#1
So I have a Peavey 4x10 TVX bass cab running through a Max Bass 700 head.

I was setting up for practice and during my drunken stupor I didn't realize that for some reason my volume levels had been abnormally high. I kicked it on and immediately realized(from a visual perspective AND and auditory perspective) it probably wasn't good for the speakers. It was up for no more than about 15 or 20 seconds. I could smell something abnormal though, some kind of burning.

I don't remember it giving me any problems for the rest of the practice session, I normally don't play with the master past 1 o'clock - when this happened it was at about 3 or 4.

Last night when I returned to practice, I realized immediately that my speakers sounded like they were blown. The sound is not consistent however, as it would at times seem clear but randomly get that farty kind of sound - even at very low volumes.

Made sure the problem wasn't coming from the bass or the result of any of my cables or pedals by plugging directly into the amp and using a different bass.

Upon examining the outside of the cabinet and speakers closely, it appears there are no rips or tears in any of the cones, they still look rather nice. I also noticed that when playing on them, the bottom two speakers seem to be doing more work than the top ones. The top ones are definitely still producing sound though.

My question is this: Is it possible to blow a speaker without tearing the cone? If the answer is no, then what do you think the problem/solution is?

This comes at kind of a bad time as the band is about to kick off a another set of local shows starting this weekend, and I don't have the cash to go out and buy another expensive bass cabinet.
Treble>Epiphone Prophecy EX - MXR micro Amp - MXR Blue Box - MXR Fullbore - MXR Noise Clamp - Vox AD30VT
Bass>Ibanez BTB505 - MXR Blowtorch - MXR D.I. - Peavey MaxBass 700 - Peavey TVX410
#2
I could smell something abnormal though, some kind of burning. Upon examining the outside of the cabinet and speakers closely, it appears there are no rips or tears in any of the cones, they still look rather nice.

A “blown” speaker (voice coil burnout) commonly exhibits no external indications of damage, because the voice coil is not visible without disassembly, but this is by far the most common sort of speaker malfunction. It results from a buildup of heat in the voice coil, from excessive amplifier power or “clipping” distortion, which overcomes the ability of the speaker design to dissipate.
#3
Quote by _LoveFuzz_
A “blown” speaker (voice coil burnout) commonly exhibits no external indications of damage, because the voice coil is not visible without disassembly, but this is by far the most common sort of speaker malfunction. It results from a buildup of heat in the voice coil, from excessive amplifier power or “clipping” distortion, which overcomes the ability of the speaker design to dissipate.


It's got nothing to do with power-amp distortion. It's because of the speaker being driven too hard. Simple as.
EH


"Show me war; show me pestilence; show me the blood-red hands of retribution..."
#4
So, some of you have determined a speaker may be blown. When I take this thing apart then what do I need to look for to determine which speaker(s) is/are damaged?

Since the bottom two speakers are working harder, is it more likely the top ones are damaged or is it the other way around?

Do you suggest I purchase new speakers for the cab? Is it okay to use 2 different brands or kinds of speakers in the same cab? Would it be cheaper to buy a new cab?
Treble>Epiphone Prophecy EX - MXR micro Amp - MXR Blue Box - MXR Fullbore - MXR Noise Clamp - Vox AD30VT
Bass>Ibanez BTB505 - MXR Blowtorch - MXR D.I. - Peavey MaxBass 700 - Peavey TVX410
#5
Quote by Vypor
So, some of you have determined a speaker may be blown. When I take this thing apart then what do I need to look for to determine which speaker(s) is/are damaged?

Since the bottom two speakers are working harder, is it more likely the top ones are damaged or is it the other way around?

Do you suggest I purchase new speakers for the cab? Is it okay to use 2 different brands or kinds of speakers in the same cab? Would it be cheaper to buy a new cab?



Ideally if you had a frequency generator you could hook it up to the speaker and it would be able to show you if the speaker was working properly, otherwise there really is no way aside from isolating it in the circuit to see if it sounds right when you use just the culprit speaker. It is possible to damage the voice coil which would ruin the speaker and you wouldn't be able to see and signs of damage at all.

Mixing and matching different speaker brands is ok, just make sure you replace it with something of the same resistance, so if you remove an 8ohm speaker put an 8ohm back into it. Its quite common to mix speakers to get a more unique tone, or for different sounds when you mic the cab up.
2011 Gibson Honeyburst LP Trad. w/ SD Whole Lotta Humbuckers
2014 Gibson Ocean Water Standard Plus
Marshall Haze 15W Head/Cab
Hughes & Kettner Tubemeister 5
#6
My question is this: Is it possible to blow a speaker without tearing the cone?
Yes

If the answer is no, then what do you think the problem/solution is?
The answer was yes

So, some of you have determined a speaker may be blown. When I take this thing apart then what do I need to look for to determine which speaker(s) is/are damaged?
Measure their resistance with a ohm meter. Resistance = approx 2/3 impedance rating
Move the cones in and out by hand. Listen for grating noise. Grating = damaged voice coil = low volume distortion.


Since the bottom two speakers are working harder, is it more likely the top ones are damaged or is it the other way around?
The ones that sound normal are the good ones. The ones that fart are the bad ones.

Do you suggest I purchase new speakers for the cab?
No, I suggest you get the bad ones re-coned if they are good quality ones.
If redone cost more than 1/2 new cost then buy new speakers.
Secondhand speakers are also often available.

Is it okay to use 2 different brands or kinds of speakers in the same cab?
Yes, but need to match size, impedance and power rating. Also good to match fixing centres otherwise woodwork needed.

Would it be cheaper to buy a new cab?
Almost certainly not unless second hand.
#7
Thanks for the input guys! I know it may seem like common sense, but I've never really had this kind of problem before because generally I'm pretty careful with my stuff. Only takes one night of foolishness I suppose.

Anyways, I found the replacement speakers on the Peavey website, they are Sheffield -1035's and they have a 300 watt peak.

Now, I was always under the impression that this head that I have matched this cab (Peavey Max Bass 700) but its a 700 watt amp, and these speakers have a 300 watt peak.

Since there are 4 speakers, is the power distributed differently to accommodate for all the extra power? Or is this rig just kind of a liability?

I also noticed that Peavey offers some Blue Marvel speakers that have a 600 watt peak and only cost about $10 more. Would that be a better/safer alternative?
Treble>Epiphone Prophecy EX - MXR micro Amp - MXR Blue Box - MXR Fullbore - MXR Noise Clamp - Vox AD30VT
Bass>Ibanez BTB505 - MXR Blowtorch - MXR D.I. - Peavey MaxBass 700 - Peavey TVX410
#8
If my memory serves me well the wattage peak of your speakers correlates to the amount of headroom you have because of the power needed to overdrive the speaker. I think. I very well could be wrong and if I am, please do correct me.

So yea, I'd go for it. Especially if they're only $10 more.
#9
The Blue Marvel speakers sound better, but really you would have to replace all the speakers in the cab with those for the best results.
EH


"Show me war; show me pestilence; show me the blood-red hands of retribution..."
#10
I know this thread is old, might need to make a new one to update. I took the cab to a shop, and he ran some tests on it and insisted that nothing was wrong with the cab. He plugged it up to an amp, and it seemed to play fine.

I was baffled. Brought the amp back to practice happy, only to find it doing the same thing when I got there. I guess it doesn't really sound like a blown speaker, but moreso like a shorted out cable.

The tech guy kept mentioning something about a crossover, that I could of burned some component on the inside, but he did check and said that it did not seem to be the case. Could some solder have knocked loose or something like that?
Treble>Epiphone Prophecy EX - MXR micro Amp - MXR Blue Box - MXR Fullbore - MXR Noise Clamp - Vox AD30VT
Bass>Ibanez BTB505 - MXR Blowtorch - MXR D.I. - Peavey MaxBass 700 - Peavey TVX410
#11
Maybe you should try verifying it's not the amp or a cable. Got any other heads or cables around you can try?
#12
Quote by Preacher403
Maybe you should try verifying it's not the amp or a cable. Got any other heads or cables around you can try?


Indeed, I have plenty of cables to try, and have been using a different cab since this one started giving me trouble.

The tech guy suggested the problem may be the head, but the head works fine with the other cabs I plug up to. I have both the Peavey max 450 watt head and the Peavey Max 700 watt head, tried both of them on this cab with the same result.
Treble>Epiphone Prophecy EX - MXR micro Amp - MXR Blue Box - MXR Fullbore - MXR Noise Clamp - Vox AD30VT
Bass>Ibanez BTB505 - MXR Blowtorch - MXR D.I. - Peavey MaxBass 700 - Peavey TVX410
#13
It sounds to me as if you have blown two of the speakers, though a poor connection could be a possibility too. there are a number of ways a speaker may fail. The coil may get too hot and then go open circuit or the coil may distort with the heat and start rubbing against the magnet. Push gently on the cone and you can hear the scratching if this is what is wrong, This can lead to intermittent problems as the magnet shorts the coil and then clears as the speaker moves. Another common problem is if the coil hits the back of the magnet which happens at much less than the rated power with deep bass. Again this can distort the coil. Another common failure is where the lead out wires break away from the coil agin this can be intermittent at first.

whatever has happened the speakers in question need replacing or reconing. you can't really mix speakers in a bass cab the way you sometimes can in a guitar cab. To handle the bass the cab is fairly carefully matched to the speakers so replace them with matching speakers. In the UK old Peavey 4x10s are fairly cheap at the moment as most people want smaller and lighter, have a look and see if it is true over there you might get a bargain set of four working speakers for less than the price of two new drivers.
#14
Quote by Phil Starr
The coil may get too hot and then go open circuit or the coil may distort with the heat and start rubbing against the magnet. Push gently on the cone and you can hear the scratching if this is what is wrong.


This was the first thing the tech guy did - he took off the grill and pressed gently on all the speakers and told me that it didn't sound like there was any damage to the coils - thats when he said it might be the crossover. He opened up the back control panel where the tweeter volume/Speaker cable input is located, and proceeded to show me that nothing was out of the ordinary on that particular unit. He said if there was damage, it would be apparent via burn marks.

This is when he started asking me about the amp I use. He plugged up a acoustic head he had there in the shop and it seemed to work ok, but did not play on it for an extended period of time.

This is why I'm confused. When I brought it back to practice it did work for a very short period of time before it started making this noise again. The noise isn't consistent - meaning that it seems to crackle randomly when the signal is passing through it. Like I mentioned before, it sounds much like a "shorted out" instrument cable.

Quote by Phil Starr

whatever has happened the speakers in question need replacing or reconing. In the UK old Peavey 4x10s are fairly cheap at the moment as most people want smaller and lighter, have a look and see if it is true over there you might get a bargain set of four working speakers for less than the price of two new drivers.


Yeah, the speakers are 10in Sheffields. I don't want to spend the money to replace them if I'm not sure they are the problem. The other thing is, I'd rather not mix and match speakers and if I was going to replace them, I may as well opt for the more expensive Blue Marvels anyways as they can handle much more power and are only about $20 more expensive than the Sheffields. Problem with that is, I'd have to buy 4 instead of just 2.
Treble>Epiphone Prophecy EX - MXR micro Amp - MXR Blue Box - MXR Fullbore - MXR Noise Clamp - Vox AD30VT
Bass>Ibanez BTB505 - MXR Blowtorch - MXR D.I. - Peavey MaxBass 700 - Peavey TVX410
#15
It is really hard to diagnose any intermittent fault. they never go wrong when you want them to. it is impossible to do this over the internet.

I doubt if it is the crossover but you can disconnect this altogether, the horn/tweeter won't work of course but the rest of the speakers should work as normal. TBH any decent tech could have tried this, though it is so unlikely I would only have looked if the tweeter was malfunctioning.

If you are handy you could try only connecting one speaker at a time to the jack, keeping the volume fairly low. the speakers are wired together in pairs so a fault in one speaker will show up in both of the pair, you may only need one speaker replaced and trying them one at a time will show which one is at fault.

Your cab is ported which means the cab is tuned to the Sheffields, the Marvels may be a better speaker but might not work as well in a cab tuned to Sheffields.