Funny how nobody complains about missing distortion profiles of speakers.
But people instead are worried about 0,00001% THD of amp
Good point !
The precedent for this dates back to the days when speaker measurements had rather limited meaning, if you catch my drift. Also, as questionable as the measurements were, it took an arm and a leg to buy the equipment that was required to do it.
But people instead are worried about 0,00001% THD of amp
Some people may, but not others.
I think its more about wanting to get others worried about that infinite row of leading zeroes, for fun and profit.
Also, if you want to avoid that really complex and difficult area of technology called rooms and speakers, then sticking with electronics makes sense.
Speakers (mechanical devices) have a benefit of less higher harmonics. Simply because its harder to move physical things faster than the excitation. Higher harmonics from a speaker indicate rubbing or similar real problems. Electronics tend to have ways to generate higher harmonics (crossover, distinct nonlinear loads etc.) and being massless no easy way to suppress them. I would suspect harmonics below some level (-80 dB?) would be completely inaudible no matter the source but other disagree. I feel that fixing known problems (frequency response, distortion, noise) should be done as well as the technology will support since it really is not a cost adder.
Speakers is where we switch off and many problems they have were the same in the 1950's. I note that the KEF LS50 has 0.8% THD. They are rightly proud. It should be 0.1% by now. I am not sure how quiet they need to be to do that?
Jan. As promised the FET question was raised at the pub. Johns point of view is that is matters in the same way as cars must do 155MPH ( even diesel these days ). It's the box that must be ticked. John said in the PA world FET's devellope hot spots and die without warning. For the pennies it costs they fit multiple devices for that reason more than others. John agreed with you that domestic amplifiers shouldn't need it. In non class D PA has reverted to bipolar.
Another point he made was that trying to make the output stage bomb proof seems to cause driver failiure. I asked why not use a high gain T03P/247 like C5200/A1943 as drivers? He didn't think they would have the gain. As a group in and out they could. Johns last project of this type was a Helmholtz coil and amplifer which is a few R load with massive inductance. I gave him Douglas Selfs book of recipes which he found very useful to simplify the design. Self refines the function of an amplifier down to the dominant single pole ( in principle ). Even so the amplifier took months of work. The back EMF being the problem. Simulation using SIMetrix found nearly all of the nasties. It didn't ice the cake and get reliability. John walked out of that company when the bean counters came in. The project 95% wrapped up. The test set costs $30000 +. He says they are nowhere near reliable yet. He did it to prove a point. The boss is not an engineer, although may have a degree in similar. The best way to prove it is to walk out. It's a pyrrhic victory. The boss even tried to win arguements about electronics. That would be like taking Einstein on, John is that gifted. Last he heard the amplifier had been completely redesigned and now is worse. Mostly the coil was the next design problem as the devices in the amplifier are best of type.
We did discussed if a bipolar collector resistor of 1R and 0R22 at the emitter could be useful rather than the conventional current limiter. The jury is out on that one. It won't work exactly work like a FET. It might be better than the usual.
Jan your best point although I don't think you meant it is where is the Ron ( Rds on ) ? We can't say it's in the almost a collector . Nor can we say it's in the source like an external re . Actually it isn't very important. Looking at a bipolar device is looks very interesting to add 1R to the collector. If the analogy with a FET holds up it should work very well. Never seen it in a book. If Dejan used T03 I would ask him to try it.
Jan. As promised the FET question was raised at the pub. Johns point of view is that is matters in the same way as cars must do 155MPH ( even diesel these days ). It's the box that must be ticked. John said in the PA world FET's devellope hot spots and die without warning. For the pennies it costs they fit multiple devices for that reason more than others. John agreed with you that domestic amplifiers shouldn't need it. In non class D PA has reverted to bipolar.
Another point he made was that trying to make the output stage bomb proof seems to cause driver failiure. I asked why not use a high gain T03P/247 like C5200/A1943 as drivers? He didn't think they would have the gain. As a group in and out they could. Johns last project of this type was a Helmholtz coil and amplifer which is a few R load with massive inductance. I gave him Douglas Selfs book of recipes which he found very useful to simplify the design. Self refines the function of an amplifier down to the dominant single pole ( in principle ). Even so the amplifier took months of work. The back EMF being the problem. Simulation using SIMetrix found nearly all of the nasties. It didn't ice the cake and get reliability. John walked out of that company when the bean counters came in. The project 95% wrapped up. The test set costs $30000 +. He says they are nowhere near reliable yet. He did it to prove a point. The boss is not an engineer, although may have a degree in similar. The best way to prove it is to walk out. It's a pyrrhic victory. The boss even tried to win arguements about electronics. That would be like taking Einstein on, John is that gifted. Last he heard the amplifier had been completely redesigned and now is worse. Mostly the coil was the next design problem as the devices in the amplifier are best of type.
We did discussed if a bipolar collector resistor of 1R and 0R22 at the emitter could be useful rather than the conventional current limiter. The jury is out on that one. It won't work exactly work like a FET. It might be better than the usual.
Jan your best point although I don't think you meant it is where is the Ron ( Rds on ) ? We can't say it's in the almost a collector . Nor can we say it's in the source like an external re . Actually it isn't very important. Looking at a bipolar device is looks very interesting to add 1R to the collector. If the analogy with a FET holds up it should work very well. Never seen it in a book. If Dejan used T03 I would ask him to try it.
Can you think of another way to do 0-60mph under five seconds ?
(or 50-75 in less than 4)
I have been to where you live and nothing moves just like Oxford. I am a 155 MPH car man in my heart. The Hybrids should do what you say. Hey, that's why to buy them. My old Honda 900 could do 3 seconds. The BMW 1000 twin was less than 6 and easy to do. It was their nothing special bike. Handled like a pig. The bikes are useless after 60 MPH, cars beat them. One paper not, reality is different if my size and weight. I am the Michelin man. Sill like Golf GTi mk1 most. Sorry Mr Moderator. Integrali most of all. You can do shopping in that one and win any street race. It has silly grip on cheap tyres. Dejan that's your baby. The Mrs would love it.
Sorry to risk car talk. As it's motors maybe allowed? See if that can be it for 2016 when posing this . The new VW Golf I think has a 30 mile range on battery ( motor = car = turntable ). VW think few owners will ever buy petrol. This is true as the petrol engine will give confidence to risk a journey. If only I had some spare cash I would buy one. VW in disgrace is the best time to buy. VW I fogive you.
Sorry to risk car talk. As it's motors maybe allowed? See if that can be it for 2016 when posing this . The new VW Golf I think has a 30 mile range on battery ( motor = car = turntable ). VW think few owners will ever buy petrol. This is true as the petrol engine will give confidence to risk a journey. If only I had some spare cash I would buy one. VW in disgrace is the best time to buy. VW I fogive you.
OK brake my rule. When I saw the Lotus Caterham guys years ago they said even a side valve engine in the earliest car had 7 to 8 seconds if midly tuned. That's engineering. Mostly the car was sold with I think something like the Kent engine. Not sure if the Anglia had it?
They thought the mildest tune engines gave the best fun. They liked the Rover K if the through studs working correctly.
I am well jealous.
They thought the mildest tune engines gave the best fun. They liked the Rover K if the through studs working correctly.
I am well jealous.
I've done the M20 to London and back lots of times.
Quite exciting when it rains, in particular during evening hours.
M20 must be short for sheer Madness, level 20.
Not sure it would have been such a thrill in a 4-wheel Coffin Chap-man.
https://www.youtube.com/watch?v=N-uyWAe0NhQ
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The Anglia had a very similar engine but most of them were three main bearing.
I think that the 1500cc version had gone to 5 main bearings (the cortina engine).
If this was the case, then that would be what became Cosworth's FVA
Four Valve Anglia ! Some references call up Four Valve A series.
and through umpteen iterations to FVC
It also spawned the Lotus twin cam where the L version of the block was basically a thick wall (more sand worn away?) bored to 1558cc.
Although Jim Clark had a very early (maybe the only one?) 1500cc version of the Elan.
Then Cosworth developed the DFV (Double Four Valve). Probably the longest lived dominant engine in F1 and adopted in various forms in many other formulae.
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This had the 4.7 original Shelby engine, T10 gearbox etc.
Was a factory production prototype.even went to the US in LHD form, then crashed into walls etc. Rebuilt on UK return. Tested at 4.2 to 60mph (no gear change necessary!). A pig in every way imaginable.....but an adorable pig. Pic is from mid 70s.....I've changed since then, except temper is probably worse!! And the car is now rebuilt to concours and is in Switzerland. [Lookie at tyres! Same as on RR....£180.00 each in 1975].
Was a factory production prototype.even went to the US in LHD form, then crashed into walls etc. Rebuilt on UK return. Tested at 4.2 to 60mph (no gear change necessary!). A pig in every way imaginable.....but an adorable pig. Pic is from mid 70s.....I've changed since then, except temper is probably worse!! And the car is now rebuilt to concours and is in Switzerland. [Lookie at tyres! Same as on RR....£180.00 each in 1975].
Attachments
The car above is the original Trident Clipper...a design from the very end of the first TVR company which was rescued. It was the fastest sub 7 litre road car produced for sale in the UK (at that time). The bu^@er would aquaplane and once spun like a top on the M3.but ended up facing the right way when grip was reestablished. [ I believe there is a sister - but in Au, not glass, - which is a drop-head and was factory badged as a TVR ]. I bought this one for £750.00 in 1973.
KEF says the LS50 has 0.4% THD under a fairly wide range of operating conditions:
http://www.kef.com/html/us/showroom/flagship_hi-fi_series/LS50/fact_sheet/LS50_group/LS50/index.html
Since a rather wide range of frequencies are specified, it is probable that lower values such as 0.1% may be obtained in the mid range.
0.4% is excellent. I knew it was near what I seek. Sounds very good to my ears with plenty of spacial imformation. I really should buy a pair. As they have things about them I usually dislike that's even more special. I might be wrong a metal tweeter. There is a resonance at about 32 kHz which I guess is fine. They look to have a plastic cone which is another of my hates. I really liked Celestion SL6. They also were my " hates " sounding very nice.
Nigel, if you interested in the LS50, you should try to get a listen to the Fostex GX100 Limited for comparison, although I gather that might be difficult. Here's a review where it is compared to the LS50:
6moons audioreviews: Fostex GX100 Ltd.
The price is listed as £2079 a pair, but I have found them in Japan for around £750.
Manufacturers list price is 100,000yen This site shows them for 65,480 yen = £372
‰¿Ši.com - FOSTEX GX100 Limited [’P•i] ‚̃Nƒ`ƒRƒ~ŒfŽ¦”Â
here's Fostex's page on them:
Google Translate
I'm tempted myself, just on the basis of the review above, my respect for Fostex, and the way they sound even through the primitive camera microphones used in a few Youtube demos like this (the piano is amazing):
https://www.youtube.com/watch?v=XlYObIagjdw
The advantages of magnesium over aluminium are obvious in this demo (at 1:50) where he drops the Al and Mg versions of the 4" driver's diaphragms on a hard surface. Fostex makes this speaker with Al tweeter and woofer for half the price:
https://youtu.be/wrdYofPYD4M?t=79
6moons audioreviews: Fostex GX100 Ltd.
The price is listed as £2079 a pair, but I have found them in Japan for around £750.
Manufacturers list price is 100,000yen This site shows them for 65,480 yen = £372
‰¿Ši.com - FOSTEX GX100 Limited [’P•i] ‚̃Nƒ`ƒRƒ~ŒfŽ¦”Â
here's Fostex's page on them:
Google Translate
I'm tempted myself, just on the basis of the review above, my respect for Fostex, and the way they sound even through the primitive camera microphones used in a few Youtube demos like this (the piano is amazing):
https://www.youtube.com/watch?v=XlYObIagjdw
The advantages of magnesium over aluminium are obvious in this demo (at 1:50) where he drops the Al and Mg versions of the 4" driver's diaphragms on a hard surface. Fostex makes this speaker with Al tweeter and woofer for half the price:
https://youtu.be/wrdYofPYD4M?t=79
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