[Billfitz]

I'd help there if I could, but hens teeth are far more common than specs for door drivers. I do know my stock hi-fi units are spec'd pretty much ideally. It's not like the transducer engineers at Harmon don't know what they're doing.

[sparkymarky]

Just realised anyway that the Jehnerts are 6 ohm...so the 7bmw, rated at 160wrms into 2 ohms, would be delivering significantly less power (cnversation about impedance changing with frequency aside) if seeing 6 ohms. Unsure of the calculation to work out its 6 ohm power compared to 2 ohm though....

[sparkymarky]

I think if, after a while i decide to move on from the stock hifi 676 underseats, a good choice, given your input Bill, and that i have a trunk sub for <60hz, could be the ground zero underseats as they have an Fs of 59hz.

They are 2 ohm meaning the 7BMW amp could safely deliver up to its stated 160wrms to each.

https://audio-hi.fi/download/pdf/Gro..._datasheet.pdf

[sparkymarky]

In that factsheet it says sensitivity is 89db,
download the owners manual and it says 86db????

https://www.ground-zero-audio.com/wp...-OM_022020.pdf

[Billfitz]

Originally Posted by sparkymarky

Just realised anyway that the Jehnerts are 6 ohm...so the 7bmw, rated at 160wrms into 2 ohms, would be delivering significantly less power (cnversation about impedance changing with frequency aside) if seeing 6 ohms. Unsure of the calculation to work out its 6 ohm power compared to 2 ohm though....

Ohms Law. There are on line calculators. I saw they were rated 6 ohm on the sales page, but the data sheet says 4 ohms. If they stated Re then we'd know for sure, but it's nowhere to be found.

In that factsheet it says sensitivity is 89db,
download the owners manual and it says 86db????

It's 89dB. Response is virtually identical to OEM. Most are very similar, because from a given enclosure size and desired result there's a fairly small range of specs that will give the best possible result. If the OEM were cheap poorly engineered drivers their specs wouldn't be within that range, meaning there woud be significant room for improvement. But that's not the case, no matter what the advertising for replacement drivers says.

[sparkymarky]

Thanks Bill, great info.

I've just spent an hour doing a first time alignment with the 7bmw amp since quickly installing and downloading the bmw hifi dsp profile to it the other day.

No microphone yet though so not able to level match the speakers beforehand, which may yield a bit further performance too when i get a mic.

But, after time aligning all speakers individually with the tape measure and then fine tweaking a click or two using human voices, wow i must admit i am impressed by the stock speakers sound now. Underseats sound really pretty darn good now (150hz down to 30hz with a 24db butterworth cut) and dont actually think i need any more LFE than they now provide (as long as they last The mids and teeeters (notched their hpf crossover up a little to 135hz upwards) are much improved in both presence, tone, clarity and soundstage up across the dashboard. Time alignment tinkering has managed to put the focal point somewhere around the edge of the rear view mirror (the edge to my side). Bass sounds upfront rather than underseat too, which can be an issue as bass, as we know, becomes directional to the human ear over 80hz or so. So thats good.

I'll spend a couple weeks with it out on the road before i settle, but i may well just live with just this amp this time round. - i'm usually a replace all speakers and amps kinda guy until i hit a sound that is something decent, but this little amp has worked wonders in tuning the stock speakers to the car environment already, well, to my ears anyway

[Diirek]

UPDATE:

I finally had time to install the earthquake underseat woofers yesterday. The install was easier than expected and really was a breeze with the technic pnp mounting rings.

Initial impression is that there in finally some clean, deep lower end to all of my music. the best part is that it is at all volumes, so you don't have to crank the volume to get some good tone.

If you want to push them, they will respond and really make some noise. That being said, if all you're looking for is some added bass, I'd probably have to recommend an aftermarket amp and trunk enclosure/sub. The pnp audiotech Fischer amp with these woofers is a very expensive option if all you were missing was some low end.

I am happy that everything is clean and hidden and works as advertised. I still need to connect to the amp and adjust the sound profile but that is for another day.

[ketchupnsketti]

Not an 3 series but wanted to comment. I have the Match amp in my M2 with bavsound's ghost subs and speakers all around.
It is quite good but my biggest issue is still the bass. The bass boost in the amp was fantastic but I just don't feel like the underseats can hit the low frequencies well enough and I found myself having to compensate by increasing their volume too much. So I would get a lot of bass sound but it still just seemed to be lacking in the very low end.

I finally broke down and removed my rear parcel shelf and cut a hole large enough to the fit the bottom of a sub, bought a small shallow mount 8" and mounted it in the rear deck. I was then able to decrease the volume on the under seats and I really feel like I've hit the sweet spot here. Very nice sound and a nice thud in the center of your chest when the bass drum is struck.

[pierreye]

Cool mod. I’m considering cutting the ski pass on rear middle arm rest in my F10 without folding seat. Then built a sealed 12” pointing in thru the ski hole.

[NR2]

Originally Posted by Billfitz

Don't change speakers until you hear what the stock speakers sound like with a new amp. Contrary to what the advertising says the OEM speakers are high quality. I've yet to see any real engineering data that indicates replacement drivers are actually upgrades, from any company.

Bill, you seem pretty solid on this whenever the issue arises. Do you know anything about what speakers are in the 2016 M235i? I'm in the same boat here and think I'll start with the amp upgrade but keep thinking speakers will be needed. What do you think? Thanks!

[chowser51]

Originally Posted by pierreye

Cool mod. I’m considering cutting the ski pass on rear middle arm rest in my F10 without folding seat. Then built a sealed 12” pointing in thru the ski hole.

Let us know if you ever get this done. I don’t have the ski box since I have the F33. There’s a lot of space for me to install a sub behind the seat since my wind deflector is always installed (I don’t use the car if I have more than one passenger).

[Billfitz]

Originally Posted by NR2

Bill, you seem pretty solid on this whenever the issue arises. Do you know anything about what speakers are in the 2016 M235i? I'm in the same boat here and think I'll start with the amp upgrade but keep thinking speakers will be needed. What do you think? Thanks!

The speakers are the same as with any F series with the same audio system. That makes the worth, or lack of it, of changing the speakers the same as with any F series.

[pierreye]

Originally Posted by chowser51

Let us know if you ever get this done. I don’t have the ski box since I have the F33. There’s a lot of space for me to install a sub behind the seat since my wind deflector is always installed (I don’t use the car if I have more than one passenger).

Sure. My wife said I have too many projects on hand. Still pending my home theater speakers new build and one more 18" subwoofer.

[NR2]

Originally Posted by Billfitz

The speakers are the same as with any F series with the same audio system. That makes the worth, or lack of it, of changing the speakers the same as with any F series.

Thanks, Bill. It seems clear from your previous posts you think it usually ISN'T worth it!

I think I'm going to order a Match UP7BMW to replace the factory amp. I'm going with the plug-n-play because it seems like a decent product and I don't have time to learn a new trade at the moment!

That said, the tuning software looks fairly complicated to use for someone not in the business. Do you think a user with little experience and at least average intelligence can make this thing work or will I need to pay someone to tune this thing for me?

Thanks again!

[Billfitz]

Replacement speakers would make sense if the OEM speakers were cheap junk. But they're not. I could even quote the touted features of one brand of speakers and those features are exactly the same as what's found in the OEM. I'm sure there are plenty of Match Up users who can help with the tuning process.

[wilbur_the_goose]

Originally Posted by Billfitz

Replacement speakers would make sense if the OEM speakers were cheap junk. But they're not. I could even quote the touted features of one brand of speakers and those features are exactly the same as what's found in the OEM. I'm sure there are plenty of Match Up users who can help with the tuning process.

Agree - The shop that I bought the Match told me not to waste $$$ on speaker replacement. Said that the speakers were fine, but the stock amp was horrible.

[Af32]

Originally Posted by Diirek

UPDATE:

I finally had time to install the earthquake underseat woofers yesterday. The install was easier than expected and really was a breeze with the technic pnp mounting rings.

Initial impression is that there in finally some clean, deep lower end to all of my music. the best part is that it is at all volumes, so you don't have to crank the volume to get some good tone.

If you want to push them, they will respond and really make some noise. That being said, if all you're looking for is some added bass, I'd probably have to recommend an aftermarket amp and trunk enclosure/sub. The pnp audiotech Fischer amp with these woofers is a very expensive option if all you were missing was some low end.

I am happy that everything is clean and hidden and works as advertised. I still need to connect to the amp and adjust the sound profile but that is for another day.

This may be a stupid question but I have the match 7 amp installed and am going to swap my stock subs for the earthquake 2ohm subs
The max rating for them is 150 watts but the amps max is 160 watts. How do I limit the amps output

[Billfitz]

You don't. In use you'll seldom exceed 20 to 30 watts continuous. The reason you need more power than that is to allow for transient peaks, which would cause distortion if you didn't have amp headroom. If you were to run at even 100 watts continuous those transients would create distortion so bad that it would be unlistenable. To insure adequate headroom it's not uncommon for high end home hi-fi and home theater systems to have twice the power or more on tap than the speakers are rated for.

[Af32]

Originally Posted by Billfitz

You don't. In use you'll seldom exceed 20 to 30 watts continuous. The reason you need more power than that is to allow for transient peaks, which would cause distortion if you didn't have amp headroom. If you were to run at even 100 watts continuous those transients would create distortion so bad that it would be unlistenable. To insure adequate headroom it's not uncommon for high end home hi-fi and home theater systems to have twice the power or more on tap than the speakers are rated for.

Understood. Thank you so much. I appreciate it.

[Af32]

Originally Posted by Billfitz

You don't. In use you'll seldom exceed 20 to 30 watts continuous. The reason you need more power than that is to allow for transient peaks, which would cause distortion if you didn't have amp headroom. If you were to run at even 100 watts continuous those transients would create distortion so bad that it would be unlistenable. To insure adequate headroom it's not uncommon for high end home hi-fi and home theater systems to have twice the power or more on tap than the speakers are rated for.

I just bought a harness on eBay so that I didn't have to cut the factory wires when I sinstall the subs.

Was wondering if I should remove the Jumper looped wires or do they not do anything.

[ALara]

Any comments on my plan to improve the HiFi on my 2017 F31.
OEM speakers
Match amp
10 inch side sub box
JL or Kicker 10 inch shallow dual voice coil 4 ohm
kicker kxa 800.1

[Billfitz]

Looks good, but I'd also add rear door tweeters.