• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join free Log in
    Want zero display ads or expanded classifieds tools? Compare plans.

Interesting conversation about speakers and ohms

#42
JimmyM said:
If that were true, then you couldn't amplify guitars and basses with fuzz pedals or synthesizers.
Click to expand...
Jimmy. That is a square wave input I'm talking about the output signal, This is just what I have learned so I was always careful not to drive a small amp,"fet" too hard. I am not trying to say they will fail I am saying they could. I guess everyone on here knows better than me though, by the comments I see lol
upload_2015-6-23_18-36-31.jpeg
Look at the duration at peek power of the square wave it is much longer than a sine wave so the speaker is at high voltage longer and the voice coil can overheat.
 
Last edited:
#45
Arthur SX said:
Jimmy. That is a square wave input I'm talking about the output signal, This is just what I have learned so I was always careful not to drive a small amp,"fet" too hard. I am not trying to say they will fail I am saying they could. I guess everyone on here knows better than me though, by the comments I see lol
Click to expand...
If they fail, it will be because the speaker was OVERPOWERED, not underpowered. Beyond an amp's RMS wattage, it can put out up to twice as much on peaks when you start overdriving it. Some people don't know that there's all this extra power, and they mistakenly believe that the cab blew due to being underpowered. Take that same square wave that you're talking about and input it to your cab at a reasonable level and you can play it all day long and never blow the cab.
 
  • Like
Reactions: mbelue, moody and Bob Lee (QSC)
#48
JimmyM said:
If they fail, it will be because the speaker was OVERPOWERED, not underpowered. Beyond an amp's RMS wattage, it can put out up to twice as much on peaks when you start overdriving it. Some people don't know that there's all this extra power, and they mistakenly believe that the cab blew due to being underpowered. Take that same square wave that you're talking about and input it to your cab at a reasonable level and you can play it all day long and never blow the cab.
Click to expand...
Ok I guess you can put it that way but you already knew this and I was trying to help someone who was not so sure on wattage vs impedance ect. I like you jimmy and I read your posts all the time.
 
  • Like
Reactions: JimmyM
#50
Bass_Pounder said:
Wrong.............

Keep reading, then go read the FAQ's.

You CANNOT damage a speaker by feeding it too little power.
Click to expand...

Correct.
If anyone wants to take a small portion away from that white paper this would be it:

C. For musical instrument application, where
distorted (overdriven) output may be a musical
requirement, the system should be powered with an
amplifier capable of delivering only one-half of the IEC
rating for the system.
Discussion: Much rock music is produced at full
output with the amplifier well into clipping, and this is a
matter of musical choice. When an amplifier capable of,
say, 300 watts of undistorted sinewave output is driven
well into clipping, its output power can approach 600
watts! So, Berating the system to one-half its IEC power
will result in safe operation of the loudspeaker.
 
  • Like
Reactions: Bass_Pounder
#51
Arthur SX said:
Ok I guess you can put it that way but you already knew this and I was trying to help someone who was not so sure on wattage vs impedance ect. I like you jimmy and I read your posts all the time.
Click to expand...
Thanks man! I just try to help. There's a lot of BS floating out there about how sound works, and I used to fall for it, too. But in my defense, back in those days, we didn't have any internet to get so much great personalized advice from some of the top names in the industry so we had to rely on guys who acted like they knew more than us but didn't know jack ;)
 
  • Like
Reactions: kcole4001 and Howlin' Hanson
#52
Arthur SX said:
Jimmy. That is a square wave input I'm talking about the output signal, This is just what I have learned so I was always careful not to drive a small amp,"fet" too hard. I am not trying to say they will fail I am saying they could. I guess everyone on here knows better than me though, by the comments I see lolView attachment 639859Look at the duration at peek power of the square wave it is much longer than a sine wave so the speaker is at high voltage longer and the voice coil can overheat.
Click to expand...
 
#53
I've seen speakers come apart because the cabinet was not properly tuned. The voice coil came right through the front. Guy had these home made bass bins back in the day. He didn't have a clue what he was doing. He loaded them with EVL's and powered them with a couple of Peavey CS800's. Blew the voice coils right through the front of the dust caps. The speakers hit their resonance frequency and just went nuts I guess.
 
Last edited:
#54
Arthur SX said:
Jimmy. That is a square wave input I'm talking about the output signal, This is just what I have learned so I was always careful not to drive a small amp,"fet" too hard. I am not trying to say they will fail I am saying they could. I guess everyone on here knows better than me though, by the comments I see lolView attachment 639859Look at the duration at peek power of the square wave it is much longer than a sine wave so the speaker is at high voltage longer and the voice coil can overheat.
Click to expand...
Allthough a very simplified example the power is doubled in this case. As long as speaker can handle the plus of power there is no concern nothing at all.
Keep in mind the example above meets sounds like done by Mr. Lemmy Kilmister.
In this case the power handling of the cabs should be twice as much as the signal "average" because there is no more crest (no more dynamics) that provides VC cooling based on "additional" movement of the speaker (which is normally based on dynamics AND crest).

A somewhat overloeaded sound is far away from those power considerations. I assume not more then 1/3 of amplifier rated power if distortion becomes very well audible. Furthermore a "dirty sound" solo does not overheat voice coils at once even on stage volumes.

The "simplified" example above is missing all of dynamics and decay, that's the main problem to state general thumb of rule with simplified "square" modellings.

Hope that helps.
 
Last edited:
#55
4 ohm SPEAKERS is way different than 4 ohm CABS. you can wire up 4 x 4 ohm speakers and make a 16 ohm cab. You can wire up 2 x 8 ohm speakers and make a 4 ohm cab.

The guy probably means 4 ohm CABS. they are most likely getting an amp's full wattage potential.
 
  • Like
Reactions: walterw
#58
GreyBeard said:
I've seen speakers come apart because the cabinet was not properly tuned. The voice coil came right through the front.
Click to expand...
which is the other actual way speakers fail, over-excursion. (like @BurningSkies said, my cabs are also sitting in my storage space getting underpowered as we speak :))
 

Latest posts

Top Bottom
Back