Underpowering my Subs
in [Live Sound]
|
From: Michael Dobony on 30 Jan 2010 11:38 On Thu, 28 Jan 2010 16:43:01 -0600, JWald wrote: >>snip as already covered well<< >will I seriously > underpower my subs and put my amps in jeopardy? Thanks. the amp does not know the power rating of the subs. To the amp it is a 4 ohm load, no matter what the power rating. 1100 watts into a 700 watt speaker is not underpowered. If anything it is your subs you need to be worried about. It is common to run an "oversized" amp and keep it down rather than to attempt to perfectly match the amp to the speaker. It places less load on the amp to run it at lower levels.
From: JWald on 30 Jan 2010 13:40 "liquidator" <mikeh(a)mad.scientist.com> wrote in message news:hk05p3$ico$1(a)news.eternal-september.org... > > "JWald" <wldj4(a)grics.net> wrote in message > news:hjvmun012mh(a)enews2.newsguy.com... >> >> I think that we are agreeing. > > No we aren't > > > I stated that to make one sub work correctly I >> need a 4 conductor cable between the PLX output and 1 sub. > > No you don't you can run a 2 condcter from the PLX and make the > connections at the sub end of the cable, just connect the pins like I told > you. > > > > My trouble comes >> from the fact that I only have 1 PLX, and therefore cannot run a second >> sub. > > 100% wrong, you just need to learn. > >> I decided to run both subs with a couple of RMX 2450's at 750w @4ohms. >> That would be 1 amp per sub. > > No reason to do that but if it floats tour boat... > > > Am I completely misunderstanding this? > > Yup. > > Just run a standard two conductor wire from each channel of the PLX and > connect the pins on a 4 pin at the sub end like I told you > positive first woof to positive second woof > > Neg first woof to neg second woof. > > Electronics 101 > Sorry. I couldn't get past the 4 conductor input at the sub. I never thought of jumping pins on the cable to feed the sub. Thanks. -- J Wald "You can lead a horticulture, but you can't make her think.... "
From: liquidator on 30 Jan 2010 17:06 "JWald" <wldj4(a)grics.net> wrote in message news:hk1uf20302p(a)enews5.newsguy.com... > > > "liquidator" <mikeh(a)mad.scientist.com> wrote in message > news:hk05p3$ico$1(a)news.eternal-september.org... >> >> "JWald" <wldj4(a)grics.net> wrote in message >> news:hjvmun012mh(a)enews2.newsguy.com... >>> >>> I think that we are agreeing. >> >> No we aren't >> >> >> I stated that to make one sub work correctly I >>> need a 4 conductor cable between the PLX output and 1 sub. >> >> No you don't you can run a 2 condcter from the PLX and make the >> connections at the sub end of the cable, just connect the pins like I >> told you. >> >> >> >> My trouble comes >>> from the fact that I only have 1 PLX, and therefore cannot run a second >>> sub. >> >> 100% wrong, you just need to learn. >> >>> I decided to run both subs with a couple of RMX 2450's at 750w @4ohms. >>> That would be 1 amp per sub. >> >> No reason to do that but if it floats tour boat... >> >> >> Am I completely misunderstanding this? >> >> Yup. >> >> Just run a standard two conductor wire from each channel of the PLX and >> connect the pins on a 4 pin at the sub end like I told you >> positive first woof to positive second woof >> >> Neg first woof to neg second woof. >> >> Electronics 101 >> > Sorry. I couldn't get past the 4 conductor input at the sub. I never > thought of jumping pins on the cable to feed the sub. Thanks. > -- > J Wald > > "You can lead a horticulture, but you can't make her think.... " > > It's funny isn't it, the simple things elude us sometimes...;-) We are looking for a complicated answer not a simple one...
From: Rupert on 31 Jan 2010 03:19 On Jan 30, 8:38 am, Michael Dobony <sur...(a)stopassaultnow.net> wrote: > On Thu, 28 Jan 2010 16:43:01 -0600, JWald wrote: > >>snip as already covered well<< > >will I seriously > > underpower my subs and put my amps in jeopardy? Thanks. > > the amp does not know the power rating of the subs. To the amp it is a 4 > ohm load, no matter what the power rating. 1100 watts into a 700 watt > speaker is not underpowered. ---- > If anything it is your subs you need to be > worried about. It is common to run an "oversized" amp and keep it down > rather than to attempt to perfectly match the amp to the speaker. It is common to run an amp with a continuous power rating around 2x the rms rating of a speaker. This is not considered "oversized" and "keeping it down" is not an issue. It's considered the program power and is the usual recommended amp power by most speaker manufacturers. The reasoning is that "music signals" running through a speaker have a much higher crest factor than test signals used to determine the rms or continuous power rating. This allows you to get a bit more output and headroom compared to running the speaker at it's rms power rating. With more modern setups using DSP with 2-stage limiting, it's possible to safely run amps with up to 4x the rms or continuous rating of a loudspeaker and not blow things up. This allows up to 6dB more peak output compared to an amp matched to only the rms rating of the speaker. Using 4x the rms speaker rating is NOT recommended with more standard setups with peak/clip only limiting as the probability of cooking drivers is very high. > It places less load on the amp to run it at lower levels. No, the load is the same regardless of the level. It will place less thermal stress on the amp to run it at lower levels. But keep in mind turning an amp down on the front panel will not reduce maximum output capability of the amp. It merely changes the amount of input required to get it there. And any amp that's worth is salt will not be overly stressed running up to clip levels even with low impedance loads. If that's a problem for the amp, it has no place in pro audio. Rupert
From: George's Pro Sound Co. on 31 Jan 2010 20:19
It is common to run an amp with a continuous power rating around 2x the rms rating of a speaker. I agree it is common, and often done, just as leaving the input attentuators to minimum attentuation is. I will also agree many many well meaning people will qoute this as gospel, Myself, I won't do it, IMO it is foolish to attempt to go around a corner at twice the posted speed limit and just as foolish to run 2x the amp into a speaker but this has been debated ad nausum both here and in other foru,ms and the trade magazines do so at your own risk, you will get away with it and there is no "one number" that is universially considered proper Debate it as you will I am out of this thread George |