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Author Topic: One for the Audiophiles
Gary Baker
Film Handler

Posts: 34
From: Glasgow, Scotland
Registered: Apr 2017

- posted April 30, 2017 04:20 PM      Profile for Gary Baker   Email Gary Baker   Send New Private Message       Edit/Delete Post 
First of all, sorry that my next post's another newbie request for advice but after much searching I couldn't find info related to my issue.

Only fairly recently acquired a sound projector and been making do with the in-built speaker on my Eumig S810D. After trawling through some old posts here I realised I could buy an adapter that would allow me to connect the 'out' socket to the RCA ports on my modern Yamaha AV receiver...and Hey Presto! Front audio from the speakers on my projection wall which I use as part of my 7.1 digital system. Don't even get any of the 'hum' I've heard others associate with this projector and method. The only minor issue is the analog signal is favouring the front left speaker (with some faint volume coming from the right.) Does anyone know if it's possible to spread the sound more evenly over the two speakers? Or even just direct it to the centre channel? I'm pleased as punch that I've got this working at all but you know how it is...always looking to tinker and tweak whatever improvements might be possible.

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

- posted April 30, 2017 04:37 PM      Profile for Andrew Woodcock         Edit/Delete Post 
Be extremely careful Gary connecting our old vintage projectors directly through to a modern home cinema digital system.
It is extremely easy to completely ruin certain components within your receiver and loudspeaker cabinets.
They are made to handle today's squeaky clean digital input sources and generally can often express a complete dissatisfaction with anything beyond this.

I'd advise you to at least fit a modern mixer in between the two from your projection table. Better still is to use a separate amplifier and speaker system of similar vintage for just your cine gear or old analogue sources.

Many modern mixing desks offer effects that will very easily allow you to create a pseudo two channel stereo clean input signal into your amplifier from just a single mono input from your projector.

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"C'mon Baggy..Get with the beat"

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Will Trenfield
Jedi Master Film Handler

Posts: 506
From: Shrewsbury, Shropshire, UK
Registered: Mar 2016

- posted April 30, 2017 05:38 PM      Profile for Will Trenfield   Email Will Trenfield   Send New Private Message       Edit/Delete Post 
Sound advice from Andrew there. The Eumig S810D is over 40 years old. Best not to connect its output directly to today's hi-tech equipment. I connect the output from my S712D to a 25 year old, or so, music centre which is still going strong.

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

- posted April 30, 2017 06:12 PM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
The thing you run into with an 800 series Eumig is the output impedance of the line level signal is 50,000 ohms and most amplifiers are 10,000 Ohms looking in. When you put two in parallel you get 5,000 Ohms. When you connect them to the Eumig output you are now seeing something like 10% of the original signal level.

Then again there is the hum and the grounding problems these often have.

My Eumig and my Amp never played nicely together until I put a mixer in-between:

Adding an Audio Mixer

(It's most of the way to the bottom: just to save time!)

These panels aren't very expensive and they make the business end of the system much more flexible. I can have multiple projectors and other audio sources too. I recently added in a video player and projector ad it hooked right up.

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All I ask is a wide screen and a projector to light her by...

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Paul Browning
Phenomenal Film Handler

Posts: 1006
From: West Midlands United Kingdom
Registered: Aug 2011

- posted April 30, 2017 06:16 PM      Profile for Paul Browning   Email Paul Browning   Send New Private Message       Edit/Delete Post 
I don't know the output or impedance of the eumig you have, but you could connect two speakers together as long as they are the correct resistance, two 8 ohm speakers connected in parallel would be 4 ohms, as long as they are the same power rating you would get sound from both. It may say somewhere on the back of the projector or if you have the manual it will probably be in there.

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

- posted April 30, 2017 06:22 PM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
The output I'm talking about is the DIN line level connection at the front lower corner of the machine (below the framing knob). This is what is best used for an amplifier input.

The nice thing about going this way is you can clean up the signal externally a lot easier.

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All I ask is a wide screen and a projector to light her by...

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Winbert Hutahaean
Film God

Posts: 5468
From: Nouméa, New Caledonia
Registered: Jun 2003

- posted April 30, 2017 06:48 PM      Profile for Winbert Hutahaean     Send New Private Message       Edit/Delete Post 
You guys forgot with his crucial question but more into some tech explanation [Smile]

quote:
The only minor issue is the analog signal is favouring the front left speaker (with some faint volume coming from the right.)
If your film and/or projector is mono then there is spill out from your left channel.

If it is stereo, you must understand that the stereo 2 channel in film prints is recorded on two different bandwidth due to different size of the magnetic track.

If you see the one close to the sprocket has narrower track than the one one the right (main channel).

8mm film is not meant for stereo sound. The narrower track is meant as the balance strip to make it even when film getting through the path. So film will have the balane focus on all frames.

Cheers,

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Winbert

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

- posted April 30, 2017 07:36 PM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
I think he has to turn the volume way up because of the signal reduction I was talking about.

When you do this things like hum and crosstalk and hiss become more noticeable.

-you magnify anything enough, all the flaws come up too!

The joy of using the mixer is the monaural inputs have a knob that lets you put it all in the left channel, all in the right channel, or divide it up between them any way you'd like.

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All I ask is a wide screen and a projector to light her by...

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Gary Baker
Film Handler

Posts: 34
From: Glasgow, Scotland
Registered: Apr 2017

- posted May 01, 2017 10:11 AM      Profile for Gary Baker   Email Gary Baker   Send New Private Message       Edit/Delete Post 
Thanks all. I certainly wouldn't want to mess up my amp in any way so will take the advice on not connecting directly. Will look into a mixer as it's the kind of thing I might get some other uses out of. Cheery-ta!

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

- posted May 01, 2017 10:27 AM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
They are a pretty minor expense. Mine is two monaural channels and two stereo channels with a simple equalizer each and per-channel volume controls. There are also one or two very simple inputs and outputs added in which are basically just on/off.

This ran me $65. There are several simpler ones that are cheaper.

-on the other hand if you are willing to lay out the cash you can get ones with enough knobs and sliders to frighten a Rocket Scientist!

If "used" is your thing, they are on E-bay cheap as dirt, and even cheaper than potting soil.

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All I ask is a wide screen and a projector to light her by...

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

- posted May 01, 2017 10:52 AM      Profile for Andrew Woodcock         Edit/Delete Post 
I can recommend a Numark CM 200FX for this purpose. It has a nice fx section to give you good spacial sound to your mono tracks, even in a soft furnished lounge area.
Has a basic equalizer built in also to filter out the nasties.

For anything more precise, id recommend you add in a rack mount Behringer EQ.
Both excellent value for money units.

Keep your gain low until you gain experience with any mixer settings and dont encroach the red led areas to keep the amp signal the purist it can be.

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"C'mon Baggy..Get with the beat"

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

- posted May 01, 2017 11:15 AM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
-and we have to be fair here too: these aren't exactly plug and play. The "play" part is pretty easy, it's the "plug" that makes life interesting.

To get my 800 series Eumig to play nice with my Behringer mixer I needed a cable that may not exist anywhere else on this planet (at that rate the other planets aren't looking good either...): DIN monaural male to a balanced 1/4" TRS plug. (These are usually called stereo phono plugs but in this case they are used for one monaural channel.).

I have one because I bought the pieces and soldered them together. If you are of the soldering persuasion I'd be happy to describe it for you.

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All I ask is a wide screen and a projector to light her by...

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Martin Davey
Film Handler

Posts: 94
From: Southampton UK
Registered: Dec 2011

- posted May 01, 2017 11:30 AM      Profile for Martin Davey   Author's Homepage   Email Martin Davey   Send New Private Message       Edit/Delete Post 
A sneeky workaround suggestion! With my set up I use a 3.5mm input jack on the front of the Yamaha (AV) amp. Inserting the jack fully would present you with the normal L or R choice for mono, depending on the connections between the projector and amp. However I found by accident that if the jack is slightly pulled out from the amp that the signal then comes from both the L and R. If the 'pro logic' circuit is activated then the sound is placed in to the C channel and the mono track sits perfectly with the picture. Obviously experiment with this at low levels!

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

- posted May 01, 2017 11:47 AM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
That makes sense!

Fully inserted, the tip is left, the ring is right and the sleeve is ground. When a monaural plug is inserted in a stereo jack, the tip contacts the left contact, but the sleeve contacts both the right contact and ground contact, so right is grounded and that channel is dead.

I think what you've done is by partially pulling the plug out, now the tip is touching BOTH left and right and ground is still grounded.

It aint the way the ship was meant to sail, but it's at least understandable.

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All I ask is a wide screen and a projector to light her by...

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Martin Davey
Film Handler

Posts: 94
From: Southampton UK
Registered: Dec 2011

- posted May 01, 2017 11:58 AM      Profile for Martin Davey   Author's Homepage   Email Martin Davey   Send New Private Message       Edit/Delete Post 
lol, thanks for the clarification Steve!

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Paul Browning
Phenomenal Film Handler

Posts: 1006
From: West Midlands United Kingdom
Registered: Aug 2011

- posted May 01, 2017 12:12 PM      Profile for Paul Browning   Email Paul Browning   Send New Private Message       Edit/Delete Post 
Steve the plugs you talk of do exist, I use them every week with virtual dj, into a mixer, left and right channel connected together for deck one, same for deck two, but one phono connection in, two phono's out, into decks one and two. Works perfectly, but you only get mono sound out.

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

- posted May 01, 2017 12:59 PM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
Oh well, I enjoy putting this stuff together at any rate.

This may be a regional thing: there is DIN standard equipment over here, but it's usually pretty old. As a matter of fact, a lot of the time when I order DIN connectors they start out across the Pond. I did a pretty decent order from Maplins about a decade back. I'm still using it up.

It wasn't always this way. Back in my teenage years I'm pretty sure I could buy DIN connectors at Radio Shack. I didn't KNOW that's what they were: just another of many things I learned too late!

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All I ask is a wide screen and a projector to light her by...

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Andrew Woodcock
Film God

Posts: 7477
From: Manchester Uk
Registered: Aug 2012

- posted May 01, 2017 02:23 PM      Profile for Andrew Woodcock         Edit/Delete Post 
The reason why vintage audio equipment works far better with our 70's cine equipment is simply because it is better matched.
Today's loudspeaker arrangements have a far higher frequency range as well as generally having far greater sensitivity for quality audio gear.
This is actually a detrimental aspect when it comes to what you actually want to hear from our projectors soundtracks and magnetic head reproduction. Even more so if using optical sound films.

The speakers of the same era and better still, those purposefully made for our machines, do by far a better job of letting us all hear only what we all want to hear and much much less of the things we don't!

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"C'mon Baggy..Get with the beat"

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Will Trenfield
Jedi Master Film Handler

Posts: 506
From: Shrewsbury, Shropshire, UK
Registered: Mar 2016

- posted May 01, 2017 06:08 PM      Profile for Will Trenfield   Email Will Trenfield   Send New Private Message       Edit/Delete Post 
Very true, Andrew. As speakers age, their performance can increase but this is cancelled out by the frequency range of our own hearing decreasing with age!

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Gary Baker
Film Handler

Posts: 34
From: Glasgow, Scotland
Registered: Apr 2017

- posted May 02, 2017 10:30 AM      Profile for Gary Baker   Email Gary Baker   Send New Private Message       Edit/Delete Post 
A true wealth of knowledge and tips. Thanks Guys!

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Gary Baker
Film Handler

Posts: 34
From: Glasgow, Scotland
Registered: Apr 2017

- posted May 14, 2017 06:05 AM      Profile for Gary Baker   Email Gary Baker   Send New Private Message       Edit/Delete Post 
Okay, so I invested in a basic but bitchin' Behringer mixer and now my sound is nicely balanced across the front speakers. I even found the DIN monaural male to stereo phone jack that Steve described. Sorted!

I can now enjoy my cine film and perhaps avoid blowing up my shiny new amp. Also as I'm projecting onto the same wall I use for my HD cinema I get the best of both worlds.

Thanks again for the sound advice.

Pun optional [Smile]

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

- posted May 14, 2017 08:16 AM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
Hi Gary,

We are glad we can help. Personally, I enjoy fixing problems this way: I don't even need to put my tools away afterwards!

If you can, please post a link to the cable you bought (even just the part number). Other people who need to make the same connection will find it useful.

Thanks!

I'm guessing your mixer is something like Xenyx 502.

What I like about these is the connectivity they allow. For example, just for laughs I grabbed a couple of cables and adapters recently and plugged my IPhone into mine recently and played music through my stereo: very easy and it worked fine. (-we all get laughs in our own way!) Recently my son needed to listen to a talk from a website and write a report for school. Once again: a couple of cables and adapters and my laptop was playing through my stereo.

We don't actually use these the way they are intended. We don't often mix multiple channels, but select one and control its volume. Maybe we should call them "choosers" and not "mixers"!

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All I ask is a wide screen and a projector to light her by...

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Gary Baker
Film Handler

Posts: 34
From: Glasgow, Scotland
Registered: Apr 2017

- posted May 14, 2017 12:50 PM      Profile for Gary Baker   Email Gary Baker   Send New Private Message       Edit/Delete Post 
You're spot on about the Xenyx502; that's precisely the unit I went for.

I also enjoy playing around with this stuff as I find it very therapeutic (when I'm not tearing my hair out). Presumably if I were to get a stereo capable projector this bad boy could handle it no problem. The tinkering possibilities are endless.

I got the cable from Amazon UK. Here's the link:

[URL=https://www.amazon.co.uk/kenable-3-5mm-Stereo-Audio-Cable/dp/B003OSNVC4/ref=sr_1_1?ie=UTF8&qid=1494787355&sr=8-1&keywords=5+Pin+Din+MIDI+Plug+To+3.5mm+Jack+Stereo+Plug+Audio+C able]Amazon[/URL]

[ May 14, 2017, 02:00 PM: Message edited by: Gary Baker ]

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Steve Klare
Film Guy

Posts: 7016
From: Long Island, NY, USA
Registered: Jun 2003

- posted May 15, 2017 09:17 AM      Profile for Steve Klare   Email Steve Klare   Send New Private Message       Edit/Delete Post 
Gary,

Your cable is subtly different from what I have. Just for the sake of discussion here's the difference:

Yours:
Pin 2: Sleeve
Pin 3: Ring
Pin 5: Tip

Mine:
Pin 2: Ring
Pin 3: Tip
Pin 5: (not connected)

What you have is an unbalanced stereo DIN to 1/8" phono plug.

Mine is a balanced monaural DIN to 1/4" phono plug. (no adapter)

What difference does it make? In your case none at all. In the setup you have right now it is performing well and for the gain in performance you've made it sounds like £2.18 (with free shipping!) well spent.

There may come a day when you connect in some other piece of grounded equipment (another projector, for example) and all of a sudden you will notice hum in your speakers. This is because you've connected two pieces of grounded equipment and as a result of the difference in the qualities of the two grounds you are now running current back and forth in the grounding line and the resulting voltage is getting added into your audio signal. It shows up in your speakers as hum. (Eumig 800s are notorious for this.)

The balanced connection isolates the different grounds and puts a stop to this.

Carry on Projecting! Enjoy yourself, but if you ever run into this problem, just remember this thread.

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All I ask is a wide screen and a projector to light her by...

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Gary Baker
Film Handler

Posts: 34
From: Glasgow, Scotland
Registered: Apr 2017

- posted May 16, 2017 07:29 AM      Profile for Gary Baker   Email Gary Baker   Send New Private Message       Edit/Delete Post 
Okay, so NOW I hear the hum!

I don't know why I didn't before. It's possible I was just so delighted to successfully redirect the sound at all that I was deaf to the problem. Anyway, Steve, I've re-read your 'Adding a Mixer' thread and despite not being sure I follow your explanation of the issue, I'd sure like to take you up on your kind offer to describe your soldering work-around. I've not soldered much more than the odd resistor to LED lights for model display purposes, but I reckon I'm up to it.

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