HDMI Cables, Speaker Impedance, HDMI Splitters

What's in a Number?
Will Blu-ray play through an HDMI 1.3 cable? I replaced a standard DVD player with a BD player and 
lost the sound. The cable is 1.3. Does that make a difference?
 


Bruce K. Dormanen

An HDMI cable rated for version 1.3 is perfectly fine for Blu-ray, even 3D Blu-ray, as long as it can accommodate a data bandwidth of 10.2Gbps, which is assured if it's Simplay-certified. Without more information, I can't troubleshoot your problem. What equipment are you using now? What were you using before? Were you using HDMI with the DVD player? If so, and you heard audio then, the Blu-ray player's HDMI output could be faulty.

Here are a few things to try. First, replace the HDMI cable with a different one; if you hear audio, the original cable is faulty. If that doesn't work, connect the HDMI cable to a different HDMI input on the receiver; if you hear audio, the first HDMI input is probably faulty. If that doesn't work, connect the Blu-ray player's optical or coax digital-audio output to the receiver and select the Dolby Digital audio track on a disc; if you hear audio, the player's HDMI output could be faulty.

Heavy Load
I have a pair of Thiel CS 1.2 speakers that have a nominal impedance rating of 4Ω, but my Onkyo TX-SR507 receiver is spec'd at 75 watts per channel into 8Ω or 100Wpc into 6Ω. The sound I get when watching movies seems to be adequate, but when I listen to music, it doesn't seem to be the quality I would expect from high-end Thiel speakers. I haven't run into any overheating issues with the receiver up to now. Will this setup cause any long-term damage to the speakers? And when I have the budget, would you recommend upgrading to a higher-end receiver or simply adding a quality power amp to my current setup?

Kurt Mannhardt

I suspect the Thiels' impedance is too low for the receiver, which is a pretty low-end model for these speakers. The speakers are trying to draw more power from the receiver's amps than they are comfortable providing, and the sound is compromised as a result. Also, the tweeters are susceptible to damage under these conditions because of high-frequency, high-power distortion from the amp.

Either solution you suggest would work, as long as the new receiver or power amp is rated to drive 4Ω speakers. I would definitely upgrade as soon as you can afford to.

Two for One
Are HDMI splitters any good? My Harman Kardon AVR 247 A/V receiver passes 1080p with lots of sparklies. I want to split the HDMI from an HTPC and send the video directly to the Panasonic TC-P54G20 plasma and the audio to the receiver.

Mark Spivey

I want to take the HD signal from my Dish 612 HD DVR and send it to two HD monitors. The cable run from the Dish receiver to each of the monitors is less than 8 feet. I am unclear on whether a simple HDMI "Y" adaptor will work or if I need a specific type of powered device.

Jeffrey Ellis

Mark, have you tried connecting the HTPC directly to the TV to make sure the problem is in the AVR? If not, I recommend doing that before investing in an HDMI splitter. Also, how long is the HDMI cable from the HTPC to the AVR and from the AVR to the TV? If either one is longer than 15 or 20 feet, that could be the problem. If the AVR really is the problem, using an HDMI splitter as you describe might be a good solution.

Jeffrey, there is no such thing as a passive HDMI "Y" adaptor as there is for analog audio, because HDMI carries a complex datastream with bidirectional handshaking, which requires sophisticated circuits to handle correctly. There are plenty of good HDMI splitters on the market from companies such as Accell, DVIGear, and Key Digital. (Gefen also makes them, but I've had some problems with its splitters.) We use an Accell 4-in/8-out switcher/splitter in the studio with no problems at all.

If you have a home-theater question, please send it to scott.wilkinson@sorc.com.

COMMENTS
Juan Sebastián Valencia's picture

Mr. Wilkinson.Yours sincerelyI've been a reader of your articles and I really like.I take the issue to ask something related to analog and digital coaxial cables.I have a question regarding the possibility of using analog video cable (yellow RCA) for use in the digital coaxial output. These cables provide a 75 ohm impedance similar to digital cable? this is true? These will offer similar performance to a digital coaxial cable?I have several analog video cables without using, and let me know if I can use for this applicationThank you very much for your comments, and be aware of their recommendations.Sincerely,Juan Sebastian ValenciaArt restorer and conservatorBogota Colombia

Matt Gosselin's picture

I have a question also regarding digital audio. I was reading your gift guide and I saw you recommended Channel D's Pure Music. I've been thinking about getting an external DAC and using my computer's mini-TOSlink out into it. Will Pure Music benefit the digital out, which I'm told is a little lacklustre, or will I be wasting my money?

Erik C's picture

Perhaps Bruce has to select HDMI in the audio portion of the setup menu on the blu-ray player. It may not be automatic.

Doug Peterson's picture

Scott,Regarding the above of lower impedance speakers than the amp is rated for, would it not be the case that at low to moderate volumes the current draw would be acceptable but only at peak volumes that the problems with excess current draw show up? How does high frequency distortion get generated at normal listening levels, or is it the case that the amp clips at lower powers into that lower resistance?--a fan

Adam 's picture

@Bruce.If you connect the blu ray to a receiver with both HDMI and digital coax/optical for audio, and then you get sound, it could mean two possible outcomes. Either A. your player's HDMI port is bad or B. Your receiver is not a fully HDMI equipped, like some of the lower end models over the over the last couple years.Just a thought.

Scott Wilkinson's picture

Juan, as far as I've been able to determine, composite-video and coax digital-audio cables are both intended for 75 ohm connections, so they should be interchangeable, and the performance should be comparable.Matt, I don't know the Pure Music DAC specifically, but I suspect that using a good external DAC could improve the performance of your computer's audio. The computer's DAC is probably not the best quality, and it sits in an electrically noisy environment (the computer).Erik, good suggestion, though I don't think I've ever come across a player that didn't automatically output audio via HDMI if that's the connection being used.

Scott Wilkinson's picture

Doug, you're right that low listening levels are less likely to distort when feeding low-impedance speakers, but many people fine low levels unacceptable. You ask if high-frequency distortion occurs at "normal" listening levels, but "normal" for many people is quite loud. It's always best to match the amp's capabilities to the speaker's impedance.Adam, good suggestion. I don't recall ever connecting both HDMI and optical/coax, and I don't know if they are always active simultaneously. The only receiver I know of that does not pass audio via HDMI is the first HDMI-equipped Rotel AVR.

Jarod's picture

On my old setup a few years ago a had a Onkyo reciever that was from an Onkyo HTIB. None of its hdmi inputs, that were codec 1.1 I believe, would pass thru auido. I used a digital coaxial cable from my DirectTV DVR and an optical cable from my Sony BD player.

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