10" Coax in OB

[inrank]

on the full range thread, i have been discussing a Full-Range driver in OB, and mabye with some bass support, what about this though...

its basically an Adire HE10.1 with an extra bass speaker!

Eminence Beta 10CX with the Eminence APT 50 Super tweeter and a Eminence Alpha 10 for bass support using the pre-made PXB33k5 (500Hz/3.5kHz) crossover all in OB? (OB around 1000mm x 400mm)

http://www.bkelec.com/Pro/Drive_Unit...e/Beta10cx.htm
http://www.bkelec.com/Pro/Drive_Units/Eminence/APT.htm
http://www.bkelec.com/Pro/Drive_Unit...ce/Alpha10.htm

easy as i dont need to make the crossover, would this give me a 'live' sound?

could use it for partys aswell

would it run of a 70W Primare A20 amp?

[mashaffer]

Seems like a decent approach in general however I would strongly consider a different driver for the helper. Both the Beta coax and the Alpha 10 have a pretty low Qts for OB. I would suggest the Alpha 15 as a better alternative. It should be good for a solid, smooth 40Hz on a reasonable sized baffle.

You could start with the Eminence crossover and experiment with you own later. You want to cross over as high as possible while still giving good integration. In OB you may be able to cross higher because beaming will be less of an issue than it would be in a closed box.

I look forward to your results as I am considering a similar approach for a HT system suplimented by really big TL subs.

mike

[inrank]

well, i cant really have a 15"er, too big, but i dont need that much bass, i would be perfectly happy with 60Hz solid...

i think i would go for the pre-made crossover as i have not made one before and as you said, i can change it later, and 3.5Khz is the recomended crossover point of the coax.... from the 10CX and the APT50

has anyone else done simmilar?

and would these 'play' quiet, as in will they sound dynamic and expresive at lower volumes?

[johninCR]

I have the Adire HE8.1's, the same unit but with the 8" coax. They sounded somewhat sterile to me in the recommended BR. I discovered OB's about 2yrs ago, and decided to try them in an open alignment. Using four 6" high Q cheapies per side as bass fill, the results were excellent, a night and day difference in terms of rich and natural sound. My 9yro daughter even asked why one sounded so much better than the other in a head-to-head comparison. My only reservation for you is for party use. You'll need to use Linkwitz's SPLmax spreadsheet to verify your bass augmenter requirements.

Here's a pick of what I came up with using real wood:

[el`Ol]

Ciare have a 10" driver that could be directly combined with a compression tweeter, maybe 2 per channel to get 8 Ohm.
http://www.teleprodottistore.it/shop/ciare/cw250.pdf

[inrank]

i have heard that Hawthorne Audio are releasing a 10" version of the 15" silver iris, i guess a modified 10CX..... sounds promising



when i say party use, i mean they would be more at home than a pair of KEF XQ1's so not ultimatley loud, but enough lol!

[johninCR]

The Hawthorne 10"coax won't be a modded 10CX, but a totally new driver using a different mix of Eminence parts. Cast frame, new type of surround, etc. Probably the only thing the same would the the pathway for the screw in tweeter. Maybe the cone too, since the 10CX got a pretty good reputation with the Adire kit.

If you already have the 10CX rig, then yes free it from the box. If not, you could go with the 12CX, and the higher Q may get you there on it's own (might need a nudge of EQ to fill it out). I understand that there are several new OB specific drivers on the horizon.

[mashaffer]

How wide were you planning on making the baffles? If you are going for a skinny baffle and low Q driversI think you probably ought to figure on some wings even if you only want to go down to 60.

The reason I say that is that the Alpha 10 sims -3dB @ 60Hz in an infinite baffle. In a small baffle it will do much less. A quick run through indicates that in a 15" flat baffle you would be lucky to get -5dB at 100Hz unless I am very much mistaken.

Honestly for a small baffle I think you would be better off with something like this 10"er which should give you a -5dB at 60Hz in the same baffle that gives -5dB at 100Hz. Obviously this driver is not as high quality as the Eminence but since you will no doubt be using a low pass filter on the helper the high frequecy characteristics won't be that important.

Just a thought.

mike

[inrank]

well you are more of an expert than me, so i will go with yours

would'nt that goldwood woofer need to be run activly by the relatively low spl, 87dB ish.?

looking as not to have a seperate bass amp, just to be able to run it of one at the moment....

[mashaffer]

I don't know about expert... just a guy trying to think this through with you. After all this ties in very closely to some designs that I am looking at for HT. As usual $$$ are slowing my implimentation of my ideas. I have to scrape for every dollar toward MDF to finish my TL sub then I can save up the money for some foam insulation boards to make a mockup of my mains and surround concepts. These ideas range form a single GW fullrange to Silver Iris 15" coax and augies.

I welcome others more experienced than I to join in and help us out.

Good point about the efficiency. I suppose that you could use the 4 ohm version if you designed the crossover to account for it or better yet use two of the 8 ohm versions per side. At that price it certainly wouldn't be out of the question. In any case you have about 6dB difference to account for. I suppose an active solution would probably be the best I bet that a passive solution is possible.

Some of the other guys here really are experts and could give you some guidance on crossover designs. Also it is entirely possible that a more efficient driver with adequate Q and fs could be found. The GW was just an example that I could pull out of my hat quickly. Planet10 might be able to find a vintage driver for you that would be more efficient.

In the final analysis even though room is at a premium you might actually get a smaller system for a given low frequency limit using a larger driver. For example a GW 15" MI speaker with a Qts of 1.36 and fs of 41Hz in a 2' wide baffle should be down about 3dB at 50Hz if I am figuring correctly and the Alpha 15 only a whisker behind it while your Alpha 10" can't do that even in an infinite baffle. In a 2' baffle the Alpha 10 would be down more like 12dB I believe. It seems like there are a lot more appropriate drivers in 15" or even 12" than in 10" available.

So what are the size constraints?

mike