hooked on ob sound... what to build first?

matevana · « **Reply #40 on:** 23 Mar 2015, 10:09 pm »

Yes. I think the 1 inch offset is very smart for the exact reason you mentioned.

Thanks Martin.

wendelltate · « **Reply #41 on:** 7 Apr 2015, 02:14 pm »

So...I was studying over my friend's OB speakers which are incredible. They have 2 Eminence 15" on each side and one of them has a compression driver screwed into it. They are passively crossed at 800.

How do you guys think it would work to use to Alpha 15s on the bottom of each and these Eminence 12" with a screw in compression driver on top?
http://www.parts-express.com/eminence-beta-12cx-12-coaxial-driver--290-504

Eminence does not make the 15" coax anymore as far as I can tell...

Would it be possible to use the basic $100 minidsp with this setup ? Or would it be better to experiment with passive crossovers?

Or would it not work at all?
Thx

bladesmith · « **Reply #42 on:** 7 Apr 2015, 04:54 pm »

I don't see why not, people are having a lot of luck with those eminence 15"s Alpha's in simple flat OB speaker set ups.
Go 24" x 24" baffle on the lower woofer, it should sound good.

wendelltate · « **Reply #43 on:** 7 Apr 2015, 06:05 pm »

Quote from: bladesmith on 7 Apr 2015, 04:54 pm

I don't see why not, people are having a lot of luck with those eminence 15"s Alpha's in simple flat OB speaker set ups.
Go 24" x 24" baffle on the lower woofer, it should sound good.

Could the Behringer CX3400 be used to play with the crossover? Is this a good option for active crossover experimentation?

MJK · « **Reply #44 on:** 8 Apr 2015, 12:18 am »

Quote from: wendelltate on 7 Apr 2015, 06:05 pm

Could the Behringer CX3400 be used to play with the crossover? Is this a good option for active crossover experimentation?

I don't think so. You are limited to 24 dB/octave. All the dipole designs I have built have used 6 dB or 12 dB/octave filters. I would recommend one of the minidsp crossovers, the Behringer DDCX2496 crossover, or the dBx Driverack crossover. These three are much more poweful and will allow you to have a lot more adjustability.

Tyson · « **Reply #45 on:** 8 Apr 2015, 02:34 am »

The miniDSP 4x10HD has an incredibly well designed user interface. Just load it to your computer, connect a USB cable, and you are able to make adjustments in real time. The ability to do up to a 4 way speaker, act as a preamp with volume control and a hirez DAC all in one are a huge plus, IMO.

bladesmith · « **Reply #46 on:** 8 Apr 2015, 03:05 am »

Quote from: wendelltate on 7 Apr 2015, 02:14 pm

So...I was studying over my friend's OB speakers which are incredible. They have 2 Eminence 15" on each side and one of them has a compression driver screwed into it. They are passively crossed at 800.

How do you guys think it would work to use to Alpha 15s on the bottom of each and these Eminence 12" with a screw in compression driver on top?
http://www.parts-express.com/eminence-beta-12cx-12-coaxial-driver--290-504

Eminence does not make the 15" coax anymore as far as I can tell...

Would it be possible to use the basic $100 minidsp with this setup ? Or would it be better to experiment with passive crossovers?

Or would it not work at all?
Thx

If you can afford it, try the delta 15lfa's on the bottom. They work great in OB design.

http://www.parts-express.com/eminence-delta-15lfa-15-low-frequency-driver--290-417

V....

bentconvert · « **Reply #47 on:** 9 Apr 2015, 02:26 am »

I've been thinking about my first OB build and was wondering if anyone has experience with the GRS 12SW-4 [/url]http://www.parts-express.com/grs-12sw-4-12-poly-cone-subwoofer-4-ohm--292-484[/url]. From reading about OB these seem like a good possibility for powered bass. Qts=.98, Fs=29.6, and Xmax 8.5mm.
Was thinking about 2/side in H-frame or on flat baffle for bass and experimenting with Jordan J92s or Pioneer PAX-20 coax that I already own for the top.
Am I missing something?

Thanks,
Steve

Morfeus · « **Reply #48 on:** 9 Apr 2015, 06:00 am »

Quote from: wendelltate on 7 Apr 2015, 02:14 pm

How do you guys think it would work to use to Alpha 15s on the bottom of each and these Eminence 12" with a screw in compression driver on top?
http://www.parts-express.com/eminence-beta-12cx-12-coaxial-driver--290-504

I am just building an OB with a H-frame with one Alpha 15 on the bottom. OB Driver is the 12LTA. I cut out the dust cap an fixed a cheap but very good car tweeter with neodymium magnets instead of the dustcup. Works incredibly well.

Car tweeter is a Lanzar: http://cartweetersx.blogspot.de/2012/08/lanzar-dct-1-inch-silk-dome-neodymium.html

wendelltate · « **Reply #49 on:** 9 Apr 2015, 12:13 pm »

Quote from: Morfeus on 9 Apr 2015, 06:00 am

I am just building an OB with a H-frame with one Alpha 15 on the bottom. OB Driver is the 12LTA. I cut out the dust cap an fixed a cheap but very good car tweeter with neodymium magnets instead of the dustcup. Works incredibly well.

Car tweeter is a Lanzar: http://cartweetersx.blogspot.de/2012/08/lanzar-dct-1-inch-silk-dome-neodymium.html

That sounds very similar to what I am thinking about. I already have the Selenium 220i compression drivers.

wendelltate · « **Reply #50 on:** 9 Apr 2015, 12:25 pm »

Quote from: Tyson on 8 Apr 2015, 02:34 am

The miniDSP 4x10HD has an incredibly well designed user interface. Just load it to your computer, connect a USB cable, and you are able to make adjustments in real time. The ability to do up to a 4 way speaker, act as a preamp with volume control and a hirez DAC all in one are a huge plus, IMO.

My problem is that I just don't have that much cash. I am trying to see if I have a friend nearby who has a DSP that I can borrow for to figure out the crossover. I would prefer to ultimately have these speakers as passive instead of active.

Morfeus · « **Reply #51 on:** 9 Apr 2015, 03:13 pm »

Mine are passive too. 6dB seems to work very well. But I simulated many hours with Martins Matcad worksheets. I prefer to solve as many things mechanically as I can. If you shift around the drivers on the baffle you can see easily what will happen. That's why passive and 6dB was possible on my builds so far.

brad944911 · « **Reply #52 on:** 9 Apr 2015, 03:22 pm »

Wendell, Morfeus,
I had the same mindset with mine...passive all the way. It is nice to see a well executed crossover board on a great sounding speaker IMO. I had to change paths, though. The crossover points I used just didn't match my room or my ears and I didn't want a stack of components lying around. I primarily use Crown CDI amps with DSP on board and what a difference it makes! Everything is tweakable!! I also use the Behringer iNuke DSP amps. Not quite as polished as a Crown, but nearly as versatile...and 1/4 the price. I got mine for $199 from Sam Ash...they will NEED a fan upgrade though.
Just my experience, bud and I am in no way saying that mine compare with any of the uber high end stuff, but I ain't rich. I just wanted good sound and I got it w/ open baffle, good avice from this circle and some fiddling around with EQ, x-over and mics.
Best of luck,
Brad

Morfeus · « **Reply #53 on:** 9 Apr 2015, 03:53 pm »

Nothing wrong with active, Brad. Much easier too, if you don't have lots of resistors, capacitors and inductors lying around. But I like the tweaking this way and through Martins excellent worksheets, the simulations are very close to reality.

wendelltate · « **Reply #54 on:** 10 Apr 2015, 01:58 pm »

so...what would be a decent entry level DSP? I would be fine with the miniDSP but the entry level one only does 2 channel. I know less than nothing about this but would love to learn. I can't spend the $300 plus on the Behringer. Are there any other options?
Thanks

MJK · « **Reply #55 on:** 10 Apr 2015, 02:24 pm »

Quote from: wendelltate on 9 Apr 2015, 12:25 pm

My problem is that I just don't have that much cash. I am trying to see if I have a friend nearby who has a DSP that I can borrow for to figure out the crossover. I would prefer to ultimately have these speakers as passive instead of active.

See Post #30, the work is done all you need to do is gather parts and build.

I see you want to use DSP and a compression driver (this better be a 3 or 4 way system), you also want to cut corners on cost, and it seems to be your first attempt at an OB design without doing the design work. In my opinion you are about to mess up and waste money. Build a proven design first and learn.

bladesmith · « **Reply #56 on:** 10 Apr 2015, 06:04 pm »

Quote from: wendelltate on 7 Apr 2015, 02:14 pm

How do you guys think it would work to use to Alpha 15s on the bottom of each and these Eminence 12" with a screw in compression driver on top?
http://www.parts-express.com/eminence-beta-12cx-12-coaxial-driver--290-504
Thx

If your budget can afford it, I would go with the 15" Alpha A eminence on the bottom with a full range driver on top. Leave the full ranger alone and put a simple passive "low pass" filter on the 15" low range eminence driver. That's simple and easy and you can use a simple flat baffle.

"Pureaudioproject" does it and it sounds very nice ( pureaudioproject.com ). A long with hundreds of other people, Pureaudio didn't invent it and it is a solid/simple tested design, done over and over. It's not that complicated. Adding a second 15" driver makes it better. But, you must start somewhere.

Good luck...

wendelltate · « **Reply #57 on:** 10 Apr 2015, 06:48 pm »

So...if I were going to use the Eminence Alpha 15 with the Tymphany TC9FD18-08 3-1/2" what inductor or capacitor parts would I need to start with to limit the Alpha?
Thanks

bladesmith · « **Reply #58 on:** 10 Apr 2015, 07:40 pm »

I would low pass the 15" at 200hz., even though the 15" is more sensative, it won't show it as much in a flat open baffle.

But, it's an inexpensive way to start. For a few dollars more, I'd go with this

https://www.madisoundspeakerstore.com/approx-4-fullrange/fostex-fe103en-4-full-range/

http://www.quarter-wave.com/Gallery/Gallery.html

Good luck..

MJK · « **Reply #59 on:** 10 Apr 2015, 07:55 pm »

You are going to struggle mating those two drivers, the Tymphany is not efficient enough. Buy the Fostex FF85WK it is just right for the Alpha 15A.