Hey guys. Just got my first 350z (05 35th anniversary) and need to replace the head unit to get Bluetooth. I found a good deal on a Sony XAV-AX1000 (https://www.crutchfield.ca/p_158XAV1...AV-AX1000.html) and bought it. I would love to install it myself as the cost at a shop is around $150. The problem is that I have no idea how any of this type of stuff works. I’ve done my fair share of research, but still can’t figure out the amplifier issue. The Sony head unit says it has a built-in amp, but from my research the Bose system in my car has 2 amps already(one for the sub and the one under the antennae in the trunk area). Is it a problem if I install a head unit with an amp into my system that already has amps? Do I need to bypass one of the stock amps? Any info would be very helpful.

 

Welcome and congratz.
You have several options.
1) Use the og wiring to connect your new head unit to amps and speakers. Not recommended as you'll likely have a lot of "gain" noise.
2) Bypass the external amp and wiring and run all new speaker wire. Really doable in an afternoon. Make sure to get color coded wire with a stripe (polarity) and crimp style butt connectors. The og speakers are 2 ohm and generally considered the weakest link but it won't be a problem. Just follow the wiring diagram from your kit/website, you should be fine. Also ck on YT for DIY vids. Gl!

 

Thanks for the help. What exactly is “gain” noise? I’m assuming rewiring the whole system will be a lot more work than just replacing the head unit, so is having a bit of “Gain” noise fine? Thanks again.

 

This noise sounds like a constant "hissing" sound which is more audible/annoying at lower volume levels. It's caused when you amplify an already amplified signal. Most modern amps have gain adjustments to minimize this noise, but since the amp was designed in conjunction with the Bose head unit I kinda doubt this one has it, dunno.
I've prolly hard wired 6-8 cars over time. If you have concerns I'd suggest you connect to the stock Nissan harness, see if it sounds OK to you. In and out in an hour.

The amp you referred to around the antenna is strictly there to improve the radio signal before it goes to the head unit, so more to improve quality of radio listening rather than volume.

 

Ok thanks again for the help. When it comes in I will just connect it to the stock system and see if there is any gain noise, and if there is i guess i'll rewire it all without the amp for the sub.

 

My question is.....is the circle around the z on the fender bronze?

 

No offense, OP, but it sounds like you don't have a lot of starting knowledge when it comes to audio. That's ok! Everyone starts out not knowing much (or anything for that matter). I'll try to highlight a few concepts that may help you out. This is just going to be the basics. Also, if you purchased your head unit through Crutchfield, they are very helpful if you have wiring questions.

You mentioned that your new receiver has a built-in amplifier. Yes - almost ALL receivers have a built-in amplifier. Your OEM unit has a built-in amplifier also. The amplifier is the unit responsible for sending and boosting the audio signal to your speakers. The head unit you are purchasing has an amplifier rated at 55w x 4 (peak power) and 20w RMS x 4. I won't get into specifics, but RMS is what you are looking for as it is the continuous power rating (or Root Mean Square). Different speakers have different capabilities so you don't want to under-power or overpower your speakers. The "x 4" means that it has 4 channels to send the audio signal to 4 speakers. Typically, this is 2 front speakers for the left and right, and 2 rear speakers, also left and right.

Also, related to wattage and power ratings, the RMS rating of 20w x 4, is at 4 ohms. The standard for most aftermarket systems (in cars) is 4 ohms. Ohm is the measure of resistance between two electrical points or impedance. A lower ohm rating will have lower resistance and therefore, the signal will be easier to conduct and the speakers will drive easier. A higher ohm rating will mean there is more dampening power and you will need more wattage to power your speakers to get the same results. I won't get into ohms and audio quality, etc.

The OEM Bose system runs off of a proprietary system that operates at a lower impedance (I believe 2 ohms), but I think they are wired in parallel which changes their impedance to 1 ohm. Don't worry about what any of this means, but for your purposes, this means that you cannot simply hook up the wiring harness from your head unit to the OEM wiring and expect it to sound good. You will need a signal processor to step down the 4 ohm output from your receiver to the built-in Bose system. You will need something like the PAC ROEM NIS-2 in order to accomplish this. You can make small adjustments per channel on the ROEM NIS-2 for the output signal by turning the small adjustment screws. The audio output signal from your receiver will go through the ROEM NIS-2 and feed your stock amplifier the proper signal to then send to your OEM speakers.

The amplifier for the radio signal needs to be connected to the remote wire on your receiver to power on. The remote wire sends a 12v+ signal whenever it is powered on. In order for the receiver to receive the proper AM/FM radio signal, the signal needs to be boosted or amplified.

As to your other question of bypassing the OEM Bose amps - yes. This is possible. A lot have chosen to do this since they feel the Bose (or Blose) system is junk. To do this, you won't need the PAC unit, but you will need AT LEAST one additional amplifier. For example, you can get a 5 channel amplifier and wire it to the RCA outputs on your new receiver and send the signals to the 2 front speakers, 2 rear speakers, and subwoofer. Or, you can get 2 amplifiers: one that is 2 channel for the front, and one that is 2 + 1 mono for the rear speakers and the subwoofer. Alternatively, you can get three amplifiers, a 2 channel for the fronts, a 2 channel for the rears, and a 1 channel for the subwoofer. The Sony receiver has preamp RCA outputs for the front, rear, and subwoofer, so there are many different setups. It all comes down to your budget and main goals.

As to the question about gain... Gain is a way to increase the power on your amplifier to the speakers that you are driving. While a higher gain means more power, do NOT turn the gain all the way up thinking this is best. Gain is a way to fine tune the audio signal without causing distortion. Best practice is to turn your music up to the appropriate listening level with the gain at maybe 1/4 setting. Then, gradually increase the gain until you start to hear distortion. At that point, decrease the gain until there is no more distortion and the signal is clear. In essence, the previously mentioned PAC unit coupled with the OEM Bose system alters the gain of the audio output level to your speakers by making adjustments in order to avoid distortion.

TLDR:
Easiest (and cheapest) way to install an aftermarket head unit into an existing Bose system is to use the PAC ROEM NIS-2. Plenty of write-ups on this site on how to do this. Happy to help if I have thoroughly confused you or you have any other questions! Good luck!

 

Yes you are right this is really the first audio project for me, but i hope to learn more about it and do a whole new system when i have the money.

i did order through crutchfield, and they put a few things in my cart that they thought would be helpful for installation. i ordered them all because they were like 90% off, and im wondering if i can work with those instead of having to buy the PAC ROEM NIS-2.
Wiring Harness(https://www.crutchfield.ca/p_1207075...g-Harness.html)
Line Output Converter?(https://www.crutchfield.ca/p_142SLC4...Converter.html)

i searched the PAC on crutchfield and it looks to me like the replacement for the wiring harness, and it also says it doesn't fit my car. Are you sure that it will fit?

Thanks for all the info on everything else. Very, very helpful!

 

From the links you sent the Sony has 5 pre-amp outs so you won't need the Scosche box. The Metra harness isn't a good match bc it only accounts for 4 channels, but no subwoofer. I can't say whether the pre-amp out for the sub is incorporated into the main harness or separate.
I wouldn't start this project before finding out, Crutchfield should be able to advise you.

 

Ok thanks. I am going to wait until i get all the stuff in before i order the PAC or do anything else. I may have more questions once i get the unit in but your information is greatly appreciated.

 

Sometimes the description for the compatibility chart of the PAC unit is wrong. I can assure you that it works. I have an '05 w/ Bose and it works flawlessly. With that said, yes, the configuration that Crutchfield sent you should also work since it includes the Scoshe line out converter (LOC). But, I'm not really sure where the placement of the Scosche converter comes into play. I guess you run RCA cables from your receiver to the Scoshe and then another set to the Metra harness. It seems to me like that is the hard way of doing things.

If you use the PAC, instead of using the Metra 70-7551 with the Scosche LOC, you will need to use the Metra 70-7550. My preference would be to use the ROEM NIS-2 and the Metra 70-7550 because it frees up the RCA outputs on the back of your receiver in case you decide to add extra amplifiers later. The ROEM NIS-2 utilizes the feed from the speaker wire outputs of your receiver instead of the RCA outputs.

With regard to JHC's comment, you may get by without using the Scosche LOC as long as you can adjust the gain of your RCA outputs to a low enough level to avoid distortion. IIRC I believe you will still be able to have the subwoofer because the Bose amplifier behind your seat gets its audio signal from the rear outputs (in a stock wiring configuration), so you don't need an additional line.

 

Thanks for the additional input, Heel! I recently moved and was running around my garage looking for my old Bose unit. Glad you clarified that !

 

So plug the Metra harness into the new receiver and plug the PAC ROEM NIS-2 into the input in the car and then solder the wires in the middle? Is that the correct way to do it?

 

I ordered a head unit from Crutchfield and I believe the converter arrived already wired for me. It also came with installation instructions specific to the 350z. It will make more sense when you can look at the wiring harness and the instructions. Plus their tech support is awesome.

 

Correct. If you use the Metra 70-7550 and the PAC, you connect the Metra wiring harness to the wiring harness of your new head unit. The wires for your speakers from the Metra will then be soldered to the PAC and then the output from the PAC will be soldered to the Z's factory speaker wires. Be sure to note that the PAC has connections for both "high level (+)" and "low level (+)" for each channel (shown in 'A Cable' below). Use the high level for your (+) connections and disregard/tape off the low level (+) connections.

 

This is also true. Crutchfield offers a service (I think for like an additional $20) for everything to come prewired and connected.