Weird Knocking Sound Coming From Front Right Speaker

[kopkiwi]

No idea what the heck the problem is, but when watching a blu-ray, specifically a blu-ray, there is a weird knocking sound coming from my front R speaker (Mission M35i).

I took a look at it and the middle woofer had sucked itself in, no idea how best to describe it, I unscrewed it and took it off, popped it back out. Figuring that would fix the problem.

Resume the blu-ray but it continued to make the weird knocking sound.

Any idea what the problem is and any idea how I can fix it?

The speakers will still be under warranty so they will be replaced if I can't fix it, but I would love to know what the issue is and if I can fix it myself.

[blu_fan]

you have it under warranty, i wouldn't touch it, if i were you. just call up the company, tell them the problem and once all the work is done with talking to them, they'll replace the woofer, or at least fix that woofer. but if they make you pay for shipping, then id fix it on my own haha.

[blu_fan]

Also, is it the dome in the middle of the woofer that's pushed in, or the outer part of the woofer that is?

[kopkiwi]

It's the entire woofer.

You know how if you push on a woofer it's spring like. Well it wasn't.

[blu_fan]

Originally Posted by kopkiwi

It's the entire woofer.

You know how if you push on a woofer it's spring like. Well it wasn't.

well, if you're talking about what i think you are, here are some forums with threads of people who has the same problem. perhaps one of these will help you:

http://www.polkaudio.com/forums/showthread.php?t=14382

http://www.gearslutz.com/board/so-mu...-do-i-fix.html

hope it helps

[kopkiwi]

The distributor is of the opinion the driver has blown.

Would be a little fcked off if that was the case. I haven't really pushed the speakers and I am under the impression they are pretty decent speakers.

Every time I push on the woofer there is a scratching/squeaking in it.

[erict]

Originally Posted by kopkiwi

The distributor is of the opinion the driver has blown.

Would be a little fcked off if that was the case. I haven't really pushed the speakers and I am under the impression they are pretty decent speakers.

Every time I push on the woofer there is a scratching/squeaking in it.

That is a blown speaker. It can happen even with high end speakers. With it being under warranty they should just send you a new driver to swap out.

[kopkiwi]

Originally Posted by erict

That is a blown speaker. It can happen even with high end speakers. With it being under warranty they should just send you a new driver to swap out.

I hate to take it into repair shop to get fixed. Should be fun carting around 35KG speaker

Is there a reason for it to happen to 2 month old speakers? Or a way to prevent it happening again?

Does it have anything to do with my speakers handling all the bass as well?

[blu_fan]

Originally Posted by kopkiwi

I hate to take it into repair shop to get fixed. Should be fun carting around 35KG speaker

Is there a reason for it to happen to 2 month old speakers? Or a way to prevent it happening again?

Does it have anything to do with my speakers handling all the bass as well?

don't play them too loud, make sure you're sending the speakers enough power since that can blow the woofer, and make sure to always keep the grill on to make sure nothing presses on it.

a reason for it happening in only 2 months could just be a defective woofer. just make sure you're sending enough power to it, otherwise, it may be how loud you're playing it. just be careful when you get the new woofer.

[kopkiwi]

Originally Posted by blu_fan

don't play them too loud, make sure you're sending the speakers enough power since that can blow the woofer, and make sure to always keep the grill on to make sure nothing presses on it.

a reason for it happening in only 2 months could just be a defective woofer. just make sure you're sending enough power to it, otherwise, it may be how loud you're playing it. just be careful when you get the new woofer.

I have them paired with a Denon 2809, so I assume that is more than enough power?

I haven't really given them a right cranking. Only really turn the volume up when listening to blu-ray, which funnily enough is the only time I hear the knocking.

[blu_fan]

Originally Posted by kopkiwi

I have them paired with a Denon 2809, so I assume that is more than enough power?

I haven't really given them a right cranking. Only really turn the volume up when listening to blu-ray, which funnily enough is the only time I hear the knocking.

the denon powers them just fine then. what volume do you usually play your blu-rays at?

it doesn't make this knocking sound when you watch to tv or listen to music?

[kopkiwi]

Originally Posted by blu_fan

the denon powers them just fine then. what volume do you usually play your blu-rays at?

it doesn't make this knocking sound when you watch to tv or listen to music?

I listen to my blu-rays on about 14. 12 at the highest.

I haven't noticed it when listening to music or normal TV. But could that just be because of the source, not as "boombastic"?

[blu_fan]

Originally Posted by kopkiwi

I listen to my blu-rays on about 14. 12 at the highest.

I haven't noticed it when listening to music or normal TV. But could that just be because of the source, not as "boombastic"?

do you mean -14 to -12?? Or 14 and 12?

i play my stuff at -10 at the loudest. you can play it loud, but don't go past 0, no matter what you do. past 0 is blasting and will definitely blow your speakers. i wouldn't recommend going any louder than -10.

[crazyBLUE]

Originally Posted by blu_fan

do you mean -14 to -12?? Or 14 and 12?

i play my stuff at -10 at the loudest. you can play it loud, but don't go past 0, no matter what you do. past 0 is blasting and will definitely blow your speakers. i wouldn't recommend going any louder than -10.

Most of the time I listen to my Blu's at -15 . I have had it at 0 & I have also had it at +10 crystal clear sound ! You should be more worried about your hearing then blowing the speakers . If the speakers are any good it would take more than most receivers have to blow them .

[kopkiwi]

Originally Posted by blu_fan

do you mean -14 to -12?? Or 14 and 12?

i play my stuff at -10 at the loudest. you can play it loud, but don't go past 0, no matter what you do. past 0 is blasting and will definitely blow your speakers. i wouldn't recommend going any louder than -10.

Yeah -14. My room is too small to warrant anything higher.

[Big Daddy]

Originally Posted by kopkiwi

Yeah -14. My room is too small to warrant anything higher.

Most probably, your driver is damaged. Try to get a replacement and do it yourself. Changing a driver is very easy and only requires a screw driver and disconnecting and connecting 2 wires.

You can clip an amplifier and damage speakers even without blasting the sound. Check inside the receiver's menu and make sure you do not have too much gain for your front speakers. Lower the gain and recalibrate your speakers. Make sure there is not too much gain added to the speakers.

Here is an example of what happens to an amplifier when you play a high quality music CD. Assume you are using a 100 watt (40 volt) amplifier and an 8 ohm speaker. The following chart is from a portion of a song (Billy Preston’s “Outa-Space”) that is fed into a computer.

http://www.rocketroberts.com/techart/powerart_a.htm

First, let’s just show a plot of the music signal. The signal was sampled at 44,100 samples per second (the rate that music CDs work at). Below is a plot that shows what the signal looks like for one channel. The vertical scale is in volts, and the horizontal scale is in samples. This “chunk” of music is just under 6 seconds long (262,144 samples):

The signal represented in this plot is that of real music, and it is just at the threshold of clipping for this 100 watt amp. One thing that can be seen is that most of the time the signal level is rather low… it is only for very short bursts that the signal reaches the threshold of clipping. These short bursts of high level signal are from bass drums! For the signal above, the amplifier would be delivering 100 watts of power for the largest peaks (those that just reach the + or – 40 volts). The RMS voltage of the signal in the plot above has a value of 6.4 volts RMS which is equivalent to 5.12 watts. We have a 100 Watt amp at the threshold of clipping, and the “average” power being delivered to the speaker is only a little above 5 watts! This is not uncommon for high fidelity music recorded on CD.

[kopkiwi]

Originally Posted by Big Daddy

Most probably, your driver is damaged. Try to get a replacement and do it yourself. Changing a driver is very easy and only requires a screw driver and disconnecting and connecting 2 wires.

You can clip an amplifier and damage speakers even without blasting the sound. Check inside the receiver's menu and make sure you do not have too much gain for your front speakers. Lower the gain and recalibrate your speakers. Make sure there is not too much gain added to the speakers.

Here is an example of what happens to an amplifier when you play a high quality music CD. Assume you are using a 100 watt (40 volt) amplifier and an 8 ohm speaker. The following chart is from a portion of a song (Billy Preston’s “Outa-Space”) that is fed into a computer.

http://www.rocketroberts.com/techart/powerart_a.htm

One question.

What is gain?

[blu_fan]

Originally Posted by kopkiwi

One question.

What is gain?

In electronics, gain is a measure of the ability of a circuit (often an amplifier) to increase the power or amplitude of a signal from the input to the output. It is usually defined as the mean ratio of the signal output of a system to the signal input of the same system. It may also be defined on a logarithmic scale, in terms of the decimal logarithm of the same ratio ("dB gain").

stole it from wikipedia

[kopkiwi]

Originally Posted by blu_fan

In electronics, gain is a measure of the ability of a circuit (often an amplifier) to increase the power or amplitude of a signal from the input to the output. It is usually defined as the mean ratio of the signal output of a system to the signal input of the same system. It may also be defined on a logarithmic scale, in terms of the decimal logarithm of the same ratio ("dB gain").

stole it from wikipedia

That helps me, not one bit.

[blu_fan]

Originally Posted by kopkiwi

That helps me, not one bit.

Gain
The gain of an amplifier is the ratio of output to input power or amplitude, and is usually measured in decibels. (When measured in decibels it is logarithmically related to the power ratio: G(dB)=10 log(Pout /(Pin)). RF amplifiers are often specified in terms of the maximum power gain obtainable, while the voltage gain of audio amplifiers and instrumentation amplifiers will be more often specified (since the amplifier's input impedance will often be much higher than the source impedance, and the load impedance higher than the amplifier's output impedance).
Example: an audio amplifier with a gain given as 20 dB will have a voltage gain of ten (but a power gain of 100 would only occur in the unlikely event the input and output impedances were identical).

there's another one...haha sorry for the other confusing one. that one's a little bit more straight forward i suppose.