Bass Amps... What configuration with my Rics?

[Low End Lover]

Hey Rickers,

So as some of you know, I have a 1/2010 4003 & a 7/2008 4003FL, both strung with Fender 9050CL's Flats. I love these basses and feel like I have finally got my "basses covered".
With this settled, I want to turn my attention getting a good amp setup. I have a '99 Ampeg RocketBass combo @100W, which I like a lot, but I need more power as I am starting to play with folks more. I have done a good bit of research and I think I have settled on Genz Benz gear. My question is about what configuration to get? If things go really well gigging-wise in the future, I could be playing small outdoor gigs or, at best, a 500 person club. I was looking at the ShuttleMAX 6.0, which is 600W output with the right cab, which I assume would more than enough. In terms of cabs, this is where I get confused, e.g 2x10 vs. 2x12 vs. 4x10. Also 4 ohm vs. 8 ohm and why that matters. (Regarding the ohm question, I have NEVER run across an answer that didn't require a degree in EE to understand!) I have spent a lot of time looking online and most of the explanations are so techy that they are all but useless to me.
The type of music I dig is rock, a lot of 60's stuff, e.g. psych and garage, indie rock, e.g. punk, early r.e.m./jangly pop/rock stuff and traditional jazz with the fretless. I play with a pick and my fingers, but I am not, nor will I ever be a slapper & popper. With that in mind, I am just not sure the best cab for me and my Rics. I would only get one cab. I know I want something that will be tight, clear and punchy.
Hopefully, based on what I have said above, this can give the more knowledgable amp folks on here enough info to make some suggestions. And, as always, if you need more info. from me, please ask.

Thanks for the help,

LEL (Jason)

[Fretjob]

Hi resistance speaker - 8 Ohm, takes more power to make it work.
Lo Resistance speaker - 4 Ohm, takes less power to make it work.
(Someone may say why 4 is better than 8 or vica better, but i have never bothered or even recognised that this matters)

As the Amp has to work harder (or less) to make each speaker type work the available wattage from the amp changes. In your case
e the 600 amp specs are

375W @ 8 ohms
600W @ 4 ohms

So, if you get 4 Ohm speaker, you will have to have a speaker rating of around 600W if the cab is 4 Ohm, or 375 W is the Cab is 8 Ohm.
If you are thinking of hooking up two cabinets, things get a little more "complicated", but lets take it one step at a time on that front.

On gigging, if you were playing a 500 person gig, i really doubt your amp will be the main source. You will be playing through a PA with the amp only for your own personal benefit and stage monitoring.

IMO, anything 500W or above will cut it for any "normal" small band gigging situation. I have a Hartke 7000 which with the right speakers could hold it's own in a small village hall in a rock covers band. I've seen players play through really small rigs in large halls, but it does depend a lot on the loudness of the other band members. Metal Band or Ceilidh band.

If you are only looking at one Cab and want tight, clear and punchy, i'd go for 4x10 or 2x12. Doubtful you'll get a 2x10 that can handle the power from that amp.

[iamthebassman]

I use my Ampeg Rocketbass for every show; theatre, outdoor festival, baseball stadium, club, etc. Why would you switch?

[cjj]

Hi resistance speaker - 8 Ohm, takes more power to make it work.
Lo Resistance speaker - 4 Ohm, takes less power to make it work.

Well, first off, that statement is wrong, but it points out just how confusing this subject can be. This does get a bit technical, because it's a technical subject, but I'll try to keep it reasonable.

First off speakers have a power rating. This tells you how much power a speaker can handle. A 200 watt speaker can handle 200 watts regardless of whether it is 2 ohm, 4 ohm, or 50 ohms. What does change is the amount of current it takes to drive the speaker at a given power. A lower ohm rating will take more current than a higher one.

Why? Well, (and we get a bit technical here) power, in watts is given by the following equation with respect to resistance (ohms) and current (amps, usually denoted with the letter I):

P = (I * I) * R or sometimes called "I squared R"

So, if R goes down in value, I has to go up in order to get the same value for P.

Mostly, what ohm rating you pick depends on your amplifier (you don't want to hook something up that's outside the range it can handle), and how you want to configure them. With a single speaker cabinet, it's not a huge deal, but if you want to have the amp drive multiple cabinets, it can become a problem.

In general, if your amp has more than one output, they are connected "in parallel" which means that both speaker cabs are connected to the same circuit side by side. When this happens, the effective resistance goes down and for the same output power, the current required will go up (remember from above?). It's easy to go beyond the output current rating of the amp by doing this and cause the magic smoke to be released, rendering the amp useless.

Now, the statement about the amp working harder with a lower ohm speaker is kind of true. As I said above, for lower ohms, the amp has to pump out more current, but not necessarily more watts, so it isn't really "working harder", just at a different operating point. Amps also have a rating on how many volts they put out. Volts, amps, resistance, and power are all related. Power in watts can also be described by:

P = V * I or current times voltage

And voltage with respect to resistance and current can be given by

V = I * R

So, with those equations and some simple algebra, you can come up with this:

P = ( V * V) / R or V squared divided by R

Now, you can figure out anything you want. But why? It really doesn't matter for this discussion, I just wanted to mention those to answer the difference in output power of the amp when you use different ohm ratings for the speaker.

The amp can only put out a certain maximum voltage based on it's internal power supply. It can actually drive current at that voltage at any level up until it smokes. So, at the maximum voltage, for some value of speaker resistance "R", the power that the amp can put out will depend on the value of R. If R goes down, the power will go up (and so will the current as shown in the beginning).

That's why the amp can only do 375W into 8 ohms. The power is limited by the maximum voltage output rating of the amp. With 4 ohms, at the max voltage, it can get up to 600 watts by pumping out more current. If you go to an even lower ohm speaker, the amp will put out still more current and of course more watts, but at some point, you'll fry things because you go beyond what the amp can handle and again, the magic smoke is let out.

So, hopefully, that didn't get too technical (yeah, I know it did, but as I said, it really is a technical subject). Do you need to know this? probably not as long as you stay within the range that the amp can handle. As I said before, you only get into trouble if you combine speakers. And there's more math involved there as well as understanding series vs. parallel connections. I won't go into all that, but just say that in series, the speaker resistance just adds. In parallel, total resistance is given by adding 1/R for each a speaker and then inverting (1/number) the result:

Rt = 1/((1/r1) + (1/r2) +...)

so for equal value speakers, say 8 ohms, 2 of them will cut the total R in half:

Rt = 1((1/8) + (1/8)) = 1/(0.125 + 0.125) = 1/0.25 = 4 ohms

Hope that helps...

[teeder]

To sum that up: You should probably get the amp head you like and add a 4X10 (4 ohm) cab to keep it simple.

[cjj]

To sum that up: You should probably get the amp head you like and add a 4X10 (4 ohm) cab to keep it simple.

Yeah, probably.

But, we could go into a discussion of 10" vs. 12" vs. 15" and 1 vs. 2 vs. 4, etc. Just for a bit.

Bigger speakers move more air when the cone moves. This is, in general, good for bass frequencies because it takes a lot of air movement to get those low frequency sound waves moving with sufficient intensity to be heard.

So, one would think that bigger speakers are better, right? Well, there's a problem here too. Bigger speakers can't change direction as fast (this has to do with inertia and other junk you learn in physics, but...), which means they can't do high frequencies nearly as well as smaller speakers. So, how can you make a small speaker move as much air as a big one? Put a bunch of them together and have each one move part of the air so that when added together, you get lots of movement at those low frequencies!

That's why a 4x10 can sound good and loud at low frequencies and also have a good range at higher frequencies too. The big 15" will start to lose out when you get up in frequencies.

So, what do you get? Well, it's largely a matter of what sounds good to you and your style. If you want a lot of mids and highs, get something with multiple smaller speakers. If you want big low end thump, get big speakers. The smaller ones can also do the low end, as long as there are enough of 'em, but might let through mids you don't want.

Of course, with all the EQ stuff they put on amps these days, you can tune out a lot of stuff you might not want, so it just gets more complicated. And then, the actual construction makes a lot of difference too. Brand A's 4x10 will likely sound different than Brand B's, so you really need to go out and try a few different types/brands to see what you like.

But, a 4x10 cabinet is a good place to start...

[FretlessOnly]

A 4x10 is a great place to start, and although I really liked the 4x10 sound for years, I now much prefer the sound of my 2x12, even though it does move less air. The issue with getting a 4 ohm 4x10 as a place to start is that the inevitable course of action is to perhaps add a 1x15 down the road. But since the 4x10 is 4 ohms, odds are you won't be able to add that 1x15 due to impedence mismatches.

So Jason, my question to you is this:

Are you 99% sure that you only want one cabinet and you will have no plans to add a second cabinet in the future?

If one cabinet is all you'll ever want, then get a 4x10 or a 2x12 at 4 ohms. If you think you may want that second cabinet at some point, get the first cabinet at 8 ohms. Later, you can add a second cabinet (in whater speaker configuration you choose) at 8 ohms. Running two cabinets at 8 ohms in parallel creates a 4 ohm system, so that second cabinet adds speaker area and typically increases your overall wattage by 50% (now split between the two cabinets). Just be sure that your head has two speaker outputs!

Of course, buying that second cabinet allows you to consider a second head so you can run RIC-O-Sound, which is always a good thing! It's all about options and whether you think you need them.

[Fretjob]

Hi resistance speaker - 8 Ohm, takes more power to make it work.
Lo Resistance speaker - 4 Ohm, takes less power to make it work.

Well, first off, that statement is wrong, but it points out just how confusing this subject can be. This does get a bit technical, because it's a technical subject, but I'll try to keep it reasonable.

True, i wasn't actually meaning electrical Power, but rather an analogy to help him get his head around the amp wattage ratings. More resistance, less available amp power.

[Low End Lover]

I use my Ampeg Rocketbass for every show; theatre, outdoor festival, baseball stadium, club, etc. Why would you switch?

The folks I play with can get loud and I need something with more power. Also, I have tried a ton of basses over the years, but never fussed with amps as I never really gave it much thought. Now, I am wanting to try something new. For example, I never looked past Fenders for years, but then I tried a Ric and it changed everything for me basswise. That all said, I love my RocketBass and have no plans to sell it.

Mostly, what ohm rating you pick depends on your amplifier (you don't want to hook something up that's outside the range it can handle), and how you want to configure them. With a single speaker cabinet, it's not a huge deal, but if you want to have the amp drive multiple cabinets, it can become a problem.

Yeah, the more I thought about it I kind of figured that this was about configuring two or more cabs with a single head. With this in mind, I guess my only other question is if something like a 600W head with a 4x10@4 ohms@600W is all I should ever need given my previous post on what I will use it for because that will max out the head's power and not let me add anything else on.

Thanks for all the input,

LEL (Jason)

[66Atlas]

I use an old (American) Ampeg SVTIII pro head that I'm really happy with. Compact and with the built in EQ gives a lot of flexibility. My only complaint would be the cooling fan is kind of loud

For cabinets I'm all over the map and will base it on the size the venue etc. I have 2 cabinets that each have an 18" & 2 10"s as well as a GK 115RBH with a 15" and an HF horn. The larger cabinets are just for bigger shows so for most simple gigs I just drag out the GK, with the horn I get a nice full range sound and the size and weight is really manageable. It also has the nice feature of being able to be used as a floor monitor based on the cabinet shape. They make a 410 version as well I think.

[Fretjob]

CJ, or anyone else, and apologies for a slight thread derail. I do actually have a question regarding speaker power ratings and amp matching.

I’m looking at some gear changes myself and trying to make some old Hartke gear I have work with some potential new Hartke gear purchases.

I like the Hartke 5210 – It’s a 2x10 combo, 8 Ohm Cab, amp output is 500w at 4 Ohms, 350 Watts at 8 Ohms (2 x 10-inch, 16 Ohm, 250 watt Hydrive hybrid conebass transducers)

It can be used with an extension cab. I was thinking of my Hartke 1x15 which is rated at 200W, 8 Ohms.

Hope you can see my problem. How “safe” to use the 200w rated 15” speaker in parallel with the 500w rated 2x10, with an amp capable of 500W at 4 Ohm’s? Am I theoretically drawing approx 250w through each cabinet? If so, I’m not so concerned, i'd never be running them that hard.

[teeder]

It sounded like the OP wanted to keep it simple and only get one cab, which Is why I suggested a 4 ohm 4X10.

Personally, I like to run 8ohm cabs and have just got an Ampeg SVT IV Pro so I can run a 2X10 and 1X15 @ 300 watts for 8 ohms per cab.

[heinpete]

The discussion here about power (Watt) and impedance (Ohm) is interesting !
As I talk about the loudness of my sound system (and not about an electric oven to heat my pan for fried eggs ), however for me the most interesting thing is the efficient SPL in dB!!! There is also a nice non-linear function between Watt and dB!

[teeder]

That's why I loaded my cabs with NOS EV's. It takes a lot less power now to get the same volume with better clarity.

[Low End Lover]

Are you 99% sure that you only want one cabinet and you will have no plans to add a second cabinet in the future?

Sorry, have been too busy working to post... I obviously need to get my priorities straight! Anyway, this is a good point. Since Genz Benz makes a ShuttleMAX 12.0 head and it is only $150 more for twice as much power, which will allow me to add a second cab someday, I may just go that route. The fact that I would have 1200W available seems totally absurd to me, but it will allow me the versitility to add that second cab if the need or desire arises. (Most likely the latter!)

Back to work,

LEL (Jason)