Used JBL 8330 for large basement?

[Bd2e]

I am new here and to forums in general so hope I am doing this right.

I have been interested in Home Cinema for a long time, mid ninetys I guess when I was first blown away with Dolby Surround and set up my "cinema" in a bedroom. Cables everywhere and rubbishy rear speakers. I gradually improved as you do with laser players and NTSC discs @ £50 each just for the AC3 soundtrack. I currently have Mission 752s as fronts, 751s as rears a Kef 100 centre and a couple of REL 50W subs squeezed into the lounge. I moved (built a new) house with a basement specifically for my cinema. Lack of funds and 3 more kids (4 now) put the whole thing on hold.

The basement is dry but totally empty and the equipment I have is not going to put a dent into this space. It's a big rectangle 9.6m (31'6") by 8.4m (27'6") and 4.5m (14'9") tall - it was only meant to be 10' deep but the digger driver forgot to stop and decided to keep depth rather than pay for 1.5m of crushed rock.

Anyway, I am now looking at starting work on the basement and have found someone selling 8330's cheap. I am thinking of buying a load and using them solely for all channels giving me a good and cheap start. When funds allow I would look to first add subs and the replace them starting with the fronts. I am thinking 5 for rears l wall, l back, c back, r back, r wall, 2 for centres, 4 for fronts, 2 for front surrounds. Am I mad? Or maybe misguided and these come up all the time. They are £50 each so in my budget although will need to look at amps when I need to actually use them.

I would really appreciate any advise as this is pure guesswork at this stage. Thanks.


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[andyblackcat]

Well my, my what your getting yourself in for. Cheap yes and buy now before sold.

No only use for surround channels I see the idea is okay using them as matched all around but you'd be better off with them as the surrounds and another matched LCR bass cab and HF horns for stage channels 2-way is plenty enough even needs a bit of small taming the HF level down so its not painful like some cinemas that have poorly calibrated EQ that even forces me to cover my ears if it goes over 85dbA.

You'd need at least a good 6 each side wall spread evenly apart and 4 or 6 on the back wall but I'd go for 6 on the back wall and spacing them apart needs to be done with the calculations of the seating not critical but would help to know.

Height 7 or 8 feet up so its about half way of height of wall. (even thou my 8330 are close to ceiling and for reason unless I like banging my head on them when walking in) your room about 7 to 8 feet up. The angle 15 degree will beam focused surround around the finished room with uniform coverage.

Fitting them to the walls flush you can do it quick and easy with two metal steel plates and get a friend to hold it underneath while you screw them to the walls.

I can't find the older JBL manual that I have printed but the newer one [page 31] will give you some idea on wiring the diagrams are rough guild, I'd still go for 6 each side wall and 6 on back wall to give a tight surround.

You can also fit them to the ceiling for OVERHEAD SURROUNDS but would require removing the bass driver so you can screw them ether using the bolt hole screws fit thick screw that fits the hole and long enough so it can bit into the floor joists above and then put a bit silicon around the screw end of the hole so no air sound pressure leaks though the holes.

http://www.jblpro.com/pub/cinema/cinedsgn.pdf

 

[Bd2e]

That is excellent and I am very grateful for all the advise. I will buy the 18 and see how I go. As I said, it's not ready for the speakers yet but at that price I don't want to miss out. I can then start planning the layout and amps etc and get the room ready. Thanks again and hope you have a great Christmas and new year.


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[andyblackcat]

Well I seen them as well. and not many of them left and might have to arrange your own courier to pick them up for £20.00 or less as the seller doesn't do postal with them.

I'm guessing they were removed from Cineworld or VUE cinemas in the region.

 

[Bd2e]

Thanks for the manual, very comprehensive. A lot went over my head, I must admit, but very good and I will attempt to understand it a bit more as time goes on. I found another version which may be the one you spoke of the 1998 version which mentions the 8330 (I can't post a link as I haven't posted 10 posts but I googled "jbl cinema sound system manual 8330" and it was the 2nd link on the list).

I want to check something if I may. You say that you recommend 6 surrounds down each side. The manual suggests that the first should be approx. 2/3s from the back of the room. My room is 8.4m (F-B) and I am going to allow 0.6m for the sources, screen array and so on giving me 7.8m. 2/3 of that is 5.2m so this is my first surround speaker from the screen. It then suggests the last one should be 9-12' from the back wall so for easy calculations I will also call this 2.6m giving me 2.6m to get 6 speakers approx. 0.5m wide each into which seems a little tight as they will be on top of each other, having the last one 1.2m from the back would me 3m of speakers on 4m of wall. Have I misunderstood this or is this correct?

 

[andyblackcat]

Once you get enough posts, post clear flash pictures of the room from all angles up down side to side forwards/backwards upside-down the works so I can visualize.