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

[Duke]

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.

Is this response an AI-generated cut-and-paste? If so, PLEASE identify it as such.

Do you know what happens to BL when the voice coil resistance is changed?

If you use the exact same motor and replace an 8-ohm voice coil with a 16-ohm voice coil, the BL is INCREASED by a factor of the square root of two. Or if you replace the 8-ohm voice coil with a 4-ohm voice coil, the BL is REDUCED by a factor of the square root of two.

In neither case has the actual motor strength changed! So if you ONLY look at BL, you would think the 16-ohm woofer's motor is TWICE as strong as the 4-ohm woofer's motor. But that would be COMPLETELY WRONG.

THAT is why you have to do the extra math to calculate BL^2/Re, IF you want to do an apples-to-apples comparison of different woofers.

 

[Snickers-is]

​

BxL is the backbone of mid-bass performance because:

1. It directly sets cone acceleration (a=BL⋅I/ma=BL⋅I/m).

This still does not correlate to sound quality.

1. It governs damping and distortion via BL(x)BL(x) linearity.

Bl(x) is not the same as Bl. This has nothing to do with the statement we are discussing.

1. Industry data (Klippel, AES) proves its dominance in HD reduction.

No it does not. This is up to you to prove.

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.

Midbass quality comes mainly from having a flat Bl(x,i). Increasing Bl does not affect the sound quality directly.

 

[Snickers-is]

THAT is why you have to do the extra math to calculate BL^2/Re, IF you want to do an apples-to-apples comparison of different woofers.

Another way to illustrate this is by connecting two drivers in parallel. The current is then divided between the two drivers and so is the force, meaning the Bl is unchanged. But the mass is double and Sq would typically improve.

But I think it is important to point out that even if one uses the Bl squared over resistance, the value still has no direct effect on how precisely the driver can reproduce a signal.

 

[LSPhil]

Is this response an AI-generated cut-and-paste? If so, PLEASE identify it as such.

Do you know what happens to BL when the voice coil resistance is changed?

If you use the exact same motor and replace an 8-ohm voice coil with a 16-ohm voice coil, the BL is INCREASED by a factor of the square root of two. Or if you replace the 8-ohm voice coil with a 4-ohm voice coil, the BL is REDUCED by a factor of the square root of two.

In neither case has the actual motor strength changed! So if you ONLY look at BL, you would think the 16-ohm woofer's motor is TWICE as strong as the 4-ohm woofer's motor. But that would be COMPLETELY WRONG.

THAT is why you have to do the extra math to calculate BL^2/Re, IF you want to do an apples-to-apples comparison of different woofers.

I’m talking about precision; you’re talking about maximum loudness. I’m not convinced that a PA driver is better than the best Scan-Speak midrange out there. Let’s agree to disagree

 

[Matt_Holland]

If you compared subjective SQ between two drivers with different B, but otherwise same Re, cone mass, size and suspension, in the same enclosure, the driver with the lower B would have less damping and a higher group delay (worse transient response).

Similarly, keeping all parameters the same except cone mass would lead to the same difference in group delay. The lower mass cone would have less group delay and better transient response.

@LSPhil are you talking about the driver/enclosure combination?

 

[Duke]

I’m talking about precision; you’re talking about maximum loudness. I’m not convinced that a PA driver is better than the best Scan-Speak midrange out there. Let’s agree to disagree

No, I'm talking about real-world motor strength (BL^2/Re), which is a FACTOR in maximum loudness, but in and of itself it is NOT the predictor of maximum loudness.

Likewise BL is a FACTOR in precision, but in and of itself it is NOT the predictor of precision.

Ime (been doing this professionally for two decades) BL^2/(Re x MMS) is one of several predictors of precision.

I'm okay with agreeing to disagree, but please read my post #541 because it speaks to the fallacy of focusing ONLY on BL and NOT taking voice coil resistance into account.

 

[Snickers-is]

If you compared subjective SQ between two drivers with different B, but otherwise same Re, cone mass, size and suspension, in the same enclosure, the driver with the lower B would have less damping and a higher group delay (worse transient response).

Similarly, keeping all parameters the same except cone mass would lead to the same difference in group delay. The lower mass cone would have less group delay and better transient response.

@LSPhil are you talking about the driver/enclosure combination?

It is risky to draw conclusions based on a test like that. There are other differences that you overlook here. Is is too easy to just stick with what seems to conform with pre-existing myths.

 

[Snickers-is]

I’m not convinced that a PA driver is better than the best Scan-Speak midrange out there.

For the application, there are no current Scan Speak drivers that can match the transient response and intermodulation distortion. These are interconnected, and they are derived from the deviation in the permanent magnetic field from rest.

In other words, the key is to modulate the Bl as little as possible within the working range of the driver for the given application.

The relationships between acoustic impedance, Re, Bl, efficiency, moving mass, stability of the magnetic circuit, the ability for the driver to get rid of heat and how the mass is distributed within the moving parts are all key elements for mid-bass performance as long as you consider them all at the same time. Picking on a single parameter is simply not a valid case.

The driver that was selected happen to have excellent performance for that specific application based on the parameters mentioned. There are currently no "hifi" drivers that can match this performance.

That is why this speaker also excels so completely off the scale on mid bass performance. At least that is what the experienced studio people that reviewed them said.

 

[LSPhil]

BxL ≈ Transconductance (electricity)(Current-to-Force conversion).

BxL2/Re ≈ Power Transfer Efficiency (Electrical to Mechanical).

 

[SigbergAudio]

I’m talking about precision; you’re talking about maximum loudness. I’m not convinced that a PA driver is better than the best Scan-Speak midrange out there. Let’s agree to disagree

We purchase directly from Scan-Speak for our subwoofer drivers, so it would be no problem to use a Scan-Speak driver, if one was better suited.

Let me also remind you that we are talking about a midbass driver. The Manta has a separate 5.5" midrange driver (It's a 4-way system).

 

[Snickers-is]

Transconductance is conversion from a voltage signal to current. The biggest contributor to deviation there is Le(x,i). As this is a parameter that is extremely signal dependent and prone to hysteresis effects it is hard to determine it accurately. That is why saturated motors and shorting rings have such huge effect on sound quality.

 

[Matt_Holland]

It is risky to draw conclusions based on a test like that. There are other differences that you overlook here. Is is to easy to just stick with what seems to conform with pre-existing myths.

If all parameters are the same except either magnet strength or cone mass, would the resulting damping of the driver/enclosure combination not be higher for both the higher magnet strength and lower cone mass cases? Does higher damping result in more accurate reproduction assuming other factors such as frequency response and distortion don’t dominate?

 

[Snickers-is]

If all parameters are the same except either magnet strength or cone mass, would the resulting damping of the driver/enclosure combination not be higher for both the higher magnet strength and lower cone mass cases?

You touched on this in your previous post as well, and you mentioned group delay. Firstly, that group delay in the bass region is relatively audible is a myth. But secondly, if you optimize a driver for a given box and double the mass, you will typically get an increase in group delay due to the increase in reactive components dominance over pass band output (resistive components). But like in the Manta, where there is an open baffle, the difference in group delay might even go the other way since the resonant frequency goes down without a significant opposing capacitance.

Does higher damping result in more accurate reproduction assuming other factors such as frequency response and distortion don’t dominate?

No, in some cases, current drive will lower the distortion significantly. This is quite common for a lot of vintage drivers.

 

[MAB]

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.

You focused on the effective mass of the driver. It's just one part of the equation. And for whatever reason, you and/or ChatGPT got it wrong from the outset:

PA drivers are optimized for high output and power handling, not forfine microdynamics or low-level linearity. Their heavier moving mass,

You keep saying that 'PA drivers' have heavier moving mass, this is untrue. You compare 'PA drivers' to Seas and Scan Speak several times. Putting aside you got the driver used in this speaker wrong, and Seas doesn't make a 12" midrange, or even woofer... Typical HiFi drivers are much lower Mms than a typical PA driver, if a generalization is to be made. I have data on nearly 200 12" PA drivers. Here is that data compared to some Scan Speak and a Visaton 12" driver:

12" Driver Manufacturer	Group	# of drivers with data	Average Mms (g)
B&C Speakers	12 Inch 'PA driver'	16​	80​
Beyma	12 Inch 'PA driver'	21​	65​
BMS	12 Inch 'PA driver'	10​	88​
Eighteen Sound	12 Inch 'PA driver'	22​	57​
Eminence	12 Inch 'PA driver'	22​	64​
FaitalPRO	12 Inch 'PA driver'	14​	82​
Fane	12 Inch 'PA driver'	26​	44​
JBL	12 Inch 'PA driver'	51​	57​
Scan-Speak	12 Inch 'HiFi driver'	4​	128​
Visaton	TIW300	1​	92​

The average 'PA driver' has about half the Mms as a typical Scan Speak 'HiFi driver' of similar Sd. Looking at 10" drivers yields the same results, can be extended to many more 'HiFi driver' brands. I leave it to you to explore. I do wonder how ChatGPT can even get lists of published parameters wrong... That is for another day.

Mms by itself is not enough, don't want to focus on that alone, but you keep saying factually incorrect things in addition to this. Looks like a chatbot led you astray here. Perhaps take a deep breath, step back, and listen to some people here who trying to set you right. People aren't trying to provoke you, they are trying to unwind the incorrect statements you are making.

 

[SigbergAudio]

You focused on the effective mass of the driver. It's just one part of the equation. And for whatever reason, you and/or ChatGPT got it wrong from the outset:

You keep saying that 'PA drivers' have heavier moving mass, this is untrue. You compare 'PA drivers' to Seas and Scan Speak several times. Putting aside you got the driver used in this speaker wrong, and Seas doesn't make a 12" midrange, or even woofer... Typical HiFi drivers are much lower Mms than a typical PA driver, if a generalization is to be made. I have data on nearly 200 12" PA drivers. Here is that data compared to some Scan Speak and a Visaton 12" driver:

12" Driver Manufacturer	Group	# of drivers with data	Average Mms (g)
B&C Speakers	12 Inch 'PA driver'	16​	80​
Beyma	12 Inch 'PA driver'	21​	65​
BMS	12 Inch 'PA driver'	10​	88​
Eighteen Sound	12 Inch 'PA driver'	22​	57​
Eminence	12 Inch 'PA driver'	22​	64​
FaitalPRO	12 Inch 'PA driver'	14​	82​
Fane	12 Inch 'PA driver'	26​	44​
JBL	12 Inch 'PA driver'	51​	57​
Scan-Speak	12 Inch 'HiFi driver'	4​	128​
Visaton	TIW300	1​	92​

The average 'PA driver' has about half the Mms as a typical Scan Speak 'HiFi driver' of similar Sd. Looking at 10" drivers yields the same results, can be extended to many more 'HiFi driver' brands. I leave it to you to explore. I do wonder how ChatGPT can even get lists of published parameters wrong... That is for another day.

Mms by itself is not enough, don't want to focus on that alone, but you keep saying factually incorrect things in addition to this. Looks like a chatbot led you astray here. Perhaps take a deep breath, step back, and listen to some people here who trying to set you right. People aren't trying to provoke you, they are trying to unwind the incorrect statements you are making.

In Scan-Speak's "defense", the only 12" drivers they have are subwoofer drivers, which will typically end up with low sensitivity and high mms. While on average the PA manufacturers will to a greater extent have woofers and midwoofers, which will naturally have lower mms.

And that is sort of the point. There's nothing wrong with the Scan-Speak 12" drivers, they're simply not designed for this purpose. A dedicated midbass driver is relatively rare in hifi, so the hifi manufacturers do not provide them.

While the driver we have chosen is designed for this purpose, with a much higher sensitivity, lower mms, higher fs, powerful motor, etc etc - in conclusion a very suitable driver for this application, where it is operating between 100 and 600hz.

 

[MAB]

In Scan-Speak's "defense", the only 12" drivers they have are subwoofer drivers, which will typically end up with low sensitivity and high mms. While on average the PA manufacturers will to a greater extent have woofers and midwoofers, which will naturally have lower mms.

And that is sort of the point. There's nothing wrong with the Scan-Speak 12" drivers, they're simply not designed for this purpose. A dedicated midbass driver is relatively rare in hifi, so the hifi manufacturers do not provide them.

While the driver we have chosen are designed for this purpose, with a much higher sensitivity, lower mms, higher fs, powerful motor, etc etc - in conclusion a very suitable driver for this application, where it is operating between 100 and 600hz.

Agree.
Nothing wrong with Scan Speak. Or Seas.
Also nothing wrong with high or low Mms. Or PA vs. HiFi drivers, however that distinction is made.
It's the application of the drivers, which I think you have explained well.

 

[Curvature]

purely mathematical consideration

Not objective, then.

The correct word is speculative.

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.

Read this paper, where the authors tested such claims by attaching weights to the dust cap.

 

[LSPhil]

Not objective, then.

The correct word is speculative.

Read this paper, where the authors tested such claims by attaching weights to the dust cap.

After reading, I’ve chosen not to debate this further. It seems that in your view, factors like membrane material, diaphragm weight, and BxL are irrelevant. I respectfully disagree, but I’ll leave it at that.

 

[Snickers-is]

After reading, I’ve chosen not to debate this further. It seems that in your view, factors like membrane material, diaphragm weight, and BxL are irrelevant. I respectfully disagree, but I’ll leave it at that.

None ever said any of that in this debate.

 

[SigbergAudio]

More to come, but an early glimpse into a private home theater still in progress in Milan, Italy. Will be used for both music and movies.

Sigberg Audio Manta as main speakers, with 2x Sigberg Audio Inkognito subwoofers + also two Arendal 2S that the customers had already). There's also a Sigberg Audio SBS.1 as center channel behind the screen.

None of the subs are in their final location, this is a pic taken during initial setup just to see that everything works. Pic is a bit dark / grainy since the room has no windows. Custom stands for the Mantas (not the ones that are normally included). 2.6m ceiling. Some acoustic paneling are coming as well.

I think this is going to turn out pretty good.