Alpha 15s meeting compression driver in two way design

Luigi · « **on:** 29 May 2011, 02:37 am »

I see a few people seem to be messing with compression drivers in waveguides, and mating them to pro woofers, using a crossover of around 1kHz.

I'm wondering whether the Alpha 15s could be mated with the right compression driver, given they are apparently capable of running as high as 2kHz?

Has anyone tried this, with a compression driver and waveguide and a crossover frequency of around 1-1.5kHz?

Would be interested in your reports of the sound quality, imaging and staging and such, given the Econowave gets good reviews.

The reason I ask is I have happened upon a set of Hempcone CO8Vs, as I wanted to hear what compression drivers sound like (I believe this is essentially a Radian coax copy). The crossover Im using is very basic, just a cap and an inductor each side, so they sound a bit shrill but there seems like plenty of promise here, particularly with dynamics. The waveguide is absolutely minimalistic, nothing like the larger waveguides used for controlled dispersion in the Econowave.

Cheers

versus rider · « **Reply #1 on:** 29 May 2011, 09:28 am »

My current set up is, Alpha 15 up to 200Hz , Audax AP170MO from 200Hz - 1500Hz, 400Hz tractrix horn with BMS 4592 mid driver from 1500Hz - 6000Hz and 1000Hz tractrix horn with BMS 4524 driver from 6000Hz - 20KHz. My personal experience is that the Alpha's are only good to 250Hz after that they are working in the vocal range and sound muddy. Having a DEQX digital crossover I can change the crossover points and have three presets to change on the fly, I have tried several combinations and the Alpha's just don't work above that frequency. You will still need something between the Alpha's and the compression driven horn.

Luigi · « **Reply #2 on:** 29 May 2011, 06:38 pm »

Versus Rider
What I thought as well, until I read this about the speaker that Ric is helping to tweak:

"Its a Beyma CD385ND compression driver firing through a 12 inch Geddes waveguide. Xover is at 900 hz at 48db per octave using modified Behringer DCX24/96. Two way, two Alphas running to 900hz. Modified Hurricane amp on bass and Yamamoto 2 watter on CD."

Now he reckons the speaker sounds stonking with all the bracing improvements and whatnot, and no mention of Alpha mud anywhere.
The reason I mention this is that Alpha 15s are meant to be able to run up to around 3000Hz, so I would have thought that 900Hz was at least possible.

Having said that, everyone here reckons the Alphas should be crossed out at around 200Hz. So colour me confusticated.

Ive been using the CO8V with the Radian compression driver over the weekend and really like the sound of the pro tweeter, even though it is running a bit hot and the waveguide is very basic. It makes me realise what Im missing at the top end with the B200s, even with a rear firing tweeter.

JohnR · « **Reply #3 on:** 30 May 2011, 01:05 am »

Hi Luigi, if the CO8V is a coaxial driver, then wouldn't you use the cone driver as a midrange?

Or, you could use a different waveguide/horn and the B200 as a mid.

To cross a 15" to a CD, the Dipole15s would probably be a better choice. I'd be interested to hear how you go if you tried that, actually.

Luigi · « **Reply #4 on:** 30 May 2011, 04:27 am »

Im quite keen to try a proper waveguide with a good CD and use either the B200s or, if they reach up there, the Dipole 15s/Alphas. But at this point it is probably also time to organise an active crossover.
Problem is, everything I have here at present is single ended, and there dont seem to be that many active crossovers with single ended connections. Or perhaps Im mistaken about that?

JohnR · « **Reply #5 on:** 30 May 2011, 05:44 am »

Most are designed for "pro" use. The miniDSP has RCA ins and outs and lower signal levels.

Luigi · « **Reply #6 on:** 30 May 2011, 08:18 am »

You will laugh at this but I bet it doesn't work with a Mac does it? In which case, Im probably screwed on that front, because it looks otherwise like the shiz.

JohnR · « **Reply #7 on:** 30 May 2011, 08:32 am »

Yes, it does

I use a Mac.

Redefy Audio · « **Reply #8 on:** 30 May 2011, 10:13 am »

i found that cross the alpha lower freq yield better result, as the sound became clear and more dynamic.

right now i used them up to 80hz only, as previously it was @200hz.

my coax is BEYMA12CX discontinued model, on w 600mm x h 1050mm baffle.

cheers
henry

Ric Schultz · « **Reply #9 on:** 30 May 2011, 07:30 pm »

If you mount an Alpha on a resonating baffle, do not magnet damp it, do not damp its frame then it sounds like crap. And the higher you use it the crappier the sound. However, if you have at least a 2.25 inch baffle and it is super braced and you brace the magnets and damp the speaker basket then you will hear a whole nuther speaker.

Obviously, if you use a smaller driver or drivers between the woof and the waveguide you will get even more transparency. However, now we are talking 3 way using modified Behringer or whatever and triamping for best sound. Best to cut off the compression driver/dome in the waveguide very sharply.

If you use two seriously done Alphas together then the resonances are cut in half and the transparency goes way up. This is the way I listened to Alphas crossed at 800-1000hz.

So, if you use two Alphas mounted super with a waveguide and crossed at 1000 hz it will blow your mind. We are talking modified Behringer, super cables, super amps, etc. I have heard it!

Even better would be to use 4 Alphas on two separate baffles braced together for the bass and have a another baffle with two 6s for the mids and the waveguide above it. Tri amped using modified Behringer. Your mind would never come back with this system.

You would want to use the 12 inch round Dayton waveguide and cut off the back part with the threads and attach you driver with Amazing Goop and EAR SD40AL so the flare of the waveguide matches your driver. The entire back of the waveguide would need to be covered with EAR SD40AL (stock, it resonates and sounds horrible!!!).
You can line the front of the waveguide with felt and or use foam in it for the Geddes trick.

The $27 Vifa tweeter that has the double chamber on the back can be used with great sound. You HAVE to cut off the back of the chamber and leave the felt in place. This relieves the pressure on the dome and it sounds as good as an Esotar this way (I A/Bed them).

Imagine the speaker in the enclosed link with the bracing and magnet mounting I describe. This is way cool!

http://www.tweakaudio.com/EVS-2/Modding_the_Emerald_Physics_spe.html

holdent · « **Reply #10 on:** 31 May 2011, 02:23 am »

Quote from: JohnR on 30 May 2011, 05:44 am

Most are designed for "pro" use. The miniDSP has RCA ins and outs and lower signal levels.

Actually you can get a miniDSP with balanced ins and outs and higher signal levels as well now (see http://www.minidsp.com/products/minidsp-in-a-box/minidsp-balanced-2x4)

JohnR · « **Reply #11 on:** 31 May 2011, 03:53 am »

Quote from: holdent on 31 May 2011, 02:23 am

Actually you can get a miniDSP with balanced ins and outs and higher signal levels as well now (see http://www.minidsp.com/products/minidsp-in-a-box/minidsp-balanced-2x4)

I know, but he was asking specifically about crossovers with single-ended connections

Luigi · « **Reply #12 on:** 31 May 2011, 07:48 am »

That the MiniDSP works with the Mac, and the small size and cost of the unit - all good, must read up on it, and I note there is plenty of info on making an OB speaker work with this active X-over.

Hadnt noticed your link to hot rodding the Emerald Physics speaker Ric. Thx for that. Lots of good info there.

Im really most impressed with how this Radian CD is sounding, and the concept of not having a hot spot for selfish listening also appeals. Likely as not this represents the horns of a dilemma: OB or horns, or perhaps I can marry the best of both worlds here?!

JohnR · « **Reply #13 on:** 31 May 2011, 08:10 am »

A few folks are using OB bass and crossing to a CD/horn. I'm presently trying to see how far I get with a "pure" OB approach, but I have a pair of CDs on loan and a couple of horn/waveguide options to try with them. Ah... time, if only you could get paid for messing with this stuff

versus rider · « **Reply #14 on:** 31 May 2011, 07:02 pm »

Quote from: holdent on 31 May 2011, 02:23 am

Actually you can get a miniDSP with balanced ins and outs and higher signal levels as well now (see http://www.minidsp.com/products/minidsp-in-a-box/minidsp-balanced-2x4)

Hi Rick, bracing the magnet on my baffles would be a simple job and its already 54mm thick, what kind of damping material would be good for the frame, maybe that sound deadening sticky black stuff thats used inside car body panels perhaps?

Ric Schultz · « **Reply #15 on:** 1 Jun 2011, 01:13 am »

You want to use a constrained layer damping material. EAR SD40AL is the best sounding damping material I have played with. I have not A/Bed it with the cheaper Dynamat Extreme but I bet it is better as the Dynamat has a gooey main layer and the SD40AL is more hard. Gooey tends to sound that way. Percy Audio sells the EAR stuff. I have been using the EAR stuff for years on speaker baskets and various parts with super sonic results. Probably two layers is better.

spkrman57 · « **Reply #16 on:** 25 Jul 2011, 05:02 pm »

A question regarding Eminence apha 15's and open baffle design.

1st off I have a pair of Emerald Physics model cs2's minus 1 horn(available cheaply at PE) and the 220ti drivers.

The biggest item missing from these is the "dsp" unit which provides the bi-amp/EQ funtions for this spkr system and from what I have read is the "glue" that makes everything work correctly!

So in effect I have a pair of baffles and (4) alpha 15's. Has anyone come up with other ways to use this???

Regards, Ron

Ric Schultz · « **Reply #17 on:** 26 Jul 2011, 02:57 am »

Most everything you need to know about modding the CS2 is on my website. The funky pic of a brace at the bottom of the page is seriously needed too.

You just get a Behringer DCX24/96 and any number of people (just ask nice) will send you the program that Emerald Physics used with the original drivers. The stock compression driver is only so so and the waveguide is only good after serious damping, felting and cutting off some of the back where the threads are. You do not want a threaded driver....use a non threaded driver or soft dome tweeter as in the instructions on my website and glue it on the back of the waveguide. The Behringer is OK stock but really needs modding for super sound.

There are pics on my site of a speaker done very well using the modded waveguides and modded Vifa tweeters....he only needs to add the bracing to the panel and back of the magnets for even more super sound.

http://www.tweakaudio.com/EVS-2/Modding_the_Emerald_Physics_spe.html

JohnR · « **Reply #18 on:** 26 Jul 2011, 03:03 am »

Quote from: Ric Schultz on 26 Jul 2011, 02:57 am

You just get a Behringer DCX24/96 and any number of people (just ask nice) will send you the program that Emerald Physics used with the original drivers.

Is that legal? Isn't that their IP?

Ric Schultz · « **Reply #19 on:** 26 Jul 2011, 03:09 am »

Who is getting hurt by sharing software on a speaker no longer being manufactured? All he is doing is equalizing the drivers....anyone with a brain can do the same thing with a Behringer. Just easier to have a place to start from.

There is only one law worth abiding by......that is the law of LOVE. If it hurts no one....it is probably a groovy thing. If it hurts one person....then maybe you should think before acting.