4 ohm vs 8 ohm

pickups · #1 04-18-2011, 09:42 PM

About to order an Aguilar AG500 head which is 250 watts at 8 ohms and 500 watts at 4 ohms. i don’t plan on ever using more than one cabinet but you never know when that might be a good option one day. Im worried about not having enough power with 250 watts at 8 ohms. will a 4 ohm cab (Aguilar GS410’s) make that much of a difference than an 8 ohm cabinet? 500 watts vs 250 watt? i think the amp would run more efficient on a 4 ohm cabinet but if the sound isn’t that much louder i might as well just get the 8 ohm in case i ever wanted to one day use another cab with it. any thoughts would be much appreciated. thanks

Downunderwonder · #2 04-18-2011, 09:58 PM

Yes, the extra watts are barely any louder by themselves with a single cab. But two cabs kicks arse.

96tbird · #3 04-18-2011, 10:24 PM

Volume has more to do with how many drivers you have than wattage. At least past a certain point. Lots of guys here know exactly how much,not me, but 500 watts will only add something like 3-4 dB loudness over 250 (guessing, but not too far out I think). Brain instantly melting vs. brain exploding. But if you have a cab with 4 drivers versus 2 you will move more air, see? I would go with the 4 drivers if using one cab 8 ohms, Aguilar has em. Then you can expand. And i'm sure those cabs are plenty efficient enough to get the most out of watts in. The Aguilar site shows you that 4 or 8 ohms, the sensitivity (efficiency) is the same. But i'm no audio engineer to speak on efficiency claims. Both are enough to ruin your hearing permanently.

pickups · #4 04-18-2011, 10:33 PM

Thanks folks for your input. i think i will go with the 8 ohm. i would like to keep my options open and if its not that much louder it seems like a win win. thanks

Selta · #5 04-18-2011, 10:43 PM

500w versus 250w... In theory, you'd gain about 3dB. In real application, not so much.

You'll gain more volume by adding speakers than you will by doubling wattage.

TL;DR: get the 8 ohm cab

Edit: Also, the amp likely isn't more "efficient" at the lower impedance. In fact, it's working harder.

OOZMAN · #6 04-18-2011, 10:50 PM

Yeah, 8 ohm.

pickups · #7 04-18-2011, 10:55 PM

Thanks man you guys know way more than i do about this stuff. i’ve been playing the same swr workingman 112 combo for 10 years so i have not had any reason to learn this stuff till now that its time to get another amp. thanks

Downunderwonder · #8 04-19-2011, 12:27 AM

Have you tried the new gear before ordering it? You might get a shock as to how little extra you get from it compared to the SWR. Watts by themselves are extremely poor indicators of loudness.

For instance, my 50W valve amp is damn near giggable with drums, my 300W per channel power amp isn't as balsy as my 250W Trace head.

You might look at a tower of two 2x10 cabs for bigger bang per buck, better fidelity. It's the new 4x10.

pickups · #9 04-20-2011, 12:30 AM

yeah i thought about that but was worried i wouldn’t get the fullness i would out of 410’s?

JimmyM · #10 04-20-2011, 12:55 AM

Quote:

Originally Posted by pickups

yeah i thought about that but was worried i wouldn’t get the fullness i would out of 410’s?

any time you can use a larger rig, you're better off if you're looking for fullness. the 410 tower has advantages in dispersion of highs and mids, but the extra 4 speakers of the 810 definitely add a layer of warmth you don't get with the 4 10"s. however, a 210 vert stack does kick ass over a 410 imho.

OOZMAN · #11 04-20-2011, 11:43 AM

Quote:

Originally Posted by JimmyM

any time you can use a larger rig, you're better off if you're looking for fullness. the 410 tower has advantages in dispersion of highs and mids, but the extra 4 speakers of the 810 definitely add a layer of warmth you don't get with the 4 10"s. however, a 210 vert stack does kick ass over a 410 imho.

...and it'll kick your ass when it falls over on ya.

Downunderwonder · #12 04-20-2011, 12:35 PM

Some 2x10 are skinnier than others. I wouldn't have a problem with two SWR jrs, only 1/2 "taller" than it is wide and deep. Two of them would be 3 to 1 in aspect.

cavedweller · #13 04-20-2011, 09:57 PM

Quote:

Originally Posted by JimmyM

any time you can use a larger rig, you're better off if you're looking for fullness. the 410 tower has advantages in dispersion of highs and mids, but the extra 4 speakers of the 810 definitely add a layer of warmth you don't get with the 4 10"s. however, a 210 vert stack does kick ass over a 410 imho.

so...there is a noticable difference between 2 410's stacked and an 810?

GrowlerBox · #14 04-20-2011, 10:33 PM

Quote:

Originally Posted by cavedweller

so...there is a noticable difference between 2 410's stacked and an 810?

No, Jimmy's comparing a pair of vertically stacked 210s with a 410 or an 810 (or 2 x 410s); better all round than the former, better dispersion than the latter, but less loud (at least down low) and (?therefore) less warm.

JimmyM · #15 04-20-2011, 11:02 PM

'zacly!

Plstrns · #16 04-20-2011, 11:11 PM

I was going to build a pair of 210's based on the Ampeg 810- 4x 210's stacked dimensions using the Eminence 32 ohm SVT replacement speakers then stack'em vertically. VT pedal & 4-600 watts should be as good as it gets, and very nearly as loud as a dimed SVT/ 810 rig.

But, this Greenboy guy...

OOZMAN · #17 04-21-2011, 01:42 AM

^*doubtful emoticon*

dave2 · #18 04-21-2011, 02:19 AM

I would love to have two 4 ohm GS410 cabs stacked!