four low-level inputs
High-level inputs allow interface with most factory systems.
200-Watt Class-D amplification.
 

·
AO Silver Member, 155 Lounge Winner 09
Joined
·
7,713 Posts
i presume that is 200WRMS (root mean squared). website isn't clear. i also tried downloading the manual without success. given it is class D topology (and therefore about 80% efficient), will probably have a 20A fuse (ie: draw up to around 20A at full volume).

so you don't need huge, thick powerwiring. in fact, 12awg (american wire gauge) is rated to 30A continuous. though i'd go with something thicker over the length of 5~6m; 8awg is easy to acquire at an ICE store, and so too terminals and fuseholders to suit. use the same gauge for the groundwire, with a ring terminal crimped onto the end, and bolted to the chassis's bare metal (remove any paint).

it has highlevel inputs to suit connection to your speakerwires.

without the manual, not sure if it requires the remote/ignition trigger wire, or whether it has auto sensing.

:)
 

·
Registered
Joined
·
20 Posts
Discussion Starter #5
:thumbs:
Thanks for the advice! All wired in and sounding brilliant.

Took me about 2 hours to sort find a grommet and run the power lead through the bulkhead but managed it in the end.

Stereo popped out pretty easily and tapping in the extra wires was fairly easy with an extra pair of hands.

Running the wires down the car went without a problem and I even managed to inadvertantly run power and audio down different sides of the car. Turns out this is best practice (as most of you will already know!).

Only problem I have now is that the Sub box slides around a bit. I don't really want to make holes in the boot or damage the plastic liner. Any ideas??
 
N

·
Guest
Joined
·
0 Posts
Heavy duty self-sdhesive Velcro. ;)

(Just stick the spiky side onto the sub, that should
give it enough grip to stop sliding around.)
 

·
AO Silver Member, 155 Lounge Winner 09
Joined
·
7,713 Posts
glad you installed it without much trouble. enjoy.

i was going to suggest velcro too. :)

:)
 
A

·
Guest
Joined
·
0 Posts
:thumbs:
Thanks for the advice! All wired in and sounding brilliant.

Took me about 2 hours to sort find a grommet and run the power lead through the bulkhead but managed it in the end.

Stereo popped out pretty easily and tapping in the extra wires was fairly easy with an extra pair of hands.

Running the wires down the car went without a problem and I even managed to inadvertantly run power and audio down different sides of the car. Turns out this is best practice (as most of you will already know!).

Only problem I have now is that the Sub box slides around a bit. I don't really want to make holes in the boot or damage the plastic liner. Any ideas??
Which one did you go for in the end?

I'm looking to wire the BOSE sub up without the standard BOSE loom and wire it up manualy.
If thats not viable I'm looking at using a Blaupunkt THB-210 amp and installing it onto the BOSE sub and using the line inputs as sugested above.
 
A

·
Guest
Joined
·
0 Posts
Which one did you go for in the end?

I'm looking to wire the BOSE sub up without the standard BOSE loom and wire it up manualy.
If thats not viable I'm looking at using a Blaupunkt THB-210 amp and installing it onto the BOSE sub and using the line inputs as sugested above.
Anybody???? :confused:
 

·
AO Silver Member, 155 Lounge Winner 09
Joined
·
7,713 Posts
not sure what you are actually asking here.

the sub will need an amplifier. if you aren't going to use the Blaupunkt amp, what other amp would you use? the Bose system has a Bose amplifier - you don't have this though, do you?

:)
 
A

·
Guest
Joined
·
0 Posts
not sure what you are actually asking here.

the sub will need an amplifier. if you aren't going to use the Blaupunkt amp, what other amp would you use? the Bose system has a Bose amplifier - you don't have this though, do you?

:)
My appologies - I'll start again!

I have a non BOSE seup in my car. I have sourced a BOSE sub. I'm thinking there is probably no way of connecting the existing BOSE amp up to my system without the loom? Besides the Amp isn't all that anyway as disables the EQ etc.

So first of all is there anyway I can wire up the standard 937 to the BOSE sub,
OR (most preferable)
Use a Blaupunkt after market amp or similar make that will except high speaker inputs and drive purely the sub and let the 937 power the door speakers as per normal????

I was also toying with the idea of purchasing the Blaupunkt THB 210A sub and stripping out the amp and bolting it to where the BOSE amp currently is. The reason for doing it this way is the HU is still powering the door speakers whilst the sub amp purely powers the sub meaning easy plug n play wiring effectively.

Also my HU only has one live pin in the yellow MINI ISO socket - is this normal? From what I heard all 937 CD units are BOSE compatible?
 

·
AO Silver Member, 155 Lounge Winner 09
Joined
·
7,713 Posts
So first of all is there anyway I can wire up the standard 937 to the BOSE sub
no, a headunit (virtually any headunit) does not have enough power to properly run a subwoofer. also, the factory headunit does not have a 'lowpass crossover filter'. a LPF takes away the higher frequencies, and allows only the subbass frequencies to pass to the sub. an amplifier will have a LPF.

OR (most preferable)
Use a Blaupunkt after market amp or similar make that will except high speaker inputs and drive purely the sub and let the 937 power the door speakers as per normal????
this is quite do-able, and fairly common approach. you need to tap into the speakerwires for the audio signal, and direct this to an amplifier that runs the sub.

I was also toying with the idea of purchasing the Blaupunkt THB 210A sub and stripping out the amp and bolting it to where the BOSE amp currently is. The reason for doing it this way is the HU is still powering the door speakers whilst the sub amp purely powers the sub meaning easy plug n play wiring effectively.
as above, you can use 'any' amp to do this. probably best to buy 'just an amp' and not rip apart that 'active sub'.

what is involved, is tapping into the speakerwires. this signal has been amplified by the headunit, so is commonly refered to as a 'high level' signal. you then need to reduce the signal level down to 'low level' (the equivalent of being unamplified). this is achieved with an LOC (line output converter, aka line level converter or hi-lo converter). connect this to the speakerwires, and it will reduce the signal level. then connect your amplifier to the LOC.

some amplifiers have inbuilt LOCs (aka high level inputs or speakerwire inputs). this is even simpler. the amplifier can be connected directly to the speakerwires.

the headunit can continue to run the door speakers. only a tiny amount of the signal is tapped off by the LOC; not enough to noticably reduce the volume of the speakers.

Also my HU only has one live pin in the yellow MINI ISO socket - is this normal? From what I heard all 937 CD units are BOSE compatible?
that is normal. it is used to trigger an amplifier on/off. you will find that amplifiers require a +12V trigger to turn them on, so the yellow socket output can provide this. (some amplifiers, when you use the high level inputs, have auto sensing, and will turn on/off automatically when it detects an audio signal feeding into it).

if you are going to use the Bose subwoofer, you need to confirm what impedence (ohm) it is. seek advice from a specialist ICE store if you are unsure (take the sub to them to check). i think the Bose sub is dual voicecoil, with each VC being 4ohm (ie: DVC dual 4ohm). so this can be wired to be 2ohm overall (VCs wired together in parallel); you would then need an amplifier that is capable of running a 2ohm load and offer suitable power. a monoblock (1-channel) amp would suit in this situation. this may be above your understanding (sorry, i've no idea what you do/don't know); this is where you need to rely on a good ICE specialist to help out.

:)
 
1 - 12 of 12 Posts
Top