I had the same thoughts regarding cutoff but more like 2.5K, don't know about the horn but I'm guesing cut off should be the sameish as a 10" diameter wave guide which works down to 2.5k ish:
Red Spade Audio: Waveguide shootout 2 - measurements
Crossing at this point should be ok due to the lack of lobbing due to low centre to centre distance. Not sure if the directivity will match but that is what measurement is for!
The Beta-10CX and APT50 combination was used in the Adire HE10.1 kit with good results. The crossover frequency is about 1.9 khz. The schematic and layout is shown in this review from AudioXpress. http://h-audio.de/lautsprecherdaten/eminence/203dell2119-1.pdf
A better compression driver like the BMS or selenium driver could be a better performer, if you have the measurement equipment and knowledge to design a proper crossover.
However, the horn to cone transition is pretty poor in these model. As you can see in the cutaway that was posted in the design document, it goes from a ~30 degree conical through the pole piece and the short aluminum horn and has an abrupt transition to the cone / former, causing some reflections.
This design was originally used in a Fender product, I believe with a piezo driver as the tweeter and a white plastic horn (under the dustcap).
While still not perfect, something like the B&C 12FCX76 is much better (but also a ton more money).
A better compression driver like the BMS or selenium driver could be a better performer, if you have the measurement equipment and knowledge to design a proper crossover.
However, the horn to cone transition is pretty poor in these model. As you can see in the cutaway that was posted in the design document, it goes from a ~30 degree conical through the pole piece and the short aluminum horn and has an abrupt transition to the cone / former, causing some reflections.
This design was originally used in a Fender product, I believe with a piezo driver as the tweeter and a white plastic horn (under the dustcap).
While still not perfect, something like the B&C 12FCX76 is much better (but also a ton more money).
Actually, it was just and APT50. I feel like I can say that now Adire is no longer in business (I used to work there). It is really hard to sell "just a crossover" and so there had to be the claim of a proprietary driver.
They actually had their own internal crossover solver (based on a genetic type algorithm) that was used on that design, and so a lot of work went into it.
They also did some work on an XBL version of the beta 10CX that actually sounded a lot better (particularly through the midrange even) than the stock unit, but it never made it into production.
They actually had their own internal crossover solver (based on a genetic type algorithm) that was used on that design, and so a lot of work went into it.
They also did some work on an XBL version of the beta 10CX that actually sounded a lot better (particularly through the midrange even) than the stock unit, but it never made it into production.
The original kit was based off of the APT50. That is the one that was reviewed in the article I linked. It really is a nice crossover and would need DSP / PEQ to duplicate in an active setup.
Later they redid the design with another compression driver and renamed it the HE10.1 MkII. It was a little off-the-shelf unit that Adire called the the ACD1. It was sourced through a company called Sound Lab of Chicago, I think. It looked quite similar to a Pyle model, at the time. It was a similar sort of design but used a titanium diaphragm instead of phenolic.
Later they redid the design with another compression driver and renamed it the HE10.1 MkII. It was a little off-the-shelf unit that Adire called the the ACD1. It was sourced through a company called Sound Lab of Chicago, I think. It looked quite similar to a Pyle model, at the time. It was a similar sort of design but used a titanium diaphragm instead of phenolic.
Very important:
Latest APT50 pdf on Eminence site states that "A negative voltage at the red terminal causes a positive pressure at the output of the device". But earlier pdf stated that positive voltage on red terminal causes a positive pressure. I was confused so I contacted Eminence about this issue and they told me that earlier pdf was wrong and that new pdf is right for all APT50.
After reading D'Apolito review for Adire kits I am in doubt if bad sound some people experince with APT50 is due to wrong polarity markings on the driver itself?
Latest APT50 pdf on Eminence site states that "A negative voltage at the red terminal causes a positive pressure at the output of the device". But earlier pdf stated that positive voltage on red terminal causes a positive pressure. I was confused so I contacted Eminence about this issue and they told me that earlier pdf was wrong and that new pdf is right for all APT50.
After reading D'Apolito review for Adire kits I am in doubt if bad sound some people experince with APT50 is due to wrong polarity markings on the driver itself?
Well the APT is now an updated design which I believe has an improved exit angle for mating to the CX10 which might account for the more recent, more positive user reviews. I do think there's better options for use with the CX10 and I suspect compression units with phase plugs will perform better combined with a lower crossover point. Faital Pro has two such 1" drivers with non metal diaphragms whose responses appear to be incredibly smooth!
I have both the beta10cx and the 8cx. As far as I can tell, the horn is the same. It is 1.875" dia, which would be good to about 2300 hz if you go by the wavelength divided by pi.
Driven with a selenium 220ti and no crossover shows it dropping off rapidly below 2Khz, so 2.5K seems like a good xover point.
Driven with a selenium 220ti and no crossover shows it dropping off rapidly below 2Khz, so 2.5K seems like a good xover point.
Probably also an Accidental MLTL?
The Beta 10CX is a driver that I am looking forward to getting and using in a variety of enclosures. Namely, the Karlson K15 and Karlsonator are both great boxes for this driver according to my sims here: http://www.diyaudio.com/forums/full-range/239386-karlsonator-4.html#post3570914
But I noticed that the dimensions being used by the OP make this tower speaker, a potential accidental mass loaded transmission line (MLTL). I actually use the accidental MLTL (AMLTL) to design some nice speakers with great bass extension (beyond what the BR programs predict as the tuning freq). Lengths from 30 in to 60 with the vent located towards the bottom all exhibit this feature. The AMLTL is described here: http://www.diyaudio.com/forums/full-range/231951-accidental-mltl-technique.html
So I think these speakers may actually have deeper bass than you think and should sound nicer than just a bass reflex.
It may sound even better if you stretch it to 48 in tall and make depth 10.5 in to preserve volume but give the TL effect more distance to develop. One thing that can help is to use stuffing in top 2/3rds rather than just lining walls with batting per BR design methods. This will help reduce a lot of high freq peaks and dips from getting out the port.
The Beta 10CX is a driver that I am looking forward to getting and using in a variety of enclosures. Namely, the Karlson K15 and Karlsonator are both great boxes for this driver according to my sims here: http://www.diyaudio.com/forums/full-range/239386-karlsonator-4.html#post3570914
But I noticed that the dimensions being used by the OP make this tower speaker, a potential accidental mass loaded transmission line (MLTL). I actually use the accidental MLTL (AMLTL) to design some nice speakers with great bass extension (beyond what the BR programs predict as the tuning freq). Lengths from 30 in to 60 with the vent located towards the bottom all exhibit this feature. The AMLTL is described here: http://www.diyaudio.com/forums/full-range/231951-accidental-mltl-technique.html
So I think these speakers may actually have deeper bass than you think and should sound nicer than just a bass reflex.
It may sound even better if you stretch it to 48 in tall and make depth 10.5 in to preserve volume but give the TL effect more distance to develop. One thing that can help is to use stuffing in top 2/3rds rather than just lining walls with batting per BR design methods. This will help reduce a lot of high freq peaks and dips from getting out the port.
Beta 10CX in a 45 in tall MLTL tower
Here is a sim of a Beta 10Cx in an optimized MLTL. The design is: 45 in tall, 12 in wide, 11 in deep, 4 in dia x 5.25 in long vent at 6 in from bottom, driver 11 in from top, stuffing in upper 2/3rds of TL.
First plot is frequency response at 1 m, with speaker placed against a wall. Second plot is impedance, and third is cone displacement.
This design seems like it has some nice deep bass. The HF will be handled by the CD and horn (not simulated).
Here is a sim of a Beta 10Cx in an optimized MLTL. The design is: 45 in tall, 12 in wide, 11 in deep, 4 in dia x 5.25 in long vent at 6 in from bottom, driver 11 in from top, stuffing in upper 2/3rds of TL.
First plot is frequency response at 1 m, with speaker placed against a wall. Second plot is impedance, and third is cone displacement.
This design seems like it has some nice deep bass. The HF will be handled by the CD and horn (not simulated).
Attachments
Can you please post a diagram of the crossover you are using including component values? I want to add the crossover and CD horn to my model of the MLTL with the Beta 10cx.
Thanks
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