Pushing to the max.

[bellis1]

My current rig (for one band) is an SWR 750x with an SWR 8x10. The band that I play this rig with, doesn't ever get mic'd up, because production is usually cheap (usually just 2 mains and our amps). I find myself clipping the SWR 750x, which of course is 750 watts, because sometimes these shows are big, and without a sub to back you up, its hard for my rig to be heard.

So I'm looking to get a SWR MM preamp, and POSSIBLY a Carvin DCM1000L poweramp. This poweramp can run 1000 watts being bridged at 4 ohms. However, I think i'll be using just about that amount of wattage, so should I get something more powerful? So I can have some head room? The problem is my budget is about$400 for a poweramp. And i'm looking for something UNDER 15 pounds. This carvin fits the description.


Please, no criticism. Just advice. If you're going to write "turn your amps down, find a different sound guy, quit", or anything like that, please just don't bother.

[JimmyM]

if you want more volume, you need to add way more than 250w, and you will probably want to plan for a second cab since you'll need 10x the wattage to get twice the volume. honestly, though, i think it's the 750 scooping out the mids more than the lack of powerage. try boosting your mids a little. with that amp, i'd try either 800, 500, or 200 as a center frequency. i used to have an sm-500 and i'd always have to boost 800 to hear it. i see no reason why that rig isn't ripping your head off other than you scooping out the mids.

post your bass and usual settings and we can probably give you some more ideas to get more out of it. and always remember that what works by yourself doesn't always work with the band, so be flexible. but if it turns out you're already getting as much as you can out of it, then i'd recommend adding a second 810 before you bump up the wattage. of course, that will mean you couldn't use the 750x anymore, but there are tons of power amps out there that will work for you.

[Son of Bovril]

+1 Jimmy, it's most likely something in your tone settings causing you to have to push the head so hard, or maybe it's just the voicing of the amp that isn't giving you what you want...

where is your aural enhancer set? and I also agree that boosting at 200, 500 or 800 (depending on your taste and the band mix) should help your sound cut through better

the only other thing I could recommend would be a compressor firstly for a bit of protection if you are pushing the amp so hard and it also may allow you to squeeze a tiny bit more volume from the rig

[Sartori]

SWR's are (in)famously mid scooped. Try boosting up those mids.

Also, IIRC, isn't the aural enhancer basically a mid-scoop? Probably want to not use it, if so.

[okcrum]

Check tone settings, as others have mentioned, and maybe spend your money on some more 10s instead of more watts.

3 db SIL doesn't require 10 dB more amp power unless something in the amp chain is running out of gas - like the speakers. I'm still trying to get an answer from someone where that assumption came from.

7500 watts wouldn't be twice as loud as 750; it would put the cab into low earth orbit.

[Son of Bovril]

from what I've read, the commonly accepted ratio is that it requires 10x more watts to double the volume of the amp through the same cab, assuming everything else stays the same and the cab can handle it...

Hence if you need volume it is obviously better to add speakers instead, although it does obviously help to be running the speakers at their optimum wattage as well.

As for headroom, tone and perceived volume that is a completely different thing...

The aural enhancer (on my older workingman) boosts mids up until about 12 o'clock and does the classic mid scoop & high+low boost thereafter, although I heard they changed the design on more recent models, or was that just the sub frequency boost?

[KJung]

Originally Posted by bellis1

My current rig (for one band) is an SWR 750x with an SWR 8x10. The band that I play this rig with, doesn't ever get mic'd up, because production is usually cheap (usually just 2 mains and our amps). I find myself clipping the SWR 750x, which of course is 750 watts, because sometimes these shows are big, and without a sub to back you up, its hard for my rig to be heard.

So I'm looking to get a SWR MM preamp, and POSSIBLY a Carvin DCM1000L poweramp. This poweramp can run 1000 watts being bridged at 4 ohms. However, I think i'll be using just about that amount of wattage, so should I get something more powerful? So I can have some head room? The problem is my budget is about$400 for a poweramp. And i'm looking for something UNDER 15 pounds. This carvin fits the description.


Please, no criticism. Just advice. If you're going to write "turn your amps down, find a different sound guy, quit", or anything like that, please just don't bother.

As one who has spent quite a bit of time with the 750x, both as provided backline on quite a few gigs, and also messing with one that was sitting in a local retail bass store for many months with various different cabs, that head performs more like a 300 watt head. There is something VERY strange about that particular head, and into 4ohms, we all found that an Eden WT550, and Markbass LMII and a variety of other '500 watt heads' EASILY outperformed that particular head in both usable low end and absolute volume.

So, I would suggest trying a couple of different heads with your cab on the gig. You might not need as many watts as you think, but just a more honestly rated head (or, to be fair, maybe a head just voiced to take more advantage of the published wattage spec). If you like the SWR 'x' type vibe (which to my ear is a bit more grindy rock voiced than the very pure 500 or 900 series amps), I would HIGHLY recommend at least trying a Shuttle 9 with your cab. While that head doesn't really sound like a '900 watt' head, it is WAY louder and punchier than the 750x, and weighs nothing.

Just an idea.

[AlexanderB]

Interesting to hear about the disparate characters of these (not too different) SWR products. Especially for a company talking a lot of "the SWR sound" and marketing the 750X as capable of "crushing volume". I guess "YMMV" in this case...

/Alexander

[Matthijs]

[quote=okcrum;9763545]
3 db SIL doesn't require 10 dB more amp power unless something in the amp chain is running out of gas - like the speakers. I'm still trying to get an answer from someone where that assumption came from.
QUOTE]

Do you mean 3db SPL? Otherwise I don't really understand what assumption you want an answer for. The rule people are referring to is double the volume is ten times the wattage, wich equates to 10db spl requires 10 times the wattage.

[KJung]

Originally Posted by AlexanderB

Interesting to hear about the disparate characters of these (not too different) SWR products. Especially for a company talking a lot of "the SWR sound" and marketing the 750X as capable of "crushing volume". I guess "YMMV" in this case...

/Alexander

I think the issue here (in this thread) is everyone is assuming that the published wattage specs can be compared across amps. This is never the case. Wattage specs are given across amp lines at different THD and frequency ranges, and preamps all have different voicings, with hi pass filters set very differently, big low end bumps or mid scoops baked into some, etc., etc., etc.

Of course, then there is out and out inaccuracy in some marketing specs.

So, all the talk of 3db this and 'x more watts' that, while meaningful and correct in an absolute sense in the laboratory, doesn't really apply when talking about different manufacturers' products (and even different lines within the same manufacturer).

Then there is cab SPL, but that should not be a problem with the particular 'Megaliath' cab the OP is using... relatively mid present and hence relatively high SPL (at least the way SPL is measured with most bass cabs).

IMO and a lot of IME with that particular head. That head wins the 'KJUNG award' for least db output per pound.

[Matthijs]

Originally Posted by KJung

db output per pound

Now there's a interesting way to measure your rig. Can't we make this in to a talkbass test standard?

[plangentmusic]

You play big halls and you don't have a Direct Out?

750 watts is MORE than enough power in just about any venue I can think of, though I suspect SWR's stats. They never seem as powerful as the numbers would suggest.

[AlexanderB]

Yeah, Ken, I am with you regarding the voicing etc. (By the way, I left the dB out of discussion, it was Matthijs brought that up.)
My concern was more that SWR produce two rather similar amps (SM 900 and 750 X), big, old school with parametric EQ, tube input stage etc but with what seems to be very different voicing. And still I often see marketing refering to "that SWR sound".

By the way, a rack mount Studio 220 will give the 750 X a run for the money. Not as big as the 750, but really quiet, too. It is the weakest, softest bass amp I have seen (and almost heard...)

/Alexander

[okcrum]

[quote=Matthijs;9763718]

Originally Posted by okcrum

3 db SIL doesn't require 10 dB more amp power unless something in the amp chain is running out of gas - like the speakers. I'm still trying to get an answer from someone where that assumption came from.
QUOTE]

Do you mean 3db SPL? Otherwise I don't really understand what assumption you want an answer for. The rule people are referring to is double the volume is ten times the wattage, wich equates to 10db spl requires 10 times the wattage.

SPL (sound pressure level) is an acoustic field measurement, and correlates to voltage. 6 dB SPL = 6 dB voltage = twice as loud, all other things being the same.

SIL (sound intensity level) is a power flux (acoustic power through an area) measurement. 3 dB SIL = 3 dB power = twice as loud, all other things being the same. It's harder to measure than SPL, as you might imagine.

Ten times the wattage produces a 20 dB change in SPL, a 10 dB change in SIL, and it's TEN times as loud, all other things being equal.

What I was asking is, where did this old wives tale about ten times the power for twice the volume come from? Look at the numbers in the OP's case; it's ridiculous to recommend 7500 watts to double his volume. Doesn't that give anyone a hint that this 10x "rule" is bogus?

[Ronny49]

I am an SWR user and my experience with the X series is also not a good one. The amps sound sweet, but are NOT loud enough. Very under-rated IMO. That's why I chose to move to the SM series. These amps are much better and rated more accurately, especially the REAL SWR's, prior to 2003 when Fender took them over.

If I were you, I would look into getting an SM 900 and another 410 cab. This will blow your mind and the fans minds!