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New Member thank you plus questions!

#1
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10/26/09 at 2:00pm
  • Joined: October 2009
  • Post Count: 4
Hi there and thanks for all the shared thoughts and ideas on this site, glad I found it.

I am setting whole house audio and home theatre this month, and am in the process of gathering my cable, speakers etc.

Can anyoneplease share their input on the JBL control series speakers?  I am thinking a control 19 sub and using control 24 for my theatre and whole house audio.  One question I have is I have no idea what 70v and 100v systems means....can someone enlighten me?  Thank you!

Aaron
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#2
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10/26/09 at 4:00pm
  • Joined: May 1999
  • Post Count: 1,366
Okay, hopefully this is two separate issues.

First, the less subjective.  Normally, you run one amplifier channel via one wire-pair, to one speaker.  This is best-quality (before you go into the esoterica,) and cumbersome when you start talking whole-house sound.  Or PA systems.  Or shopping-center systems.  There, they take the signal coming out of the amp, bang it through a transformer into a 70 or 100v carrier voltage, and distribute.  At each speaker, there's another transformer, and depending on how the taps are set, provides an at-speaker level control (many have multi-tap transformers.)  And, for each "zone," you run one wire-pair to each speaker in the zone, in parallel.  (That is, if you've a red and black wire, you run the red wire to all of the red speaker terminals, and then the black wire to all the black speaker terminals.)

Older systems had some significant bandwidth limitations -- the closer you got to the carrier frequency (the AC line-voltage) the harder it was to filter out the carrier signal.  Plus, the closer you got to DC (as in, low frequency,) the more it saturated the transformers and made it... not work.  So in general, 70/100v systems didn't do low-frequency well, and would generally start rolling off at about 80Hz.

I've heard that that is changing, but haven't worked with a new system, so, don't know.

As far as JBL, well, some people really like 'em, some people really hate 'em.  They might be fine for the house-at-large, but I don't think I'd put them -- especially not 70v -- in a home theater setting.

Leo
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#3
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10/26/09 at 8:17pm
  • Joined: October 2009
  • Post Count: 4
Thanks Leo- I appreciate the input.  I have heard that you can bypass or "remove" the transformers and just use the speaker as a normal speaker....thoughts on that?  Anyone?  Thank you all!
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#4
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10/27/09 at 4:49pm
  • Joined: May 1999
  • Post Count: 1,366
Speakers are speakers.  Some, however, are easier to bypass the transformers than others.  Some are down-right impossible -- particularly the all-weather type, where it really is a sealed box. 

Leo
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