Replacing woofer/footwell

[Tfalsetta]

I need to replace the woofer in the foot well on the right side of my 1998 Z3M. It’s blown. If I could, I would replace the speaker with the exact Harman kardon model if possible….however from what I’ve been reading, they’re not easy to find. Are there any recommendations on a speaker that fits ideally exactly

Thanks in advance

[Pima Roadster]

For whatever reason, BMW & other manufacturers use stereo equipment that is odd as to amps, ohms & maybe size, or combinations thereof. Aftermarket is limited if anything & of course the OEM stuff is discontinued. Once you start on the slippery slope of replacement the end result is often everything has to be replaced & that is costly. Usually the outer cone of the speaker is what fails. I have used kits from this company to repair the speakers in the Roadster & in the house stereo equipment. https://www.simplyspeakers.com/ Usually it is the outer portion of the cone which fails & this is easily replaced. This repair will help the audio to return to what the original setup was but not improve it. From my reading, the weakest link in the chain is the amplifier but other folks will need to raise their voices about this. Way beyond my pay grade & good luck!

[z3forlife]

I’m using a set of alpine 5 1/4” and they match the mounting points perfectly. MBQUART also match.

[Tfalsetta]

Thanks...Are you able to provide a URL?......When you say fit perfectly..Do you need to do any modifications at all...or does it simply replace existing woofer?

[robb1887]

I have some HK woofers on the shelf. Used of course.

[Tfalsetta]

ok assuming they work.....are you looking to sell them....I really want to keep this simple and ideally replace like for like

[delvec]

There are plenty of 5-1/4" aftermarket speakers that will fit. However, the majority of them are 4 Ohm. I believe the footwell HK speakers are 2 Ohm. There are not many 2 Ohm 5-1/4" aftermarket speakers to choose from..If you decide to go aftermarket you will need to confirm the depth that it is comparable to the OEM speaker depth.

[Tfalsetta]

thanks.... What's the downside of putting a 4 ohm vrs a 2 ohm..... I mean technically it's double the resistance... But I'm not sure what that translates into..... Yes I'm trying to find the depth.... I read somewhere that it's 2 7/8 ( basically 3 inches)

[robb1887]

Twice the resistance equals half the volume

[Tfalsetta]

UGH....That's what we call real imbalance.... Okay thanks for the tip.... Ideally I want to try to find a 2 ohm..

[spfd72]

Twice the resistance equals half the volume

hence the "slippery slope begins..." depends on how far you want to go down the rabbit hole

[z3forlife]

Mine went in without modification. Depth shouldn’t be a problem there’s a good bit of room. The only mod required might be trimming the back side of the kick panel depending on cone travel. 4 ohm will be quieter but I wouldn't say by half. Amp replacement isn’t too tough if you want to keep the stock head. I’d pull rca cables if replacing the head though it makes amp swap even easier. Then all you need are the speaker wires and remote amp on wire from the harness. You can find the schematic at we do phones dot com.

[Tfalsetta]

sorry not sure if I ever asked.... Were you looking to get rid of/sell the HK Woofers you have?
tfalse99@gmail.com

[s8ilver]

4 ohm will be quieter but I wouldn't say by half.

The math would support this. While doubling the resistance halves the wattage the speaker will see, the dB, or volume, will decrease by a smaller percentage. The difference is more apparent in the higher wattage levels. This is why a lot of audiophiles say you can never have too much power. out of an amp Sure, you can blow speakers if you max the gain and crank it, but you can also drive just about any speaker at its max potential without overdoing it. A 400W/ch amp makes 100W speakers sound way better than say a 75W/ch amp ever could.

Also, you'll perceive 100dB as 4x as "loud" as 80dB. However, the "volume" only increased by 25%.

speaker-impedance-4-ohm-vs-8-ohm-power-volume-graph.pngspeaker-impedance-power-watts-vs-ohms-graph.png