[andredequeiroz]

Billfitz

I installed the Hi-Fi front speakers (speakers + tweeters) and the sound quality improved INCREDIBLY well.
If I had known it would improve so much, I don't think I would have even installed the slim subwoofer under the front passenger seat. (I only installed the subwoofer because the car already had this harness from the previous owner).

But there are still some doubts:
I already read somewhere here on the forum that "Rear speakers are high-passed in all BMW systems. There is no bass signal in there."
Regarding the installation of the rear Hi-Fi speakers, do I MUST have to install the tweeters in the doors for the impedance adjustment issue or can I leave it with just the Hi-Fi speakers (without tweeters) (I don't care about the tweeters at the rear as I'm at the most time alone in the car). I'm afraid of using only speakers without tweeters and this could cause problems with the stereo due to the lack of parallel connections between the rear speakers + tweeters.

I have a 10" nakamichi subwoofer module, which captures the signal through the original subwoofer harness. Is it ok to keep it there?? What kind of issue of impedances of the complete set when using this subwoofer module in parallel with the set? Ideally, would I remove this slim subwoofer??

Remembering that I will use the VIBE amplifier (it hasn't arrived for me yet).
Can I use this slim subwoofer together with the VIBE + Hi-Fi speakers??

In advance, thank you!

[Billfitz]

All of the door midrange speakers are high passed by one method or another. I thought I already covered the impedance issue.

[andredequeiroz]

Originally Posted by Billfitz

All of the door midrange speakers are high passed by one method or another.

I didn't get this lesson about the two methods of bypass.

Originally Posted by Billfitz

I thought I already covered the impedance issue.

The existence of the nakamishi subwoofer slim getting the front signal from the subwoofer doesn't transform/interfere at the front equivalente impedance?

Can I/should I use this slim subwoofer together with the VIBE + Hi-Fi speakers and 8" subwoofers?? What do you recommend?

[Billfitz]

Impedance is only an issue when you have two or more speakers wired in parallel. If you have 8" woofers under both seats I don't see the need for another sub. If for whatever reason you use one it should be on its own amp channel. As for the highpass, not bypass, the base system runs the same signal to the underseats and front door midranges, high passing the midranges with in line capacitors. The rear door midranges are electronically high passed in the head unit.

[andredequeiroz]

Thank you so much!! It was very clarifying.

Originally Posted by Billfitz

If for whatever reason you use one it should be on its own amp channel.

The last one: what do you mean about its own amp channel?
Based on your explanations, I think I will remove the nakamichi then.

[Billfitz]

It's own amp channel means just that, no other speaker is using the same amp channel.

[andredequeiroz]

Originally Posted by Billfitz

It's own amp channel means just that, no other speaker is using the same amp channel.

This is the device that I have:

NAKAMICHI NBF25.0A
SPECIFICATIONS
N-Power: 150W
Peak Power: 1000W
Distortion (THD): ＜0.5%
Signal To Noise Ratio: ＞90dB
Frequency Response: 20Hz-180Hz
Input Sensitivity, High Level: 1.0V
Input Sensitivity, Low Level: 300mV
Low Pass Filter: 50Hz-180Hz
Bass Boost: 0 to -12dB
Fuse Rating: 25A
Subwoofer: 10 inch, 4 ohm
Unit Dimension: 300x225x72mm

This is how I connected it. I used the High Level inputs (from the OEM subwoofer wiring)


Doesn't the fact that I'm getting the high signal from the OEM subwoofer wires cause my nakamichi slim subwoofer to enter the impedance count, interfering with the final result?
The nakamichi has its own amplifier module, but what about the issue of picking up the signal on the wire that reaches the OEM subwoofers?

The fact that the nakamichi is getting this high signal interferes at how the base system sees the hole setup?

I'm sorry. My english is not good. But I hope that now I have managed to explain my concerns better.

[Billfitz]

It's self powered, so it's on its own amp channel. The input is high impedance, so it does not affect the load on the primary amp.

[andredequeiroz]

Billfitz

I read somewhere here on the forum that, when installing 8" speakers without the use of amplifiers, the sound quality drops a lot. It seems that the original system can't play everything correctly (I think you said that yourself somewhere else).

So now I'm looking forward as ever for the VIBE amp to arrive and improve the sound. (while I had the original 6.5" sub, the sound was AMAZING! Just installing the 8" subs made all the speakers significantly worse, even the door ones).

I hope the VIBE amp fixes everything again.

[Billfitz]

Installing 8" underseats in place of 6.5" would have little effect, and could not degrade the performance of the door speakers. The reason why going from 6.5" to 8" without adding an amp is a waste of time and money is that the amplification provided by the head unit alone can't exceed the capabilities of the 6.5", so there's nothing to be gained in doing so.

[andredequeiroz]

Billfitz
Here I am again.

I send this message do the Vibe support:
I bought a POWERBOX65.4BMW3: OPTISOUND BMW PLUG AND PLAY AMPLIFIER UPGRADE for my BMW F30 2015. My car has a stock stereo system (no OEM amp). Haven't installed the module yet, because it didn't arrive.

Here in Brazil, I bought all the 4 door mid speakers of the Hi-Fi system from a junkyard, the Hi-Fi subwoofers (8 inches) and the front door tweeters.
When I upgraded the stock speakers and the tweeters, but still using the 6.5" OEM subwoofers, the sound of my car was AMAZING. Very strong and precise.
But when I installed the 8" subwoofers (2 ohms, of the BMW Hi-Fi systems), the sound got worse. Its not strong anymore.. and it looks like it's crippling, distorting.
My question is: when I install my vibe amp, can I use the 8" underseat woofers (2 ohms), or this amplifier works only with the stock 6.5" subwoofers (4 ohms)??

And they reply:
Your issue is the 2 ohm subwoofers. You have asked to much from the amplifier. We recommend the use of 4 ohm subs only.

And:
If you add the 2 ohm speakers you do have the option to use another amp like the POWERBOX400.1M-V7 and power these separately.


Should I remove the 8" subs and reinstall the 6.5" stock subwoofers??

I can't believe that even when I install their amp I will have to use the stock underseat subwoofers

[Billfitz]

The Hi-Fi woofer nominal impedance is closer to 3 ohms, and in the 50-120Hz range averages 5 ohms, so that's not a problem.