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"[book] gave us the secret ... sealed enclosure created two separate acoustic environments ... one inside the speaker enclosure ... and one outside, where the m

"[book] gave us the secret ... sealed enclosure created two separate acoustic environments ... one inside the speaker enclosure ... and one outside, where the microphones were" I would have thought that part of the design would have been self-evident? As a TRS-80 owner starting in 1979 I also morn the loss of the inventor/creator version of Radio Shack - hung out there often walking back from school and many started learning BASIC programming (which at the time included hand-assembling Z-80 code in read/data statements and POKEing them in) in the store.

dsr_ 10y ago
There are a lot of speaker designs. To begin with: how much power do you have available? If you need to depend on the power from the phone line, you need a very efficient speaker -- a horn design, most likely. If you have an external power source, you get a better amplifier, and you can use a less efficient dynamic speaker. What do you put it in? You can leave it unsealed; you can port it carefully; you can seal it in a box -- but what size box? Turns out that the characteristics of the speaker and the size of the box together determine the performance of the speaker.
- thelazydogsback 10y ago
  They weren't using the POTS line for power (though I remember holding the leads when a ring signal came in - quite a shock! - seemed like the NYC local-loops must have had a RI# of about 20 at the time...) -- and they weren't just building a speaker - they were building a speaker in the same enclosure as microphones, so physical isolation seems like it would be top on the list. (Though even that would have only helped with freqs <= a few hundred Hz, so their active cancellation would still be key...) No big deal - it just "seems" obvious, but I wasn't there...
- thelazydogsback 10y ago
  And, if they did hang out at Radio Shack, they would have come across the venerable Minimus-7 - one of the first examples ever of a high-performing micro speaker with a sealed-enclosure design, that still stands up to the test of time. http://www.retrothing.com/2011/06/minimus-speaker.html http://www.retrothing.com/2011/06/minimus-speaker.html
205guy 10y ago
> the design would have been self-evident > it just "seems" obvious I really don't understand what these comments bring to this discussion, or any discussion. Evidently, you were not there, and a person who was is telling us the story. Your opinion that the past facts don't align with your expectations is not relevant.
- thelazydogsback 10y ago
  If that's your opinion, then certainly your tertiary meta-comment adds even less value. I think it's truly interesting and worth looking at when, post-hoc, something seems like it should have been obvious, but was not. This can include, among many things, over-saturation of micro-problems in a small domain or slice of the problem limiting "out of the box" thinking on the creation side of things, or misunderstanding of the history and motivations of the creators on my side of things. I'm perfectly willing to acknowledge it may be the latter - but one also must acknowledge that a sub-enclosure for the speaker, whether to enhance the performance of the driver or help isolate the microphones (though I could be over-estimating the benefit of this) "seems" obvious. This does not detract from the story, which I like for many reasons, or the more important fact that a successful business was built, which takes a suite of skills and much fortitude.

dsr_ 10y ago

There are a lot of speaker designs. To begin with: how much power do you have available? If you need to depend on the power from the phone line, you need a very efficient speaker -- a horn design, most likely. If you have an external power source, you get a better amplifier, and you can use a less efficient dynamic speaker. What do you put it in? You can leave it unsealed; you can port it carefully; you can seal it in a box -- but what size box? Turns out that the characteristics of the speaker and the size of the box together determine the performance of the speaker.

thelazydogsback 10y ago
They weren't using the POTS line for power (though I remember holding the leads when a ring signal came in - quite a shock! - seemed like the NYC local-loops must have had a RI# of about 20 at the time...) -- and they weren't just building a speaker - they were building a speaker in the same enclosure as microphones, so physical isolation seems like it would be top on the list. (Though even that would have only helped with freqs <= a few hundred Hz, so their active cancellation would still be key...) No big deal - it just "seems" obvious, but I wasn't there...
thelazydogsback 10y ago
And, if they did hang out at Radio Shack, they would have come across the venerable Minimus-7 - one of the first examples ever of a high-performing micro speaker with a sealed-enclosure design, that still stands up to the test of time. http://www.retrothing.com/2011/06/minimus-speaker.html http://www.retrothing.com/2011/06/minimus-speaker.html

205guy 10y ago

> the design would have been self-evident > it just "seems" obvious I really don't understand what these comments bring to this discussion, or any discussion. Evidently, you were not there, and a person who was is telling us the story. Your opinion that the past facts don't align with your expectations is not relevant.

thelazydogsback 10y ago
If that's your opinion, then certainly your tertiary meta-comment adds even less value. I think it's truly interesting and worth looking at when, post-hoc, something seems like it should have been obvious, but was not. This can include, among many things, over-saturation of micro-problems in a small domain or slice of the problem limiting "out of the box" thinking on the creation side of things, or misunderstanding of the history and motivations of the creators on my side of things. I'm perfectly willing to acknowledge it may be the latter - but one also must acknowledge that a sub-enclosure for the speaker, whether to enhance the performance of the driver or help isolate the microphones (though I could be over-estimating the benefit of this) "seems" obvious. This does not detract from the story, which I like for many reasons, or the more important fact that a successful business was built, which takes a suite of skills and much fortitude.