All I can say is you know nothing about how loud steel wheels on steel rails are.
I've consulted on rail transit & freight rail noise issues in 26 states, one U.S. territory, and 2 countries. My analyses have withstood scrutiny by college professors (including one nobel prize winner), other consultants, and many lawsuits. I've contributed to national rail noise standards and I've trained state officials in transit noise control on behalf of FTA. I've presented info on noise & vibration analysis at national conferences, and I have two transit noise-related papers that will be published in refereed acoustics journals over the next year.
In short, I know a lot about "how loud steel wheels on steel rails are."
For the 3rd time, the Chicago El is not light rail - the trains are longer, heavier, faster, and more frequent, all of which make them louder than typical light rail systems. I'm also willing to bet that the age and maintenance on the El is a significant contributer to its perceived loudness.
Since you live in Seattle, take a drive down to Portland and have a listen to the Portland Max LRT system. Hopefully you'll see what I'm talking about.
Second, I'd much rather move back under the whoosh of the monorail than the clankety-clack of the el or train tracks.
Jointed tracks cause the "clickety-clack" most people are familiar with. Modern systems use Continuously welded rail to solve this problem.
I'm not surprised at all to see light rail evangelists spreading FUD
Referring to me? I'm for transit in all its forms (bus/BRT, LRT, heavy rail, monorail, even maglev)but I just want to make sure people make their decisions for the right reasons.
Not saying wheels don't make noise, but AFAIK most highway noise comes from cars' engines, not the wheels.
For autos above 30 mph on level roads, wheel/road noise dominates. For medium and heavy trucks, it tends to be an almost even mix of exhaust/stack noise and wheel/road noise. For trucks going uphill, (I think) engine noise dominates.
So, does Sound Transit also pay you to spread uninformed FUD, or do you do that on your own time?
Someone didn't get their naptime today....
The monorail board released specs on the decibels created by the new monorail. Can you comment on those?
The info from the monorail FEIS site (based on measurements of the Walt Disney World monorail) indicates that the monorail (at 40 mph) is a bit quieter than "rail transit" (at 50 mph) - the specifics aren't very clear and I don't know if they're comparing apples to apples (the technical appendix doesn't seem to clear things up). On the other hand, FTA says that monorails are about the same, or a bit louder than LRT - this info is based on a survey of several systems (and peer reviewed).
Best case: it's a wash. Worse case? Well compare the existing monorail to the Portland Max and decide for yourself.
And for comparisons, I can barely stand to *be* in the underground stations in Chicago when the El comes screeching in.
The El isn't light rail - the El bears about as much relationship to modern light rail as the '64 impala does to the Prius.
Quieter -- They use non-metallic wheels, often on a non-metallic surface, though I don't know if this applies to high-speed monorails.
I worked on the noise & vibration analysis for the Sound Transit light rail EIR. One of the criticisms I heard over & over again was that the city should expand the monorail system instead of building a light rail system because the monorail would be quieter.
In the case of the existing Seattle monorail, this is completely wrong - the Seattle monorail is easily one of the (if not *the*) loudest surface-transit systems in the country. If you're a resident of the pacific northwest, all you have to do is listen to the monorail, then head down to Portland to hear their light rail system (which will be similar to the proposed Seattle system), it's no contest.
[As an aside, I can tell you about the first time I head the monorail. My boss and I were sitting in a car under the monorail guideway near the Space Needle terminus. All of a sudden, I head this huge roar, and the car started to shake. I seriously thought the rapture was upon us, until my boss said "here comes the monorail." Quiet my a$$]
In any event, rubber wheels (which is what the Seattle monorail uses) moving on a concrete or steel surface certainly makes noise - otherwise highways would be quiet. Depending on the exact configuration, it's not necessarily true that rubber wheels on concrete or steel is quieter then steel wheels on steel rails since train wheels are designed to have a very small contact patch to minimize friction, and hence, noise. And don't forget the additional radiated sound you would get from the elevated monorail guideway.
Reference please. I see many Apple shills pulling this out, but it seems to be contradicted by Xerox sueing Apple.
The very link you provided contains the following statement: "Mr. Jobs had been permitted to visit the Xerox laboratory in return for allowing Xerox to invest in one of Apple's last private financing offerings." More links.
they didn't steal Apple's copyrighted code did they?
Efficiency (especially for a sub) can be increased by several methods including:
Increasing cabinet volume (or, alternatively stuffing the cabinet with some appropriate material).
Enclosure type (obviously a ported enclosure will be more efficient than a sealed enclosure since you're using the output from both sides of the driver).
Driver spider/surround stiffness.
Efficiency of the magnetic motor (which includes the strength of the permanent magnet, diameter and length of the voice coil, tightness of the winding, size of the gap).
Mass of the diaphragm (as you pointed out).
I suppose you could say that there is an "indirect" relationship between freq response and sensitivity. However, the reality is that here are a lot of parameters that you can play around with such that it's not really a problem. For example, a small sealed enclosure might reduce efficiency, but that can be offset by choosing a driver with a low moving mass and high Bl motor.
The first thing you need to find out is the efficiency of speakers. For instance, my speakers have an efficiency of 92 dB/W, which means that at a power level of 1 W, they will produce 92 dB of sound.
Everything you wrote is true, but I have to nitpick just a little;)
The effeciency of a speakers is given in terms of output per watt at a reference distance (e.g. 92 dB 1 watt at 1 meter). It's generally understood that the sensitivity is measured at 1 meter, but if a loudspeaker specification doesn't give the distance, you might want to be a little suspicious - for example a speaker with an sensitivity of 92 dB 1 watt at 1 centimeter is going to be a lot less efficient than a speaker with an efficiency of 92 dB 1 watt at 1 meter.
Also, you may sometimes see the speaker sensitivity given as xx dB at 2.83 volts instead of 1 watt - 1 Watt is 2.83V into 8ohms, so a reference voltage of 2.83V is used for non-8ohm speakers.
One last point for people who buy separate amps and loudspeakers: you're more likely to damage your speakers by using a amp that outputs too little power than too much power. Most speakers can handle a lot of juice for short periods, given enough cool-down time. However, a low-power amp played loudly can cause clipping, and clipping will fry your tweeters pretty quickly.
Also note, that the flatter and wider the responce curve is, the lower the efficiency rating is going to be.
That's not true - the frequency of a speaker and its efficiency are not related at all. (exhibit 1: the Wilson Watt Puppy has a sensitivity of 93 dB 1 W/m)
That's not to say that you might not see a speaker with a flat-response and low efficiency, but it's not a causal relationship.
Seriously, has anyone ever read anything by Mossberg about Apple products that wasn't either glowing, stellar, or outright raving?
Yup. For example, there was his infamous WSJ article in 1997 that rejected Apple's Rhapsody strategy and advocated that people dump Macs and move to Windows. I can't find the article online, but you can see responses to the article here and here.
I agree with the other posters - I remember Mossberg being pretty anti-Mac (or at least not pro-Mac) until around the time the first iMac was released.
Well, presumably if you're taking "that short drive to the grocery store" you going to have your wallet, your purse, and/or your keychain with you.;)
Point taken, but I like I said, it's about the trade-off between convenience and privacy. With an external carrier, you're at least in control.
In the recent I've prescribed medication that was potentially dangerous because of interference with another drug that the patient was taking but forgot to tell me about when asked
Instead of storing this data in an implanted chip, why not encode this data on re-writable magnetic strip on a credit-card-type card (with no personally identifiable info) that you can keep in your wallet/purse/keychain etc?
It's a good idea to have this info available for legitimate medical uses, but an implanted RFID doesn't do enough to strike a balance between privacy and usefulness.
Teamwork = "gang mentality"? I assume you don't work in the real world...
2. Simulation of hand to hand combat
Football taught me very little that would be useful in hand-to-hand combat. I would argue just the opposite, since most of the actions you could do to really hurt someone is illegal in football (and believe it or not, being tackled doesn't hurt all that much most of the time).
3. Physical prowess is more important than intellectual activities because parents and fans do not drive even 1 mile for chess club tournaments.
Nope. Ever seen a football playbook? If you're not smart, you can't take care of your individual responsibility, and your team loses. The intellectual prowess is just as important as physical prowess if you want to win at football. Just ask Bill Belichick
4. Brutalizing another into submission by tackling.
"Brutalizing"? Sometimes perhaps. But if tackling was truly brutal all the time, people wouldn't play the game. If you know how to tackle, and how to be tackled, it's not that bad.
5. Your knees and back when young can be abused but as you get older the pain intensifies long after you would of stopped had you known.
Yep. But the same can be said for other physical activities, like working construction or other heavy lifting. We all need to learn to care for our bodies, which, (not coincidentally) is a large focus of football training.
It sounds like you've have bad experiences with football players. If that's true, that's too bad, but with the proper guidance, football teaches you the value of teamwork, strategy and physical fitness. You could certainly do worse.
Proper digital is vastly superior to analog. in analog you CANNOT get a 0 db noise floor....
First of all, I agree that a properly-engineered digital audio signal will be superior to a properly-engineered analog audio signal. That said, what you wrote above is not correct.
A '0 db noise floor' is not meaningful - analog or digital can have a 0 dB noise floor provided you use the right reference quantity! If you mean that a digital signal has no noise, that's wrong. Because a continuous analog signal has to be mapped to a limited number of digital quantum levels, small errors are created when the signal is generated. These errors create quantization noise, which result in a slight 'metallic' or 'watery' sound. The amount of quantization noise varies based on the amplitude of the signal, but it does create a digital noise floor.
The audible effects of quantization noise can be reduced by adding dither, but this increases the overall noise floor. It's still better than analog audio, but it's not 0.
Secondly dynamic range of analog is limited. Yes, you are limited by the noise floor and limitations of the analog medium. Digital can go from 0.1db to 100db and back again faster than any analog setup.
Don't confuse the limitations of consumer analog equipment with the limitations of analog equipment. It's entirely possible to produce analog equipment with performance that rivals digital audio equipment (some professional reel-to-reel or instrumentation FM audio recorders for example). It's just not easy to do it cheaply.
The 192 KHz range allows instrument harmonics up to about 60KHz to be reproduced accurately.
But considering that most modern (non-measurement) microphones crap out at 12-20 kHz, 192kHz sampling rate might just be overkill in terms of extending the frequency response.
A high sampling rate is useful because it allows for a simpler low-pass filter instead of a brick wall filter, but don't think that you're going to start hearing data at 50 kHz, 'cause it just ain't there.
I bet you can't remember who you walked past and what they were wearing at 8:03am today, let alone something that happened a few weeks ago.
Well, since I was sleeping at 8:03am, I can tell you exactly who I walked past at that time;)
As more memories being fallible? Yeah, I agree with that - to an extent. Not remembering the oncoming car? That's a small detail. Not remembering whether or not a street is one- or two-way? That's a pretty big "small detail" - especially for (presumably) the cop's home territory and likely a location that has been patrolled before or since.
I just performed a little experiment: Three years ago, I worked for 4 months in NYC on a subway project. Over the course of that project, I performed tasks at several locations in Manhattan, which are shown as dots on a schematic map in a technical report. Just looking at dots on the map, I tried to remember whether or not the streets were one or two way. I then used Google maps and project photos of the area to see if I was right.
I scored 100%. And I haven't been to NYC in 3 years.
If a cop couldn't remember that detail, that cop needs to learn how to take notes - or that cop needs a new career.
when the officer asks do you know how fast you were going [....] However, I've wondered what the correct answer would be?
Answer: "I was moving with the flow of traffic"
If the cop's response indicates that the flow of traffic was exceeding the speed limit, you're pretty much screwed, but you can try to argue that it's safer to move at the speed of the traffic flow than to go faster or slower than the traffic (which is true BTW).
although the flaw, from what I could tell, was not directly related to whether the offense was committed or not.
I can't get to the article right now, but I also saw it yesterday. IIRC, the defendant's argument was that he was in the intersection to make a left turn, but had to wait for an oncoming car to clear the intersection before he could turn. The cop said that could not have happened because the street was one-way. Being able to demonstrate that the street was two-way was significant because it showed that his story was plausible - not to mention calling into question the arresting officer's ability to observe a crime-in-progress.
Out of curiousity what driver (brand/model) would you have chosen for such a project or what would you recomend?
Well, I haven't run the numbers for that specific enclosure, but two highly regarded subwoofers with which I have personal experience include the NHT/Tonegen 1259 (I'm not sure it's still availble) and the Adire audio Shiva.
Speaker manufacturers go through great lengths (no pun intended) to assure that the internal dimensions of the enclosure do not allow standing waves to build up. In "box" enclosures, the length, width and height are all differing dimensions, with no dimension being a multiple of the other.
The Death Star subwoofer is, well, a subwoofer. Most subwoofer crossovers filter frequencies above 80 to 100 Hz, per Dolby & THX recommendations, so the maximum frequency that will (hopefully) be generated by this sub is 100 Hz. The wavelength of 100 Hz is roughly 10 ft. The half wavelength at 100 Hz is 5 ft. The diameter of the Death Star subwoofer is 3 ft.
Basically, the smallest half-wavelength that will be generated by the subwoofer is greater than the diameter of the cabinet, so standing waves just aren't an issue here. It is something that needs to be considered for higher-frequency speakers, but a lot of the "rules-of-thumb" that are applicable to mid/high-frequency speakers don't apply to subwoofers because the wavelengths of bass frequencies are so large. (some gotcha's, like baffle-step, may apply, depending on the geometry of the cabinet)
that thing just doesn't have the sheer wattage or box design, or even a speaker worth a damn
On what, exactly, are you basing this? The enclosure is a ported 10-cubic foot enclosure - 5 times the recommend cabinent space - which is a good thing for (properly modeled and constructed) subwoofers because it increases efficiency and helps the low-frequency extension. I'm sure it's not a "one-note" bandpass monster, but then again, that's a good thing.
Wattage? Again, increasing the volume size of the cabinet results in a more efficient design which means that you (literally) get more bang per watt. Then again, if you were to double the peak power, you would only raise the peak SPL by a max of 6 dB (and probably less since thermal compression would become more of an issue with the increased power).
And the Alpine driver? I'll be the first to admit the car audio drivers tend to be overpriced and have less bass extension than comparably-sized home audio driver (car subwoofers depend on cabin gain for low-frequency response). However, the Alpine SWS-1242D is reasonably priced (available for as low as $80). Also, the large cabinet volume will help with the low-frequency response.
This probably isn't the best subwoofer on the planet, but I'd bet that it sounds reasonably good, perhaps even great. It's hard to say without looking at measurement results, or hearing it. But criticizing it without taking a closer look at the facts is a disservice to everyone.
Slashdot Mirror
I've consulted on rail transit & freight rail noise issues in 26 states, one U.S. territory, and 2 countries. My analyses have withstood scrutiny by college professors (including one nobel prize winner), other consultants, and many lawsuits. I've contributed to national rail noise standards and I've trained state officials in transit noise control on behalf of FTA. I've presented info on noise & vibration analysis at national conferences, and I have two transit noise-related papers that will be published in refereed acoustics journals over the next year.
In short, I know a lot about "how loud steel wheels on steel rails are."
For the 3rd time, the Chicago El is not light rail - the trains are longer, heavier, faster, and more frequent, all of which make them louder than typical light rail systems. I'm also willing to bet that the age and maintenance on the El is a significant contributer to its perceived loudness.
Since you live in Seattle, take a drive down to Portland and have a listen to the Portland Max LRT system. Hopefully you'll see what I'm talking about.
None of which are representative of LRT. To have a better sense of light rail, go see DART, Houston METRO, Salt Lake City UTA, St. Louis Metrolink, San Francisco MUNI, Santa Clara VTA, Philadelphia SEPTA, Portland Max, Baltimore MARC, and so on.
Second, I'd much rather move back under the whoosh of the monorail than the clankety-clack of the el or train tracks.Jointed tracks cause the "clickety-clack" most people are familiar with. Modern systems use Continuously welded rail to solve this problem.
I'm not surprised at all to see light rail evangelists spreading FUDReferring to me? I'm for transit in all its forms (bus/BRT, LRT, heavy rail, monorail, even maglev)but I just want to make sure people make their decisions for the right reasons.
For autos above 30 mph on level roads, wheel/road noise dominates. For medium and heavy trucks, it tends to be an almost even mix of exhaust/stack noise and wheel/road noise. For trucks going uphill, (I think) engine noise dominates.
More info in the Traffic Noise Model Technical Manual.
Someone didn't get their naptime today....
The monorail board released specs on the decibels created by the new monorail. Can you comment on those?The info from the monorail FEIS site (based on measurements of the Walt Disney World monorail) indicates that the monorail (at 40 mph) is a bit quieter than "rail transit" (at 50 mph) - the specifics aren't very clear and I don't know if they're comparing apples to apples (the technical appendix doesn't seem to clear things up). On the other hand, FTA says that monorails are about the same, or a bit louder than LRT - this info is based on a survey of several systems (and peer reviewed).
Best case: it's a wash. Worse case? Well compare the existing monorail to the Portland Max and decide for yourself.
And for comparisons, I can barely stand to *be* in the underground stations in Chicago when the El comes screeching in.The El isn't light rail - the El bears about as much relationship to modern light rail as the '64 impala does to the Prius.
They are.
I worked on the noise & vibration analysis for the Sound Transit light rail EIR. One of the criticisms I heard over & over again was that the city should expand the monorail system instead of building a light rail system because the monorail would be quieter.
In the case of the existing Seattle monorail, this is completely wrong - the Seattle monorail is easily one of the (if not *the*) loudest surface-transit systems in the country. If you're a resident of the pacific northwest, all you have to do is listen to the monorail, then head down to Portland to hear their light rail system (which will be similar to the proposed Seattle system), it's no contest.
[As an aside, I can tell you about the first time I head the monorail. My boss and I were sitting in a car under the monorail guideway near the Space Needle terminus. All of a sudden, I head this huge roar, and the car started to shake. I seriously thought the rapture was upon us, until my boss said "here comes the monorail." Quiet my a$$]
In any event, rubber wheels (which is what the Seattle monorail uses) moving on a concrete or steel surface certainly makes noise - otherwise highways would be quiet. Depending on the exact configuration, it's not necessarily true that rubber wheels on concrete or steel is quieter then steel wheels on steel rails since train wheels are designed to have a very small contact patch to minimize friction, and hence, noise. And don't forget the additional radiated sound you would get from the elevated monorail guideway.
The very link you provided contains the following statement: "Mr. Jobs had been permitted to visit the Xerox laboratory in return for allowing Xerox to invest in one of Apple's last private financing offerings." More links.
they didn't steal Apple's copyrighted code did they?For the GUI, no. For Quicktime (AVI), tes
Efficiency (especially for a sub) can be increased by several methods including:
I suppose you could say that there is an "indirect" relationship between freq response and sensitivity. However, the reality is that here are a lot of parameters that you can play around with such that it's not really a problem. For example, a small sealed enclosure might reduce efficiency, but that can be offset by choosing a driver with a low moving mass and high Bl motor.
Everything you wrote is true, but I have to nitpick just a little ;)
The effeciency of a speakers is given in terms of output per watt at a reference distance (e.g. 92 dB 1 watt at 1 meter). It's generally understood that the sensitivity is measured at 1 meter, but if a loudspeaker specification doesn't give the distance, you might want to be a little suspicious - for example a speaker with an sensitivity of 92 dB 1 watt at 1 centimeter is going to be a lot less efficient than a speaker with an efficiency of 92 dB 1 watt at 1 meter.
Also, you may sometimes see the speaker sensitivity given as xx dB at 2.83 volts instead of 1 watt - 1 Watt is 2.83V into 8ohms, so a reference voltage of 2.83V is used for non-8ohm speakers.
One last point for people who buy separate amps and loudspeakers: you're more likely to damage your speakers by using a amp that outputs too little power than too much power. Most speakers can handle a lot of juice for short periods, given enough cool-down time. However, a low-power amp played loudly can cause clipping, and clipping will fry your tweeters pretty quickly.
That's not true - the frequency of a speaker and its efficiency are not related at all. (exhibit 1: the Wilson Watt Puppy has a sensitivity of 93 dB 1 W/m)
That's not to say that you might not see a speaker with a flat-response and low efficiency, but it's not a causal relationship.
Yup. For example, there was his infamous WSJ article in 1997 that rejected Apple's Rhapsody strategy and advocated that people dump Macs and move to Windows. I can't find the article online, but you can see responses to the article here and here.
I agree with the other posters - I remember Mossberg being pretty anti-Mac (or at least not pro-Mac) until around the time the first iMac was released.
...brings back some memories...
Well, presumably if you're taking "that short drive to the grocery store" you going to have your wallet, your purse, and/or your keychain with you. ;)
Point taken, but I like I said, it's about the trade-off between convenience and privacy. With an external carrier, you're at least in control.
Instead of storing this data in an implanted chip, why not encode this data on re-writable magnetic strip on a credit-card-type card (with no personally identifiable info) that you can keep in your wallet/purse/keychain etc?
It's a good idea to have this info available for legitimate medical uses, but an implanted RFID doesn't do enough to strike a balance between privacy and usefulness.
Teamwork = "gang mentality"? I assume you don't work in the real world...
2. Simulation of hand to hand combatFootball taught me very little that would be useful in hand-to-hand combat. I would argue just the opposite, since most of the actions you could do to really hurt someone is illegal in football (and believe it or not, being tackled doesn't hurt all that much most of the time).
3. Physical prowess is more important than intellectual activities because parents and fans do not drive even 1 mile for chess club tournaments.Nope. Ever seen a football playbook? If you're not smart, you can't take care of your individual responsibility, and your team loses. The intellectual prowess is just as important as physical prowess if you want to win at football. Just ask Bill Belichick
4. Brutalizing another into submission by tackling."Brutalizing"? Sometimes perhaps. But if tackling was truly brutal all the time, people wouldn't play the game. If you know how to tackle, and how to be tackled, it's not that bad.
5. Your knees and back when young can be abused but as you get older the pain intensifies long after you would of stopped had you known.Yep. But the same can be said for other physical activities, like working construction or other heavy lifting. We all need to learn to care for our bodies, which, (not coincidentally) is a large focus of football training.
It sounds like you've have bad experiences with football players. If that's true, that's too bad, but with the proper guidance, football teaches you the value of teamwork, strategy and physical fitness. You could certainly do worse.
First of all, I agree that a properly-engineered digital audio signal will be superior to a properly-engineered analog audio signal. That said, what you wrote above is not correct.
A '0 db noise floor' is not meaningful - analog or digital can have a 0 dB noise floor provided you use the right reference quantity! If you mean that a digital signal has no noise, that's wrong. Because a continuous analog signal has to be mapped to a limited number of digital quantum levels, small errors are created when the signal is generated. These errors create quantization noise, which result in a slight 'metallic' or 'watery' sound. The amount of quantization noise varies based on the amplitude of the signal, but it does create a digital noise floor.
The audible effects of quantization noise can be reduced by adding dither, but this increases the overall noise floor. It's still better than analog audio, but it's not 0.
Secondly dynamic range of analog is limited. Yes, you are limited by the noise floor and limitations of the analog medium. Digital can go from 0.1db to 100db and back again faster than any analog setup.Don't confuse the limitations of consumer analog equipment with the limitations of analog equipment. It's entirely possible to produce analog equipment with performance that rivals digital audio equipment (some professional reel-to-reel or instrumentation FM audio recorders for example). It's just not easy to do it cheaply.
But considering that most modern (non-measurement) microphones crap out at 12-20 kHz, 192kHz sampling rate might just be overkill in terms of extending the frequency response.
A high sampling rate is useful because it allows for a simpler low-pass filter instead of a brick wall filter, but don't think that you're going to start hearing data at 50 kHz, 'cause it just ain't there.
Well, since I was sleeping at 8:03am, I can tell you exactly who I walked past at that time ;)
As more memories being fallible? Yeah, I agree with that - to an extent. Not remembering the oncoming car? That's a small detail. Not remembering whether or not a street is one- or two-way? That's a pretty big "small detail" - especially for (presumably) the cop's home territory and likely a location that has been patrolled before or since.
I just performed a little experiment: Three years ago, I worked for 4 months in NYC on a subway project. Over the course of that project, I performed tasks at several locations in Manhattan, which are shown as dots on a schematic map in a technical report. Just looking at dots on the map, I tried to remember whether or not the streets were one or two way. I then used Google maps and project photos of the area to see if I was right.
I scored 100%. And I haven't been to NYC in 3 years.
If a cop couldn't remember that detail, that cop needs to learn how to take notes - or that cop needs a new career.
Answer: "I was moving with the flow of traffic"
If the cop's response indicates that the flow of traffic was exceeding the speed limit, you're pretty much screwed, but you can try to argue that it's safer to move at the speed of the traffic flow than to go faster or slower than the traffic (which is true BTW).
I can't get to the article right now, but I also saw it yesterday. IIRC, the defendant's argument was that he was in the intersection to make a left turn, but had to wait for an oncoming car to clear the intersection before he could turn. The cop said that could not have happened because the street was one-way. Being able to demonstrate that the street was two-way was significant because it showed that his story was plausible - not to mention calling into question the arresting officer's ability to observe a crime-in-progress.
Well, I haven't run the numbers for that specific enclosure, but two highly regarded subwoofers with which I have personal experience include the NHT/Tonegen 1259 (I'm not sure it's still availble) and the Adire audio Shiva.
There are lots of other recommended models at the Loudspeaker Designer's Selection Guide.
The Death Star subwoofer is, well, a subwoofer. Most subwoofer crossovers filter frequencies above 80 to 100 Hz, per Dolby & THX recommendations, so the maximum frequency that will (hopefully) be generated by this sub is 100 Hz. The wavelength of 100 Hz is roughly 10 ft. The half wavelength at 100 Hz is 5 ft. The diameter of the Death Star subwoofer is 3 ft.
Basically, the smallest half-wavelength that will be generated by the subwoofer is greater than the diameter of the cabinet, so standing waves just aren't an issue here. It is something that needs to be considered for higher-frequency speakers, but a lot of the "rules-of-thumb" that are applicable to mid/high-frequency speakers don't apply to subwoofers because the wavelengths of bass frequencies are so large. (some gotcha's, like baffle-step, may apply, depending on the geometry of the cabinet)
On what, exactly, are you basing this? The enclosure is a ported 10-cubic foot enclosure - 5 times the recommend cabinent space - which is a good thing for (properly modeled and constructed) subwoofers because it increases efficiency and helps the low-frequency extension. I'm sure it's not a "one-note" bandpass monster, but then again, that's a good thing.
Wattage? Again, increasing the volume size of the cabinet results in a more efficient design which means that you (literally) get more bang per watt. Then again, if you were to double the peak power, you would only raise the peak SPL by a max of 6 dB (and probably less since thermal compression would become more of an issue with the increased power).
And the Alpine driver? I'll be the first to admit the car audio drivers tend to be overpriced and have less bass extension than comparably-sized home audio driver (car subwoofers depend on cabin gain for low-frequency response). However, the Alpine SWS-1242D is reasonably priced (available for as low as $80). Also, the large cabinet volume will help with the low-frequency response.
This probably isn't the best subwoofer on the planet, but I'd bet that it sounds reasonably good, perhaps even great. It's hard to say without looking at measurement results, or hearing it. But criticizing it without taking a closer look at the facts is a disservice to everyone.
I see your folded horn and raise you one flatbed-mounted horn...
There are at least some out there that would say the article is heavily biased. Not that these responses aren't.
Me? I like RSS 2.0. It's simple (for what is does), and extensible (for most of what it doesn't). To each their own.