Help with this OHMS LAWW!!! PLEASE!

[AndrewDaBassist]

Hello,

Just to clarify Im a noob at this head/cab business so lets start.

I have a Hartke LH500 which is 500w @4 ohms. I also have a Hartke XL410 cab which is 400w @8 ohms. At my next gig I need to be much louder, and Im thinking of getting an additional Hartke XL210 which is 200w @8ohms. So...

Currently I have:

-Hartke LH500 500w @4 ohms
-Hartke XL410 400w @8 ohms

I just want to add a 410 cab which is 200w @8 ohms.

Would this be safe?? Also would it be loud enough??

Thanks in advance!!!

[BurningSkies]

Thats a bad idea for several reasons.

The most important being that the LH500 is only safe down to a 4ohm load. If you get a 4 ohm cabinet to go with your 8ohm cabinet, your head will turn into a brick.

Second, if you had a head that was safe down to 2 ohms, your 4ohm 2x10 would see twice as much power as your 8ohm 4x10...meaning that those two little 10" speakers are seeing about 4 times as much power as the 4 speakers in the 4x10.

Go and get a second 8ohm 4x10. You'll be much louder and your amp won't die.

Edit: I see you're looking at a 8ohm 2x10...you won't fry your amp, but you will endanger any 2x10 as the two speakers will be seeing as much power as your 4 speakers in your 4x10.

[BillyB_from_LZ]

If you want to connect two 8 ohm cabinets to an amp with a minimum rated load impedance of 4 ohms, you're just fine.

The other thing to consider is that if you use an 8 ohm 410 and an 8 ohm 210, the 10s in the 210 will be receive twice as much power as the 10s in the 410. Probably won't be an issue, but it's something to think about.

[BassmanPaul]

Originally Posted by BillyB_from_LZ

The other thing to consider is that if you use an 8 ohm 410 and an 8 ohm 210, the 10s in the 210 will be receive twice as much power as the 10s in the 410. Probably won't be an issue, but it's something to think about.

Yes it WILL be an issue Billy! Two 10" drivers simply cannot do the work of four 10" drivers. The cabinet WILL eventually fail.

[BillyB_from_LZ]

Originally Posted by BassmanPaul

Yes it WILL be an issue Billy! Two 10" drivers simply cannot do the work of four 10" drivers. The cabinet WILL eventually fail.

OK, I stand corrected...

[dmusic148]

Best bet is a second, identical 4x10.
Next best is a 2x10, 4 Ohm model. Rewire it so the speakers are in series(16 Ohm). The two cabs connected to your amp will present a 5.3 Ohm load and all the speakers will get the same power.

[RickenBoogie]

+1 to that^.

[morgan138]

Originally Posted by dmusic148

Best bet is a second, identical 4x10.
Next best is a 2x10, 4 Ohm model. Rewire it so the speakers are in series(16 Ohm). The two cabs connected to your amp will present a 5.3 Ohm load and all the speakers will get the same power.

Exactly. And as a bonus, giving your head a 5.3 ohm load instead of your current 8 ohm one will get it closer to its maximum 500 watts power output. Because right now I'd guess you're getting something like half power out of that amp.

[krstko]

Get another 410xl ..it's cheap if you can get it used, you will have normal 4ohm, you won't fry any cabs,...

[Downunderwonder]

Originally Posted by dmusic148

Best bet is a second, identical 4x10.
Next best is a 2x10, 4 Ohm model. Rewire it so the speakers are in series(16 Ohm). The two cabs connected to your amp will present a 5.3 Ohm load and all the speakers will get the same power.

Yes

Caution, 2x10 16 ohm will make it louder, but only a little louder. It will get speakers up closer to your ears so you will get a better earful but total volume increase is only about 3 dB.

You can hear 3dB difference here:

Audible Difference in Sound Level Blind Listening Test

Hit "change target" to 6dB to hear what adding another identical 4x10 does. Significant increase.

option 3: get a PA

[krstko]

Originally Posted by Downunderwonder

option 3: get a PA

+1

btw what kind of gig is this, I have exactly the same amp/cab and I giged in open space to 300-400 ppl .. I had it at about 1 o'clock .. anything bigger than that should have a PA support (and you do have a PA out)

[Bassamatic]

Yes, Ohm's Law can be confusing because adding can result in a smaller number. Remember that in ANY parallel combination of speakers, the total impedance will always be less that of the lowest impedance speaker. i.e., 4 +4 = 2 Ohms, 4 + 8 = 3.2 Ohms, etc.

Think of it as adding more hoses to a water outlet. Even adding the smallest hose will increase the water flow, increasing the total current. 2 hoses of the same size double the current. If you draw too much current from amp you can damage it.

[Ric5]

Originally Posted by AndrewDaBassist

I have a Hartke LH500 which is 500w @4 ohms. I also have a Hartke XL410 cab which is 400w @8 ohms. At my next gig I need to be much louder, and Im thinking of getting an additional Hartke XL210 which is 200w @8ohms. So...

Currently I have:

-Hartke LH500 500w @4 ohms
-Hartke XL410 400w @8 ohms

I just want to add a 410 cab which is 200w @8 ohms.

Would this be safe?? Also would it be loud enough??

The ohms load would be 4 ohms which is good. (2 - 8 ohm cabs in parallel = 4 ohms) Just don't turn up too loud otherwise you will blow the 200w cab. But because you are doing this to get more volume you are at risk of blowing speakers in the 200W cabinet.

It sounds like you need PA support.

All you guys need to realize the LH500 is the bass head!!! Many of you assumed it was a cabinet ...

So what we have is a 500w head and 2 4x10 cabs at 8 ohms each. total load = 4 ohms.

[Downunderwonder]

Originally Posted by AndrewDaBassist

-Hartke LH500 500w @4 ohms
-Hartke XL410 400w @8 ohms

I just want to add a 410 210 cab which is 200w @8 ohms.

Would this be safe?? Also would it be loud enough??

Thanks in advance!!!

210 I think you meant there? That's definitely unsafe for the 2x10.

If you wind it up to the 210 getting its maximum power, the 4x10 is getting half power it was getting before you added the 2x10, so you get almost no volume increase.

You're thinking "how can this be? I paid good money for an extra cab!" So you push the 2x10 into destruction trying to get your money's worth from it.

[Ric5]

A good addition would be a 500w 8ohm 1x18 cabinet.

[onosson]

Why not just trade in your 8ohm 410 for a 4ohm 410? I ran my LH500 into a 4ohm eden 410 and never lacked for volume in any situation.

[Downunderwonder]

Originally Posted by onosson

Why not just trade in your 8ohm 410 for a 4ohm 410? I ran my LH500 into a 4ohm eden 410 and never lacked for volume in any situation.

That gets him 3dB. More speakers always wins.

I'd like to know why the existing rig isn't loud enough. It's freakishly loud already.

[onosson]

Originally Posted by Downunderwonder

That gets him 3dB. More speakers always wins.

I'd like to know why the existing rig isn't loud enough. It's freakishly loud already.

Sure, but 3db isn't nothing either, and he doesn't have more gear to haul around if he gets a more powerful cab. Just an option. 500W through four 10" speakers has always been plenty for me, even for outdoor festivals and arenas. YMMV

[Ric5]

I have 3 ampeg bass heads that can all be run at 4 or 8 ohms. I have 6 speaker cabinets that are all 8 ohms. 3 cabs are 2x10s. The 2x10 have 2 16 ohm 10" speakers run parallel which makes them 8 ohms. I have 2 1x15 cabs. This is easy I just put 1 8 ohm speaker in each. I also have a 1x18 cab that has an 8 ohm 18" speaker in it.

So what do I do if one amp and 2 speaker cabs aren't enough? I run a preamp out of one bass head into a line in on the next head which bypasses the front controls and makes the second amp a slave to the first.

I can then run all 3 amps and all 6 cabinets.

But with pa support I find one amp with two cabs is plenty.

[tjh]

Keep it simple ... get another 410XL used, they are cheap and readily available used ... they can be found nearly for the price of a 210XL ...

... besides, if you like your sound, the 210XL will be different, as it is a sealed cab, whereas the 410XL is a ported cab