What's could be causing speaker damage?

[h3ndrix]

Hello, have a couple of questions but first some background on equipment being used.

Rogue Sphinx v3 Magnum (100w @ 8ohms)
B&W 804S speakers (200w max, 90dB sensitivity)
REL B1 subwoofer (500w)
Listening position: ~2 meters away

I mostly listen to vinyl, followed by digital sources and then movies/tv.

I realize that while watching movies and such, I need to turn up my amp to get a healthy amount of dialogue in and leave plenty of room for dynamics. Let's call this, 10 o'clock on the volume knob (12 o'clock being the 'halfway' point).

When I listen to vinyl, I tend to keep it around the 9.5 to 10, but occasionally as high as 11-12 to give some records more gain. This usually yields an average SPL of 90dB from my listening position.

For digital sources, tends to be that 9 o'clock typically satisfactory.

To the questions: a few months ago I was listening to some noisy metal and noticed that at point, with a the volume up pretty high, there was a buzzing (almost burping) sound coming from my right channel. Thinking it was the source, I checked it out on digital (the original was vinyl) and it was still there. So I told myself it was intentional. Then I started to believe it was not. Fearing that something was wrong with the amp (which I know this forum is not too fond of), I swapped channels and the sound stayed with the speaker. Fearful that something was wrong with the speaker drivers, I replaced the MF in both channels (they were from 2008). Seemingly the problem went away! Both digital and vinyl copies of this same track at this same level: no more buzzing sound. A few days later, I listen to a passage from The Melvins called "Manky" and it has a bit of what I would describe as a frequency sweep.

The buzz was present again. A very nasty sound, only last a second or two. I tried to isolate if it was coming from the MF or the HF and was pretty certain it was the MF. I double checked cabling, even tightened down the binding posts on the speaker (which were only holding a jumper from MF/HF to LF). There was a little give like maybe it had gotten loosened. And then, the buzz went away! I convinced myself of some pretty silly science in that I had a faulty jumper on the binding post. It seemed believable.

Nearly a month later, I stumble on this same passage from The Melvins and decide to listen again. This time I had been enjoying the album quite loud, at almost the halfway point, and I decided to go ahead and turn it up to the halfway point. Buzz comes back. I panic, check the binding post (it worked before right?) and played the passage a few more times. This time, during on of my tests, the audio from the right channel pops and there's seemingly no level coming from the speaker MF or HF and then it comes back in a moment or two later. This was reproducible. I swapped out speaker cables for some locking bananas I have from Bluejeans thinking maybe the AQ ones I have been using are faulty. No change.

I eventually just replaced the HF with a spare I have, there's no popping now. But, I am also afraid to use the speakers. The cost in replacing the MF's wasn't cheap--and I am not even certain it was necessary. I went ahead and ordered a HF crossover thinking maybe something is amiss, but it's backordered for 2 months and I don't even know if this is the issue. I had taking a visual inspection of the crossovers just to make sure it wasn't some obvious unplugged wire or sort. I don't even know if this behavior would be indicative of a cross over problem or not.

So I lay this at all of your feet: can it be the drivers, the crossover, or maybe even the amp (somehow)? Should I be afraid to listen? Should I just turn it down? I feel like this amp/speaker combo should be capable of much louder but maybe I am crazy.

I cite the forum's notation at the top that says there are 'no trivial questions' while treading lightly into these questions...

 

[tineared]

It would be useful to have a recording or better description of the odd sound the speaker makes
It would also be useful to know what volume (in dB) the sound occurs
There are apps for your phone (I use Sound Meter) that can provide that info
I would check to see if any screws on the speaker are loose

 

[h3ndrix]

It would be useful to have a recording or better description of the odd sound the speaker makes
It would also be useful to know what volume (in dB) the sound occurs
There are apps for your phone (I use Sound Meter) that can provide that info
I would check to see if any screws on the speaker are loose

Sorry, thought I specified. It’s at 90dB even when I was right next to the speaker. I use dB Meter on my phone. A-weighting, slow response. I could record the noise but to be honest I’m afraid of breaking something. Like that pop was surely the tweeter getting fried, no?

 

[Holmz]

Most likely, either the driver got too much excursion and suffered a mechanical failure, or it is a thermal thing.
If it doesn’t stink, then it is not thermal.

The buzz was present again. A very nasty sound, only last a second or two. I tried to isolate if it was coming from the MF or the HF and was pretty certain it was the MF. I double checked cabling, even tightened down the binding posts on the speaker (which were only holding a jumper from MF/HF to LF). There was a little give like maybe it had gotten loosened. And then, the buzz went away! I convinced myself of some pretty silly science in that I had a faulty jumper on the binding post. It seemed believable

Is HF meaning “the tweeter”, and MF meaning “the midrange”?

Frequency sweeps can be hard on drivers.

But it could be the amplifier is being pushed too hard and making these sounds.
You sort of need an 0-scope to know.
But the sound disappearing from a speaker, and then coming back seems like a protection mode.

How long are the speaker cables?
If the amp is going into oscillation, then that would help to push it into thermal overload.

I dont think I would be ordering replacement parts until you know what the problem is, and what the causal mechanism is.

 

[DVDdoug]

For the volumes you like, you might just need speakers rated for higher power, or more sensitive-efficient speakers that go louder with less power.

...Usually, speakers are blown with a loud party or when a drunk or teenager is allowed to adjust the volume, or when "testing" to see how loud your system will go.

Rogue Sphinx v3 Magnum (100w @ 8ohms)
B&W 804S speakers (200w max, 90dB sensitivity)

It should be OK but speaker power ratings are "statistical" and "complicated". (And sometimes dishonest!)

A 200W speaker is supposed to be OK with 200W amplifier that's hitting 200W on musical peaks but not clipping. It's the short-term or mid-term average that burns-out speakers rather than the shorter-term peaks.

Most music has at least 6dB of dynamic contrast which means the average power is 1/4 of the peaks, and that's highly dynamically-compressed music. With most music the average is much lower. But 50W average (or 25W average from your 100W amp) MIGHT still be too much for a "200W" speaker.

More dynamic (less compressed or less "dense-intense") music that's only hitting 200W very-occasionally with a lower average is safer (and of course not as "loud".)

If you push the amplifier into clipping, the peaks are clipped-limited but the average continues to go up so the speaker can be damaged that way. And the distortion contains higher frequencies which go to the tweeter and the tweeter (and midrange) can't handle as much power as the woofer.

There is a myth that clipping from a lower-power amp is worse than an unclipped higher-power amp. The truth is that you can damage a speaker either way and more power is actually more dangerous. Plus, you are more likely to hear distortion from a lower power amp and turn it down to a safe level.

As I said, the tweeter (and midrange) can't handle as much power as the woofer. Usually that's OK because most music (and other program material) has less energy in the higher frequencies, but again it's "statistical" and variable.

And if you are diverting more power to the subwoofer, the speakers may be getting more midrange and higher frequencies than "expected" from a 100W amp (with the woofer less-stressed than expected). But at a given loudness, the subwoofer means LESS power to the main speakers so they are less stressed. And, you can crank-up the sub a bit for the "feel" of more loudness and power with less stress on the main speakers (and less stress on your ears ).

This also means that you can also burn-out a 200W speaker with constant 200W test-tones, especially the tweeter.

I realize that while watching movies and such, I need to turn up my amp to get a healthy amount of dialogue in and leave plenty of room for dynamics. Let's call this, 10 o'clock on the volume knob (12 o'clock being the 'halfway' point).

Low dialog and blasting effects are a common complaint. If you have a surround system, turning-up the center helps with dialog. Or most AVRs have a "DRC" (dynamic range compression) or "midnight mode" that evens-out the volume.

Turning-up the volume leaves LESS headroom for the dynamic peaks.

And since different sources and different programs have different volumes, the knob rotation-setting doesn't tell you anything about the actual loudness or power.

 

[h3ndrix]

Most likely, either the driver got too much excursion and suffered a mechanical failure, or it is a thermal thing.
If it doesn’t stink, then it is not thermal.



Is HF meaning “the tweeter”, and MF meaning “the midrange”?

Frequency sweeps can be hard on drivers.

But it could be the amplifier is being pushed too hard and making these sounds.
You sort of need an 0-scope to know.
But the sound disappearing from a speaker, and then coming back seems like a protection mode.

How long are the speaker cables?
If the amp is going into oscillation, then that would help to push it into thermal overload.

I dont think I would be ordering replacement parts until you know what the problem is, and what the causal mechanism is.

Speaker cables are roughly 8ft. Would the protection be built into the speakers or the amp?

 

[tineared]

So far it's difficult to determine if it is your amp or the speaker
Have you tried swapping channels from the amp to the speakers to see if it is channel/speaker dependent?
Better yet would be to use a different amp and see if the issue continues if possible
Carefully inspect the surrounds of your mid and low drivers for a tear. They can be invisible unless you apply some pressure to them with your finger
Protection is in the amp, but if it was the protection circuit the entire channel would be silent, not just some of the drivers

 

[h3ndrix]

For the volumes you like, you might just need speakers rated for higher power, or more sensitive-efficient speakers that go louder with less power.

...Usually, speakers are blown with a loud party or when a drunk or teenager is allowed to adjust the volume, or when "testing" to see how loud your system will go.


It should be OK but speaker power ratings are "statistical" and "complicated". (And sometimes dishonest!)

A 200W speaker is supposed to be OK with 200W amplifier that's hitting 200W on musical peaks but not clipping. It's the short-term or mid-term average that burns-out speakers rather than the shorter-term peaks.

Most music has at least 6dB of dynamic contrast which means the average power is 1/4 of the peaks, and that's highly dynamically-compressed music. With most music the average is much lower. But 50W average (or 25W average from your 100W amp) MIGHT still be too much for a "200W" speaker.

More dynamic (less compressed or less "dense-intense") music that's only hitting 200W very-occasionally with a lower average is safer (and of course not as "loud".)

If you push the amplifier into clipping, the peaks are clipped-limited but the average continues to go up so the speaker can be damaged that way. And the distortion contains higher frequencies which go to the tweeter and the tweeter (and midrange) can't handle as much power as the woofer.

There is a myth that clipping from a lower-power amp is worse than an unclipped higher-power amp. The truth is that you can damage a speaker either way and more power is actually more dangerous. Plus, you are more likely to hear distortion from a lower power amp and turn it down to a safe level.

As I said, the tweeter (and midrange) can't handle as much power as the woofer. Usually that's OK because most music (and other program material) has less energy in the higher frequencies, but again it's "statistical" and variable.

And if you are diverting more power to the subwoofer, the speakers may be getting more midrange and higher frequencies than "expected" from a 100W amp (with the woofer less-stressed than expected). But at a given loudness, the subwoofer means LESS power to the main speakers so they are less stressed. And, you can crank-up the sub a bit for the "feel" of more loudness and power with less stress on the main speakers (and less stress on your ears ).

This also means that you can also burn-out a 200W speaker with constant 200W test-tones, especially the tweeter.


Low dialog and blasting effects are a common complaint. If you have a surround system, turning-up the center helps with dialog. Or most AVRs have a "DRC" (dynamic range compression) or "midnight mode" that evens-out the volume.

Turning-up the volume leaves LESS headroom for the dynamic peaks.

And since different sources and different programs have different volumes, the knob rotation-setting doesn't tell you anything about the actual loudness or power.

Thanks for this. Very insightful, so perhaps I am clipping the amp. Or at least, I shouldn’t just figure that I am “safe” because of ratings. I’ve been told 90dB “isn’t that loud” but honestly I don’t need to be listening to that loud all the time time! Especially when it’s passages of frequency sweeps and noise effects, lol.

I don’t mind the “blast effects” of movies/tv. I just don’t want to fry something inadvertently.

Also, my REL subwoofer is being used in “augmentation” as in the speakers are still full-range and the REL is fed from the binding posts on the Sphinx rather than preamp out or something.

 

[Sokel]

Use your DMM and check for DC at the speaker's binding posts. (do NOT short them! )
You can also disconnect the speakers and check the resistance with the same DMM, comparing it to the "good" speaker.

As you seem ok to change drivers you can also measure the resistance of each individual one.

 

[h3ndrix]

Use your DMM and check for DC at the speaker's binding posts. (do NOT short them! )
You can also disconnect the speakers and check the resistance with the same DMM, comparing it to the "good" speaker.

As you seem ok to change drivers you can also measure the resistance of each individual one.

Could you describe exactly how to do this? Like do I check for DC at the moment the sound would be happening? What resistance level should I be looking for? I have the tweeter I suspected is bad out and available to measure but I read that resistance testing on tweeters can be bad? Or maybe that’s continuity. Either way, I feel a little helpless when it comes to measuring with my dmm, and I’m not afraid to admit it lol.

 

[Sokel]

Could you describe exactly how to do this? Like do I check for DC at the moment the sound would be happening? What resistance level should I be looking for? I have the tweeter I suspected is bad out and available to measure but I read that resistance testing on tweeters can be bad? Or maybe that’s continuity. Either way, I feel a little helpless when it comes to measuring with my dmm, and I’m not afraid to admit it lol.

Just with the gear on and no music.
Just put the DMM at DC at mV range (or auto) and check if there's any, ideally there should be none or a few mV.
You can measure it the way you said, also, when music is playing.

You can measure your tweeter just fine for resistance, as you have it at hand and compare it with the good one.
It should measure a few Ohm, something between 4 Ohm and 8 Ohm, it depends.

 

[Sokel]

Also, 90dB SPL (A) average must be close to 105dB SPL (C) for a little bass-heavy music and depending the music, peaks can be as high as 110dB-115dB SPL (Z) or more!
I don't think your speakers are made for this, neither your amp. (not healthy for ears as well for prolonged periods)

 

[h3ndrix]

Also, 90dB SPL (A) average must be close to 105dB SPL (C) for a little bass-heavy music and depending the music, peaks can be as high as 110dB-115dB SPL (Z) or more!
I don't think your speakers are made for this, neither your amp. (not healthy for ears as well for prolonged periods)

This is actually the information that I needed. I think I might have been measuring SPL wrong. Like I have been 'turning it up' because I have convinced myself that maybe I wasn't listening very loud. It certainly feels very loud. I really don't mind turning it down. I just felt like maybe I was missing out on something?

 

[Sokel]

This is actually the information that I needed. I think I might have been measuring SPL wrong. Like I have been 'turning it up' because I have convinced myself that maybe I wasn't listening very loud. It certainly feels very loud. I really don't mind turning it down. I just felt like maybe I was missing out on something?

At some time we all turn it up for fun, but it has to be brief and at the limits of our gear, no more.
I would keep average close to 75dB-80dB SPL (A) if I were you, no more than that.

 

[Holmz]

Use your DMM and check for DC at the speaker's binding posts. (do NOT short them! )
You can also disconnect the speakers and check the resistance with the same DMM, comparing it to the "good" speaker.

As you seem ok to change drivers you can also measure the resistance of each individual one.

^100%^

Speaker cables are roughly 8ft. Would the protection be built into the speakers or the amp?

Protection is built into the amp.
The effect of long cable and resonance are pretty low, but it was worth a mention.

I’d suggest if you have a DMM then set it to AC and see what the voltage is on the binding posts.
For 8 ohm speakers, then 8v is 1A, and 8v * 1A= 8W.
The peaks would be 100+

If the speakers are 4 ohm, then you double everything and get 16W and 200w+ peaks.

But at least with voltage we sort of can get to a more solid number than SPL, as we do not know if it is dB(A) or dB(C) etc.
We do know that 90dB is generally getting on the loud side, and it would be easier on the amp if the subwoofer notes were filtered off of the main speakers.

 

[h3ndrix]

Just with the gear on and no music.
Just put the DMM at DC at mV range (or auto) and check if there's any, ideally there should be none or a few mV.
You can measure it the way you said, also, when music is playing.

You can measure your tweeter just fine for resistance, as you have it at hand and compare it with the good one.
It should measure a few Ohm, something between 4 Ohm and 8 Ohm, it depends.

I measured the tweeter at around 3ohms. I still need to wrap my head around checking for DC at the speaker binding posts without shorting anything.

 

[Chrispy]

Hello, have a couple of questions but first some background on equipment being used.

Rogue Sphinx v3 Magnum (100w @ 8ohms)
B&W 804S speakers (200w max, 90dB sensitivity)
REL B1 subwoofer (500w)
Listening position: ~2 meters away

I mostly listen to vinyl, followed by digital sources and then movies/tv.

I realize that while watching movies and such, I need to turn up my amp to get a healthy amount of dialogue in and leave plenty of room for dynamics. Let's call this, 10 o'clock on the volume knob (12 o'clock being the 'halfway' point).

When I listen to vinyl, I tend to keep it around the 9.5 to 10, but occasionally as high as 11-12 to give some records more gain. This usually yields an average SPL of 90dB from my listening position.

For digital sources, tends to be that 9 o'clock typically satisfactory.

To the questions: a few months ago I was listening to some noisy metal and noticed that at point, with a the volume up pretty high, there was a buzzing (almost burping) sound coming from my right channel. Thinking it was the source, I checked it out on digital (the original was vinyl) and it was still there. So I told myself it was intentional. Then I started to believe it was not. Fearing that something was wrong with the amp (which I know this forum is not too fond of), I swapped channels and the sound stayed with the speaker. Fearful that something was wrong with the speaker drivers, I replaced the MF in both channels (they were from 2008). Seemingly the problem went away! Both digital and vinyl copies of this same track at this same level: no more buzzing sound. A few days later, I listen to a passage from The Melvins called "Manky" and it has a bit of what I would describe as a frequency sweep.

The buzz was present again. A very nasty sound, only last a second or two. I tried to isolate if it was coming from the MF or the HF and was pretty certain it was the MF. I double checked cabling, even tightened down the binding posts on the speaker (which were only holding a jumper from MF/HF to LF). There was a little give like maybe it had gotten loosened. And then, the buzz went away! I convinced myself of some pretty silly science in that I had a faulty jumper on the binding post. It seemed believable.

Nearly a month later, I stumble on this same passage from The Melvins and decide to listen again. This time I had been enjoying the album quite loud, at almost the halfway point, and I decided to go ahead and turn it up to the halfway point. Buzz comes back. I panic, check the binding post (it worked before right?) and played the passage a few more times. This time, during on of my tests, the audio from the right channel pops and there's seemingly no level coming from the speaker MF or HF and then it comes back in a moment or two later. This was reproducible. I swapped out speaker cables for some locking bananas I have from Bluejeans thinking maybe the AQ ones I have been using are faulty. No change.

I eventually just replaced the HF with a spare I have, there's no popping now. But, I am also afraid to use the speakers. The cost in replacing the MF's wasn't cheap--and I am not even certain it was necessary. I went ahead and ordered a HF crossover thinking maybe something is amiss, but it's backordered for 2 months and I don't even know if this is the issue. I had taking a visual inspection of the crossovers just to make sure it wasn't some obvious unplugged wire or sort. I don't even know if this behavior would be indicative of a cross over problem or not.

So I lay this at all of your feet: can it be the drivers, the crossover, or maybe even the amp (somehow)? Should I be afraid to listen? Should I just turn it down? I feel like this amp/speaker combo should be capable of much louder but maybe I am crazy.

I cite the forum's notation at the top that says there are 'no trivial questions' while treading lightly into these questions...

Or simply your use/expectations? Probably just overdriving the system with the gear you have is my guess (and whether those speakers are the limit or not not sure but possible)