Cab output power exceeds amp output capacity

[foldy]

I've been reading a lot of topics on this forum for the past few days, getting a lot of info. But was not able to find any topic on the following, which I hope some of u know an anwser to:

I have the following gear:

Markbass CMB 121P combo (8 Ohms)
it has a one 12" speaker in it and a head with an output power of 500W @ 4 ohms and 300W @ 8 ohms (which it uses atm I think)
see this link for a complete overview of the technical specs:
Markbass - Mini CMD 121P

Expansion
I was looking for ways to expand this little amp. Since I've been pleased with the sound and mobility of my current Markbass combo amp.
I came across the Markbass standard series. For example the Markbass STD 104HF (8 Ohms) going at 800W, four 10" speakers.
For all the technical specs: http://http://www.markbass.it/product_detail.php?id=33

Questions
So technically two 8 Ohms speakers creating 4 Ohms when combined should not be a problem.
Since markbass states all their head amps should not go below 4 Ohms.

Which leads me to the following questions:
1. Will it blend? :P in other words, will a 121P combo and 104HF speaker go hand in hand? (markbass website states it is possible to connect them together, but will this actually improve my sound?)
in terms of a 1x12" and 4x10" speakers combined together.
2. A head stating an output power of 500W @ 4Ohms: does this mean getting an 800W cab with the combo amp won't go along side of eachother since the head only has a capacity of 500W?

I'm thinking of trying this combination at a store in a month but thought it would be useful to do some research too.

It would save me some real money if I could buy a new cab instead of having to buy a seperate head and cab.


thanks in advance!

[Joe Louvar]

Markbass says the “New York 121” is the perfect companion for the Mini CMD 121P.
Markbass - New York 121

[scottfeldstein]

Short version:

1. Get a single 12" speaker cab to expand your 12" combo.

2. Forget the fact that speaker cabs even have a watt rating. It's irrelevant.


Longer version:

It's tempting to hook up a big powerhouse of an extension cab to your itty bitty combo. And you can. It will work--sort of. The problem is that you won't be able to turn the volume knob up as high as the big cab can handle. If you did, you'd be blowing the speaker in the combo because it also has to handle whatever you're throwing at the big cab. Get it? It's like me and a body builder each picking up one end of a heavy barbell. It doesn't matter how strong he is. You still can't put on more weight than I can lift.

So basically you'd have the expense, size and weight issues of a big cab but only a small fraction of its volume benefit. Generally not worth it. This is one of the reasons why knowledgeable TBers often counsel people not to mix cabinets (which is essentially what you're proposing).

Also, forget about speaker cab watt ratings. It's a limit that the speaker coils have, but the cones will exceed maximum excursion far before that watt limit is reached. Just because a cab is rated at 800w or whatever, doesn't mean you're ever going to push 800w to it. If you tried, you'd realize your mistake at about 400w. The cones will start farting and tearing themselves apart long before the voice coils overheat.

[Electricblue]

A 410 with a 115 is very dodgy, let alone a 112.

The 12" is only a tiny bit bigger than a 10" that will be in your 410. They will probably have the same size voice coil!

It's not a good idea. But unplug the 12" and you will have a nice experience with the 410.

[coreyfyfe]

2. A head stating an output power of 500W @ 4Ohms: does this mean getting an 800W cab with the combo amp won't go along side of eachother since the head only has a capacity of 500W?

I'd suggest reading the FAQ stickies at the top to get a better handle on how to understand power ratings and such. Your amp will output x amount of power at y impedance, but that has little to nothing to do with the wattage rating of the cab. As said above, the wattage rating of the cab only refers to the electrical/thermal handling capabilities of the speaker's voice coil, and most speakers will reach their mechanical limits (excursion) before you damage the voice coil.

[dmusic148]

Originally Posted by Electricblue

A 410 with a 115 is very dodgy, let alone a 112.

The 12" is only a tiny bit bigger than a 10" that will be in your 410. They will probably have the same size voice coil!

It's not a good idea. But unplug the 12" and you will have a nice experience with the 410.

This.

[foldy]

Thanks alot for your quick and informative responses. I can see all of your replies share somewhat the same conclusion. This was the exact info I was looking for and I've come to the conclusion I'd have to sell my combo and get a separate head and cab if I'd like to expand my gear. Again all of your help is deeply appreciated!

[scottfeldstein]

I myself went through this process a few months ago. I had a GK 210 combo. Agonized over how to expand it. Eventually listened to reason and got a matching 210 cab to go with it. THEN realized that a pair of 210 cabs weren't gonna cut it for me, so I sold the entire rig and went with a separate head/cab scenario as I should have done in the first place. The entire misadventure didn't actually end up costing me much, though. I bought the amp on sale and got a good price when I resold it. I'd say all things considered I was probably out less than $150 on the whole thing.

[foldy]

Originally Posted by scottfeldstein

I myself went through this process a few months ago. I had a GK 210 combo. Agonized over how to expand it. Eventually listened to reason and got a matching 210 cab to go with it. THEN realized that a pair of 210 cabs weren't gonna cut it for me, so I sold the entire rig and went with a separate head/cab scenario as I should have done in the first place. The entire misadventure didn't actually end up costing me much, though. I bought the amp on sale and got a good price when I resold it. I'd say all things considered I was probably out less than $150 on the whole thing.

So I think that should leave me to just one choice, learn from your experience and do what I have to do, find a good head and cab I like. Actually looking forward to it.

[scottfeldstein]

Ironically, I ended up buying just about the exact same amp, just in a separate head: the GK MB500. I liked the amp, saw no need to change it. I just needed to ditch the attached speaker cab.

I felt very, very torn between having a really loud rig (I am playing with some really loud guys right now) and having something that my 43-year-old-ass can actually move around and fit in my little car. I decided to get a pair of GK Neo 212 cabs. But halfway on that journey, with only one of them bought, I became broke and so I punted and got a used 410MBX cab on the cheap.

I know, I know. Mismatched cabs. I know as well as anyone what the downside is. I haven't actually used them together yet. The 212 is here at home (doing nothing mostly) while the 410 is at rehearsal where I use it with the band. We're just getting off the ground so there's no gigs yet. I imagine I'll try them together at that time.

[Joe Louvar]

Originally Posted by foldy

So I think that should leave me to just one choice, learn from your experience and do what I have to do, find a good head and cab I like. Actually looking forward to it.

If you liked the Markbass Mini CMD 121P you might like the Little Mark III.

Markbass - Little Mark III

[foldy]

@scottfelfstein
Hehe I think i will end up with kind of the same head too. But just with a more badass cabinet under it. I'll be saving money to get the whole package all at once

@ joe louvar
I figured that was pretty much the same head which is in my combo atm. Thanks for your advice!

[Russell L]

You can add a Traveler 121H cab to your combo. It will have more bottom than a NY 121 due to its bigger box.

Me, I have a CMD 121H combo, but I've since gotten a LMIII head and a Traveler 151P cab (single 15"). I plan on another 151P cab. The 15 seems to handle more than the 12 did.

[scottfeldstein]

Originally Posted by foldy

@scottfelfstein
Hehe I think i will end up with kind of the same head too. But just with a more badass cabinet under it. I'll be saving money to get the whole package all at once

Love this head. My only regret is that I didn't pony up the extra money for the tube preamp version, the MB Fusion. I probably would have forgone the overdrive pedal on my board, had I done so. C'est la vie.