hearing distortion does not mean your amp is clipping! They look different on a scope. Some amps distort before going into clipping, some will go straight into clipping. Notch distortion is what tube amps are known for. Solid state output devices don't naturally notch distort, they tend to go straight into square wave or clipping. Clipping blows speakers! Distortion, not so much
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500 Watt Head & 800 Watt Cab?
- Thread starter john_martin_sai
- Start date
Sorry no, while the output of an amplifier is measured in volts. With no signal to amplify, the voltage from the most powerful amp is still zero volts. So no cigar tonight
oh, it was just an analogy.
although it can be the other way around in the OP's situation and it would still be safe.
i know... my svt 4 pro is driving a 250 watt hartke pro for 2 years now (i dont do crazy stage volumes though)
bongomania
Commercial User
Nope. First, "distortion" just means any change to the signal whatsoever. It includes clipping. So "all clipping is distortion, but not all distortion is clipping". Second, not all clipping is square waves. Thirdly, please do not go around spreading that tired old myth about clipping blowing speakers.
All of these technical arguments are beyond my scope of electronics knowledge,.....but.....
...with my new GK MBE 500w Head - GK MBE 800w 410 Cab......
I gather that if I am pushing it, even a little beyond it's normal capabilities, for more than 30 minutes.....
...I should turn off the tweeter (no adjusting it on this model),...while paying close attention to any indication of 'clipping' and 'overheating'.
I hope I at least have that right!
...with my new GK MBE 500w Head - GK MBE 800w 410 Cab......
I gather that if I am pushing it, even a little beyond it's normal capabilities, for more than 30 minutes.....
...I should turn off the tweeter (no adjusting it on this model),...while paying close attention to any indication of 'clipping' and 'overheating'.
I hope I at least have that right!
billfitzmaurice
Commercial User
- Sep 15, 2004
- 16,860
- 278
- 76
- Disclosures
- Owner, Bill Fitzmaurice Loudspeaker Design
Clipping and distortion are the same thing. Nothing in your post is accurate, and repeating this nonsense only leads to the sort of confusion that the OP refers to in his original question.
And OP, if misinformation is what you're looking for HarmonyCentral is the place to find it.
If you do so you may cook the LPad and/or crossover. Never turn it all the way down, perhaps the 1/4 level being as low as you want to go. Bottom line, if you run with a lot of distortion don't use a cab with a tweeter. Now stop kvetching about all this and go play your bass already.
Yes, you'll be fine. Key to remember, wattage ratings on cabs are thermal, so figure HALF of that as the mechanical limit, but don't worry about numbers, keep an ear on your speakers. If they start to strain or fart, lower the bass eq and/or volume- mids get you heard, low bass eats up your power. Otherwise, just play and don't worry.
....another 'statement' that seems to contradict most other opinions I've read here on TalkBass.
I guess this person assumes that the player with a lower rated amp will tend to 'push' it too hard.
I think it's time for all amp manufacturers to get together and put out a clear and definitive explanation of all the potential consequences of mismatched amps & cabs (that all can agree with).
Invalid Link Removed
"A: It’s better to have the amp be rated at a higher power than the speaker. Since you’ll be cognizant of this, you’ll be careful not to drive the amp too hot. Even if you go a little bit over what the speaker is rated for, it’s a linear curve, so the speaker will oftentimes survive just fine.
The problem is when the speaker is rated at a higher power than the amp, and you drive the amp so hard it clips. This creates a very sharp change in voltage which will blow out most speakers."
I guess this person assumes that the player with a lower rated amp will tend to 'push' it too hard.
I think it's time for all amp manufacturers to get together and put out a clear and definitive explanation of all the potential consequences of mismatched amps & cabs (that all can agree with).
Invalid Link Removed
"A: It’s better to have the amp be rated at a higher power than the speaker. Since you’ll be cognizant of this, you’ll be careful not to drive the amp too hot. Even if you go a little bit over what the speaker is rated for, it’s a linear curve, so the speaker will oftentimes survive just fine.
The problem is when the speaker is rated at a higher power than the amp, and you drive the amp so hard it clips. This creates a very sharp change in voltage which will blow out most speakers."
- Dec 28, 2010
- 357
- 3
- Disclosures
- Art of Noise Audio, fEARful builder
I'm really surprised you would say that, Bill. Wouldn't it be more accurate to say that clipping causes distortion. Certainly there are many types of distortion that have nothing to do with clipping.
I will agree that too little power never damages a speaker. However, an under powered amp driven to severe clipping can. This is because clipping can effectively double the power delivered to the speaker. If the driver doesn't have sufficient cooling to dissipate the heat caused by that extra power, then it can become damaged.
A fully clipped sine wave will become a square wave, which has an RMS Voltage 1.4 times that of a sine wave with the same peak voltage. Power is:
V²/R
So (1.4*1.4)² = 2x the power
Think of power as the area under the curve. You can see that a square wave has more area than a sine wave.
So a 500 watt RMS amp could potentially produce 1000 watts RMS if driven to severe clipping. As long as you aren't pushing it that hard, then you're fine.
Here is a really good explanation: http://www.bcae1.com/2ltlpwr.htm
Robby
- Dec 28, 2010
- 357
- 3
- Disclosures
- Art of Noise Audio, fEARful builder
Bill, I'm wondering if the inductance of the woofer's voice coil will roll off the high frequency harmonics caused by clipping, which isn't dissipated as heat.
I'm more familiar with full range systems, so I'm trying to wrap my head around how just a woofer with a natural low pass caused by its coil's inductance would react to clipping.
Robby
edit - I did the math out and with a fully clipped signal that is 1016 Watts, the power under 2500 Hz is still at least 940 watts with anyfundamental under 500 hz, which is about B4.
I'm more familiar with full range systems, so I'm trying to wrap my head around how just a woofer with a natural low pass caused by its coil's inductance would react to clipping.
Robby
edit - I did the math out and with a fully clipped signal that is 1016 Watts, the power under 2500 Hz is still at least 940 watts with anyfundamental under 500 hz, which is about B4.
billfitzmaurice
Commercial User
- Sep 15, 2004
- 16,860
- 278
- 76
- Disclosures
- Owner, Bill Fitzmaurice Loudspeaker Design
Clipping is distortion, but not the only type of distortion.
No. An amp can put out far more than its rated power, which is measured at a low distortion figure, but the clipping does not result in the power increase, the power increase results in clipping.
It does, and that's one of the reason why clipping doesn't hurt woofers.
They can't even post SPL charts and honest specs. You'll sooner see peace in the middle East.
But there's no such thing as a mismatched amp and cab where power is concerned. You can power a 1000 watt speaker with a five watt amp, it just won't go as loud as you might desire. You can power a 5 watt speaker with a 1000 watt amp, so long as you don't turn the volume up beyond where you hear the speaker start to distort. Practically speaking a power rating ratio of 2:1 or anywhere in between, in either favor, amp or speaker, will work just fine.
Some simple thoughts from the perspective of someone (me) with very little sound engineering training/education/understanding:
As long as the resistance ratings are appropriate (you aren't running a 4 ohm amp into a 2ohm configuration of cabs), you can run a 800 watt amp into a cab rated at 500 watts, and you can run a 500 watt amp into a cab rated at 800 watts. You just need to be careful to not unintentionally drive the amp so hard it distorts, or feed the cab so much you damage the speakers.
My combo is 300 watts of amp feeding into a cab rated at 400 watts RMS. If I go above about 3 on the master vol I start farting out the speakers, unless I turn down the lows and go for a more mid range tone.
In my experience, amp ratings often seem "optimistic", cab ratings usually are "optimistic", and common sense separates the bass men from the bass men with blown drivers. The advice others have given about cutting lows or cutting volume to avoid damage, or elevating your cab and aiming it at your head to hear it better, are both GREAT advice.
As long as the resistance ratings are appropriate (you aren't running a 4 ohm amp into a 2ohm configuration of cabs), you can run a 800 watt amp into a cab rated at 500 watts, and you can run a 500 watt amp into a cab rated at 800 watts. You just need to be careful to not unintentionally drive the amp so hard it distorts, or feed the cab so much you damage the speakers.
My combo is 300 watts of amp feeding into a cab rated at 400 watts RMS. If I go above about 3 on the master vol I start farting out the speakers, unless I turn down the lows and go for a more mid range tone.
In my experience, amp ratings often seem "optimistic", cab ratings usually are "optimistic", and common sense separates the bass men from the bass men with blown drivers. The advice others have given about cutting lows or cutting volume to avoid damage, or elevating your cab and aiming it at your head to hear it better, are both GREAT advice.
