Ohms and wattage...

[lemongonggong]

Hy guys, need some help here?..

Would it be okay to power a Hartke 210XL cab (200 watts @ 8 ohms) with a Markbass little mark tube (300 watts @ 8 ohms, 500 watts @ 4 ohms)? What about at full volume?

I been reading up on all this ohms and watts thingy and i still dont really understand...

Raymond

 

[alanchia]

yes you can, provided you dont drive the cab at higher volumn which is exceeding 200W (which is what it is capable of).

is this setup for your practise or for live performance? i am not so worried if it's for practise as bassists dont usually need that high power unless you have the priviledge of having your own studio. am more worried for live as you may need high volumn for the hall to get the bass through.

 

[Resetti]

it's dangerous.

the speakers is rated 8 Ohms and can take only 200W at this rating.

you mark bass head can give out 300W at 8 Ohms rating.

this means that there is potential to overload the speakers and spoil it if you're turning it to full volume. actually no need full volume, i think if you turn the volume to to 5/10 it's already dangerous.

 

[alanchia]

agree with what resetti said. the issue is how much volumn is being turned up. that's why i said provided you dont drive the cab at higher volumn which is exceeding 200W.

so, let me emphasize my post to threadstarter again:
if you potentially will be playing your bass with loud volumn (which is very typical for live performance), i'll suggest you to get a cab with higher power handling (anything 300W or higher is fine) since the amp is 300W. if you are using it as practise amp at home (let's say HDB), 100W power is very loud as it will rock the house. lol

just in case you get confused with power rating. these amps are rated at RMS (root-mean-squared). most consumer home hi-fi are rated PMPO (peak music power output). i may be wrong, RMS 100W should be able to deliver PMPO 1000W. i am sure you dont turn on your home hi-fi volumn at 1000W.

 

[dumbcube]

Just run an extra cab in parallel with headroom 300 watts or higher to compensate. That'll ensure u wun bust ur cabs.

 

[lordie]

what abt the other way round a 500 watts @ 4ohms thru a 4x10 cab rather at 1000 watts @ 4ohms?

 

[alanchia]

Just run an extra cab in parallel with headroom 300 watts or higher to compensate. That'll ensure u wun bust ur cabs.

true, but in that case wouldnt buying just one cab handling 300W be more feasible?

 

[Tetragrammaton]

Ok...just to give a simple understanding about Watt and Ohm. Ohm is the amount of resistance, example if your speaker resistance is 8 ohm and your amplifier down is for example 6 ohm. So there is a difference in 2 ohm from the mainstream hence then your speaker won't be running optimum. Just like in piping a 6 inch pipe supplying to an 8 inch pipe, the result is the water pressure will be lesser on the other end of the 8 inch pipe.

Watt on the other hand the amount of power output or power input acceptable. If your speakers are made to withstand 200W, running an amplifier higher then the acceptable wattage is not advisable as it may damage your speakers. Just like in piping, your pipe can withstand 200psi in pressure but your water pump is running down at 500 psi for instant. The result is your pipe will burst.

This is how on electrical terms one may understand further.

Saluti!

 

[alanchia]

great job! wonderful and yet easy to understand illustration.

 

[shinobi]

sorry guys, just to clarify, i don't really bother about what the theory says but in reality, it's not possible to destroy speakers just because you are using an amp that has a higher wattage than the wattage rating on the speakers.

the wattage rating is not an indication of what the speaker can handle. it is an indication of what the speaker can produce. in the case of 300W amp driving a 200W speaker, the speaker isn't capable of running 300W. period. all you are ever going to get from the cab is 200W, so the amp is never gonna destroy the cab that way.

the analogy with the pipes helps us understand what happens when the resistance of the cab is higher than that of the amp, but it doesn't explain the consequences of when it is lower.

the resistance rating on the amp refers to the maximum load that the amp can handle. the resistance rating on the cab refers to, well, the resistance of the cab. the resistance of the cab should never be lower than the minimum resistance rating of the amp. when an amp says something like 500W @ 4ohms, 300W @ 8ohms, it usually means that 4 ohms is the MAXIMUM load that the amp can handle. anything more than that (ie lower resistance) and you will damage the amp, not the cab.

the only way that the cab can blow is if the output (loudness) is more than what the speaker can handle. if you encounter enough amps you will realise that even at the same power rating, some amps are louder than others. different amps also have different capability of running at maximum performance. it don't think there is an amp out there that will necessarily become louder when the gain is at 100%, the amp is bound to distort.

it is possible that you can blow a speaker if you crank an amp that has a power rating that is higher than that of the cab, but it is not necessarily the case. if lets say your bass has a hot active preamp, or if you are running a boost or OD in your chain, different amps may have different amounts of headroom, even at the same wattage rating. so even if your amp is perfectly matched to your cab, it is still possible to blow the speaker.

 

[alanchia]

a good reading article is found here
http://www.jblpro.com/pub/technote/spkpwfaq.pdf

 

[dumbcube]

true, but in that case wouldnt buying just one cab handling 300W be more feasible?

True. But more speakers pushing more air for more volume, why not since he already has a 200watter? Hehe. Loud is good.

 

[lordie]

so meaning a Eden WTX500 pair with a D410 will spoil the amp if we push the amp hard? like 50% thru?

 

[alanchia]

typically we should try to match amp power to speaker handling.

if you've read the jbl article (and there's also a similar article from hartke), you can drive a cab with lower power handling than what the amp can produce (hartke quoted a 1000W amp driving a cab (AK series) capable of handling 500W).

 

[lordie]

the WTX is 500watts at 4ohm and the cab is 1000watts at 4ohms

 

[lemongonggong]

this setup's for both practice and performance

So it looks like i need to get an bass cab that can handle 300 watts at 8 ohms..any suggestions from u guys?