Genelec 8050a woofer popping

[TomLynas]

I've got two Genelec 8050as. They're second hand and have been repaired a few times.

When I got them, one of the tweeters crackled, so we sent them to be repaired and when I got them back is when this issue first started. When the speaker is turned up decently loud, (to when it clips or right before it clips) and it plays a kick, there is a stranger popping, cracking or slapping sound. It seems completely fine until the issue appears, no increase in distortion or anything like that, until I turn it up enough that the popping starts. My theory is that one or two of the screws howling the woofer in place is loose, causing the woofer to repeatedly hit the front of the speaker when there is large, almost instantaneous exertion, which you get from a kick but I'm not sure this is right.

Some people might be wondering if this is normal when the speakers are pushed to the point of clipping but it is definitely not. All the clipping should do is dial back the volume of whatever is too loud for the amp or cone to produce, the should not be any noticeable popping sound.

Here's some videos of it happening, taken last year. (I can't workout how or even if I can upload videos here so I've put them on YouTube instead.)

I sent them back to the repair shop after this again and they somehow managed to send them back completely broken, internals completely loose inside the speakers. So, I had to send them back AGAIN and this time they finally seemed okay. But over a year later, (now) the same issue has started happening again.

This is a video of it happening last week.

I found a video of something similar on reddit if that helps anyone narrow it down.

https://www.reddit.com/r/diyaudio/comments/1svavym/dynaudio_contour_1_mk2_woofer_making_popping

As you can hopefully hear, it's making the same sound as it did last year. Would appreciate some ideas.

 

[levimax]

To me it sounds like the woofer is "bottoming out". Are you using EQ in the bass? I have some Neuman monitors (Not Genelec), and I have noticed that if I EQ the bass and play loud bass heavy music they can bottom out, even though they are supposed to have "protection circuitry" to prevent this. If this is the issue then the solution is either changing the EQ, turning down the volume, or getting some sub(s). I recommend some BIG subs for the music you are trying to play .

 

[kharan]

That red light? That's the limiter in action. Avoid the red light.

 

[YouDontHaveEnoughBass]

gonna have to turn it down till the red light stops coming on, and if thats not loud enough grab a subwoofer to crossover to

 

[TomLynas]

My other Genelec doesn’t have this issue though. There shouldn’t be a popping sound even when it clips.

The whole point of a limiter is so something like this doesn’t happen, which could be the reason, the limiter isn’t working properly. But if you watch some of the earlier videos, the popping can happen before the speaker clips.

I’ve just got a 7070a anyway so it’s fine, I’ve eqed the bass below 85hz out before and the popping goes away but this still shouldn’t be an issue on such high end monitors and I don’t think it is a common problem with Genelecs.

There was no eq on them either so that’s not it.

 

[TomLynas]

To me it sounds like the woofer is "bottoming out". Are you using EQ in the bass? I have some Neuman monitors (Not Genelec), and I have noticed that if I EQ the bass and play loud bass heavy music they can bottom out, even though they are supposed to have "protection circuitry" to prevent this. If this is the issue then the solution is either changing the EQ, turning down the volume, or getting some sub(s). I recommend some BIG subs for the music you are trying to play .

I’ve just got a 7070a (for £700!), but either way this is still an issue, if something is wrong with the internals I would like to know what it is and get it fixed. These sort of things tend to get worse otherwise.

It is the same speaker with the same issue, and the other one doesn’t do the same thing which is why I know this isn’t ’normal behaviour’. Usually when the red light comes on it just cuts some of the bass out, no weird sounds involved.

 

[mlsstl]

Just curious how loud you're listening when the pop occurs. Have you measured with a sound level meter? Have you run a bass frequency sweep to see if a particular frequency is involved?

 

[Keith Flanker]

If cutting everything below 85Hz makes the popping disappear, that’s the classic signature of excursion-limited bottoming rather than a limiter fault — the limiter reacts to temperature/current, but a short kick transient can exceed the woofer’s mechanical travel before it responds. Since it’s the same unit that had repairs, I’d suspect the driver itself: check the voice-coil former or spider alignment, and try a single 40–60Hz tone at rising level — if the noise appears only on loud low-frequency bursts, it’s mechanical (former hitting the backplate), not the amp. It’s also worth pressing gently around the surround and checking the woofer screws while playing the tone, to rule out an air leak or loose driver. Given the repair history, a driver rebuild is more likely the fix than electronics.

 

[b73i57dc3f]

Amir observed the same in his review:

Right when I wanted to quit and give the 8050B my highest honors, bass came and sadly at high volumes, it becomes ugly. The woofer makes this "brrrrrr" sound, first faintly and then strongly as you push it.

As such, I think the only real solution here is getting different speakers that don't have this problem. More modern speakers with DSP might have more elaborate limiters that perform better.

even though they are supposed to have "protection circuitry" to prevent this

The primary purpose of the protection circuitry is to prevent driver failure, preventing audible distortion when overdriven is a secondary concern. Genelec writes:

The protection circuitry prevents driver failures by detecting signal levels, and in case of sudden peaks or constantly too high levels, taking the signal level down automatically. Of course this feature does not affect the sound quality in any way when working within the specifications of the loudspeaker, but only prevents inadequate input signals from breaking the loudspeaker.

As I read it, they don't make any promises about not affecting sound quality with "inadequate input signals".

 

[kemmler3D]

Yeah based on the video I think you're physically maxing out the woofer in some way. It's not clipping but I think the woofer is overloaded, possibly bottoming out. Just don't play it that loud. These are not outdoor / party speakers, they're designed to be used sitting indoors maybe 6 feet away, 10 at most? You can get PAs that will go much louder for the same money for loud listening.

You can also DIY much louder speakers for similar / less money.

 

[TomLynas]

If cutting everything below 85Hz makes the popping disappear, that’s the classic signature of excursion-limited bottoming rather than a limiter fault — the limiter reacts to temperature/current, but a short kick transient can exceed the woofer’s mechanical travel before it responds. Since it’s the same unit that had repairs, I’d suspect the driver itself: check the voice-coil former or spider alignment, and try a single 40–60Hz tone at rising level — if the noise appears only on loud low-frequency bursts, it’s mechanical (former hitting the backplate), not the amp. It’s also worth pressing gently around the surround and checking the woofer screws while playing the tone, to rule out an air leak or loose driver. Given the repair history, a driver rebuild is more likely the fix than electronics.

I think the biggest clue is that it doesn’t happen if I play a LF tone loudly. If I do that the speaker clips and dials back the volume, its specifically on transients that this happens.

I know you just said it sounds mechanical but do you think it could be that the protection circuit doesn’t have time to react to the transient? Or is it likely unrelated to the protection circuitry and is over exertion of the driver causing something you mentioned to physically hit something inside the speaker?

I’ve basically got two options, I can get ask for it to be repaired again for free as it’s the same issue as before which means it falls under the consumer rights act, but the company might just offer a refund instead. Or I can take it into my uni, I study Acoustical and Audio Engineering, and see if they can help me open it up and fix it, therefore voiding any warranty that I’ve got on it.

The second time I had them repaired this is how they came back, so I don’t have much confidence in the company.

 

[kharan]

I think the biggest clue is that it doesn’t happen if I play a LF tone loudly. If I do that the speaker clips and dials back the volume, its specifically on transients that this happens.

I know you just said it sounds mechanical but do you think it could be that the protection circuit doesn’t have time to react to the transient? Or is it likely unrelated to the protection circuitry and is over exertion of the driver causing something you mentioned to physically hit something inside the speaker?

I’ve basically got two options, I can get ask for it to be repaired again for free as it’s the same issue as before which means it falls under the consumer rights act, but the company might just offer a refund instead. Or I can take it into my uni, I study Acoustical and Audio Engineering, and see if they can help me open it up and fix it, therefore voiding any warranty that I’ve got on it.

The second time I had them repaired this is how they came back, so I don’t have much confidence in the company.

I saw the red light on many times in the videos you've posted.

The red light is a warning sign that you should turn down the volume and that the over excursion protection is active. The over excursion protection isn't perfect. If you have used the speaker for a significant duration for which it needed over excursion protection, it wouldn't be surprising that the woofer was damaged and that it now has issues even at lower volumes.

The speaker is not designed to function for any significant duration at a regime where the protection is intermittently triggered. Have it repaired, and don't push it that far.

 

[Mort]

Or show clips where it's popping and the red light doesn't come on at all.

 

[mlsstl]

The more I read this thread, the more it looks like the OP is asking the speaker to play at a volume beyond its capabilities. I find it odd that a university student in the field of Acoustical and Audio Engineering hasn't bothered to measure or state the dB volume he's trying to achieve. I also noticed the video with the speaker's red light blinking was taken outside which even further stresses a speaker if one is trying to achieve a certain volume.

 

[antcollinet]

Any chance that one of the earlier repairs has replaced a driver with something that has shorter end stop limits.

I agree with everyone else - it sounds like a mechanical end stop to me. The cone is just moving too far. And yes - if you turn it up into clipping as you are doing - that is always a possibility.

And bear in mind a continuous tone will have much lower peaks than transients in music, even while playing at much higher power.

 

[TomLynas]

The more I read this thread, the more it looks like the OP is asking the speaker to play at a volume beyond its capabilities. I find it odd that a university student in the field of Acoustical and Audio Engineering hasn't bothered to measure or state the dB volume he's trying to achieve. I also noticed the video with the speaker's red light blinking was taken outside which even further stresses a speaker if one is trying to achieve a certain volume.

Outside, its capability to produce loud bass transients is about 90dB at 1m. If I put a butterworth LPF at 85Hz, the speaker can quite comfortably reach peaks of 110dB and sustained RMS levels of around 105dB.

I’ve not got a 7070a which handles low end and the speakers are able to get much louder, and the popping ceases.

Part of the training to be an acoustic engineer is testing the limits of my speakers and trying to understand the failure points.

I’m well aware I could buy PAs for a fraction of the price but the higher SPL does come at the cost of frequency response and directivity accuracy which I’m not willing to sacrifice, hence me pushing them this hard.

If I was to use them for a small party I would set a limiter on a minidsp a few dB below where the limiter has to kick in to prevent it from working too hard.

 

[LiveTek]

I could never get my 8030c to hit it's clip light, I can't imagine how loud the 8050 had to be to clip. Holy moly.

 

[Marc v E]

Pls make sure you take good care of your hearing. Iirc even 90 db over longer time can lead to damage, 105, 110 db for sure iirc within 10 minutes. It can't be repaired or restored to its previous state; it's forever.

Would be a good idea to wear hearing protection during such experiments.