Rikki-Tikki-Tavi

Excellent write-up; well-played.

Loe

I actually ended up with a Pioneer 10" shallow sub box (https://www.pioneerelectronics.com/P...er/TS-WX1010LA), it was $259.95 on Amazon, sounds great, but it doesn't play the ultra low notes (sub 38Hz) very well no matter how much I tried adjusting the settings.

I ordered a Focal Bomba BP20 in hopes that it does in fact hit the advertised 20Hz area that the Pioneer promised on spec, but failed to deliver.

You can hardly tell the Pioneer is in the trunk though...less than 6" in depth

Loe

Update, so the Focal didn't work out either. I'm starting to think its limitations on the MMI system and how it wants to use bluetooth or USB signals to artificially roll off certain notes no matter how I tune the system when using Android Auto. I know in prior Audi's/VW's, the sound system usually plays full range notes on Apple Carplay so I'll give that a shot.

hwalkerTTS

Can I ask if you pulled your line-out signal from your front or rear speakers.? The MMI does not feed the rear speakers anything below 50hz, so make sure you connect your line out to the fronts.

Loe

I tapped into the front speakers based on the lines pictured on the 1st page of the thread.

But since these are dual-voice coils, I'm now wondering if we need to tap into both lines on each speaker to get a true performance?

When I play a test tone via youtube video, my current set-up with the Pioneer 10" will start rumbling aroud 27Hz, and really build up at 32Hz, but it doesn't seem to happen at all using other music sources via bluetooth or Android Auto. I may try to burn a CD, have not done that in years LOL, just to see if something is holding back on the frequency. I even tried playing music via Youtube video that I know have low frequency notes but nothing, it will only play on those test tones.

But I did update one thing between, I changed the speaker-level input mV on the Wavtech LinkDQ from 20mV to 40mV, which helped it out some in the low notes by balancing out the 40+Hz more, but it still doesn't appear to have a robust response below that mark.

The notes are there on regular tracks, dont get me wrong, but the roll off still is still something I'm trying to resolve.

Just find it strange that it's stronger on test notes vs regular music tracks.

hwalkerTTS

If your MMI has high level output, you could tap in there. I expect the B&O system uses fibre optic from the head unit to the under seat amp? If it uses wired outputs, you can leverage the white and grey wires that run into the under seat amp.

Loe

I want to say its a digital input, so it wouldn't have the usual channels to tap into as an input into the B&O amp.

It's not that it won't play those notes, it just won't play them from regular music but will on a test tone. I'm going to try a WavTech BassRestore again and switch it back to 40mV on the unit to see if it improves it over the LinkDQ unit.

Loe

Update. I started playingn aroudn with the location of my sub.

Previously I had my sub rearward facing towards the back.

I moved it around the trunk/hatch and found that with my particular sub, it needed to be at a 180* phase & forward facing against the back seat. Now it will play music down to 32-35Hz and at times, register below that down to 27Hz (albeit with a roll out). I still have to play around with my LinkDQ gain + the subwooder's bass boost settings though. The downside to this is bass above 45Hz seems to be timed too "in-phase" with the front door speakers (which do not product much), so the system is now sub-bass heavy relative to bass/mid-bass. If I turn up the gain too much, it will discover those 45Hz+ but a little too loud bass for my tastes.

More to play around, but happy to find sub bass. I may end up trying a 12" sub now that I understand placement and phasing is really important and I was under the impress that a rearward facing (against the seat back and firing towards the hatch) was the best, but in my case it isn't.

Loe

I kid....I was adjusting the bass boost the entire time and not the crossover frequency. Now it gives me full bass.

Now I want to go back and try that WavTech BassRestore again that has a +18dB vs the +12dB of the LinkDQ

Look at my frequency analyzer, this sub rocks for $250-ish, $90 active LOC, and a $70 8 Guage wiring kit. Here it's hitting a bass note that registered 32Hz:

Loe

https://www.kicker.com/keyloc-smart-line-out-converter

This active LOC has a built-in DSP to level out the EQ curve +/- 12dB across 20 Hz-20kHz

This should be pretty decent (I ordered one and should be here tomorrow). I've been so focused on adding dB to certain area's, but not smoothing out the area's that the OE signal likes to peak at for the front "bass" woofers, mainly frequencies centered around 50Hz by also reducing the dB in this area to flatten out the curve. Basically it has an auto EQ, I'll have to send feedback soon, but reviews on Crutchfield and Amazon are favorable.

Edit, installed. Wow, this cleaned up the signal completely and flattened out the entire low frequency curve. learning as I go, but now it sounds perfect, nice and flat bass response down to 27hz, just beautiful without over powering, blends right in.

Edit wow! I hooked it to feed I to the LinkDQ with its bass boost tech, wow the bass between 27-40Hz is incredible!