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Celestion Axi2050 2" compression driver


atltx
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I have been looking for something that can minimize crossover complexity for my first speaker build.  It has to be a 2 way.  There are some good compression drivers that go down to 500hz and maybe a little lower.  The TAD TD-4002 is too expensive to play with.  The Celestion Axi2050 can hit 225 to 300hz with a little harmonic distortion for a third of the price.

I don't know where I will find a K402 horn set.  Patience will hopefully pay off.  My Aurasound NS18's are sitting a few feet away; they will take care of the bottom end.  Patience worked while looking for them.  I've seen a few mentions on this forum for the K402's.  Any chance somebody can help me find a set?

I'm thinking this setup will do better than the JBL M2 system I have wanted.  I'll try an Acoustic Elegance bottom end as well.

I plan on learning the hard way.  

Reference:

https://community.klipsch.com/index.php?/topic/199267-celestion-axi2050-2-compression-driver-on-k-402-horn-and-jubilee-bass-bin/

Sorry Ricci...just noticed you already did what I finally discovered.  Maybe that is a good thing.  Lol.

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If you have a lot of money you can purchase the K402 from Klipsch as a cinema replacement part with a driver attached.  The K402 isn't actually that fancy a horn though its basically a huge conical horn with a mouth flare.  A dual slope conic that is typically used in unity horn designs of the same size will approximate its behavior.  This a spreadsheet that can design a horn for you:

http://www.libinst.com/SynergyCalc/Synergy Calc V5.pdf

This person built a more complex replica incorporating the mouth flare:

https://www.stereonet.com/forums/topic/232459-klipsch-k402-replica-build/

I've been designing mid-range horns recently and would caution though that conic horns like the K402 do not provide good loading to throat mounted compression drivers low in frequency compared to there size.  This may mean that it might not sound nice crossing at 300Hz, although the AXI2050 has huge surface area compared to a typical comp and may be OK.   

 

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Yes I've been running these on K-402's for a couple of years. I have a ton of measurements that I planned to post but never got around to. Eventually. 

Long story short...None of the CD's really want to be playing down that low. They may claim 500Hz but even on a very large horn that loads decently they get nasty with any real volume. The 2050's are better than any others I'm aware of. I settled on a 370Hz Xo with mine. The distortion rises precipitously below 350Hz. They may be fine down to 300Hz in a home with 0.25 volt drive levels, but for any real use with loud playback I'd recommend no lower than 370Hz with a 3rd order filter and that's on a BIG horn like a 402 or a 2360A. For work in a pro setting in a huge venue I'd consider 500Hz the minimum with 600Hz being better/safer.

None of the other CD's on the market (Except for some of the exotic dual diaphragm mid units) want anything to do with that low of a crossover in a pro use scenario, no matter what the spec sheet says. If your use is at home with flea powered amps and much more subdued playback levels you can get away with a much lower Xo. 

The Axi2050 provides roughly a half octave better low end extension and lower distortion when driven that low than most 4" vc 2" cd's. The top end is decent but they weren't able to totally defeat physics. Smaller, lighter diaphragm CD's will have better sensitivity, distortion and output >10kHz. The 2050 sounds fine up there but it does give up something. That's the tradeoff. I'm far more concerned with SQ in the 400-10Khz area than I am with >10kHz so it works for me. Sounds killer in the midrange. 

I put 22.5 volts through them during distortion testing. Wore ear plugs and shooting muffs. I am not in a hurry to do that again. It's weird when you can sense/feel the pressure from treble!

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I do like the 402 a lot. They aren't cheap if buying new. Mine were 2nd hand and have some wear and tear. Still expensive. Think it was about $1200 for the pair after shipping from Cali. Doesn't bother me because they are in an ugly warehouse room anyway. Sounds better to me than the 2360A's. The 2360A's do load the low end better / deeper.

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Hi @Ricci have you tried any horns with exponential throat sections with these mid-range drivers? my understanding is that any horn which doesn't have collapsing HF directivity (conic or OS) will have poor loading at low frequency which (I hope) is what makes them sound bad when run low.  I am planning a horn that is used in PA down to 400Hz but it only needs to get to 4kHz so I am basically designing a CE horn (using M200 drivers):

http://www.xlrtechs.com/dbkeele.com/PDF/Keele (1975-05 AES Preprint) - Whats So Sacred Exp Horns.pdf

There are some nice loading graphs on page two of this:

https://www.grc.com/acoustics/An-Introduction-to-Horn-Theory.pdf

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I've not...I will say that the 2360A goes deeper than the K402 in practice. It legit seems to be able to provide loading / gain down to 170 or 180Hz. It needs an 8" mid shoehorned onto it really, but then the throat distortion is going to get boosted. 

The K-402 technically loads to a very low frequency too but it doesn't provide much useful gain at those deep freq's. 

The horn does play a big role. With that said. Even on the giant 2360A the Axi2050 still runs out of gas due to diaphragm displacement limitations near 300Hz. This isn't really seen until absurd output levels with more than 10 volts applied = REAL LOUD, so technically you could get away with a 300Hz Xo on that horn in most cases. Still it cleans up considerably just crossing at 400Hz on that horn and keeping the diaphragm excursion under control. Moral of the story is even after the best sims and thought put into it, test the combo and see what you've actually got. 

Note: The Axi2050 is quite durable. 🤪

I do wonder how good the Celestion horn for these are, but I'm not dropping that amount of money to find out. The B&C horn for the DCX462 / DCX50 also is interesting. 

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Thanks for the link to those instructions for the horn spreadsheet and project build.  That was some very good reading.  I may have blinked 3 times while going through it all.  The info will be put to use eventually. Did some googling for saws and other tools to make it happen.  My metabo gear won't cut it. Might just take some nausea medicine while saving up for the new components and skip the work for now.

The new Jubilee is the reason why I chose the driver.  Hope, Arkansas is an hour away from me.  My local Klipsch dealer has some old stuff that is very interesting.  I've only been able to find new K402's as of today.  $2500 for paired horns, drivers and stands.  No bare lens option without serial numbers from a pair of Jubilee's. Big Red Horn (black) from Celestion as a pair is about the same price.  Used for half price will be hard to find I'm guessing.

Flea power for the horns is the plan for home use.  First Watt F7/8 looks nice.  Bottlehead too.  A headphone amp maybe to not spend a lot of money?  I really do need less than a watt.  370 to 400hz cutoff will be tried after the appreciated recommendation.

Outdoors?  Whatever doesn't make me deaf.  600hz and up.

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  • 2 weeks later...

Some things happen for a reason I guess.  Lean-business.co.uk has sold out of the handmade horn.  Definitely need to relax my mind with a challenge and make the best use of my dollar.

I'm about to ask for a lot of help.  Can somebody please post a list of recommended equipment needed to make horns.  Example: What type of table saw works best?  What other tools would be a best purchase?  

I'm pretty good with fixing stuff and will figure this out.  Not afraid to try.

Thank you

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3 hours ago, atltx said:

Some things happen for a reason I guess.  Lean-business.co.uk has sold out of the handmade horn.  Definitely need to relax my mind with a challenge and make the best use of my dollar.

I'm about to ask for a lot of help.  Can somebody please post a list of recommended equipment needed to make horns.  Example: What type of table saw works best?  What other tools would be a best purchase?  

I'm pretty good with fixing stuff and will figure this out.  Not afraid to try.

Thank you

Tbh I'd personally buy a large enough 3D printer. I have all kinds of equipment, which includes a CNC router, but even then, making horns is something I'd find cumbersome to do. Doing it on the CNC would require doing it in something like 1" slices. Doing it by hand with something like a large Dremel... inaccurate and really tideous work...

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I've been looking at 3d printers for a few hours.  Large format has come a long way since I did any research.  You can print in copper these days too. 

Need to figure out if either a tractor with cab and attachments are really what I want or if making would keep me satisfied.  I miss Tinkermill in Colorado.  They would literally teach the know how and help you build a rocket.  Didn't get to sink my teeth in after joining.

Will keep researching.  

 

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