Understanding subwoofers

[sigbergaudio]

View attachment 458729

But what we are trying to achieve here is to give the cone various properties. Weight, stiffness, break-up modes etc, depending on what the driver is to be used for.

Two drivers made of different materials but with similar properties, operating within their passband, will not sound "like paper" or "like aluminum".

The subwoofer/bass drivers we use are aluminium, the midbass / midrange drivers are paper, and the tweeters in one of our coaxials is a silk dome, while the other is a polymer compression driver.

The reason behind this isn't because I've selected drivers with these specific materials because of their musicality or inherent sound, but because they happened to be the materials the driver manufacturer found to be suitable for the parameters I needed for a particular driver.

So that's what you've got reversed in my opinion. It isn't inherently about the materials, it's about the properties we are trying to achieve with the drivers, and then selecting materials (treated or coated such and such) to achieve that. Again with your 4" midrange driver example, yes they sounded different, but not specifically (and certainly not exclusively) due to the material.

 

[LSPhil]

But what we are trying to achieve here is to give the cone various properties. Weight, stiffness, break-up modes etc, depending on what the driver is to be used for.

I see your point, and I appreciate that you explained it so clearly. Of course, no one is saying that a material alone defines the sound without considering other driver properties. But I think we are closer in agreement than it may seem:
The material is chosen because of the properties it offers—stiffness, damping, mass, break-up behaviour—which all contribute to the acoustic result. In the end, we hear the combination of these properties, but they are inseparable from the material’s nature.
So, when I say that cone material plays a role in musicality or sound character, I mean exactly that: the material’s inherent qualities (and how it is used) help shape the final properties of the driver, and therefore its sound.
DKM says it clearly: “A cone’s material strongly influences the acoustical behaviour and the sound of a loudspeaker.” That doesn’t mean “aluminium always sounds like X” or “paper always sounds like Y” in isolation, but that material choice is a key factor in getting the desired behaviour.
So in the end, maybe it’s just two sides of the same coin — you focus on the target properties, I point out that material choice is one of the foundations for achieving them.

 

[SIY]

View attachment 458729

1.

 

[sigbergaudio]

I see your point, and I appreciate that you explained it so clearly. Of course, no one is saying that a material alone defines the sound without considering other driver properties. But I think we are closer in agreement than it may seem:
The material is chosen because of the properties it offers—stiffness, damping, mass, break-up behaviour—which all contribute to the acoustic result. In the end, we hear the combination of these properties, but they are inseparable from the material’s nature.
So, when I say that cone material plays a role in musicality or sound character, I mean exactly that: the material’s inherent qualities (and how it is used) help shape the final properties of the driver, and therefore its sound.
DKM says it clearly: “A cone’s material strongly influences the acoustical behaviour and the sound of a loudspeaker.” That doesn’t mean “aluminium always sounds like X” or “paper always sounds like Y” in isolation, but that material choice is a key factor in getting the desired behaviour.
So in the end, maybe it’s just two sides of the same coin — you focus on the target properties, I point out that material choice is one of the foundations for achieving them.

Yes. So the only thing I'm trying to avoid someone taking away from this is that one material is inherently better or worse. It depends on the application and the goal of the driver. A very high end driver can be made with a paper cone for instance. You don't need "magic" materials developed by NASA.

 

[SIY]

Yes. So the only thing I'm trying to avoid someone taking away from this is that one material is inherently better or worse. It depends on the application and the goal of the driver. A very high end driver can be made with a paper cone for instance. You don't need "magic" materials developed by NASA.

Key for a sub is that we're working in the pistonic range.

 

[sigbergaudio]

Key for a sub is that we're working in the pistonic range.

I was commenting in general terms for a driver (since that's where the thread apparently ended up), not a subwoofer driver specifically.

 

[SIY]

I was commenting in general terms for a driver (since that's where the thread apparently ended up), not a subwoofer driver specifically.

I understand what you were getting at, but since there is some... confusion, it's important to qualify statements with respect to the actual topic.

 

[mk05]

As a follow-up of my above post, and just for your reference, especially the actual example of crossover between L&R subwoofers and main SP's woofers,,,

Very recently, I re-checked re-confirmed Fq-SPL of amplifier's SP high-level output into L&R subwoofers, woofers, midranges, tweeters and super tweeters. Furthermore, I also re-checked re-confirmed my preferred Fq-SLP of room air sound at my listening position in my room acoustic environments. Please visit my post #1,009 on my project thread for the details, if you would be interested.
...

This is a bit above my understanding, but will keep bookmarked to reference as I learn more. Thank you!

 

[mk05]

Of course, no one is saying that a material alone defines the sound without considering other driver properties.

I think then, everyone here at ASR is in agreement. Material in itself does not make a difference. It is the conflation/synergies of the properties that is inherent of a material which lend to differences in measurements.

My very unscientific question was that in order to ascertain if there was something else that is unmeasured and unknown to today's science, we would have to make 100% material specific speakers that measure virtually the same. This would have to mean shave down an aluminum cone to behave exactly the same in every known measurement as paper (for example), Titanium vs Flax, etc. Then with blind study, see if a statistically significant amount of people observe a difference between these 100% exactly same measuring speakers made of different materials. Perhaps then we could conclude that there must an undefined measurement in today's audio science?

 

[dualazmak]

Look at that — even the colleague who isn’t exactly my biggest fan just helped prove my point: diaphragm material does matter! Thanks for backing me up, buddy — didn’t see that coming!

Please understand that I was not saying "I heard the difference between ZYLON and Beryllium", but I felt difference between NS-1000 and NS-5000!

Diaphragm of the driver is, yes, one of the factors, but total design is much different for the SP systems; NS-1000 in sealed, NS-5000 is ported, and much difference in their inner acoustic suppression and even the cabinets, as well as much more; my NS-1000 has been converted into fully active configuration but NS-5000 demo system is passive, and so on. furthermore, and importantly, the listening location and room acoustics were much different.

My major point of the post #81 was "in NS-5000, YAMAHA uses ZYLON all the way through woofer, midrange and tweeter"; this would be quite unique and brave approach, I assume.

Just personally and totally subjectively, I like my renovated-into active NS-1000 at my listening room better that the passive demo NS-5000 auditioned at YAMAHA's gorgeous cottage... Nothing more, nothing less. I really would like to bring demo units of NS-5000 (for free!) in my listening room, if possible.

If I would DIY-convert the demo units of NS-5000 into fully active configuration by bypassing all the passive LC(R)-network, however, YAMAHA will definitely charge me the full price and/or will sue me...

 

[dualazmak]

...
...
... Then with blind study, see if a statistically significant amount of people observe a difference between these 100% exactly same measuring speakers made of different materials. Perhaps then we could conclude that there must an undefined measurement in today's audio science?

At least I myself, assume/believe many of us will easily hear the difference attributable to the diaphragm material... And the like/dislike would be greatly dependent on personal preferences.

 

[LSPhil]

I think then, everyone here at ASR is in agreement. Material in itself does not make a difference. It is the conflation/synergies of the properties that is inherent of a material which lend to differences in measurements.

My very unscientific question was that in order to ascertain if there was something else that is unmeasured and unknown to today's science, we would have to make 100% material specific speakers that measure virtually the same. This would have to mean shave down an aluminum cone to behave exactly the same in every known measurement as paper (for example), Titanium vs Flax, etc. Then with blind study, see if a statistically significant amount of people observe a difference between these 100% exactly same measuring speakers made of different materials. Perhaps then we could conclude that there must an undefined measurement in today's audio science?

Zylon® – ultimate control and breathtaking speed
Every driver – from the deepest bass to the finest treble – is crafted from Zylon®, an ultra-light, ultra-strong material that responds with astonishing speed and precision. The result is a sound that feels seamlessly coherent, rich in detail, and strikingly natural across the entire frequency spectrum. Experience music in its purest, most captivating form.

 

[dualazmak]

Zylon® – ultimate control and breathtaking speed
Every driver – from the deepest bass to the finest treble – is crafted from Zylon®, an ultra-light, ultra-strong material that responds with astonishing speed and precision. The result is a sound that feels seamlessly coherent, rich in detail, and strikingly natural across the entire frequency spectrum. Experience music in its purest, most captivating form.

That is an interesting and impressive (or not?) marketing wording of YAMAHA!

 

[SIY]

Zylon® – ultimate control and breathtaking speed
Every driver – from the deepest bass to the finest treble – is crafted from Zylon®, an ultra-light, ultra-strong material that responds with astonishing speed and precision. The result is a sound that feels seamlessly coherent, rich in detail, and strikingly natural across the entire frequency spectrum. Experience music in its purest, most captivating form.

Weren't they the robot guys on Battlestar Galactaca?

 

[LSPhil]

Canton​

“Our aluminum diaphragms combine maximum rigidity with low weight – for precise, low-distortion sound reproduction even at high volumes.”
“Ceramic-titanium membranes ensure crystal-clear highs and accurate mids with fine detail resolution.”

---

Bowers & Wilkins​

“Our Continuum™ cone provides an open, neutral sound with smooth breakup characteristics, minimizing abrupt changes in diaphragm behavior.”
“The carbon dome tweeters deliver finely detailed high frequencies with exceptional clarity.”

---

KEF​

“Our Uni-Q drivers with aluminum cones produce a particularly natural, precise sound image and pinpoint imaging.”
“The Z-Flex surround and ventilated voice coil ensure deep, controlled bass without coloration.”

---

Focal​

“Our flax fiber cones offer a warm, natural sound signature with high impulse fidelity.”
“Our pure beryllium tweeters provide extreme detail and exceptionally linear high-frequency response.”

---

Dynaudio​

“Our MSP (Magnesium Silicate Polymer) cones deliver a linear frequency response with outstanding dynamics and controlled resonance behavior.”
“The combination of lightweight voice coil wire and powerful magnet ensures precision and transparency.”

---

If you’d like, I can collect official quotes from the manufacturers’ websites or brochures, with proper links and references. Just tell me which brands or models interest you most!

 

[SIY]

Well, advertising is the best way to understand science. This is known.

 

[LSPhil]

Tworzywo	Moduł Youngschera E (GPa)	Ciepło ρ (g/cm³)	Steifigkeit / Gewicht (E/ρ) (GPa / (g/cm3))
Tytan	~105	~4,5	~23
Aluminium	~70	~2,7	~26
Magnez	~45	~1,7	~26
Grafen (mono-warstwowy)	>1000	~0,002	>500 000 (nur theoretisch im Monolayer!)
Kompozyt włókna węglowego	~ 70–150 (je nach Ausrichtung)	~1,6	~44–94
Kompozyt papierowo-celulozowy	~5–15	~0,5–0,7	~7–20
Ceramika (Al2O3, TiO2 w kolorze)	>300	~3,5–4	~75–85

 

[Geert]

Great. Now calculate the natural frequency of a reinforced paper pulp cone subwoofer driver to show us the internal vibrations below 80 Hz. Or share some vibration measurements for subwoofer drivers made via laser triangulation measurements (with for example the Klippel Scanning Vibrometer). You know, the kind of measurements that are readily available for low-mid drivers.

 

[LSPhil]

Great. Now calculate the natural frequency of a reinforced paper pulp cone subwoofer driver to show us the internal vibrations below 80 Hz. Or share some vibration measurements for subwoofer drivers made via laser triangulation measurements (with for example the Klippel Scanning Vibrometer). You know, the kind of measurements that are readily available for low-mid drivers.

I take a straightforward approach and use the best midrange drivers from Scan-Speak. They have already performed all the necessary measurements, because they do everything right. I’ve shown you that the theory of membrane material “equality” simply doesn’t hold up. One thing is certain: not a single serious manufacturer uses pure paper as a diaphragm material, it’s always either metals or composites with controlled diaphragm thickness.
I even spoke with a representative from Müller, the company that produces these membranes, and asked: which material would be the best? His answer was clear: If we had a perfect material, everyone would be using it. And if you want to build something yourself, use Scan-Speak, because they do everything right.
That’s exactly why I’m cautious when it comes to niche manufacturers. The real question is: what can they do better than the established, reputable companies? Why should we pay such high prices for something we could get for 20% of the cost?

 

[SIY]

I take a straightforward approach and use the best midrange drivers from Scan-Speak.

2.

One thing is certain: not a single serious manufacturer uses pure paper as a diaphragm material

/looks at his JBL subs