Development thread: High-end dual opposing 10" subwoofer: Sigberg Audio 10D

[sigbergaudio]

Lately I've been experimenting with the combination of high pass and limiter to see if we can safely bring out more infrasonics from our subwoofers, which should theoretically be possible. And luckily in practice as well.

This is the old and new configuration measured nearfield:
View attachment 435467


And here is how it translates to in-room response (measurement in the listening position of a 20m^2 room:
(Note that this room has a dip at 15hz, that's why the response goes first down and then up again)
View attachment 435470


So pretty significant change between 10-20hz, for those who worry about movies or pipe organs. The area around 40-45hz is a peak that I haven't damped fully, so I would say it's fair to say the reference level is 85dB here. The rest of the spectrum would typically be at 77-80dB depending on how much of a house curve you have. That means the sub is pretty much flat to 20hz in-room, and -6dB is around 16.5hz, and in part due to the dip at 15hz. We're still only at around -10dB at 10hz due to room gain, or -3/-5dB if referenced to the rest of the frequency range.

But can you play loud? Everything is relative, but in this room a single 10D is at around 8.7% THD at 20hz/100dB measured from the listening position. This is a position where the sub is around 50cm from any wall and not close to any corner, so limited room gain as well.

After some further testing I've concluded that this was a little bit aggressive. If we are to keep this, we have to tune the limiter so that we lose some of that upper bass (40hz and up) punch that these subs are really good at, so the updated production tuning will be somewhere in the middle of these two graphs.

 

[Vacceo]

After some further testing I've concluded that this was a little bit aggressive. If we are to keep this, we have to tune the limiter so that we lose some of that upper bass (40hz and up) punch that these subs are really good at, so the updated production tuning will be somewhere in the middle of these two graphs.

Room gain and corner loading could probably enhance the performance, so no need to push it to the limit.

 

[sigbergaudio]

Measurement at a customer, 30m^2 living room with a single 10D almost in the middle of the front wall (paired with our SBS.1 speakers).

Pretty decent extension, I don't think most people can expect this, but lucky room and placement I guess. Also pretty even / not a lot of dips to be only a single sub.