| Home recording and general music post from the archived Yabb Recording Website Message Board. Some of the info here may be outdated but many of the audio recording and home studio tips are still good. Note: The only tags I made and attempt to convert are italics, bold, center and underline. So if you see some gibberish surrounded by brackets, just ignore it.
Recording Website Archived Yabb board Post
Febuary 2001 Yabb Message Board Archive
Subject: RMS handling vs Program handleing
by oesmghroth | 03/13/01 at 10:56:59
[color=Red][/color]
:-/
I have a cabinet that takes 300 RMS and 600 Program.
I want to get a power amp that does not underpower or overpower it. What rating should I use ie(RMS or Program) to get the correct wattage to run the cab at its full potential???
the cab is a 2x10/w horn and is rated at 8 ohms
Subject: Re: RMS handling vs Program handleing
by Frodo | 03/14/01 at 22:26:05
Normal rule of thumb - use twice the rated rms power. The worst is to underpower the cab. You really can't overpower a cab, unless it's a serious cheapie. Or if you get really stupid about it, like hooking up a 2000 watt amp to a 300 watt cab. Underpowering can damage speakers quicker. The amp tries to work too hard to produce the volume you want and sends spikes to the cone. In your case I'd say a 500 watt amp should work. A 300 would probably be okay just be carefull at higher volume levels.
Subject: Re: RMS handling vs Program handleing
by its me again!!!!!!!!!!!! | 03/15/01 at 09:39:28
so if i got like a mackie 1400i it would be ok
or a crown ce 1000
any thing that is more than 300 a side would work right:-/???
what would make a good power amp for a base cab
i gots the preamp now i need the power to run my cabs( one cab being 300 rms 600 prog )
the other involved in a vintage restoration project but around the same rating or higher
Subject: Re: RMS handling vs Program handleing
by Puke | 03/15/01 at 19:11:04
Dude,
It is good practice to WAY overpower stuff.
Hell, some tour companies (at least when I was younger and knew more stuff)..used to run one BRIDGED DC-300A into each 2441 (about a 60 watt tweeter or something like that.).
They would also bridge a DC300A (usually around 350 watts rms into 16 ohms or around 500 into 8 ohms)for every DRIVER on the set..at that time driveers (speakers) usually rated at about 200 watts rms each (honest watts).
A pair of yamaha NS-10m's usually got powered by one
2200 yamaaha amp (that's two 30 watt speakers being
]driven by practically 10 times that much).
A pair of the main room monitors like urei 813s would usually be powered by a BGW 750C....close to 300 watts a side at 8 ohms (more at 4) and one of a few that actually sounded as big as they were rated.
Let me say one more thing. I've heard a lot of these
"newer" big amps rated at more that 500 watts.
And so far I haven't heard all of them, but I've still not heard one even rated at twice what a 750 C
was rated and not sound smaller. So, generally, don't believe the spec. It may put out 1500 watts,
but cheezy ones at that. My estimate is that a true 1500 watt amp would need to run 220 volts only or two 120 volt lines on separate breakers, and also weigh about 200 pounds.
SO BE CAREFUL WHEN LOOKING AT ALL THE NUMBERS, EVEN REPUTABLE AMP COMPANIES ARE PLAYING WITH THE NUMBERS ON SOME OF THEIR MID-GRADE STUFF--INCLUDING CROWN, YAMAHA, BGW, ETC. TETC., However, to date I have never seen McIntosh play with any numbers...what they say you get is exactly what you get.
Subject: Re: RMS handling vs Program handleing
by Gary | 03/16/01 at 11:24:11
which ever power level you go with I would be looking at the slew rate and the dampening
of the amp first.
You want these numbers to be high. say atleast 4o to 45 for the slew rate.
Especialy for bass. Il take a 200 watt amp with high slew rate over a 3 or 400 watt amp with
slew rates in the 20s anyday.
Subject: Re: RMS handling vs Program handleing
by oesmghroth | 03/19/01 at 11:58:02
hehehe
thanks for the advice
i just want an amp that will do the job
the last amp i was using was one of tose ADA bipolar amps on a 2x15 cab and it sounded soo bad whenever i turned it up
i want be able to turn it up and not distort or underpower the speakers
so generaly speaking i can use anthing above 300 watts with a slew of 40 or greater
what about damping factors???????;D
Subject: Re: RMS handling vs Program handleing
by midimachine | 03/19/01 at 19:33:01
The advice you're getting is good. It is always desirable to have an amp that can generate mor eoutput power than the speaker is "rated" to handle. The reason is this:
Most speaker damage happens from a distorted signal being fed to it from the amp. In other words when the amp gets turned up to the point where it's output is distorted, the signal will cause the speaker cone to deform...which invariably causes bad things to happen!
I once worked for a company called Long & McQuade which was in turn owned by Yorkville Sound. At a demo of new NFM's, I saw a guy hook up an AP3000 (1250 watts per side at 2 ohms) to a set of YSM-1 near field monitors (75 watts RMS at 8 ohms). That works out to 312.5 watts a side at 8 ohms! The amp was at about 3/4 and it was LOUD!!!! and clean. The reason was that the power wasn't distorting which meant that the cone was moving cleanly.
Anyway...the lesson is: Always have more power in the amp than the speakers are rated for.
Subject: Re: RMS handling vs Program handleing
by oesmghroth | 03/21/01 at 09:36:43
;D;D;D;D
GREAT!!!!!
this forum whoops......!
Subject: Re: RMS handling vs Program handleing
by oesmghroth | 03/21/01 at 22:22:47
ok got a new one for ya
i was just told that the faster the better for slew rates so a slew of 20 would be faster than 40
so why would i want a slow slew rate for bass??????????????????????????:D:D