Any video projector buffs here?

roccus

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#1
Looking for thoughts and advice......

I just got a video projector with a big screen, , I plan to connect a DVD player to it. I am going to set it up in the shop to connect to my altec speaker set up. Thing is the screen is a pull down from the ceiling screen, I plan to put it in front of my stereo rack. The projector and DVD player will be about 15 feet way from the C-1 preamp to put out to my speakers. To run an audio cable from the projector to the pre amp I am looking at a cable that would need to be 25' long. I figure 15' across the ceiling, 5' up the wall to the ceiling for the preamp, and another 5' from ceiling down wall to the projector. The audio cables I will use are the standard RCA female ends. Question is... will audio quality deteriorate going through 25' of cable? And will this cause a lag and put the movie out of sync, where you have the lips on the picture moving this way while the audio is moving in another time slot?
 

MarkWComer

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I wouldn’t expect a noticeable time lag, but that does look like an awfully long run for a line level signal. Resistance may attenuate the signal, but the lips should be in sync.
 

roccus

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I wouldn’t expect a noticeable time lag, but that does look like an awfully long run for a line level signal. Resistance may attenuate the signal, but the lips should be in sync.
So if I turn the volume up would that compensate for that?
 

mr_rye89

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#4
Projector buff here, I run a JVC D-ILA type projector with an 80" screen. I have an HDMI audio extractor to get the audio before it even gets to the projector. HDMI source -> extractor -> Schiit DAC ->amp. No lip sync problems here
 

roccus

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Projector buff here, I run a JVC D-ILA type projector with an 80" screen. I have an HDMI audio extractor to get the audio before it even gets to the projector. HDMI source -> extractor -> Schiit DAC ->amp. No lip sync problems here
Thanks... I'll try going with AV cable from DVD into projector then audio out from projector to preamp, if there are problems I will try an extractor
 

MarkWComer

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Keith if you notice a time lag, let us know and we will have you calibrated to measure the speed of light... :)
But you need to account for the speed of the electrons going through the audio cable as well, and subtract that from C.
 

MarkWComer

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So if I turn the volume up would that compensate for that?
But I question that. We’re all familiar with speaker systems of 2, 4, 8, and 16 ohms, and how they affect power amp performance. Does the same hold true for a preamp which is still an amp of sorts? What effect will an excessively long cable run have on a preamp?

Perhaps you can move the power amp close to the preamp and make a long run to the speakers- would it be a better option?
 

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#12
But I question that. We’re all familiar with speaker systems of 2, 4, 8, and 16 ohms, and how they affect power amp performance. Does the same hold true for a preamp which is still an amp of sorts? What effect will an excessively long cable run have on a preamp?

Perhaps you can move the power amp close to the preamp and make a long run to the speakers- would it be a better option?
Hmmmm...the old driveshaft question.

The preamp has an output impedance less than 50 ohms, it is driving a long cable that probably has a maximum of 10 ohms DCR, into a power amp with an input impedance of ~50K ohms...keep your power amp up close and personal to your speakers.
 

roccus

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But I question that. We’re all familiar with speaker systems of 2, 4, 8, and 16 ohms, and how they affect power amp performance. Does the same hold true for a preamp which is still an amp of sorts? What effect will an excessively long cable run have on a preamp?

Perhaps you can move the power amp close to the preamp and make a long run to the speakers- would it be a better option?
I'm not trying to run long cables from speakers to amp.... I want to run a long cable from video projector to pre amp
 

roccus

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Hmmmm...the old driveshaft question.

The preamp has an output impedance less than 50 ohms, it is driving a long cable that probably has a maximum of 10 ohms DCR, into a power amp with an input impedance of ~50K ohms...keep your power amp up close and personal to your speakers.
I'm not trying to run long cables from speakers to amp.... I want to run a long cable from video projector to pre amp
 

Gepetto

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#15
I'm not trying to run long cables from speakers to amp.... I want to run a long cable from video projector to pre amp
Yup, got that Keith. Same thing applies. You are better off with long runs from source to pre or pre to power amp than long speaker cable runs.

Was pointing out to you that your low level losses are negligible source to pre or pre to power amp...
 

roccus

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OK got it... I see they have FM transmitters to go wireless but looks like they are a bit pricey but with one of those could plug into projector then just tune the tuner in the system to that frequency... but then the sync/delay could be a problem?? The projector I have does not have blue tooth and of corse the carver C-1 doesn't either...
 

MarkWComer

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#17
OK got it... I see they have FM transmitters to go wireless but looks like they are a bit pricey but with one of those could plug into projector then just tune the tuner in the system to that frequency... but then the sync/delay could be a problem?? The projector I have does not have blue tooth and of corse the carver C-1 doesn't either...
I think you’d have more latency with the FM transmitter than with BT.
Your original plan seems to be the best option.
If you’re a Japanese kaiju fan, it’s irrelevant…
 
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