When purchasing an amp, always apply ' safe math '.

If your speakers can handle 120 watts, use a 100 watt amplifier. NEVER go over the ratings of the total consumption the speakers can handle.

Some will say underpowering speakers will cost you ' quality ', not always true.

In my guitar rig, I have 4 4x12 enclosures. Each cab has 4 ' greenback ' speakers rated at 30watts. Each Cab can handle 120 watts, yet I only power them with 50 watts.

The ' mains ' on my JBL P.A. can handle 2800 watts on the bottom end and 1700 on the top. I might use HALF of what they can handle.

No noise, no blown speakers/horns, no worries.

Higher wattage ratings don't really mean a thing. 50 watts of A/B Tube to that 4x12 Marshall cab for my guitar will totally drown out some of these alledged SPL/Competition audio car setups claiming to have millions of watts.

 

Maybe in the 50's and 60's but not in the present. There are dual rectification setups now and signal tone and the amplifying power section are totally different entities.

A JBL JXR115 enclosure uses the same 15inch speaker that folks use in their car audio setups. The same with EVM and EVX speakers.

Yeah.. its on the internet, it must be true.

I wonder if the folks at Crutchfield ever play with setups like this -- >
https://www.carvinguitars.com/produc...uct=TRX153-44T

 

I unnderstand what your saying, and its different applications. My experience is with REAL avenues of ' live sound ' and recording.

Honestly, Car audio is a dime a dozen to me. I'm not ' downing ' it, its just boring for myself. Just replication of someone elses goods/sounds.

What your leaving out of the equasion is ' headroom '. At a MINIMUM I run a 15-20% headroom so theres no chance at popping a 500-1000$ speaker or horn. Feedback from mic gain is the most damaging entity in itself. ( car audio has no such worries though )

Carvin, Behringer and Ashley all have limiters/band-pass filters in their amps, no chance for a Squarewave what-so-ever.

Good show ! ( agreed ) .

That would NEVER happen in any rig I setup. Thats just asking for trouble.

This might sound rude ( I'm being 100% honest in asking ) , but is car audio that far behind live audio? My monitor amp is an OLD Ashley, Its FET driven, and it even has a limiter and a clip in it to prevent such.

Actually, channel 54 on my JBL rig has an Insert with a balanced xlr that goes to an older iMac to run iTunes between sets. Theres NOTHING like 8 18inch JBL's pushing 3000watts a side in W-Wedge Cabs rumbeling a building. My guitar amp isn't a ' full range ' rig. Actually It has a high and low pass filter set at 100hz and 8khz. Being a 440-A tuned instraument, there are frequencies never used by a guitar as ( harmonically ) it cannot go down that low nor up that high in frequency. It wouldn't work, parts of a song or certainn instrauments won't ' come out '. But through the crossover in the mains, it comes out nicely.

DBX Drive-Racks are nice :)

True. But P.A. Systems use common ' loud speakers '. In a live performance, nobody needs 50stack amps behind them. I take all 4 of my cabs but 3 are for show, only 1 is producing sound/is hooked up. I let the Mains do all the work. Things get too noisy on stage and people can't hear one another.. 50 watts of A/B rectification against 10K+ of P.A. system.. iI would have better luck with a Louisville Slugger against an M1 Abrams tank.

You don't believe such would be bad for a speaker and cause cone failure? or burn the coil?

If someone needs something THAT loud, they should buy GOOD speakers and amps so it would be reliable at certain levels and no risk would be taken.

Then again, I have seen live rigs for main acts fail and leave a band hanging.

Yep.

My brother has been running live sound for the last.. 30ish years. He owns a studio and spends about 6 months a year on the road for country acts. Brooks and Dunn, Blackhawk ( those guys are alright! ), Tanya Tucker a few years back, Clint Black..

Crutchfield might know something about car audio, but they don't know a damn thing about ' big rigs '. Maybe Car-audio and Live rigs are ' different animals ', but I find it odd that the SAME speakers are used in a lot of setups. Porting, enclosures, materials.. all quite common.

Usually when testing a new amp that comes in ( Yes, Carvin amps DO go! They go BOOM too! ), it gets put on a bench with a ' load '. The amp is then ' run up ' and ' burned in ' for a 6-8 hr period and checked for power levels to make sure they are within specs so theres NO CHANCE of wasting a cab during a performance. Sure, a spike might happen, but its very rare when all the juice is run to a Furman ( usually an M-8L ) or a ' Juice Goose '.

Are car audio amps factory tested as such or is it ' buy and pray '? Does car audio even have set ' standards '? It sure doesn't sound like it or they are trying to do something ' different ' then whats been done for many years.

 

Theres 3 different power ratings. ' Peak ', ' Peak to peak ' and RMS ( root-mean-square ).

In a power band ( full wave ) , ' peak ' is the value from the highest point to ' 0 '. ' Peak to peak ' is a full wave reading that measures the highest to absolute lowest value. RMS is a ' peak ' value times ( multiplied ) by 0.707 .

100 watts peak power = 200 watts peak-to-peak ( usually ) = 70.7watts RMS.