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Fender Rumble 350 to Two 410's?

#21
Please, please bury this under powering myth 6 feet deep.

This myth has a root of truth when used in a full range system (with tweeter) driven well into clipping, but this has no effect on the LF drivers voice coil other than pure thermal energy (power integrated over time) which in a square wave is 2x the power of an unclipped sine wave of equal peak amplitude. In practice, due to power supply sag, it's usually more like 1.5x.

Friction of the voice coil? There is no friction as its suspended in a zero contact operating environment.

Virtually every speaker jack pair on speaker cabinets sold in the last 4 decades is wired in parallel. Series wiring of stage monitors is not at all common and in fact is only done when trying to drive a square peg into a round hole.

Theoretical physics always needs an "engineering adjustment" to agree with the real world.
 
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#22
And yet another example...........

rydin4lifebass said:
So, when you say "daisy chain" the cabs, you mean that one of the inputs on the cab is really an "input" and the other is an "output" to another cab.
Click to expand...

TheEnthBass said:
yes, that would connect them in series making two 4ohm cabs into an 8ohm load ......
Click to expand...

Sorry..........but again, no mention of making special cables or connection boxes.
 
#23
when I said most cabs aren't set up for that... might have said it in a second post but the message was that it can be run in series and that often monitors are set up for that. even stated his cab was not given that it stated the jacks were parallel. most are that is true, but they can be wired that way if desired. most applications one wouldn't but for special cases where there is plenty of power it can be done to match loads. there are lots of instances where that would be a good idea. pa systems often do this, monitor set ups often do this. this isn't one of the situations, I said that too. I was just trying to let him know the difference between parallel jacks and the resulting load vs. running them in series and the resulting load and how that related to the resulting power seen by each set up. wasn't saying it was a good idea. I think that was fairly clear but maybe I should have been more specific.
 
#24
I've used monitors and Mains in series a number of times. It isn't ideal but definitely not rare. interesting statements about under powered. never heard it that way. I was always told repeated clipping and the introduction of a, square wave created an issue in the voice coil over time that could result in fusing the coil. maybe i'm wrong with that. so you are say that clipping is fine essentially or i'm missing some nuance there. otherwise you just have a lack of power from under powering which certainly results in a difference of tone. math-physics-engineering-real life- that is true.
 
#25
if not then why not wire the cabs for series and run the two four tens. I imagine you have less power to each cab but more surface area right? Is there an advantage/disadvantage scenario with that or is there some other reason since your saying it can't damage the loads that its just a bad idea.
 
#26
TheEnthBass said:
if not then why not wire the cabs for series and run the two four tens. I imagine you have less power to each cab but more surface area right? Is there an advantage/disadvantage scenario with that or is there some other reason since your saying it can't damage the loads that its just a bad idea.
Click to expand...

It works out to be a wash..............

Lower wattage output takes away the gain from increased speaker area.

Basically, you end up carrying another speaker cab to be as loud as you were before.
 
#27
that figures. more surface area can mean more low end but without the power to support that I would assume you certainly wouldn't be as responsive. I wonder if it just gets muddier. given that when I run monitors like this, or tops on a small PA, its just because I need to place the source in various locations and am limited by number of power amps and channels. usually they are just carrying vocals and guitar to the singers and tone is less of a worry, I just need to get something there. I also have more power than I need to power the chain in series working with small wedges and tops for little halls so I haven't heard an issue.
 
#28
This is the under powered argument I've always been referred to. from a car audio site but certainly makes a lot if sense. Is the consensus here that this is not true? I've experienced something similar before trying to push an old Peavey rig too hard into a 2x15 cab and burnt coils repaetedly even though the speakers were rated far higher, more than double the head. It was one of my first rigs as a kid paying punk and metal. I swapped speakers in that two times before a friend who runs several large venue systems told me essentially this below.

Many people drive their amplifiers into what could be called a square wave When an amplifier is pushed that hard, it is actually possible to drive the speaker with twice as much power as the amplifier can cleanly produce into the speaker. As you can see below, the yellow sine wave is the maximum 'clean' output that the amp can produce. When an amplifier is pushed way too hard, the signal will eventually look like the white line. The effective voltage of the white line is ~1.414 x the yellow line. This means the the total power driven into the speaker by the clipped (square wave) signal is double the power delivered by the 'clean' signal (yellow line). This means that the power is double but the cooling of the voice coil will not increase in proportion with the power increase (since the voice coil isn't moving as much as it needs to be for the given power dissipation). This will lead to the voice coil overheating. If we compared the output of a 100 watt amp (the one that's clipping) to a 200 watt amp, the 200 watt amplifier would be able to push the speaker as much as 40% farther than the 100 watt amp (depending on the frequency of the signal). This extra travel (in each direction from its point of rest) would result in added airflow around the voice coil.
 
#29
I would definitely like to understand if this is wrong. essentially it would mean there is no inherent danger to running an under powered cab unless the head is being driven very hard trying to maximize the volume one wanted from their under powered cab. I bet that happens often enough if someone runs a small head and has a guitar player or drummer that keeps getting louder... But if you were aware of this and didn't push too hard there would be no worry about under powering except that you usually end up lacking tonally in my experience and sounding a bit muffled. any one want to refute this? from my experience it seems to be true but i'm certainly open to learning more if i'm mistaken.
 
#31
Ya, a 300w amp can have up to twice the wattage available for peaks. So if you have a cab rated for 500w and you get a peak that's 600w, you will blow the cab. But if your peak is below the 500w threshold, you can do it all day long and it won't blow the cab. So it's really OVERpowering that blows speakers, not UNDERpowering.
 
#32
well in an instance "underpowering" by applying a 300 watt head to two 300 watt cabs in series then peaking delivers 300 at peak to each. right on the line, wouldn't trust that knowing how manufactures are not totally responsible in labeling rms and peak accurately, but maybe not an issue. def ok if wise enough not to drive the amp to peak. could do the math in other situations and see a risk. though technically at that point you are over powering the numbers on the rig imply something under powered.
 
#33
Peak power is exactly double the power based on RMS voltage ("RMS" power). There is no difference other tnan a units conversion. Take RMS voltage of a sine wave, convert to peak voltage by multiplying by 1.414, then square the result to get power and 1.414 squared is 2 which is where the factor of 2 comes from.

JBL had a speaker component whitepaper regarding derating for clipped signal that was intended for OEM manufacturers who used their components in finished products. I haven't seen it in a while, but it goes into what I have discussed previously.
 
#34
TheEnthBass said:
I would definitely like to understand if this is wrong.
Click to expand...

Really?
Several people have tried to explain it to you yet you continue to argue.
That is not how one "understands" something.
Your basic beliefs and understanding of this topic are incorrect.
Stop arguing with people that do understand and start learning.
Why ask questions and then disregard the answers?

Do some google searching on the topic and then start reading and learning.

I won't bother repeating what others have already stated on this topic.
It's appears to be falling on deaf ears.
 
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#35
Hey TheEnthBass... I second fkh006's suggestion that you learn more before preaching your ideas as gospel to others. Your "arguments" in your powered speaker thread go a long way to reinforce this opinion. 0 out of 2 is not a good track record.
 
#36
so for the record, a "underpowered" speaker rated at 300 watts that is powered by an amp that offers 200 Watts gets how much power when pushed to clip. 400 right, enough where under powering surpasses the recommended power and could cause damage. if that is not true, you folks said it is. so again I don't see where i'm wrong.
 
#37
this has really become a bad joke at this point with a bunch of quasi knowledgeable folks arguing that under powered speakers are a good idea and that you cant arrange loads in series. more interested in arguing symantics than reality. I thought physicists were out of touch. what a crock
 
#38
TheEnthBass said:
so for the record, a "underpowered" speaker rated at 300 watts that is powered by an amp that offers 200 Watts gets how much power when pushed to clip. 400 right, enough where under powering surpasses the recommended power and could cause damage. if that is not true, you folks said it is. so again I don't see where i'm wrong.
Click to expand...
Dangnab it, that is NOT underpowering. That is OVERPOWERING! Seriously, dude...quit trying to be right when you're clearly wrong, and actually try to learn something by people who know way more about it than you do.
 
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#39
I think you misunderstand why your comments have been challenged.

1. A 200 watt rated amp can deliver as much (in theory) as 400 watts under the hardest clip conditions, but because of power supply inefficiencies won't ever deliver the theoretical maximum and will probably settle at around 300 watts (per my 1.5x RMS rating example). This will vary based on the stiffness of the power supply and power source. It should also be noted that the bass won't sound very good, even to those fans of overdrive so it's about the most extreme example possible. Now this condition won't be very friendly to tweeters because of the harmonic series generated by the clipped signal, and the corssover components might not be all that happy about this signal either.

2. As far as series connections, nobody said that you CAN'T wire your speakers to be connected in series, but that the industry as a whole does NOT do this and has not offered this option for (as I said) 4 decades at least. It is not common, and in fact is very rare to connect speaker cabinets of any kind in series. This includes stage monitors, in the 35 years of my involvement in the pro audio world (at the rouring level) I have never seen a system wired for series connections ever. That's thousands and thousands of shows, many different systems.

Many folks here come to learn, expand their understanding of the gear, how it works and WHY it's done the way it's done. I whole-heartedly support anybody who wants to expand their knowledge and learn more about anything related to music. Confusing folks with comments that are not based on reality and the real world is not very helpful to these discussions. IMO, anyway.
 
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