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lgvenable
04-02-2010, 05:56 PM
I have a chance to get 12 8340's or 8330's from a theatre;

heres the question, which would be the best for side surround and fill, and rear surrounds; as I will be using 2206-2445/2385 mid horns, and a 2404 tweet in the front 3 channels.

I'd also be using Audessey Pro to eq them in my system.

JBL 4645
04-04-2010, 04:48 AM
lgvenable

Keep the surrounds the same for the sidewalls and rear wall never intermix them up otherwise the timber balance, will be way off.

Keep the surrounds mounted at the same height level on the sidewall and rear wall since you don’t have a rising floor with seating stepping up every 6” or so.

Wire them up in parallel and have so many for the sidewalls and rear wall amplifier.
With parallel you’ll notice the SPL db going up +3db each time so the amp will have to be turned down to match the SPL db, of a single front channel (otherwise the surrounds will drown out other sound frequencies (masking them and making it hard to understand what is happening over the LCR.

You’d only need less power to run them in close proximity over a large small to medium size cinema where they’d be mounted at least 8 feet up.

Four per sidewall and the spacing will be trail and error (as I leaned for the spacing of my smaller control 1).

Keep the back wall a tighter with the surrounds (don’t space them apart between the middle row seating) for centre back surround to work in close proximity. This will keep the sound image firm and solid without any gaps for listening on the centreline or slightly off the centreline.
In a cinema they will be space a bit further apart due to the distance of the back row of seating to the back wall surrounds which is at least 6 to 7 feet.

In the home you’re just that nearer to the surrounds on all-sides.

Measurer the sound with wideband pink noise and use an RTA with SPL db metre.

The surrounds should equal the same frequency response as single front channel.

You might want to check each surround speaker placed on table and test each one with (wideband pink noise) and RTA with SPL db to make sure they are in tiptop working order.

Mount each surround up one at time per sidewall and test them out.

For optimum easy of placement I strongly recommend attaching a straight timber beam along the sidewalls and back wall at the same height level.

This will make mounting easy and if the surround doesn’t fit in with its placement over the seating area it shouldn’t take no more than a few minutes to relocate the surround speaker.


Just make sure you use thick screwing or coach bolts that go in deep into the wall to hold the timber frame and the four surrounds, otherwise it will come crashing down in the dead of night!

The idea of direct surrounds and the spacing is to cerate a defocused defused and uniform surround over costly expensive dipolar/bipolar surrounds.

The uniform surround will defocus the monaural surround on
Dolby stereo pro-logic for a wow, wow surround
Dolby digital 4.0 / 4.1 / 5.0 / 5.1 some films have discrete monaural surround depending on the year they where made

While keeping the (centre phantom) monaural half of the sound, sounding like an in-head sound, with all types of surround channel, even stereo surrounds will have in-head feel and directional stereo panned effects on the surround should (((whoosh))) past one side and the other side with thrilling realistic results, just a it does in cinema.

Scroll down near to the bottom where it says: G (Surround Requirements)
http://www.jblpro.com/pages/pub/cinema/cinedsgn.pdf

Lenaed Audio education Cinema
http://www.lenardaudio.com/education/17_cinema.html

Lenaed Audio education Cinema A chain B Chain
http://www.lenardaudio.com/education/17_cinema_4.html

You might find that EQ may take a few days unless that Audessey doesn’t entirely screw the whole sound right up as I’ve read on some forums.

lgvenable
04-04-2010, 04:36 PM
All are about a year old, and look brand new. I got six 8340's for my church. They 're a little older but they'll handle more power each; and we can use it there >> as I have 4 crown amps at 500 wpc. ;)
Larry
all at a bargain price of 50USD each; and they're all in perfect shape. :D

hmm the spots must be on the camera lens

lgvenable
04-04-2010, 04:43 PM
these resources mention mounting 8 feet up, or should I mount the speakers between sitting height (8 ft) and standing ~10ft?
Larry

JBL 4645
04-05-2010, 04:03 AM
these resources mention mounting 8 feet up, or should I mount the speakers between sitting height (8 ft) and standing ~10ft?
Larry

Larry

Yeah my cheap digital camera often produces spots just in fact exactly like the ones on you’re picture, weird huh?

The grills and sides of the baffle wow I’m surprised they are intact.
What’s the condition with the grills removed.

You got enough power I thought you, was going to run them off a common AVR LOL. 500w should be plenty.

Oh, they’re going into a church and how appropriate. JBL Jesus Blessed Lord will surround them! :D

How long is the church from front to back?

You might need a few more.:D


these resources mention mounting 8 feet up, or should I mount the speakers between sitting height (8 ft) and standing ~10ft?
Larry

A visual picture of the church from front back and side to side angles might show a clearer perspective of where they should be mounted.

I’ve seen some churches from the inside and some have pillars, others have straight narrow walls, they all have different look to them.

jcrobso
04-05-2010, 08:07 AM
"JBL Jesus Blessed Lord will surround them! :D"

Can you supply a floor plain?

JBL 4645
04-05-2010, 10:44 AM
I think it’s kinder of catching myself.:p

So do you have any ideas on how they should be fitted because, I can’t see though walls?

Whew loudspeaker cable is another added cost some good high strand will have to be used between the amps and loudspeakers.

rlsound
04-05-2010, 05:02 PM
They are more than a year old.

Those are the original 8330s, which were replaced by the plastic 8330A. They were last in production around 1998-1999.

lgvenable
04-05-2010, 05:44 PM
however they look nearly new. I'll post a front off shot. They might need surrounds in the next year or so, but I have enough to user 8 in my theater room as surrounds, and I'll be getting black grill cloth from SAEMAN.


I am getting another 8 of the 8340's Saturday (50 bucks each!!)

We have 6 walls in the santuary, but with the stage the floor looks like a pentagon. I'll post some pictures, and, and am you guys can give me some help. I do the sound there & am slowly building A REAL sound system
mixer = Mackie 32-8 VLZ Pro
amps = 3 Mackie number will follow... 500 wpc
also 2 Peavy CS800X at 275wpc into 8 ohm
mics
all Shure Carotid pattern except those above the choir

pic to follow, any help appreciated

rlsound
04-05-2010, 07:51 PM
That's a very good deal!

Make sure you have them secured well to the wall. The 8340s are extremely heavy and will cause damage if they fall ( or seriously injure someone underneath )

lgvenable
04-05-2010, 09:40 PM
Here's the front shot of an 8330 is, the surrounds look new, no foam rot apparent, the 8340's might need a refoam in the next two or three yrs. Oh, and they sound great!

JBL 4645
04-07-2010, 05:39 AM
That’s the thing! You fit them in the church and you’ll be up on step ladder every few months removing the grills to inspect them the bass mid and mid range driver.

Rubber surround yes its longer lasting and JBL knows this. I think they should implement new rubber surround on all cinema surround speakers. I mean look at the home HI-FI marketplace today, most new JBL speakers have edge rubber surround.

One other way of checking is to put a bright touch light behind the bass mid and mid range is bit hard I think it will show if there are any fractures.

You could do this from the front but its bit noticeable from the opposite side.

So this means undoing the speakers and will take about 2 minutes to unscrew the four screws and then ply the speaker with a little leverage as it would be a little stuck due to the years being attached to the enclosure.

So you’re looking at nearly 4 to 5 minutes per 8330 then inspecting with bright touch beam to see if the foam is secure.

You’re looking for hairline fractures often they run around the curvature of the foam surround or sometimes along its width.

Rubber surround rules!


Other then the picture you’ve shown, it looks sound to me, but its slightly fuzzy on the image and that will mask any possible hairline cracks.

Mate, it looks sound to me. Got pictures of the other 8330 with the grills removed.

Hmm, the 8” bass mid driver is part of another JBL Hi-Fi speaker is it not? I noticed TLX on the tweeter and that is part of the JBL TLX series.

http://www.freeadsonlineuk.com/_mm/_d/_ext/21515/big_Jbl%20Tlx%203%20Gi%20Speakers%205001.jpg

Is it possible that the parts of the 8330 are from the JBL TLX 151 or 171.

http://www.arciapleteam.com/foto_album/albums/userpics/varie/10001/tlx8.jpg

Although the mid ranger driver is different on this model the dust cap is not the same as it is on the 8330. Also the bass mid driver isn’t the same or same look?

Nope it’s not a JBL control 5 plus driver as the cone is white on the 5 plus.

Even the JBL 8330A uses the same component drivers, expect the enclosure is a plastic moulding. This model is lighter in weight with more or less the same frequency response specifications.

http://www.jblpro.com/pages/cinema/8330a.pdf

http://www.ltt-versand.de/shop/images/jbl_8330a_433x462.jpg

http://www.fullcompass.com/common/products/lg/46215.jpg

lgvenable
04-11-2010, 07:34 PM
Hence the speakers will all never be driven like they are in a theater. All of the 8330's were recently serviced by the theater they came out of. Close examination reveals no stress cracks etc what-so-ever. The surrounds look perfect. However good idea, I'll take out each driver and backlight them.

In an ordinary service, I'd be surprised if the speakers see more than 30 watts continuous. Certainly they'll never see 80 to 100, as the volume level would be way too high. And that's in the musical part of the service. There's no where near as much use in the sermons (5 to 15 wpc ); as you'd boom out extraordinary levels if you turned up the volume that loud. The sanctuary is a 350 seat venue.

lgvenable
04-11-2010, 07:48 PM
Hmm, the 8Ē bass mid driver is part of another JBL Hi-Fi speaker is it not? I noticed TLX on the tweeter and that is part of the JBL TLX series.

http://www.freeadsonlineuk.com/_mm/_d/_ext/21515/big_Jbl%20Tlx%203%20Gi%20Speakers%205001.jpg

Is it possible that the parts of the 8330 are from the JBL TLX 151 or 171.

http://www.arciapleteam.com/foto_album/albums/userpics/varie/10001/tlx8.jpg

Although the mid ranger driver is different on this model the dust cap is not the same as it is on the 8330. Also the bass mid driver isnít the same or same look?

Ash
the pdfs indicate a different part number for the TLX171 and 8330 tweeters.

lgvenable
04-13-2010, 08:50 PM
Final count JBL8330's....18
JBL8340's....12

All at 50.00 each!

Here's a pic of 6 of the 10 8340's I'm keeping for my side surrounds and rear surrounds. Heck at this price, I might keep the entire twelve pack.

They're too heavy to place the other six with these, but they are all prime. The 8340's seem a little older, as some of the 8330's looked like they were new old stock. I guess I'll watch the surrounds on these and replace them all over the next year or so.

At any rate..a bargain, two weekends @ 2.5 hours each and a couple of fully loaded runs in my F150 Supercrew.

Too cool. I'll have best surrounds in this part of Indiana. The wife and I went to see "The Wolfman" last month, what did they have on the walls??

8340's just like these.;)

gsxronax
01-20-2011, 10:52 PM
Hence the speakers will all never be driven like they are in a theater. All of the 8330's were recently serviced by the theater they came out of. Close examination reveals no stress cracks etc what-so-ever. The surrounds look perfect. However good idea, I'll take out each driver and backlight them.

In an ordinary service, I'd be surprised if the speakers see more than 30 watts continuous. Certainly they'll never see 80 to 100, as the volume level would be way too high. And that's in the musical part of the service. There's no where near as much use in the sermons (5 to 15 wpc ); as you'd boom out extraordinary levels if you turned up the volume that loud. The sanctuary is a 350 seat venue.