Film-Tech Forum ARCHIVE: Screening Room set-up

my profile | my password | search | faq & rules | forum home

»	Film-Tech Forum ARCHIVE » Operations » Film Handlers' Forum » Screening Room set-up (Page 3)

This topic comprises 4 pages: 1 2 3 4

Author

Topic: Screening Room set-up

Jeff Stricker
Master Film Handler

Posts: 481
From: Calumet, Mi USA
Registered: Nov 1999

posted 04-29-2000 03:25 PM

Luther, I think you will have ample gain from your solarcell with a microphone preamp stage. Here I am using a preamp with magnetic phono stage which has been modified for 'flat' response. I didn't want the RIAA phono playback EQ adding additional unknowns - thus I clipped out the equalization caps in this stage.

However, I find that significant high frequency boost is needed with this setup. Thus I'm tailoring the frequency response with an ordinary "Hi Fi system" equalizer that was rescued from a garage sale for $5.

| IP: Logged

Ben Wales
Jedi Master Film Handler

Posts: 602
From: Southampton. England
Registered: Jul 99

posted 04-29-2000 04:28 PM

I expect my screening room is one of the smaller home cinemas as I live in a ground floor flat, the living room is only 14ft x 9ft and the projection throw is about 10ft, the screen size is about 6ft wide for cinemascope and 70mm.

The projector I use is a Westrex 5000 35/70mm with a 700kw Xenon in a Orcon 1000B lamphouse.

As for sound I use a Dolby CP50 with an SRA5 Adapter for Dolby SR.

Both picture and sound looks quite good even on a screen at this size, but I have found some problems, mainly the critical picture focus and found that the Orcon 1000B even with a beam spreader you will never get a proper flat light for 70mm, the mirror is just too small for this.

I have mounted the projector base on four heavy duty castor wheels and when not in use the projector can be moved out of the living room to put the room back into normal living room mode, I do get some amazed looks from non-cinema people when they visit on occasions!.

| IP: Logged

Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 04-29-2000 05:23 PM

Erich Loepke posted <<I'll be setting up for 35mm once I get my own place (which will be pretty soon). I'll be
using a Motiograph AAA with SH7500 soundhead, an ORC 1000 lamphouse, and glorious
mono sound, all sitting on a very heavy Simplex Heavy Duty base. My lens (probably will
be used for scope) is 3.75". I've scrounged up just about everything except a pair of
rewinds, scope aperture plate, and a takeup reel belt.>>

Be carefull as the Motigraphs (aa and aaa) as well as the century c's can have problems getting short focal length lens to slide far enough back to focus

| IP: Logged

Gordon Bachlund
Jedi Master Film Handler

Posts: 696
From: Monrovia, CA, USA
Registered: Aug 1999

posted 05-03-2000 07:22 AM

For what it's worth, I placed some thoughts on "home theaters" on Sheldon Harris' web site. Visit www.film-center.com and scroll down to "Film Collecting Basics" if you are interested.

| IP: Logged

Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 05-03-2000 08:26 AM

Jeff - Luther,
If you're not setup for stereo playback then you're missing alot of the fun.
Firstly, You really need a preamp with appropriate slit loss adjustments, especially if you are going to play back stereo. Older 1.5 mil slit lenses are about as good as AM radio, perhaps just a little bit better, and I've seen them perform worse(BTW: Really good AM radio actually does sound excellent). Replacing the slit lens, even in a home situation, is a great but not so cheap thing to do. You can add at least a couple if not three full octaves of HF response to your system. And with proper slit loss eq on a proper preamp I've seen response to slightly beyond 16khz. With an LED scanner it can be even better and there is almost 0 crosstalk and much lower distortion. The only negative is that LED scanners can have higher distortion with certain old optical tracks. Also, a mic preamp does have enough gain even when feeding it with a stereo cell output.
Mark

| IP: Logged

john bishop
Film Handler

Posts: 14
From: howell,nj USA
Registered: Jun 99

posted 05-03-2000 02:31 PM

Hi folks-- what exactly is the "slit lens"? is that the metal plate in front of the exciter bulb with a slit punched-out of it? or is that the slit mask? i'm running a 1945 DeVry w/ a stereo cell but all original sound optics and was wondering if i even had a slit-lens! thanks for any answers you can provide---john

| IP: Logged

Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 05-03-2000 03:26 PM

Hi John,
Yes, The DeVry has a slit lens. I don't remember if its a standard lens or not though. We have a pair still sitting out in the dreaded shed and I'll take a look.
Basically the slit lens is an optical tube assembly that has a metal slit in between 2 sets of objectives. The filament from the exciter lamp is focused on the metal slit(the height of this slit determines ultimate high frequency response) by the first objective pair and the second pair on the film side focus the intenseley illuminated slit on the film. Pretty simple ha? Actually not......these are extremely high precision assemblys that are permanently aligned at the factory. Some slit lenses even have minature anamorphic elements to squeeze the exciter beam height!! I'll let you know later if the DeVry takes a standard lens assy or not.
Mark

| IP: Logged

Luther M. Spencer
Film Handler

Posts: 33
From: North Charleston,SC, USA
Registered: Apr 2000

posted 05-03-2000 06:19 PM

So I can optain a stereo cell and run it through a couple mic preamps...to get stereo...and If I change the slit lens it will even sound better?....MIKE

| IP: Logged

Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 05-03-2000 06:47 PM

Yep! Cleaner, more extended high end. If you decode for surround channels which you can do with any pro logic decoder you should get decent results,although a bit compressed without the proper noise reduction.
Mark

| IP: Logged

Pete Lawrence
Expert Film Handler

Posts: 192
From: Middleburg, PA
Registered: Aug 1999

posted 05-03-2000 08:29 PM

Hi John,

I'm currently using a pair of DeVry XD's, old Navy machines from the 40's. The slit lens on these is a cylinder about 1" long and 5/8" Dia., much smaller than those in the RCA type soundheads.

The biggest problem I've had is they were half full of oil when I got them. Just like every other part of these machines, inside or out! It completely killed the high frequency response. Not having any replacements, I managed to carefully take them apart and clean them. Some of the strangest optics I've ever seen. Lots of very small half-cylinder lenses, spacer rods, and aperture plates. They do come apart fairly easily and can be cleaned, but make a drawing as you go or you may never get them back together. Be very, very careful, it's not recommened for the faint of heart. However, now they are clean, the fidelity is great. I don't think that narrow slit versions are available for DeVry's.

Pete

| IP: Logged

Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 05-03-2000 09:30 PM

Sounds right Peter,
You'd have to adapt an RCA or Cinemeccanicca style lens to it. The LED route might actually be easier.
Mark

| IP: Logged

Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 05-04-2000 08:23 AM

The slit lens in a Devry is 1.5mil high and in fact barely scans the width of the track the same one was used in there 16mm machines
The FP20 slit lens will fit The others will not as there isn't enough clearance for the excitor

| IP: Logged

john bishop
Film Handler

Posts: 14
From: howell,nj USA
Registered: Jun 99

posted 05-04-2000 10:18 AM

thanks for all the help guys. gordon-- where could i get an fp20 slit lens to use on the ol' devry? and how much? thanks!! john

| IP: Logged

Gordon McLeod
Film God

Posts: 9532
From: Toronto Ontario Canada
Registered: Jun 99

posted 05-04-2000 10:43 AM

new ones are available from Boston Light and Sound
good used ones are hard to find

| IP: Logged

Richard Quesnelle
Film Handler

Posts: 67
From: Penetang, Ontario, Canada
Registered: Mar 2000

posted 05-04-2000 03:14 PM

I am so happy!! I have my first flaming thread. What a day?

| IP: Logged

All times are Central (GMT -6:00)

This topic comprises 4 pages: 1 2 3 4

Printer-friendly view of this topic

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.