Me and my friend were playing a bass and a keyboard at the same time out of his bass amp using to different inputs at a fairly high volume. Suddenly we heard a low pitch fuzzy distorted crackling sound and now there is no sound at all. Have we blown the speaker? The bass amp is a 130 watt stage 115 p it's very old. Please help, thanks.
Either you damaged the voice coil, or something else inside the amp. Kind of hard to troubleshoot long distance, but I'd say you definitely did some damage.
Usually when you turn it on you hear a pop from the speaker and a little bit of buzz but now there is nothing. That might give some more information it's like as if nothing is plugged in or as if the speaker is totally dead. 30 mins later it started working for a few seconds and died again. Would that be the speaker or the input jacks?
that sounds more like circuitry is broken, not just the speaker's coils. i could be wrong
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Could we have blown out the circut. The amp has 4 inputs with 4 separate channels one channel was the bass and one was they keyboard. They keyboard was being playing very loud on a super bass synth sound and the keyboards volume was all the way up... Anyways is this fixable?
Based upon your added information, I'd say you have some component problems. It's likely repairable, depending on what you fried. Once you get it fixed, don't do that again.
You can hope for a cheap repair, but you're not likely to get it. Unless you know what you're doing, I'd take it in for repair. What you could try is plugging it into a second cab, if you have one. That will verify the speaker is good/bad. If it still doesn't work, then it's time to take it in. Most guitar shops have an electronic tech. Depending on what you damaged, how long it takes to troubleshoot and how expensive the part is, you could be looking at over $100 for your repair, including labor. Don't be surprised if it's $150, or more.
Don't do that, or you'll be repairing another piece of equipment.

Only connect the output of the head into a speaker, do not connect it directly to anything on a PA. If it's not blown before you do that, both it and the PA will be after you're done. Probably best that you take it in for repair.
It sounds like a burnt out speaker though as someone has said you can't really diagnose over the internet. When a speaker burns out the heat either melts the glue hoding the voice coil in place and/or distorts the coil former. Either way the coil is now rubbing against the magnet. If you go on passing a signal through it will scratch back and to and may even free itself for a few seconds. Eventually it will short against the magnet and could take out your amp.

Given your current state of knowledge you aren't going to be able to fix it yourself. If you want to confirm then connect the amps ouput to the input of a PA speaker, keeping the volume down really low. If it works the amp is ok and it's the speaker. You could also try pushing the speaker cone very gently with a cup (to get even pressure) if you hear a scratching noise its dead.
Usually when the amp is off and you plug your bass into it there is still a little bit of sound from the bass. Now there is nothing is this because the speaker is dead?
I tried connecting it to a pa speaker and no sound! It must be the amp then. When you plug in something the input jacks shift back into the amp and when you pull it out it shifts foreward. Could it be loose wires cause all four of the input jacks don't work
The next step is to try connecting the speaker to another amp (again turned down ). there should be two wires connected to two tags on the speaker. Just connect one to the pin of a jack and the other to the sleeve. The speaker should work normally.