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Blew my 12".....AGAIN!!!!!

#421
In the case of a biamping deal like this, your 2 cabs aren't sharing much bandwidth. A polarity reversal would only cause a null at and right around the crossover frequency. Beyond that, each cab will become dominant in its portion of the bandwidth. Though with a crossover at 100hz that could still cut a considerable amount of beef out of the sound.

Can try wiring the speaker both ways and pick whichever gives the fullest tone.

If you really want to hear that sort of destructive interference, you can pass a 100hz test tone (sinewave) through the system and switch the polarity of one speaker back and forth. It can be pretty revealing. There's a free phone app called TruTone that's easy to use. 1/8" to 1/4" adapter plug in the front of the amp and you're all set. Keep the volume low to start. :)
 
#422
In theory this is true Will, but I am a bit doubtful of the effectiveness of the biamping, and the symptoms described made me re-think some other possibilities including that the low pass output may not in fact be low pass by all pass. I'm just kind of dotting i's and crossing t's for thoroughness (in true engineer's fashion) ;)
 
#423
will33 said:
In the case of a biamping deal like this, your 2 cabs aren't sharing much bandwidth. A polarity reversal would only cause a null at and right around the crossover frequency. Beyond that, each cab will become dominant in its portion of the bandwidth. Though with a crossover at 100hz that could still cut a considerable amount of beef out of the sound.

Can try wiring the speaker both ways and pick whichever gives the fullest tone.

If you really want to hear that sort of destructive interference, you can pass a 100hz test tone (sinewave) through the system and switch the polarity of one speaker back and forth. It can be pretty revealing. There's a free phone app called TruTone that's easy to use. 1/8" to 1/4" adapter plug in the front of the amp and you're all set. Keep the volume low to start. :)
Click to expand...
I believe he isn't biamping now, dual full range mono
 
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#425
agedhorse said:
In theory this is true Will, but I am a bit doubtful of the effectiveness of the biamping, and the symptoms described made me re-think some other possibilities including that the low pass output may not in fact be low pass by all pass. I'm just kind of dotting i's and crossing t's for thoroughness (in true engineer's fashion) ;)
Click to expand...


Well, I admit, I skipped the last 6 or 7 pages. After having spent a good deal of time reading through the first 13 the other day, and now checking in to see it up to 21 or 22, I thought we'd have found the problem by now, haha. :)

I used to have an older Carvin head, not the newest model this guy has, but his looks to be laid out the same way. You could do true biamping, or you could send the fullrange signal to both channels yet still control their volumes independently, just like a PA type poweramp, but you could Not high or low pass one channel while all-passing the other. Also there was no polarity switch on the amp.
 
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#426
Note that my comment about biamping is a general comment and not about that amp in particular. I recall that there were other approaches the OP attempted to biamp as well.
 
#427
For what it's worth, my (many years old now, Eminence built) Avatar OEM 12's, built on the Deltalite structure, move outward with positive voltage applied to the positive (red) terminal, but that really doesn't mean anything. Designs could've changed over the years or a simple miswire in a cabinet or a particular speaker cable would render that point moot.
 
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#428
agedhorse said:
Note that my comment about biamping is a general comment and not about that amp in particular. I recall that there were other approaches the OP attempted to biamp as well.
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People on here also seem to have a few different definitions of what "biamping" Is. :)

In the OP's case, with the crossover that low, he probably needs all four 8's to get a full lowmid/upper bass tone happening at gig levels, but IMO there just Isn't a single 12 that can hang with that. Raise the crossover point 2 or 3 octaves and then you only need a single 8 to balance with a 12, or possibly 2 withan LF specific woofer you could put some power to and move air cleanly.

The OP said earlier he likes taking the 12 alone for small stuff so that rules out LF specific woofers or true subs.


Maybe I should go back and pick up where I left off. Find out what's really going on before we blow speaker number 6.
 
#429
I can't wait to hear about the speaker polarity. I'm hoping to hear he polarity was reversed and they now sound better together.

But I also agree that a single full range 12 probably wouldn't work with that 4x8 as a sub at volume. If both cabs run full range work well it will add volume and color and may be a solution.

Hoping the OP reports back.
 
#435
Because he was having to drive it way too hard to get enough volume like that. Ears are a lot more sensitive to mids and highs, so when you have lots of mids, you're not as likely to turn up as much. Meanwhile, he had plenty of mids from the 4x8, so he was trying to match just the lowest frequencies using the 12, thus pushing it way too hard.
 
#436
Ok guys.... Checked both the ampeg 4x8, and the avatar b112 and they are both wired correctly. All drivers go out when tested. Alone, and in series.

I think the reason I like the sound of the avatar alone better than the pair in Byam or full range is that the avatar simply sounds better with the new LFC driver. As a full range cabinet I mean.
 
#437
Are you running your (dissimilar) cabinets in SERIES???

If so, we may have inadvertently discovered the real problem.
 
#440
tzohn said:
Sorry guys still not clear to me, why if avatar 12" cab was driven full range would not have been blown but
in the range <100Hz is blowing up. What do I miss?
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Omega Monkey said:
Because he was having to drive it way too hard to get enough volume like that. Ears are a lot more sensitive to mids and highs, so when you have lots of mids, you're not as likely to turn up as much. Meanwhile, he had plenty of mids from the 4x8, so he was trying to match just the lowest frequencies using the 12, thus pushing it way too hard.
Click to expand...
that's WHY the 12 blows. It will STILL blow being run fuller range. As explained multiple times already, that adds more power into the 12.
 

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