Over the decades of playing I realize that you don’t need that much. Your signal should be going to the FOH and spread around the monitors. Loud stage volume messes up everything anyway. 500w is enough for any situation….
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How do you determine how much power is enough?
- Thread starter nightchef
- Start date
Totally my experience too. Running 215 cabs (or 2 singles) I never once boosted the low freq eq on my amps and always had all the low end required by my loud but rational bands.
Someone on here once posted the right amount of power was when you could feel it in your balls but not so much that it was painful.
I start with the cab(s), then if they're rated at 600W each then I'll pick a quality amp that can reliably handle 400W or so to each. If I need more, add another cab or two. I won't need more. In reality, combo for small to medium situations. Larger medium to large gigs, separates. I don't really worry about the numbers. The rule of thumb used to be you need a 15 and 300W. Cabs are way better now and the amps in them are lighter. I think that if I were starting from scratch I'd go with a good combo with a 12" and an extension cab if I need it.
Power or wattage isn’t the only factor. One 500 head may or may not be louder than another. Then there are cabs and how efficient they are. Hmmm. What is your typical venue? Can you drive to if or do you arrive backstage in a helicopter? Do you need massive stage volume or could a nice combo going to FOH work? So with all that are you ready to order or do you need more time? BTW the grilled Sea Bass is spectacular tonight!
I've had good results by generally going overboard and dialling the volume down to an appropriate level.
It's not like there's a prize for bringing the right amount.
It's not like there's a prize for bringing the right amount.
Somehow in the 1990s, a GK 400RB was just fine for a working general business band. Would I enjoy it now? No, I'd miss the headroom. Could I make it work? Obviously. If it worked then it would work now. We're spoiled beyond belief.
Besides, watt ratings means almost nothing. I'm regularly gigging with a Mesa Boogie Prodigy now and it's rating is 250 watts. I believe the 400RB was 180 watts into 8 ohms and the Prodigy blows the GK out of the water.
Nothing is the same now as it was in 1994.
The PA speakers and bass cabs rarely had ratings above 200 watts RMS.
My current guitarist doesn't even use an amp. The entire premise of this thread is invalid.
Besides, watt ratings means almost nothing. I'm regularly gigging with a Mesa Boogie Prodigy now and it's rating is 250 watts. I believe the 400RB was 180 watts into 8 ohms and the Prodigy blows the GK out of the water.
Nothing is the same now as it was in 1994.
The PA speakers and bass cabs rarely had ratings above 200 watts RMS.
My current guitarist doesn't even use an amp. The entire premise of this thread is invalid.
Many don't have any FOH, some not consistently, or might not get their bass put into FOH...
just sayin'
No easy way. My experience, though, is that a loud band will be loud at rehearsals more than live (because loud bands don't play in pubs and can expect the venue to have decent equipment), so any bottlenecks will emerge there.
In my opinion, a 500W head, even one of the clean ones and with an aggressive limiter to ensure that you stay clean, and a suitable cabinet will take you anywhere. These days, unless you are expected to be your own PA, you can use basically anything. Especially if you use in-ear monitors. Actually, you might as well not even have an amp.
And no. I don't believe in high-powered amps. No practical bass cabinet is going to reproduce more than so-many watts, and power compression will sooner or later come into play. A single woofer (for bass guitar applications, anyway) shouldn't be expected to output more than, say, 300-400W (not much difference). That may be an optimistic figure. Those high-power woofers you see. Have a look at their frequency response. They are going to be dedicated subwoofers most of the time, and they won't cut it for bass, no mids. There may be some exceptions, but the usual bass cabinet employs relatively cheap woofers.
- Feb 12, 2006
- 61,062
- 5
- 221,099
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
And most older cabinets didn't have such great LF extension anyway...
I switched to low powered tube amps a little over 10 years ago and now have 25, 50 and 100 watt options to pair with 1x115, 2x115 or 1x410 cabs. Steady gigging, first 3 of the 10 years with tubes in a trio playing rock covers, now for the last 7 years in an original blues band (barrelhouse, nothing meek or loungy about it). In this blues band we play everything from festivals to theaters to large clubs to small dives, and I have never been underpowered in any situation. I carry a 250 watt micro head in my gig bag just in case, but it's never seen the light of day. I went low powered tube specifically for the sound of power tubes as they approach breakup. There's nothing more boring to me than a "clean" bass sound, but that is strictly my taste and no reflection on anyone who wants clean. With the capability of modern FOH systems it's beyond me why anyone would need 800 watts, but again that's just me.
Many don't have any FOH, some not consistently, or might not get their bass put into FOH...
just sayin'
yeah I remember owning an SVT. It was glorious. Still 500w will get you where you need to go!
If I'm playing situations where I have to consistently turn up past halfway, I know I need to go bigger. I did gig a GKMB112 for years and even did an outside no PA support gig, but ran the volume at about 80% all night, which is not something I'd want to do consistently for 3+ hour gigs.
Certainly not gonna argue with the Was's math(mostly 'cause it's correct), but where some of us would struggle doing it this way is knowing what our target SPL should be. If I think my biggest gig will be an 800 person club, and we have a guitarist with a 50 watt Mesa and a 2x12, and the drummer has decent control of dynamics, and there's no FOH, I don't know how I'd estimate what SPL I'd need out of my bass amp.
I agree with this. 100 watt tube amp into an efficient 4-10 or 2x210 situation can get darn loud.
- Feb 12, 2006
- 61,062
- 5
- 221,099
- Disclosures
- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
Knob position doesn’t necessarily correlate with running the amp hard. Some amps have gain/volume that increases linearly throughout the control’s entire rotation.
You have to start somewhere. Hopefully you have a pretty good idea how well your current rig meets your needs. Experiment with your current rig to assess how close you typically are to running out of headroom. FYI the position of the knobs don't tell you jack!
If your current rig is always significantly louder than you need, do the math and you have a pretty good baseline for the future. If you frequently push the rig right up to the limit, consider how often you do louder gigs and assess if you need a more capable rig. +3dB is barely perceivable. +6dB is clearly noticeable. +9dB or +12dB are large increases in SPL.
Keep in mind max SPL is only part of the answer. You also need a rig that produces a sound and feel that you find pleasing.
Through a given speaker you get approximately +3db every time you double the power.
Let's assume you typically use 120W
+3dB = power x 2 = 240W
+6dB = power x 4 = 480W
+9db = power x 8 = 960W
+12dB = power x 16 = 1,920W
+6dB = power x 4 = 480W
+9db = power x 8 = 960W
+12dB = power x 16 = 1,920W
Hopefully you see that at some point it no longer makes sense to increase the power--How many speakers can handle 960W or more?
Often it's better to increase the number of speakers. If you add a matching cab and the power stays the same, you get +3dB. If you add a matching cab and double the power you get +6dB. If you add a matching cab and quadruple the power you get +9dB.
As an example, 120W into a Ampeg 810E is rated for about 121dB calculated. So maybe the amp is a cranked V4B
With an SVT we assume available clean power goes up to about 300W. The dB difference from 120W to 300W is about 4dB. So your new max SPL is about 125dB calculated.
If you think you need even more headroom you either add a matching cab for +3dB, or you can get an amp that makes twice as much power (600W) for +3dB. Now your at about 128dB calculated
Some people say the Aguilar ToneHammer 700 can be dialed in to sound similar to an SVT. 700W into one 810E = 128.5dB calculated. So the TH700 with an 810E should be capable of about the same volume as an SVT with a pair of 810Es.
Remember we started at 121dB with the V4B and are only up +7.5dB to 128.5dB with the TH700. In order to get +9dB or +12dB, your going to need a 2 ohm capable amp and two 810Es. This is because the 810E is only rated for 800W, so it does not have enough reserve power handling to produce significantly more volume. FYI, the dB difference from 700W to 800W is about 0.6dB.
480W into a pair of 810Es is about 129.8dB calculated (+8.8dB) This is quadrupling the original power (120W) and adding a matching cab.
960W into a pair of 810Es is about 132.8dB calculated (+11.8dB)
Let's max out two 810Es.
[Log(1600) x 10] + 103 = 135dB.
This is adding a matching cab and multiplying the original 120W by 13.333...An example of an amp that could do this is an Ampeg SVT 8-Pro rated for 2500W at 2 ohms. Don't forget the ear plugs...at 135dB
, you should probably consider one of these as well:
ROCK ON 
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