[Eighthnote]

Hello all, just wanted to give people an option for those (like myself) that thought the rear center speaker lacked a little bottom end and power.

Most replacement speakers that would improve that part of the sound will not fit in the speaker cavity. The magnet and depth of the speaker will not allow a larger speaker.
What I ended up doing was to replace the speaker with one from a guitar amp.

The speaker would not fit flush so I cut out a ring of packing foam and made what amounts to a large thick gasket. (See pic) Sounds great.

Thanks for looking.

 

[UncleDavid]

Hey Eighthnote, since the original 5 inch woofers are not available, what brand is your woofer, size, ohm, change out sub woofer amp ? A lot of questions in a string.

 

[UncleDavid]

Forgot to mention I have a 1999 Z3 M Roadster with HK speakers

 

[Eighthnote]

I bought this from Parts Express. The part number is 290-023. The model number is C16LU20-51F
It is a Pioneer Speaker. 8 ohms. 6 1/2 " which explains having to find a way to mount it. The magnet on the back is huge for this size speaker. That's a good thing. These speakers were not expensive at all. About 40 dollars? Can't remember.
I did not modify or change out the amplifier located in the trunk. I have change everything else. All speakers and the terrible stock CD/radio are gone. If there's anything else I can provide you just shoot me a message.
Cheers..........

 

[Eighthnote]

I do not want to insult anyone's intelligence but there are quite a few people that hook their speakers wrong and contribute to not getting a sound they want. A speaker when charged is designed so the cone expands out. NOT IN. If your speakers or your wires are not identified being positive and negative there are 2 things you can do to figure that out. One is simply hook the wires up and if you see the diaphragm suck in you have it hooked up backwards. This is called being out of phase and simply reverse the wires. If you know which wire is which but your speaker terminals are not labeled simply place a 9V battery to the terminals. If you have the pos/neg backwards turn the battery around and the diaphragm will behave as it should. Speakers will work if they are hooked up out of phase but they certainly will not sound as well.

 

[UncleDavid]

HK Sub woofer Speakers

I did find a speaker repair shop that can rebuild the existing speakers I have. The cones will be paper.

I am shipping them to CA in the originally ported box. I don't want them damaged going over and coming back.

I will post after my speakers return. :rofl:

 

[Bucko521]

I bought this from Parts Express. The part number is 290-023. The model number is C16LU20-51F
It is a Pioneer Speaker. 8 ohms. 6 1/2 " which explains having to find a way to mount it. The magnet on the back is huge for this size speaker. That's a good thing. These speakers were not expensive at all. About 40 dollars? Can't remember.
I did not modify or change out the amplifier located in the trunk. I have change everything else. All speakers and the terrible stock CD/radio are gone. If there's anything else I can provide you just shoot me a message.
Cheers..........

V = I x R Voltage = Current x Resistance Ohm's Law

The Z3 amp is about 25 watts per channel
Standard is 2 ohm = R

The 2 ohm load allows more electricity from the amp to flow thru the speaker/sub. With the 8 ohm new sub if the volume is turned up high enough then, amp will try to supply more power to the speakers and something in the amp will give out.

R = V/I
so standard Z3 based on BMW info is as follows.

R = 2
V = 7
I = 7/2
I = 3.5

Now changing up the formula:

R = 8 (new speaker ohm rating)
V = 7 (this does not change)
I = 7/8
I = 0.86

Based on this, your amp will absorb the extra amps...and heat up...you MAY get a premature loss of your amp.

Of course this is up for debate. Other may jump in and provide other info.....and info sharing is always a good thing.

And if you are not using the BMW amp...all best are off on the above info. :dunno::rofl::yikes:

 

[nfunk]

"The 2 ohm load allows more electricity from the amp to flow thru the speaker/sub. With the 8 ohm new sub if the volume is turned up high enough then, amp will try to supply more power to the speakers and something in the amp will give out."

Actually, the 8 ohm speaker pulls less power at same given volume level than the 2 ohm speaker and will allow the amplifier to run cooler. Speakers impedance is the combination of resistance, capacitance and inductance and usually rated at 400Hz. A 4 ohm speaker can have an impedance of 40 to 60 ohms or more at the speaker's resonance frequency.

My two cents.
Nick (an old electrical engineer)

 

[Bucko521]

"The 2 ohm load allows more electricity from the amp to flow thru the speaker/sub. With the 8 ohm new sub if the volume is turned up high enough then, amp will try to supply more power to the speakers and something in the amp will give out."

Actually, the 8 ohm speaker pulls less power at same given volume level than the 2 ohm speaker and will allow the amplifier to run cooler. Speakers impedance is the combination of resistance, capacitance and inductance and usually rated at 400Hz. A 4 ohm speaker can have an impedance of 40 to 60 ohms or more at the speaker's resonance frequency.

My two cents.
Nick (an old electrical engineer)

I love this group!! :thumbup:

I'll trust an "electrical engineer" with that knowledge. I cannot fault your logic at all...8 ohm should pull less.

I know from experience my statement proved also true as the amp heated up more with a higher impedance. I had always suspected it was only one of the three variables changed, and if V = I x R Voltage = Current x Resistance (Ohm's Law) was used...then I'd imagine the current was raised, thus causing heat in the amp.

Perhaps you can explain why that would be as learning why that happens might provide better education for all. :bigpimp:

 

[UncleDavid]

Protecting the Amp

I am going to use a pair of the feed wires into a compact sub woofer with a built in amp behind the seat.

The low profile of these powered woofer amps makes an easy solution. :dunno: