Build a Gain Controller - next question...

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CeaSaR
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Build a Gain Controller - next question...

Post by CeaSaR » Thu Jan 12, 2012 11:44 am

Moved this to another post so as not to clog the previous one...

Will this help with this situation:

I have an observation about the audio in HD setups, specifically that which comes through the HDMI
cable. In my setup, and others I have seen, there are peripherals connected to the TV through other
inputs, ie., AV, antenna (coax), DVI/VGA audio, component video/audio, etc., and in all cases that I
have personally observed, the HDMI audio is greatly reduced as compared to the other others. It is
so reduced that when the TV's speakers are used, it can be hard to hear when doing other tasks that
involve making everyday "sounds " - cooking, cleaning, etc. Even cranked through external sound
processing it can be extremely reduced, so much so that you have to tell the perennial "gabber" to
shut their yap so you can hear what was just said. Most times the TV is cranked to 100% to hear
things clearly. By contrast, the other inputs work well at between 33% to 50%. It is so bad that I
want to add a preamp before the outboard 5.1 amp so that I don't have to crank it up all the time.
Of course it would need an auto-sense level bypass to keep it from "preamping" the other sources...

That being said, is the HDMI audio so greatly reduced because of the greater dynamic range or is it
just because the levels are kept low? This inquiring mind wants to know.

CeaSaR
Hey, what do I know?

NV100074
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Re: Build a Gain Controller - next question...

Post by NV100074 » Wed Jan 25, 2012 8:22 am

http://www.srslabs.com/store/store/come ... Product=36

http://www.tvsoundregulator.com/index2011.html

I agree, equalized audio level control of cable tv channels, on-line streaming sources, etc. is a mess. Here are two available boxes, one HDMI and one analog, that may work. I have no knowledge if they work as advertised.

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CeaSaR
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Re: Build a Gain Controller - next question...

Post by CeaSaR » Tue May 01, 2012 11:23 am

Thanks for the links. These are the same thing as the project I based this post on and
are great for normalizing/holding levels to a predetermined state. What I am experiencing
is completely different.

There is a marked difference in the audio between the different sources available to the
TV set. I have:
HDMI
AV
COMPONENT (RGB)
COMPUTER (VGA)
TV (RF)

What is hooked up:
HDMI1
AV1
AV2
TV (RF channel 3 or 4)

The HDMI is directly from the FIOS box. AV1 and 2 are the WII and PS2. The TV input is special.
This is fed from the VCR. I have a selector box fed into the VCR that allows me to select between
the AV output of the FIOS box or the DVD player. So the single TV input has 3 options available.
All in all, I have 6 sources on 4 inputs. All work as expected. Now to the crux of the problem.

When I watch regular TV through the HDMI input (so I can select between Standard def and High def)
I have to crank up the volume on the TV, usually from 67 to 100 (max) in order to make it loud enough
to hear over everyday noises. When I switch to the other inputs (AV or TV/RF), I have to turn the
volume DOWN to around 25-33 to make it a similar volume to the HDMI input. The big tell tale is when
I have the VCR set to use the FIOS box as a source. At that point I can switch between HDMI and TV
and compare directly. The audio is MUCH more loud on the TV input than the HDMI input. Hence, I have
determined that the audio on the HDMI input is somehow attenuated before it hits the analog audio chain.
It has to be that way because the same situation happens whether I use the TV's speakers or the 5.1
surround sound system.

I hope this helps clarify the original question.

CeaSaR
Hey, what do I know?

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CeaSaR
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Re: Build a Gain Controller - next question...

Post by CeaSaR » Thu Aug 09, 2012 9:11 am

Hmm, after almost 3-1/2 months, I guess no one has an answer. Perhaps when the
liquid assets start flowing more readily, I'll answer it myself. :(

CeaSaR
Hey, what do I know?

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