Axiom Home Page Forums General Discussion Technical Questions Mixing 4 ohm centre with 8 ohm left and right?

what happens to the sound when you change a speaker from 6 to 8 ohms mojo? I've been listening to my 5's in 8ohms. Does axiom make a speaker terminal for the on wall brackets?

If you change the receiver setting to 4 Ohms, the voltage for the amplifier circuits is decreased. The amplifiers will clip sooner, robbing you of dynamics, soundstage, imaging and emotional impact. The 4 Ohm setting increases the risk of blowing your tweeters because clipping increases thermal stress in the tweeters. It does so because high frequency content is introduced from the harmonics that comprise the clipped signal. This high frequency content carries more energy than typical music and ignites the tweeters.

The reason receiver manufacturers have a 4 Ohm setting is so they can pass safety certification tests and stamp their receivers as 4 Ohm capable. They are indeed 4 Ohm capable but to a lower performance standard. If a receiver puts out 100W per channel into 8 Ohms, a 4 Ohm load would squeeze 200W out of it. But then, the heat sinks on most receivers would get too hot and the safety certifier would give it a fail. The 4 Ohm switch prevents this overheating by robbing the speaker of power. It's not inconceivable for a 4 Ohm speaker to sink only 40W max from a receiver rated 100W into 8 Ohms when set to 4 Ohms.

Practically, the 8 Ohm setting for a 4 Ohm speaker is of no concern unless you listen at very high levels. If so, the best thing to do is get an amp like an ADA. Any ADA doubles its output power when the load is decreased from 8 to 4 Ohms. But even if you don't, a well-designed receiver will self-protect. Of course if it's always self-protecting, you need an amp for sure.

My Onk has multiple modes of protection. It starts to compress the output and if I keep pushing it, it shuts the channel down. I like the ADA protection better. It doesn't try to fool you by compressing the output. It keeps going until it hits its limit and then gently shuts the channel off. It brings it back when the problem goes away.

Regarding speaker terminals for the OW, Axiom can make the speakers with terminals but not the brackets.

What do you think about playing the 5ow's at 6 ohms?

Do you think the smaller M2ow need the back wall or will FMB work?

Don't do it. Why rob them of power?

The M2OW definitely need to be against a wall. I chastised Ian for how shitty they sounded and then took it all back and sang hosannas after crucifying them.

Why do you want to FMB them? How off-axis will they be bolted against the wall?

And if you have a newer Denon turn energy saving off (and its onscreen graphic.)

As for on wall vs FMB, google “Baffle Step”. Use speakers as designed for best result.

https://www.css-audio.com/single-post/2018/09/14/Understanding-Baffle-Step-and-Diffraction

"If you were to lay a circle centered on both the x-axis and y-axis and trace around it’s perimeter, you would have gone... 4Pi when you get back to your starting point."

No. Once around a circle is 2pi which is the ratio of the circumference to the radius of the circle. 4pi refers to a sphere which is the ratio of the surface area to the square of the radius. 2pi is the surface area of a half sphere.

4pi is called full space. 2pi is called half space. Both refer to how radiant intensity is measured. When a bookshelf or floor-stander is spinoramad, the radiant sound power is computed from the intensity incident on the area of a sphere. When a wall-mount is spinoramad, the radiant sound power is computed from the intensity incident on the area of a half sphere. This radiant sound power is referred to as the "sound power" curve. It's a curve because the sound power strength varies with frequency.

One thing I don't understand is why some manufacturers install the tweeter faceplate flush with the baffle and others, like Axiom, stand it a bit proud. Perhaps this is a tradeoff between reduced baffle edge diffraction and higher faceplate edge diffraction? The faceplate edge diffraction would take place at higher frequencies than the baffle edge. Perhaps diffraction at higher frequencies is less objectionable or easier to compensate for.

Which mojo posted this? I'm confused. I just want the M5ow's to purr like the other axioms.

There is only room for one Mojo on this planet and some would say that is one too many.

They'll purr if you crucify them on their wall-mount bracket.