Axiom Home Page Forums General Discussion Technical Questions Lying a speaker on it's side (M3's in particular)

Newbie Alert!

Forgive me if I'm not using certain terms correctly or am missing a fundamental rule in what I'm trying to describe.

I have three M3's (just got them yesterday!) serving as my LCR channels and currently have ALL speakers on their sides due to space and WAF considerations. The center is sitting above my TV, while the left and right speakers are sitting on a shelf level with the base of the TV.

From reading some articles and posts I know that there are issues with 'lobing' (what the heck is that?) and dispersion when lying a speaker on it's side, but all the material I can find on the web relates to enclosures with multiple similar drivers i.e. MTM, MMMM, etc.

Do these issues extend to MT designs as well? What am I supposed to hear when 'lobing' occurs? I have a good idea on dispersion differences, but aside from that, what should I be listening for?

BTW, I did do some extremely informal testing last night, and did hear a difference, but need more time to affirm my findings.

Brian, for the best results with speakers which have the drivers aligned vertically they should be positioned vertically. This isn't to say that playing them in a horizontal position is a disaster, but the widest and smoothest horizontal dispersion occurs with them standing(proudly)upright.

If you stand it upright, it'll tell the truth.

First if you have to ask what to listen for then you are not hearing any serious lobing.

The lobing you’re reading about happens when the output of two speakers drivers playing the same thing or the output of one driver and it’s reflection off a nearby object like a wall interfere with each other. Just like waves from two rocks thrown in a pond the sound waves either cancel or reinforce each other causing higher or lower sound pressure (loudness) depending on where you are sitting in relation to the source of the sound.

So what you’re listening for is a change in loudness as you move around your listening position. If you want to hear what it sounds like the best way is to use a wide band test tone like on a calibration disk. Hook two of the speakers up to the same channel and play the test tone. Put the speaker next to each other and back up to your listening position and move from side to side. You may have to move the speakers apart some to get an interference pattern you can hear. When you hear the loudness go up and down as you move your head from side to side you are hearing the effects of lobing.

I’ve done very extensive listening test while trying different dual center channel configurations and have only heard lobing once when I moved to M22 speakers right next to each other while they were both hooked up to the center channel.

Putting a speaker like the M3 on it’s side will not cause lobing as the two drivers are not playing the same frequencies (except a slight overlap around the crossover point).

The real issue with putting speakers on their sides is that it changes the horizontal dispersion pattern they were designed for to the vertical plane. This becomes a bigger issue when a speaker has more drivers and is longer like an M80 than with a smaller speaker with 2 drivers like the M3. As you move back from the M3s they will start to act more like a point source and I doubt from several feet away if you could tell if they were standing up or on their sides when listening with your eyes closed.

In short you will here no more lobing with your M3s on their sides than you would standing them vertically in the same location. Laying them on their sides should not make a noticeable difference unless you’re up close to them.

grunt,

That has to be the best explanation I have read yet! Thank you very much!

Yes, there is no change in loudness as I move around the listening area. I have also found that dispersion seemed unaffected as I switched back and forth between alignments.

The only differnce that I heard (last night) was due to the lack of consistent toe-in. A mistake on my part that I confirmed during tonights listening session.

Mahalo!

Brian