[Hidden-tech] Looking for Stereo Setup Assistance

[Robert Heller]

At Tue, 18 Apr 2017 15:49:41 -0400 Michael Muller <tech at montaguewebworks.com> wrote:

> 
> 
> Hmmm... I thought wattage was wattage, no matter the cone size. It's 
> totally possible that the stereo is under-powered for the speakers, but 
> will they really just fuzz out when I get to 1/3 of the possible power 
> output?

Well the speakers are rated at 10x the power output of the amp (175w vs 18w), 
so sure the amp is probably underpowered.  Cone size relates to freq. 
response and/or how much energy the speaker can transfer (in layman's terms: 
how loud they can be -- bigger speakers are louder at lower freqs).  The 
engery transfer has to come from somewhere.  As the volume goes up, the engery 
transfer increases and the power demand on the amp goes up.  At some point the 
engery transfer exceeds what the amp's output stages can handle and things go 
south down in the transistor junctions or gates -- thermal overload / runaway 
(the amp almost certainly has some sort of overload protection to keep the 
magic smoke from escaping -- probably something like a current limiting 
resistor, which will cause clipping, aka fuzz).

> 
> I do have a full stereo I can swap out to see if there's a difference.
> 
> Mik
> 
> Mik Muller, owner
> Montague WebWorks
> 413-320-5336
> http://MontagueWebWorks.com
> Powered by ROCKETFUSION
> 
> On 4/18/2017 11:49 AM, Robert Heller wrote:
> > At Tue, 18 Apr 2017 10:54:53 -0400 Michael Muller <tech at montaguewebworks.com> wrote:
> >
> >>
> >>
> >> Hey all,
> >>
> >> With the coming of the good weather, I'm getting ready to set up my
> >> backyard for outdoor sound.
> >>
> >> I already have four Advent Marbl speakers and a decent car stereo
> >> hard-wired to a strong DC power supply.
> >>
> >> If I put the volume above 50% the speakers just put out fuzz. Total
> >> crap. And this is with only two of the speakers connected. So...
> >>
> >>    * Is it the speakers? (175w RMS)
> >>    * Is it the wiring? (16 gauge)
> >>    * Is it the stereo? (18w RMS)
> >>    * Is it the power supply? (12vDC* 10A = 120w)
> >>
> >> I'm looking for someone who works at a car stereo installation place, or
> >> who really knows about this kind of stuff down to the technical wattage,
> >> ohms, wire-length and gauge, etc. level.
> > I don't know much about car stereo, but working with the Full Moon Coffeehouse
> > sound system (with advice from Klondike), it seems like your car stereo is not
> > putting out enough power to drive the speakers.  Are these Advent Marbl big
> > indoor type speakers?  If so the *little* car stereo is not really designed
> > for that.  It is for the *little* dashboard speakers typical in a car.  The
> > "fuzz" output suggests that the stereo's output drivers are going into some
> > sort of overload state.
> >
> > Is there some reason you can't use a proper high power (eg ~200W or something)
> > home stereo system?  I fully understand using big speakers outdoors -- they
> > would be needed to cover the space, but that means you need a powerful enough
> > amp to drive them.
> >
> >> Ultimately I want to drive eight speakers from one unit, using the
> >> "front" and "back" settings on the car stereo, and the "surround"
> >> line-out on each of the four main speakers. See the attached PNG file if
> >> you're interested.
> > Be carefull of putting too many speakers on any *one* output: you will hit
> > impedance and power load issues.
> >
> >> https://www.ebay.com/p/Advent-Marble-Main-Stereo-Speakers/69600291
> >>
> >> https://www.crutchfield.com/S-xO4AMhTXX8Q/p_500CDA9883/Alpine-CDA-9883.html
> >>
> >> Please contact me if you're interested in helping me on-site
> >> (Greenfield), or pass this along to someone you may know who knows about
> >> this stuff.
> > I'd suggest John "Klondike" Kolher of Klondike Sound.
> >
> >> Thanks,
> >>
> >> Mik
> >>
> >>
> 
> 
>                                           

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