speaker falls silent

khoomeizhi · November 24, 2012, 05:29:11 AM

i'd never experienced this before:

one of the speakers in my 215 cab has fallen totally silent. there's no obvious wire-disconnections, nothing obviously wrong with the speaker itself (no rips, etc)...i replaced the other speaker not that long ago - this is the other one. used another head to double-check, and a different speaker cable, too, just to be sure, and it's pretty clear it's the speaker that's the issue. i don't have the biggest experience with this stuff, but i'd never heard of a speaker just falling silent - it's not greatly reduced in output, just totally dead.

so the questions: what's the explanation for what happened? my assumption is that that speaker has (probably permanently?) shit the bed, and i need to replace it. is this true or can it somehow be fixed? if i were to play through this cab as-is, would i be putting the other (new) speaker at risk? what about swapping out the dead speaker with the one with the cracked cone that i replaced before? i know it wouldn't sound the best, but is that a 'safer' way to run that cab (our guitarist just got a new amp, and i'm not sure that i want to use my old 115 combo to try to compete with it - yes, she cold turn down[and probably will], but would running my 215 with a slightly busted speaker be better 'electrically' (as far as danger to head or the other, functional speaker) than trying to run it with a dead speaker in it?)...i think i know some of these answers, but i'd be happy to learn better...

too many parentheses; did not read? any wisdom? i'll be bringing both the 115 combo and the older broken speaker to practice today just to be safe - kindly hit me with knowledge between now and about 3pm EST if possible.

Mr. Foxen · November 24, 2012, 12:15:28 PM

If it has gone fully open somewhere it will just go quiet, if you can get at it measure the resistance at the tinsel wires going from cone to lugs, will tell you if it is just disconnected somewhere else. Running a cab with one dead speaker is going to risk the other speaker, because the dud speaker will mess with the cab tuning as a passive radiator, so the speaker will fart really early. Running with one slightly fucked speaker is also risky as the sound of the bust one might cover the sound of the other one protesting.

khoomeizhi · November 24, 2012, 12:42:07 PM

not sure if i understand the passive radiator thing. is that the reason that the functional speaker would be 'protesting' when playing alongside a ripped speaker, too? can you explain that more?

Mr. Foxen · November 24, 2012, 01:05:19 PM

Quote from: khoomeizhi on November 24, 2012, 12:42:07 PM
not sure if i understand the passive radiator thing. is that the reason that the functional speaker would be 'protesting' when playing alongside a ripped speaker, too? can you explain that more?

Air pressure in a cab controls/limits the speaker movement, as does the resonant frequency of the port, depending on if it is a sealed or ported cab. If there is a loose speaker, it allows the working speaker to move further in an uncontrolled way, which means it is easier to break as not much power will push it to its limit. The hole in the ripped speaker will let air through and mess with the cab pressure too. The dead speaker will suck in when the other speaker moves out due to the air pressure in a sealed cab, not an ideal thing.

khoomeizhi · November 24, 2012, 02:22:59 PM

but less so in this case because it's not sealed? big ports.

i know, i should just use the 115 for now...

Mr. Foxen · November 24, 2012, 02:30:45 PM

Quote from: khoomeizhi on November 24, 2012, 02:22:59 PM
but less so in this case because it's not sealed? big ports.

i know, i should just use the 115 for now...

The port tuning goes out the window with a dud speaker, so the driver will unload much higher up than if it is working correctly.

khoomeizhi · November 24, 2012, 02:55:39 PM

i think i'm with you. dud speaker meaning not playing at all + ripped ones too?

Mr. Foxen · November 24, 2012, 02:58:44 PM

Quote from: khoomeizhi on November 24, 2012, 02:55:39 PM
i think i'm with you. dud speaker meaning not playing at all + ripped ones too?

Ripped but moving is a hole in your cab, sure it won't sound great either. Not moving but intact cone is a passive radiator, effect on the air pressure in the cab is sort of the same, in that it messes with the tuning/driver loading, making the speaker act like it is in an open backed cab at some frequencies.

khoomeizhi · November 24, 2012, 03:06:36 PM

i wasn't expecting it to sound great...mostly just asking for temporary (read: can sound kinda bad) use while the new new speaker is en route.

so specifically - if i switch the dead speaker out for the damaged one (i.e. still plays but is cracked/ripped), aside from sounding bad, am i risking actual damage to the remaining speaker? we're probably talking one several-hour practice, and it's not going to be cranked.

i appreciate your patience with me, by the way.

chille01 · November 24, 2012, 03:40:15 PM

A long shot, but I did see this happen to a friend of mine once. If the speaker cable inside is just connected with push on spades rather than soldered on, it's possible that one of the connections just rattled off or came loose moving it around. If the speaker is front loaded, you could just pull the speaker out and verify its connected properly. Unless you already did that, in that case ignore me.

jibberish · November 26, 2012, 06:11:16 PM

yes, fully open = dead silence

you can usually inspect the speaker wires from just about where they connect to the voice coil, which is on the front, across a bit of the face(usually glued down}, THROUGH the cone, across the gap to the frame, and finally to the attachment lugs or lug board. maybe leave the dust cap in the center alone. you don't really need to knock that off at this time lol.

the braided flexible part jumping from the cone to the frame is subject to work hardening after a bazillion flexes during its life.

look around the solder points by the lugs, check the wires from the lugs to the cabinet lugs, like the detached spade lug example, and finally look around the jacks and cabinet speaker in board. I hate 1/4" jacks as speaker jacks btw, but peeps are ok with them , so ok heh

khoomeizhi · November 26, 2012, 08:59:19 PM

it's gotta be somewhere in the individual speaker itself, but i'm damned if can figure out where. i swapped in the old cracked one just to see and it plays...i dunno. maybe someone can locate the issue and fix this speaker, but i'll be better off with it's replacement anyway. the dead speaker will stay silent for some time, methinks.

(the real replacement is on its way)