Chris Cross ❌

as soon as he becomes more..... _comfortable_ in front of a camera.

It's straight math: a 12" has slightly bigger (i.e.: ~10%) cone area than 2 x 8" dittos. r² x pi.

@@mikaelmllersnnichsen539 Your math is correct . A typical 8 inch driver has about 210 cm^2 of surface area . A typical 12 inch has about 500 cm^2 surface area . So two 8 inches will have about 16% lower surface area than one 12 inch , and on top of that also lower max excursion (on average).

No, but approx 13inches more on a 12inch driver than two 8.

also a 12 will usually have a higher linear travel than a 8, unless it's a very beefy 8''.

Paul didn't have his calculator on him to do PI()* R^2.

There are, of course, other qualitative issues to consider.

@@howardskillington4445 The quality of low bass is almost always better and has lower distortion with larger cones. Check distortion measurements at data-bass.com.

@@gregworrel2623 Absolutely! Like we say in the engine rebuild community, there's no substitute for displacement! Back to speakers, A well engineered smaller woofer may approach the output & quality of a less engineered larger woofer, but it would also end up costing the same or even more! I'd rather have the larger, low-tech woofer for simplicity & serviceability. High tech speakers can be a nightmare to modify or repair when they stop working. A simple, robust piece of equipment can be repaired beyond the life of its owner!

What? Only one??? 😀

@@larryeckerdt9750 😂😂😂😂

It is all about price/performance/size. You could use a whole bunch of 10 inch woofers to the same effect the only problem is you would need a bunch more of them. This would likely cost more and would likely be much larger. For instance Phil Jones uses 16x5'' drivers in one of is bass cabs and it goes down 20hz. In the end there is more than one way to skin a cat. pjbworld.com/cms/index.php/products-cabinets/

2 of them in Martin Audio MLX subwoofer enclosure like design for maximum SPL.

I have 18s, they aren't slow. They don't have to travel as far for the same volume.

@@Steven--- you’re ignoring the point that there is far more mass to move and they move to an excursion decided by the physical design of the motor assembly. It’s physics. They travel to th limit identified in the electrical signal fed to them. A poorly designed 12 can be slower than an excellently designed 18 but apples to apples the 10 or 12 will be quicker and more responsive.

@@rapfreak7797 My 18" can play clearly till 100hz so unless you want to go above that then its not slow. Although I think its not necessarily a slowness that linits it higher but driver membrane resonance. If you would dampen the driver membrane you should be able to go higher.

"I know I’m not the only smartass who watches these" There's two of us but I was tangled up in the metric system

Yes, there is... *Power adders.*

gold comment. thanks Jane for neatly explaining loads of info!

Also, some in the comments thread are comparing woofers by nominal sizes, and it should be mentioned that the nominal sizes of woofers can be misleading as a representation of the effective pistonic diaphragm diameter. The Thiel-Small parameter "Sd" is the associated area (usually stated in square centimeters), and that can be converted to a diameter, which is usually much smaller than the nominal diameter. Consider that the OD of a conventional woofer surround is attached to the frame and does not move as the woofer excurses, while the ID is attached to the woofer cone and moves with the cone as the woofer excurses. The venerable Peerless 12 inch XLS model 830500 (now out of regular production, but still available to OEMs by special order in large quantities) provides a good example. The outside diameter of the frame's conventional circular mounting flange is 308_mm (12.13_in), and the effective pistonic diaphragm diameter is 244_mm (9.61_in). Xmax is 12.5_mm peak, 25_mm peak-peak. The Peerless 8 inch XLS model 850491 (likewise now out of regular production) has a truncated frame, the outside diameter of the circular portions of the mounting flange is 225_mm (8.86_in), and is 205_mm (8.07_in) across the flats of the truncated portion of the mounting flange. The effective pistonic diaphragm diameter is 173_mm (6.81_in), and Xmax is 10_mm peak, 20_mm peak-peak. Relative to the 8 inch XLS, the 12 inch XLS has 25% longer stroke and 41% larger effective pistonic diaphragm diameter, and 99% larger radiating area. Diameter comparison: 244/173= 1.41 which is a 41% increase. Area comparison: 1.41^2=1.9881 which is a 99% increase. (You can calculate the ratio of the areas long hand to find the same result as the square of the ratio of the diameters.)

@@janetyer7147 Have you written books on this stuff?!! You explained stuff so well... I always wondered about what you said... intuitively the cone indeed can move more to and fro in the center than at the edges joined to the surrounds which in turn is glued to a fixed rim... thanks once again for wonderful explanation.

The Kef KF92 is better...(£2,000)

All other things (excursion, power handling and so on) being equal, yes.

Interestingly, bass players often are not as concerned with making the 42 Hz fundamental (of a common 4-string bass) loud as they are concerned with midrange articulation. Hence the smaller drivers.

No, you are not anywhere near correct in your numbers. The nominal size of a woofer can be misleading as a representation of the effective pistonic diaphragm diameter. The Thiel-Small parameter "Sd" is the associated area (usually stated in square centimeters), and that can be converted to a diameter, which is usually much smaller than the nominal diameter. Consider that the OD of a conventional woofer surround is attached to the frame and does not move as the woofer excurses, while the ID is attached to the woofer cone and moves with the cone as the woofer excurses. The venerable Peerless 12 inch XLS model 830500 (now out of regular production, but still available to OEMs by special order in large quantities) provides good example. The outside diameter of the frame's conventional circular mounting flange is 308_mm (12.13_in), and the effective pistonic diaphragm diameter is 244_mm (9.61_in). Xmax is 12.5_mm peak, 25_mm peak-peak. The Peerless 8 inch XLS model 850491 (likewise now out of regular production) has a truncated frame, the outside diameter of the circular portions of the mounting flange is 225_mm (8.86_in), and is 205_mm (8.07_in) across the flats of the truncated portion of the mounting flange. The effective pistonic diaphragm diameter is 173_mm (6.81_in), and Xmax is 10_mm peak, 20_mm peak-peak. Relative to the 8 inch XLS, the 12 inch XLS has 25% longer stroke and 41% larger effective pistonic diaphragm diameter, and 99% larger radiating area, which is very nearly double, and is very much more than the 13% increase that you stated. Diameter: 244/173= 1.41 which is 41% increase. Area: 1.41^2=1.9881 which is 99% increase (You can calculate the ratio of the areas long hand to find the same result as the square of the ratio of the diameters.)

Hopefully this long project duration means they are doing amazing stuff. I like to see an outstanding SPL, transient and low distortion response in the bass through servo feedback. They should also include active phase optimized cross-over filtering. If PS Audio can do great amps and speakers...they seriously need to combine the skills to the next level. What we don't need is just another 1980s engineering-level sort of old-school passive speaker that won't beat what we've seen before.

Well, pushing an 8” driver to the bloody edge is going to sound worse than a 12” driver on cruise

That shouldnt be hard for me either i hit a 156.8 at 30hz

Don't hold your breath...

@@stonefree1911 Well I know they were working on them. Paul even showed us some prototypes in past videos. I just want to know when they're coming out, even if it won't be in the near future.

A bit more accurate is the simple mental arithmetic. An 8 area is 4X4X3 =48. A 12 area is 6X6X3=108.

@@geoff37s38 comes out the same with less work. The 3 is redundant and doesn't change the outcome, so skip it and save the time.

@@The340king your method is for a square, not a circle so it does not work out the same.

@@geoff37s38 yes it does. The only unique factor in the equation for the area of a circle is? The diameter/radius. All the rest is constants. Therefore, solving for the difference in diameter squared gives you a quick method for comparing cross sectional area of a circle.

😂larger the worse she moan.

Music for butterflies.

How does the posi trac on a '72 Plymouth work? Nobody knows, it just does!

2 8" drivers don't produce lower frequencies, and the single 12" driver doesn't produce lower frequencies either. Lower frequency simply put means the driver moves slower over a given time period. What Paul was talking about and again his cocktail napkin math is way off is the ability to "couple" with the air or put another way to get air moving at the same frequency aka speed as the driver. Air is a group of molecules of a certain density in space, the air molecules having a physical mass and size. One of the physical laws of the universe simply state that things at rest tend to stay at rest. Air has a resistance to changing it's at rest state to being moved. A woofer's surface traps some air and shoves it forward and back causing a wave in the space it sits in. This wave moves in the room in a more spherical shape the lower the frequency gets and more like a narrowing conical shape the higher the frequency gets. The narrowing effect is due to the air requiring more energy to move faster, aka at a higher frequency, so any angle off axis to the driver's forward and back movement gets absorbed more the higher the frequency goes. And to drive a speaker surface at higher frequency using the same energy levels requires the size of the speaker to get smaller because that air resistance is there. That's why tweeters are smaller than midranges and woofers are bigger. How they move the air most efficiently depends on the frequency they are trying to move the air. A small tweeter can reproduce frequencies down to 20 Hz and lower, it just requires more surface area to get it moving with any volume level. Conversely a woofer can reproduce 20Khz signals, but would require more wattage to drive at that frequency and need to be made to a more rigid and stronger level to survive for long because of that air resistance being worse the higher the frequency. So to sum up, better coupling to the air at lower frequencies means you can drive the air mass at higher volume levels at those harder to drive lower frequencies. Being able to reproduce higher volume levels mean you get to actually hear those frequencies at the listening level of the rest of the frequencies being reproduced. So the more air you can couple to, the more you can balance the lower frequencies' volume to the rest of the higher frequency material being reproduced. There are other issues other than just size, you need to support that larger moving mass against being deflected off axis by the air's resistance to moving. The more you try to move air, the more you need to counteract deflection from air resistance. AKA larger stiffer spider, larger voice coil and larger magnet, stiffer cone, more accurately sized surround and mated to the cone more accurately as well, more perfectly centered cone and more equidistant from the coil it needs to be. It's cheaper and easier to a speaker manufacturer who also manufactures their own drivers to use smaller drivers in groupings to get more air moving at low frequencies. Also smaller drivers allow narrower cabinets which means wider acceptance with general market trends for "attractive" designs.

@@robertspringer9477 The same as '72 Dodge.

Seek help.😊

I've run into the opposite. Have 6.5 in bookshelves that produces more bass, tighter base, than towers with three 5-in drivers. I'll take one legit driver over cheap multiples any day.

Maybe it’s Italian?

@@PooNinja Are you thinking Faital? I know ive seen that magnet design somewhere come to think of it.

Psssssst...

Only his hairdresser knows..............................

So many things not entirely accurate with those 2 simple statements. All air movement results in sound, vibration is movement, and sound is caused by the ear drum being vibrated/excited usually by air movement but you could be underwater or drowning in an oil drum for that matter and hear things.

@oh ok explain how frequency transmission is possible through space. There’s no air.

He trips up over his own words quite often. It's "mass". Pertaining to what? Moving mass of driver? Cone? No, it isn't. It's displacement of air volume, which can affect air mass movement. Cone surface area and travel (excursion) have no direct relation to cone mass. True, larger cones tend to require more massive material, but there is no direct relation, as larger, more efficient drivers generally use materials of lower density and higher quality than smaller, cheaper, less efficient woofer drivers. I do get a kick out of these video clips, though. One intriguing aspect of following these videos is finding the errors.