NAD - Fender Rumble V3 100

[at77]

Hey Rumble 100 V3 fans - a mutual fan here. I also use it for jazz guitar, and it's fantastic, by the way! I've played just a couple upright bass gigs with it and it's been great.

Another mod to add to the list that helps out.... flared ports are supposed to offer cleaner low end (possibly cleaner overall sound) especially at louder volumes, and sometimes provide greater output overall. From my experience with this mod, I'd say that's true. Prior to this, I had stuffed my ports with foam because I didn't like the sound with the stock ports.

I swapped out the straight cardboard ports for PVC flared ones and then smoothed the front edges too (putting the flares pointing inside the box). Cost a total of $8 plus 50 cents worth of glue, and took about an hour.

I used the ones linked below from parts express and they lower the tuning a bit (installed, they are 'effectively' 1/2" longer than stock, approximately - they measure 3" long, but you calculate only 2.5" length, so you get a total of 2.75" compared to the stock 2.25"). The slightly lower tuning seemingly smooths out that bump in the low end around 100hz a little bit and seems to give it clearer low extension. Conveniently, they fit perfectly in place of the cardboard ones as far as the hole goes. But I did trim about 1/8" off of one 'side' of each flare to give a bit of room from the box rather than having them rub up against it, which i figured could possibly cause rattles (maybe not). I also kept my insulation an inch or so away from the openings of the ports so as not to interfere with the airflow and tuning.

These are the flares I used, but I bought mine in Canada from solen.ca
"Precision Port PSP-3IF 3" Inside Flare for Port Tube" from www.parts-express.com!

To get the cardboard ports out, I scored the glue inside with a knife (as much as I could reach anyway) and then just squeezed the tube firmly but slowly, working my around the whole thing, to separate it from the plywood with as little tearing of the plywood as possible.

I used a "Pit Crew" adhesive to hold the new ones in place because it was the best option on hand. Gorilla glue or Liquid Nails were other options that came up on research.

Once they were installed and the glue dry, I took some sandpaper to the front edges of the ports to make a very slight radius and smooth out the 'seam' and plywood. Less rough edges theoretically = less turbulence = cleaner sound (especially @ louder volumes)... in theory! ; )

If I had a bit more patience, I might properly have set up a router and radiused the front edges of the ports as well, but close was good enough ; ) They ended up with about a 1/8" radius on the front edge, effectively taking about 1/16" off the total length of each, as far as tuned length goes. A Sharpee pen served as my 'touch up paint'.

If you're considering swapping out the woofer (or already have), these flared ports, installed as is ,with a bit of insulation in the box, should be a really lovely tuning for an Eminence Deltalite II S2512. I modeled it in a few programs as I've ordered one but don't have it on hand yet.

If anyone is interested, this is what figures I came up with from the modelling with the S2512:
67.74hz lowest poss F3 (-3db point of the frequency response): box tuned @ 57.60hz with S2012 - adds 2.1db boost @ 110hz
*sealed - 76.63hz F3
*stock porting gives 4db boost @ 110hz and f3 of 71.64hz

I didn't ask for the T/S parameters from Eminence for the stock woofer as I was only really interested in possible clean volume gain, not modelling its low end response. So sorry, don't have those numbers.

Also, as far as the question of 'Can it get louder, cleaner with a different woofer?' goes...
I ran a simple controlled test with pink and white noise through the amp with the stock Eminence Fender Special Order speaker (which has 93db efficiency, according to Eminence) and an Eminence Beta 12LTA I have on hand (it doesn't fit the holes properly, so i couldn't properly install it without drilling holes, which I didn't want to do) that has a stated 97.7db efficiency. I figured I'd measure about a 5db increase in volume with test tones, but it was actually more. I did the test 2x with the same results each time. The db meter was placed 1 foot away from the woofer, so this wasn't the traditional 1 watt @ 1 meter test, but a real world type test with pink noise and then white noise and a lot more than 1 watt of power.

With pink noise with gain all the way down, all buttons 'off', and all other knobs at 12 o'clock including master volume, I measured 8db more on my db meter with the Emi 12LTA than stock woofer. With white noise, it was 11db more (probably because of the whiz cone on the 12LTA and additional HF reproduction from it). Those differences stayed the same with the white noise at two different volumes.

So, yes, a more efficient woofer will make it effectively louder. BUT be sure to check the measurement of the mounting holes before ordering a replacement. I believe the S2512 will fit without drilling, but haven't proved it yet - perhaps someone else can attest to whether it's a 'drop in' replacement or not. I'll know soon enough I guess.

Some pictures below.
Happy modding!

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[at77]

As a follow up. I swapped out the woofer for the Eminence S2512. It fits the holes, but with a bit of finesse necessary - the holes line up but not perfectly, so you have to just put each screw in a few turns before you tighten any of them down entirely.

The S2512 goes significantly louder, clean. It's also louder at equivalent volume settings. BUT it has a very different EQ shape. The stock one comparatively has much more low end and a bit more of a pronounced 2.5khz 'high' boost. The S2512 is more 'linear' response, but also seems to have slightly deeper extension, though that's hard to say because the 100hz boost of the stock speaker is so strong, compared to the S2512.

All said and done, if I didn't want the extra few db of clean gain, I'd leave the stock speaker because it sounds great (especially after the insulation, flared ports and bracing).

One point of caveat - the terminals on the S2512 are 5-way/banana plug style, not the push on crimp connector on the stock woofer. So, you'll likely end up having to cut the connectors off and stripping the wire to get a good connection. I opted to replace the speaker wire entirely with some Gotham Quaxial I had on hand, just to be geeky. But that's it's own post that I won't bother with.

Overall, this amp is fantastic - I've been loving it as a jazz and funk guitar amp, so clean and clear.
Though it's rated as only 100w, it's a very clean and true 100w. It seems quite a bit cleaner and louder than my old genz benz shuttle 600 head, from memory anyway, which theoretically had significantly higher wattage. So, as always, don't let the wattage rating mean too much to you.

 

[azfatboy]

Wow, great thread. As a fellow Rumble 100 owner, and consummate tinkerer, this definitely gave me the itchies to start playing around inside my Rumble. But to be honest, I have no idea what you guys are talking about with a "100Hz bloom" or peaks or valleys or any of that. I wish I did. I suppose that will come with more experience. And I think some of the simpler ideas (batting and bracing) might be simple enough (and cheap enough) that I could try them anyway. Maybe I will hear a difference?

Anyway, thanks for a wonderful and informing thread.

P.S. @AstroSonic , what enticement could I offer for you to run one of your expert analysis on my project with a Bassman 410H enclosure? I just wanna know if I am wasting my time/money or if it would be worth it.

 

[alaskaleftybass]

Hi all, this was a very informative thread for me. I really enjoyed the positive interaction and sharing between the posters.
I have a different project I'm considering but it involves a Fender Rumble 112 v3 cabinet.
I'm thinking of replacing the stock speakers with the following: 12" Eminence with a Kappalite. Horn with 3" Faital 8ohm midrange.
I'm hoping @Passinwind and @B String can drop by and give their pro opinions.

Thanks to everyone for the valuable contribution to the thread. I really enjoyed it. I might start my own thread on the Rumble 112 but I stopped here first to see if anyone has any thoughts on my upgrades.

 

[steve_rolfeca]

You need to get hold of one of the folks who has box design software, and ask them to run the numbers on a Kappalite in the 112 v3 cab.

They can tell you what would need to do in terms of adjusting the existing ports to suit the Kappalite, and whether it was a good match to that box in the first place.

The stuff you see on this thread, is all about making minor adjustments to improve the performance of the OEM speaker in the Fender combo enclosure.

You'll also need to get someone with design chops to suggest a proper crossover circuit. You can't just toss a capacitor in with the Faital and expect it to perform to its full potential with the Kappalite- some smoothing will have to be done in the crossover region.

Parts won't be expensive, but some experimentation will probably be needed in order to fine-tune for the best results.

 

[alaskaleftybass]

You need to get hold of one of the folks who has box design software, and ask them to run the numbers on a Kappalite in the 112 v3 cab.

They can tell you what would need to do in terms of adjusting the existing ports to suit the Kappalite, and whether it was a good match to that box in the first place.

The stuff you see on this thread, is all about making minor adjustments to improve the performance of the OEM speaker in the Fender combo enclosure.

You'll also need to get someone with design chops to suggest a proper crossover circuit. You can't just toss a capacitor in with the Faital and expect it to perform to its full potential with the Kappalite- some smoothing will have to be done in the crossover region.

Parts won't be expensive, but some experimentation will probably be needed in order to fine-tune for the best results.

Thanks, those are excellent sugestions. Will do!

 

[at77]

Thanks, those are excellent sugestions. Will do!

Also, there's several decent enclosure design/speaker modelling programs online now that are free.
Here's one page that has a few different ones:
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There are others as well, just search around. I check an intended design or tuning with a few different programs to see if the results are similar - often they vary, but within a decent margin anyway.

 

[at77]

ps good to take the woofer out, btw, and take inside measurements. In some cases there are partitions or braces that affect the interior volume of the cab (as in the rumble 100 v 3, for example). Also be sure to account for the space taken up by the woofer, especially in these smaller boxes. Eminence has that info on their spec sheets for every driver.

 

[at77]

pps also highly recommend flared ports and also using the largest diameter you can get away with - cleaner, clearer bottom end and overall. for a 12" speaker, a single 4" is minimum (rule of thumb is 1/3 the diameter of the driver). dual 3 is good, dual 4 is good, single 6 also good. But length of port changes with all this, so you have limited options given the box you're dealing with.
if you don't buy a flared port, you can make your own with a 1/4" or 1/2" router radius bit or just sand it down.
I think the rule of thumb is to also add the value of the radius to the port length on each side. eg if you need a 3" long port and radius 1/2 on both sides, make it a 4" port.

 

[steve_rolfeca]

Latest mod update:

I've been enjoying the Rumble a lot- it has a warm, vintage vibe that makes a nice contrast to my hi-fi "big rig".

Still, it lacks some zing on top, and even judicious EQ can't fill in all of the low end that's missing with the sealed cab.

This all came to a head when I recently tried to make the necessary EQ adjustments to suit a set of flat wound strings on my 5 string P-Bass. I tried uncorking first one, and then both ports. Sadly, the imbalance between the open E and B strings reminded me that this cab falls pretty firmly into the "four-string friendly" category.

A quick check revealed that the Rumble head isn't the issue- both the extreme lows and highs are pleasing when I plug my IEM's into the headphone jack.

I suppose I could turn this into a big project, swapping out the driver and re-porting the cab. Instead, I think I'll leave the low end alone, and just try adding a tweeter.

In really bad, boomy rooms, the lack of sub-bass frequencies is actually helpful. And I have other, more suitable cabs when I really need to hit the brown note...

 

[steve_rolfeca]

Late update:

TB'er Jamie_Funk gave me a used Celestion Neo bass driver (BN12 300s) to play with. They are stupid expensive, and the tuning is odd (no low end, very flat through the mids with no midrange peak, and a typical guitar speaker rolloff in the treble).

Still, it handles 300 watts, weighs next to nothing, and free is my favourite price. Obviously, I had nothing to lose by testing it out.

At first, I was a bit disconcerted. On the plus side, it boosted the upper mids and treble without sounding harsh. It's also noticeably louder than the Eminence at the same volume setting.

But the big minus was a dramatic loss in the low end.

Interestingly, it started to sound better and better, the more I turned up the bass control. I'm now running it with one port open, and the bass control dimed.

The big boost on the low end doesn't muddy up the low mids. Overall, the amp now sounds full, punchy and perfectly balanced with the rest of the tone controls at noon. The B string on my Dingwall now sounds nearly as good as it does through my G-K/AudioKinesis rig at low volume. My NSD electric upright also sounds much more natural.

This mod has really renewed my enjoyment of this little combo. It's finally really B-string and Upright friendly, and weighs in at 22lb including mods. How crazy is that?

The only downside, is that the EQ compensation combines with the porting to make it go into cone rattle on a low B or C when I max out the volume.

Still, at this point it's much louder than a cheap $300 combo has any right to be. Given that I still have my lightweight Rig of Doom for larger venues, getting a good low B is more important to me than losing a couple of dB of maximum output.

I call this a big win...

 

[shfpdx]

I know I am late to this party, but this thread is flat phenomenal...I purchased a Rumble 500 with matching cab based on all the features (weight, power, 10s etc). And I really want to like it but like others the boom/mud was annoying when used in a big room or if not lifted off the ground (note: this device helped alot and fits a rumble 500). I play in a Tower of Power/Earth Wind & Fire band and need to cut through the mix. The volume and push was great, but muddiness was annoying and no growl. I followed this post and will be making these very modifications before I make a journey back into Ampeg or GK world. Thank you steve_rolfeca and fellow posters. You are the real deal.

 

[steve_rolfeca]

I know I am late to this party, but this thread is flat phenomenal...I purchased a Rumble 500 with matching cab based on all the features (weight, power, 10s etc). And I really want to like it but like others the boom/mud was annoying when used in a big room or if not lifted off the ground (note: this device helped alot and fits a rumble 500). I play in a Tower of Power/Earth Wind & Fire band and need to cut through the mix. The volume and push was great, but muddiness was annoying and no growl. I followed this post and will be making these very modifications before I make a journey back into Ampeg or GK world. Thank you steve_rolfeca and fellow posters. You are the real deal.

Glad to hear that you found some useful information!

BTW, if anyone would like to try the Celestion in their 100, private message me.

I've been getting back into 4-string territory lately, with a couple of different ABG's. They both sound much better with a full-range/flat response rig than a conventional, coloured bass amp.

So I put the stock driver back in the Fender, and traded it towards a nice little battery-capable powered speaker.

The Celestion is now surplus to requirements. I can leave it on the shelf until the right project comes along, but it makes more sense for someone else to be enjoying it. These things are quite expensive new, but I'd be willing to move it on at a friendly price.

 

[CallMeAl]

@steve_rolfeca ,
Thanks for an awesome thread and all these ideas!

I’ve been using a Rumble 100 faithfully as my gig amp for over 2 years. I’ve encountered the boom, and read about speaker mods, lining the cab and plugging the ports- but felt skeptical enough that I never tried any. I’ve had great results with setting the bass to 9:00 and using a tilt back wedge.

I found your thread today, and was inspired to try plugging the ports. I just used cloth towel as it is easy and reversible. I recorded some samples of both and thought while there was a difference, the results were not that dramatic. Maybe because this was at home, not in gig conditions? I tried to crank it, but my apartment has its limits!

On the fence about whether or not to pursue any further experimenting. I have been pretty pleased with how I’ve been running my Rumble lately. Either way, thanks again for the hard work, write ups, and all the food for thought!

 

[steve_rolfeca]

@steve_rolfeca ,
Thanks for an awesome thread and all these ideas!

I’ve been using a Rumble 100 faithfully as my gig amp for over 2 years. I’ve encountered the boom, and read about speaker mods, lining the cab and plugging the ports- but felt skeptical enough that I never tried any. I’ve had great results with setting the bass to 9:00 and using a tilt back wedge.

I found your thread today, and was inspired to try plugging the ports. I just used cloth towel as it is easy and reversible. I recorded some samples of both and thought while there was a difference, the results were not that dramatic. Maybe because this was at home, not in gig conditions? I tried to crank it, but my apartment has its limits!

On the fence about whether or not to pursue any further experimenting. I have been pretty pleased with how I’ve been running my Rumble lately. Either way, thanks again for the hard work, write ups, and all the food for thought!

Port adjustments were the least important things I did on my Rumble journey, and mostly only effective for my 5-string basses.

Bracing and lining were the most important, and let me run the bass up around noon for a tighter and more pleasing low end.

 

[shfpdx]

Thanks to Steve and everyone for the Rumble Mod Thread. As a followup, I lined and reinforced both my Rumble 500 combo and extension cab. The results tightened up the sound and removed most of the boom. Just for experimentation purposes, I temporarily hooked up both cab connections to a raw studio monitor amplifier (125 watts) and a bass preamp to see what the cabs did with a different source...and the results were dramatic...completely different tone...the Fender signature sound was replaced by the temp sources tone and eq. The boxiness was gone (due in part, I am sure, to the Rumble mods). The classic Fender sound from the amp is designed to be just that..rumble. I was trying make this amp sound like a GK...and I got close with the mods, but I ended up trading out/cash the stack for a GK 700rbii and a 2x12 Neo (I play in a EWF-TOP-Chicago band and the GK cuts through better, to me), but I would jump right back into the Rumble series if I moved to a 3-5 piece kicking rock outfit. If you have a Rumble, definitely take the time to mod the cab per this thread. It works. Thanks again to all. Great thread.

 

[JRA]

steve_rolfeca : nice work! great too, for all of the followups.

 

[Balog]

Late update:

TB'er Jamie_Funk gave me a used Celestion Neo bass driver (BN12 300s) to play with. They are stupid expensive, and the tuning is odd (no low end, very flat through the mids with no midrange peak, and a typical guitar speaker rolloff in the treble).

Still, it handles 300 watts, weighs next to nothing, and free is my favourite price. Obviously, I had nothing to lose by testing it out.

At first, I was a bit disconcerted. On the plus side, it boosted the upper mids and treble without sounding harsh. It's also noticeably louder than the Eminence at the same volume setting.

But the big minus was a dramatic loss in the low end.

Interestingly, it started to sound better and better, the more I turned up the bass control. I'm now running it with one port open, and the bass control dimed.

The big boost on the low end doesn't muddy up the low mids. Overall, the amp now sounds full, punchy and perfectly balanced with the rest of the tone controls at noon. The B string on my Dingwall now sounds nearly as good as it does through my G-K/AudioKinesis rig at low volume. My NSD electric upright also sounds much more natural.

This mod has really renewed my enjoyment of this little combo. It's finally really B-string and Upright friendly, and weighs in at 22lb including mods. How crazy is that?

The only downside, is that the EQ compensation combines with the porting to make it go into cone rattle on a low B or C when I max out the volume.

Still, at this point it's much louder than a cheap $300 combo has any right to be. Given that I still have my lightweight Rig of Doom for larger venues, getting a good low B is more important to me than losing a couple of dB of maximum output.

I call this a big win...

Did you have to modify the mounting holes for the Celestion? My stock speaker is damaged and looking at the different possible replacements. Thanks!

 

[Hankenstein]

Unless someone comes up with a schematic, and I can find an easy way to add a pre/post switch for the XLR out, my Rumble mods are finished.

Got a kickstand from Leland at Speaker Hardware, and now I have a tiltback!

View attachment 465897
View attachment 465896

Interestingly, it makes quite a difference to the low end.

I was surprised, because my ported AudioKinesis 112 cab sounds virtually identical whether it's flat on the floor, tilted back a few degrees, or raised a foot and a half. Just a slight improvement in the treble when it's tilted back and I'm standing nearly on top of it.

In contrast, I have to bring the bass and low mids back up to noon to bring back the low end that's lost when I tilt the Rumble, and the mids and highs open up quite a bit as well.

Won't know until I gig it, but I suspect that this will be useful in The Room From Hell on Sunday night. Will give a gig report ASAP.

I went to Speaker Hardware but could not find this part. Got a link?

 

[steve_rolfeca]

Once more into the breach!

I lost my main gig during COVID. I'm still playing once a week, but my away dates and other pickup work pretty much dried up.

I've been leaving my G-K/AudioKinesis rig in one place, just showing up with my bass of the day, This has helped my chronic back trouble, and it's nice to always run through the mini-Rig Of Doom.

However, I just landed a great position playing for a kid's gospel choir, and there's a lot of cartage involved- there are multiple rehearsal locations, and their calendar is filling up with dates all over the city.

PA situations vary widely by venue, so I'm carrying lots of gear just in case. Lugging all this stuff around is playing hell with my back, so I've decided to re-think the gear situation.

This gig calls for a darker, more Fender-like tone than I normally use. My micro-rigs (Bose, Headrush) don't cut it volume-wise, and if possible, I'd like to go back to a one-trip carry. Given that I can get away with the MB200 (volume between 9 and 10 o'clock most of the time) into my 4-ohm 1x12, I'm pretty confident that another Rumble 100 will do the trick.

A used Rumble arrives on Friday. I've still got some leftover dowel in the garage, Wal-Mart is just around the corner, and thanks to the other contributors on this thread, I think I'm going to pick up some flared ports as well...