A bad idea? Omni-ish TL


2014-03-24 9:52 pm
First let me say I just love FR speakers. They just sound cleaner, at least when using real life (afordable) components. The only thing that I don't like is finding the "chair sweetspot" for listening. They are just too narrow sometimes. Or is it just me?

What I'm wondering is, what would happen if I made a kind of a TL enclosure with the driver facing upward, and using a 3d pritned reflector to widen the output a bit. Not neessarily make it full omni, but wider than what these drivers usually produce. I know the efficiency of these speakers would be worse than when used in a conventional enclosure, but what would some other downsides be? I need something to discard the idea, or theory of acoustical reflections. :)
A reflector doesn't just add delay. A reflector adds wildly inconsistent delay across the frequency range, and wildly inconsistent redirection across the frequency range. Let's assume you get lucky and it doesn't completely ruin the frequency response, you're pretty much guaranteed to have a lot of submillisecond delay right in the critical detail range. That won't sound good.

Since an individual's subjective perception is a total crapshoot and based as much on expectation as the actual experience, you might like the sound. Objectively however, it has measurable qualities that most of us would consider bad for a speaker system.
Let me toss an idea or two into the mix.

I've designed and built several bipolar mass loaded transmission line (MLTL) speakers (do a search for 'bipolar MLTL' on this site to bring up a few URLs). A bipolar speaker uses drivers typically pointed forward and rearward. The drivers are fed in-phase so that the speaker radiates energy forward and backward in the room. The radiation patterns are wide and in room what you hear is a nearly omni-directional presentation. These speakers would typically be located away from the walls so that reflections are not heard as reverb within the room. Normally the spacing would be at least 3-4 feet away from the wall behind the speakers.

Another bipolar variant is Planet 10's speakers that have a driver facing the listener with another one on top of the enclosure. Thus the projected sound would create a presentation which may take up less space in-room.


2014-03-24 9:52 pm
Thanks for your input, guys. Discarding the idea. It wasn't so much about overcoming the narrowness, as meditating on a possible project. :)

I guess it's time for a new "bad idea" until a good one comes my way. :)
I'm thinking concrete enclosure, or maybe something very low profile and round edged wall hanging thing... Well, we'll see. :)

i made a few double horns, more or less omni without disadvantages:
look my double horns:


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