If I put a 4 ohm speaker in would the amp object ? The factory speaker works but I am wondering if there is a speaker out that would sound better . When I play the low E on my bass the speaker sounds like it is out of its comfort zone .
Rumble 40 - It's only 40 watts and I would not recommend upgrading the speaker. 40 watts and a low E ringing out at moderate volumes is not what this is designed for. As for any other speaker upgrade, Talkbass has routinely taught me that the speaker chosen for a bass cabinet was chosen for a reason. There are specific size dimensions, air movement, and more involved with bass cabinets. If you don't like a particular bass rig, your best bet is to replace the speaker with something the manufacturer recommends or simply buy a different cabinet. Bass speaker swapping is not even close to the world of guitar speaker swapping.
In this combo, the amp and power supply are designed around the speaker impedance that the designer chose. IMO, it will be difficult to improve the performance without really understanding the designer’s intent. I know the designer, he’s more experienced than most of the opinions here on TB. The MB-150 is a very unique application because of the sealed and sub-compact nature of the enclosure. That’s a driver fairly unique to bass guitar, I wouldn’t expect any aftermarket swaps to work very well.
Read the fender rumble club wiki about speaker replacements. It'll tell you to install sound insulation in the cab first, the R40 and R100 don't come with it. It doesn't cost much and it works. Seems like you might fry the amp with a 4 ohm speaker, unless that's what is in there now.
Search TB. There is info about replacing it with an Eminence neo driver. So it has been done with success but the re-engineering needed is outside the skill set of most of us. And such a swap may trade one set of compromises for another. Whether it is an upgrade or not depends on what you are willing to give up for what you can gain.
First start with your tone controls. the baseline settings for flat are are seen here: Rumble Wiki Flat EQ for Rumble V3 40+ amps. After that then look into sound control materials inside the cab. Finally look into speaker upgrades and here. I did do a speaker swap in mine, but I had the speaker and it was described as what I was after in my R40. I only had to get the port tubes and cut and fit them. Following @AstroSonic's description, it was a perfect result for me. I used the Dayton Audio PA255-8 for my swap. Look into his other speaker descriptions for other styles.
Nice @MadJack - Yes, it was @AstroSonic's work that I was thinking of. And the Eminence S2010. Of course that speaker costs nearly the same as the whole Rumble 40 amp so the first compromise you're making when doing that swap is $$$. I almost bought the R 40 with plans to swap to an S2010 but in the end took the safer and easier approach of just buying a different combo which sounds good to me and needs not mods.
It’s a $200 40W amp that is packed with features for the cost, and sounds brilliant when used within the realm of common sense. A speaker “upgrade” is a waste of money. What you spend for the “improvement” you get just won’t add up. Its four e.q. knobs are quite capable. Learn to use them, stick to what it’s made for, and it will perform well. It’s a practice amp, recording amp, and does well for playing along with acoustic guitars, or when mic’d or DI’d for louder ensembles. Perhaps its greatest use is for playing along with records without making any noise, by combining use of the aux. input with use of the headphone jack. If you need more from it than it can provide alone, your best “upgrade” will simply be to run it in to a P.A….which it is equipped to do, right out of the box. If you want a Rumble that stands a chance on its own in an electric group and/or a group with drums, then you want the 200 at a minimum – preferably with the 1x15 extension cab to be added on when needed.
on average, this is the truth and the way to go. but, upgrading speakers is certainly possible and can be done with trial and error. The chances of an inexperienced person pairing a speaker to a box with great success is very, very low admittedly. there is simulation software that can determine if something is a match for your cabinet or not. When i needed a speaker i spoke with the nice folks over at usspeaker.com and they found a match for me. nonetheless the amps you describe i think would be a waste of your efforts if you are looking to replace the speakers.
The Rumble 40 is the best sounding low volume PRACTICE amp I've ever heard (once you know about where to set the bass knob and don't crank it) and the adage "If it aint broke don't fix it" applies. It's like when Teddy Rosevelt gave a speech at Yosemite National Park, he said we can't "improve this" natural wonder with development. Build you condo elsewhere.
I took some advice and insulated the interior with different types of sound foam . I did 4 of the six sides . The result is a sound that I can deal with . The speaker itself is a somewhat more robust device than I was expecting . Gee ,.. they could have sprung for a couple extra inches of speaker wire though .
It's very difficult to do better than the stock speaker without spending more than the amp cost (or is worth).
The low E-string notes take the most power supply energy to reproduce. You could be running out of headroom and into distortion. So it could be the amp more than the speaker, or a combination of both. It’s a budget amp, there are design limitations. It may not be able to deliver what you require.