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.

 

[David_M]

Continuation from here. I confused two reviews One measured the impulse response. Another bought the review sample (with wife's permission).

The Rhythmik F18 (Sealed, 900W) direct servo was the sub in question whose impulse response (IR) was measured here.

The reviewer who bought the review sample of the 'smaller' F15-V (vented or ported) was from Sound-and Vision Magazine. His conclusions were "Rythmik’s direct servo technology isn’t a marketing slogan—it provides the most precise bass these ears have ever heard .... I've been in bass heaven since employing two of these subs, and now the real fun begins—convincing the person who must not be crossed(aka, the wife) that they need to be a permanent fixture in our theater. Wish me luck!".

Yet a 3rd (and interesting) reviewer, from YouTube, Nemo Propaganda, divides subs into two categories. SPL/LFE subs (SVS and many others) and SQ subs (like Rhythmik). He reviewed the F18 here. He noted something I've never heard before ... note-to-note distinction. An SPL/LFE sub will mush 30Hz and 35Hz signals together as one giant note, for example. An SQ sub will reveal those 30Hz and 35Hz signals as two distinct notes. I find this, along with low distortion, extremely attractive traits to look for in a subwoofer. If one requires more SPL, then buy more SQ subs, then you get the best of both worlds .

I believe you should include IR tests as part of your design validation process, if you don't already ... and I apologize for polluting your thread with a competitor's product.

As you've said before, you make SQ subs, designed for music and not SPL/LFE subs. Have you measured IR plots for the 10D or Incognito?

 

[sigbergaudio]

Continuation from here. I confused two reviews One measured the impulse response. Another bought the review sample (with wife's permission).

The Rhythmik F18 (Sealed, 900W) direct servo was the sub in question whose impulse response (IR) was measured here.

View attachment 507108

The reviewer who bought the review sample of the 'smaller' F15-V (vented or ported) was from Sound-and Vision Magazine. His conclusions were "Rythmik’s direct servo technology isn’t a marketing slogan—it provides the most precise bass these ears have ever heard .... I've been in bass heaven since employing two of these subs, and now the real fun begins—convincing the person who must not be crossed(aka, the wife) that they need to be a permanent fixture in our theater. Wish me luck!".

Yet a 3rd (and interesting) reviewer, from YouTube, Nemo Propaganda, divides subs into two categories. SPL/LFE subs (SVS and many others) and SQ subs (like Rhythmik). He reviewed the F18 here. He noted something I've never heard before ... note-to-note distinction. An SPL/LFE sub will mush 30Hz and 35Hz signals together as one giant note, for example. An SQ sub will reveal those 30Hz and 35Hz signals as two distinct notes. I find this, along with low distortion, extremely attractive traits to look for in a subwoofer. If one requires more SPL, then buy more SQ subs, then you get the best of both worlds .

I believe you should include IR tests as part of your design validation process, if you don't already ... and I apologize for polluting your thread with a competitor's product.

As you've said before, you make SQ subs, designed for music and not SPL/LFE subs. Have you measured IR plots for the 10D or Incognito?

Nemo has reviewed the 10D as well, and discusses both the note-to-note distinction and the SPL vs SQ scale in relation to the 10D:

I don't have any impulse response graphs similar to that to share at this time.

 

[David_M]

Nemo has reviewed the 10D as well, and discusses both the note-to-note distinction and the SPL vs SQ scale in relation to the 10D:

I don't have any impulse response graphs similar to that to share at this time.

Does the 10D, being dual opposed, cancel out even order harmonics to reduce distortion further, or is it to brace the amp from moving about the room during high spl peaks?

 

[sigbergaudio]

Does the 10D, being dual opposed, cancel out even order harmonics to reduce distortion further, or is it to brace the amp from moving about the room during high spl peaks?

The main effect is to minimize (almost eliminate) any vibration in the cabinet itself, and thus eliminate any cabinet resonance / noise. Such resonances can otherwise turn up as harmonic distortion or even frequency deviations, and is also what is often the true reason why people are able to localize subs.

 

[sigbergaudio]

New review at Home Theater Forum, where it ended up somewhat randomly. Obviously a home theater focused website, used to larger subwoofers - but it got a decent review still.

With a robust build quality and a polished sound, the Sigberg Audio 10D is a compact subwoofer that excels. So small is the 10D that it’s all but invisible in your room, yet it is no shrinking violet. This subwoofer has a smooth, refined quality that belies its modest appearance. And why not, it packs the equivalent of a 15” driver in a cabinet that would make you think only a single 10” could exist inside it.

Sigberg Audio 10D Subwoofer Review

With a robust build quality and a polished sound, the Sigberg Audio 10D is a compact subwoofer that excels.

www.hometheaterforum.com