Question, 2 amps into 2 cabs @ 8ohms each vs 1 amp into both cabs at 4 ohms?

[dtothec]

[font=]I have a hypothetical question [/font][font=]and something I might try, and you guys are the most knowledgeable on line so I wanted to run this by you all. I have a Streamliner 900 and just purchased a Shuttle 9.0 also 900 watts which I should receive next week. These have the  same amp in them but the preamps are different. I have several Line6 wireless systems and two Fearful 15/6/1 speaker cabinets each 8ohms. Here's my question. If I set up one amp on each of the cabinets, hook up separate receivers to each cabinet, set to the same channel and use one transmitter from the bass set to that channel to feed both receivers.  would I get more volume with each amp pushing 500 watts into two cabinets at 8ohms each, or one amp feeding 900 watts at 4 ohms into both cabinets? I know the amps sound different but just was curious to see if anyone has tried anything like this and which is more efficient (louder clearer etc.) again taking in to account the differences of the preamps?[/font]

[cozmik_cowboy]

Lemme get this this straight - you're talking about running from the amp to the cab wireless?  I think that's, um, how to say it? Not quite the optimal set-up.....

Peter

[dtothec]

I was told to go wireless to one then use the send on it to the receive on the other amp and set the volume on both amps at the same level. My question is with that set up it's running the two amps at 500 watts at 8ohms, and would that be louder than running both cabinets with one amp at 900 watts at 4ohms?

[adriaan]

AFAIK getting a rig to be significantly louder can be achieved either by hooking up more speaker surface to the same amp, or by more than doubling the amp power into the same speakers - all within the boundaries of what the individual components can take, obviously. Setting up a second rig with equivalent amp and speakers will not double your loudness. Hooking up the second cab to one amp will give you a significant increase. And if you want to set up the second rig so the band members on the other side of the stage can hear you better, I'd link up the line-out of the amp you're plugging into to the fx return of the satellite amp. Or you could go bi-amp.

[cozmik_cowboy]

Just to be clear, it sounds like you're talking about running wireless from the amp to the cabs; this will result in an SPL of exactly 0dB. 
If I am misunderstanding, please give us your proposed signal path, step-by-step (i.e., I'm reading your post as discussing instrument>amp>wireless>cab)

Peter

[keith_h]

You should effectively have the same level whether you use one or two amps even though one setup is capable of a combined total of 1000W and the other 900W. It takes 10X (log scale) the amplifier power to double the volume the human ear hears so 100W difference is nothing. For the speakers as they are identical whether run on a single or separate amp the spl will be the same for a given wattage and frequency.
As you mention using separate amplifiers or a single amplifier will likely change the sound you hear and the way you perceive the loudness due to differences in settings and electrical design. My guess is it will be more open and hifi with separate amps and cabinets but not sound as loud based on playing around I've done in the past.

The only thing I'm not sure of is if you could end up with time alignment issues with two receivers. If one is a bit slower than the other with receive processing it could muddy things. I would expect this problem to be non-existent if you use a single receiver and run cables to each amp's input. Of course this would mean the amps would need to be close to each other being high impedance inputs.
 

[lembic76450]

I have a shuttle 9.0 and a 6.2 and find that they both sound very differently
at 4 ohms and 8 ohms.  I would try connecting the inputs with a "y" cord first
to see if you like the 8 ohm sound with each pre amp/amp.  Then try running just the
Streamliner pre running  both amps using the pre out on the Streamliner and the
amp in on the 9.0.  For me, I would just run both cabs off the Streamliner.  I think
you will like the openness of the sound at a 4 ohm load.  Plus, that amp has a great
reputation of tube warmth with the 3 AX7s. Carry the 9.0 as a back up.

[jacko]

Adriaan has answered the technicalities of the question. However, can I just ask 'why bother'?  I went through a period of running two preamps into separate channels of my QSC then into separate speaker cabs.  After I while I got really bored with the faff and went to a single amp.  Like Kenn says, run the streamliner and have the 9.0 handy for when it blows up.

Graeme

[edwin]

I'll go against the grain and say you should run each cab with its own amp. Or at least try it at a few gigs. You'll learn a lot more about it than anything anyone will post here and you'll be able to tell us what you think. Plus, if any other bass player wants to sit in, you'll be good to go!

Edwin
Who, at times, has run a ridiculous number of amps on stage, but still pales in comparison to Bootsy.

[dtothec]

Thanks guys! I have never run the Streamliner at 4 ohms so  I will try that first. I've always used either my svt 4pro or my big rack unit when I had to use two cabinets, but I really like the way the Streamliner sounds. I have several outdoor gigs coming up and I may do some experimenting with the two amps as well!  Edwin funny you mentioned Bootsy,  he lives here in Cincinnati and I do into him every now and then. They were selling one of his Warwick rigs at one of the GC's here about a year ago.