Factory B&O Audio Signal and Max Volume

[LAX-DAD]

Wanted to share what I found with the factory B&O sound system before tearing it out. I'm not a professional just enjoy playing in the garage with toys and with my son on our vehicles. There have been many posts about the audio system in our Bronco's from speaker swaps to full systems but nothing about the audio signal from the B&O dsp feeding the speakers.

I set up my laptop, DM-RTA along with my SMD DD1+ to see what I could measure from the audio signal. For those not familiar with these items, the Audiocontrol DM-RTA a great tool for tuning, measuring and troubleshooting while the SMD DD1+ by D'Amore is a clipping indicator. While the DM-RTA has an oscilloscope for measuring maximum volume or system clipping I found it easier and quicker in this setup to use the DD1+. Keep in mind I measured the electrical signal feeding the speaker, I did not mic and measure the output of the speaker. For each speaker location I played 'pink noise' and measured the signal with wire probes to the speaker wires.

Subwoofer signal

Rear pod speakers

Dash Speakers

Kick Panel

Here are all the signals averaged

For measuring maximum volume, on the subwoofer I played a 40hz test tone. The sub signal volume was clean up to 23 (5.8volts) at 24 on the signal clipped. For the kick panel, dash and rear speakers we played a 1khz test tone. For all three locations the audio signal did not clip all the way to 30 (9volts) on the volume/display. The B&O wiring schematic does show a 'clip detect' circuit not sure if this is why I couldn't get the signal to distort, maybe someone more knowledgeable can elaborate.

If there is something I missed please let me know.

Sponsored

 

[Alfa]

Thanks for posting this. Super interesting to see how they are shaping the signal at the different speaker locations. Might be good data in selecting replacement speakers

 

[BlueBuddha]

Any further development from this. I’ve been digging through posts to determine max volume pre clipping to set dsp at. Great information so far…hoping the thread doesn’t die off

 

[LAX-DAD]

Any further development from this. I’ve been digging through posts to determine max volume pre clipping to set dsp at. Great information so far…hoping the thread doesn’t die off

The clipping test I performed was a matter of curiosity based on the system design. Head unit powering center dash and rear pods while back panel amp front dash corners, kick panels and sub. As mentioned in my original post sub signal was the only channel to clip.

If you have the B&O I am sure you are aware you need to convert the ford A2B interface. I am incorporating the Mobridge to do just that, A2B to toslink in my case. The signal from the Mobridge is also to be 'flat' and will test for that too however the output signal and clipping are an unknown.

Bluebuddha, any change in the audio system will need to be tested and I wouldn't think be the same for all. I've had fun welding up brackets for my amps and attached some pictures for fun to share before the panel goes on. The Mobridge will be feeding an Audison Forza C8.14 dsp amplifier sending sub signal to Audiocontrol LC 1.800. The little Audision amp is an 8 channel with 65 watts per channl however any two channels are bridgeable. I intend to bridge the kick panel 6-1/2" speakers for 200 watts per channel. Will have to check clipping on the bridged out of curiosity too. All that to say if you are doing anything different your results may be different, but I will share.

I like to play so let me help if I can.

 

[mObridge]

Any further development from this. I’ve been digging through posts to determine max volume pre clipping to set dsp at. Great information so far…hoping the thread doesn’t die off

I would highly recommend with any install on a B&O system to put an A2B interface in. This will make the install far easier and will yield better results too.

When it comes to the clip point coming out of our unit this is fully adjustable. We can make it clip at volume 1 if you want. That being said, out of the box we pass the signal straight through. So if youre playing 0db FS signal it will clip at 30 on the dial. If you would like it to clip earlier you can add up to 9db of boost with out PC tool. This will mean it will clip somewhere in the low-mid 20s. You can also take 32db off the signal which will mean it will never clip.

Once you have installed an A2B interface I would completely forget all your previous learned volume positions with the factory amp.

 

[LAX-DAD]

Thank you was unaware it was adjustable the audio out voltage was adjustable. Regarding the audio signal am I correct in assuming it is flat and one less step in the dsp tuning process?

 

[FreddieLee]

No microphone?

The electrical signal compared to the acoustical signal are worlds apart in Bronco's. I use a newer version of AudioControl's SA-4100i for RTA tuning.

Since you're proficient using the DM-RTA, I'm surprised you're not using AudioControl D-series amplifiers.

I'm also surprised you're not running an active 3-way system with the Forza. Phenomenal amplifier.

Multiple grounding points instead of a distribution block?

What subwoofer is the LC powering?

 

[LAX-DAD]

You are more than correct; the audio signal varies greatly from the acoustical. I contemplated hooking up the microphone to do just that, but we've all seen those numbers from others. My objective was to share the electrical in hopes to help those curious with the frequencies fed to each speaker. No to mention had already made changes and pulled the sub before I thought about sharing.

I did purchase the AudioControl D-6.1200 dsp amplifier for that vary purpose. Coupled with the smaller LC 1.800 had its challenges fitting it all (not saying it wouldn't) into the OE subwoofer location like i was able with the Audison. The Forza is a fraction of the size and was curious to try their new dsp system as compared to the AudioControl. My teenage son is happy to have the D-6.1200 coupled nicely with the LC-1.1500 in his truck.

Three-way speaker system run active does have its advantages however other than the subwoofer I'm intending to use all the stock location is my initial objective, even a tweeter mid in the dash as many have done. This is a toy vehicle and I am not building for sound quality, but rather enjoying the journey. Already changed dash speakers twice and have a third in mind as part of my playing around. Removed Audiofrog GS42 for smaller and new AudioControl 3.5" coaxial as the grill opening is 3.5" and want to keep the stock look. Use a wideband Morel ccwr254 for the center channel and I really like its detail and curious how it would sound in the corners as a comparison. May give it a try some day too.

Unlike a JL or Kicker you read about here so often I went back to my youth with a slim Rockford Fosgate sub finishing up on tailgate mounted box. I built the box enclosed for a Fosgate Power T1S2-12 subwoofer. Not a sub you see often and was curious how it will perform so giving it a try. Pulled the box with three JL 10TW3's in my son's truck and wired it up, impressed so far. Just have to finish up cosmetics and vinyl upholstery work to get it installed in the bronco.

 

[FreddieLee]

How do you like Audison's DSP software compared to AudioControl? After downloading and running simulations on JL Audio, Audison, AudioTec (Helix), and a few others, the most difficult was JL Audio, and the easiest was AudioControl, which is why I went with their amplifiers. Audison was doable, and AudioTec was doable too, but that meant purchasing a Windows laptop.

 

[LAX-DAD]

My experience with dsp systems is limited to only the AudioControl and Audison. The AudioControl is simple strait forward and now includes new EQ features that many have complained was lacking. My criticism would be more personal in line with bland DOS like graphics for those of us old enough to remember life before windows. Simple is not bad just different. With Mac can also tune wirelessly with AudioControl Bluetooth doggie.
Audison dsp has more to offer, graphically and electronically. if you need to dial in audio signal from the inputs it has more to offer and few more tuning bells and whistles. Does that make it better? Some say yes, but each system and user have their own needs and objectives. So much comes down to personal taste and what you think you need. The new Forza line to me stood out with their size as well as the flexibility. I like the idea that I could bridge any two channel of the amp. I went with the compact C so the power is almost half of what the AudioControl however they also make a larger M amp with more power. If needed. Again personal preference and application.
In reference to your earlier question and running a ground block.
With the bronco there were a couple sub mounting studs that I was able to clean up and used, one for each amp individually. This made two short clean a runs. The photos attached show the ground location and in second photo the factory ground above the amps. I choose to keep it short and clean.

 

[mObridge]

Thank you was unaware it was adjustable the audio out voltage was adjustable. Regarding the audio signal am I correct in assuming it is flat and one less step in the dsp tuning process?

Signal will be dead flat from 20hz to 20khz.

Sponsored