Question about protection circuits, movies, and speakers.

[pacsguy]

I have a problem that I hope someone can help me with.

I have a toshiba DVD player and a Sony STR-DE635 receiver. I am interested in purchasing surround speakers so I connected the DVD player to the receiver with a coaxial cable (admittedly, not a digital one) and watched 2 movies. (the Bourne Supremacy and Iron Man) the Bourne Supremacy sounded great, no issues at all. Then I played Iron man, In the first half hour, one of the scenes caused the front speakers to blow! (the scene where he is demonstrating his new bombs and there is a lot of crackling explosions). At first, I thought something was wrong with the receiver, so I did some investigation. Too coincidental that both front speakers had a problem and the center and rears did not. I had another set of speakers, I didn't care too much about, so I tried it again (hey, I'm a software guy!) Sure enough, the exact same scene caused the exact same problem. I am perplexed and need to know what is going on.

I thought the protection circuits would protect the speakers from this problem. Apparently not. The receiver never went into protection mode. Needless to say, I will not connect any speakers to this system until I find out what is going on. Actually, I am ready to replace it all, but I still need to know what is going on. I am concerned playing Iron Man (or some other movie) will cause this problem, even with new components.

The speakers are rated at 120 watts and the receiver is 80.

- anyone ever hear of this before?

- Is the receiver malfunctioning?

- Since I never used the Dolby before this, is this the problem?

- Is the DVD player bad?

- Is the movie the problem?

Anyone have any ideas on this?

I will be indebted to you all if I can get at least an explanation.

Thanks for taking the time to read this.

 

[oppman99]

The protection circuit will shut down the AVR when the current draw is too high. This does nothing to protect the speakers. You might need to give us a little more information. What speakers were you using? Do you have a sub hooked up? Did you blow a woofer or tweeter? I'm guessing here, but it sounds like you were running your front speakers full range and they are not capable of reproducing the low frequencies present in the Iron Man scene. I'm guessing you had the volume cranked and blew a woofer.

 

[highfigh]

I have a problem that I hope someone can help me with.

I have a toshiba DVD player and a Sony STR-DE635 receiver. I am interested in purchasing surround speakers so I connected the DVD player to the receiver with a coaxial cable (admittedly, not a digital one) and watched 2 movies. (the Bourne Supremacy and Iron Man) the Bourne Supremacy sounded great, no issues at all. Then I played Iron man, In the first half hour, one of the scenes caused the front speakers to blow! (the scene where he is demonstrating his new bombs and there is a lot of crackling explosions). At first, I thought something was wrong with the receiver, so I did some investigation. Too coincidental that both front speakers had a problem and the center and rears did not. I had another set of speakers, I didn't care too much about, so I tried it again (hey, I'm a software guy!) Sure enough, the exact same scene caused the exact same problem. I am perplexed and need to know what is going on.

I thought the protection circuits would protect the speakers from this problem. Apparently not. The receiver never went into protection mode. Needless to say, I will not connect any speakers to this system until I find out what is going on. Actually, I am ready to replace it all, but I still need to know what is going on. I am concerned playing Iron Man (or some other movie) will cause this problem, even with new components.

The speakers are rated at 120 watts and the receiver is 80.

- anyone ever hear of this before?

- Is the receiver malfunctioning?

- Since I never used the Dolby before this, is this the problem?

- Is the DVD player bad?

- Is the movie the problem?

Anyone have any ideas on this?

I will be indebted to you all if I can get at least an explanation.

Thanks for taking the time to read this.

Amplifier protection circuits are there to protect the amplifier, not the speakers. If you have the receiver set up so the main speakers are getting full range sound and you're playing it at high SPL, you can easily puke the speakers if they aren't capable of high excursion or power levels.

Speaker ratings aren't necessarily accurate. They often just come up with something for the sake of having something is writing. Speakers want undistorted power, not heavily clipped signal and that's what you sent to your speakers. Twice. High power isn't only used for high volume listening. It's so the amplifier can faithfully reproduce the amplified signal at whatever volume level is necessary. That said, if extremely high SPL is necessary, extreme power levels are necessary, too.

The cable you use to connect the DVD player to the receiver- there's no such thing as a 'digital' or 'analog' audio cable. That's just marketing terminology.

 

[TLS Guy]

I have a problem that I hope someone can help me with.

I have a toshiba DVD player and a Sony STR-DE635 receiver. I am interested in purchasing surround speakers so I connected the DVD player to the receiver with a coaxial cable (admittedly, not a digital one) and watched 2 movies. (the Bourne Supremacy and Iron Man) the Bourne Supremacy sounded great, no issues at all. Then I played Iron man, In the first half hour, one of the scenes caused the front speakers to blow! (the scene where he is demonstrating his new bombs and there is a lot of crackling explosions). At first, I thought something was wrong with the receiver, so I did some investigation. Too coincidental that both front speakers had a problem and the center and rears did not. I had another set of speakers, I didn't care too much about, so I tried it again (hey, I'm a software guy!) Sure enough, the exact same scene caused the exact same problem. I am perplexed and need to know what is going on.

I thought the protection circuits would protect the speakers from this problem. Apparently not. The receiver never went into protection mode. Needless to say, I will not connect any speakers to this system until I find out what is going on. Actually, I am ready to replace it all, but I still need to know what is going on. I am concerned playing Iron Man (or some other movie) will cause this problem, even with new components.

The speakers are rated at 120 watts and the receiver is 80.

- anyone ever hear of this before?

- Is the receiver malfunctioning?

- Since I never used the Dolby before this, is this the problem?

- Is the DVD player bad?

- Is the movie the problem?

Anyone have any ideas on this?

I will be indebted to you all if I can get at least an explanation.

Thanks for taking the time to read this.

What are your speakers and do have a sub?

I'm guessing you just have front speakers and no sub.

It takes an expensive robust set of speakers to handle movies without a sub.

Without a sub the low frequency effects are sent to speakers not designed for low frequency effects. Hollywood often boosts these LF effect by 20 db, which is huge and can and often does destroy cheaper subs.

There is a remote possibility that your receiver is at fault, but that would be a stretch as it would require two amp channels to produce DC offset under high power without activating protection shut down.

As far as your cable, audio RCA cables have an impedance of 50 ohm per foot (this is not the DC resistance) and digital cables 75 ohms per foot.

If you use the wrong cable as you are doing, then there is a higher bit error due to reflectance at termination. However this is usually within the range of the buffering and error correction of the device, so you notice no difference. However I use the correct cables, but that is just me.

 

[pacsguy]

Thanks for the responses.

Speakers are Gallo Micro TI.

You are correct, I haven't received the Sub and was running without. What I am hearing is that is what caused this catastrophe.

Expensive lesson for me.

So, if I have the sub connected, can I safely run movies without fear of ruining my speakers?

 

[TLS Guy]

Thanks for the responses.

Speakers are Gallo Micro TI.

You are correct, I haven't received the Sub and was running without. What I am hearing is that is what caused this catastrophe.

Expensive lesson for me.

So, if I have the sub connected, can I safely run movies without fear of ruining my speakers?

Those Gallo speakers would blow right away. When you get your sub set the speakers to small and sub yes. With those micro speakers, I would get two subs placed by each right and left front speaker and set the crossover in your receiver as high as possible.

Basically I have no time for a speaker that has "mini/micro" in any part of its name. It really helps if speakers are large.

 

[highfigh]

Thanks for the responses.

Speakers are Gallo Micro TI.

You are correct, I haven't received the Sub and was running without. What I am hearing is that is what caused this catastrophe.

Expensive lesson for me.

So, if I have the sub connected, can I safely run movies without fear of ruining my speakers?

To echo what Mark posted, you can't set the receiver to 'large speakers' when you have little ones. There are two ways to make sound- large diameter speakers that don't need tremendous excursion and small ones that need to move in and out a great distance WRT to their size. Sound is created by moving air and small cones need to move a lot in order to move anything.

If you absolutely must use small speakers, keep the bass from getting to them. If you can, use something with a larger woofer or mid-woofer.