I had the mackie 450'scut out on my [embarrasing I might add] on stage more then a few times when laid down as desined due to the horizontal heat fin positioning, but it also happened when on poles also. This is a big problem. I have now installed fans inside my Barbettas Sona 32c's that eliminate this proble entirely...seems Mackie should take the hint also in future designs if any.

Donny, are your fans specifically(produced/sold by Barbetta) to fit inside the Sona32c's? How difficult was it to install? If they're not Barbetta authorized fans, is there any risk of voiding the Sona32c warranty? Also curious if by any chanace the current Sona32s now come with cooling fans. - Scott

Scott,

The Sona-32-Cs now come with large, quiet computer fans suspended inside the cabinets, another vent near the top, and unless you place your ear against the vent, you cannot hear them running. As for the older models, they were not equipped with fans and they only had a single vent. The fans in Donny's were installed by me, along with a second vent. The fans will not void the warrenty, and since their installation, he has not experienced a single overheating problem, even when playing outdoors on the hottest day of the year.

I had a first hand look at the Mackies several weeks ago, and even with the volume turned down and the speaker on a pole, the heat sink got pretty warm. It's a poor design at best. The Mackies were among my considerations when I was shopping for lighter, powered speakers. When turned up, the heat sink became too hot to touch. That's the reason I ruled them out and went with the Barbettas.

Cheers,

Gary

[This message has been edited by travlin'easy (edited 08-20-2003).]

Roel, you are correct with regard to matching speaker impedance to the amplifier, but only with tube amps. Doesn't apply to the constant voltage type of solid state amp in use today which has zero output impedance (in theory). The limiting factor is the current that the output stages are able to supply. Most designers cut corners to save money, especially if you don't really need the performance. This is why you don't get double the output when going from 4 ohms to 2 ohms. The current limiters take over at high outputs to protect the output transistors.

Bryan

Dave, Donny,

do you guys think it might be a combination of humidity and heat?
Here in CA we have very dry heat.

Eric

I'm going back to laying brick.

[This message has been edited by brickboo (edited 08-20-2003).]

[This message has been edited by brickboo (edited 08-20-2003).]

I did that today--can't say it was much fun. Only had to put 140 pavers into the sidewalk in 94 degree heat with 80 percent humidity. Boo, if you lived closer, you would have got the job.

Cheers,

Gary

eric......no chance ....when you push them ther cut off...only once did it happen outside in the shade under a tent...the other times it was on stage inside.

watts @ 2 ohms
watts @ 4 ohms
watts @ 8 ohms

Just remember the ohms load of speaker to amplifier is not constant. The ohms load varies with frequency. Even a 8 ohm speaker load to amplifier can drop below 2 ohms or upto 16 ohms at a certain frequency.

It is foolish to run lower ohm speakers just to obtain a higher output volume than the Amplifier maker suggests.

Graham UK

Graham

While that's a good point and something to watch, not all speakers are created equal. My speakers have a flat impedance of 8 ohms, dropping to 6 ohms above 5000Hz due to the tweeter (where there's not much output anyway). And they're resistive at all frequencies except at resonance in the woofer. You pays your money and takes your choice.

Bryan