Underwhelming BeoLab 19 subwoofer + BL18s

[Stefano A Barbier]

I recently added a BeoLab 19 subwoofer to the pair of BeoLab 18s. I connected it via the Transmitter 1 (through WISA). I find that the subwoofer, particularly at lower volumes is very underwhelming (almost non existent). Reading the marketing material on “filling the room”, “earth shaking bass” – I feel like I’m missing something. I believe I’ve connected it right, see settings below, but any help or feedback would be appreciated. I’ve read all the forums online that I can find to diagnose, and it seems that this is a regular issue among other people.

Settings: Transmitter 1: 18s on PL1, 19 on L PL2, 2.1 On. Connected to an Airport Express (Airplay 2) with aux to RCA playing Spotify Lossless.

On 19s: Gain 0, low pass filter OFF, Freestanding, L+R, wireless.

When I move the bass Gain to max, it sounds almost enough at low volumes, but maybe too much at higher volumes. I know the 2.1 is setting correctly because the 18s are no longer putting out lower frequencies. With the 18s on their own with no subwoofer the bass at lower volumes is actually quite good, better than the beolab 19, but lacks at higher volumes. I found another forum post here where someone was mentioning something similar and how they went wired with powerlink to solve this problem but with tradeoffs on bass at higher volumes. Also if I leave the transmitter 1 on 2.1 setting, which correctly cuts out the low range from the 18s, but turn the low pass filter on and to to 120hz and gain up on the 19 I’m getting closer to the bass that I am expecting, yet I’m not sure why this works or what tradeoffs might be since its double filtering.

Any advice on how I can get the 18s + 19 to sound better at low to mid volumes with the bass? B&O tells me its the “outdated” Airport express and I need to jump to the Core which has a better DAC….

[trackbeo]

Stefano A Barbier wrote:

B&O tells me its the “outdated” Airport express and I need to jump to the Core which has a better DAC….

That’s funny stuff!  They should send first-level support back to wherever they did stand-up comedy routines before pretending to work at an audio company.

Instead, in 2.1 mode, turn off the 19’s LPF and flip its phase switch.  (Maybe this isn’t your problem, but it’s trivial to test.) In theory, a sub’s bass in the opposite phase would cancel out the main speaker’s bass, and you’d notice decreased bass until such volume as you totally overwhelmed it with the opposite phase.  Fits your description!  This also corresponds to your result with the double low-pass filtering, because LPF control will alter the output phase.  (Type as a question into your favorite search engine and look at the resulting diagrams or videos for an explanation.)  As a second-order tweak, because phase ~= delay at low frequencies, you could experiment moving the 19 closer to or further from your listening position than the 18s.  Alas, moving also messes with distance from whatever wall or corner you have placed 19 beside, further increasing or decreasing bass from room gain.

(Caveat: I also use 18s and 19, but daisy-chained with wired Powerlink cables, and no Transmitter 1.  Adjusting the LPF, gain, and location of the 19 was a pain, in part because I didn’t do the time-tested method of seating the 19 in my listening chair and crawling around the floor to listen for the maximum output point.  Why not?  Locations were “constrained by where it looks good”.  My loss.)

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