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Celestion Axi2050 2" compression driver on K-402 horn and Jubilee bass bin


Chris A

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On 3/30/2021 at 7:41 AM, mikld said:

I'm curious if you've found the lacks of high frequency output of the EQ'd Celestion Axi-2050 is audible compared to the Tad-4002 or the BMS 4592ND?


As far as my listening trials over the past few weeks, I've not heard a driver that can compete as well with the TAD TD-4002 as the Axi2050.  It's very close--close enough that it has taken weeks of listening to hear the differences (...if any).  I'm going to hang on to my TD-4002s, but if I was using Axi2050s instead, I'd be fully satisfied.  That's how close they are to one another.  The TADs cost 50% more (new)...12 years ago.

 

The BMS 4592ND (dual diaphragm) is also very close, but the Axi2050 has an extremely smooth response all the way up to 20 kHz using the PEQs I posted above, while the BMS 4592ND has very small crossover disturbance (barely audible) at ~6 kHz.  I believe that the BMS 4592ND has a very slight edge above 6 kHz in my subjective listening, but this difference is extremely minute.  It may be just the polar coverage that is different above 6 kHz. Looking at the time-based spectrogram response from 1 kHz on up to 20 kHz, the Axi2050 is quite smooth and well controlled, and the phase response matches that of the TAD TD-4002/K-402.

 

I have yet to test the polar coverage of the Axi2050 on a K-402 outside (i.e., semi-anechoically) which will tell the story of the highs above 6-8 kHz.  On-axis, the Axi2050 was EQed flat to 20 kHz, so there are no issues in that area, and the time-based REW spectrogram shows approximately equal decay response.  The 4002's SPL response looks a little bit smoother.

 

Chris

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25 minutes ago, Chris A said:

the Axi2050 has an extremely smooth response all the way up to 20 kHz using the PEQs I posted

 

Even though I already had my Axi2050 drivers playing music and sounding wonderful, I appreciate all the research you perform and share with us on the forum.

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13 hours ago, BeFuddledinMn said:

I’m very impressed by Roy Delgado’s work on furthering Paul’s legacy on the entire heritage line. A real renaissance.

Klipsch has done very well of late.  The refresh of the Heritage line + the Forte has apparently been extremely good for sales and has reset the relationship with hi-fi mags (or at least the YouTube hi-fi talking heads) which have largely taken notice.  "Fun" is the catchphrase, and I think the "little direct-radiating loudspeaker flat SPL on axis only" crowd have begun to take some notice (or at least has heard rumblings coming their way).  It's actually been incremental improvements in design--nothing really radically different, with the possible exception of the new Jubilee being marketed as the top-of-the-line loudspeaker for Klipsch, with an internally ported bass bin--which no one here has apparently heard yet, nor have there been any measurements presented. 

 

I can say that the Celestion Axi2050 "axiperiodic" two-inch throat compression driver is a big step up from the K-691 (itself a phase-plug-modified B&C DE75 driver) of the present stock K-402-HF/KPT-KHJ-LF Jubilee.  The dialed-in Axi2050 itself sounds pretty much like the TAD TD-4002s that I've listened to for the past dozen years or so.

 

I can say that most of the hype that other "high end" loudspeaker manufacturers have placed on their own (overpriced) flagship models will be surprised when they actually hear the new Jubilees--which will likely blow them away at any price (assuming all the bells and whistles are tuned-in with the announced DSP box).  I kid you not.

 

Chris

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Spending lots of time trying different schemes of EQ with the system.

 

AND yes, I am using the K402s - I continue to call them 401s for some idiotic reason, thanks for the correction, Chris A.

 

My last post about using the high shelf filter has been superseded by using 10 kHz with no EQ as my reference point.

 

I figure with this I am removing all of the acoustic transformation and making the speaker essentially a WAVEGUIDE - I am using about 6 dB of boost - 20 kHz - Q a bit over 1.0..

 

I have found those xilica graphic EQ filters to be useful.  This is in conjunction with ganging the two channels of the 2040 so that one input channel is only for the Celestions and the other for the woofers and subwoofers.  Being able to adjust both Crites and RYTHMIKs with the input filters is very handy.  I do miss being able to do the same thing between Crites and Celestion but it just takes more work to get the crossover region right.

 

This allows smaller (in cut or boost) filters all around - I am throwing away almost 20 dB of gain at 1kHz and that can result in dips that require even more filters.  I have found using all of these together allows a flatter response without too much of the "arguments" I try to avoid.

 

On the woofers using the graphic filters one can do a really thorough job of removing unwanted output from the woofers and not adversely affect the response at the crossover point which for me is nominally 500 Hz.  I start at -30 dB at 20 kHz, 16 kHz, 10 kHz and 8 kHz - I then less the cut as I proceed down the range. !.25kHz is a big cut since that is where the big peak exists.  

 

I find if I try to go too low with CELESTIONS, just as Chris A warned, things get dicey.  The distortion, as measured by REW, is MUCH greater at the frequencies I am trying to squeeze out of the CELESTIONs than with the Crites woofers - so the key is to preserve the response with the woofers and make use of their lowered measured distortion.

 

With the woofers I am throwing away almost as much level. Again I have found the most pleasing sound is with the reference level being at 100 Hz with the woofers.

 

A nice smooth downward slope from 20 Hz to 20kHz makes for good sound which I feel sure is the case for everyone here,.

 

So the shelving filtrs are a dead end but the graphic filters are a godsend.  Do not be afraid of them.  It does take some time to get used to how they interreact with each other but one can see, before the advent of PEQ these things could do a good job.  As long as the job is for small changes.  I use the PEQ for the big filters and then use as much of the graphic filters as can be utilized.  Sometimes one simply has no choice but to use the PEQ filters, as if that is a bad thing!

 

Even with a ten watts amplifier I do not hear a loss in dynamics - if anything it is otherwise - gets plenty loud for me and that is 100 dB for really raucous recordings (not steady of course).  Any louder than that and my room is distorting more than the speakers.

 

I continue to be amazed at how BEAUTIFUL these things sound - that is the system of K402 and CELESTION with the Crites woofers.  I still must say there is no comparison to what is possible with the addition of two RYTHMIK woofers per channel and trying to let the speakers play as two ways.  No comparison in distortion level and dynamics. If you EQ the MEH to play as a two way it is just not anywhere near as good.  This could well be because of my room size and dimensions.  Even though the things measure fairly flat in the mid bass at one to two meters they do not sound that way at the chair another couple of meters away.  there is a big dip around 115 hz.

 

The effortless bass from four of the RYTHMIKs is something to hear.  The bass simply appears and then dies away.  No thump - no LISTEN TO THAT BASS effect.  Mr. Geddes is right: multiple woofers scattered about the room is better.

 

I have found a good compromise with getting the MEH and the RYTHMIKs to work together in this range.  The RYTHMIKs measure extremely low distortion at 125 hx - of course these are REW numbers and I am not sure how accurate they are - I use them relatively.  The RYTHMIKs and the MEH are sharing the load up to about 130 Hz.

 

The reticulated foam surround on the K402 is simply a three inches sheet of foam with a hole cut out that is  smaller than the mouth - about six inches in width and height,  I see no effect on the woofers response and and a slight smoothing of the compression driver.  One hears much more than one sees with this addition.  II cannot remember the outside dimensions of the sheet.  I will measure it.

 

Same with the scrim of long fiber wool in front of the Celestion.  A slight loss at 20 kHz but an actual rise in response around 8 kHz.  Using two sided tape to hold it close to the front of the Celestion.  It is immediately noticeable as a reduction in something!  Far more relaxing.  I tried it both ways over and over again and it is always an improvement when in place.   Looks funny but then how can one be a serious audiophile kook without that!

 

I will take some photos.

 

Another thing I have found to be useful - a 2 x 4 foot sheet of rock wool on top of each speaker - not night and day but a refinement.

 

There is so much goodness in this arrangement with these drivers.  One can sit back and be astonished that such sound is even possible in the home.

 

Two channel audio has much to offer.

 

One last thing - with these speakers correct polarity has never been so easily heard.  Even though there are times when I think it is good but I figure I should switch it just to be sure only to be very pleasantly surprised it was not and there is this improvement in spaciousness and image along with the all important dynamics.

 

Using the two xilicas as my control center makes polarity change easy even though with the two input channels ganged and using one for each channel I have to click four buttons and access each one for the respective channel.  For some a pain in the rear but I think the trouble is worth it.

 

I wonder with multi channel systems if correct polarity is not quite as noticeable?  I will never know.  I figure I am much too lazy for more than two channels!

 

As usual I write long letters.

 

Take care,

 

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1 hour ago, rickmcinnis said:

I continue to be amazed at how BEAUTIFUL these things sound - that is the system of K402 and CELESTION with the Crites woofers.

I'm glad you're pleased.

 

Chris

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17 hours ago, rickmcinnis said:

The reticulated foam surround on the K402 is simply a three inches sheet of foam with a hole cut out that is  smaller than the mouth - about six inches in width and height,  I see no effect on the woofers response and and a slight smoothing of the compression driver.  One hears much more than one sees with this addition.  II cannot remember the outside dimensions of the sheet.  I will measure it.

 

Same with the scrim of long fiber wool in front of the Celestion.  A slight loss at 20 kHz but an actual rise in response around 8 kHz.  Using two sided tape to hold it close to the front of the Celestion.  It is immediately noticeable as a reduction in something!  Far more relaxing.  I tried it both ways over and over again and it is always an improvement when in place.   Looks funny but then how can one be a serious audiophile kook without that!

 

I will take some photos.

 

Another thing I have found to be useful - a 2 x 4 foot sheet of rock wool on top of each speaker - not night and day but a refinement.

 

 

Sounds like you are getting some really killer results.  Congratulations! 

 

I would love to see some photos of what you are doing with the foam, fiber wool and rock wool.  Post some pics when you can.

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Attached is a photograph of the right channel - the reticulated foam is two inches in depth not three inches.

 

A reason to consider using two equalizers  - of course I would recommend the xilica that I bought upon the recommendation of Chris A:  (seeing Danley used them made it even more an obvious choice)

 

When ganged together and the mixer set for one channel for the Celestion and the other for the Crites you have many more opportunities to make the response flatter but one thing I discovered is that one can completey remove the spike, that occurs in my case around 1200 Hz, using the graphic EQ.

 

Starting at 20 KHz and working your way down - -30 dB all the way down to about 3.15kHz. - I am writing from memory - you make make it go away entirely without as much effect on the top end response of the Crites.  It is almost like magic.  Of course, there is some loss and that is useful just not as much as when I used a PEQ set at the center frequency of the spike plus you get rid of all extraneous information above there.  Since the subs share this channel is assists with those, also.  I intend to post a screenshot of the response tomorrow.  You will see the spike is not minimized it is removed.

 

Same thing is useful for the tweeter in removing low frequencies.  One does have to tailor these, of course.  It would have taken four PEQs to do what you can with these and thus are able to save those for more important tasks.  There is something about the presentation of a system that is dual mono.  

 

So for the rabid and determined I think there is no question one should get a xilica for each channel and gang the inputs.

 

Picture is of a speaker and house still being finalized.  I have had those ROOM TUNES for decades and they make a big difference in front of those windows.  Michael Green was a very interesting fellow.  Does anyone know if he is still involved in audio?

 

The pieces of cloth seen hanging down between the cabinet and the foam is a thick wool damask - what I had to use at the time.  The wool alone made a nice improvement in the sound and the two together better still.  The intention is for all of this to look more "all of a piece" one of these days.

 

You know what is said about good intentions ...

 

Right Channel.jpg

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@rickmcinnis, just to super simplify things, looking at you pic.  You have a 402, mounted vertically, 2 Crites woofers mounted on the horn sides, I see the woofer inlet holes, as @Chris A did.  With a “built in” Rythmik sub below? I might have missed it, but how low does the MEH go w/o the sub? 
Im wondering if the vertical orientation is creating ceiling reflection or horizontal coverage problems? (As opposed to horizontal orientation?) 

thanks, Ted

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  • 2 weeks later...
On 4/26/2021 at 1:49 PM, VDS said:

I'm wondering if the vertical orientation is creating ceiling reflection or horizontal coverage problems? (As opposed to horizontal orientation?)

Horizontal horn orientation is preferred, but they can be used vertically without any issues since they are point source loudspeakers.  Floor and ceiling bounce are the major issues with vertical orientation, and if your ceiling isn't like ~10 feet (3 metres), that ceiling/floor bounce is going to be accentuated in vertical orientation.

 

On 4/26/2021 at 1:49 PM, VDS said:

I might have missed it, but how low does the MEH go w/o the sub?

They will go very low--but with PEQ boost (just like almost all direct radiating subwoofers are set up to reach the lowest frequencies).  In general, they will tend to roll off below ~45-50 Hz if EQ boost is not used.  I think that @rickmcinnis indicated that point was close to his crossover frequency (...or was it higher frequency...?).  It's usually a juggle to match room dimensions and relative dimensions (i.e., room modes) and where the loudspeaker is placed.  In my room, I place the MEH in the center, and since I don't have a sub in the center of the room,  extending the bass response of the K-402-MEH prototype adds greatly to the low bass coverage (like "filling up" the room modes at the nodes and anti-nodes characteristic of the room's dimensions). 

 

Chris

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@rickmcinnis

 

On 4/22/2021 at 10:08 PM, rickmcinnis said:

Same with the scrim of long fiber wool in front of the Celestion.  A slight loss at 20 kHz but an actual rise in response around 8 kHz.  Using two sided tape to hold it close to the front of the Celestion.  It is immediately noticeable as a reduction in something!  Far more relaxing.  I tried it both ways over and over again and it is always an improvement when in place.   Looks funny but then how can one be a serious audiophile kook without that!

 

Is that a similar idea as with Geddes foam-plug of reticulated foam in front of the throat in his Summas/OS high-frequency-horn?

 

As I have understood it, Geddes foam-plug is there, to prevent "back-reflections" from the horn-mouth to re-enter the horn and be emitted out. Some sort of absorption of reflections? Maybe it´s something related to his HOM´s!?

 

Well, I´m not sure my explanation is right. But an interesting thing to explore if it has "relaxing" effect, and could be an improvement!?

 

Steffen

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On 3/17/2021 at 4:07 PM, Chris A said:

I read somewhere on diyAudio that some guy was using a pair of Axi2050s without horns--like they were full-range loudspeakers.  I assume he flattened the response a bit using some form of EQ somewhere upstream...but it is an interesting notion.

 

I bet they sound like really good table radios.

 

Chris

That'd be me 😃

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Hi!
 

I only did that for the experience, I have several horns to audition and some horns to build yet. Right now I am trying to sort a new (finale) amp. I was just so impressed of the Axi's dynamic ability with or without horn. A waveguide doesnt load much, if at all, so its not that impressive I guess considering for some, its old news....the dynamic ability of compression drivers that is.

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If you can find the larger SEOS 30 or (much better) K-402 horns--after dialing in the EQ to compensate for the fact that these are controlled directivity horns--I think you'll be so impressed that you'll never be able to go back to anything smaller.  The Axi2050 on a K-402 easily crosses at 225 Hz without boosting EQ (except above 15 kHz), and pretty much matches my TAD TD-4002s that I've listened to for 12 years now (on K-402 horns). 

 

We have a fairly large contingent of folks here that have heard or own K-402s, and have mostly imprinted on them as their acoustic reference baseline.  You should hear them.  They pretty much blow away the smaller K-510s that pioneered the originating horn profile.

 

The Axi2050 on a K-402 horn with a newly designed folded corner horn bass bin is the basis of the new and upcoming Klipsch Jubilee, the flagship model for KGI:

 

 

Chris

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You show me a legitimately priced K402 horn and I'll buy it... I haven't seen one for sale in two years of searching  for various horns...

 

so far I have acquired; jbl 2380a, jbl2386, 350hz e-tractrix, and recently a pair ev hp420's

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2 hours ago, LTusler said:

In case anyone is interested, the 2050's are back in stock at Parts Express.  My pair arrives Wednesday!

Just on a cautionary note. Do you think the 2050's that Klipsch buys (and perhaps modifies) are same quality as the ones  that Parts Express buys? Do you think that Klipsch might require certain modifications on the 2050's when they buy them? Something to consider. 

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18 minutes ago, PrestonTom said:

Just on a cautionary note. Do you think the 2050's that Klipsch buys (and perhaps modifies) are same quality as the ones  that Parts Express buys? Do you think that Klipsch might require certain modifications on the 2050's when they buy them? Something to consider. 

 

Don't know if there are any internal differences from a stock 2050 for the new Heritage Jubilee.  However, there is an external acoustic horn lens being used with it.  (Thanks @Chris A for clarifying that the phase plug terminology used in the video is incorrect.)

 

 

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