Brand new Monitor 300 speaker smoking

[Mudman]

Hi, I've got a major problem here. I just bought a Yamaha network receiver, model R-N402D and 2 Monitor 300 tower speakers. All connected nicely and to start I put a usb stick with a few select tracks on it. I started learning from the user manual and got some sounds on. After about 30 minutes I was satisfied and turned the volume up to 95 %. Very loud in my small den. Excellent sound and impressive volume. After about another 25-30 glorious minutes I got the smell of smoke and using a flashlight beam, I saw fine wisps of smoke coming out of the port at the back of one of the speakers. So, switched off and disconnected everything. The shop (in Sofia, Bulgaria) says that the fault is mine for playing it too loud, meaning no repair-replacement or refund. So, given that I've been backpacking around the world for the last 30 years this is the first time I've got my hands on a decent system. I remember ( in my younger days) cranking up the volume on a variety of different systems for hours on end without any problems. I am adrift at the moment. The amp is 100w and the speakers able for 150w. As far as i am aware/ remember, that should be the end of it. The shop is talking about dodgy mp3 files and frequency clipping and playing music too loud. I need my system to play very loud some times. One hour or two for particular moment's or tracks and sometimes for parties it will need to run longer at high volume levels. I see that as a fairly basic requirement. Not what you would call unreasonable. So, my question is, is the shop right or are they giving me the runabout. Am I missing something. How do I prevent my speakers from burning.

 

[TLS Guy]

Hi, I've got a major problem here. I just bought a Yamaha network receiver, model R-N402D and 2 Monitor 300 tower speakers. All connected nicely and to start I put a usb stick with a few select tracks on it. I started learning from the user manual and got some sounds on. After about 30 minutes I was satisfied and turned the volume up to 95 %. Very loud in my small den. Excellent sound and impressive volume. After about another 25-30 glorious minutes I got the smell of smoke and using a flashlight beam, I saw fine wisps of smoke coming out of the port at the back of one of the speakers. So, switched off and disconnected everything. The shop (in Sofia, Bulgaria) says that the fault is mine for playing it too loud, meaning no repair-replacement or refund. So, given that I've been backpacking around the world for the last 30 years this is the first time I've got my hands on a decent system. I remember ( in my younger days) cranking up the volume on a variety of different systems for hours on end without any problems. I am adrift at the moment. The amp is 100w and the speakers able for 150w. As far as i am aware/ remember, that should be the end of it. The shop is talking about dodgy mp3 files and frequency clipping and playing music too loud. I need my system to play very loud some times. One hour or two for particular moment's or tracks and sometimes for parties it will need to run longer at high volume levels. I see that as a fairly basic requirement. Not what you would call unreasonable. So, my question is, is the shop right or are they giving me the runabout. Am I missing something. How do I prevent my speakers from burning.

First of all it is your fault. You did play it too loud. The speakers are rated at 150 watts, however that is very approximate, as it depends on program. It depends on the frequency response and dynamic range of the material. A lot of pop music is highly compressed and the speakers never get a break.

Also your speakers are actually four ohm. Manufacturers lie about impedance the whole time. So your amp could deliver 140 watts into that speaker. However the lion's share of the power will go to the upper mid woofer, as the lower two are just for BSC compensation.

Now think about it if you play loud compressed music, the upper woofer VC will be getting a lot of power. So the VC will get very hot indeed and smoke.

Likely you have damaged a voice coil or two. What you need to do, so that you do not ruin your receiver, is to remove each driver and test the DC resistance with a multimeter.

Any VC that is open circuit is shot. Also any VC that has a DC resistance lower than spec, has shorted turns in the VC due to overheating.

Any driver that has a DC resistance out of spec. needs replacing at your expense.

Also you need to check the crossover for any signs of burned coils and especially make sure any padding resistors are still at their correct values, and replace if they are out of spec. or discolored.

When you get the rig up and running, you need to operate it more responsibly.

 

[Replicant 7]

At a 95% of your volume level on your front display, more than likely you where driving the amp into clipping. Plus with a compressed music file on top of that surely didn't help.

 

[lovinthehd]

There is no reason for most systems to ever crank the volume dial that close to maximum....the risk is yours if you do. A more robust amp might get you a few more dB but your speakers have limits, too. How it relates to what you did with some unknown gear 30 years ago, not so much. If you truly want ear blasting volume levels, you can get gear that's more suited to it. Smoke is definitely not good, tho....

 

[Eppie]

There is no one line answer to your question as there are several factors. You can damage speakers by exceeding their power rating or by driving the amp into distortion or clipping. When the amp starts to clip the top of the analogue waveform gets chopped off and you are feeding DC current into your speakers which will overheat the voice coils and burn them out. You can damage the crossovers as well. With the volume at 95% I would also suspect that you drove the amp into clipping. 95% volume does not mean 95% max rated power. The power that gets put to the speakers depends on the type of content in the music and also on how the speaker impedance varies with frequency. Power ratings are just averages.

It has already been explained on how to go about repairing a damaged speaker, or simply pay the shop to do the repair. How do you prevent future damage? If you insist on playing at those volume levels then you will either need more power to prevent the amp from clipping or more efficient speakers that require less power to produce the same SPL levels. Unfortunately the R-N402D does not have pre-amp outputs so you can not connect an external amplifier. You would need a more powerful streamer/amp or go with a separate streamer with pre-amp outs along with a separate amp. The sensitivity of the Monitor 300 is not low at 90dB so you would need a speaker with a fairly high sensitivity to get more SPL with the same power. For example the Klipsch R-820F has a 97dB densitivity (speakers with horns tend to have a higher sensitivity).

If you get the speakers repaired, you will simply have to play the music at lower volumes or you will surely burn them out again. If you are able to upgrade the amp or speakers, there are on-line calculators like this one Peak SPL Calculator to estimate how much power you need to reach a certain volume. Use a decimal meter app on your phone to measure how loud you are playing the music to see what your target SPL in dB is.

I would also recommend some research on safe listening levels. There are tables for how long you can listen at certain dB before you start doing permanent hearing damage. 100W into those speakers in a small den would be quite loud and you probably shouldn't exceed 30 minutes per day at those levels, but you need to measure the SPL levels to know for certain.

 

[TLS Guy]

There is no one line answer to your question as there are several factors. You can damage speakers by exceeding their power rating or by driving the amp into distortion or clipping. When the amp starts to clip the top of the analogue waveform gets chopped off and you are feeding DC current into your speakers which will overheat the voice coils and burn them out. You can damage the crossovers as well. With the volume at 95% I would also suspect that you drove the amp into clipping. 95% volume does not mean 95% max rated power. The power that gets put to the speakers depends on the type of content in the music and also on how the speaker impedance varies with frequency. Power ratings are just averages.

It has already been explained on how to go about repairing a damaged speaker, or simply pay the shop to do the repair. How do you prevent future damage? If you insist on playing at those volume levels then you will either need more power to prevent the amp from clipping or more efficient speakers that require less power to produce the same SPL levels. Unfortunately the R-N402D does not have pre-amp outputs so you can not connect an external amplifier. You would need a more powerful streamer/amp or go with a separate streamer with pre-amp outs along with a separate amp. The sensitivity of the Monitor 300 is not low at 90dB so you would need a speaker with a fairly high sensitivity to get more SPL with the same power. For example the Klipsch R-820F has a 97dB densitivity (speakers with horns tend to have a higher sensitivity).

If you get the speakers repaired, you will simply have to play the music at lower volumes or you will surely burn them out again. If you are able to upgrade the amp or speakers, there are on-line calculators like this one Peak SPL Calculator to estimate how much power you need to reach a certain volume. Use a decimal meter app on your phone to measure how loud you are playing the music to see what your target SPL in dB is.

I would also recommend some research on safe listening levels. There are tables for how long you can listen at certain dB before you start doing permanent hearing damage. 100W into those speakers in a small den would be quite loud and you probably shouldn't exceed 30 minutes per day at those levels, but you need to measure the SPL levels to know for certain.

I would not recommend this guy buy a more powerful amplifier. Most speakers are smoked by too much power and not too little. This clipping explanation is bordering on fantasy. I think in fact that cause of speaker failure is rare. If clipping does become on issue, it is tweeters that will fry and not woofers. If the woofers smoked, that was too much power period.

 

[Eppie]

I would not recommend this guy buy a more powerful amplifier. Most speakers are smoked by too much power and not too little. This clipping explanation is bordering on fantasy. I think in fact that cause of speaker failure is rare. If clipping does become on issue, it is tweeters that will fry and not woofers. If the woofers smoked, that was too much power period.

While it might not be common, damage due to clipping is not fantasy. I've experienced my fair share of it while working as a repair tech and car audio installer. I was amazed at how many bone-heads thought that it was ok to play their car stereos at maximum volume. When they brought it in for diagnostics, they would crank the volume up and the music would be totally distorted and it boggled my mind that they could tolerate music that sounded so bad. A 25W amp should not be able to blow a 100W speaker but that didn't stop some people. You could smell the burned voice coils or feel the coil rub against the magnet when you moved the cone.

That's an extreme case, mind you, and I would concede that your analysis is likely more correct in this situation but the op never stated which particular component was smoking.

 

[-Jim-]

In a surprising display of unity, I'm 100% with the gang above. The OP should have been able to hear the distortion long before damage occurred (unless he just cranked it to 95% all at once, but even then distortion should be evident almost immediately). My experience it's like an early warning system.

I've been to a few house parties over the years (pre-Covid of course!) with folks packed in listening to "background" sound cranked to above Disco levels. Being a nut I always gravitated to the "system" where as soon as I heard distortion, I'd turn it down and wander off to find the Host to advise them what's going on. Some thanked me for saving their speakers, and a couple of time the host went back and cranked it back up. One called me a few days later and asked me how to fix his blown speakers.

What do they say...Oh ya...You can lead a Horse to water...