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Help! I don't know what's wrong with my rig!

Joel Schirripa

Joel Schirripa

Guest
Dec 21, 2013
37
1
#1
So recently I made a bass cabinet fitted with an eminence delta 12" and an eminence delta 8". I use an old (from the 70's) Fender PA100 head (all tube). My problem is that when I turn the channel volume to 10 and then the master to 4+ and play I get so much shaking and farting and it just sounds terrible. I don't know whether it's the fact that the head was never designed for bass or if it is that my cabinet wasn't made as well as it should have been and it is shaking itself creating that buzzing/farting sound. Please help, I know everything is okay wattage and ohms wise but I just need some advise, the cabinet wasn't easy to build and I don't want to go through it again, please just give me some advice. I can't tell whether the cab is shaking or everything loose in my room is? I know that when I use other bass amps at school and stuff that they shake heaps and the snare usually rattles but this is very different.
 
#7
Joel Schirripa said:
Please help
Click to expand...

OK, troubleshooting involves replacement of the device under test by a known good substitute. Try another amp through your cab and tell us what you get. Also try reversing your Fender's gain settings, Master higher and Gain lower.

As far as cab design, the two drivers are in separate sub-chambers with suitable damping, right?
 
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#8
Passinwind said:
OK, troubleshooting involved replacement of the device under test by a known good substitute. Try another amp through your cab and tell us what you get. Also try reversing your Fender's gain settings, Master higher and Gain lower.

As far as cab design, the two drivers are in separate sub-chambers with suitable damping, right?
Click to expand...

I have tried having the master higher than the channel. When the master is at 3 and the channel at 10 it is louder than master at ten and channel at 3. as for separate compartments I did not know I had to do that, I watched a bunch of videos on youtube of guys building guitar cabs and I had a good look at my dad's custom 4x12. I don't think I realised that guitar and bass cabs are so different. I didn't put any wadding in anyway. if that is a big problem.
 
#10
Joel Schirripa said:
I don't have a tweeter, if I need a crossover still just explain what I need it for...
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The Delta 8 is a midrange driver, not a woofer. You need to keep deep lows away from it for cleanest results. It should work quite well if you do that though.
 
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#11
You've watched a lot of guitar cab builds but not bass cab builds. They're not the same. Nowhere close. ;)
You've also got a mid-speaker and a woofer. A crossover takes the signal and sends the lows to the woofer and the mids to the mid speaker. A small mid doesn't like to have a lot of bass fed to it. They tend to vomit out their innards.
 
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#14
BurningSkies said:
You've watched a lot of guitar cab builds but not bass cab builds. They're not the same. Nowhere close. ;)
You've also got a mid-speaker and a woofer. A crossover takes the signal and sends the lows to the woofer and the mids to the mid speaker. A small mid doesn't like to have a lot of bass fed to it. They tend to vomit out their innards.
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That must be where that buzzing sound it coming from. It must not be able to handle my low E very well. How can I get a cross-over? Can I order one on ebay and simply install it? I would like to say thanks anyway for all your advice
 
#17
Joel, you've not done any engineering for this cabinet. That would involve a bunch of math that you may not have studied yet. If you check out Greenboy's site, you'll find that he's already done the engineering. Unfortunately, Greenboy's or any other pre-engineered cabinet designs, may not be intended for the speakers you already have.

As far as the crossover goes. It's not a case of one size fits all. You would need to get a crossover that's the right frequency for your speakers.

Raf
 
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#19
BurningSkies said:
Did you follow Eminence's suggestions on the box size and/or porting? I don't know which "Delta 12" you have, but they have fact sheets up with suggested cabinet sizes and porting.

http://www.eminence.com/?s=delta&x=0&y=0
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I have the Delta-12B the 16ohm woofer. I think my current cab is as good as a guitar box but if I were to build two new cabs with appropriate specifications and wadding making the speakers separate from each other would that work well? I do really like the speakers I bought, they do sound nice, I would like to use them together in the near future.
 

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