Jump to content
The Klipsch Audio Community
Sign in to follow this  
mopardave

2way Cornwall?

Recommended Posts

I know i'm a little late to the table on this subject, but has anyone here tried a 2way Cornwall mod?   Maybe a 3way with a different mid horn?  What ever has best sound improvements.

Gonna be reveneering my home built vertical CW's.   Thinking this would be a good time for improving the sound output and would be fun.   I will not be able to remove the motor board for a fresh new look.  When I built them I used liquid nails as well as finish nails to assemble, so I will be stuck with current motor board.  I would be interested in building the mid horn horizontal and in plain with the tweeter, so the replacement mid horn would be have to be as large in width as the current mid horn is long.    This mod must make sonic improvements over the current k57k/k77 combo or there's just no point obviously.     So, anyone ever done this mod with good results?       I know nothing about horns or the terminology, but would appreciate any info on the subject as far as what mid horns to use and what to stay away from..    I'm sure if I perform the mod their are a few guys here that can help with the crossover.          Thanks

 

CW big mid horn 3 way.jpg

CW 2 way.jpg

IMG_0416.JPG

IMG_0415.JPG

  • Like 1

Share this post


Link to post
Share on other sites

Interesting :D  Could you just cut out the motorboard ... say 1 inch from the sides, put strips of wood behind these "edges," and just put a new motorboard in?  

That way you could use Crites' Faital horns and also re-position your woofer.

Or ... maybe use K510 horns. See thread below. Haha ... thinking about this now as I have an extra set of 510's :) 

Any thoughts on crossovers?

 

 

Share this post


Link to post
Share on other sites
3 hours ago, Emile said:

Interesting :D  Could you just cut out the motorboard ... say 1 inch from the sides, put strips of wood behind these "edges," and just put a new motorboard in?  

That way you could use Crites' Faital horns and also re-position your woofer.

Or ... maybe use K510 horns. See thread below. Haha ... thinking about this now as I have an extra set of 510's :) 

Any thoughts on crossovers?

 

 

Thanks for those links guys.  Awesome.   I will have to see what trouble replacing that motor board will be.  I'll figure something and shouldn't be too bad as I plan on veneering the motor board as well.     

  • Like 1

Share this post


Link to post
Share on other sites

Looks like I will be doing some shopping for the faital 140/cs500/k510 horns.  Do you think I would be able to use the eminence kappalite 3015lf woofers claude is going to use in his super CW project or do I need to stick with the Crites woofers?   Just curious to any options I may have if any.

Share this post


Link to post
Share on other sites

I will be attempting this mod this summer, maybe late summer with a veneer job.    Read all I could find on the fastrac and k510 mid horns.   It looks like either of those 2 horns could be mounted vertically with good results if I understood what I read.  I could make that look nice with ease compared to replacing the motor board to center everything up.   Has anyone 

AB'd these 2 way vs 3 way using the k510 or fastrac horns?   I'm curious if the 2 sound any different and trying to decide which way to go with this mod.

    

Share this post


Link to post
Share on other sites

After reading a bunch from the Crites site I think the Cornscala 3way version would be a more interesting build and more info out there about that build as a bunch have been built.

 Still not certain what mid horn/driver combo is best in this build thou.  M2380,PH2380,H4427 or the K510.   So, at this point what is most preferred for the mid horn/driver combo in the Cornscala because at this point i'm totally confused in this arena of mid horn/driver combos?   

 I really like the results of this build.

speaker-2-internet_med cornscala.jpg

Share this post


Link to post
Share on other sites

I understand that k510 is popular in a 2way cornscala, but not so much in a 3way design. It is said it needs EQ'ing as well.  I'm really leaning toward the ALk universals for this build that way I can adjust the mid horn output if needed.   I read a bunch on this subject yesterday and still uncertain on the mid horn/driver combo.  I prefer to mount the horns behind the board so I can get the grills on as well.

Share this post


Link to post
Share on other sites

K510 (sorry for previous fat finger accident of typing K519 it should have been  K510) is used as a tweeter in a number of big Klipsch pro speakers which attests to its wife bandwidth and so its outstanding design. Most all horns require eq this is not a fault of the horn just a fact of life and how they work. The requires eq gives you the response they are capable of and it is not in any way a detraction from their remarkable performance. Two ways sound and perform differently from three ways. You should listen to examples of both and see which you prefer before you decide upon your build. A two way has the benefit of integrating over a shorter physical distance than a three way can so it is better when listening in the near field (less than 14" from the speaker). There is also the fact that a three way has one more section of crossover to have to deal (messing with the sound) with and to listen to. A good two way will require better quality and wider bandwidth drivers compared to a good three way but I believe that a good two way will sound better than a good three way. Finally going large format is a massive jump in reducing distortion. After experiencing large format compression drivers you will find it difficult to go back to small format drives at double the distortion level regardless of your playback level. Just something to consider. You can also consider a BMS two way dual diaphragm compression driver on a single horn a number of members here have used this driver  and can comment. JBL have one but it is more expensive. Good luck with your project.

Share this post


Link to post
Share on other sites

I picked up an old pair of Cornwall cabinets that I used as a base to build a 3-way Cornscala and compared directly to a working Cornwall II.  I was not happy with the former (sounded too bright), so I began a lengthy process of modifying to a 2-way design using various horns/waveguides and active Eq.  This resulted in the need to build a new cabinet, but basically the same footprint and volume as the Cornwall.  I settled on what I think is a very pleasant 2-way design using Crites CW1526C woofers and SEOS 18" waveguides with a BMS 4550 1" HF drivers crossed at 850 Hz.  The active Eq is a pretty much a requirement based on the characteristics of the waveguide and driver combo, but the results are respectable to 20 KHz.

 

Here's an in-room measurement without room correction:

2-way Corn BMS 4550_sm.jpg

Edited by GFelber

Share this post


Link to post
Share on other sites

Hey thanks guys. Some good info here.  Wasn't sure which sounded better 2 or 3way.  Some like the 2 and some like the 3.  The aesthetics of the 3ways are better in my opinion.  I will check out those drivers. It seems most are using Faital or Selenium.   On Crites site I see he sales the motor boards. If I can get mine out I see getting those a good option.  I take a look at those 519 horns too.  Thanks

Share this post


Link to post
Share on other sites

Just in case someone reading this thread might want to know the measurement part of the story, below you will see a plot of group delay distortion (the rate of change of phase vs. frequency), a comparison of a stock 1979 Cornwall (three way) in the green trace vs. a Cornwall bass bin plus ESS Air Motion Transformer-1 (two way) in the gold trace.  Anything above ~2 ms of group delay distortion is audible:

 

2134763204_1979Cornwall(stock)vs.CornwallBassESSAMT-1GroupDelay.thumb.jpg.321b2e1962b661ce3636ce03a96503d8.jpg

 

The thresholds of group delay distortion audibility are shown in the table below:

Blauert and Laws GD Audibility Thresholds.PNG

 

Here is the plot of phase vs. frequency (zoomed all the way out as far as REW can go):

1897133681_1979Cornwall(stock)vs.CornwallBassESSAMT-1phase.thumb.jpg.0f700a9ef0454edfde0a10a9a8616618.jpg

 

I can also plot harmonic distortion, step response, impulse response, etc.  All of the plots show the same sort of performance differences between the passive crossover 1979 Cornwall and the DSP crossover/EQed 1979 Cornwall bass bin + ESS AMT-1 driver on top (both configurations using first order crossover filters). 

 

Chris

Share this post


Link to post
Share on other sites

Below you will see a comparison of the frequency responses of the two configurations:

 

359533065_1979Cornwall(stock)vs.CornwallBassESSAMT-1FreqResp.thumb.jpg.291095dca785e2ee1b731c65041af2a8.jpg

Share this post


Link to post
Share on other sites
4 hours ago, Chris A said:

Below you will see a comparison of the frequency responses of the two configurations:

 

359533065_1979Cornwall(stock)vs.CornwallBassESSAMT-1FreqResp.thumb.jpg.291095dca785e2ee1b731c65041af2a8.jpg

Not very good at reading that last graph, but looks like the 2way has more output, but how does that sound to your ear?  

Share this post


Link to post
Share on other sites

They sound superb.  That's why I wrote about the AMT-1/Cornwall bass bin combination.  There are others on the forum that have also gone this direction.

 

Actually, the two measurements that I posted above were taken about 3 years apart (in the same room, in the same location within the room), so the preamplifier gains were a little different, hence the difference in average SPL for the two measurements. But I wanted to show the difference in smoothness of the frequency response using the DSP crossover.  That smoothness is something that you can also hear--in spades.  Since the 2-way was at a higher SPL, it actually should be reading a little worse than the lower SPL stock Cornwall measurement, but as you can see the smoothness and notable lower values of group delay of the [two-way Cornwall bass bin plus the AMT-1] eclipses the three-way stock Cornwall. 

 

You asked if the two-way versions sounded better.  My plots posted above were a bit better than just a subjective "oh yeah, it sounds better..." reply.  That's why I posted the measurements. The difference is pretty large.  But it depends on what you're going to do on the HF portion. I used an AMT-1, but I've also used a K-510/K-69-A on top.  The AMT-1 is now $170 from ESS (down from $500-$700 each not very long ago).  That makes that driver very affordable.  But there are a lot of other choices to choose from.  Bob Crites has integrated the FaitalPRO horn with a FaitalPRO HF140, which comes out to about to a bit over $700 for two, while the ESS AMT-1 comes out to $340 for two (price includes shipment to the buyer).  The other thing is that the AMT-1 has outstanding transient response--all the way up to 20 kHz.

 

I'm not trying to lay out why you should buy one thing or the other, in reality I'm only trying to point out that there is a lot of potential for sound quality improvement that's available--and at relatively low cost, without resorting to high priced horns/drivers (like the K-510 with an attached driver that you'll want to replace soon).  Right now, there is a dearth of options for good horns (IMHO) that can be avoided using something like an AMT.  Note that there are also downsides to the AMTs:

  1. they don't have much vertical coverage, so you'll need to aim the AMT at your listening position and position them near your sitting head height.
  2. they are dipole radiators (which is actually an advantage in that it will preclude the need for tube electronics to add "magic"...a.k.a., tight reverb, that adds depth to the soundstage) but they really need to be spaced a little distance from the front wall--like a couple of feet--in order to maximize that effect.  This is an issue when considering that the bass bin performs better when touching the front wall, getting quarter-space boundary gain.
  3. I wouldn't try to use AMT-1s in a two-way configuration if you're going to be listening at 100+ dB much of the time, since there is a rise in harmonic distortion below 2 kHz when driven at 100-105+ dB levels at the listening position.  (The way around that is to use the Cornwall's K-600 horn and K-55 driver up to 2 kHz, then cross over to an AMT-1. This is easy to do with a DSP crossover having at least 2 input channels and 6 output channels.)

Chris

Share this post


Link to post
Share on other sites
27 minutes ago, Chris A said:

They sound superb.  That's why I wrote about the AMT-1/Cornwall bass bin combination.  There are others on the forum that have also gone this direction.

 

Actually, the two measurements that I posted above were taken about 3 years apart (in the same room, in the same location within the room), so the preamplifier gains were a little different, hence the difference in average SPL for the two measurements. But I wanted to show the difference in smoothness of the frequency response using the DSP crossover.  That smoothness is something that you can also hear--in spades.  Since the 2-way was at a higher SPL, it actually should be reading a little worse than the lower SPL stock Cornwall measurement, but as you can see the smoothness and notable lower values of group delay of the [two-way Cornwall bass bin plus the AMT-1] eclipses the three-way stock Cornwall. 

 

You asked if the two-way versions sounded better.  My plots posted above were a bit better than just a subjective "oh yeah, it sounds better..." reply.  That's why I posted the measurements. The difference is pretty large.  But it depends on what you're going to do on the HF portion. I used an AMT-1, but I've also used a K-510/K-69-A on top.  The AMT-1 is now $170 from ESS (down from $500-$700 each not very long ago).  That makes that driver very affordable.  But that are a lot of other choices to choose from.  Bob Crites has integrated the FailPRO horn with a FaitalPRO HF140, which comes out to about to a bit over $700 for two, while the ESS AMT-1 comes out to $340 for two (price includes shipment to the buyer).  The other thing is that the AMT-1 has outstanding transient response--all the way up to 20 kHz.

 

I'm not trying to lay out why you should buy one thing or the other, in reality I'm only trying to point out that there is a lot of potential for sound quality improvement that's available--and at relatively low cost, without resorting to high priced horns/drivers (like the K-510 with an attached driver that you'll want to replace soon).  Right now, there is a dearth of options for good horns (IMHO) that can be avoided using something like an AMT.  Note that there are also downsides to the AMTs:

  1. they don't have much vertical coverage, so you'll need to aim the AMT at your listening position and position them near your sitting head height.
  2. they are dipole radiators (which is actually an advantage in that it will preclude the need for tube electronics to add "magic"...a.k.a., tight reverb, that adds depth to the soundstage) but they really need to be spaced a little distance from the front wall--like a couple of feet--in order to maximize that effect.  This is an issue when considering that the bass bin performs better when touching the front wall, getting quarter-space boundary gain.
  3. I wouldn't try to use AMT-1s in a two-way configuration if you're going to be listening at 100+ dB much of the time, since there is a rise in harmonic distortion below 2 kHz when driven at 100-105+ dB levels at the listening position.  (The way around that is to use the Cornwall's K-600 horn and K-55 driver up to 2 kHz, then cross over to an AMT-1. This is easy to do with a DSP crossover having at least 2 input channels and 6 output channels.)

Chris

Wow. That took awhile to type.  Thanks for all that info.  Decisions decisions.  I see the potentials, but I hadn't planned on using a active crossover and crites doesn't offer a 2way motor board for that kind of horn, so I would have to cut that myself.  Just trying to make things easy.  Thanks again for clearing that up.

Share this post


Link to post
Share on other sites

Do you think I would get the same smooth pattern with the ALK universal?

Share this post


Link to post
Share on other sites

The smoothness of response is more a function of which drivers/horns that you use than the passive crossover, which really can't do much about rough frequency response.  Any drivers/horns having rough frequency response is something that you typically want to avoid for home hi-fi use. You don't actually need flat response, but rather smooth response.

 

BTW: the comments about EQ of K-510 requiring EQ, etc. are usually overzealous in their recommendations.  It turns out that one or two parametric EQ filters (PEQs) in a DSP crossover are usually enough to correct the response of controlled coverage horns (i.e., the kind that you actually want to use for higher fidelity).  Here's an example using a ZXPC horn from ebay that needs only one treble PEQ and one crossover PEQ (also called a notch filter if used in passive crossover filters). 

 

 

However, the real power and ease of application is a DSP crossover that can dial these in--in a couple of minutes while bi-amping the loudspeaker (two way) or tri-amping (three way).

 

Using first order filters with an AMT-1 (in two-way operation) doesn't require higher order passive crossovers like Al K. makes.  Instead, you need one capacitor on the HF channel of the proper value, and one inductor of the proper value--that's it.  Then all you need to worry about is some way to (usually) pad down the HF driver to match the overall output level of the bass (woofer) channel.

 

But if you're looking to smooth the response further (like I elected to do with the AMT-1), then you need a DSP crossover--such as a miniDSP 2x4 HD (one box handles two two-way speakers).  Then you put your good amplifier on the HF channels, and you can use a much lower quality amplifier for the LF channels.

 

Chris

Share this post


Link to post
Share on other sites
2 hours ago, Chris A said:

The smoothness of response is more a function of which drivers/horns that you use than the passive crossover, which really can't do much about rough frequency response.  Any drivers/horns having rough frequency response is something that you typically want to avoid for home hi-fi use. You don't actually need flat response, but rather smooth response.

 

BTW: the comments about EQ of K-510 requiring EQ, etc. are usually overzealous in their recommendations.  It turns out that one or two parametric EQ filters (PEQs) in a DSP crossover are usually enough to correct the response of controlled coverage horns (i.e., the kind that you actually want to use for higher fidelity).  Here's an example using a ZXPC horn from ebay that needs only one treble PEQ and one crossover PEQ (also called a notch filter if used in passive crossover filters). 

 

 

However, the real power and ease of application is a DSP crossover that can dial these in--in a couple of minutes while bi-amping the loudspeaker (two way) or tri-amping (three way).

 

Using first order filters with an AMT-1 (in two-way operation) doesn't require higher order passive crossovers like Al K. makes.  Instead, you need one capacitor on the HF channel of the proper value, and one inductor of the proper value--that's it.  Then all you need to worry about is some way to (usually) pad down the HF driver to match the overall output level of the bass (woofer) channel.

 

But if you're looking to smooth the response further (like I elected to do with the AMT-1), then you need a DSP crossover--such as a miniDSP 2x4 HD (one box handles two two-way speakers).  Then you put your good amplifier on the HF channels, and you can use a much lower quality amplifier for the LF channels.

 

Chris

That all sounds great to get the most out of the cornscala, but more involved than I would like to get.  I like to keep things simple.  I had in mind the Mahl tweeter/faital or selenium driver with crites m2480 horn and maybe emminance kappa lf3015 woofers. ALK universal.  Not sure this combo would get good results thou .    2way would be faital 140 m2380 and the emminance 3015lf.  

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...