When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I've been doing some digging on the B&O speakers lately as I've been thinking of replacing some of them to make the mid bass and sub bass better.
Front doors:
1" dome tweeter 4Ohm, 20W
3" midrange 4 Ohm, 20W
4x6" woofer 8 Ohm, 100W (WTF, yes you read that right)
Rear doors
1" dome tweeter 4Ohm, 20W
Could be 5.25" or 6.5" woofer, will require lots of cutting. 2 Ohm, 40W
Dash/A pillars:
1" dome tweeter 4Ohm, 20W
3" midrange 4 Ohm, 20W (the 3D effect mids are slightly smaller than the center/door mids)
Rear Deck:
3" midrange 4 Ohm, 20W
10" Subwoofer, Dual voice coil, 8ohm per coil. Power rating unknown. Probably not more than 250W.
Now I need to send some test tones and figure out the crossover points. I really want that bass guitar/cello to come through. If it's on the mid, then I'm golden, but if it's on the woofer I'm probably porked.
is the sub wired for a 4 Ohm load? wonder who's going to be the first to replace that shallow mount sub with another.
I haven't figured that part out yet as I'd need to unplug it and see. I will replace this sub. Mark my words. I replaced the sub in my B8.5 S4 with a big honking Pioneer Champion series DVC woofer.
This is great information perfectly timed
I will be doing similar in the coming weeks using a kicker comp c sub and twister F4 260 amp (had it at home so no point spending on another amp) will feed it around 250rms which should be plenty. I think the factory sub is wired as two channel so separate feeds to each coil given there are 4 wires going to it.
The front door midbass drivers will probably need upgrading at some point.
hopefully you will get your hands dirty before I do
The real question of what the amp can handle, ie what you can get away with, has a lot to do with your listening levels. If you are running the amp at or above half it's rated output, then going to a 4 ohm speaker will cause problems, and probably damage the amp. However if you never run the sub above that level, then there's a really good chance you'll get away with it. Sometimes circuits try to make measurements about behavior by watching the current flow, and in those cases changing the impedance can still have undesired effects.
I've been sending test tones to try to list out the crossover points and I will update this thread with that data soon.
I've been able to approximate some crossover points by sending test tones to the speakers with the balance and fader set only to the corner I was testing. This works pretty well to isolate one door at a time. It does not work well in the front and rear surround sound speakers, but since they use the same looking drivers as the doors I'm just going to assume they have the same ranges. One exception is the two 3d effect midranges are smaller than the center/door/rear deck midranges so for now I've labelled them 3" and 3.5" respectively. Also there is not a hard cutoff between the drivers so I did my best to put the frequency before I noticed a big volume change and I used my ears for that so the exact roll off frequencies are probably not exactly correct (except in the case of the subwoofer which was very clear). Nor did I spend a lot of time trying to narrow down the mid-tweeter points to better than 500hz increments. Some of this data is very disturbing. For example the front door woofer is the only speaker in the car for 70-160Hz as the rear door speakers appear to have a high pass filter at 160Hz. It's no wonder the mid bass sucks and there's probably very little we can do to fix it.
The next step is to borrow the good quality test microphone from work and do some frequency sweeps to get volume level vs frequency. My goal is to find tone control settings that get the flattest possible frequency response with the factory speakers. This will probably go off the rails with the 3D effect turned on so I'm just going to turn it off during the test.
I've been able to approximate some crossover points by sending test tones to the speakers with the balance and fader set only to the corner I was testing. This works pretty well to isolate one door at a time. It does not work well in the front and rear surround sound speakers, but since they use the same looking drivers as the doors I'm just going to assume they have the same ranges. One exception is the two 3d effect midranges are smaller than the center/door/rear deck midranges so for now I've labelled them 3" and 3.5" respectively. Also there is not a hard cutoff between the drivers so I did my best to put the frequency before I noticed a big volume change and I used my ears for that so the exact roll off frequencies are probably not exactly correct (except in the case of the subwoofer which was very clear). Nor did I spend a lot of time trying to narrow down the mid-tweeter points to better than 500hz increments. Some of this data is very disturbing. For example the front door woofer is the only speaker in the car for 70-160Hz as the rear door speakers appear to have a high pass filter at 160Hz. It's no wonder the mid bass sucks and there's probably very little we can do to fix it.
The next step is to borrow the good quality test microphone from work and do some frequency sweeps to get volume level vs frequency. My goal is to find tone control settings that get the flattest possible frequency response with the factory speakers. This will probably go off the rails with the 3D effect turned on so I'm just going to turn it off during the test.
Commendable effort.
Thanks for doing all that.
I will be very interested to read what you discover.
I read some disturbing, at least to me, information about the B&O system in our cars.
From B&O's website it appears that our system is "active", and that the audio processor uses mics in the cabin to hear the overall audio alone with any ambient sounds and then automatically adjusts frequencies, including "loudness", in order to attain some unknown reference graph.
If this is true, then it bodes badly for getting a clean flat signal from the HU.
If you discover a way to shut of the auto processor, please let us know.
I want to verify where the system microphones are, and then I want to cover them up with cotton and seal them to hear what the system may or may not do.
Also, I wonder if there is a way to disconnect those mics, if the auto system can't be turned off in some way.
If our system does not have the active audio adjustments, then that would be great to know as well.
However, in my so far limited time with my new S4 I am hearing the overall audio changing with speed.
The tonal quality at idle is not the same at higher speeds.
That said, there is something wrong with my B&O system.
I've had to reset the MMI mulitple times to get the sub woofer to come back on.
At various times once the car has been sitting all day or overnight, the sub won't come on when I start the car.
Then, I reset the MMI and the sub comes back to life.
I've had to do the reset nearly 10 times over the past week.
Over the past 3 days it's been working.
So, it's possible that the processor could be faulty in my system, and I hope it is, because right now I'm not a fan of the B&O system.
My hearing range is not what it used to be, and as many of us get older our high frequency hearing capability drops off.
I don't hear frequencies above 17Khz at equal levels to frequencies below that.
And, by around 19Khz I don't hear that at all.
I have to set my treble to maximum just to get some crispness on the system.
However, most treble is set around the 10Khz range and my hearing is still good there.
So that points to another potential issue with my processor as I don't recall having to boost the treble that high in other A4/S4s I've test driven.
08-07-2018, 10:54 PM
B&O speaker sizes and impedances
