Yes, same experience. Luckily my son lives there (he came for a 'quick' 1 month visit after graduating from university 5 years ago and never left, although I've moved on to Taiwan now) so we get to go back there every so often - and business for me of course.
What I would like to see would be an FFT scaled in nV/rtHz. That way its easy to compare to published regulator specs (from non-audiophile sources) and scale to different tasks and applications. I have an FFT analyzer that has the scaling automatic and it makes things easy. I had to build a preamp to test a power supply design that is very low noise. I scaled it to 60 dB of gain to make the noise readings direct in nV/rtHz.
The other issue with a battery is short term stability. A plot of voltage vs time scaled to say 1 uV and 1 second per division will show any "popcorn" noise type artifacts.
I have also read somewhere that the noise increases as the battery discharges. It would make some sense since the internal impedance rises as the battery discharges.
I find the plots your posting with the black background and black numbers on white difficult to read, but that may be me.
good idea Demian with the scaling.
• I would like to see not just direct battery, but regulator with battery post regulator supply, thats a more fair comparison IMO. at a minimum some quality capacitance local to the load.
• please make sure that if you use LiFePO4 that it isnt the type of pack that has an internal regulator/limiter, as these are often switchmode.
• please make it a decent brand battery and keep connections short, as the real issue with batteries is lead and package inductance. decoupling needs more attention with batteries too, as there is no feedback/error correction.
• a comparison between a fairly constant lowish current load such as a clock and dynamic higher current load is telling with badly thought out battery supplies as well. the noise of the chemical reaction increases markedly with some battery types with higher output.
sorry, not being demanding here, these are just suggestions. i'm sure you'll do a great job, judging by what i've seen of your former testing, but this comparison is of great interest to me and I use batteries quite a bit.
• I would like to see not just direct battery, but regulator with battery post regulator supply, thats a more fair comparison IMO. at a minimum some quality capacitance local to the load.
• please make sure that if you use LiFePO4 that it isnt the type of pack that has an internal regulator/limiter, as these are often switchmode.
• please make it a decent brand battery and keep connections short, as the real issue with batteries is lead and package inductance. decoupling needs more attention with batteries too, as there is no feedback/error correction.
• a comparison between a fairly constant lowish current load such as a clock and dynamic higher current load is telling with badly thought out battery supplies as well. the noise of the chemical reaction increases markedly with some battery types with higher output.
sorry, not being demanding here, these are just suggestions. i'm sure you'll do a great job, judging by what i've seen of your former testing, but this comparison is of great interest to me and I use batteries quite a bit.
Last edited:
yes. Like from Sacramento Calif to LA or to Las Vegas in one day. Sacramento to Seattle in one day + one speeding ticket. Sacramento to beyond Boise, Idaho in one day - ditto return. Or, last trip was to Arizona and got 2 speeding tickets thru Nevada ! [now that is hard to do]. A lot of wide open spaces with no ac hook up for battery cars.
I like the Orient (quaint term) so I am buying a condo there. centrally located to all that is growing and vibrant. The way we used to be. Then the severe hassels of air flight will be reduced thru check in and all -- no luggage to deal with... all left at the condo. The other airlines/countries dont subject people to the craziness that our country does. Someone in our government must think we are really, really hated by a lot of people. [we are. Didn't used to be that way].
Thx-RNMarsh
Last edited:
if you had a hefty onboard PA, perhaps you could use some sort of DSP convolution that uses a pre-recorded engine note sample vs frequency/RPM, add some sort of feedback from the throttle so the DSP knows/predicts what the engine should be sounding like at that RPM/throttle position and apply convolution 'preverb' to cancel the engine note.
pretty sure some of the stealth type helis use that sort of system dont they?
Last edited:
OK sounds like you do indeed need to wait till more range is added, it will come. of course thats if you would ever truly consider such a thing being the petrol head you clearly are
Do you think you would really ever use such a thing if the tech provides equal or better performance and economy? or you are too into the sound? which I understand btw
I had wanted to stay out of the car off topic stuff, but having a million road miles under my belt....
I did a project in Bakersfield CA. After a nonstop to LA I could either fly or drive the last leg. Using a rental car I noticed the lack of power in California legal versions. No matter how fast I drove the police officers doing speed limit enforcement always left me alone!
They were quite noticeable as they were in marked sports cars capable of doing better than 120 mph. Apparently they needed that to catch the folks who exceeded the defacto speed limit. Dejure had nothing to do with it.
The other issue was climbing the hills at speed would overheat some cars and blow the radiator hoses.
Now here in the east (but not east coast) any attempt at those speeds would not just get you a ticket, but a visit to the iron bar motel. Around here cities are located two weeks walking distance apart. If closer then it is a smaller city. A good walk is 10 to 15 miles a day. So today you can drive that in three hours or less at legal speeds.
I did a project in Bakersfield CA. After a nonstop to LA I could either fly or drive the last leg. Using a rental car I noticed the lack of power in California legal versions. No matter how fast I drove the police officers doing speed limit enforcement always left me alone!
They were quite noticeable as they were in marked sports cars capable of doing better than 120 mph. Apparently they needed that to catch the folks who exceeded the defacto speed limit. Dejure had nothing to do with it.
The other issue was climbing the hills at speed would overheat some cars and blow the radiator hoses.
Now here in the east (but not east coast) any attempt at those speeds would not just get you a ticket, but a visit to the iron bar motel. Around here cities are located two weeks walking distance apart. If closer then it is a smaller city. A good walk is 10 to 15 miles a day. So today you can drive that in three hours or less at legal speeds.
Last edited:
What the BMW Veep talked about was a car, very quiet at the outside due to regulations/laws, but on the inside, when you put down your foot, you get the characteristic roar. You drive easy, the car 'sounds' easy. It's a complete new concept and worth to think about it. Technically it is trivially easy - some DSP power with inputs from the motor management system and outputs spliced into your sound system.
Think about why we all associate power with a throaty roar: because in our experience, the two go together. What those planners are doing is making use of this coupling to give you half of it, and rely on your pavlovian reaction to fill in the other half yourself. For me it is another step in exploiting the knowledge base of the soft sciences for business purposes.
Another earlier example is Harley Davidson - they actually patented their characteristic sound, which has a close coupling in peoples' minds with the brand. Of course that sound on itself has no intrinsic value and is totally decoupled from the engine performance - it´s just another brand attribute.
Edit: qusp - missed your post, but difference is that the original motor noise is heavily attenuated and only re-generated inside the passenger cabin. No noise cancellation.
jan
Last edited:
If you want powerful but quiet, then the first muffler box after the engine needs to have more than 10x the cylinder displacement, it will kill the noise but still allow the power through.
Wrinkle
"What-a-boat!" gasped the man from the past. "Boat? No, that's my car." Barlow surveyed it with awe. Swept-back lines, deep-drawn compound curves, kilograms of chrome. He ran his hands over the door- or was it the door?-in a futile search for a handle, and asked respectfully, "How fast does it go?" The psychist gave him a keen look and said slowly, "Two hundred and fifty. You can tell by the speedometer." "Wow! My old Chevvy could hit a hundred on a straightaway, but you're out of my class, mister!"......
He was shut up as the car pulled out from the bay into the road with a great voo-ooo-ooom! A gale roared past Barlow's head, though the windows seemed to be closed; the impression of speed was terrific. He located the speedometer on the dashboard and saw it climb past 90, 100, 150, 200. "Fast enough for me," yelled the psychist, noting that Barlow's face fell in response. ".......
Other cars were showing up, all of them dreamboats. Watching them, Barlow began to wonder if he knew what a kilometer was, exactly. They seemed to be traveling so slowly, if you ignored the roaring air past your ears and didn't let the speedy lines of the dreamboats fool you. He would have sworn they were really crawling along at twenty-five, with occasional spurts up to thirty. How much was a kilometer, anyway?.....
Screamingly sweet blasts of sound surrounded them as they stopped for a red light. "What the hell is going on here?" said Barlow in a shrill, frightened voice, because the braking time was just about zero, and he wasn't hurled against the dashboard. "Who's kidding who?" "Why, what's the matter?" demanded the driver. The light changed to green and he started the pickup. Barlow stiffened as he realized that the rush of air past his ears began just a brief, unreal split second before the car was actually moving.
"The Marching Morons" written by Cyril M. Kornbluth, Galaxy Magazine April 1951 and I believe is in the public domain
Yet, all true Edo-ko go around the city by car, if they can afford it.
I did so when I lived there, or I took my motorbike, which was about twice as fast as the subway. So even in this huge metropolis with probably the best public transport system around, individual surface transport is still faster/more comfortable/ more convenient.
En route to the burning amp event, I was audited by a US border hick at the international arrivals desk in Detroit for ten minutes.
No cavity peek, not even a travel bag glance, just one meaningless question after another.
(during the friendly casual talk, I amused myself by the mental exercise of turning the all-American lard hero from grapevine to whine in 60 seconds)
The 10-minute taxi ride to the hall of fame in Dearborn, and having coffee with bridget the midget back at the airport made things right.
(Whipple supercharger. A complete LSA CTS-V crate powertrain for $17k puts any Italian to shame)
The HP line of DSA'a (Dynamic Signal Analysers) does this. Not to repeat myself several open source tools can do this easily. Python might be the easiest. It has a built-in function to compute bin width and then you only need to compute the noise BW of the windowing (only need to do this once). I'll add this to the Linear Audio article for the next issue.
What? Last time I was in Frankfurt we were escorted by Uzi armed guards out on the tarmac to re-identify our checked bags before they were loaded. There also was no discussion if they wanted to check your carry on. Same stuff in Munich, and tell me how pleasant it is connecting through Heathrow. Try entering or leaving anywhere in the Mid East with a breadboard in your carry on.
A friend just came back from a tour of Vietnam and Cambodia and reported on the spectacular emnity between some of the people in these countries. I would not relocate any closer to North Korea myself.
Last edited:
Scott,
I can assure you that I had this experience long before 9-11 here in the States. I was in Munich or Frankfurt Germany in 1985 and remember well the soldiers walking around the airport with sub-machine guns with their fingers on the trigger! This was soon after there had been some attempted bombings on the American base there. It was so different at the time than anything we had happening in any American airport, I remember it well, it was scary to see at the time.
I can assure you that I had this experience long before 9-11 here in the States. I was in Munich or Frankfurt Germany in 1985 and remember well the soldiers walking around the airport with sub-machine guns with their fingers on the trigger! This was soon after there had been some attempted bombings on the American base there. It was so different at the time than anything we had happening in any American airport, I remember it well, it was scary to see at the time.
For easy comparison something along the lines as in this nist publication would also be helpful:
http://tf.nist.gov/general/pdf/1133.pdf
Military police, and Heckler & Koch.
(Uzi is for folks who can't shoot straight anyway)
http://www.jouwfm.nl/thumbs.php?src...-Schiphol-Marechaussee-3.jpg&h=300&w=700&zc=1
You should have experienced the Spanish guardia civil in the Franco days.
- Status
- Not open for further replies.