The Great HDMI Cable Scam

[JorynnRace]

Just wanted to post this and spread the word for those who may not have been previously informed.

http://www.southernillinoisan....yles/life/22725785.txt

 

[BigJ]

Cables at local retailers have always been exorbitantly priced. The markup is hundreds of percentage points, if not thousands. And Monster Cable has always been exorbitantly priced compared to other brands.

For the most part, it's the price you pay for needing your cable right then and there.

 

[PurdueRy]

While the message is good, I read until the writer commented on "sending watts of power" down speaker wire. That made my EE mind explode.

But pretty much anyone on this forum will be well aware that they should not pay a huge amount for boutique HDMI cables.

 

[trmiv]

http://www.monoprice.com :thumbsup:

 

[LS21]

over christmas week Frys sold 10' HDMI cables for 5$ !!!

 

[krotchy]

Originally posted by: trmiv
http://www.monoprice.com :thumbsup:

:thumbsup:

 

[FP]

Originally posted by: PurdueRy
While the message is good, I read until the writer commented on "sending watts of power" down speaker wire. That made my EE mind explode.

But pretty much anyone on this forum will be well aware that they should not pay a huge amount for boutique HDMI cables.

PurdueRy - You have any good links that discuss the technical details of what exactly happens when a speaker is driven? I can only find simple "How a speaker works" discussions but nothing that discusses the transmission and how the resistance/impedance/capacitance of all of the components interrelate.

 

[PurdueRy]

Originally posted by: binister

Originally posted by: PurdueRy
While the message is good, I read until the writer commented on "sending watts of power" down speaker wire. That made my EE mind explode.

But pretty much anyone on this forum will be well aware that they should not pay a huge amount for boutique HDMI cables.

PurdueRy - You have any good links that discuss the technical details of what exactly happens when a speaker is driven? I can only find simple "How a speaker works" discussions but nothing that discusses the transmission and how the resistance/impedance/capacitance of all of the components interrelate.

It's really quite simple. The receiver adjusts the output voltage to represent the time varying signal which is a summation of all frequencies represented at that point in time in the audio material. Depending on which signals are played the impedance of the load changes. This could make it easier or harder to drive at certain frequencies and can demand more power at certain frequencies.

The point where a speaker is easiest to drive is dependant on a few parameters. This includes the electrical parameters of the drivers(speaker cone) itself and the mechanical parameters in the box around it. A speaker cone without a box will be easiest to drive at its natural frequency. This is the natural resonance of the RLC network which can be used to represent a speaker's behavior electrically. Putting this in a sealed box raises this frequency as a load is placed on the cone from moving. Putting this in a ported box creates two resonances, one slightly higher than the frequency the box is tuned to and one lower.

This is why low bass is often very demanding on an amp. Typically this is where the impedance approaches DC resistance and is at its lowest. This draws the most current from the amp and hence the most power.

Here is a link to a graph of a driver I measured. You can clearly see the resonance of the speaker and the rising impedance due to inductance. This is a very typical impedance plot for any speaker out of a box. This driver was 8 ohms nominal impedance. You can clearly see that this is definitely NOT what it's impedance always is.

Text

 

[spidey07]

That article is full of junk. It's not a "either works or doesn't" prospect even with HDMI. You can still get bit errors.

 

[alfa147x]

Originally posted by: krotchy

Originally posted by: trmiv
http://www.monoprice.com :thumbsup:

:thumbsup:

 

[PurdueRy]

Originally posted by: PurdueRy

Originally posted by: binister

Originally posted by: PurdueRy
While the message is good, I read until the writer commented on "sending watts of power" down speaker wire. That made my EE mind explode.

But pretty much anyone on this forum will be well aware that they should not pay a huge amount for boutique HDMI cables.

PurdueRy - You have any good links that discuss the technical details of what exactly happens when a speaker is driven? I can only find simple "How a speaker works" discussions but nothing that discusses the transmission and how the resistance/impedance/capacitance of all of the components interrelate.

It's really quite simple. The receiver adjusts the output voltage to represent the time varying signal which is a summation of all frequencies represented at that point in time in the audio material. Depending on which signals are played the impedance of the load changes. This could make it easier or harder to drive at certain frequencies and can demand more power at certain frequencies.

The point where a speaker is easiest to drive is dependant on a few parameters. This includes the electrical parameters of the drivers(speaker cone) itself and the mechanical parameters in the box around it. A speaker cone without a box will be easiest to drive at its natural frequency. This is the natural resonance of the RLC network which can be used to represent a speaker's behavior electrically. Putting this in a sealed box raises this frequency as a load is placed on the cone from moving. Putting this in a ported box creates two resonances, one slightly higher than the frequency the box is tuned to and one lower.

This is why low bass is often very demanding on an amp. Typically this is where the impedance approaches DC resistance and is at its lowest. This draws the most current from the amp and hence the most power.

Here is a link to a graph of a driver I measured. You can clearly see the resonance of the speaker and the rising impedance due to inductance. This is a very typical impedance plot for any speaker out of a box. This driver was 8 ohms nominal impedance. You can clearly see that this is definitely NOT what it's impedance always is.

Text

Since I mentioned this and just made a measurement of it...here is the same driver shown in the previous attachment now in a vented enclosure instead of free air:

Text

The inductive rise is no longer present due to impedance compensation circuitry in parallel with the woofer. This has nothing to do with the vented enclosure.

 

[Rubycon]

That being said, there is one two things you do need to be aware of when purchasing an HDMI cable. First, you have to get the right length. If the cable isn't long enough, it won't reach to the HDTV.

Damn that is great. I would never have known that! :|

:laugh:

 

[PurdueRy]

Originally posted by: Rubycon

That being said, there is one two things you do need to be aware of when purchasing an HDMI cable. First, you have to get the right length. If the cable isn't long enough, it won't reach to the HDTV.

Damn that is great. I would never have known that! :|

:laugh:

I expect some analysis to back up that bold statement.