The definitive stereo and subwoofer upgrade thread

[04lss]

im considering getting me a small powered subwoofer, like a 10 inch, or running one of the 300wrms amps i have sitting around. With the battery being in the trunk wiring should be easy, i was planning on pulling off the subwoofer for a signal. All im really looking for is to fill out the bottom end and take a bit of work off the door speakers. Any reason i shouldnt take this approach?

[wrxkyle]

i would first try the jl 10w0 in the stock location. you may like it, if not enough then yeah throwing your 300 watt amp on it is fine, just be aware that you'll use less than 300w as it is open air, you'll want to tune and use the gain knob to limit power based on xmax instead.

with a little modding the ib10au will fit, you just have to use tin snips to open some little channels for the "legs" of the basket to go through.

or there are 10" and 12" boxes that fit in the drivertrunk cubby and passenger trunk cubby.
https://www.ebay.com/itm/AUDI-A4-B8-...8AAOSwO6haksxT

the driver side cubby one is just made out of cnc'd mdf not fiberglass so might be able to find cheaper but will have to relocate amps if you have them there.

[Fresh.S4]

pulled from that facebook page. this is all the info you need to mount and power a subwoofer.


speaker1.jpg

[wrxkyle]

^^^take that info with a grain of salt, you can NOT safely go a little over subs rms when doing an infinite baffle install, you will damage the sub suspension from over travel near guaranteed, you actually should target roughly 50% rms wattage when doing a no-box install. if you're installing a traditional sub in a box then you might get away with it. still you should turn down a larger amp to hit rms which i think they touched on. just know that without a box you can't run full power, which isn't a problem, the sub will be louder with less power as all the power is going to moving the cabin air, not fighting the air in the box. sub will also hit lower and smoother.

I'd also be hesitant to use shallow subs for that application, as those normally are built for low airspace installs and not suitable for infinite baffle (no box)

i have an idq10 mounted from the trunk side, and while it's a 500 watt sub i'm hitting xmax at more like 250 watts. if i tried to feed it 500 i'd be bottoming out the coil and causing damage to the suspension over time.

[Yukoncole]

Update - The Polk Audio DB1042DVC has proven to be a nice upgrade! I did though buy other speakers and want to test, so this weekend I removed the Polk and installed the best-spec'ed speaker I could find. It is shallow, infinite baffle, has a 92db sensitivity, and is not power-hungry at 200W RMS and is Dual 4ohm Voice coil so can be wired at *ohm all meaning it should play well with the factory B&O Amp. It was though not even close to as easy to install as the Polk which just dropped right in!

This Belva Sub required me to get a 3/4 inch wood spacer, sand down the internal diameter of the ring to fir the speaker, drilling holes in the ring to match the speaker, trimming the ring to fit the rear deck, trimming the rear dash cover, and trimming the speaker cover...all shown in the pictures attached here! You will also need to remove the grill of the speaker which is easy, with just 4 screws!

In all that being said, it does fit better in regards to trunk space as it is so shallow and does seem to be a marginally better sound than the Polk, but not a huge difference.

If you want an easy install with a noticeable bass increase...do the Polk. I will sell you the one I installed with everything you will need to install it, except tools of course....PM me. If you want the best bang for the buck and are not afraid of and capable of some extra work, see the link below and my pics attached.

You can find this speaker on Amazon, you will need a 3/4" wood spacer ring (I have 2 left if you need one), some small bolts, washers, and nuts, plus obviously a little speaker wire.

https://www.belvaproducts.com/marine...-bmss10rw.html

InkedInkedIMG_9742_LI.jpgInkedIMG_9741_LI.jpgInkedIMG_9745_LI.jpgInkedIMG_9744_LI.jpgIMG_9743.jpg

[wrxkyle]

Update - The Polk Audio DB1042DVC has proven to be a nice upgrade! I did though buy other speakers and want to test, so this weekend I removed the Polk and installed the best-spec'ed speaker I could find. It is shallow, infinite baffle, has a 92db sensitivity, and is not power-hungry at 200W RMS and is Dual 4ohm Voice coil so can be wired at *ohm all meaning it should play well with the factory B&O Amp. It was though not even close to as easy to install as the Polk which just dropped right in!

This Belva Sub required me to get a 3/4 inch wood spacer, sand down the internal diameter of the ring to fir the speaker, drilling holes in the ring to match the speaker, trimming the ring to fit the rear deck, trimming the rear dash cover, and trimming the speaker cover...all shown in the pictures attached here! You will also need to remove the grill of the speaker which is easy, with just 4 screws!

In all that being said, it does fit better in regards to trunk space as it is so shallow and does seem to be a marginally better sound than the Polk, but not a huge difference.

If you want an easy install with a noticeable bass increase...do the Polk. I will sell you the one I installed with everything you will need to install it, except tools of course....PM me. If you want the best bang for the buck and are not afraid of and capable of some extra work, see the link below and my pics attached.

You can find this speaker on Amazon, you will need a 3/4" wood spacer ring (I have 2 left if you need one), some small bolts, washers, and nuts, plus obviously a little speaker wire.

https://www.belvaproducts.com/marine...-bmss10rw.html

InkedInkedIMG_9742_LI.jpgInkedIMG_9741_LI.jpgInkedIMG_9745_LI.jpgInkedIMG_9744_LI.jpgIMG_9743.jpg

thanks for this info, i was looking at the polks but not sure on the fitment, my solution was like yours much more difficult as i had to mount the idq10 from below in the trunk, it has a much wider cutout diameter than almost all other 10" subs on the market. also makes fitting it in prebuilt boxes/rings very difficult, have to recut the holes. sounds great though.

[Yukoncole]

thanks for this info, i was looking at the polks but not sure on the fitment, my solution was like yours much more difficult as i had to mount the idq10 from below in the trunk, it has a much wider cutout diameter than almost all other 10" subs on the market. also makes fitting it in prebuilt boxes/rings very difficult, have to recut the holes. sounds great though.

You can see my earlier post which shows the Polk install, it fits like a dream and surely offers a upgrade in bass.


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[Cooper993]

Update - The Polk Audio DB1042DVC has proven to be a nice upgrade! I did though buy other speakers and want to test, so this weekend I removed the Polk and installed the best-spec'ed speaker I could find. It is shallow, infinite baffle, has a 92db sensitivity, and is not power-hungry at 200W RMS and is Dual 4ohm Voice coil so can be wired at *ohm all meaning it should play well with the factory B&O Amp. It was though not even close to as easy to install as the Polk which just dropped right in!

This Belva Sub required me to get a 3/4 inch wood spacer, sand down the internal diameter of the ring to fir the speaker, drilling holes in the ring to match the speaker, trimming the ring to fit the rear deck, trimming the rear dash cover, and trimming the speaker cover...all shown in the pictures attached here! You will also need to remove the grill of the speaker which is easy, with just 4 screws!

In all that being said, it does fit better in regards to trunk space as it is so shallow and does seem to be a marginally better sound than the Polk, but not a huge difference.

If you want an easy install with a noticeable bass increase...do the Polk. I will sell you the one I installed with everything you will need to install it, except tools of course....PM me. If you want the best bang for the buck and are not afraid of and capable of some extra work, see the link below and my pics attached.

You can find this speaker on Amazon, you will need a 3/4" wood spacer ring (I have 2 left if you need one), some small bolts, washers, and nuts, plus obviously a little speaker wire.

https://www.belvaproducts.com/marine...-bmss10rw.html

InkedInkedIMG_9742_LI.jpgInkedIMG_9741_LI.jpgInkedIMG_9745_LI.jpgInkedIMG_9744_LI.jpgIMG_9743.jpg

How low (inches) does the sub hang below the deck lid?

The links shows some type of cover. Was that easy to remove?

[Yukoncole]

How low (inches) does the sub hang below the deck lid?

The links shows some type of cover. Was that easy to remove?

I mention the grill removal in my post, it comes off with just 4 screws.

I just measured it at only 1 and 3/4 inches below the deck hole opening.


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[04lss]

How much RMS power does the factory amp route to the sub. Im not against just using the factory amp to power an 8 ohm sub in a ported box for maximum efficiency. ALso easily removable when i take the car to the track.

[Yukoncole]

How much RMS power does the factory amp route to the sub. Im not against just using the factory amp to power an 8 ohm sub in a ported box for maximum efficiency. ALso easily removable when i take the car to the track.

I have never seen a definitive answer on this, sorry.

[wrxkyle]

How much RMS power does the factory amp route to the sub. Im not against just using the factory amp to power an 8 ohm sub in a ported box for maximum efficiency. ALso easily removable when i take the car to the track.

would be cool if someone could take theirs to a shop that has an smd or amp dyno and find out. you can run a 4 ohm sub on the b&o amp even though the oem is 8 ohms. i've tested personally and it worked fine and was a little louder as well which is to be expected. i fade almost all the way front so the rears aren't getting much power anyway, so not worried about burning out the amp imput side power supply, and if the sub circuit took a crap well i have a dsp going in anyway. but it worked just fine and others have done the same. it will get a hair more volume and will reach a bit deeper. a 12 in a side cubby box with a proper amp and tuning will obviously be way way better though.

[04lss]

Well i pulled the rear deck cover off, regardless of what i do subwoofer wise, i want/need to throw some MLV on the sheet metal and probably some sound insulation foam towards the rear to help prevent any rattles. I think while im doing that, ill splice some speaker wire into the feed for the sub.

[Yukoncole]

Well i pulled the rear deck cover off, regardless of what i do subwoofer wise, i want/need to throw some MLV on the sheet metal and probably some sound insulation foam towards the rear to help prevent any rattles. I think while im doing that, ill splice some speaker wire into the feed for the sub.

I used moving blankets and stuffed them in before clipping the front down and through the tweeter holes into the sides. If you want the Polk or the Belva….hit me up, I will sell you either one.


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[Fresh.S4]

I used moving blankets and stuffed them in before clipping the front down and through the tweeter holes into the sides. If you want the Polk or the Belva….hit me up, I will sell you either one.


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i used old baby fleece blankets. rolled one up tight long ways and used it as a ring around the sub. and the other i made a chubby stubby roll and stuffed it on the blank side.

[04lss]

I used moving blankets and stuffed them in before clipping the front down and through the tweeter holes into the sides. If you want the Polk or the Belva….hit me up, I will sell you either one.


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Will either of them fit without an adapter bracket in the factory location? I have no realistic way to make the ring as i live in an apt.

[Yukoncole]

Will either of them fit without an adapter bracket in the factory location? I have no realistic way to make the ring as i live in an apt.

I will sell you either one with everything you would need! The Polk with no ring/spacer or the Belva with the already trimmed ring/spacer plus all the hardware and wire/connectors you will need for either one.


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[Yukoncole]

Will either of them fit without an adapter bracket in the factory location? I have no realistic way to make the ring as i live in an apt.

The Polk is ready to go! The Belva I would have to remove and would need a few weeks.


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[vsaudi]

Has anyone added cooling fans to drivers side rear cubby where old amp was? Have B9RS5 with B&O.

It seems air flows in through cover and down and out through vent. Leaving upper portion too hot in summer.

NavTV Zen unit shuts off when too hot.


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[Fresh.S4]

Will either of them fit without an adapter bracket in the factory location? I have no realistic way to make the ring as i live in an apt.

I bought my 10" ring off Amazon..

[robb1887]

Who's everyone going through to get their Audison equipment? Therese a few references of a specific source. Can someone PM me the info?

Bueller?

Local "Authorized" dealer wants $300 which puts me above Hertz MP70.3 Mille Pros from Crutchfield. The Audison Voce 3's have a better sensitivity though so would be more ideal for the stock amp I'm currently running until I dive for full replacement. There are quite a few European offerings on fleaBay for the Voce but want to ensure they are authentic and as mentioned a few on here have dealt with one seller specifically with good results.

[CardFan]

Bueller?

Local "Authorized" dealer wants $300 which puts me above Hertz MP70.3 Mille Pros from Crutchfield. The Audison Voce 3's have a better sensitivity though so would be more ideal for the stock amp I'm currently running until I dive for full replacement. There are quite a few European offerings on fleaBay for the Voce but want to ensure they are authentic and as mentioned a few on here have dealt with one seller specifically with good results.

It was in 2018 but I got my Voce 3s from this seller on eBay.

https://www.ebay.com/usr/schillaci*it?ul_noapp=true

https://www.ebay.com/itm/263609552241

[Avant17]

Yay I can post!..So I am new here but have lurked for some time. First I wanna say thanks for all that posted on this thread because there is a lot of valuable information that took time for posters to document...so thank you....Second, I wanna say as of yesterday I read through almost all of the 37 pages!!...I don't expect an award or anything, but I just had to mention it...

So I am adding to this post because I need a little more opinion related to what I am about to purchase...

I have a B8 Avant with the B&0. I am half way through adding a lot of sound deadening to the doors and trunk area. I want to change out some of the speakers. I will not be changing out the amp nor do I plan on changing it in the future. After reading through the forum I have decided to purchase the following-

Prima AP8's for the front doors
Voce 3.0's for the dash corner mids
Center dash speaker replacement unknown?

If I had a sedan I would totally be changing out the factory sub, but with the Wagon there are not many options that I know of. I am hoping the AP8's add some more low end while the dash mids put back whatever the AP's end up taking away. I would like to change the rear door speakers, basically because they are just weak. I would like to add a good quality mid to the rear doors that is sensitive enough to operate with the factory amp. I am not sure of any good options for the rear doors that work with the factory B&O amp.

So, if anyone has any suggestions for rear door speakers and/or even anything that would work as a sub replacement for the Avant please let me know. I see there are self powered subs out there but if I went that route I would only want to put it on either side of the hatch, not sure if there are any simple sub systems for that location.

My dash and front door speaker replacements I mention are pretty minor and seem to have been successful in the past, but if there are better options I'm all ears. On a side note, I recently did a similar replacement in my 991.2 Carrera GTS that has the factory BOSE system; Prima AP8's and Voce 3.0's in the doors, 991.2 B&O tweeters in the dash, Hertz center dash speaker. This with a fair amount of door sound deadening really woke up the system. Sounds really good now. I am hoping to get similar benefits in my wagon. Anyway, thanks for any suggestions in advance...

PS....Anyone know of a way to upgrade/change/update the MMI screen in the B8? Maybe the only way is a complete MMI upgrade but I'm not sure if that is too complicated for my mostly limited "plug and play" abilities....

[wrxkyle]

Yay I can post!..So I am new here but have lurked for some time. First I wanna say thanks for all that posted on this thread because there is a lot of valuable information that took time for posters to document...so thank you....Second, I wanna say as of yesterday I read through almost all of the 37 pages!!...I don't expect an award or anything, but I just had to mention it...

So I am adding to this post because I need a little more opinion related to what I am about to purchase...

I have a B8 Avant with the B&0. I am half way through adding a lot of sound deadening to the doors and trunk area. I want to change out some of the speakers. I will not be changing out the amp nor do I plan on changing it in the future. After reading through the forum I have decided to purchase the following-

Prima AP8's for the front doors
Voce 3.0's for the dash corner mids
Center dash speaker replacement unknown?

If I had a sedan I would totally be changing out the factory sub, but with the Wagon there are not many options that I know of. I am hoping the AP8's add some more low end while the dash mids put back whatever the AP's end up taking away. I would like to change the rear door speakers, basically because they are just weak. I would like to add a good quality mid to the rear doors that is sensitive enough to operate with the factory amp. I am not sure of any good options for the rear doors that work with the factory B&O amp.

So, if anyone has any suggestions for rear door speakers and/or even anything that would work as a sub replacement for the Avant please let me know. I see there are self powered subs out there but if I went that route I would only want to put it on either side of the hatch, not sure if there are any simple sub systems for that location.

My dash and front door speaker replacements I mention are pretty minor and seem to have been successful in the past, but if there are better options I'm all ears. On a side note, I recently did a similar replacement in my 991.2 Carrera GTS that has the factory BOSE system; Prima AP8's and Voce 3.0's in the doors, 991.2 B&O tweeters in the dash, Hertz center dash speaker. This with a fair amount of door sound deadening really woke up the system. Sounds really good now. I am hoping to get similar benefits in my wagon. Anyway, thanks for any suggestions in advance...

PS....Anyone know of a way to upgrade/change/update the MMI screen in the B8? Maybe the only way is a complete MMI upgrade but I'm not sure if that is too complicated for my mostly limited "plug and play" abilities....

i would do the mille 70.3 pro's, or the 700.3 legends, and not the voce. with no dsp the voce are not a great fit due to the null (dip) they create since they roll off around 300hz and the crossover for the car is 250hz so there's a 50hz gap and it is very noticeable. the mille's aren't THAT much more expensive though.

if you get a passive crossover you could do the tweeters too, or go down the rabbit hole and go with an active front stage, then the voce would sound really good.

one thing is for certain, the mids will roll off higher in frequency than the oem b&o which have a pretty low frequency rolloff (and suffer on the high end) again if your front's aren't blown i'd keep the b&o midbasses until you are going to amp and dsp the front speakers, they really aren't bad. best factory mids i've ever heard, in my limited experience.

if your b&o front mids are not blown then i don't think you'll get a ton of benefit from ap8's. i have some w800neo's i'm going to run amped with dsp but i bought em a year ago and still haven't gotten up the gusto to install them yet but i'll let you know how they turn out. rgsound.it is a great place to order a lot of the euro audio stuff way cheaper, and you can email them to request they remove vat (euro sales tax) from the quote since they don't have to charge it when exporting. got my dsp and w800neo's from them for a song of a price. very well packed, double packed and double bagged and sealed.
https://www.rgsound.it/av-3-0-midran...-id-10190.html
https://www.rgsound.it/ap-8_audison-id-22124.html
https://www.rgsound.it/mp-70-3-midra...-id-26934.html mille pro 3" speakers, by the charts the best match from hertz/audison (same company)
i went with the legends which sound great but are more expensive. , but they still don't keep up with oem for the gutsy guitar like from the intro to todo cambio (best example of the sound you lose, the deep gutsy/crunchy guitar) https://www.youtube.com/watch?v=gO8-9OWzPOQ
https://www.rgsound.it/ml-700-3-lege...-id-23840.html
https://www.rgsound.it/mlk-700-3-leg...-id-23854.html (this one is the tweeter, mid, and crossover, so very good deal for the price.

https://www.ebay.com/itm/152922025336 stealth 10" sub box for the avant

they are Italians and the site is in Italian and google translate works pretty well, but i wouldn't come at them with a "why don't you speak English attitude by any means" ;)

[Avant17]

Man that's some great stuff to look into!...Thanks!...I like that 10" sub box idea a lot....and I'm sure they speak better English than I do Italian...I'll take a look at those mille pro's as an option as well. This is the first time I heard them being mentioned. I really want to try and stay away from changing the amp since I'll be doing whatever handy work is needed and even at 49, wiring is not something I have ever done much of....Thanks again for the information!

[wrxkyle]

Man that's some great stuff to look into!...Thanks!...I like that 10" sub box idea a lot....and I'm sure they speak better English than I do Italian...I'll take a look at those mille pro's as an option as well. This is the first time I heard them being mentioned. I really want to try and stay away from changing the amp since I'll be doing whatever handy work is needed and even at 49, wiring is not something I have ever done much of....Thanks again for the information!

they have the mille pro crossover for 50 euros as well and you could do the mille pro tweeters with those and have a very nice front stage.
https://www.rgsound.it/mpcx-2-tm-3-c...-id-26948.html 50
https://www.rgsound.it/ricerca.html?...=&key=+MP+25.3 89
https://www.rgsound.it/mp-70-3-midra...-id-26934.html 129
268 euros = 315 us


count on like $50ish for shipping but that will likely be offset largely by getting the vat removed.
could end up needing to pay an import tax, depending on how/if customs decides to check it. not sure on that process.

[Tweakophyte]

Get some DynoMat or Stinger RoadKill Matting, I did mine on the bottom and topside, two of the below were the perfect amount.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

How much do you need for the rear deck?

Thx,

[gledy2]

Hi looking for some wiring help. Going to install a hidden box with a Rockford goa gate dual 2 ohm sub with a vibe micro mono amp into my b8 avant with b and o, factory subways missing due to air ride components in the spare wheel well. The main Issue so far has been finding space, after removing the amp, tuner and nav dvd rack, and finding space for all the units along with the box and amp in the same space, but think I’ve managed now!

My two questions are about inputs to the amp.
1) should I use a line output converter or just use the amps high level inputs? Read cases for each, but unsure if the factory sub high level will get a limited signal because of the factory crossover or not? And if I use a loc, will I loose the mmi control over bass levels as compared to speaker level inputs?

2) About running a mono amp and sub. Is it better to use front speaker wires (full range I think) or the existing sub plug as the input for either loc or high level in the amp? Again will the mmi let me control bass levels through the aftermarket amp by adjusting it on screen if I choose the sub plug as my input?

[wrxkyle]

i'll give this one a shot:

Hi looking for some wiring help. Going to install a hidden box with a Rockford goa gate dual 2 ohm sub with a vibe micro mono amp into my b8 avant with b and o, factory subways missing due to air ride components in the spare wheel well. The main Issue so far has been finding space, after removing the amp, tuner and nav dvd rack, and finding space for all the units along with the box and amp in the same space, but think I’ve managed now!

My two questions are about inputs to the amp.
1) should I use a line output converter or just use the amps high level inputs? Read cases for each, but unsure if the factory sub high level will get a limited signal because of the factory crossover or not? And if I use a loc, will I loose the mmi control over bass levels as compared to speaker level inputs?

i don't think that our cars have bass rolloff so an lc2i probably isn't needed, some amps can handle direct speaker input and some can't with our cars, a loc is no different than speaker level inputs in regards to the second part of your question, it's still just sending the same signal from the sub out, it's just changing the voltage to be lower and feeding it to your amp over rca's. same eq signal etc. an lc2i can bumb the lower frequencies if you are experiencing rolloff, as well as provide remote level control which could be handy for you depending on use case (via remote level knob)

2) About running a mono amp and sub. Is it better to use front speaker wires (full range I think) or the existing sub plug as the input for either loc or high level in the amp? Again will the mmi let me control bass levels through the aftermarket amp by adjusting it on screen if I choose the sub plug as my input?
i would use the sub plug. depending on your system the front is not full range (b&o) rear is full range on all the systems i think though, but you're still messing with the sub signals when you fade l/r f/r in those cases which is less than ideal. it's not hard to access the sub signal line, just use it it will make life easier most likely.

[Fresh.S4]

i have the subwoofer output wires (coming off oem amp) going straight into my mono amp HI/LO input.

[monatex]

i have the subwoofer output wires (coming off oem amp) going straight into my mono amp HI/LO input.

I just found this thread and am getting ready for my install this weekend, this is my plan, let me know if anything seems amiss:

I have already tapped the wires going to the factory B&O sub, soldered them to some OFC 16 gauge speaker wire and will be using a wire/RCA converter for high-level input into my Alpine S-A60M amp. I thought the blue/yellow was the positive but it seems it is the negative but I don't think that will matter seeing that I am only using that for the signal? Does it matter what is positive or negative when using the RCA high-level input on my amp? Will this work well or should I get an LOC?

The high level input should also trigger the amp to turn on so a separate turn on wire will not be needed, yes? If it is needed I will run a spade connection out of the pink fuse box strip in the passenger compartment.

I have built a rack suspended 4" below the rear deck to mount the amp. I will run the ground to the existing ground over near the passenger side fuse boxes, is this run too long? I tested resistance and got the same reading at that point that I got using the battery ground.

I will run the power wire direct to the battery using the existing posts at the battery with an 80amp strip fuse.

[mia748sp]

Depending on the amp, you can run straight into the rca input with speaker level (no need for a converter). When I was running just a sub amp, I cut an rca and used the "pos" and "neg" for each tied into the factory wires.

Your amp most likely has signal sensing when using speaker level which will negate the need for a remote turn on wire.

Also a suggestion for mounting your amp if it is small enough..... in the left panel there is room under the B&O amp to add an amp on the equipment shelf. I ran a JL Audio XD there for awhile. That also is easier wiring. There are numerous grounds you can use back there.

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[monatex]

Depending on the amp, you can run straight into the rca input with speaker level (no need for a converter). When I was running just a sub amp, I cut an rca and used the "pos" and "neg" for each tied into the factory wires.

Your amp most likely has signal sensing when using speaker level which will negate the need for a remote turn on wire.

Also a suggestion for mounting your amp if it is small enough..... in the left panel there is room under the B&O amp to add an amp on the equipment shelf. I ran a JL Audio XD there for awhile. That also is easier wiring. There are numerous grounds you can use back there.

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Yes, I mean an RCA wire adapter not an LOC, I figured I would wire the positive into both of the wires for the "red" RCA and the negative onto both of the wires for the "white" RCA. There is something directly under my B@O amp already in the drivers side cubby. I have 4 things in there, the amp is on top, something else is below it, then the navigation DVD, then another small module below that near the floor. I don't have any room in there even though my amp is only 8x8x2.

[mia748sp]

You need to run a pos and neg from the sub wire into each RCA, essentially duplicating the input into each RCA, unless the amp has mono input where you only need to run into one input.

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[robb1887]

You need to run a pos and neg from the sub wire into each RCA, essentially duplicating the input into each RCA, unless the amp has mono input where you only need to run into one input.

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This doesn't make sense to me. I don't understand why you would need to duplicate them.

If you're running the input from the factory sub high-level amp output, it will already be getting signal from left and right. I've never tried it but I'd imagine the internal wiring just has the two RCA inputs bridged internally. Running a two-channel RCA from the head unit or two-channel RCA LOC to pull from a left and right speaker is to ensure that any sub frequencies that are split from left to right in the track mix are sent to the sub.

[mia748sp]

You are correct but my comment said unless the amp can run off an input to one RCA only. Some amps require an input to both RCAs to work correctly and some do not. I didn't pull up the spec on his amp to check is why I gave the disclaimer. I should've said "you may need to" instead of "you need to"

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[monatex]

You are correct but my comment said unless the amp can run off an input to one RCA only. Some amps require an input to both RCAs to work correctly and some do not. I didn't pull up the spec on his amp to check is why I gave the disclaimer. I should've said "you may need to" instead of "you need to"

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The Amp has one set of RCA inputs for either high or low. I'm more concerned about the 'phasing' issue to make sure I have them wired correctly. Does it really matter if I have a positive and negative going to each RCA or can the positive sub wire go to one RCA and the negative go to the other?

[Fresh.S4]

you do need to twist both pos together and both neg together. you tap that into the HI/LO. you do NOT need a seperate plug.

yes! you do have to reverse the polarity. you will know right away if this part is wrong because the sub will hit but not THUMP.

start going back a few pages and look for my post. i took a screen shot from a facebook post and it breaks everything down how to wire/ tune.

[monatex]

you do need to twist both pos together and both neg together. you tap that into the HI/LO. you do NOT need a seperate plug.

yes! you do have to reverse the polarity. you will know right away if this part is wrong because the sub will hit but not THUMP.

start going back a few pages and look for my post. i took a screen shot from a facebook post and it breaks everything down how to wire/ tune.

ok, so yeah I saw about wiring the sub wires opposite for phasing so even though the yellow/blue is negative from the B&O I want to make that the positive on my tap wire. So on my tap wires I should still connect the tap positive to BOTH positive leads from the RCA's and the tab negative to BOTH negative leads, correct? I have a 600 RMS amp and 600 RMS sub so using voltmeter I can go up to 34.64 volts on the gain. I still don't know if I should keep the factory sub installed or remove it, thoughts?

I have an S5 so I don't have room for my amp under the B&O amp, there is something else already there, no idea what it is. I have 4 things in that rack already so I bent some 2" aluminum to create some brackets, bolted them to the rear deck and have an MDF shelf suspended about 4" below the rear deck that I will mount the amp to. I'll run the ground over to the fuse box ground on the passenger side, do you think that is too long with 4g OFC wire? I think it will end up being 3-4 feet long to get there.

[Fresh.S4]

i removed the factory sub and replaced it with a shallow 10". again look for my name in the last 5-10 pages. theirs pictures and info for everything done. do not forget to apply some kind of matting on the underside and on top of the rear deck AND a small rag shoved inbetween the rear deck and the fabric cover because that will vibrate. if you are running a box, remove the stock sub as that will act as a natural port and help eliminate excess vibration/ pressure. you can run a ground to the bolt behind the fabric on the left side of the trunk. you can get the 12v obviously from the trunk battery and for a 12v switch, run the wire to the passenger side fuse box. i believe the pink tray is all switched power. again search my name lol, ive got pics.