Double Bass 4 ohm vs 8 ohm

[Ruuumble]

Oh Rustyaxe - is that from 1001rb mark1? I have mark II it says 700w + 50w horn into 4 ohms - it just doesn't say what it is into 8ohm

 

[RustyAxe]

Oh Rustyaxe - is that from 1001rb mark1? I have mark II it says 700w + 50w horn into 4 ohms - it just doesn't say what it is into 8ohm

Opps, wrong specs altogether. Lousy website organization! Poor reading on my part. Here's the 1001rbII ...

1001RB-II 460W @ 8 Ohms
700W @ 4 Ohms

As it takes a doubling of power to get a +3db gain ... so still a relatively insignificant difference in volume in comparison to the difference between cabs and speakers.

 

[drurb]

The best thing you can do for yourself now is to disassociate volume and watts. They have little to do with each other.

Indeed. Now where have I heard this before?

...I definitely noticed that my Eden Metro run at too low of a master volume, usually w/ a 4 ohm load, would not be as "open" or "dynamic" as if I could run at 8 ohms and turn the master volume up some.

This likely had nothing to do with the change in impedance, per se.

From the GK1001rb manual specs:

540W Amplifier 540W @ 8 Ohms
540W @ 4 Ohms
50W Amplifier 50W @ 8 Ohms
50W @ 4 Ohms

Even if this is a misprint, in most amps the difference in output at 4 vs 8 ohms is negligible ... in the order of 1 or 2 db or less.

First of all, GKs aren't the only amps out there. Second, keep in mind that 3 dB corresponds to a doubling of power!

 

[Ruuumble]

Opps, wrong specs altogether. Lousy website organization! Poor reading on my part. Here's the 1001rbII ...

1001RB-II 460W @ 8 Ohms
700W @ 4 Ohms

As it takes a doubling of power to get a +3db gain ... so still a relatively insignificant difference in volume in comparison to the difference between cabs and speakers.

Yep point well taken - the old law of 10's and 3's!
Additionally I know that +3db of power does not translate into double audible level either
It's not power that is the original question- I was wondering if there is a perceived tonal difference between a 4 ohm load w volume turned way down or into an 8 ohm load turned up and being able to really 'drive' the amplifier
I don't have a similar 8 ohm cab to compare apples to apples
However I will say that my bass /pu /amp have enough signal w/o a pre but I use a pre to drive the front end a lil more and to me sounds much better even if the overall volume is down.

 

[drurb]

Additionally I know that +3db of power does not translate into double audible level either

If you're referring to loudness, listeners judge a sound to be twice as loud when its sound pressure level is increased by approximately 10 dB. That's a ten-fold increase in power.

 

[JP Morin]

interresting discussion !!!

I don't know a lot about these rules... so may be i'm wrong again, excuse me if it's the case !!! Just trying to understand all those things... lol

But I know you can have SWR's Goliath cabs in 8 ohms and in 4 ohms

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They are surely similar in design, the speakers seems to be the same in both and the speakers should be wired differently, I think, to achieve different impedence...

But what would be the difference in sound between these two cabs, having the same wattage applied to them ?? I've never A/B compared both... just curious about how the speakers would react differently if they would...

 

[drurb]

interresting discussion !!!

I don't know a lot about these rules... so may be i'm wrong again, excuse me if it's the case !!! Just trying to understand all those things... lol

But I know you can have SWR's Goliath cabs in 8 ohms and in 4 ohms

Invalid Link Removed

They are surely similar in design, the speakers seems to be the same in both and the speakers should be wired differently, I think, to achieve different impedence...

But what would be the difference in sound between these two cabs, having the same wattage applied to them ?? I've never A/B compared both... just curious about how the speakers would react differently if they would...

Wattage isn't really "applied" to a cabinet. Rather, the power amplifier acts as a current source such that when a voltage is applied to the cab, provided the amp can supply the necessary current, a given amount of wattage ends up being developed/supplied.

Now, assume one really had two cabs with functionally identical speakers, save for their voice-coil impedances and that those cabs each had the same ratings in terms of the sound-pressure level developed for a given wattage. In the case of the 4-ohm version, the amplifier would be called on to produce twice as much current as in the case of the 8-ohm version. Assuming that was within its capabilities and forgetting about any secondary effects, one would not expect the two to sound any different.

 

[JP Morin]

Many thanks for your replies !!!

That explain the fact that when I tried some cabs when I bought my kit, the 4 ohms cabs seems to have more punch than the 8 ohms... the head, by it's design, was giving more power to the 4 ohms (ampeg svt-3pro)... Well... Ill go to bed tonight a little less noob than yesterday... lol

 

[drurb]

Many thanks for your replies !!!

That explain the fact that when I tried some cabs when I bought my kit, the 4 ohms cabs seems to have more punch than the 8 ohms... the head, by it's design, was giving more power to the 4 ohms (ampeg svt-3pro)... Well... Ill go to bed tonight a little less noob than yesterday... lol

Nope, that's not the case at all if both are adjusted for the same output level. All other things being equal, you'd likely be able to get a greater overall level from the 4-ohm cab but when adjusted to the same level, the 4-ohm cab wouldn't be expected to have more "punch" than the 8-ohm cab. Of course, all things are rarely equal. If you heard more punch from the 4-ohm cab(s), it was likely a result design differences as compared to the 8-ohm cab(s).

 

[JP Morin]

ok thanks !!

 

[Gary Lynch]

My head always hurts when I read so much information but it is useful. I use the Doubler into either a 4 ohm 12" Whizzy or the EA 4 ohm 2x10 and I'm really happy I do not have to search further. These do all want and/or need. My theory was as you folks have stated, get the most from the Doubler using 4 ohm cabs. Thanks for posting this information.