4 ohm / 8 ohm Head, 2 - 8 ohm cabinets

[Moordoom]

I have a Crate BX220h Bass Amp Head that is a 4/8 ohm head.
I am looking at replacing my blown 1x15 4 ohm cabinet with 2 Seismic Audio 8 Ohm cabinets.
One is a 4x10 with a horn, the other is a 1x15.

My head is 220 watts at 4 ohms, and 150 watts at 8 ohms.

If I plug in the two 8 ohms Cabinets into the two 1/4 jacks, Crate documentation says I am at 4 Ohms total impedance.
I know Daisy Chaining them and plugging them into one jack only would put me at 16 Ohms.

So looking at this doc, with the two prospective cabinets, will I be at 4 or 8 ohms, and 220 or 150 watts?

Sorry to beat the Old Dead Ohms Horse again. I saw a document/post on here a few months back that covered the "ohms" issue but could not find it in my search.

Crate BX220h

• Moordoom
• Aug 4, 2016
• bass amp bass amp head

Ohms

 

[Jim Carr]

....If I plug in the two 8 ohms Cabinets into the two 1/4 jacks, Crate documentation says I am at 4 Ohms total impedance.

Correct.

I know Daisy Chaining them and plugging them into one jack only would put me at 16 Ohms.

No. The 2 1/4" jacks and daisy chaining are all the same thing, and hence yield 4 ohms load with 2 8 ohm cabinets.

OHMS FAQ: Ohms FAQ

 

[Jim Carr]

Furthermore, I'd get 2 identical 8 ohm cabs instead of a 410/115 rig. Yes, it works, but the 115 will very probably fart out before the 410.

BTW, contrary to conventional wisdom, 15" speakers don't "go lower" per se than 12" or 10" speakers. It is down to the individual driver's design and the cabinet's suitability to the application as to how well a speaker/cab can deliver lowend.

 

[ThisBass]

Yes, it works, but the 115 will very probably fart out before the 410.

see OP's first post

"My head is 220 watts at 4 ohms, and 150 watts at 8 ohms."

which means 110 watt power pusehd into one cab if both cabs are of 8 Ohm impedeance.

Must be a really crappy cap that will fart out on 110 watt system input power.

 

[Moordoom]

Not so much crappy, as its a 30 year old paper cone speaker in it. Just wore out and dry rotted.

 

[Jim Carr]

see OP's first post

"My head is 220 watts at 4 ohms, and 150 watts at 8 ohms."

which means 110 watt power pusehd into one cab if both cabs are of 8 Ohm impedeance.
Must be a really crappy cap that will fart out on 110 watt system input power.

Of course he will keep that head forever, right?

 

[two fingers]

Yeah I'm gonna go ahead and jump in too.

Get two matchng cabs. It simply works beyyer most of the time. Honestly I would get the 15s but that's just me. @Jim Carr is dead on. You will NOT get "more lows" from a 15" and "more mids and highs" from a 4-10 just because of driver size. In fact, many 4-10 cabs are more boomy than some 15 cabs I have owned.
It MIGHT sound fine with one of each. But it WILL sound fine with two matching cabs. It all depends on whether or not they were DESIGNED to work together as a pair. Folks like @agedhorse can clear that up if need be. But not all 15" and 10" cabs are designed to compliment each other and be used in the same system. Some are. But they are more rare in my view.

We're just trying to help. At the very least, if you go with the two different cabs, put the 15" on top so you can hear it gasping for air when the tone comes.

 

[ThisBass]

Buying an unknown cab without testing is a crapshoot anyway cause not every cab-system will be everybodys cup of tea, either way the cabs do match or not. So it's always a good idea to do a test before spend the dollars.
Sometimes a desired sound goal can be reached just by the mixing of different cabs (voicings).

 

[BadExample]

Same model cabs are your best bet. Unless you know and understand the impedance curves of all cabs in use, the odds are they will cancel certain frequencies where there is an impedance mismatch. In fact, if I may be so bold, I'd say the odds are very slim that you wouldn't get some cancellation of frequencies at the peaks of the impedance curves (to be safe, dawning my asbestos flame suit now). Murphy's law will cause those cancelations to be at the worst possible frequency for you tone goal. No disrespect intended to @murphy

In your OP you mentioned daisy chaining and that the impedance (Z) of the cabs would add together. Just FYI, this is not true. The formula is to add together as 1/cabZ + 1/cabZ +1/cabZ... = 1/totalZ. Easier with a calculator or google up a parallel resistance calculator online. Easy with a calculator with a "1/x" button. Just enter the ohms (the Z) of cab 1, press "1/x" button and plus, repeat for all cabs, then press = then press "1/x" button again for an answer. Easier to do than explain and it's just as easy to google a parallel resistance calculator online. I'm just telling you this so you don't inadvertently plug an insane low Z load into your amp one day if you daisy chain several cabs in the future. I like this one. A bit complicated looking, but versatile. Rows are speakers in series, and columns are parallel speakers. Shavano Music Online - Speaker Wiring; Impedance Calculator

Best of luck with your project!

 

[Moordoom]

Of course he will keep that head forever, right?

Yes, I plan to keep the head forever. Its a 1988 Serial number, and has not given the first bit of trouble.

It all depends on whether or not they were DESIGNED to work together as a pair. Folks like @agedhorse can clear that up if need be. But not all 15" and 10" cabs are designed to compliment each other and be used in the same system. Some are. But they are more rare in my view.

What I am looking at is this:
4x10 Bass Guitar Cabinet with Horn | 410 Bass Cab loaded with Horn | 115 Bass Cab| 115 Bass Cab
They have good reviews, a friend has the same cabs, but with an Orange Terror 500 head, And the sound was Awesome.
I played my Fender American P Bass through it, So I did "test" them somewhat.
Not sure if they are designed to go together, or just clumped in together as a package deal.

I play mostly small venues, so looking for just low price setup, that doesn't sound like an amped up car radio.

 

[two fingers]

Yes, I plan to keep the head forever. Its a 1988 Serial number, and has not given the first bit of trouble.


What I am looking at is this:
4x10 Bass Guitar Cabinet with Horn | 410 Bass Cab loaded with Horn | 115 Bass Cab| 115 Bass Cab
They have good reviews, a friend has the same cabs, but with an Orange Terror 500 head, And the sound was Awesome.
I played my Fender American P Bass through it, So I did "test" them somewhat.
Not sure if they are designed to go together, or just clumped in together as a package deal.

I play mostly small venues, so looking for just low price setup, that doesn't sound like an amped up car radio.

If you have heard them together and they sound great, go for it. I wasn't trying to talk you out of it per say. Just warning of the possibility that it may not work out. Glad it does and you dig it.

That being said, whenever you divide power into two cabs like that, understand that the ONE 15" is getting the same amount of power that is divided by FOUR among the 10" speakers in the other cab. A 15" speaker isn't necessarily more "robust" than a 10" speaker. So please put that 15" on top so you can hear potential problems presenting themselves if you push it too hard.

Hope you like your new setup.

 

[basscooker]

Even a good quality, well built 400 watt 15 can hit excursion limits with 110 watts of power if the tone shaping controls are set to extremes. Power ratings do not tell you anything about low end extension limitations. The voice coil will survive the hypothetically 110 watts, but the cone may not. The same 110 watts divided by four would most likely be safe with nearly any settings, if the OP were to use a pair of 410's.

 

[BadExample]

Yes, I plan to keep the head forever. Its a 1988 Serial number, and has not given the first bit of trouble.


What I am looking at is this:
4x10 Bass Guitar Cabinet with Horn | 410 Bass Cab loaded with Horn | 115 Bass Cab| 115 Bass Cab
They have good reviews, a friend has the same cabs, but with an Orange Terror 500 head, And the sound was Awesome.
I played my Fender American P Bass through it, So I did "test" them somewhat.
Not sure if they are designed to go together, or just clumped in together as a package deal.

I play mostly small venues, so looking for just low price setup, that doesn't sound like an amped up car radio.

Those look like a bargain if the build quality is good. Please let us know how they sound to you.

 

[Jim Carr]

Yes, I plan to keep the head forever. Its a 1988 Serial number, and has not given the first bit of trouble...

...I play mostly small venues, so looking for just low price setup, that doesn't sound like an amped up car radio.

No doubt you will keep your BX220h "forever." However, IME sometimes one needs more power. Having ANOTHER head to use in that situation could possibly be advantageous.