I just saw the specs of the 12" speaker in the Fender Rumble 100, and now I’m not sure I want this amp.
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In regards to PJB, I recently saw this:
and
Looks like something available only in Japan. It is not even mentioned on PJB website.
It has Bluetooth and can be powered from battery via USB C.
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Interesting, I do think no bluetooth was a mistake on the US ones.
Maybe it is coming and not here yet (and why it’s blue)
FWIW - I tried out the nano cube when I was shopping - it just isn’t there, more of a better tiny practice amp.
The Double 4 and Cubs can hold their own at a jam or practice I’d imagine and why i originally bought the cub-120, but have it hooked up by my desk for keyboard, drum pad, guitar or bass.
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Very very interesting. Pmax of 75 so it’s unlikely you’re actually getting more than 50-60 out of the thing; the resonant frequency at 48.1 might be a problem too. The SPL is actually quite low as well, or sounds very low to me for a speaker in a 100W amp. Not really familiar with the other measurements though.
Is that Pmax sustained or peak?
It actually seems like a repurposed guitar amp speaker? I guess that’s not surprising.
Dunno. Probably a limited edition colour.
But on this site there are all regular colours as well:
Yeah, a lot of problems with this speaker. I’m wondering if it’s the right speaker specs actually.
Pmax of 75 and a SPL of 92.6 , that’s really really bad.
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Agree! That really reads like a 4-6" speaker. SPL of 92.6 is not loud at all. My monitors (5") have a continuous SPL of 94 each.
Invoking @DaveT who seems to always be able to track down info like this from some magical repository of data no one else can find 
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yeah 
here is the link where I found this datasheet : https://www.talkbass.com/threads/fender-rumble-v3-100-speaker-up-grade.1247486/
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It looks like the Beta-12 specs they posted will be over triple the apparent volume of that one 
It has a resonant frequency in the 47Hz range too. That seems… bad. That’s literally right between F#1 and G1. Second and third frets on the E string. You don’t want your cab resonating there.
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dammit, i like this even more than the x4 nano i just bought.
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yep that’s exactly what it is. that being said, if that’s what you’re looking for it’s pretty killer.
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Hee hee. The collection of repositories is the result of having one career topic for 35 years.
The Thiele-Small parameters are openly published by the OEM driver manufacturers. Here is one example:
These don’t necessarily apply to a driver in a manufacturers finished cabinet. It’s possible that a manufacturer may go back to the OEM driver supplier and request modifications to the base design or specs for a particular product run.
The Thiele-Small parameters are complicated and are pretty much unusable unless one is deeply knowledgeable in cabinet design. Substituting a driver into an existing cabinet design would be pretty tricky to get right.
A driver expects to be inserted into a cabinet with a particular volume of air to achieve optimum performance. The actual cabinet design may or may not have that volume of air. A substitute driver that likes a different volume of air will behave differently in the cabinet it’s being substituted into if it doesn’t have the same parameter as the one that’s being taken out.
Power handling is extremely complicated since drivers fail for different reasons. I don’t really know, but I suspect Pmax is the maximum average power the driver can take over some period of time before it suffers thermal failure. Can an amp rated at 100W really provide a sustained average of 100W with a much higher peak power or is the amp power rating skewed more toward the peak than the average? It could be that a 100W amp is generating 25W average during actual playing and wouldn’t overheat an 80W max average driver, for example.
Max Peak power is usually governed by the maximum excursion distance before the driver pops out of its socket and never goes back. This will be a voltage based relationship, so the power number will change based on impedance. And the impedance is not the same across the operating range of the driver. They just tell you a “nominal” impedance on the cabinet spec, but it swings quite a bit depending on frequency. A driver resonance occurs where it has its lowest impedance (it moves the most where it resists the least).
“Resonance” in this context has different significance than when we talk about a room resonance or a cabinet resonance. Resonances in finished products are usually bad things because they represent unwanted peaks. In raw driver terminology, resonances are where the device works the strongest and we are going to get the most performance out of it. Crossover circuits and manufacturer tunings get sculpted around the resonance of a driver to even it out and make it musical. This is another reason it’s difficult to substitute a driver in an existing cabinet. Chances are it’s tuned to compensate for the driver that was in there to begin with.
I suspect people who change out drivers to get a better result are getting a peak and a dip where they happen to like it and this would be very personal. I’d bet everyone else’s mileage will vary wildly. Cabinets are designed to be complete systems and are interactive between design elements. But just like strings and bridges and everything else, there’s nothing wrong with tinkering and seeing what results you get if it’s what you’re into.
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And if any of the woodworkers wanted to build their own bass cabinet, the driver manufacturers all have reference designs and measurements available.
At Eminence you can click on “Specifications” and then “Cab Design” . .
They will give a stack of example cabinets with their predictive simulation stats. I’ve never built one because of how much work it is to get all the cabinet bracing and stiffening right so the sides don’t flex. But if one had a shop and did it all the time it could be interesting.
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Not only interesting, but confirms I never want to build a bass cabinet.
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I would love to build one
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I’m not really smart enough to understand what @DaveT thoughtfully posted; my only take away is that @terb trash talked my Rumble 100 
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I think what @DaveT said is:
A: Depends - too many factors to consider to say it’s crap.
Then he said a bunch of super interesting stuff that has taken the place of things I actually need in my brain, which I will promptly forget most of.
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Sorry, it was not the point. I really liked the Rumble 100 and considered buying one, but the speaker would need to be changed : the SPL at 92.6 db/w/m is a big NO-NO for me. I’m not saying that the amp does not sound good. It would most probably be a bomb with a proper speaker swap.
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