"Portable" party sound system using auto sound equipment.

http://flickr.com/photos/43996336@N00/?saved=1

----------------------------------
Easy's getting harder everyday.

"PanHandler" wrote in news:aAAhg.14255$EX2.1035
@bignews5.bellsouth.net:

"Portable" party sound system using auto sound equipment.

http://flickr.com/photos/43996336@N00/?saved=1

Why do you call it a 1600 watt system? Your power supply can only provide
32 amps at 12 volts, which is less than 400 watts power. Even with a high
efficiency power amp, you are limited to less than 250 watts.

--
Murray Peterson

"Murray Peterson" wrote in message
...
"PanHandler" wrote in news:aAAhg.14255$EX2.1035
@bignews5.bellsouth.net:
"Portable" party sound system using auto sound equipment.
http://flickr.com/photos/43996336@N00/?saved=1
Why do you call it a 1600 watt system? Your power supply can only provide
32 amps at 12 volts, which is less than 400 watts power. Even with a high
efficiency power amp, you are limited to less than 250 watts.

Glad you brought this to my attention. It was a typo - it's a 1400 watt amp
(4X 350). The power supply is rated 35 amps @ 12 volts, and I keep it set at
13.8 volts. Regardless, at near the pain threshold, the amp only draws
approximately 25 amps on bass peaks. The speakers are quite efficient @ 92
db.

"PanHandler" wrote in
:

Glad you brought this to my attention. It was a typo - it's a 1400
watt amp (4X 350). The power supply is rated 35 amps @ 12 volts, and I
keep it set at 13.8 volts

That's not even close to 1400 watts, no matter what the amp manufacturer
tells you. 35 amps * 12 volts = 420 watts input. A perfectly efficient
class B amp can provide 70.7% efficiency, so that leaves you with a
maximium amplifier power of 296 watts. Being less than perfect, don't
expect that amp to be providing more than 200 watts (250 if you are lucky).

--
Murray Peterson
Email:
URL: http://members.shaw.ca/murraypeterson/

Murray Peterson spake thus:

"PanHandler" wrote in
:

Glad you brought this to my attention. It was a typo - it's a 1400
watt amp (4X 350). The power supply is rated 35 amps @ 12 volts, and I
keep it set at 13.8 volts

That's not even close to 1400 watts, no matter what the amp manufacturer
tells you. 35 amps * 12 volts = 420 watts input. A perfectly efficient
class B amp can provide 70.7% efficiency, so that leaves you with a
maximium amplifier power of 296 watts. Being less than perfect, don't
expect that amp to be providing more than 200 watts (250 if you are lucky).

I think there's a semantic or comprehension problem here (and not on the
part of the O.P.). He or she says they have a 1400 watt amp; let's take
their word for that.

Of course, at 35 A @ 12 V, he or she isn't going to get 1400 watts out
of it. But that's another matter.


--
Any system of knowledge that is capable of listing films in order
of use of the word "****" is incapable of writing a good summary
and analysis of the Philippine-American War. And vice-versa.
This is an inviolable rule.

- Matthew White, referring to Wikipedia on his WikiWatch site
(http://users.erols.com/mwhite28/wikiwoo.htm)

David Nebenzahl wrote in
.com:

I think there's a semantic or comprehension problem here (and not on
the part of the O.P.). He or she says they have a 1400 watt amp; let's
take their word for that.

Why? Take a look at this pictu
http://flickr.com/photo_zoom.gne?id=162367000&size=o
If you look closely, you will see that his power supply is a Pyramid PS-
36KX. That unit provides a constant output of 32 amps at 12V.

Of course, at 35 A @ 12 V, he or she isn't going to get 1400 watts out
of it. But that's another matter.

Certainly not one of semantics. 32A * 12V * .707 = 271 watts at perfect
efficiency. A "real world" amp is more liekly to produce something closer
to 200-250 watts output with that power supply.

--
Murray Peterson

Murray Peterson spake thus:

David Nebenzahl wrote in
.com:

I think there's a semantic or comprehension problem here (and not on
the part of the O.P.). He or she says they have a 1400 watt amp; let's
take their word for that.

Why? Take a look at this pictu
http://flickr.com/photo_zoom.gne?id=162367000&size=o
If you look closely, you will see that his power supply is a Pyramid PS-
36KX. That unit provides a constant output of 32 amps at 12V.

Of course, at 35 A @ 12 V, he or she isn't going to get 1400 watts out
of it. But that's another matter.

Certainly not one of semantics. 32A * 12V * .707 = 271 watts at perfect
efficiency. A "real world" amp is more liekly to produce something closer
to 200-250 watts output with that power supply.

That doesn't change the fact that the *amplifier* could be rated at 1400
watts--regardless of whether the power supply can provide that power or
not. See what I mean?


--
Any system of knowledge that is capable of listing films in order
of use of the word "****" is incapable of writing a good summary
and analysis of the Philippine-American War. And vice-versa.
This is an inviolable rule.

- Matthew White, referring to Wikipedia on his WikiWatch site
(http://users.erols.com/mwhite28/wikiwoo.htm)

In article ,
David Nebenzahl wrote:

That doesn't change the fact that the *amplifier* could be rated at 1400
watts--regardless of whether the power supply can provide that power or
not. See what I mean?

Does the manufacturer state that the amp is rated at 1400 watts of
continuous power? or do they just say "1400 watts" and not give the
conditions of the test?

It's possible that the amp might deliver a short pulse at a 1400-watt
rate, even when hooked to the existing power supply... but this would
only go on for as long as the charge in the amp's own filter
capacitors held up.

Describing amplifiers using an unspecified-width (but short) peak
power output level is fairly common for car amps, and even moreso for
computer-speaker systems. Use such figures for what they're worth...
:-(

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Dave Platt spake thus:

In article ,
David Nebenzahl wrote:

That doesn't change the fact that the *amplifier* could be rated at 1400
watts--regardless of whether the power supply can provide that power or
not. See what I mean?

Does the manufacturer state that the amp is rated at 1400 watts of
continuous power? or do they just say "1400 watts" and not give the
conditions of the test?

It's possible that the amp might deliver a short pulse at a 1400-watt
rate, even when hooked to the existing power supply... but this would
only go on for as long as the charge in the amp's own filter
capacitors held up.

Describing amplifiers using an unspecified-width (but short) peak
power output level is fairly common for car amps, and even moreso for
computer-speaker systems. Use such figures for what they're worth...

Notice that nowhere did I endorse the claim that the amplifier actually
can deliver 1400 watts of power: all I'm saying is that it could well
say that on a label somewhere. So it could be a (nominal) 1400 watt amp,
regardless of whether it could ever come close to sending that amount of
power down the wires.

I think we've all gotten the point by now that no matter *what* the amp
is rated at, you ain't gonna get more than the power supply can give.


--
Any system of knowledge that is capable of listing films in order
of use of the word "****" is incapable of writing a good summary
and analysis of the Philippine-American War. And vice-versa.
This is an inviolable rule.

- Matthew White, referring to Wikipedia on his WikiWatch site
(http://users.erols.com/mwhite28/wikiwoo.htm)

"Dave Platt" wrote in message
...
In article ,
David Nebenzahl wrote:

Does the manufacturer state that the amp is rated at 1400 watts of
continuous power? or do they just say "1400 watts" and not give the
conditions of the test?

It's possible that the amp might deliver a short pulse at a 1400-watt
rate, even when hooked to the existing power supply... but this would
only go on for as long as the charge in the amp's own filter
capacitors held up.

Describing amplifiers using an unspecified-width (but short) peak
power output level is fairly common for car amps, and even moreso for
computer-speaker systems. Use such figures for what they're worth...

Specs: Logic PLX4800
MAX Power @ 2 Ohm 350W x 4 CH
RMS Power @ 4 Ohm 175W x 4 CH
S/N Ratio 102 db
THD (4 Ohm) 0.01 %
Freq Response + 1.0 db 10 Hz - 35 KHz *

I mostly understand the comments throughout this thread (except the '+
1.0 db') here *. I know it's just a cute way to emblazon the pretty blue &
chrome unit with big numbers. I DID read the specs and reviews before buying
it, and (bottom line), I'm satisfied with the price/performance ratio. This
project wasn't intended for critical listening in acoustically correct
rooms. It's for noisy in & outdoor parties. Hell, the two computer cooling
fans sound like wind turbines.
I've learned a lot hanging out in the group, and basically this is just a
fun thing to do along with my computer and photography hobbies. I appreciate
everybody's comments and putting up with my antics.
Now if I could just figure out where to mount the beer tap! Look here
http://flickr.com/photos/43996336@N00/page5/ at the bottom for the computer
work station.

Joe Arnold

"PanHandler" wrote in message
...
Now if I could just figure out where to mount the beer tap! Look here
http://flickr.com/photos/43996336@N00/page5/ at the bottom for the
computer work station.

Page 6 now.
http://flickr.com/photos/43996336@N00/page6/

PanHandler wrote:

The speakers are quite efficient @ 92 db.

Actually that's pretty miserable efficiency. Proper pro-audio SR gear has tyical
efficiencies in the 98-103 dB/W@1m region.

Graham

PanHandler wrote:

Regardless, at near the pain threshold, the amp only draws
approximately 25 amps on bass peaks. The speakers are quite efficient @ 92
db.

You're not going to get anywhere near the pain threshold with that lot unless
it's constantly clipping of course in which case it *would* be painful to listen
to.

Graham

Murray Peterson wrote:

David Nebenzahl wrote in
.com:

I think there's a semantic or comprehension problem here (and not on
the part of the O.P.). He or she says they have a 1400 watt amp; let's
take their word for that.

Why? Take a look at this pictu
http://flickr.com/photo_zoom.gne?id=162367000&size=o
If you look closely, you will see that his power supply is a Pyramid PS-
36KX. That unit provides a constant output of 32 amps at 12V.

But where's the amplifier ?

Graham

Dave Platt wrote:

Does the manufacturer state that the amp is rated at 1400 watts of
continuous power? or do they just say "1400 watts" and not give the
conditions of the test?

In car audio is typically rated with 'peak rating' and 10% distortion. The power
ratings are no way comparable with hi-fi gear for example. To make a more normal
comparison you need to divide by 2-3 minimum typically.

Graham

"Pooh Bear" wrote in message
...


PanHandler wrote:

Regardless, at near the pain threshold, the amp only draws
approximately 25 amps on bass peaks. The speakers are quite efficient @
92
db.

You're not going to get anywhere near the pain threshold with that lot
unless
it's constantly clipping of course in which case it *would* be painful to
listen
to.

By 'near', I meant it was just too loud for comfortable listening the room
it was set up in. It doesn't do badly at all. My next experiment will be to
parallel a couple good batteries and see what it's really made of.

PanHandler wrote:

Specs: Logic PLX4800
MAX Power @ 2 Ohm 350W x 4 CH
RMS Power @ 4 Ohm 175W x 4 CH
S/N Ratio 102 db
THD (4 Ohm) 0.01 %
Freq Response + 1.0 db 10 Hz - 35 KHz *

So if the 'rms' power is 175W - where does 350 come from ? I'll bet it's the
typical 'peak instantaneous' power so beloved of ICE makers.

So equivalent to a 'normal' 4 x 175W amp i.e. 700W.

But furthermore It looks to me like it's rated into 2 ohm loads. Unless those
cabinets are 2 ohms and I bet they're not - you're likely looking at ~ 100W into
4 ohms / channel or maybe 60W into 8 ohms.

Suppose the speakers are indeed 4ohms. That's ~ 400W rms continuos power but
actually the dynamics of music mean that the averaged power is likely to be more
in the region of 200W.

Add in the amplifier's efficiency and the 25A peaks now start to make sense.

In short it isn't a 1600W or even a 1400 W system but more like 400W.

Graham

In article , Pooh Bear wrote:


PanHandler wrote:

The speakers are quite efficient @ 92 db.

Actually that's pretty miserable efficiency. Proper pro-audio SR gear has
tyical
efficiencies in the 98-103 dB/W@1m region.

Lets say for home audio its efficient. Cerwin Vega home speakers may play louder.
Car audio woofers are NOT efficient, designed for small boxes and a lot
of power.

greg

"Pooh Bear" wrote in message
...
PanHandler wrote:
Specs: Logic PLX4800
MAX Power @ 2 Ohm 350W x 4 CH
RMS Power @ 4 Ohm 175W x 4 CH
S/N Ratio 102 db
THD (4 Ohm) 0.01 %
Freq Response + 1.0 db 10 Hz - 35 KHz *

So if the 'rms' power is 175W - where does 350 come from ? I'll bet it's
the
typical 'peak instantaneous' power so beloved of ICE makers.
So equivalent to a 'normal' 4 x 175W amp i.e. 700W.
But furthermore It looks to me like it's rated into 2 ohm loads. Unless
those
cabinets are 2 ohms and I bet they're not - you're likely looking at ~
100W into
4 ohms / channel or maybe 60W into 8 ohms.

They are 2 Ohms.

Suppose the speakers are indeed 4ohms. That's ~ 400W rms continuos power
but
actually the dynamics of music mean that the averaged power is likely to
be more
in the region of 200W.
Add in the amplifier's efficiency and the 25A peaks now start to make
sense.
In short it isn't a 1600W or even a 1400 W system but more like 400W.

The graphics on the amp sure look pretty though. :-)

I suppose this could go on forever, and for the most part I do buy your
comments (and skepticism). In discussions like this with friends I always go
back to "Sounds pretty damned good at what it's supposed to do".

In article , Pooh Bear wrote:


PanHandler wrote:

Regardless, at near the pain threshold, the amp only draws
approximately 25 amps on bass peaks. The speakers are quite efficient @ 92
db.

You're not going to get anywhere near the pain threshold with that lot unless
it's constantly clipping of course in which case it *would* be painful to
listen
to.

Why would anybody want pain?

greg

In article , Pooh Bear wrote:


Dave Platt wrote:

Does the manufacturer state that the amp is rated at 1400 watts of
continuous power? or do they just say "1400 watts" and not give the
conditions of the test?

In car audio is typically rated with 'peak rating' and 10% distortion. The
power
ratings are no way comparable with hi-fi gear for example. To make a more
normal
comparison you need to divide by 2-3 minimum typically.

I think its a shame the car audio companies have not inserted
120 vac supplies to their amps. Whole new lines
of inexpensive amps could be drawn. It would be a fairly simple matter
to use a DC to DC voltage up converter instead of a voltage down converter.
I don't think there would be any space disadvantage except
for the input rectifier and caps.

greg

"Pooh Bear" wrote in message
...
Murray Peterson wrote:
David Nebenzahl wrote in
.com:
I think there's a semantic or comprehension problem here (and not on
the part of the O.P.). He or she says they have a 1400 watt amp; let's
take their word for that.
Why? Take a look at this pictu
http://flickr.com/photo_zoom.gne?id=162367000&size=o
If you look closely, you will see that his power supply is a Pyramid PS-
36KX. That unit provides a constant output of 32 amps at 12V.
But where's the amplifier ?

In the compartment directly behind the folding laptop shelf. The laptop
serves up over 40,000 mp3's via an external 250 GB HD.

"GregS" wrote in message
...
In article , Pooh Bear
wrote:


PanHandler wrote:

Regardless, at near the pain threshold, the amp only draws
approximately 25 amps on bass peaks. The speakers are quite efficient @
92
db.

You're not going to get anywhere near the pain threshold with that lot
unless
it's constantly clipping of course in which case it *would* be painful to
listen
to.

Actually, Graham wrote the second paragraph. I use Outlook Express and
sometimes the thread really gets convoluted with all the reply markers, etc.
Joe

David Nebenzahl wrote in
.com:

Murray Peterson spake thus:

David Nebenzahl wrote in
.com:

I think there's a semantic or comprehension problem here (and not on
the part of the O.P.). He or she says they have a 1400 watt amp;
let's take their word for that.

Why? Take a look at this pictu
http://flickr.com/photo_zoom.gne?id=162367000&size=o
If you look closely, you will see that his power supply is a Pyramid
PS- 36KX. That unit provides a constant output of 32 amps at 12V.

Of course, at 35 A @ 12 V, he or she isn't going to get 1400 watts
out of it. But that's another matter.

Certainly not one of semantics. 32A * 12V * .707 = 271 watts at
perfect efficiency. A "real world" amp is more liekly to produce
something closer to 200-250 watts output with that power supply.

That doesn't change the fact that the *amplifier* could be rated at
1400 watts--regardless of whether the power supply can provide that
power or not. See what I mean?



Oh -- I understand what you were trying to tell me now. Mind you, I
would like to see a car amp honestly rated at 1400 watts -- those would
be some seriously hefty copper input connectors :-)

--
Murray Peterson

PanHandler wrote:

I use Outlook Express

Oh, so you DO like pain. Unfortuanately, most don't, and that
quote-mangling crapware of your gives it.

"dizzy" wrote in message
...
PanHandler wrote:
I use Outlook Express

Oh, so you DO like pain. Unfortuanately, most don't, and that
quote-mangling crapware of your gives it.

But it does do spell checking. :-)

PanHandler wrote:

"Pooh Bear" wrote in message
...

You're not going to get anywhere near the pain threshold with that lot
unless it's constantly clipping of course in which case it *would* be
painful to listen to.

By 'near', I meant it was just too loud for comfortable listening the room
it was set up in. It doesn't do badly at all.

I've experienced SPLs in the near 130dB region ( very briefly ) . If the sound
quality is good it's not actually painful but simply awesomely loud ! On the one
specific occasion I was there when we ran up a system capable of such SPLs I
actually got a temporary skin rash from the spl ( not uncommon btw ).

My next experiment will be to parallel a couple good batteries and see what
it's really made of.

Since that won't increase the voltage it will accomplish very litle.

Graham

Pooh Bear spake thus:

PanHandler wrote:

My next experiment will be to parallel a couple good batteries and see what
it's really made of.

Since that won't increase the voltage it will accomplish very litle.

Since it will increase the *current* it ought to accomplish something, no?


--
Any system of knowledge that is capable of listing films in order
of use of the word "****" is incapable of writing a good summary
and analysis of the Philippine-American War. And vice-versa.
This is an inviolable rule.

- Matthew White, referring to Wikipedia on his WikiWatch site
(http://users.erols.com/mwhite28/wikiwoo.htm)

"David Nebenzahl" wrote in message
.com...
My next experiment will be to parallel a couple good batteries and see
what
it's really made of.

Since that won't increase the voltage it will accomplish very litle.

Since it will increase the *current* it ought to accomplish something, no?

If the present battery can't supply sufficient current, yes.

MrT.

Mr.T spake thus:

"David Nebenzahl" wrote in message
.com...

My next experiment will be to parallel a couple good batteries and see what
it's really made of.

Since that won't increase the voltage it will accomplish very litle.

Since it will increase the *current* it ought to accomplish something, no?

If the present battery can't supply sufficient current, yes.

No battery; the O.P. says it's running on a 12v, 35A power supply. 2
batteries oughta trump that.


--
Any system of knowledge that is capable of listing films in order
of use of the word "****" is incapable of writing a good summary
and analysis of the Philippine-American War. And vice-versa.
This is an inviolable rule.

- Matthew White, referring to Wikipedia on his WikiWatch site
(http://users.erols.com/mwhite28/wikiwoo.htm)

"David Nebenzahl" wrote in message
.com...

No battery; the O.P. says it's running on a 12v, 35A power supply. 2
batteries oughta trump that.

That's what I thought. I'm taking the outfit to a remote campsite over the
weekend and will be able to really push it. It's gonna **** or get off the
pot.

David Nebenzahl wrote:

Pooh Bear spake thus:

PanHandler wrote:

My next experiment will be to parallel a couple good batteries and see what
it's really made of.

Since that won't increase the voltage it will accomplish very litle.

Since it will increase the *current* it ought to accomplish something, no?

If the load doesn't *need* any more current it can't draw any ! I = V/R and all
that.

Graham

"Mr.T" wrote:

"David Nebenzahl" wrote in message
.com...
My next experiment will be to parallel a couple good batteries and see
what
it's really made of.

Since that won't increase the voltage it will accomplish very litle.

Since it will increase the *current* it ought to accomplish something, no?

If the present battery can't supply sufficient current, yes.

Since car batteries are good for 100s of amps whilst cranking, I think the
advantage of 2 in parallel will be limited.

Graham

David Nebenzahl wrote:

Mr.T spake thus:

"David Nebenzahl" wrote in message
.com...

My next experiment will be to parallel a couple good batteries and see what
it's really made of.

Since that won't increase the voltage it will accomplish very litle.

Since it will increase the *current* it ought to accomplish something, no?

If the present battery can't supply sufficient current, yes.

No battery; the O.P. says it's running on a 12v, 35A power supply. 2
batteries oughta trump that.

Only if he's seeing the voltage meter droop on load.

Graham

PanHandler wrote:

"David Nebenzahl" wrote in message
.com...

No battery; the O.P. says it's running on a 12v, 35A power supply. 2
batteries oughta trump that.

That's what I thought. I'm taking the outfit to a remote campsite over the
weekend and will be able to really push it. It's gonna **** or get off the
pot.

When it's on the power supply do you see the output voltage drop when it's loud
?

Graham

PanHandler wrote:

"David Nebenzahl" wrote in message
.com...

No battery; the O.P. says it's running on a 12v, 35A power supply. 2
batteries oughta trump that.

That's what I thought. I'm taking the outfit to a remote campsite over the
weekend and will be able to really push it. It's gonna **** or get off the
pot.

You'll be surprised how quiet it'll be outside.

Graham

"Pooh Bear" wrote in message
...

When it's on the power supply do you see the output voltage drop when it's
loud

Good morning Graham. I don't see any wavering on the PS volt meter, which I
set at 13.8 V. I'm not an electronics whiz, but I'd *ass*umed the PS would
maintain the setting; otherwise why provide for adjustment?
Joe

"Pooh Bear" wrote in message
...

You'll be surprised how quiet it'll be outside.

I had the outfit there last weekend, but it poured all day and with the wind
and rain it was too noisy and wet to spend much time with it. The few
minutes it ran, it seemed OK in terms of SPL.

In article , Pooh Bear wrote:


"Mr.T" wrote:

"David Nebenzahl" wrote in message
.com...
My next experiment will be to parallel a couple good batteries and see
what
it's really made of.

Since that won't increase the voltage it will accomplish very litle.

Since it will increase the *current* it ought to accomplish something, no?

If the present battery can't supply sufficient current, yes.

Since car batteries are good for 100s of amps whilst cranking, I think the
advantage of 2 in parallel will be limited.

Having more battery gives longer life since a lower discharge rate
has a higher return efficiency. Its also easier on the battery supporting longer life.

greg

PanHandler wrote:

"Pooh Bear" wrote in message
...

When it's on the power supply do you see the output voltage drop when it's
loud

Good morning Graham. I don't see any wavering on the PS volt meter, which I
set at 13.8 V. I'm not an electronics whiz, but I'd *ass*umed the PS would
maintain the setting; otherwise why provide for adjustment?

It would drop if you drew more than it's 35 Amps though. It would 'run out of
regulation'. Since that's not happening you can be sure that the DC input power
does not exceed 483 W. Using a typical figure for Class B efficiency that
transaltes to 300W peak of audio output.

Graham