May I suggest Surtsey to read and study loudspeaker physics yourself?
The issue is complex, and there is no simple answer to your question. Even your question is complex - you ask about a loudspeaker driver's physics , but refer to what you hear and see from a loudspeaker system (obviously bass-reflex tuned)
Here some info about low bass reproduction https://data-bass.com/#/articles?_k=e4lep1
The issue is complex, and there is no simple answer to your question. Even your question is complex - you ask about a loudspeaker driver's physics , but refer to what you hear and see from a loudspeaker system (obviously bass-reflex tuned)
Here some info about low bass reproduction https://data-bass.com/#/articles?_k=e4lep1
You can always try an 80" driver....
https://www.aia-cinema.com/products/subwoofers/the-80-sub-pro-passive-sealed.html
This isn't a joke by the way, I have heard their 24" subwoofer and its excellent
https://www.aia-cinema.com/products/subwoofers/the-80-sub-pro-passive-sealed.html
This isn't a joke by the way, I have heard their 24" subwoofer and its excellent
I know two people using the EV 30" woofers, one in the original enclosures. Not new manufacture, original they way they were originally designed and built.
Large woofers have their own issues. That's why the industry settled on 18" as a common maximum. 15" was the largest before that - and for good reason.
Hi vacuphile,
Large woofers have their own issues. That's why the industry settled on 18" as a common maximum. 15" was the largest before that - and for good reason.
Hi vacuphile,
The problem with excursion is linearity. Engineering again, it is always a compromise and trade-offs. Power, that's a bad thing. The voice coil heats up and changes all it's characteristics. Forget about any T/S alignment data!
I'm not surprised actually. Bigger has always been a trend in cycles. I guess this is that cycle now.
What folks do not realise is that a larger cone requires a much larger enclosure. Often a correctly sized box and smaller woofer can outperform a large one in an enclosure that is too small ( = not optimum). If that isn't enough, the room has to be large enough to support the low frequencies you're trying to recreate. Most domestic large homes do not fit in this category. Forget the average home!
A similar thing happened in car audio. We used to design systems that sounded fantastic, then someone decided to heck with sound quality and make it loud. The industry just fell apart after than, then I got out of car audio as some of the high end brands also made their exit. As far as I'm concerned, it the end result doesn't perform well, and I mean flat low distortion sound, why bother? What are you doing?
What folks do not realise is that a larger cone requires a much larger enclosure. Often a correctly sized box and smaller woofer can outperform a large one in an enclosure that is too small ( = not optimum). If that isn't enough, the room has to be large enough to support the low frequencies you're trying to recreate. Most domestic large homes do not fit in this category. Forget the average home!
A similar thing happened in car audio. We used to design systems that sounded fantastic, then someone decided to heck with sound quality and make it loud. The industry just fell apart after than, then I got out of car audio as some of the high end brands also made their exit. As far as I'm concerned, it the end result doesn't perform well, and I mean flat low distortion sound, why bother? What are you doing?
Subwoofer design, especially with the motors, has come a long way in the past couple of decades. The 30" EVs are a 1950s era design and it shows. Vanishingly small linear excursion, low power handling, need to be rotated every year to avoid suspension sag because the suspensions were so soft, the styrofoam cones were highly prone to breakup, etc. There is just no comparison against what motors the designers are coming up with and the soft parts now available to build upon them.
These days, bigger drivers can be sourced that outperform smaller drivers. The 24" drivers mentioned tend to have lower distortion at the same output levels than most 18" drivers as can be seen in the results measured and published on Data-bass.com. One of the lowest distortion systems there in the low bass among all the overbuilt or overpriced approaches is a 24" driver shoved into a quick'n'dirty and quite flimsy sealed box thrown together out of scraps. They also don't take up more space once the displacement is factored for. A single 24" in its enclosure takes up less space than the three or four 18" drivers and their enclosures that would be required to match it in displacement (more considering that, outside of a few excellent examples, the smaller drivers will likely come up against the limits of their suspension linearity). Funny how the larger driver takes up less space, but that's how it works out in real world comparisons. More so once you factor for the cubed relationship volume has to the linear dimensions of the enclosure, so one big box can take up less floor space than multiple small boxes to get the same capability.
The 24"s also get up there in linearity for some models. I've a couple with split gap motors that are linear out to 48mm Xmax (one way, not peak-to-peak) and the cones are stiff enough I have played with them up to ~500Hz just for fun (cone scream didn't start until past that a bit).
Right now, the two options for getting high quality bass are to go big or to go some manner of complex horn loading. A 12" driver in a dorm fridge sized box just doesn't cut it these days. The physics of sound reproduction just don't allow that to have the output down low and do it cleanly. Not if there isn't the very advantageous cabin gain in a car to help it.
These days, bigger drivers can be sourced that outperform smaller drivers. The 24" drivers mentioned tend to have lower distortion at the same output levels than most 18" drivers as can be seen in the results measured and published on Data-bass.com. One of the lowest distortion systems there in the low bass among all the overbuilt or overpriced approaches is a 24" driver shoved into a quick'n'dirty and quite flimsy sealed box thrown together out of scraps. They also don't take up more space once the displacement is factored for. A single 24" in its enclosure takes up less space than the three or four 18" drivers and their enclosures that would be required to match it in displacement (more considering that, outside of a few excellent examples, the smaller drivers will likely come up against the limits of their suspension linearity). Funny how the larger driver takes up less space, but that's how it works out in real world comparisons. More so once you factor for the cubed relationship volume has to the linear dimensions of the enclosure, so one big box can take up less floor space than multiple small boxes to get the same capability.
The 24"s also get up there in linearity for some models. I've a couple with split gap motors that are linear out to 48mm Xmax (one way, not peak-to-peak) and the cones are stiff enough I have played with them up to ~500Hz just for fun (cone scream didn't start until past that a bit).
Right now, the two options for getting high quality bass are to go big or to go some manner of complex horn loading. A 12" driver in a dorm fridge sized box just doesn't cut it these days. The physics of sound reproduction just don't allow that to have the output down low and do it cleanly. Not if there isn't the very advantageous cabin gain in a car to help it.
A couple of outfits have had 80" drivers (A&D Audio and Alex Audio) for several years now, but that larger motor is interesting. The others only had ~13.5" VC, iirc. Wonder if this is just another brag product to have in the catalog like their 50" show queen that gets dragged around to look at, but never be heard, or something they actually have real world plans to sell?
So its you making that dredful noise at the end of the street...
🙂
🙂
You've made this claim earlier in the thread. Perhaps you missed my response:
What, exactly, do you mean by "support the low frequencies"?
Can you cite any evidence at all for your claims?
Chris
Chris, read any factual technical documentation please. It is not my job to prove what is industry fact, it is your job to seek out the documentation and educate yourself.
What I have said is accurate and technically correct, also borne out in practice over decades of experience. I certainly do not have the time to prove to each individual person what I learned the hard way. This would keep me too busy to practice my profession, and I am a working technician and designer. This information is available and repeated in many publications from the mid century and on up to present day. May I suggest David Weems as an author to start with?
What I have said is accurate and technically correct, also borne out in practice over decades of experience. I certainly do not have the time to prove to each individual person what I learned the hard way. This would keep me too busy to practice my profession, and I am a working technician and designer. This information is available and repeated in many publications from the mid century and on up to present day. May I suggest David Weems as an author to start with?
That is a bizarre claim to make yet audiophiles and even some big names in the review industry continue to make it. I guess headphones aren't supposed to work and in-ears can only reproduce frequencies above 3kHz because the ear canal isn't large enough to support the larger wavelengths?
Sound continues to exist below the Schroeder frequency. That room gain actually helps boost the output down there is established fact in the industry and the science of sound reproduction. There are whole chapters on it in various acoustics books, so plenty of material out there to read on it.
Sound continues to exist below the Schroeder frequency. That room gain actually helps boost the output down there is established fact in the industry and the science of sound reproduction. There are whole chapters on it in various acoustics books, so plenty of material out there to read on it.
Seriously, I don't care what papers you've read or what research you've done. If all you can do is quote your source then there's no thinking going on and no experience to relay.
For the record I'm with Chris661 on the transfer and pressure wave issues. Whatever you've been led to believe about wavelengths you'll get more perceived bass out of driver in a car (excuse the pun) than you will in a football stadium.
I happen to listen to music and my DJ experience has allowed me know certain tracks exceptionally well. On R Kelly's "Sex me Pt 2" there's a bass note on the 4th note of every other bar. I once owned a 6.5" (very cheap) bass / mid driver which claimed the note didn't exist - it refused to play it and the cone remained still. However, the 3" Sony driver makes its best attempt to reproduce a note clearly above its pay grade.
My preferred genres focus on bass and percussion. "Some Justice" by "Urban Shakedown" had a reputation as a sub-smoker. I've heard this track on 20k sound systems with 24" bass drivers - when I listen to it at home I know what's missing.
When it comes to movies my standard test is the opening 45 seconds of "The Edge of Tomorrow".
Anatech, being a spreadsheet warrior affords you no expertise. The claim that every build has performed according to expectations is am outright lie.
For the record I'm with Chris661 on the transfer and pressure wave issues. Whatever you've been led to believe about wavelengths you'll get more perceived bass out of driver in a car (excuse the pun) than you will in a football stadium.
I happen to listen to music and my DJ experience has allowed me know certain tracks exceptionally well. On R Kelly's "Sex me Pt 2" there's a bass note on the 4th note of every other bar. I once owned a 6.5" (very cheap) bass / mid driver which claimed the note didn't exist - it refused to play it and the cone remained still. However, the 3" Sony driver makes its best attempt to reproduce a note clearly above its pay grade.
My preferred genres focus on bass and percussion. "Some Justice" by "Urban Shakedown" had a reputation as a sub-smoker. I've heard this track on 20k sound systems with 24" bass drivers - when I listen to it at home I know what's missing.
When it comes to movies my standard test is the opening 45 seconds of "The Edge of Tomorrow".
Anatech, being a spreadsheet warrior affords you no expertise. The claim that every build has performed according to expectations is am outright lie.
Hi,
Headphones are an entirely different situation. You should know that.
As far as low frequency support, yes you can get low bass, but if you have ever heard low bass in a very large space you'll have to agree it is different. You can often get something done, like low bass, but getting it done properly when it agrees with physics is a different thing. It sounds much better and requires a great deal less power. The distortion is also lower and response flatter.
What I said stands. You can always hear low bass doing it incorrectly, but it will require more power and it will not be flat.
Headphones are an entirely different situation. You should know that.
As far as low frequency support, yes you can get low bass, but if you have ever heard low bass in a very large space you'll have to agree it is different. You can often get something done, like low bass, but getting it done properly when it agrees with physics is a different thing. It sounds much better and requires a great deal less power. The distortion is also lower and response flatter.
What I said stands. You can always hear low bass doing it incorrectly, but it will require more power and it will not be flat.
Anatech, your argument died when you said 'hear incorrectly'. Existence is an individual concept, Obviously your training did not extend to Descartes. In this world of audio Hearing is the only relevant benchmark. To defend your points by intimating people are not 'hearing' correctly is beyond ridiculous. Despite your claims of expertise, this layman urges you to switch to politics. I, for one, am convinced that you could cite a number of articles on the benefits of trickle-down economics. In reality it appears you are clueless.
That...makes no sense. I'm not sure you understand bass reproduction enough to make a coherent argument on the matter other than falling into claiming personal experience without measurements, a reference to a book that's severely simplified for beginners and that anyone who doesn't agree with your bizarre assertion has 'never heard it done correctly'. (I've heard that same argument before from cable peddlers and magic fuse sellers. Not good company to be keeping with.) It's a matter of the actual science behind sound reproduction and actual measurements, not subjective impressions being malformed by misinformed expectation.
In a large space, sound intensity does behave a tad differently. Sound intensity (SI), what we perceive, is a combination of particle velocity (PVL) and sound pressure (SPL). Within one wavelength, what we perceive is a combination of PVL and SPL. Mostly the latter, but more the former the closer we are. (PVL convolves into SPL with distance, it doesn't just happen all at once at a wavelength.) Beyond one wavelength distance, particle velocity will have convolved into sound pressure ensuring that sound intensity and sound pressure become one and the same. So, SPL meters more accurately reflect the sound intensity in a large space at ultra low frequencies than in a small space, but the sound itself isn't impacted by that. That doesn't mean bass cannot exist in that small space or up close. It's just slightly different in nature and requires a different means to measure (be it by crossed SPL meters and a bit of math or something like a Microflown sound intensity probe).
Below the Schroeder frequency, sound behavior actually simplifies. Above the transition frequency, you have to evaluate sound by visualize it as rays (ray acoustics) and assorted approaches. Below, you have to approach it as sound waves. Those waves don't go away, it's just you now have to deal with resonant modes and standing waves rather than reflective waves. When dealing with a pressure source (monopole speaker), this has a very particular effect: room gain. Rather than just reflecting, when the longest room wavelength is less than half the wavelength being reproduced (full wavelength reflected), the pressure doesn't negate itself, it builds. In an ideally stiff structure, this can be upwards of 12dB for each halving of the frequency. In real world scenarios 6-8dB is more like what you'll see in actual measurements, but that is quite significant. That can flatten the roll-off on a sealed design extending its practical response quite a ways down...or take the flat 2pi response of a bass reflex design and give it a horrendous hump, which has lent itself to ported boxes being perceived as slow and tubby. What it does mean is that the smaller the room, the lower the frequency, the less power that is required to reproduce it from a given subwoofer than in a larger room provided you're not sitting in a null area of the room's modal behavior. (This is why it's important to do the "sub crawl" to ensure the listening position does not end up in such a point.) Use this room gain to your advantage and you can get deeper extension for less power and, subsequently, lower distortion (because the subwoofer has to work less for the same output in a smaller room) if the room's modal behavior is accounted for.
Room modal behavior will make for a less flat response, but that can be significantly addressed with positioning and the careful use of bass traps. No need to knock out a wall to make the room bigger and sacrifice room gain in the process. You'll get much better results and bass "done properly" in a smaller room than forcing subs to overextend themselves in larger spaces and fail to reproduce the lower material cleanly. There's are reasons why so many pro subs stop around 30-35Hz and one of those is they can't do it justice in large spaces because of the disadvantages of reproduction without the help of room gain.
Dr. Floyd Toole's excellent work "Sound Reproduction: Loudspeakers and Rooms" has several chapters addressing addressing sound reproduction in rooms, big and small, their difference, advantages, disadvantages and how to work with them. I highly recommend growing beyond Weem's book and reading it. It should be considered mandatory reading at this point being such an excellent and accessible resource on room acoustics as it applies to the scale of our listening rooms.
The only time your argument has any relevance is with velocity sources such as dipoles. Those do not benefit from room gain and, instead, experience the inverse and suffer steeper roll-off the smaller the room. They do not, however, suddenly stop reproducing bass below that cut-off nor does it become bizarrely distorted because it's feeling claustrophobic. The loss is actually less than the room gain pressure sources enjoy because, to revisit that bit about sound intensity, the particle velocity will partially convolve into sound pressure even before it runs out of room. But then, dipoles (open baffles and planars) are very demanding of their owners to make them perform at their best whatever the room. I've a love/hate relationship with them for it.
Okay guys, that's fine.
I designed loudspeakers professionally for over a decade, designed bars and other venues. Was trained and studied at real schools. So I'm wrong. Cool.
I refuse to argue with folks who can't understand what's going on. Why not try studying the subject?
I designed loudspeakers professionally for over a decade, designed bars and other venues. Was trained and studied at real schools. So I'm wrong. Cool.
I refuse to argue with folks who can't understand what's going on. Why not try studying the subject?