Browsing the old internet?

dl324

Joined Mar 30, 2015
12,451
The problem is not in today's hardware but in poorly written software.
Couldn't agree more. Google is the biggest memory hog on my computer. Often over 1GB of memory (for browsing!!). And GB's of local storage that never gets cleaned up (AFAIK). I was searching for what was taking up so much space when I couldn't do a software install and found over 3GB of .tmp files from Chrome...
 

wayneh

Joined Sep 9, 2010
16,790
I just installed Office 2016 and was aghast that Excel is now 1.71Gb. Worse, PowerPoint is 1.61Gb. How is that even possible?

I remember using Excel on a floppy before it became version 1.0 and Microsoft bought it.
 

Fmrx

Joined Jan 28, 2015
28
I have to say Google search isn't the way forward .we all search for the right things it brings up a bunch of different things to what you want to see .back in the days when altavista were my ideal search provider it had things I was looking for .its as if Google are destroying all the sites so it shows all the top marketing crap .i still search with altavista they have things we want to see like for instance in the 90's ,and old circuits schematics .google just constantly throw the same crap on nearly every site that pops up .
 

AnalogKid

Joined Aug 1, 2013
8,939
I am working on a cassette recording project which will help to create higher quality recordings of music. For example, AC biasing will be added to the audio output to help with hysteresis and filters will be used to help match the audio with the frequency response of a cassette player.
AC bias for audio tape recording was invented in the 30's, was commonplace in high-end pro gear in the 40's, and was standard on all pro and much consumer gear in the 50's. Asia gave us cross-field and Ampex dabbled in squarewaves, but even dictating machines (the thing Philips invented the audio cassette for) had bias. I'm all for old-school designs (duh), but am I missing some context for your statements?

ak
 

Robin Mitchell

Joined Oct 25, 2009
819
@AnalogKid

I am not sure if my tape decks apply bias. I have three shoe box cassette players which where primarily for saving computer programs. I also know that when you record onto vinyl you increase the amplitude of high frequency sounds and reduce it on the low frequency sounds. This is due to the fact that vinyls dont record low frequency sounds too well (I think it is actually more to do with cutting in the plastic). So when they play back the sound they apply the same filter but in reverse so low frequency sounds are amplified a-lot.

So my thinking is that maybe the same applies to a cassette recorder. The low frequency sounds are easier to store (as the magnetic compounds are a finite size), whereas higher frequency sounds are harder to store. I dont know the actual frequency response for cassettes but I would like to experiment with it :)
 

wayneh

Joined Sep 9, 2010
16,790
I don't think it's possible that you could have a tape deck that did not apply bias. And you have the RIAA curve backwards. It applies pre-emphasis to higher frequencies while recording and de-emphasizes on playback, which helped to reduce high frequency noise. I think Dolby NR did much the same for tape.
 

AnalogKid

Joined Aug 1, 2013
8,939
I think Dolby NR did much the same for tape.
Sorta. First, the audio recording tape structure has its own pre-emphasis/de-emphasis corner frequencies and networks, called NAB (National Association of Broadcasters) equalization. Like the RIAA (Recording Industries Association of America) curves, they are derived primarily from the fact that a recording head, like the cutting head for a vinyl record master disc, is an inductor. The voltage/current range of a constant loudness signal across an inductor from 20 Hz to 20 kHz was too large for the mechanical assemblies and the electronic circuits of the 20's and 30's, so the curves were developed to standardize an approach to limit the range. This equalization system does suppress high-frequency noise in the recovered signal, but that is a secondary benefit. Few remember that European countries had their own equalizations curves that were different, and high-end tape gear had a switch to select NAB or IEC eq.

Dolby is all about noise suppression only. While it is another pre-emphasis/de-emphasis system, it adapts itself based on the volume of the signal (unlike the NAB system which affects signals of all volume levels equally). This is why you have to know if the source material was Dolby encoded in order to adjust the playback system correctly. One way to think of Dolby Noise Reduction (DNR) is as a multi-band compressor/expander.

AND - Ray Dolby was a circuit design wizard/genius/god, one of the five "inventors" of broadcast-quality videotape.

ak
 
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atferrari

Joined Jan 6, 2004
4,197
Not always.
I hated my job fixing TV's so much that I still occasionally take one out to the concrete and beat it to death with a hammer.:D
But as far as I can recall, every time I've read your comments about that job, you seemed proud of being able to do it... I think I would also be so, if in your shoes...! :)
 

AnalogKid

Joined Aug 1, 2013
8,939
@AnalogKid I am not sure if my tape decks apply bias. I have three shoe box cassette players which where primarily for saving computer programs.
If you are talking about the Kansas City Standard, then most small cassette players of that era did apply AC bias during recording.

So my thinking is that maybe the same applies to a cassette recorder. The low frequency sounds are easier to store (as the magnetic compounds are a finite size), whereas higher frequency sounds are harder to store.
A record/playback magnetic head is like a horseshoe-shaped electromagnet, and the tape travels across the gap between the ends. Recording takes place at the trailing edge of the gap, so gap geometry does not affect greatly the ability to record low frequencies. However, playback is determined by the change in flux across the width of the gap. As frequencies get lower the recorded wavelength on tape gets longer, so the change in flux per milisecond decreases. Thus, low tape speed limits low frequency response, and at 1-7/8 ips, cassette tape speed is very low. As frequencies get higher, the recorded wavelength on tape gets shorter and shorter until it approaches the width of the gap (at which point there is no output). So head geometry limits the high frequency response. The finite size of the magnetic particles directly affects noise, but not bandwidth.

ak
 

AnalogKid

Joined Aug 1, 2013
8,939
Only because I lived through it. Back in the 70's I worked nights and weekends in a TV station videotape room. Young, restless, and bored, two of us took 4 years to build a broadcast-quality videotape machine. We started with an old RCA TR-22 mono clunker, kept the frame, the transport deck and the motors, and rebuilt everything else with contemporary techniques and components: Linear and switching power supplies, motor drive amplifiers, three servos, record amplifiers, switched low impedance head preamps, audio and FM video signal chains, dropout, timebase and phase correctors, sync and proc amps - everything. Had a blast.

ak
 

wayneh

Joined Sep 9, 2010
16,790
But as far as I can recall, every time I've read your comments about that job, you seemed proud of being able to do it... I think I would also be so, if in your shoes...! :)
Being proud of once learning FORTRAN doesn't mean you would enjoy doing it again Even if I could remember more of it than I think I do, I'd rather not. My kids can't use a phone book. I can, but I throw them away when they arrive.

Plenty of new stuff to play with. I don't need the old.
 

#12

Joined Nov 30, 2010
18,217
But as far as I can recall, every time I've read your comments about that job, you seemed proud of being able to do it... I think I would also be so, if in your shoes...! :)
Looking back, I think it was spectacular that I could fix color TV's as my 40 hour job when I was 19 years old.
The other side of the coin is that I was in over my head (technically) and I didn't know I had choices in the electronics industry. Every day was a screaming 100 yard dash learning the circuits I was working on and learning the new models as fast as they came on the market. On top of that, my customers only knew what the sign over the door said: "Satisfaction guaranteed or your money back."

A good example:
One of my job tickets said the customer was deaf. I thought, "Excellent. They can't insult my intelligence and the sound quality doesn't matter."
Wrong. Both times.
They questioned my competence in writing and they had a friend who visited and he knew the sound was wrong.
The TV was easy enough to fix, but those customers, and many others, drove me up the wall.

That was in a place where there was no industry, just home owners and retail sales.
When I moved to California, I was able to get factory jobs where I didn't have to talk to anybody. I was free to hyper-focus on the job and learn as fast as I was able. That was nerd heaven compared to trying to fix people!

After I learned that I'm mostly nerd and almost zero Public Relations, I forever after positioned myself with a layer between me and the customers. I presented myself as a technical specialist with other corporations and took a helper on my own jobs. I did calculations and design work which I could present on paper without saying a word. My "helper" was only there to keep the customers occupied while I diagnosed and fixed the machines. You see, I can fix electronics, I can't fix people. Here on AAC, I have the Ignore function. That's my protective layer. If you need technical help, I can do that. If you need your attitude fixed, I have the Ignore function.
 

MaxHeadRoom

Joined Jul 18, 2013
22,346
One of my job tickets said the customer was deaf. I thought, "Excellent. They can't insult my intelligence and the sound quality doesn't matter."
Wrong. Both times.
They questioned my competence in writing and they had a friend who visited and he knew the sound was wrong.
Britain was the first to transmit residential TV reception and many of the early sets were a little crude, but one customer had one tech stumped when she told the guy she was getting last weeks programs.
On questioning he found that when she compared her favourite soap to her neighbor, her neighbor was a week ahead with the plot.
After trying to humour her to no avail, he spoke to the neighbor and all came clear.
The spot they were both located in was on the fringe of a London transmitter and a UK midlands transmitter, anyone in the area had the choice of picking which station to pick up.
Each neighbor had different stations and the customers station showed the soap a week later.:p
Max.
 

Roderick Young

Joined Feb 22, 2015
408
Not always.
I hated my job fixing TV's so much that I still occasionally take one out to the concrete and beat it to death with a hammer.:D
Are you kidding? I LOVED fixing TV's, that's how I got my start in electronics. Everyone thought I was so smart. One girl told me that "if you can fix this for me, I'll show you how a girl thanks a guy."
 

AnalogKid

Joined Aug 1, 2013
8,939
We could go to Off Topic and make a Thread about insane customers.
When it comes to the frustrations of explaining technical things to non-technical people, the classic analogy is "It's like trying to explain color to a blind man."

No, it isn't. I've explained color, and sine waves and characteristic impedance, to a blind man; twice. Far more difficult, and sometimes outright dangerous, is trying to explain red to a colorblind man.

Depending on who you ask, around 8% to 11% of the US white male population has some degree of color blindness. More definitive testing under rigidly controlled conditions indicate that it's more like 33%. Most interesting is that the vast majority, particularly those with "just a touch" of color blindness, are completely unaware. Explaining some aspect of perception to someone who already knows that their perception of the reality around them is incomplete, or lacking, or deficient is relatively easy. It is far harder to convince someone who is sure that their reality is right and that their perceptions are accurate and true, that in fact they are missing something, that others *physically* see the world differently. Compared to that, winning an argument in this ultra-contentions political season is trivial.

ak
 
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