Film-Tech Forum ARCHIVE: Switch on JBL 8340

This is topic Switch on JBL 8340 in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.

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Posted by Antonio Marcheselli (Member # 373) on 09-27-2000, 05:15 PM:

Hello everyone

What is the switch locate on the JBL 8340 Surround speaker? Has two position: "Cinema surround" and "ISO [something]".

Bye
Antonio

Posted by Gordon McLeod (Member # 33) on 09-27-2000, 07:43 PM:

It selects wheter the speaker has a flat response or a ISO rolloff

Posted by Russ Kress (Member # 461) on 09-28-2000, 12:40 AM:

It means that either the speaker is being used as a cinema surround, or a stage monitor in a live application.

Posted by Christos Mitsakis (Member # 143) on 09-28-2000, 07:28 AM:

ISO 2969. Its the X curve that the front speakers are equalised.

Posted by Antonio Marcheselli (Member # 373) on 09-28-2000, 12:14 PM:

So In "ISO 2969" the 8340 has the same frequency response than the front channels.

And in the "cinemna surround" what changes?

Bye
Antonio

Posted by Russ Kress (Member # 461) on 09-30-2000, 12:17 AM:

"Cinema Surround" sets a roll-off similar to the ISO standard for cinema applications.

The other position is used when the speaker is used as a full range stage monitor.

In both cases, I think that the idea is to have the speaker perform naturally correct in each application with a minimum of equalization.

Early cinema processors lacked surround channel equalization, so I am assuming that this option was intended to correct for this.

Contact Lonny or Ken at Dolby Laboratories, 415-558-0200 and they can tell you everything you ever wanted to know about this!

Personally, I think that the next Dolby tee-shirt edition should bear their likenesses!

Better yet, have seperate Lonny and Ken tee- shirts! Collect the whole set! This will be bigger than Pokemon!!!

Now, where did I put Ray's number!? (LOL)

Russ

Posted by Antonio Marcheselli (Member # 373) on 09-30-2000, 03:55 AM:

So, having a CP500, should this switch stay at "Cinema Surround" or "ISO 2969" position?

Bye

Antonio

Posted by Ian Price (Member # 14) on 09-30-2000, 01:11 PM:

Cinema Surround!

Posted by Antonio Marcheselli (Member # 373) on 09-30-2000, 06:02 PM:

Thanks Ian and sorry if my question was obvious...
But when I started my job for the first time I discovered that my theaters had all speakers with switch in "ISO 2969", wrong digital delay (after 5 year of installation), wrong DTS levels ("they haven't to be adjusted" said my ex tech...), wrong equalization and more...

Thanks to everyone!

Antonio

Posted by Rick Long Jr (Member # 541) on 10-11-2000, 09:59 PM:

Antonio; You asked "cinema surround OR ISO 2969". I believe if you look again it will say "cinema surround-ISO 2969" in one position and "flat-foreground music" in the other. Bottom line is ,you want Cinema surround, which is ISO 2969.

Posted by Antonio Marcheselli (Member # 373) on 10-12-2000, 05:15 AM:

Rick,

I saw that switch only few times, thanks for your help!!

Antonio