B&O speaker sizes and impedances
09-24-2018, 01:39 PM
#11
The added strain to the amp could easily overheat it and cause it to fry.
If the amp doesn't have 2 ohm stability, then any added sub volume will be negated by a blown amp.
I'm more a fan of single voice coil subs, as sub frequencies are not directional, especially in a car environment.
DVC simply gives the user more flexibility in wiring for various amps.
In a system with known amp capability I don't know why B&O would have selected a DVC sub.
It seems the OEM sub is an 8ohm DVC so it's likely wired for a 4ohm load.
However, you could just as easily get a SVC 4ohm sub, pay less money and get the same output.
Last edited by TT-S4; 09-24-2018 at 01:42 PM.
09-24-2018, 01:40 PM
#12
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.
All the data is in the spreadsheet linked below.
B&O Audi B9 Speaker specs spreadsheet
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.
All the data is in the spreadsheet linked below.
B&O Audi B9 Speaker specs spreadsheet
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.
Thanks.
09-30-2018, 10:03 AM
#13
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Sorry I've been lagging behind on completing this project. My wife and I have a baby due around thanksgiving and I've been super busy getting her bedroom ready. I can answer some of the questions though:
JL slim sub has the same impedance as the factory sub so it is a safe drop in replacement from an electrical perspective. I did some math and I think it will roll off sharply below 40Hz, which is just like the factory sub so I doubt it will play any deeper, but it certainly will be tighter and cleaner. I measured the bass decay of the factory sub and it's pretty atrocious. Need to check mechanicals for fitment.
I think there is some value in adding a better midrange in the front doors. Something a little less bright with better midbass performance. Crossover points being what they are limit my hopes here. Need to check the mounting depth on the door midrange.
There is active processing going on and short of firmware hacking, I think the only way to disable it would be to gut the entire system and build a new one. This would be a major undertaking but not impossible as the B&O electronics are a separate module from the rest of the stereo. You'd have to pin out the cable harness and identify all the important signals.
Regarding the tone controls, I discovered that the bass adjustment overlaps the subwoofer adjustment. Bass boosts 20-500 hz but subwoofer boosts 20-70 hz. For this reason I suggest turning the subwoofer down until you adjust the bass where you like it, and then adjusting the subwoofer up to your preferred listening position. To get decent mid bass I set the bass to the 3:00 position and then after that settled out around +2 on the sub. The tweeter I set to -1. I'd suggest turning the 3D effect off, or if you really like it, set it to low. The 3D effect only turns on the dash mids and upper A pillar tweeters and makes the system even brighter. As there is no midrange tone control, it can only be set with the volume ****. When making tone control adjustments set the volume to your comfortable midrange level first, then adjust other tone controls second. Lastly the road noise of the car is mostly in the midbass range so once you find your bass setting, don't be surprised if you bump it up 1 or 2 more for actual driving. These settings are just guidelines and will vary according to your personal taste and the type of music you like.
Speaking of driving, I'm not super comfortable with the way I mount the microphone and it's quite fragile so I'm not going to take any measurements while driving. The software requires a lot of attention and would have to be operated by another person sitting in the back seat and holding the microphone in their hand.
JL slim sub has the same impedance as the factory sub so it is a safe drop in replacement from an electrical perspective. I did some math and I think it will roll off sharply below 40Hz, which is just like the factory sub so I doubt it will play any deeper, but it certainly will be tighter and cleaner. I measured the bass decay of the factory sub and it's pretty atrocious. Need to check mechanicals for fitment.
I think there is some value in adding a better midrange in the front doors. Something a little less bright with better midbass performance. Crossover points being what they are limit my hopes here. Need to check the mounting depth on the door midrange.
There is active processing going on and short of firmware hacking, I think the only way to disable it would be to gut the entire system and build a new one. This would be a major undertaking but not impossible as the B&O electronics are a separate module from the rest of the stereo. You'd have to pin out the cable harness and identify all the important signals.
Regarding the tone controls, I discovered that the bass adjustment overlaps the subwoofer adjustment. Bass boosts 20-500 hz but subwoofer boosts 20-70 hz. For this reason I suggest turning the subwoofer down until you adjust the bass where you like it, and then adjusting the subwoofer up to your preferred listening position. To get decent mid bass I set the bass to the 3:00 position and then after that settled out around +2 on the sub. The tweeter I set to -1. I'd suggest turning the 3D effect off, or if you really like it, set it to low. The 3D effect only turns on the dash mids and upper A pillar tweeters and makes the system even brighter. As there is no midrange tone control, it can only be set with the volume ****. When making tone control adjustments set the volume to your comfortable midrange level first, then adjust other tone controls second. Lastly the road noise of the car is mostly in the midbass range so once you find your bass setting, don't be surprised if you bump it up 1 or 2 more for actual driving. These settings are just guidelines and will vary according to your personal taste and the type of music you like.
Speaking of driving, I'm not super comfortable with the way I mount the microphone and it's quite fragile so I'm not going to take any measurements while driving. The software requires a lot of attention and would have to be operated by another person sitting in the back seat and holding the microphone in their hand.
Last edited by Bobby Kinstle; 09-30-2018 at 10:05 AM.
10-01-2018, 07:28 AM
#14
Sorry I've been lagging behind on completing this project. My wife and I have a baby due around thanksgiving and I've been super busy getting her bedroom ready. I can answer some of the questions though:
JL slim sub has the same impedance as the factory sub so it is a safe drop in replacement from an electrical perspective. I did some math and I think it will roll off sharply below 40Hz, which is just like the factory sub so I doubt it will play any deeper, but it certainly will be tighter and cleaner. I measured the bass decay of the factory sub and it's pretty atrocious. Need to check mechanicals for fitment.
I think there is some value in adding a better midrange in the front doors. Something a little less bright with better midbass performance. Crossover points being what they are limit my hopes here. Need to check the mounting depth on the door midrange.
There is active processing going on and short of firmware hacking, I think the only way to disable it would be to gut the entire system and build a new one. This would be a major undertaking but not impossible as the B&O electronics are a separate module from the rest of the stereo. You'd have to pin out the cable harness and identify all the important signals.
Regarding the tone controls, I discovered that the bass adjustment overlaps the subwoofer adjustment. Bass boosts 20-500 hz but subwoofer boosts 20-70 hz. For this reason I suggest turning the subwoofer down until you adjust the bass where you like it, and then adjusting the subwoofer up to your preferred listening position. To get decent mid bass I set the bass to the 3:00 position and then after that settled out around +2 on the sub. The tweeter I set to -1. I'd suggest turning the 3D effect off, or if you really like it, set it to low. The 3D effect only turns on the dash mids and upper A pillar tweeters and makes the system even brighter. As there is no midrange tone control, it can only be set with the volume ****. When making tone control adjustments set the volume to your comfortable midrange level first, then adjust other tone controls second. Lastly the road noise of the car is mostly in the midbass range so once you find your bass setting, don't be surprised if you bump it up 1 or 2 more for actual driving. These settings are just guidelines and will vary according to your personal taste and the type of music you like.
Speaking of driving, I'm not super comfortable with the way I mount the microphone and it's quite fragile so I'm not going to take any measurements while driving. The software requires a lot of attention and would have to be operated by another person sitting in the back seat and holding the microphone in their hand.
JL slim sub has the same impedance as the factory sub so it is a safe drop in replacement from an electrical perspective. I did some math and I think it will roll off sharply below 40Hz, which is just like the factory sub so I doubt it will play any deeper, but it certainly will be tighter and cleaner. I measured the bass decay of the factory sub and it's pretty atrocious. Need to check mechanicals for fitment.
I think there is some value in adding a better midrange in the front doors. Something a little less bright with better midbass performance. Crossover points being what they are limit my hopes here. Need to check the mounting depth on the door midrange.
There is active processing going on and short of firmware hacking, I think the only way to disable it would be to gut the entire system and build a new one. This would be a major undertaking but not impossible as the B&O electronics are a separate module from the rest of the stereo. You'd have to pin out the cable harness and identify all the important signals.
Regarding the tone controls, I discovered that the bass adjustment overlaps the subwoofer adjustment. Bass boosts 20-500 hz but subwoofer boosts 20-70 hz. For this reason I suggest turning the subwoofer down until you adjust the bass where you like it, and then adjusting the subwoofer up to your preferred listening position. To get decent mid bass I set the bass to the 3:00 position and then after that settled out around +2 on the sub. The tweeter I set to -1. I'd suggest turning the 3D effect off, or if you really like it, set it to low. The 3D effect only turns on the dash mids and upper A pillar tweeters and makes the system even brighter. As there is no midrange tone control, it can only be set with the volume ****. When making tone control adjustments set the volume to your comfortable midrange level first, then adjust other tone controls second. Lastly the road noise of the car is mostly in the midbass range so once you find your bass setting, don't be surprised if you bump it up 1 or 2 more for actual driving. These settings are just guidelines and will vary according to your personal taste and the type of music you like.
Speaking of driving, I'm not super comfortable with the way I mount the microphone and it's quite fragile so I'm not going to take any measurements while driving. The software requires a lot of attention and would have to be operated by another person sitting in the back seat and holding the microphone in their hand.
Best wishes for your family.
I know this a very busy time for you and your wife, so thanks for getting the information you have.
I could tell that the bass control and the sub control were crossing each other. As I was playing around and adjusting and testing things by ear, I could note that those two controls do indeed affect each other, unfortunately.
Thanks for confirming what I hear.
Why they choose to do that is up to them to answer, because I wouldn't have done what they did.
Their method is ridiculously and overly complicated to begin with.
After more listening and experimenting with settings ast week, I settled on some settings for now.
I have "surround" and 3D turned OFF. Doing that cleans up the mid-bass a bit.
Also, I set the focus/speakers to "Front" and sometimes "All", depending on what I'm listening to.
Treble is at maximum.
Bass set to 2-3 notches above noon.
Sub set to noon or 1 notice above.
Fade set to about 2 clicks towards dash. This setting raising the center stage location. It's part of the system, and it's interesting and works.
Interestingly, I'm hearing decent mid-bass at moderate volume levels, which is in contrast to others who say there isn't enough mid-bass and/or it's lacking in quality.
Cranking up the volume at a certain point leads to noticeable compression, and the mid-bass and mids take on a dull wooden quality, as the dynamics get squashed by the compression.
All modern OEM systems do that, but I expected better still. The HK system in my last 3 BMW's also had compression at higher volumes, but it still managed to retain better dynamics with clarity, along with a much tighter and deeper sub bass.
I'm going to try and go to my local dealer some time this week and listen to a few of the same B&O systems in A4/A5s on the lot. The A3 has a different setup and didn't sound as good compared to the A4/A5 setup.
There is still an issue with my sub as often it won't come on when the system fires up, and will only come on after an MMI reset.
However, since I turned 3D and surround OFF I have noticed that the sub comes on with the system much more often.
I'm not that hopeful that an automotive tech will figure out the issue, but there is always hope that the dealer service department has a person who does know about audio systems.
Still, I'd be happy if they just replaced the sub, amp, and HU or processor, until it gets working properly.
10-10-2018, 07:07 AM
#15
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Hi, I'm new to Audi with the recent purchase of a B9 S4 and this thread caught my eye. Do the speakers in the pillars actually work? There appears to be 2 in each pillar, but I'm yet to hear sounds coming out of any listening to radio, CD or Bluetooth audio. I think 2 might be speakers and 2 might be microphones for BT and voice commands? (My apologies if this is already covered in another thread)
Thanks
Thanks
01-19-2024, 07:22 AM
#16
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01-20-2024, 09:07 AM
#17
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