Another corner line array, 28 TC9FD18

[Crumboo]

If you can get it to work like that, it would be awesome! The trick you used on the Vifa line to tweeter might work on the sub to Vifa line as well for an even more smooth directivity.
Smoothing out the dip at 200 Hz even further, but this does seem like a winner.

I think I should add my subs in my sims as well, just to play with them. What kind of directivity files did you use for the sub? Did you generate it from a 12" driver in Vituix?

I remember seeing a 16 ohm Vifa TC or TG series once, but they don't show up in stores. The 2 ohm is a bit too low for safety.

Thanks wesayso!
Actually, the subs are just generic drivers in Vituix - flat response and omnidirectional at all frequencies. So there is more to be done in the low end. I think I have directional data traced from the data sheet of these drivers somewhere, so I will try to put that in. I am pretty confident that the low end could be managed somewhat easily. Phase tricks would probably work here as well.

By the 2nd element, I meant the 2nd out from the tweeter. You would have tweeter, close in MTM driver pair, line arrays to floor & ceiling. And those line arrays would be frequency shaded - which is where you ended up.

Good work!

Thanks nc535!

@crumboo, just a friendly word of advise...
With results this good, don't forget about the (close by) side walls. The above would work wonders on floor and ceiling to create more than acceptable results for seated and standing in-room results. However to get the max out of it, the side walls, that for a large part will be parallel to the arrays, will have a huge influence too. So do factor that in somehow. At least to avoid (very) early reflections of close by boundaries.
That will be something to factor in, as it will be roughly equal distance to all of those array drivers, which makes it less forgiving.

I haven't forgot about the horizontal behaviour! You have helpfully pointed this out on several occasions! As you know I have some special circumstances to deal with here as the speakers must be tucked into the corners of the room, with that book shelf on the side. I did some experiments earlier that convinced me that it is possible to reduce the early reflections. Now that I am beginning to settle on the vertical arrangement of the drivers and that behaviour, I will again turn to this matter. I have plans for a few more experiments

 

[Crumboo]

Continuing tweaking...

From the previous simulations I wanted to rearrange the drivers to get a reasonable impedance (it was in the range of 2 Ohms there). Also, I wanted to, if possible, get rid of those huge coils.

I generated directivity data for the 12" subs using Vituix diffraction tool to get a more realistic simulation in the low region. I also wanted to improve the vertical directivity in the lower range, which could be done by adjusting the crossover point and filter slopes.

As I was tweaking, trying and testing different sets of parameters I noticed that I could get a better, smoother response the lower I cut the outermost sets of Vifas. And then, when they were cut of so low they contributed very little to the overall SPL - so I simply removed them! Now there are only 8 of them left, 4 above and 4 below the tweeter...(hm...I started with 28!). Now I got this big space between the Vifas and the 12" drivers...what to do? Adding another 12" drivers for a total of 4 per side? Well...I guess one can't have enough margin in the LF region??

Schematics:

SPL curves:

Vertical polar:

SPL, power and directivity (in seated position):

And in standing position:

 

[wesayso]

If this can do what you want it to do, don't add anything . It will probably mess up the results instead of making them better, but you could try at the cost of using some time.

So basically, you have a WMTMW, or more specifically, a WmmmmTmmmmW . A modern day Dunlavy type speaker. (but with a wider vertical window)

If the horizontal plot looks as cool, and the maximum output (headroom) is to you liking, I think you're zooming in towards a winner here... If you work at it just a little bit more to fix the 200 Hz crossover point at seated position (or just EQ it out at the expense of the standing position) it does seem like it works over a wide area.
** don't forget to check intermediate positions too! **

What's the level of absorption on the floor/ceiling?

 

[Crumboo]

The level of absorption is set on 6 dB in these plot. Interesting to see how that corresponds to reality. Your measurements showed it to be around 4 dB if I remember correctly?

Horizontals are not that exciting to look at :

This is simulated as a corner (quarter space), so only +/- 45 deg. Right now I'm building a "fake" corner to my experimental baffle so I can try some damping an look at reflections at different angles.

 

[wesayso]

I almost forgot about the corners... I was already envisioning a cute shape like this:

(mirror the bottom end to the top for my complete vision , to house the 12"s)
Big on top and bottom, sleek,slender waist in the middle...
Those are the (very interesting) Lexicon speakers by the way.

 

[wesayso]

So 12 Vifa's per side, plus all other drivers and you're done.

I remember reading this:

By the way - placed an order for 70 Tc9FD yesterday!

Does this mean you can have line array surrounds?

 

[Crumboo]

Yes I know... I have use for some of them in other projects in the future: small surround speakers for the TV-set upstairs and small "full range" speakers in the four corners of the dining room. But there are still lots and lots of drivers left...

Ambience speakers for this setup will be built but I haven't any finished plans for this. The idea now is that the setup will be used for home theatre as well (a place for a big TV in the book shelf) and somehow I would have liked to have the ambience speakers double as surround speakers for that purpose. And that is, as I believe, a different thing. The ambience speaker should not provide any direct sound to the listening position - only through (multiple) reflections - as I understand it. But this isn't the case for surround speakers in a home theatre setting, or is it?

Then I'm not sure how to route and eq the sound for those to situations (stereo and home theatre). The music source is a Bluesound Node that goes into the PC for filter/EQ and then to a multichannel DAC. The TV source will be an Apple TV. I have no home theatre receiver, and would prefer not to have one to keep it clean. So maybe, for now at least, I simply skip the home theatre decoding and just go stereo (with ambience) for the TV as well...