8020A weird ~70hz resonances from speakers - Forum

What signal did you use to test ? Sinus signals ?

The resonances can be heard on all signals with low-end material, but a 70hz sine wave is the easiest and clearest way to make the speakers resonate, as I said in my first post.

Sinus/sine signals cannot be used, that is why I asked, which was not clear from your first post. In an aluminum enclosure you will not get a 100% resonance free behaviour of all parts at high volumes. I have some resonances as well in the 8240s....but with dynamic amd full frequency material, these are far below the thresholds to separate it accoustically during playback.

If you are really sure you can hear it on music, move the speaker to check unlucky placings that support any rattle. In the end your speakers maybe broken. I'm sure Genelec will answer this....if it is like a 0,5 to 1Hz steep rattle, I have my doubts. Wish you luck.

PS: sorry, just reread and see you said sine sweep.....

Thanks for your answer.

The resonance frequence is not exact, there are some peaks and troughs between 60hz-80hz so it is a larger area.

I'm fairly sure that there is something wrong with my speakers because now I tried this sine wave test on a pair of 6010 and there was no rattling resonances at all such as I have, even when I cranked up the volume a lot.

I have tried holding the speakers in my hands "in the air" without any desks, stands or other stuff and have moved to different rooms so I am sure that it is the speakers resonating and not anything else. What is weird is that both speakers are showing the same symptoms, although not at exactly same volumes. The manufacturing dates on the speakers are the same, though, and serial numbers are very close so it might be a manufacturing thing.

I've been using a pair of 8020A's for over 4 years now and a year ago or so noticed that both speakers were starting to "rattle" or resonate inside when frequencies around 70hz were played at slightly higher volume levels. The resonances are not equally loud on both speakers but both speakers resonate to some degree. This is not easily heard on music material but very easily recognized if I play a sine sweep through the speakers.

Help & advice would be nice,
Matti S.

Hi Matti,

The rattling noises you are hearing are definitely not normal. Unfortunately it looks like your speakers will require professional service. If you are from Finland (just guessing by your name), please contact our service department: http://www.genelec.fi/yhteystiedot/ Otherwise contact your local distributor: http://www.genelec.com/sales-network/

Sinus/sine signals cannot be used, that is why I asked, which was not clear from your first post. In an aluminum enclosure you will not get a 100% resonance free behaviour of all parts at high volumes. I have some resonances as well in the 8240s....but with dynamic amd full frequency material, these are far below the thresholds to separate it accoustically during playback.

Hi Andreas,

It seems that there is some kind of misunderstanding here. In no way an aluminium enclosure is worse than for example MDF enclosure when it comes to cabinet resonances - it's actually the other way round. And in any case, every Genelec speaker, whether be made out of aluminium or MDF, are designed to be 100% resonance free when it comes to audible resonances. Of course there is a small chance that something inside the cabinet gets loose due to a shipping damage or possibly badly installed or defective part etc. But as a general rule, you shouldn't be able to hear any kind of resonances (port chuffing noises not included) from any Genelec speaker.

Many thanks for your reply, I will contact support immediately!

In no way an aluminium enclosure is worse than for example MDF enclosure when it comes to cabinet resonances....every Genelec speaker, whether be made out of aluminium or MDF, are designed to be 100% resonance free when it comes to audible resonances

Good to hear Illka,

and it was not my attention to say so. Will double check my 5 speakers as well, as I was under the impression that at high volumes smallest resonances, like in the protective grill or "inside" from components as said above can be normal, especially with steep and loud sine signals....

I realize this thread is old but one of my 8020s started doing this too (I think it's the same issue) so I thought I'd post some info for future googlers.
What it is is a rattling from the chassis itself, that seems to originate from the woofer grill. Sounds very different from a busted woofer. Solution: Adjust the two bottom hex socket bolts (most probably tighten) until the rattling disappears.
I'm a bit disappointed in Genelecs attitude towards this kind of sinmple problemn. Saying you need a tech to do this for you is ridiculous. This is a design flaw that seems to affect a lot of users. Information on how to remedy this should be readily available. The fix takes less than five minutes (including setting up a test tone), so there is no need to interrupt your business or pay for repairs. Genelec needs to change it's attitude regarding simple problems like this.
In fact I brought the speaker to Genelecs certified tech once already but they couldn't find the problem. Since the enclosure itself is the problem I guess transporting can shift things around enough for the rattling to disappear. Hell, even putting the speaker on its' side can make it disappear.