Orion Clone driver height question

[santiu]

Hey everybody. Brief history, originally I was just going to make a dipole woofer, but I ended up with some more drivers so I figure I'd just combine it all to make an big orion clone.

What I'm wondering is about the mid-tweet vertical position. I have the PMT1 drivers, so basically I'm just stacking the PMT1 on top of the dipole woofer and putting on some side like the Orion. Is there an optimal position for the Mid-Tweet combo? Right now I have it modeled so that the center between the mid and tweet is at my ear level when sitting on my couch (~41")

So yeah, that's it. Just wondering how high to put the mid-tweet panel (which is just a PMT1).

Attached are some pictures of my model. I'd like to come up with some more creative sides to hold it together, but I'm drawing a blank right now...

[santiu]

p.s. the back board that holds the woofer in place is not shown

[santiu]

but it is shown here

[AJinFLA]

In case you missed it:

ORION owners have access to helpful information and updates. The design is stable and has proven itself over a number of years now, but I still keep my eyes, ears and mind open for worthwhile revisions.


These are the specifications:

Open baffle cabinet
Outside dimensions: Height 46.25" - Width 13"
Depth 2" at top, 12" at base, 16" at 14" up
Weight 60 lb (27 kg)
3-way active speaker system
Crossovers at 120 Hz and 1440 Hz, both LR4 (24 dB/oct)
Crossover/Equalizer using two ORION ASP printed circuit boards
Tweeter - Seas T25CF002 - No, not a ribbon -
42" up , no 2.8 kHz notch filter as in PHOENIX
Preferably no grill to cover the tweeter
Midrange - Seas W22EX001 - No, not a smaller diameter -
Front mounted to baffle, no spine, but see Revision 0.1
34.5" up, 5 kHz notch filter
Woofer - two Peerless 10" XLS, 830452
Push-pull mounted in H-frame of 11.5" x 11.5" x 24.5" OD
Each driver with its own >60 W amplifier
etc.

Those are the center line heights of the drivers.
The gap between your main panel and woofer section would be highly undesirable.

Cheers,

AJ

[santiu]

Originally posted by AJinFLA
In case you missed it

lol... yeah, I actually totally missed that ... DOH! I get lost on his website there's so much info

Originally posted by AJinFLA
The gap between your main panel and woofer section would be highly undesirable.

aw... bummer. I just came up with some new sides I like (it's a slow day at work), but it keeps the gap there. What happens thats so bad when the gap is there? I'm just trying to understand as many issues as I can when building a speaker like the Orion. Would it be better to build the PMT1 and woofer as two separate entities? I sort of like the idea of just having 2 big speakers, rather than 4 smaller ones.

[sdclc126]

How about building the entire speaker taller, like a tower, by adding a base below the woofer module? The mid/high module would then be at your desired height, without changing the critical Orion dimensions. Someone correct me if Linkwitz advises against this.

Or, consider adding another midrange to the "gap" you have in your current design, making an MTM, as in Linkwitz' Phoenix. In this arrangement the tweeter would be at ear level, but the mid frequencies would appear to be there also.

This of course makes for more complex and expensive design and possibly require crossover mods, but others have built Orions this way with favorable results. There is (or was?) a link somewhere on SL's site to just such a design, called the "Bob" loudspeaker - I think he used different woofers, but the mids & tweet are the same as best I can remember, just in an MTM arrangement.

[santiu]

Sorry to resurrect this, but I'm trying to figure this out

Originally posted by AJinFLA
The gap between your main panel and woofer section would be highly undesirable.

can someone explain this to me? I just emailed Linkwitz for some advice on whether to stack the PMT1 on top of the woofers or make an Orion type "enclosure", and he said that stack the PMT1 on top of the H-frame is fine, and that a small stand underneath the PMT1 to bring it up a little higher would give breathing space around the PMT1.

I'm very new to speaker building, so I don't understand what's going on. Could someone help explain what downsides there are to having a "gap" between the main panel and the woofer section (or send me a link that I can read up)?

thanks a bunch

[Davey]

I don't think the gap would be a problem. Indeed, the PMT1 is very similar in dimensions to the main panel of your rendering.

I think what AJ was concerned about was front/back cancellation since that distance is rather smaller on the lower edge of your panel than it is to the sides.

Aesthetically, I would like the look of your speaker with the gap filled in, but that's just me.
Acoustically, I don't think you'll pay much of a penalty for doing that. The horizontal polar response is the most critical, and your design seems very close to the basic Orion shape which is good.

Cheers,

Davey.

[sdclc126]

If Linkwitz says it's OK it is. You can have the gap, or fill it in just using a taller panel - personally I think that would look better.

[santiu]

Thanks a bunch for your replies guys

The more I think about it, the more I'm leaning towards just completely copying the Orion shape (i.e. filling in the gap). Still a little resistant since it would be nice to have a unique design, but the Orion does look nice.

Again, thanks! I should start cutting wood the weekend after next (assuming nothing comes up, but some how something always comes up ), so I'll keep you all posted!