Going for a full Bosectomy - SUCCESS! (custom speaker/amp/DSP install)

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DeudeMann

Active member
Joined
Jun 20, 2017
Messages
32
Location
South Texas
So I am revising this thread to make it less of a questions asked and more of a here is what I am doing post.

Right now I am gathering all of the components that I need for a complete Bosectomy of the stock Bose stereo that came with my 2015 Nissan Leaf. The Bose system is OK, but certainly not great, and I know from past stereo installations I have done before that it can sound MUCH better without spending lots of money.

Here are the plans for the system:

- Subwoofer build already completed, details here:
http://www.mynissanleaf.com/viewtopic.php?f=36&t=24187

- I am going to use the stock head unit so I can retain all of the stock functionality. The Bose amplifier will not be used at all.

- For signal processing (active crossovers, parametric EQ, time alignment, etc.) I am going to use a MiniDSP C-DSP 6x8. This is a great unit for the price and is well regarded in the car audio forums. It also has differential inputs so the output of the stock head unit can be connected directly to the C-DSP. It has six inputs so I will even be able to retain the fader if I chose to.
https://www.minidsp.com/products/car-audio-dsp/c-dsp-6x8

- For the front door speakers I will be installing Tang Band W6-1139SIF 6.5" woofers to use as midbass speakers, from ~80Hz to ~250Hz.
For those not familiar with Tang Band, they make lots of drivers for DIY speaker builds, including some very nice stuff on the smaller end of the woofer scale. This little beast has a low Q for infinite baffle installation (in a door) and 11.5mm of xmax, all for $50.
https://www.parts-express.com/tang-band-w6-1139sif-6-1-2-paper-cone-subwoofer-speaker--264-919

- For the upper front speakers, I am going to mount some 3.5" coax drivers in pods at the a-pillars. Right now I plan on using Pioneer TS-A878 speakers.
https://www.amazon.com/Pioneer-TS-A878-Inch-2-Way-Speakers/dp/B00009QOTA

- The subwoofer amplifier is one of these, a Power Akoustic Class-D monoblock which is a little beast that fits in a small space.
https://www.amazon.com/Power-Acoust...&sr=1-2&keywords=power+acoustic+monoblock+amp

- The door speakers and a-pillar pods will be powered by a Precision Power 900.4 which is a Class-D 4-channel amplifier, which also fits in a small space.
https://www.amazon.com/Precision-Power-P900-4-4-Channel-Amplifier/dp/B005KVEPVO

Subwoofer build, about $60 in speakers and $60-$80 in building supplies
Door speakers, about $100
A-pillar speakers, about $50
Front stage amp, about $170
Subwoofer amp, about $105.
Stiffening capacitor, about $35.
Misc. wires, connectors, fuse blocks, what nots, about $50.

So, that comes to about $650 in parts, well under $1000, which I would therefore call a 'budget' build. And though most everyone here will not be able to hear it in person, believe me, it is going to sound really, really good when it is built and tuned.

The basic layout is this:
- Stock HU outputs (LF, RF) will be input directly into the C-DSP 6x8, which has differential inputs.
- Stock HU outputs (LR, RR) will be run directly to the rear door speakers, bypassing the Bose amp.
- The C-DSP 6x8 will have five outputs: FL door, FR door, FL a-pillar, FR a-pillar, subwoofer.
- The four front speaker line outputs from the DSP will go into the 4-channel amplifier, then the outputs are wired to each speaker set.
- The subwoofer line outout will be routed to the monoblock amp and then wired directly to the subwoofer.
 
So I found a little more information on the Bose amplifier. It looks like it is located in the right rear hatchback area behind one of the panels. The part number is 280603NF0A. Using that number i found some images of the amplifier, including the connectors:

https://goo.gl/photos/9oJLMWRoRAkLY3qC7

Due to the number of connectors it looks like this is for all of the speakers in the system. This is potentially very useful since if there is a straightforward way to connect the inputs into the Bose amp into a standard aftermarket amp, then the amp could be placed in the trunk region, the door speakers could be replaced with something more standard, and BAM, bye-bye Bose.

It is my understanding that there is nothing different about the Nissan head unit for the Bose system, and that the amp and the speakers are the real differences.
 
I have not replaced any of the Bose components in my 2016 Nissan Leaf SL, but I am looking into it. I found wiring diagrams and more information for a 2014 Leaf with Bose on this site: http://www.nicoclub.com/manuals/Leaf/2014 Leaf/av.pdf.

and yes, apparently the head unit sends front and rear left and right pre-amp signals to the Bose amplifier in the right rear cargo area. The Bose amp and processor sends high, mid and low frequencies to the front and rear speakers, high signals to the tweeters and low frequencies to the subwoofer.

Choices are to take low frequencies from Bose amp to a replacement powered subwoofer and leave the rest alone. Or use the pre-amp signals from the head unit and replace the Bose amp with aftermarket amplification and signal processing. Install the speakers of your choice.

But I don't want to spend 3 grand. Wah! :cry:
 
Oh man thanks for linking to that PDF! I tried to grab that off of the nismo site last week and could not get to it for some strange reason.

So it is all right there in that PDF, pages AV-387 through AV-389. It shows the four inputs into the Bose amp (LF, RF, LR, RR) and where they are on the connector. So, that solves that problem of how to connect in pre-amp.

From what I have been reading, the inputs into the Bose amp are differential balanced inputs, so they are a bit different than a standard unbalanced line out (like the typical RCA) or a high-level out. It seems that the best way to deal with this is to use something like an AudioControl DQ-61 ( http://www.audiocontrol.com/car-audio/factory-system-upgrade/dq-61/ ) which can accept differential balanced inputs. Then, the output from that is sent via standard RCA unbalanced outputs to whatever amp combo you want to use. The Bose amp would be bypassed completely, and with it, all of the Bose equalization and base limiting behavior.

The nice thing about the AudioControl DQ-61 is that it also includes 14 bands of equalization, and time alignment, all for less than $300 if you shop around. So, conceivably, it would be possible to build a very decent system for less than $1000. The DQ-61 is not remotely adjustable, but controlled by dials on the box. This is a good or bad thing depending on your perspective.
 
The Audio Control DQ-61 should work well if you use the front and rear, left and right pre-amp outputs from the head unit. You should be able to tap them from the inputs on the Bose amp. The Bose amp has 7 channels of output which is one more than the DQ-61 accepts. Alternatively, you could go with the JL Audio Fix 86 with 8 inputs. List price is $20 less than the DQ-61, but street price is rarely discounted. They both have similar features, but equalization on the Fix 86 is done via your PC or laptop.

I'm still on the fence. I'm not a Bose basher wanting to tout my expertise in sound. I do appreciate quality reproduction of the soundstage and have built award winning systems back in the day. Bose Audio for autos are good for mass market better than standard audio sound. Still, I sometimes cringe when the mids come through muddy or the bass booms on a favorite song. A powered sub would solve some of the problem, but those front speakers have to go too. The only compatible 2-ohm component replacement speakers I found were Focal ES 165K2 for about a grand. For that money, you could buy a five channel amplifier, replace all speakers including the subwoofer and the DQ-61 or Fix 86... but then there's installation. I'm a senior citizen. I'm not crawling around in the car to install a sound system. So I have to figure another $500 for installation.

The Bose system is starting to sound better. :?
 
I've been heavily researching DSP units since I have not shopped for them in a long time. The ones I really want that have 8 channels (like you mentioned) are $500 and up, more than I really want to spend.

Though... It looks like the TWK-88 might be a better option than the Fix since input corrections are not needed pre-Bose-amp. Much more processing power on the output side.

Or maybe even better... Gets good reviews.
https://www.minidsp.com/products/car-audio-dsp/c-dsp-6x8


There are some other 2-ohm speakers out there with good efficiency, like the Infinity Kappas or the JBLs I am going to install in the front doors/a-pillars within the next few days. I'll report in on how they do with the Bose amp since that is how I will be running them for starters.
 
I'm really hating on you, now DeudeMann. You just couldn't let sleeping dogs lie, could you. Now I can't stop thinking about upgrading my Leaf Bose audio. This is going to cost me a couple grand, I'm so very sure. Here's my wishlist:

1. Focal BombA BP20 Powered Subwoofer - I already test fitted. Perfect for Bose sub replacement. Bandpass with 150-watt amp... should be enough thump.
2. JL Audio FiX 86 Sound processor. Automatic time alignment, channel summing, and equalization with 10-channel graphic EQ on front and rear channels
3. JL Audio JX 400/4D 4-channel ammplifier - 70 RMS x 4
4. Focal RSE-165 Auditor Series 6 3/4" component speakers front
5. Focal RCX-165 Audior Series 6 3/4" 2-way speakers
6. Dynamat
7. Installation because I am now a senior citizen who won't crawl around in my car.

I could get off easy for about $1500, but more likely, it will be closer to $2G.


Thanks a lot, DeudeMann. :x
 
The fault dear Brutus lies not in our forums, but in ourselves. :D

I already have the amp and speakers I need, so if I forego the rear door speakers for now, all I need is the DSP. It would be a relatively cheap upgrade that would have a huge impact on the SQ.

So why get the JL Fix and not the JL Twk? From what I have read if you tap into the stock system pre-Bose amp, there is nothing to correct, so the Twk is a better option. The Fix from what I can tell only corrects the inputs and is more appropriate if you are using it post-Bose amp. You would still need a Twk (or some other DSP) to get all of the output tuning required to get the system dialed-in on EQ and TA (delay).
 
I think you're right DeudeMann. For processing, TwK88 would be the best option. I am anxious to see your results. I believe that much of my issues with my sound system could be corrected with sound deadening. I get too much unclear midbass vibration from the front speaker area on many songs. I just didn't want to tear down everything to install Dynamat and have to do it over again to install new speakers.
 
So I have ordered the C-DSP 6X8 processor and am working on something different for the above dash speakers (front sound stage). More details coming once I have some more work completed.
 
For now I am only going to run five channels:
LR bass in doors
LR midrange/tweeters in a-pillars
Subwoofer in hatch
With good time alignment, the imaging will be as good or better than it would be with a center channel, albeit only for one person at a time. Since 99% of the time I am the only person in the car when commuting, and am the audiophile of the family, that is OK with me.
 
Here is the 4-channel amplifier and the C-DSP 6x8 installed on the mounting plate. This will be placed in a hidden spot in the car.
https://photos.app.goo.gl/bvkaoV9mJvHimzx73
 
More progress today... So I had heard about how cheaply made the Bose drivers were, and after seeing them for myself, yeah, they are pretty cheap. Plastic baskets (not always bad, but not impressed with these), really thin paper cone, very thin rubber surround, small voice coil, puny magnets.... I am happy to see them go.

They are good for one thing however, The basket can be gutted, and used to mount the Tang Bands, or I imagine most any other 6.5" speaker. With only a pair of wire cutters (a.k.a. dikes) one can remove most of the basket, the cone, and magnet assembly, leaving only the circular portion of the basket that bolts to the door panel. Epoxy the basket to the back of the new speaker's mounting flange, and viola, you have a nice, clean mount for your new speakers. In the case of the Tang Bands, they needed to be spaced away from the door since they have a much greater mounting depth than the Bose drivers.

Here is the Bose basket after removal of the cone, surround, magnet, spider, wire leads, and connector. It has been placed onto the back of the Tang Band's mounting flange.
https://photos.app.goo.gl/ojsV9H1d2MDpDGGx2

Here is a close up of the epoxy used to glue the Bose basket to the Tang Band's mounting flange. I taped the Tang Band screw holes to hold in the epoxy, roughed both surfaces with 200 grit sandpaper, pre-coated both mating surfaces with epoxy, assembled them, then ran another bead around the outside perimeter of the joint. The plate is used to support the Tang Band by the flange. I suppose you could set it down on its surround, but I do not recommend that.
https://photos.app.goo.gl/7Ep42JiU4zUoc94g1
 
More progress over the weekend. I have removed the Bose door speakers from both front doors, salvaged their frames for reuse (as noted previously), epoxied them to the Tang Bands, added sound damping material to both doors, and installed the new drivers. Everything went smoothly. Here is the passenger door with the new speaker in place.

https://photos.app.goo.gl/4aul5i9WKAYfFxdf1
https://photos.app.goo.gl/OY26LIly0jaEDwLG2

Even though the back of the Tang Band is much larger and deeper than the Bose speaker, the forward offset from reusing the Bose mount lets the speaker drop right in. Also, it still matches up with the 'tunnel' protrusion on the back of the door panel.
 
Note that I have cut out the plastic vapor barrier and covered all of the holes in the door panel with the soundproofing material. This isolates the back wave of the speaker from the cab and provides some significant sound damping. In the areas where the holes in the door panel are large, I doubled up the thickness of the soundproofing material. The material is the typical peel-and-stick stuff consisting of a rubberized mat bonded with a layer of aluminum. It is Noico 80mm available from Amazon. I'm happy with it, and the price is reasonable compared to the name-brand stuff. It does not have an odor at all from what I can tell, is clean to work with (no mess), and cuts easily with a utility knife.

A quick tip... Notice in the pictures that I trimmed out the clear plastic vapor barrier up to where the black goo is used to hold it to the door, rather than removing the plastic completely. That goo is very, very messy stuff, so I chose to just leave it there, covered up by the left-over plastic, rather than remove it. This is a big time saver.

Another quick tip... Some of the youtube Leaf door removal videos show that the door handle section can be unscrewed from the door panel. That works, but it is a lot easier IMO to just disconnect the actuator cables. They are easy to remove and reattach. Overall the door panel assembly is a breeze to remove, much easier than others I have messed with.

So the stereo still works, but the door speakers are way down on output as expected due to their higher impedance (4 Ohms). For now I'm using the rear doors to fill in the sound until I wire in the new DSP, amp, and dash pods.
 
Thank you again for your detailed posts. I was wondering whether you were going to use the head unit outputs (Front L+R and Rear L+R.) The Nissan Leaf AV docs show that the AV unit for the non-Bose with Navigation is part number JSNIA3618ZZ and has a 45 watt x 4 amp built in. Curiously, the AV unit for the Bose with Navigation is identical. This would mean that the pre-amp inputs on the Bose amp are actually speaker level outputs.

Have you tested them yet?

I am still in the planning stages for upgrading my Leaf. I'm leaning toward using the Bose amp to power the rear speakers. I would take the front pre-amp signals from the head unit and route to a Focal DSA500RT Powered Subwoofer with a built-in 2 x 65 watt amp for front speakers. The unit includes a DSP with an EQ and time alignment functions. I like this idea because I would be adding only one piece of equipment other than replacing the front speakers.
:?:
 
No I have not tested the outputs yet, but if they are speaker level outputs AND differential signals that is good for noise immunity.

That integrated Focal setup is nice. I had not seen that one before. You won't be able to independently time align the front speakers (door versus a-pillar) but you will be able to time align the sub which will help bring it forward. I like your idea of using the Bose amp, or even the head unit for that matter, to power the rear door speakers.

The next big step is to tear into the trunk panels to get to the Bose amp. I also need to finish installing the dash speaker pods.
 
Another update - SUCCESS!!! The Bose amp is out of the car completely and everything is running from the head unit and the DSP/amps I added.

Some details:
- The output from the STOCK head unit (originally connected to the Bose amp) works great as the input into the DSP. I am using the two front channels (front-left, front-right) as the signal to the DSP, which I am sure could also be used as high-level inputs straight into an aftermarket amplifier.
- I ran the rear outputs from the STOCK head unit directly to the rear door speakers for backfill. It works, but the output is very weak. If I decide to do anything more with them, I'll probably add another two-channel amp for those.
- I tapped into the stock wiring at the Bose amplifier by cutting off the Bose connectors and splicing in my own wiring harnesses with Molex connectors. I used two 16-pin Molex sets, which sounds like a lot, but a lot are required. Just for the audio, at the Bose amp, there are four pairs of input wires, and six pairs of output wires for a total of 20 connections.
- In the factory service manual I found that there is a remote amp turn-on wire for the Bose amplifier. So I tapped into that and am using it to power on the DSP and the two amplifiers. Works great. So there is no need to run a separate remote amp wire.
- I have not installed my dash pods yet so for now I am using the Bose a-pillar tweeters in the front. I believe I have them crossed over at 5 KHz. They are working well enough for now. The plan is to disconnect the tweeters and use those wires to power the dash pods.
- The Tang Band front door speakers are TREMENDOUSLY better than the Bose speakers. No comparison. Very natural sounding output on vocals, bass guitar, toms, whatever. I am very happy with these little guys.

So all I have done so far is set the crossover points on the DSP and the whole thing sounds much, much better than the Bose system. Once I add the time alignment and euqalization (Room EQ Wizard, reference mic, etc.) it is going to sound really, really good. I'm very pleased with how it is going so far.

FYI - You do NOT have to remove the rear seat or completely remove the right hatch trim panel to get to the Bose amp and the connectors. The panel is flexible enough to bend out of the way and get to everything. This ended up being easier than I expected.

Tapping into the stock harness is just a matter of cutting off the existing connectors, and splicing your wiring into the cut ends. It is time consuming, and took about 3 hours to complete. This included double-checking that I had the right input and output wires. There are a lot of connections to make, so it is best to write out a wiring list in advance, and use color coded wires whenever possible. The stock wire colors as indexed by the service manual are a little weird, like several different shades of blue that can easily be confused, so be sure to check colors against the pin outs on the stock Bose amp connectors (the ones that are cut off). Also, use a small speaker to check the output wires from the HU, and use a small AAA battery to check the connections to the speakers; if you tap the two wires you are connecting to each terminal of the battery (just tap, don't hold the connection), you will hear a small pop from the door speaker you are wiring. This does not work well with the a-pillar tweeters, so check those with an audio signal.

Here are some pictures of the Bose amp removal, the wiring harness splicing, and the finished harness with the panels back in place:
https://goo.gl/photos/GPR1tewxBVkw2cqJA
https://goo.gl/photos/jZoHX9Yi8xCoztj6A
https://goo.gl/photos/XpV3fzfJN9bFhrtT6

Here is a picture of the subwoofer box with the amplifiers, the DSP unit, capacitor, and the mating Molex connectors:
https://goo.gl/photos/AfeCtyeUiixxHEnK9
 
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