Speaker "farting"

[pravus]

My understanding from car audio was that the danger from clipping came when the power amp clipped and sent distorted signals to the drivers which caused them to permanently damage the cones and surrounds. That was what I was told to explain why speakers sound distorted even at low volumes after they have been pushed hard. I've always worried about the same thing with instrument audio but the amplification is done so differently. Was I lied to or is it just not possible to push the power amp section to clip? I fully get over driving the pre-amp section to get a distorted sound, but what about after that?

 

[BurningSkies]

My understanding from car audio was that the danger from clipping came when the power amp clipped and sent distorted signals to the drivers which caused them to permanently damage the cones and surrounds. That was what I was told to explain why speakers sound distorted even at low volumes after they have been pushed hard. I've always worried about the same thing with instrument audio but the amplification is done so differently. Was I lied to or is it just not possible to push the power amp section to clip? I fully get over driving the pre-amp section to get a distorted sound, but what about after that?

Power amp clipping as a speaker sees it is no different than preamp clipping or distortion as caused by a distortion pedals (which is another form of clipping). Speakers are damaged by either over excursion or over heating.

 

[archtop2]

Hi , put the driver in a small DiY box à la Markbass 1.05 cuft , I know it's far small, vented, still get some farting on E and somewhere above.

Here is Eminence spec about the speaker cone displacement in a small vented cab 1.4 cuft tuned for 54,84 Hz.
The speaker reaches limit at 70Hz and below 40 Hz. I can ear this with mine.

A smaller closed cab 1.15 cuft shows a better containment of cone displacement , but one loses the bass bump form the vent

Those spreadsheet clearly shows the speaker reaching its limits with no more than 125w, I walk on eggsshell with this speaker choice. It's probably my cab design sending the speaker beyond the limits as those show no margin.

I'd put damping wool before trying to close mine which seems the safest option, or more uncertain deal with the vent size, lastly investing in a more solid speaker option.

 

[Arjank]

Bought a used Eminence Basslite S2012 and tried it connected to my brand new Mrkbass LM250.

Volume at 12 o'clock I get the speaker farting at 0:28 video below



Does it miss a cab or the speaker has a problem?

That kind of farting is what I experienced with the Deltalite 2510 MkII and I don't like it. This starts to kick in when the voice-coil is leaving the magnetic field, with some drivers this happens gradually and with some it's exponentially. It depends largely on the motor design.
When I bought the Oberton 10B200 this farting started to happen with much higher excursions.
My personal preference is a driver that says linear and that the distortion rises gradually. This also keeps the cad/driver alignment in place at higher volumes, when a speaker farts it's TSP change and coherence between cab and driver is gone.

Archtop2, I see you live in France, maybe you should try one of the 12" drivers from PHL(French product). That stuff is on a different level then Eminence.
Invalid Link Removed

 

[archtop2]

Yep, nice high end stuff indeed but expansive for my cheap DiY Markbass clone.

Not in my 12" scope but interresting here is how another Eminence product CA154 handles power for 100 bucks and larger 3.75cuft enclosure, no Xmax indicated but 8mm Xlim.

Obviously not the same limit(ation)s

 

[Downunderwonder]

You should start your own thread. The box you have is too small unless you seal it. TB'er Fdeck has a compact 2512 shelf port design which you could adapt for your s2012.

Yep, nice high end stuff indeed but expansive for my cheap DiY Markbass clone.

Not in my 12" scope but interresting here is how another Eminence product CA154 handles power for 100 bucks and larger 3.75cuft enclosure, no Xmax indicated but 8mm Xlim.

Obviously not the same limit(ation)s

 

[archtop2]

Progressed on the question with some other interresting informations from here : Invalid Link Removed

Damping alters reaction of the speaker to the volume simulating a larger box.

One good clue for this is how Markbass puts a thicker wool layer in the small 12" than in the 15" .

Knowing this I ordered twice the damping wool I planned for 2" thick, and speaker flutter has now disappeared as I previously enlarged the cab to 1.3 cuft that wasn't enough though.