One head, 2 cabs = One cab MUCH louder than the other, why?

[SLO Surfer]

Set the amp to 2ohms even if the cabs are only daisy chained?

YES!!!! the load is the same and can damage your amp if you are trying to run a 2ohm load on a 4ohm amp.

 

[Maynjo]

Confusion. First of all you're asking why a 6x12 is louder than a 4x10, then you posted a picture of a 6x10 and a 4x12.....

Edit: Nevermind I saw the correction. I would assume the 610 would be louder than the 412, or very close to the same volume.. maybe you're experiencing some type of phase cancellation? Are they both 4 ohm cabinets?

 

[Old Garage-Bander]

Just for interest what are the impedances of the two cabinets?

+1 on this thought.
Make sure you know the cab impedances before you decide there might be a real problem.

An 8 Ohm 4 Ohm split would be 2/3 power to the 4 Ohm and 1/3 power to the 8 Ohm.
And yet power to a cab, when they are not the same type of cabs offers no assurance of anything either.
This is because there are other factors involved like sensitivity and SPL that can vary greatly between speakers and cabs.

Also be sure the cabs are in phase. A six by, out of phase with four by, might end up sounding like a 2 by.
And to make matters worse, this does not take into account other cancellations that might happen even if they are in phase.

Until you know more about the gear, you are comparing apples to chickens. Not even close enough for a bad guess.

 

[PotsdamBass8]

I apologize if this has already been said, but I got to page 2 and didn't see it. If you like the sound, and just need to balance the level of the two cabs together, AND have another head you can use, I would run one head to each cab but run the FX loop out of the Mesa into the FX return of the other head. That way you have one EQ section that controls both, but the master volume on each head is only controlling one cab each. Then you can balance as you see fit. Doesn't cost anything more than a cable or two, as long as I read correctly that you have two heads already.

 

[Old Garage-Bander]

Set the amp to 2ohms even if the cabs are only daisy chained?

There is nothing special about daisy chaining. Daisy chain is one form of parallel, but is not electrically any different than any other form of parallel. All parallel connected devices are parallel. "Only" does not apply here in the sense that the impedances of multiple connected cabs being any different because of being daisy chained.

 

[Old Garage-Bander]

Haha. RTFM. Very rare around here.

There will be plenty of time to read the manual when the amp is in the shop.

 

[bebass]

Any recommendations for a good "splitter" pedal for running two separate rigs with one bass?

I didn't read the whole thread so this may have already been answered and suggested.

Even though I would not personally try this due to cancellations and it being a nightmare to EQ, the answer is to just use an AB/Y box to two amps. Then you can EQ each cab separately and level the volume of each setup. I suggest an isolated AB/Y box instead of just the simple AB/Y box.

I used to use two separate preamps to two different amp sections into two different speakers and in some rooms it was amazing and in other rooms, due to acoustic response....it was a problem that I created. I have since found out I prefer to keep it simple and use one brand of cabs with a single amp and it is so much easier and sounds better to me.

 

[HolmeBass]

I looked at the photo - for starters, it's a 610 vs a 412, not as OP wrote it down.

The post suggesting "sensitivity" is spot on.

The other possible issue could be if one cabinet has a lower impedance than the other one - the one with the lower impedance will get more wattage and thus also be louder.

But honestly, sensitivity differences could easily overcome the wattage difference. A 4 Ohm cabinet will get 2/3 of the amps output power when paired with an 8 Ohm cab, which get the remaining 1/3. So the 4 Ohm gets twice the wattage, which is only about +3 dB. If the sensitivity difference between them is such that the higher impedance cab's sensitivity is >3 dB higher than the lower impedance cab's, then the higher impedance cab could still end up louder.

 

[tjh]

… I am starting to wonder …






what small % of folk reads a thread before replying

 

[David Sutkin]

Thanks to all those who gave me some really great information on this thread. I learned some important things about amplification that I had previously been unaware of and many of you really saved me some future nightmares.

 

[ktedrow]

To the OP, you can edit your original post to fix the 4x10 vs 6x12 error.

 

[David Sutkin]

I did that earlier.

 

[Old Garage-Bander]

… I am starting to wonder …






what small % of folk reads a thread before replying

Sounds like a good subject for a TB Poll.

Before replying to a thread, I read [answer A][answer B].

Answer A
All the posts
Most of the posts
Half of the posts
Some of the post
Only the first post
Only the last post
Just the title
None of the posts
About Carrots

Answer B
All of the time
Most of the time
Half of the time
Some of the time
Never or Ever
-blank-
When it's the best answer for Metal

 

[ktedrow]

I did that earlier.

Great. Sorry I missed that.

Interesting problem you have. The speaker area of the 2 cabs is similar. Impedance also. So both are getting the same power, so I'm surprised the volumes are so different.

Looking at the GK website I see that that cab has a horn. Could that explain things?

Also, because the GK is taller more volume is directed at your head. Have you tried lowering your head when comparing volumes?

 

[David Sutkin]

Great. Sorry I missed that.

Interesting problem you have. The speaker area of the 2 cabs is similar. Impedance also. So both are getting the same power, so I'm surprised the volumes are so different.

Looking at the GK website I see that that cab has a horn. Could that explain things?

Also, because the GK is taller more volume is directed at your head. Have you tried lowering your head when comparing volumes?

Thanks for the post ... the volume levels are so extreme that I don't think the heights of the cabs are the issue.

I mistakenly did not switch the amp head to 2 ohms so next time I'm in the rehearsal spot I'm going to see if that makes a difference.

I've also purchased one of those splitters that was mentioned earlier in the thread as highly recommend

I own a few different amps and I've decided to just run them both and play out of two separate rigs moving forward.

 

[Lowendtech]

the volume levels are so extreme

In a rehearsal space? Are you wearing earplugs with this setup in said room?

 

[David Sutkin]

"Extreme" as in the difference between the 2 cabinets ... not the overall volume being extreme

 

[dbsfgyd1]

Hey all,

I was hoping I could get some help trying to understand why the following is happening.

Last night at a band rehearsal I tried running my Mesa D800+ head into a Mesa 6x10 "traditional" cabinet (900 watt cab) then I ran a speaker cable out of the Mesa parallel jack port into a GK 4x12 cabinet (1000 watt cab) ... The one Mesa head powering both.

While I was absolutely pushing air out of both cabinets, the GK was shockingly louder than the Mesa cab ... If I had to guess, it sounded like a 75/25 volume output ratio with the 75% coming from the GK cab.

I used to have a Hartke LH1000 head that came with a "leveling" dial and I could manually turn that dial to blend the two volumes but the Mesa D800+ head doesn't have that feature.

Can anyone give me some insight (in layman terms please) as to why the GK cab is pumping such a drastically louder volume?

Is there a better way to run this set up? I have a few other heads and I wouldn't mind buying an ABY splitter and running two separate rigs (1 cab with one head and another cab with another head) to level out the volumes .... but do I need to do that to get the volume levels equal?

Any help would be great, thanks

View attachment 3101703

Cab efficiency, ohmage, speaker area, and speaker extrusion all come into play here. I will say the most likely things are cabinet efficiency and ohmage. There is a big difference between a cab .97% efficient and 103% efficient with regard to the amount of decibels they will produce.

Ohmage is another issue, and 8 ohm cab will not be a loud as a 4 ohm cab, because the 4 ohm cab will be receiving more power from the amp.

Some of our mighty fine engineering crew should be along shortly to explain these things in detail.

 

[agedhorse]

Could it be the Mesa cabinet put out considerably less volume because I didn't switch the amp to 2 ohms prior to plugging in the 2nd cabinet?

No, this won't make any difference between the volume of each cabinet relative to each other.

I think you really need to have your cabinet checked out, I am pretty sure something is wrong with your 610 (maybe a bad driver, maybe an open connection to one pair of drivers, reversed polarity to one driver in a pair, etc.

It won't make any difference running one or two amps, this is a solution for a problem that is not the problem you need to solve. It's just a wild goose chase at this point and might lead to damaging the cabinet more by driving it even harder.

 

[fermata]

I suppose I can't quite fathom a situation that needs the speaker area of 610+412 cabs. A 610 or a 412 on its own can move a significant amount of air. Normally, when discussing multiple cabs, the idea is to expand on a smaller platform...like pairing a second 210 with an existing 210. In other words, either the 610 or 412 alone is already as big as or bigger than most multiple cab setups people are using.