Bang and Olufsen (B&O) Subwoofer / Amplifier Add-On DIY

[diegom305]

Well there's not many wires that need to be run...your battery is in the back, you can pick up a ground on the left side of the trunk, if you have a B8 the whole red fuse row is switchable for your remote and just add two taps to the factory sub wires to a LOC. Will only take 20min max and can be removed and factory amp connected back at anytime.

Mine is B8.5 any good recommendations for a small monoblock amp.. And sorry but I don't know what a LOC is. So if you can give me some pointers that could be good too. Thx

[dizzlesizzle]

Not 100% but the B8.5 doesn't have the switchable 12v in the trunk like the B8, you would have to run a wire from the drives side fuse box unfortunately. With that said, there are plenty of amps on the market that don't require a remote wire for on/off operations. They use the audio signal for sensing when to power on/off the amp. I would look for one of those. A LOC is a line out converter, its able to take the higher voltage signal from the factory amp to sub and drop it down to a RCA low-pass output. Here is a link to the one i bought which works great. http://www.amazon.com/LC2i-Audiocont.../dp/B004CTBYGE

[diegom305]

Not 100% but the B8.5 doesn't have the switchable 12v in the trunk like the B8, you would have to run a wire from the drives side fuse box unfortunately. With that said, there are plenty of amps on the market that don't require a remote wire for on/off operations. They use the audio signal for sensing when to power on/off the amp. I would look for one of those. A LOC is a line out converter, its able to take the higher voltage signal from the factory amp to sub and drop it down to a RCA low-pass output. Here is a link to the one i bought which works great. http://www.amazon.com/LC2i-Audiocont.../dp/B004CTBYGE

Thx. Gonna start looking for more info. Videos of your car on amp and sub? Overall sound? Waay better or just better?

[diegom305]

I found this.

This could be very helpful for all of us just wanting to swap the sub.

no need to do it only for a 8ohm one, we can use a dual coil 4 ohm and connect it like this. THis will show the amp like there is 1 8ohm connected

[jackp311]

For those of you just wanting to upgrade the sub and not put in an amp, I definitely advise against it. Any sub that is of a decent quality will likely be able to handle much more power than the one you are replacing. Bearing that in mind, it's probably going to take MORE power than the amp can provide to really get it playing. That being said, if you insist on doing something freeair like the factory sub, get a sub with a QTS of .6 or more.

[diegom305]

For those of you just wanting to upgrade the sub and not put in an amp, I definitely advise against it. Any sub that is of a decent quality will likely be able to handle much more power than the one you are replacing. Bearing that in mind, it's probably going to take MORE power than the amp can provide to really get it playing. That being said, if you insist on doing something freeair like the factory sub, get a sub with a QTS of .6 or more.

Can you point me to few models.? I have no idea what is qts. I really don't want to mess with wiring so I think just swapping the sub will kick better than the oem b&o in my car

[MVR 155]

Can you point me to few models.? I have no idea what is qts. I really don't want to mess with wiring so I think just swapping the sub will kick better than the oem b&o in my car

Qts for someone who is not into this kind of stuff is completely greek. You will need a sub with adequate free air capability. What he told you is correct in terms of just adding a sub with no amp..... it will likely sound worse as the factory B&O amp is not going to drive an aftermarket subwoofer...... This is the biggest mistake that amateurs attempting to upgrade audio make. If you don't want to mess with wiring take your car to a trusted shop and have them do the install. If you have basic automotive/wiring knowledge putting a sub into one of these cars is a breeze. There are plenty of step by step write ups to effectively do this on your own providing you possess the basic knowledge. Not trying to give you a hard time but being truthful is going to save you time, headaches and $$$$$

I can tell you that adding a sub and amp to the factory B&O will completely transform the sound system in this car. If you honestly want the best sound then I would suggest removing the sub from the rear package tray/panel all together, the rear panel lacks the integrity and is known to fluctuate badly in these cars. Free air setups typically lack the accuracy of a sealed enclosure. A sealed enclosure in the trunk will yield the best sound and with all of the small enclosure subs currently available you don't have to sacrifice hardly anything in the way of trunk space. Removal of the B&O enclosure makes a great "pass through" into the car so the new sub in the trunk can do it's work. Grabbing the signal for the amp (that will power the sub) is very easily accessed at the plug from the factory B&O sub. The battery is in the trunk so there are no wires to run through the cabin/firewall/under hood. Im running an Alpine SWE-12S4 (12" 4ohm sub with a 250W RMS rating) in a ATrend B Box Pro that has a volume of .88 cubic feet. The sub is rated for a .65-1.0 cubic foot box so this is a great match. Powering the sub is a Kicker 500.1 mono amp which has a 275w RMS rating at 4ohms.... this is slightly over what the sub is rated at RMS but I have the gain down pretty low along with a remote knob in the cabin which I do not go full tilt with. This set up sounds absolutely amazing. Best of all the price for everything was under $400. I already had the LOC, wiring kit/fuse block and RCA's so figure up to another $100 for that stuff..... still has you under $500 for everything. A shop should not charge you more than a couple of hundred to do this type of install so even then your not looking at much coin for the whole thing out the door. I purchased my stuff at a local shop www.abt.com (they are a huge electronics/high end audio store).

[integroid]

For those of you just wanting to upgrade the sub and not put in an amp, I definitely advise against it. Any sub that is of a decent quality will likely be able to handle much more power than the one you are replacing. Bearing that in mind, it's probably going to take MORE power than the amp can provide to really get it playing. That being said, if you insist on doing something freeair like the factory sub, get a sub with a QTS of .6 or more.

Qts for someone who is not into this kind of stuff is completely greek. You will need a sub with adequate free air capability. What he told you is correct in terms of just adding a sub with no amp..... it will likely sound worse as the factory B&O amp is not going to drive an aftermarket subwoofer...... This is the biggest mistake that amateurs attempting to upgrade audio make. If you don't want to mess with wiring take your car to a trusted shop and have them do the install. If you have basic automotive/wiring knowledge putting a sub into one of these cars is a breeze. There are plenty of step by step write ups to effectively do this on your own providing you possess the basic knowledge. Not trying to give you a hard time but being truthful is going to save you time, headaches and $$$$$

I can tell you that adding a sub and amp to the factory B&O will completely transform the sound system in this car. If you honestly want the best sound then I would suggest removing the sub from the rear package tray/panel all together, the rear panel lacks the integrity and is known to fluctuate badly in these cars. Free air setups typically lack the accuracy of a sealed enclosure. A sealed enclosure in the trunk will yield the best sound and with all of the small enclosure subs currently available you don't have to sacrifice hardly anything in the way of trunk space. Removal of the B&O enclosure makes a great "pass through" into the car so the new sub in the trunk can do it's work. Grabbing the signal for the amp (that will power the sub) is very easily accessed at the plug from the factory B&O sub. The battery is in the trunk so there are no wires to run through the cabin/firewall/under hood. Im running an Alpine SWE-12S4 (12" 4ohm sub with a 250W RMS rating) in a ATrend B Box Pro that has a volume of .88 cubic feet. The sub is rated for a .65-1.0 cubic foot box so this is a great match. Powering the sub is a Kicker 500.1 mono amp which has a 275w RMS rating at 4ohms.... this is slightly over what the sub is rated at RMS but I have the gain down pretty low along with a remote knob in the cabin which I do not go full tilt with. This set up sounds absolutely amazing. Best of all the price for everything was under $400. I already had the LOC, wiring kit/fuse block and RCA's so figure up to another $100 for that stuff..... still has you under $500 for everything. A shop should not charge you more than a couple of hundred to do this type of install so even then your not looking at much coin for the whole thing out the door. I purchased my stuff at a local shop www.abt.com (they are a huge electronics/high end audio store).

I am going to have to disagree with the two of you. I replaced my factory sub with a Kicker 10" sub in the factory location and ran it on the stock amp for a few weeks before my amp came in. It sounded much better than the stock sub. In fairness, I did have a few layers of sound deadening and a 4 ohm sub (OMGWTFBBQ) and no harm was done to the factory amp. For someone that wants a little more low end bass I think it is a perfect mod. I am in the process of trying to figure out a way to get a sealed enclosure as the free air sub with an aftermarket amp is just too boomy and not very crisp.

[MVR 155]

I am going to have to disagree with the two of you. I replaced my factory sub with a Kicker 10" sub in the factory location and ran it on the stock amp for a few weeks before my amp came in. It sounded much better than the stock sub. In fairness, I did have a few layers of sound deadening and a 4 ohm sub (OMGWTFBBQ) and no harm was done to the factory amp. For someone that wants a little more low end bass I think it is a perfect mod. I am in the process of trying to figure out a way to get a sealed enclosure as the free air sub with an aftermarket amp is just too boomy and not very crisp.

]

That is good to know but those results are not typical. Factory speakers are normally very efficient in terms of power handling so they can be driven by amps that don't have a ton of power. After market speakers typically need higher power levels to drive them effectively, running a speaker that is somewhat efficient in a free air setup may be the reason you had OK results, is the sub you purchased specifically designed to operate in a free air enclosure? Do you have the model number/specs for the exact sub your running? Would be good info to post if you got good results from it. Sorry for all the questions but it could definitely help out the guy looking to go this route.

[integroid]

]

That is good to know but those results are not typical. Factory speakers are normally very efficient in terms of power handling so they can be driven by amps that don't have a ton of power. After market speakers typically need higher power levels to drive them effectively, running a speaker that is somewhat efficient in a free air setup may be the reason you had OK results, is the sub you purchased specifically designed to operate in a free air enclosure? Do you have the model number/specs for the exact sub your running? Would be good info to post if you got good results from it. Sorry for all the questions but it could definitely help out the guy looking to go this route.

I think the woofer has been replaced by something else in there line up. Kicker Comp 10c4

Features and Specs
Size 10 -inch
Impedance 4 ohms
Cone Material Injected Polypropylene
Surround Material Ribbed Foam
Ideal Sealed Box Volume (cubic feet) N/A
Ideal Ported Box Volume (cubic feet) N/A
Port diameter (inches) N/A
Port length (inches) N/A
Free-Air Yes
Dual Voice Coil No
Sensitivity 86.2 dB at 1 watt
Frequency Response 30 - 500 Hz
RMS Power Range (Watts) 50-150
Peak Power Handling (Watts) 300
Top Mount Depth (inches) 5
Bottom Mount Depth (inches) N/A
Cutout Diameter or Length (inches) 9 1/8
Vas (liters) 46.94
Fs (Hz) 33
Qts 0.585
Xmax (millimeters) 9.6
Parts Warranty 1 Year
Labor Warranty 1 Year

[gendry]

With the understanding that anyone who wants to "do it right" and get the best performance improvement needs to change the amp driving the sub, can knowledgeable folks chime in here for the best recommendations of "drop in" subs that will be an improvement while being powered under the factory amp.

I would like a little more bass, especially from the lower frequencies, but do not need a really booming system. I am hoping to just swap the sub (knowing this isn't ideal and I can't expect a huge improvement with stock amp) and take it from there. Would appreciate any suggestions of a good speaker to use given the seemingly limited available power.

The kicker comp 10c4 is a starting place...

[integroid]

With the understanding that anyone who wants to "do it right" and get the best performance improvement needs to change the amp driving the sub, can knowledgeable folks chime in here for the best recommendations of "drop in" subs that will be an improvement while being powered under the factory amp.

I would like a little more bass, especially from the lower frequencies, but do not need a really booming system. I am hoping to just swap the sub (knowing this isn't ideal and I can't expect a huge improvement with stock amp) and take it from there. Would appreciate any suggestions of a good speaker to use given the seemingly limited available power.

The kicker comp 10c4 is a starting place...

There was another thread on here that had a different sub listed as well. Might have been an Image Dynamics sub? I know there is also a JL sub that I looked at that would fit the bill as well. I settled on the kicker sub because I got it for $50 on sale at Fry's. I figured if it sounded like poop the most I would be out was $50.

[gendry]

Thanks integroid. I am probably guilty of failing to fully utilize the search button... but I recall past threads that provided a detailed DIY with replacing the AMP which (1) is more than I want to do for starters and (2) wasn't thought to be applicable to the facelift B8.5 models.

[MVR 155]

Thanks integroid. I am probably guilty of failing to fully utilize the search button... but I recall past threads that provided a detailed DIY with replacing the AMP which (1) is more than I want to do for starters and (2) wasn't thought to be applicable to the facelift B8.5 models.

If you plan to move forward and not add any additional/aftermarket amplifier then I would suggest finding an efficient speaker that is able to be used in a free air set up. Keep in mind that adding an amplifier to a B8/B8.5 or just about any other car are virtually the same. I found that adding the amp/sub to my 2013/B8.5 was one of the easiest cars yet. I have additional subs/amps in all of my current vehicles and have had them in countless past vehicles. Honestly if you can take the rear package tray/deck apart, remove the current sub and replace it with a new one Im sure you could handle the additional work of installing the amp. If you have the tools, basic automotive repair knowledge, take your time and ask questions as needed I think you can do it. Like George McFly says: "If you put your mind to it you can accomplish anything" LOL!!!

[gendry]

Fair enough... especially because technically I have a degree in EE ;)

Okay your pep talk is motivating me. Can you share which components you used in your swap? Did you do essentially the same thing as the OP?

[integroid]

If you plan to move forward and not add any additional/aftermarket amplifier then I would suggest finding an efficient speaker that is able to be used in a free air set up. Keep in mind that adding an amplifier to a B8/B8.5 or just about any other car are virtually the same. I found that adding the amp/sub to my 2013/B8.5 was one of the easiest cars yet. I have additional subs/amps in all of my current vehicles and have had them in countless past vehicles. Honestly if you can take the rear package tray/deck apart, remove the current sub and replace it with a new one Im sure you could handle the additional work of installing the amp. If you have the tools, basic automotive repair knowledge, take your time and ask questions as needed I think you can do it. Like George McFly says: "If you put your mind to it you can accomplish anything" LOL!!!

I agree....everything you need is in the trunk and dont really have to run any wires. I think it took me less than an hour but I did use to install car stereos growing up and help pay my way through college.

[MVR 155]

Fair enough... especially because technically I have a degree in EE ;)

Okay your pep talk is motivating me. Can you share which components you used in your swap? Did you do essentially the same thing as the OP?

Im using some different things with the only major difference being the sub/amp itself, the other items like the wire kit/fuse holder and LOC are perfectly good to use. There is also nothing wrong with the sub/amp the OP elected for either. I wanted a larger sub (12") in a sealed enclosure and a more powerful amp. And its not because I needed to make a ton of noise. Getting sound into the cabin from the trunk when you have a well built car with leather seats/sound deadening etc..... is going to take some extra oomph/power. I wanted a sub that could hit low frequency and still be extra tight all while occupying only a small amount of space. If you go up to post #47 you will see a detailed description of my components. Im in no way saying this is the best setup or what has to be used, it just got me exactly what I was looking for. I think I mentioned it in one of my other posts but make sure to remove the stock B&O sub/enclosure as this creates a pass through for the sound to get into the cabin much better.

[diegom305]

I am going to have to disagree with the two of you. I replaced my factory sub with a Kicker 10" sub in the factory location and ran it on the stock amp for a few weeks before my amp came in. It sounded much better than the stock sub. In fairness, I did have a few layers of sound deadening and a 4 ohm sub (OMGWTFBBQ) and no harm was done to the factory amp. For someone that wants a little more low end bass I think it is a perfect mod. I am in the process of trying to figure out a way to get a sealed enclosure as the free air sub with an aftermarket amp is just too boomy and not very crisp.

. Do you recommend me a single 4ohm or dual 4 connected in series to make it 8 ohm. . ? I am not going to add an amp. Just want better result for just swapping the sub

[dizzlesizzle]

I still think your better off just getting a separate amp and sub with small enclosure. All the connections you need are right in the trunk not much wiring to do. You will probably spend more time removing the rear deck, removing the factory sub and layering sound deadening and finding a sub to fit perfectly without modification. My buddy tried this, depending on the speaker you put into the factory sub opening and how powerful it is, regardless of amp, the rear metal deck which holds the sub will flex and make a bunch of noise. Just my opinion.

Here is a link showing the flex.
http://www.youtube.com/watch?v=5RnNgQS2IXo

[diegom305]

I need the space in my trunk... Enclosure is not an option for me I think that flex is powered by an amp. I just want a bit of a better kick. What I haven't figured is what is safest and will be better for the sound and the car.... Go with single 4 ohm even though our car amp is 8ohm or get a dual coil 4 ohm and connect it in series to make the sub a 8ohm sub

[diegom305]

I need the space in my trunk... Enclosure is not an option for me I think that flex is powered by an amp. I just want a bit of a better kick. What I haven't figured is what is safest and will be better for the sound and the car.... Go with single 4 ohm even though our car amp is 8ohm or get a dual coil 4 ohm and connect it in series to make the sub a 8ohm sub

Bringing the thread back to life. i did the sub and amp installation. i used the blue yellow and white yellow to get the signal that comes into my amp. got a monoblock with lpf and is active just in case.

HEre is the amp http://www.bossaudio.com/auto/car-au...-audio-r1100m/

Big question here is the input sensitivity.


i have 2 options 100mV-2V or 2-4V what should i select to match the factory HU?

ANy one here had the same issue? or can you take a look into your amp and let me know what should i choose?


PS: if anyone used a different selection of cables to tap and get the input signal to the amp let me know.

[mike.powers]

Hmm - didn't think of it like that - I'm not an electrical engineer. Maybe someone who is can chime in...? I went back and looked at the pics to see if I could see any boxes. I do remember seeing more than one wire coming off the positive battery post. So, there are definitely some items that are not put through that box if there is one on my car.

Electrical Engineer here. I can tell you that your friend was correct about Audi having circuitry to measure the current draw on the battery, but wrong about where you should connect. There is a shunt between the ground of the battery and the wire that connects to the frame of the car that has an ammeter attached. If you connect directly to the battery post then the system cannot monitor the draw. So the standard configuration of grounding to the frame is the right way to do it to allow the system to measure the extra current draw properly.

[jayts]

Electrical Engineer here. I can tell you that your friend was correct about Audi having circuitry to measure the current draw on the battery, but wrong about where you should connect. There is a shunt between the ground of the battery and the wire that connects to the frame of the car that has an ammeter attached. If you connect directly to the battery post then the system cannot monitor the draw. So the standard configuration of grounding to the frame is the right way to do it to allow the system to measure the extra current draw properly.

Good timing Im about to do a full system install and was going to go directly to the battery with positive and negative, so instead I hook the negative up after the shunt or directly to the frame where the battery negative attaches I assume

[phanker]

Any thoughts on the Pioneer-TS-SWX251?
Looking for something really small. Thanks.

[jazza08]

I've put sound deadening in my car and I am quite happy with the bass levels but I am interested to know has anyone simply replaced the factory amp with a better one keeping everything else the same?
I think the car could use a little extra volume providing I don't go over the RMS of the speakers (which I don't know if they're already maxed out?).

[Dirty Jersey]

This thread was very helpful upgrading my sub.

[jayts]

This thread was very helpful upgrading my sub.

Nice install, where you ground the amps?

[UmbroVR6]

whats the story with that enclosure? custom made? or stealth box? that install looks sick.

[doug97gxe]

I won't requote the pictures but...

- did you have to relocate the BO Unit for that enclosure?
- where did you patch into the factory system? the BO wires? or directly into the existing sub wires
- where did you get the enclosure

[MVR 155]

I won't requote the pictures but...

- did you have to relocate the BO Unit for that enclosure?
- where did you patch into the factory system? the BO wires? or directly into the existing sub wires
- where did you get the enclosure

Not my system but I can see that he relocated the factory amp as well as the new amp to the bottom of the package tray. Using a LOC (line out converter) you can tap the wires into the factory subwoofer and that box looks to definitely be a custom made enclosure. Only thing I would suggest to Dirty Jersey is to remove the factory B&O sub itself...... it will sound much better as the new sub will cause the B&O sub (if it's still hooked up) to be inaccurate along with not allowing for the air of the new sub to pass into the cabin of the car. I initially tried to use my new sub with the B&O hooked up, without it hooked up and completely removed....... completely removed made a world of difference.

[doug97gxe]

Not my system but I can see that he relocated the factory amp as well as the new amp to the bottom of the package tray. Using a LOC (line out converter) you can tap the wires into the factory subwoofer and that box looks to definitely be a custom made enclosure. Only thing I would suggest to Dirty Jersey is to remove the factory B&O sub itself...... it will sound much better as the new sub will cause the B&O sub (if it's still hooked up) to be inaccurate along with not allowing for the air of the new sub to pass into the cabin of the car. I initially tried to use my new sub with the B&O hooked up, without it hooked up and completely removed....... completely removed made a world of difference.

ok thanks... i just bought an ID Max 10 and getting ready to head to my installer

[mr shickadance]

Not my system but I can see that he relocated the factory amp as well as the new amp to the bottom of the package tray. Using a LOC (line out converter) you can tap the wires into the factory subwoofer and that box looks to definitely be a custom made enclosure. Only thing I would suggest to Dirty Jersey is to remove the factory B&O sub itself...... it will sound much better as the new sub will cause the B&O sub (if it's still hooked up) to be inaccurate along with not allowing for the air of the new sub to pass into the cabin of the car. I initially tried to use my new sub with the B&O hooked up, without it hooked up and completely removed....... completely removed made a world of difference.

the JL Amp he is running has a built-in LO converter that would work well enough to be used.

everything else you said is spot on.

your installer has to the tools and knowledge to figure out if the line going into the BO amp is high or low and can go from there also.

[MVR 155]

the JL Amp he is running has a built-in LO converter that would work well enough to be used.

everything else you said is spot on.

your installer has to the tools and knowledge to figure out if the line going into the BO amp is high or low and can go from there also.

I know that some amps have the built in LOC...... wasn't sure if that one did so I mentioned the LOC to the guy making the inquiry.

[QuattroRocket]

Now all we need is a source for that enclosure !!!

[mr shickadance]

that enclosure is a custom fiberglass one, any local car audio place that doesn't rhyme with est-buy will be able to do it. Expect to pay about 4-5 for it

[doug97gxe]

no its not fiberglass .. its mdf

[mr shickadance]

true, your right, didn;t look at the pictures close enough hah

[Hatchman]

Any one have the dimensions for the amp? Looking for one that will just "snap in" to the space below the B&O amp.

Thanks for the help!

[DatBigDude]

Will be using this when i decide to tackle audio, thanks for the writeup!

[Pawan2013]

Qts for someone who is not into this kind of stuff is completely greek. You will need a sub with adequate free air capability. What he told you is correct in terms of just adding a sub with no amp..... it will likely sound worse as the factory B&O amp is not going to drive an aftermarket subwoofer...... This is the biggest mistake that amateurs attempting to upgrade audio make. If you don't want to mess with wiring take your car to a trusted shop and have them do the install. If you have basic automotive/wiring knowledge putting a sub into one of these cars is a breeze. There are plenty of step by step write ups to effectively do this on your own providing you possess the basic knowledge. Not trying to give you a hard time but being truthful is going to save you time, headaches and $$$$$

I can tell you that adding a sub and amp to the factory B&O will completely transform the sound system in this car. If you honestly want the best sound then I would suggest removing the sub from the rear package tray/panel all together, the rear panel lacks the integrity and is known to fluctuate badly in these cars. Free air setups typically lack the accuracy of a sealed enclosure. A sealed enclosure in the trunk will yield the best sound and with all of the small enclosure subs currently available you don't have to sacrifice hardly anything in the way of trunk space. Removal of the B&O enclosure makes a great "pass through" into the car so the new sub in the trunk can do it's work. Grabbing the signal for the amp (that will power the sub) is very easily accessed at the plug from the factory B&O sub. The battery is in the trunk so there are no wires to run through the cabin/firewall/under hood. Im running an Alpine SWE-12S4 (12" 4ohm sub with a 250W RMS rating) in a ATrend B Box Pro that has a volume of .88 cubic feet. The sub is rated for a .65-1.0 cubic foot box so this is a great match. Powering the sub is a Kicker 500.1 mono amp which has a 275w RMS rating at 4ohms.... this is slightly over what the sub is rated at RMS but I have the gain down pretty low along with a remote knob in the cabin which I do not go full tilt with. This set up sounds absolutely amazing. Best of all the price for everything was under $400. I already had the LOC, wiring kit/fuse block and RCA's so figure up to another $100 for that stuff..... still has you under $500 for everything. A shop should not charge you more than a couple of hundred to do this type of install so even then your not looking at much coin for the whole thing out the door. I purchased my stuff at a local shop www.abt.com (they are a huge electronics/high end audio store).

Sorry for posting on an old thread but I am looking to do this now also. My question is what if the frequency range of the stock sub because if you tap into its signal then I assume that will also be the frequency range of your aftermarket sub. I am afraid that its range does not go very low to get those really low bass notes that I love. Does your setup hit the low notes hard? Thank you.