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Cab issue

#3
Way too little information at this point for me to start assuming speakers need to be replaced. As an example, if you have an active bass something as simple as a 9 volt battery replacement could be the entire solution. Can you share what troubleshooting you've done to narrow this down to the speakers themselves?
 
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#4
Its 1984 baby said:
Are my speakers blowen?
Click to expand...

You really haven't provided enough info to answer this question.

The first thing I would suggest is the 9V batter test. The idea is to apply 9V to the cab (for a short period of time) and observe the speaker cones. All of the cones should move in the same direction. If they move in opposite directions, either they are hooked up out of phase or some of the drivers are dead.

As far as replacing the drivers? You have to choose drivers that are compatible with the cab. In order to get good results you need to measure the internal dimensions of the cab and any ports. Then you model how various drivers will work in the cab, until you find a driver that is a good match. If you just drop a random set of drivers into the cab, the odds are not very good that they will work well.

Drivers are described by Thiele-Small (T/S) parameters. The various T/S parameters describe the driver's electro-mechanical characteristics. Choosing an appropriate driver is a lot more involved than considering sensitivity, power handling, and frequency response. RMS power handling only relates to how much power the voice coil can handle.

With a bass cab, you need to be more concerned with mechanical power handling below 100hz. Mechanical power handling below 100hz is often significantly less than the driver's RMS power rating. Also Mechanical power handling is determine by the driver's T/S parameters and how they interact with the cab's internal volume and port tuning. So if you put the driver in different cabs, the mechanical power handling will change.

If your drivers are damaged, buying a new set of OEM replacement drivers will maintain the cab's original performance. However, this may not really be cost effective because a set of four drivers is likely to be fairly expensive. Additionally the OEM driver may no longer be available. Buying a working cab may be a better option.
 
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#5
Its 1984 baby said:
Hello, I have a Peavy cab 4x12s. I've been trying to get my rig going. But when I plug in my bass, it is very weak sound. Are my speakers blowen? What is a good replacement company to buy some speakers?

TIA
Me
Click to expand...

Jumping to conclusions can be costly and still not fix the problem. This requires systematic troubleshooting procedures. Some of these you might be able to do yourself.

Do you have access to another bass cab (maybe borrow one?) that you can try with your amp?

The important thing in troubleshooting is to only change one thing at a time and re-evaluate the situation before making other changes.

If a different cab gives the wanted results, then you can conclude that it is your cab or something related, like the speaker cable, being the cause. Though a cable problem seems unlikely in this scenario. But it's something easy to try. Be sure you are connecting with a speaker cable and not an instrument cable. Outwardly, they can look a lot alike.

If you are still experiencing the same, or similar poor operation with a different cab, then this points to the amp and anything associated with it, or connected in front of it. Bass, cable(s) effects, or other boxes hooked in the chain connected to the amp input.

If your amp has an effects loop (aka send/receive jacks) on the back, try inserting an instrument cable between the two jacks. If this fixes the problem, you can just leave the cable in place. Or take it to an amp tech to service or replace the jacks.
 
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#9
Mike Caldwell said:
The mentioned good ole 9 volt battery test is a good place to start.
Click to expand...

To do this requires accessing the individual speaker terminals.

You will need to disconnect the cabinet wires at the speaker terminals. Best to unhook, test, and replace wires for one speaker at a time rather than unhook them all.

Take a battery and touch the leads to the speaker terminals that are disconnected from the cab wiring.
Rinse and repeat for each speaker.

Be sure to always have the battery plus and minus terminals touching the same terminals on each speaker.
There is normally some marking near the terminals to indicate polarity.

Temporarily touch the battery terminals to the speaker terminals. (Obviously you will need some wire.)

First listen to the sound of the speaker thump and compare to each other in the cab. Hopefully they all sound the same. Repeat several times to get a sense of the sound.

Also notice if the cones all move in the same direction with battery connected in the same way on each. If any of the speakers had been wired backwards, aka reverse polarity, that can cause weak output.

Reconnect the cab wires to the speakers in the way they were when you started, unless you find a polarity reversal, then fix that.

Now that the speakers are reconnected, touch your battery to the terminals of any one speaker. Be sure all the speaker cones move in the same direction. If so, button things up and try it with your amp again.

This is a static test. It won't uncover dynamic issues. But as mentioned, it's a good place to start.
 
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#13
Its 1984 baby said:
Hello, I have a Peavy cab 4x12s. I've been trying to get my rig going. But when I plug in my bass, it is very weak sound. Are my speakers blowen? What is a good replacement company to buy some speakers?

TIA
Me
Click to expand...
If it's one cabinet, it's a guitar cabinet.

Peavey doesn't make 412 bass cabs.

You can plug a 1/4" cable into the input of the cab, and touch a 9v battery to it. The speakers will move outward. If a speaker sucks in instead, that speaker is out of phase. Pull it out and reverse the leads on the speaker. That will completely solve your problem, if phasing was the problem.

My suggestion though, buy a bass cabinet.
 
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#15
I had one a long time ago ..... cab was heavy, and the tone was just basically, dark sounding
3762226719_673e0c541e.jpg
 
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