Which is why you use proper, enclosed subwoofers to handle the bottom end - Pete, the chap with the DEQX unit, has got a good handle on it, the most "intelligent" bass I've heard in a long time ...
The experience with the Steinway Lyngdorf Model D showed the other side of the coin, trying to do OB bass with a massive array of drive units. This was the most ridiculous thing I'd heard in years, I'm sure with some music I wouldn't even have recognised what was playing - the sort of thing that gives "high end" a bad name.
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Sad, it's obvious you are capable of some real technical discussion but it is just not happening here.
An OB is also hard to do well for bass..... front-rear signal cancellation affects.... room location from walls..... drivers easily over-driven if not careful in choises.....etc. For deep bass performance the closed box has the least number of ills (lower group delay also... important at low freqs)
THx-RNMarsh
THx-RNMarsh
The weird thing about OB speakers is to my ears they are the only speakers that have bass . The best example is my OB's went to one note bass the other day . Then I realized it was the sound of the guitar amp the other side of the microphone . What I would say is that the bass has thousands of notes which are usually given as a few . I miss the bang of a bass transient on my body , it is so obviously not there . 30 to 80 Hz with something nasty will probably be the next move . Noted the comment about bass decay . In my mind I predicted it and didn't get too much . Usually the cone bottomed before that problem arrived I suspect . If a box speaker doing this it would be hopeless . Thus the poor bass we hear in EQ'ed box speakers is the box being shown to be bad or worse than without EQ . We never say RIAA EQ is bad as it reveres a curve introduced in the recording . Also OB EQ is fine up to the point where the cone says too much .
My daughter is Ashburgers autistic . She came to listen many times in between doing girl stuff . Instead of just listening her eyes dart everywhere as she listens . For the first time in her life she said " keep them " . Unlike most listeners she is on a journey rather just enjoying . She was tested by Oxford University . Her hearing is about 300% better than average ( yes , 300% they said ) . OU have a hypothesis that autistic people hear better . Anything whispered by me the other side of the house she hears . She often repeats it and that can be trouble !!! People with William's syndrome also . William's is like Downs with different outcomes as it is not the same gene .
My daughter is Ashburgers autistic . She came to listen many times in between doing girl stuff . Instead of just listening her eyes dart everywhere as she listens . For the first time in her life she said " keep them " . Unlike most listeners she is on a journey rather just enjoying . She was tested by Oxford University . Her hearing is about 300% better than average ( yes , 300% they said ) . OU have a hypothesis that autistic people hear better . Anything whispered by me the other side of the house she hears . She often repeats it and that can be trouble !!! People with William's syndrome also . William's is like Downs with different outcomes as it is not the same gene .
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A good sign ... she's listening to the little music happenings that are part of the big picture - that's why they call it a "soundstage", this can become immense with some recordings, a cavernous 'theatre' that can easily swallow your whole house - or so it subjectively manifests ...
I never noticed this negative . I just think Mr W takes some warming up . Maybe the brightest bunny here ?
Frank you never saw such a thing . Like a drug and more . Come to think of it we all understand that don't we ? I have a few health issues which seem frozen now . It is only for her that I care . I suspect she will be 40 when fully grown up . Rather selfishly I like having her around . The French called them " Les idiot savant " . The idiots who understand is how it is badly translated . The special autistic people are called " Savants " . It is a corruption of the original .To my way of thinking all people are deaf , blind and autistic to varying degrees . Some says that the natural way of a man ( not to multitask ) is a sign of autism . Men are more often " obviously " autistic when they are . If the lady who does our Sky at night program isn't I will eat my hat . By strange chance most autistic people I know are women . That's most likely because women given the chance would be my number one hobby . I suspect just as many or more women are autistic as men . Many are undetected and suffer many problems as a result .
I failed to say Emeline's pitch perception is exceptional . This was done by playing a tone and giving many minute variants . She always picked the right one . No visual signs given when she was right . Again when doing it she was highly animated as it was like doing a puzzle . I was allowed to be with her to see the first 30 minutes .
I was very lucky to have a hi fi friend who is a psychiatrist . He advised me how best to get help for my daughter . We did something very unusual for the UK . We had her assessed by both the education and health system . We then passed notes between the two . Apparently this never happens . The two sides even enjoy knowing the other . Bit like Pro Audio and ourselves . Oxford is also the best place on Earth to have this problem . I would suspect at least 10% of the hyper intelligent I see in Oxford are Savants . I would call this passive acceptance . 100% of Oxford University Press perhaps ( Dictionaries ) ? The interaction meant she was drawn into the test programs . Baron Cohen is brother of the comedian Sasha Baron Cohen . He is an autism expert . And what of Sasha ?
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It seems I am more ambitious than you are, Frank. Your 200 kHz closed loop rule in my book reads as at least twice that. That is BEFORE applying the input filter, which then limits this to 200 kHz. That way, the amp is always faster than the fastest signal at the input.
Although, to truly eliminate speed as a factor of distortion, one would need to position that input filter just below the OPEN LOOP bandwidth, thus eliminating NFB delay as a factor.
As for local compenstation, it is a fine dance indeed, soaks up time like a sponge, but in my view, well worth the time and trouble. Not to even mention the wonders it does for general stability.
Actually, I think we agree, thought we put it differently.
Local feedback is a great idea, but as any good idea, it might be ruined by odd procedures.
Take an extreme case - one has one's VAS running with a gain od say 60 dB and then one applies feedback to it to get it down to say 30 dB. This begs the question why in hell did you have it amplify so hard in the first place?
The answer is usually that somebody was trying to put the VAS transistors into a near ideal linear mode. So he makes them work their heads off, yet evetually you come to the REAL answer - there was no real esate place and no money to bias it to say 10-12 mA per trannie, by which time it would have gone as linear it ever would, but would also need local heat sinks, because it is probably dissipating anything from 800 mW to 1.5W.
Then the matching and selection of VAS transistors. It usually comes down to the base C of the last transistor, if it's low it will rock, if it's high it won't do very well. But testing transistors for that is no short cut, quite to the contrary, it takes time and money to be done properly.
And it's not like people are unaware of this, quite to the contrary, Bob Stuart talked a lot about it in his Lecson days (first half of the 70ies).
Granted the sound is very nice without box colorations...... For bass under 100hz, the CB or a very large CB 'infinite' baffle works very well without many serious issues to deal with.
Having said that, the best sounding bass speaker I heard was a multi-driver OB from floor to ceiling size. So, I know it can be done. Second to that was my rear loaded transmission line bass using 18 inch driver. All-in-All, today, I would use the smaller CB for <100Hz. I hope to hear a HiPerf CB with 18 incher this summer at home..... assuming I get back outta here (still in S.E.Asia).
THx-RNMarsh
Might just throw in a point about the DEQX unit, Pete wasn't happy with the sound of it when first purchased, threw away the silly SMPS supply it came with, and added a very solid linear supply to very markedly improve it. Of course, in the meantime the later versions of that device, from the factory, have been similarly upgraded ...
Mostly my OB sounds good . Often the bass better than usual ( industry usual ) . 10% of the time it is hopelessly wrong . I think I can close the gap . Real pipe organs do not sound good in the mid band without bass ( yes ) . Thus everything should benefit . I will look at the Celestion OB sub-woofer . It might have what I need . I will build 2 .
A friend who heard a Graham Holliman demonstration was knocked off of his feet . He stated it had nothing to do with bass , just open sound . Sub woofers were mostly unknown then . Time delay apart why not ?
Build an Infrasonic Subwoofer
BTW . I have heard more high end than many . Usually it sounds weird . The point seems to be to make one aspect rather good much in the way of a special lens in photography . The designers seem oblivious to the ugly side of what they have built . I suspect I have slightly fallen into the same trap . As I am not trying to persuade anyone to follow me so where is the harm ? I know for a fact there is a bump at 7kHz to 12 kHz ( + 4dB 10 kHz with +/-2 dB ripple , by maths and sounds that way ) . My theory is very little accuracy required as long as it is low distortion apart from amplitude , what real tones really live there ? Pickups are far worse and sound fine , they have tonal balance but not to the point where changing seat at a concert wouldn't do worse ( been there , done that , thought a seat was vacant ) . Either side of that ruler flat ( really ruler flat ) . The silly thing is the 30 degrees off axis doesn't have the bump . I feel it is a good characteristic and should live with the bump . What it mean is stereo is very good . I think I might say the first time in my life I every heard the real deal stereo . This completely contradicts predictions of OB defects . Fluke is my guess . I have 5 degree back tilt on the baffle which sits on chair backs for the moment . Hope the chairs ain't doing the magic .
Looked at Cambodia for a holiday . Nothing too interesting yet . Thought of you . Mid Vietnam August 24 th was also mentioned . I think Sri Lanka is the likely winner as it has direct flights . Dvv , myself I prefer Somerset . However I am not Colleen . Your near neighbour country Croatia is beautiful ( very ) . Flew up the coast once and all looked the same . Very good local wine made with Zinfandel as a red wine wine peppery overtones ! Croatia claimed to be the origin of this Italian-Californian grape . I don't do well with red wine so it is high praise and no thumping headache .
Late to do something so please allow for errors .
http://blog.sciencemuseum.org.uk/in...ntroducing-britains-largest-horn-loudspeaker/
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That's my job these days --
..... both stuck and just goofing off. Started with a week on the Mexican coast for R&R in prep for the Asia trip. Will end it with R&R at a sea side spa the last week in prep for trip back to California. Everything in between R&R's was R&R, too. I can feel my mind turning to mush. How can the wealthy do this every day of their lives?
But I got my girls and family in Nepal a new LED flat screen TV to replace their first TV I got them 10 years ago (still CRT), and a really big UPS for those hours when they have no electricity everyday/evening (hanging some light bulbs off the UPS, also) and new cloths, a vacuum cleaner, back packs for all and kitchen appliances and swimming and great food for them at my resort place etc etc. An all nude massage and scrub for the mom..... made her feel wonderful. And, lots of xoxoxo. Mom, dad and kids always cry when I leave.... we always have fun together. I brought my own company along - Patti and Lisa - with me. I felt like a king. That's my job these days.
-Richard
..... both stuck and just goofing off. Started with a week on the Mexican coast for R&R in prep for the Asia trip. Will end it with R&R at a sea side spa the last week in prep for trip back to California. Everything in between R&R's was R&R, too. I can feel my mind turning to mush. How can the wealthy do this every day of their lives?
But I got my girls and family in Nepal a new LED flat screen TV to replace their first TV I got them 10 years ago (still CRT), and a really big UPS for those hours when they have no electricity everyday/evening (hanging some light bulbs off the UPS, also) and new cloths, a vacuum cleaner, back packs for all and kitchen appliances and swimming and great food for them at my resort place etc etc. An all nude massage and scrub for the mom..... made her feel wonderful. And, lots of xoxoxo. Mom, dad and kids always cry when I leave.... we always have fun together. I brought my own company along - Patti and Lisa - with me. I felt like a king. That's my job these days.
-Richard
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