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Fender Rumble Club

#7,461
My Rumble 500 combo just continues to surprise me !
Had a gig yesterday afternoon at a local bar,backing mainly vocal and guitar students tutored by my fellow band mates at a family concert.
The venue is indoors,dark, like a long concrete bunker, and is just darn loud !
Played many gigs there over 20 years and would always use the biggest rig I had at the time because you just had to.

I boldly took the Rumble !
Even with up to 4 guitars blazing away in some songs , being crammed into the back corner and having to stand beside my Rumble , which was perched on a chair , I was still happy with my stage sound.

Better still a 14/15 year old lad with the skills of "Flea" playing a Fender Jazz (as I do) took the stage and he was an awesome player.
This gave me a chance to listen to FOH, and was really happy with what I heard.
I thought my DI and SVT sim sounded fantastic and was quick to point this fact out to my mate mixing on the desk...
He then showed me, with a grin i might add, the Bass channel was muted and it was only the Rumble combo cranking on stage we could hear !!!! I still cant believe it !!!!

just had to share :)
 
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#7,462
While waiting for my replacement Rumble 100 to be delivered, I've been roughing it with my old Ampeg BA-108, which sounds good, but is absurdly heavy. Well, last night it suddenly died on me, leaving me suddenly ampless. It's just a blown fuse, I think (though why it suddenly blew is anybody's guess), but I soon discovered that this specific type of fuse is hard to come by in my neck of the woods. That gave me just the excuse I needed - I ran straight out and got myself a brand new Rumble 40. Woot! I now have a very capable and light backup amp that sounds great (and WORKS), and as soon as I can get the fuse replaced in my Ampeg, it's going in the classifieds.

Rumble40.JPG
 
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#7,463
Here's something interesting to add to our knowledge base.
billfitzmaurice said:
It's called Boundary Reinforcement, which boosts bass sensitivity by 6dB in the low end when you have the cab close enough to one wall, and by 12dB in a corner. The distance required to get these free dBs is approximately 2.8 feet or less from the front of the cab to the boundary/boundaries. With placement further away you get room cancellation modes that actually suck out the bass. Boundary reinforcement and cancellation modes affect every type of speaker equally, be it sealed or ported or horn, and in the case of ported front or rear makes no difference.
Click to expand...
and this from Alex Claber designer and maker of Barefaced speaker cabinets
"

Thanks to Bill Fitzmaurice (horn speaker guru) for mentioning this and getting me googling...

The Allison Effect was named after Roy Allison who realised that room boundaries seriously affect bass reproduction, not only in terms of boundary reinforcement (generally good for us) but also boundary cancellation.

"The best bass response is achieved by having the bass source either very close to or very far away from reflective surfaces. This generally means close to the rear and side walls and floor and far from the far wall and ceiling."

Why is this?

If you place your speaker 1/2 a wavelength away from a boundary then, at the frequency that corresponds to that wavelength, the sound will be reinforced significantly. We're talking the kind of boost you get from cranking a parametric EQ with Q narrow. If this particular frequency is a boomy/muddy one, it will not be fun. And if you're playing an acoustic instrument, feedback city...

The flipside: If you place your speaker 1/4 wavelength away from a boundary, then at the frequency that corresponds to that wavelength (twice the previous frequency if the speaker hasn't moved) the sound will be cancelled significantly. A typical amount would be -15dB at the null frequency. Nasty. Truly tone sucking.

The solution? Place your cab so it's less than 1/4 wavelength (of the upper bass range i.e. 100Hz) away from any boundaries OR more than 1/2 wavelength (of your lowest frequency) from any boundary.

How does this relate to the real bass playing world? A 41Hz (low E) sound has a wavelength of 27.5 feet (I'm sorry, I'm still hanging onto the Imperial system). A 31Hz (low B) sound has a wavelength of 36.5 feet. So, fellow four stringers, you need to place your cab at least 13'9" away from any walls (fivers, 18'3"). So that's how to avoid peaky boundary reinforcement.

To avoid notching boundary cancellation you need to be within 1/4 wavelength of a boundary in the range of 31 to 100 Hz. So really you need to get your cab within 2'10" of a boundary. Which part of the cab, you may ask? The bit that's making the sound, i.e. the bass speakers themselves and the ports. So given that most bass cabs are 14"-20" deep, you need to get the cab really close to the back wall, but not so close that the ports' operation (if rear-ported) is affected. Think 6"-12" away.

So what's the best solution on the gig? Place your cab on the floor or on a short stand. Place it close to the rear wall. Place it close to one side wall. The far wall and the other side wall should be far enough away unless you're playing a boxroom. The ceiling will often be a pain, but one boundary causing nulls and peaks is a lot worse than all six getting in on the action.

Alex"
 
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#7,464
Linnin said:
Here's something interesting to add to our knowledge base.

[Allison Effect]
Click to expand...

This is very useful information!

I was aware that reflective surfaces affected bass audio propagation, but never saw hard numbers attached to it. It looks like you could fine-tune your sound by moving the speakers just a few inches at a time until you zero in on that sweet spot.
 
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#7,465
Scott Truesdell said:
This is very useful information!

I was aware that reflective surfaces affected bass audio propagation, but never saw hard numbers attached to it. It looks like you could fine-tune your sound by moving the speakers just a few inches at a time until you zero in on that sweet spot.
Click to expand...
I knew a little about it, but not enough. Does anybody really think about moving their combo or speaker cabinets around when EQing their rig to the room and mix? I like to stay about a foot away from any wall because it sounds better. Now I know why.
 
#7,466
Kinda reminds me of when I was big into home theaters.
They say the best way to find where to put your subwoofer was to put it in your prime seating location, then crawl around the outside of the room on your hands and knees to find where it sounded best. That is where to put the subwoofer.

Kinda sorta same idea, putting the speaker where it sounds best as opposed to where you "want" it to go.

Ultimately, the best and final position was wherever the wife told me to put it that didn't "look stupid" in the room, lol.
 
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#7,467
My take-away from that Allison Effect post is if you are getting a notch or boom out of your rig at any given venue, try moving the speakers a couple of inches and see if it improves. Just like radio antennas, that is 100% free power. Compensate with EQ as a last resort.

If you have a audio spectrum analyzer (you only need a cheap one; we're looking at relative values here, not absolute values. I've seen components for <$25) you could stick it near where you'd have a FOH console and have someone signal you when the graph goes flat as you jostle your rig around on stage. Hand signals: thumb down = notch -- move closer to wall; thumb up = spike -- move away from wall; hand flat = signal flat.

It would take like 12 seconds. Job done!
 
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#7,469
Linnin said:
Here's something interesting to add to our knowledge base.

and this from Alex Claber designer and maker of Barefaced speaker cabinets
"

Thanks to Bill Fitzmaurice (horn speaker guru) for mentioning this and getting me googling...

The Allison Effect was named after Roy Allison who realised that room boundaries seriously affect bass reproduction, not only in terms of boundary reinforcement (generally good for us) but also boundary cancellation.

"The best bass response is achieved by having the bass source either very close to or very far away from reflective surfaces. This generally means close to the rear and side walls and floor and far from the far wall and ceiling."

Why is this?

If you place your speaker 1/2 a wavelength away from a boundary then, at the frequency that corresponds to that wavelength, the sound will be reinforced significantly. We're talking the kind of boost you get from cranking a parametric EQ with Q narrow. If this particular frequency is a boomy/muddy one, it will not be fun. And if you're playing an acoustic instrument, feedback city...

The flipside: If you place your speaker 1/4 wavelength away from a boundary, then at the frequency that corresponds to that wavelength (twice the previous frequency if the speaker hasn't moved) the sound will be cancelled significantly. A typical amount would be -15dB at the null frequency. Nasty. Truly tone sucking.

The solution? Place your cab so it's less than 1/4 wavelength (of the upper bass range i.e. 100Hz) away from any boundaries OR more than 1/2 wavelength (of your lowest frequency) from any boundary.

How does this relate to the real bass playing world? A 41Hz (low E) sound has a wavelength of 27.5 feet (I'm sorry, I'm still hanging onto the Imperial system). A 31Hz (low B) sound has a wavelength of 36.5 feet. So, fellow four stringers, you need to place your cab at least 13'9" away from any walls (fivers, 18'3"). So that's how to avoid peaky boundary reinforcement.

To avoid notching boundary cancellation you need to be within 1/4 wavelength of a boundary in the range of 31 to 100 Hz. So really you need to get your cab within 2'10" of a boundary. Which part of the cab, you may ask? The bit that's making the sound, i.e. the bass speakers themselves and the ports. So given that most bass cabs are 14"-20" deep, you need to get the cab really close to the back wall, but not so close that the ports' operation (if rear-ported) is affected. Think 6"-12" away.

So what's the best solution on the gig? Place your cab on the floor or on a short stand. Place it close to the rear wall. Place it close to one side wall. The far wall and the other side wall should be far enough away unless you're playing a boxroom. The ceiling will often be a pain, but one boundary causing nulls and peaks is a lot worse than all six getting in on the action.

Alex"
Click to expand...

I've read about (and experienced) this quite a while ago.
What kept me wondering was this: (good) manufacturers take lots of efforts creating amps/combos/speakers which will reproduce the original source sound as natural as possible, doing research on frequency ranges, checking peaks, lows, etc. Or maybe they aim for another target and mold the sound to get a specific type of sound.

So how does this translate when you push a speaker against a wall or in a corner to gain extra low?
Does it destroy the intended sound just for the sake of some extra low freq DBs?
Do you get equally low response on a certain frequency band? Or just some high peaks for certain frequencies?
Or don't you care, as long as you get more low, it's OK?
Just wondering...
 
#7,470
eric_B said:
So how does this translate when you push a speaker against a wall or in a corner to gain extra low?
Click to expand...
See, that's exactly what you don't want to do, Eric. You want to stay at least a foot away from any wall, and not shoved in a corner. So you would be at least at foot away from the back and side wall that forms the corner. If you get too much boost, you're just going to have to cut the bottom end.
 
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#7,471
Linnin said:
See, that's exactly what you don't want to do, Eric. You want to stay at least a foot away from any wall, and not shoved in a corner. So you would be at least at foot away from the back and side wall that forms the corner. If you get too much boost, you're just going to have to cut the bottom end.
Click to expand...

I completely disagree with this. I would always start with your bass rig hard into a corner wherever possible. If it's too boomy then move it but as soon as you pull the rig away from the wall you start causing uneven response from boundary reflections causing sharp notches in output.
 
#7,472
alexclaber said:
I completely disagree with this. I would always start with your bass rig hard into a corner wherever possible. If it's too boomy then move it but as soon as you pull the rig away from the wall you start causing uneven response from boundary reflections causing sharp notches in output.
Click to expand...
Alex this seems totally contradictory to your statement, or am I simply misreading and therefore misunderstanding.
Linnin said:
"To avoid notching boundary cancellation you need to be within 1/4 wavelength of a boundary in the range of 31 to 100 Hz. So really you need to get your cab within 2'10" of a boundary. Which part of the cab, you may ask? The bit that's making the sound, i.e. the bass speakers themselves and the ports. So given that most bass cabs are 14"-20" deep, you need to get the cab really close to the back wall, but not so close that the ports' operation (if rear-ported) is affected. Think 6"-12" away."
Click to expand...
Perhaps you would be kind enough to clarify.
 
#7,476
Linnin said:
Alex this seems totally contradictory to your statement, or am I simply misreading and therefore misunderstanding.
Click to expand...
I don't think it is...

Having spent a few years mucking around with radio (ham and marine) I have a small but practical pool of experience with nulls, notches and gain. Waves is waves. What works with RF also works with audio waves, seismic waves (earthquakes), ocean waves, and even traffic on freeways and economic trends.

This is also why moving mics just a few inches can sometimes solve a pesky feedback problem.

Think 6"-12" away."
Click to expand...

Perhaps you would be kind enough to clarify.
Click to expand...

Looks like 6 to 12 inches away is a good starting point.

If we could see audio waves in the air, direct and reflected, and how they interact with each other, that would be awesome!
 
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