There are certain toerag audio vendors whom state the peak power output of
their audio equipment in pmpo values. I'm aware that in order to obtain an
accurate conversion to rms one would require voltages current etc. Is there
an arbitrary equasion so one could get a rough comparison?

Thanks.

On Fri, 19 Mar 2004 10:49:37 +0000, Putomadre wrote:

There are certain toerag audio vendors whom state the peak power output of
their audio equipment in pmpo values. I'm aware that in order to obtain an
accurate conversion to rms one would require voltages current etc. Is
there an arbitrary equasion so one could get a rough comparison?


Not really. "pmpo" seems to mean anything that the vendors want it to -
like "the most that we can get out of this junk as a 20ms wide pulse with
one channel driven in the hope that our competitors can't think of a
higher number for a 5W rms amp". :-)

Strictly speaking, pmpo means what it says - peak music power output - but
doesn't specify what sort of music it is being measured on, how wide the
peak sample is, how many channels are being driven, whether they are using
the internal or an external power supply etc. All these have been
warped and used in the past to be able to quote nice high numbers that
look impressive in catalogues. I tend toward the theory that any equipment
that only quotes a pmpo rating is probably a 2.5W RMS per channel
amplifier at best - and I don't think I'm wrong very often from what I've
heard!

I thought so Format, I wonder if the Trades descriptions act comes into play
here?


"Form@C" wrote in message
news
On Fri, 19 Mar 2004 10:49:37 +0000, Putomadre wrote:

There are certain toerag audio vendors whom state the peak power output
of
their audio equipment in pmpo values. I'm aware that in order to obtain
an
accurate conversion to rms one would require voltages current etc. Is
there an arbitrary equasion so one could get a rough comparison?


Not really. "pmpo" seems to mean anything that the vendors want it to -
like "the most that we can get out of this junk as a 20ms wide pulse with
one channel driven in the hope that our competitors can't think of a
higher number for a 5W rms amp". :-)

Strictly speaking, pmpo means what it says - peak music power output - but
doesn't specify what sort of music it is being measured on, how wide the
peak sample is, how many channels are being driven, whether they are using
the internal or an external power supply etc. All these have been
warped and used in the past to be able to quote nice high numbers that
look impressive in catalogues. I tend toward the theory that any equipment
that only quotes a pmpo rating is probably a 2.5W RMS per channel
amplifier at best - and I don't think I'm wrong very often from what I've
heard!

On Fri, 19 Mar 2004 13:10:39 +0000, Putomadre wrote:

I thought so Format, I wonder if the Trades descriptions act comes into
play here?


g Probably not. Providing that they have a documented procedure that
comes up with the pmpo value used in the advertising I doubt if there is
anything actually wrong! After all, there isn't any real standard for amp
power anyway. Even if you see Watts rms quoted, does it always say "with
both channels driven" and "measured using a 1kHz sine wave"? No. I thought
not - and pmpo is arguably more accurate from a listener's point of view
anyway. Most people don't get a buzz out of listening to 1kHz sine waves -
they tend to prefer music!

It all boils down to this - listen to the gear and, if you like what you
hear, buy it (or finish the construction details at that point!). Forget
the numbers game. It isn't really relevant to most listeners anyway. If
you are aiming for true "hi-fi" and are comparing "proper"
specifications (usually measured rather than "designed to be" values) then
things are a bit different, but for the majority of us the numbers are
just something to fill the specs up and don't really give us any idea what
the sound is going to be like.

Putomadre wrote in message
...
There are certain toerag audio vendors whom state the peak power output of
their audio equipment in pmpo values. I'm aware that in order to obtain an
accurate conversion to rms one would require voltages current etc. Is
there
an arbitrary equasion so one could get a rough comparison?

Thanks.

RMS is 0.707 of a peak-to-peak AC Voltage.

PMPO is something invented by the trade to make the output of a grotty amp
look better. I'd avoid any traders quoting output power as PMPO.

Nemo

nemo wrote:
Putomadre wrote in message
...
There are certain toerag audio vendors whom state the peak power
output of their audio equipment in pmpo values. I'm aware that in
order to obtain an accurate conversion to rms one would require
voltages current etc. Is there an arbitrary equasion so one could
get a rough comparison?

Thanks.

RMS is 0.707 of a peak-to-peak AC Voltage.

PMPO is something invented by the trade to make the output of a
grotty amp look better. I'd avoid any traders quoting output power as
PMPO.

Computer speakers are even more empressive.
I'm amazed to se 125W amplified speakers driven by a 5W wall wart...

Leif