software

So was busy practicing with my band today and all of a sudden before we began the next tune my tone went to hell on me. After some investigation we found that something it wrong with the speaker cab.

We switched guitars, amps, cables, cabs, everything.... it all came back to the cab being funky.

Basically every time i hit a chord really hard i get this fuzzy, whoompf-ing, crackling noise coming out. Sustain isn't real good anymore and the tone seems weak. Did I blow something? Is this cone cry? What's up? How do I fix it, if its fixable?

Please advise.

~B


Originally Posted by B2DSo was busy practicing with my band today and all of a sudden before we began the next tune my tone went to hell on me. After some investigation we found that something it wrong with the speaker cab.

We switched guitars, amps, cables, cabs, everything.... it all came back to the cab being funky.

Basically every time i hit a chord really hard i get this fuzzy, whoompf-ing, crackling noise coming out. Sustain isn't real good anymore and the tone seems weak. Did I blow something? Is this cone cry? What's up? How do I fix it, if its fixable?

Please advise.

~B

Check your connections first...After that the only thing you can do is to substitute another speaker for the one you think is bad...I hope it's just a connection issue for you though..

I ran into something very similar B2D, my speaker ended up being blown and yours may very well be too.

It's either a loose connection or a blown driver...my money's on blown driver. A loose connection usually cuts in amp; out but sounds fine when it's quot;inquot;.

1 for a blown driver.
lose connection makes static noises, cuts the signal, but doesnt fart or oomph out

How could I have blown it?!?!

The cab will handle 135 watts and I run a 100W Legacy with an attenuator through it... and nothing other than my amps have ever been used through it! I haven't even gigged it with the current speaker setup.

What kind of speakers are in it?


Originally Posted by GearjoneserWhat kind of speakers are in it?

A used Celestion V30 that I got from Krankguitarist and a brand new Eminence Wizard.


Originally Posted by B2DHow could I have blown it?!?!

The cab will handle 135 watts and I run a 100W Legacy with an attenuator through it... and nothing other than my amps have ever been used through it! I haven't even gigged it with the current speaker setup.

Ehhh...let's go back to school shall we?

When you crank up an amp and make a noise the speaker responds by moving in and out, one complete movement is called a cycle and there are thousands of 'em per second. A real world example that everyone can relate to would be A440. In this case, the speaker (or tuning fork, guitar, piano etc) will vibrate 440 times in one second and that produces the note that we hear, put that through an amp amp; speaker and the speaker will move in and out 440 times in one second. The louder the amp is the farther the throw on the speaker is and if the amp is clipping and sending square waves out, the speaker will actually go out and stay out and come in and stay in and this of course happens thousands upon thousands of times in matter of seconds. Granted, the nature of the beast is that square waves usually happen only with solid state amps and not tube amps but the effect is the same.

That's why when dealing with solid state amps in the audio world you always want to overrate the speakers to the amp, not the other way around. Running a 500 watt amp with a 300 watt speaker is good because you'll hear the speakers start to give up before the amp clips. But running a 300 watt amp into 500 watt speakers is bad because the amp will clip and send a square wave to the drivers, you’ll never hear the speakers giving up until they actually do. Tube amps are another matter because generally, they don't create square waves and we call the ‘distortion’ warm or phat or whatever you want to call it.

Anyway...

As the speaker is making its round trips in amp; out the glue amp; magnet in the voice coil get hot. Get it hot enough for long enough and they can start to melt which will obviously change the sound. If amp; when they melt enough...POOF!!!

No more speaker.

There are a lot of other things that can cook a voice coil; anything from damage to the speaker surrounds, volume, and ultra or sub sonic frequencies which are things you can't hear but are still being produced or reproduced by the chain...Whammy pedals amp; effects are great for creating some of that stuff. Hell, one time I cooked an amp by using a buffer box that's designed to boost a guitars signal so you can use a 100' feet or longer cable and not have any sonic degradation. Well, a byproduct of the design was a 75kHz tone which is so high up there dogs probably can't even hear it...but it cooked a Bogner and 4x12 cab with Weber's so there 'ya go!

Now, to see if you cooked a speaker you need to have access to the front of it which usually means taking it out of the cabinet. Lay the speaker down and put your fingers in a circle around the dust cap (the center of the speaker) about halfway between the cap amp; the surround, or outer part of the driver. Push gently but firmly and listen to the sound of the speaker. If it makes a rubbing and/or clicking sound the speaker is dead. If it makes no sound at all then the speaker is probably A-ok and the problem lies elsewhere.

Hope that helps a bit,

Whoa ,that is some good info...

J Moose...

... I understand everything you said, but I still can't understand why I would've blown a speaker other than one of those freak accidents you mentioned. For the record I have a fulltone OCD and a crybaby wah in front of the amp. There's a Gigadelay in the effects loop. Thats all.

I don't throttle the amp out even when it IS attenuated. I usually put it at 5 and keep it there. I use it at what you would call gigging levels about twice a week.

I'll go open it up and check the speakers now. If it IS blown I'm assuming there's nothing I can do other than sell it for dirt cheap for someone who wants a reconing project.

Man, a speaker could pop for all kinds of reasons and not just the freak stuff. Sometimes plain old fatigue will take one out or maybe it was just defective. I've also seen 'em go from not being used and sitting in storage in a hot garage or warehouse, damp conditions...whatever. That stuff will age amp; wear a driver down before you play a note through it. Drivers are like guitar strings, expendable stuff that's a cost of doing business. Sometimes they'll last for years and years and sometimes you'll get a few months. Have you ever had the chance to A/B a brand new speaker with an aged one of the same model? That's kind of ear opening.

You said you have mis-matched drivers in the cab right? What are the chances that the power rating isn’t well matched and one of 'em was taking the brunt of the amps juice? Is the cab wired in series or parallel? If it's parallel that shouldn't happen but it might in a series wiring. As an engineer I've run into multi-speaker cabs that have one driver out and you'd never know it until you put a mic on the bad speaker. In that case it'll muck with the impedance and power handling...throwing the whole head/cab recipe out of wack.


Originally Posted by J MooseMan, a speaker could pop for all kinds of reasons and not just the freak stuff. Sometimes plain old fatigue will take one out or maybe it was just defective. I've also seen 'em go from not being used and sitting in storage in a hot garage or warehouse, damp conditions...whatever. That stuff will age amp; wear a driver down before you play a note through it. Drivers are like guitar strings, expendable stuff that's a cost of doing business. Sometimes they'll last for years and years and sometimes you'll get a few months. Have you ever had the chance to A/B a brand new speaker with an aged one of the same model? That's kind of ear opening.

You said you have mis-matched drivers in the cab right? What are the chances that the power rating isn’t well matched and one of 'em was taking the brunt of the amps juice? Is the cab wired in series or parallel? If it's parallel that shouldn't happen but it might in a series wiring. As an engineer I've run into multi-speaker cabs that have one driver out and you'd never know it until you put a mic on the bad speaker. In that case it'll muck with the impedance and power handling...throwing the whole head/cab recipe out of wack.

Well as I said there's an Eminence Wizard and a V30 in there. The V30 handles 60W and the Wiz handles 75W. It's a 16 ohm cab, which means two 8ohm speakers wired in series. The positive lead from the speaker input jack goes to the Wizard first and then links to the V30.

I'm going to knock the amp (Legacy) into the 50W setting w/ no attenuator and then run it through each speaker by itself. That should ID the culprit.

I have a feelings its the Wizard because a) The V30 was used but had been working fine according to krankguitarist b) people have complained of high rate of defectiveness in the Redcoat line.


Originally Posted by B2DI'm going to knock the amp (Legacy) into the 50W setting w/ no attenuator and then run it through each speaker by itself. That should ID the culprit.

Sure, that's one way to test 'em and a GREAT way to fry the amps output tranny and other stuff in the process...most likely taking screen resistors and maybe tubes along for the ride.

When you run an amp into a blown speaker there's essentially no load there and the amp is basically driving a short. Technically there is a load but for all intents amp; purposes there isn't because it's so low and well outside of the normal safe operating range of the amp.

Test the drivers the right way, it'll take longer but it's the only way to do it without damaging anything else. Pull the speakers out of the cab and check 'em with the method I described above.

Peace,


Originally Posted by J MooseSure, that's one way to test 'em and a GREAT way to fry the amps output tranny and other stuff in the process...most likely taking screen resistors and maybe tubes along for the ride.

When you run an amp into a blown speaker there's essentially no load there and the amp is basically driving a short. Technically there is a load but for all intents amp; purposes there isn't because it's so low and well outside of the normal safe operating range of the amp.

Test the drivers the right way, it'll take longer but it's the only way to do it without damaging anything else. Pull the speakers out of the cab and check 'em with the method I described above.

Peace,

Well here's a riddle for you then...Pulled the speakers out and did the push test you described for me. The result? No noise. No rubbing or clicking. No NOTHING.

I thought it was a bad connection so I tightened everything up and checked everything for looseness. After everything was fastened down, I plugged in the amp again and after a few moments, the crackling and whoompfing started again. BOTH speakers are doing this.

I did notice that this ONLY happens with the dirty channel, and when I play loudly and hit chords hard. I recognize it immediately because the sustain gets killed right away.

Anyways I turned the amp off right away and I proceeded to practice for the rest of the day through a Marshall 1960A cab I borrowed from a friend. The amp sounds great and performs flawlessly. No whoompfing or farting to be heard.

So the push test produces no results, it's not a bad connection, it's not the amp. So the speakers act as if they're blown (on the dirty channel only) but do not click or rub when pushed. Could they be blown and not seem like it from the push test?

This is so damned frustrating. I have a theory as to what is causing this but I'll reserve it until I get an answer from J.

Your move, J.

Is this the Legacy combo or a Carvin cab?


Originally Posted by WatrobaIs this the Legacy combo or a Carvin cab?

It's a Legacy head through a 2x12 Trutone cab.

I say try it through each speaker individually anyways. You can have your amp on for 2 minutes without a load and not **** anything up.


Originally Posted by DeadSkinSlayer3I say try it through each speaker individually anyways. You can have your amp on for 2 minutes without a load and not **** anything up.

Thats what I did and as I said the amp performed great. It turns out both speakers are doing this.

anyone?