Sigberg Audio Manta (12" wideband cardioid active speakers) development thread

[Matt_Holland]

No intent to derail thread topic at hand, but just to mention … Was unaware of this K-array design. Very interesting, thanks for the link @Matt_Holland

I’d be delighted to discuss anything related to the brand by message. I work for the UK distributor.

 

[Grimoire]

I’d be delighted to discuss anything related to the brand by message. I work for the UK distributor.

Why not start a new thread and tell us all about them? I find the idea intriguing but the site confusing.

 

[Duke]

The woofer we’re discussing has a fairly heavy diaphragm (around 50 g), and to reach about 80 dB(A), it operates at approximately 33 mW in my estimation, its inertia is already critically high.

Looking at the moving mass in isolation is insufficient for drawing any conclusions.

You have to look at the effective motor strength too, which is BL^2/Re. Then look at the motor-strength-to-moving-mass ratio. Then look at where the crossover frequencies are. With all of this information you could make a comparison between different speakers regarding the motor-strength-to-moving-mass ratios in the different frequency regions. This would arguably be of some relevance, but imo there are other things which matter a lot more.

From my point of view, the manufacturer wanted to develop a system with narrower dispersion characteristics, specifically tailored for room radiation.

Imo @sigbergaudio has chosen to address the real-world problems that matter most, and it looks to me like he has done so in ways which do not introduce compromises in other areas.

 

[LSPhil]

Looking at the moving mass in isolation is insufficient for drawing any conclusions.

You have to look at the effective motor strength too, which is BL^2/Re. Then look at the motor-strength-to-moving-mass ratio. Then look at where the crossover frequencies are. With all of this information you could make a comparison between different speakers regarding the motor-strength-to-moving-mass ratios in the different frequency regions. This would arguably be of some relevance, but imo there are other things which matter a lot more.



Imo @sigbergaudio has chosen to address the real-world problems that matter most, and it looks to me like he has done so in ways which do not introduce compromises in other areas.

Here you see two diagrams:
1. Top: The sinusoidal driving forceF(t), as it might originate from a music signal.
2. Bottom: The resulting displacementof the membrane x(t) in millimeters, showing how the membrane movesunder the influence of this force.
You can observe:
The membrane follows the force withsome delay and damping.
The motion is sluggish (due to the massmm) and not immediately identical to the force profile.
The damping ensures that the membranedoes not oscillate infinitely.

 

[SigbergAudio]

View attachment 461693

Here you see two diagrams:
1. Top: The sinusoidal driving forceF(t), as it might originate from a music signal.
2. Bottom: The resulting displacementof the membrane x(t) in millimeters, showing how the membrane movesunder the influence of this force.
You can observe:
The membrane follows the force withsome delay and damping.
The motion is sluggish (due to the massmm) and not immediately identical to the force profile.
The damping ensures that the membranedoes not oscillate infinitely.

This is completely generic. It feels like you have an assumption that the larger the driver the worse it is, nothing else considered. This is of course not true.

I am completely open to fair criticism in this thread, but you need to keep it both relevant to the products and back things up with facts, not just claims and assumptions.

The 12" driver used in the Manta is rated at over 96dB sensitivity, and it maintains over 94dB within the entire frequency range it is used in the Manta. This means it needs less power to reproduce any given SPL than most much smaller drivers, not more. This may sound counter-intuitive, but it still true.

Please stop spreading FUD (Fear, Uncertainty and Doubt) above this speaker's ability to be precise or play well at low volume, as it is just not grounded in facts. You are assuming things based on I-dont-know-what from the PA world, but this is not a PA speaker.

The Manta was designed from the ground up to be used in studios and consumer spaces (people's homes), so of course it is designed to work well at moderate levels - anything else would be stupid. I am not stupid.

 

[LSPhil]

This is completely generic. It feels like you have an assumption that the larger the driver the worse it is, nothing else considered. This is of course not true.

I am completely open to fair criticism in this thread, but you need to keep it both relevant to the products and back things up with facts, not just claims and assumptions.

The 12" driver used in the Manta is rated at over 96dB sensitivity, and it maintains over 94dB within the entire frequency range it is used in the Manta. This means it needs less power to reproduce any given SPL than most much smaller drivers, not more. This may sound counter-intuitive, but it still true.

Please stop spreading FUD (Fear, Uncertainty and Doubt) above this speaker's ability to be precise or play well at low volume, as it is just not grounded in facts. You are assuming things based on I-dont-know-what from the PA world, but this is not a PA speaker.

The Manta was designed from the ground up to be used in studios and consumer spaces (people's homes), so of course it is designed to work well at moderate levels - anything else would be stupid. I am not stupid.

I’m glad you’ve found a midwoofer with 96dB sensitivity that’s as precise at 33mW as the rest of the HiFi drivers. I was asked here to provide evidence, and I did—unlike others who resorted to insults, calling me 'stupid' while offering nothing but repeated opinions and unsubstantiated claims. I approach things objectively, and if someone can prove me wrong, I’m fully capable of correcting myself.
I’m genuinely impressed by drivers like your midwoofer, though it does make me wonder why other manufacturers haven’t replicated it. If you say your speaker is different, I have no choice but to take your word for it. I won’t engage further unless provoked, as I’d prefer to leave things here.

 

[Matt_Holland]

View attachment 461693

Here you see two diagrams:
1. Top: The sinusoidal driving forceF(t), as it might originate from a music signal.
2. Bottom: The resulting displacementof the membrane x(t) in millimeters, showing how the membrane movesunder the influence of this force.
You can observe:
The membrane follows the force withsome delay and damping.
The motion is sluggish (due to the massmm) and not immediately identical to the force profile.
The damping ensures that the membranedoes not oscillate infinitely.

It would be good to know the source of this data, and what driver the measurements are from. As @sigbergaudio pointed out, it looks generic, so to put your argument into context, I would like to see similar graphs for a range of different drive unit sizes.

 

[Curvature]

View attachment 461693

Here you see two diagrams:
1. Top: The sinusoidal driving forceF(t), as it might originate from a music signal.
2. Bottom: The resulting displacementof the membrane x(t) in millimeters, showing how the membrane movesunder the influence of this force.
You can observe:
The membrane follows the force withsome delay and damping.
The motion is sluggish (due to the massmm) and not immediately identical to the force profile.
The damping ensures that the membranedoes not oscillate infinitely.

Any significant ringing or damping issues would show up in the frequency response.

 

[Duke]

It would be good to know the source of this data, and what driver the measurements are from. As @sigbergaudio pointed out, it looks generic, so to put your argument into context, I would like to see similar graphs for a range of different drive unit sizes.

I would guess that the specifics matter very much... the specifics including motor strength, inductance, suspension system compliance, electrical and mechanical Q, moving mass, cone area, linear excursion, and flux linearity.

 

[LSPhil]

It would be good to know the source of this data, and what driver the measurements are from. As @sigbergaudio pointed out, it looks generic, so to put your argument into context, I would like to see similar graphs for a range of different drive unit sizes.

This is a purely mathematicalconsideration thatdescribes the relationship between the movingmass and theapplied voltage(or force), independentof frequency.
Above a certain currentor driving force,the inertia of themoving mass beginsto follow the input drive (acceleration becomes significant).
For example:

• A Scan-Speak 18M driver with a moving mass of 13 g has a Bl product (force factor) of 6.5 N/A.
  
• In comparison, a 12-inch PA driver with a moving mass of 50 g has a Bl of only 14.5 N/A.

However, basedon the proportional relationshipbetween force and mass, the PA driver shouldhave a Bl of at least 25 N/Ain order to move the heavier membrane with similar dynamic response(i.e., to maintain the same acceleration for a larger mass).
If the Bl is too low relative tothe mass, the system becomes dynamically limited — and increasingBl to 25 N/A would inevitably affectother TSPs (Thiele-Small parameters)like Qes, sensitivity, and possibly fs.

 

[Snickers-is]

This is a purely mathematicalconsideration thatdescribes the relationship between the movingmass and theapplied voltage(or force), independentof frequency.
Above a certain currentor driving force,the inertia of themoving mass beginsto follow the input drive (acceleration becomes significant).
For example:

• A Scan-Speak 18M driver with a moving mass of 13 g has a Bl product (force factor) of 6.5 N/A.
  
• In comparison, a 12-inch PA driver with a moving mass of 50 g has a Bl of only 14.5 N/A.

However, basedon the proportional relationshipbetween force and mass, the PA driver shouldhave a Bl of at least 25 N/Ain order to move the heavier membrane with similar dynamic response(i.e., to maintain the same acceleration for a larger mass).
If the Bl is too low relative tothe mass, the system becomes dynamically limited — and increasingBl to 25 N/A would inevitably affectother TSPs (Thiele-Small parameters)like Qes, sensitivity, and possibly fs.

Can you prove that Bl actually affects the mid bass performance at all?

I mean, I can think of lots of things that makes the above statements very misleading. It really starts with pondering the implications of Bl directly affecting sound quality.

 

[LSPhil]

Can you prove that Bl actually affects the mid bass performance at all?

I mean, I can think of lots of things that makes the above statements very misleading. It really starts with pondering the implications of Bl directly affecting sound quality.

A practical example from everyday life helps illustrate this: cars – the analogy fits perfectly.

• A weak engine (the motor force) combined with a heavy car (high mass) results in sluggish performance and poor dynamics.
• A powerful engine paired with an optimized weight gives you precise and responsive acceleration — just like in high-performance vehicles

The art of loudspeaker design lies in balancing:

1. F – the driving force (analogous to engine torque
2. m – the moving mass (vehicle weight),
3. k – the suspension stiffness (spring constant),

— just like in automotive tuning!


Getting this balance right is key to achieving accurate, dynamic, and controlled signal reproduction.

 

[Snickers-is]

It is just that your example is not relevant. It is a classical salesman pitch implying that more Bl gives more speed and thus more precision.

In the real world, the driver does not create excursions as a direct product of the signal amplitude, it creates acceleration. The amount of acceleration is directly proportional to the sound pressure.

If your statement had any truth to it, that would mean only the strongest transients would be reproduced reasonably accurate, while weaker transients would be reproduced proportionally less accurate. What we measure (and hear) is quite the opposite.

 

[Duke]

This is a purely mathematical consideration that describes the relationship between the moving mass and the applied voltage(or force), independent of frequency...

For example:

• A Scan-Speak 18M driver with a moving mass of 13 g has a Bl product (force factor) of 6.5 N/A.
• In comparison, a 12-inch PA driver with a moving mass of 50 g has a Bl of only 14.5 N/A.

In order to make an apples-to-apples comparison of the motor force applied to the voice coil for a given voltage input, BL is an inadequate metric.

The correct metric would be BL^2/Re, which takes the driver's DC resistance into account.

Using your numbers for the Scan-Speak driver and assuming a 6 ohm DC resistance, BL^2/Re = 7.04. Dividing that by cone mass to get the motor-strength-to-moving-mass ratio, we get .54

Using your numbers for the 12" PA driver, and assuming a 6 ohm DC resistance, BL^2/Re = 35.04. Dividing that by cone mass to get the motor-strength-to-moving-mass ratio, we get .70.

Therefore, for a given voltage input, the PA driver in your example has a HIGHER motor-strength-to-moving-mass ratio than the Scan-Speak driver.

 

[LSPhil]

BxL isn’t just a "spec"—it’s the backbone of mid-bass performance. Ignoring it is like saying "Horsepower doesn’t affect lap times." Sure, tires and weight matter, but without force, you’re going nowhere.
Next time someone questions BxL’s importance, ask them:

1. Why do all high-end woofers prioritize BxL linearity?
2. Why does distortion spike when BxL collapses at high excursion?
3. Why do damping factor specs exist?

The answers all point back to BxL. Physics doesn’t lie.

 

[Snickers-is]

BxL isn’t just a "spec"—it’s the backbone of mid-bass performance. Ignoring it is like saying "Horsepower doesn’t affect lap times." Sure, tires and weight matter, but without force, you’re going nowhere.
Next time someone questions BxL’s importance, ask them:

1. Why do all high-end woofers prioritize BxL linearity?
2. Why does distortion spike when BxL collapses at high excursion?
3. Why do damping factor specs exist?

The answers all point back to BxL. Physics doesn’t lie.

Not a single one of your points has anything to do with the amount of Bl you have to begin with.

What is your proof of Bl being "the back bone of mid-bass performance"?

 

[LSPhil]

1. BL2/ReBL2/Re tells you “how loud it can get per watt.”
2. BLBL tells you “how accurately the cone tracks the signal.”
3. Both metrics matter—but for different goals.

• BL is about control.
• BL2/ReBL2/Re is about raw power.
• Both metrics matter—but their importance depends on the application.

 

[Snickers-is]

View attachment 461693

Here you see two diagrams:
1. Top: The sinusoidal driving forceF(t), as it might originate from a music signal.
2. Bottom: The resulting displacementof the membrane x(t) in millimeters, showing how the membrane movesunder the influence of this force.
You can observe:
The membrane follows the force withsome delay and damping.
The motion is sluggish (due to the massmm) and not immediately identical to the force profile.
The damping ensures that the membranedoes not oscillate infinitely.

This is such immature understanding of the topic. The signal is NOT proportional to the cone position, and it is NOT proportional to the cone speed.

I appreciate you asking, but stating that something is bad, just because you have no real understanding of the topic you are lecturing others about is not helpful for anyone else than competitors that sell their products based on the same faulty narrative.

But I would personally avoid any product from any manufacturer that does not have a clue what they are talking about.

I suggest you hear the product in question. I have heard it many times, and it is hard to think of a competitor anywhere close in price.

 

[Snickers-is]

1. BL2/ReBL2/Re tells you “how loud it can get per watt.”

Incorrect

1. BLBL tells you “how accurately the cone tracks the signal.”

Incorrect

• BL is about control.

Incorrect

• BL2/ReBL2/Re is about raw power.

Incorrect

 

[LSPhil]

Not a single one of your points has anything to do with the amount of Bl you have to begin with.

What is your proof of Bl being "the back bone of mid-bass performance"?

​

BxL is the backbone of mid-bass performance because:

1. It directly sets cone acceleration (a=BL⋅I/ma=BL⋅I/m).
2. It governs damping and distortion via BL(x)BL(x) linearity.
3. Industry data (Klippel, AES) proves its dominance in HD reduction.

Your turn: If you have specific driver measurements showing BxL doesn’t correlate with mid-bass quality, let’s analyze them. Otherwise, the physics and data stand.