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Super Cornwall 1.0


ClaudeJ1
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On 11/25/2018 at 10:36 AM, jjptkd said:

 

Wow, I'm quite shocked by this, to me the step up from the k-601 in the Chorus 1 to the k-501? (CF-3/4 horn) was pretty significant in a much larger presentation and lower tone, closer to the La Scala mid in comparison, would have thought this would have been one of the main design goals. 

I'm not disputing that it's a better mid range for you, it's just that publishing a mod that doesn't require making any sawdust is easier to do and is a better "bang for the buck." A newer, bigger throat,  mid range will be done in V. 2.0.......................maybe. Or just go buy a Cornwall IV when it's released, that seems to be the way to go for a true Klipsch fan anyhow, vs. a cheapskate DIY guy like me! (there are more of us than your think). Besides, it's only money, right? Don't worry, you'll make more.

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On 8/31/2018 at 8:35 PM, ClaudeJ1 said:

I disagree with your assessment of the K55 driver. It's a tough one to beat because it's only 1" driver I know of that gets down to 300 Hz. The 2" alternatives are expensive and are restricted by the lack of cabinet depth.

Actually I don't get it. 2 inch throat tractrix is shorter than same F3 tractrix with 1 inch throat.

So easier to fit 2inch driver plus horn

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28 minutes ago, Bacek said:

Actually I don't get it. 2 inch throat tractrix is shorter than same F3 tractrix with 1 inch throat.

So easier to fit 2inch driver plus horn

Depends on the magnet structure of the driver. You guys are all looking for a magic pill, where this is none. It's acoustics working in concert with electro-mechanical transducers for a given bandwidth and dispersion angle with the lowest distortion and flattest response possible. There are many, many ways to get there or fall short. Plus it has to fit in a decent sized box, whatever that means.

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I'm not talking about driver I'm talking only about a horn. 300hz cutoff tractrix horn for 2 inch driver is shorter by 12cm then 1 inch version. I guess it will allow to fit any 2 inch driver in cabinet capable of fitting 1inch driver horn combination.

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On 11/4/2019 at 3:22 PM, ClaudeJ1 said:

these suckers KICK some BOOTAY ROYALE in the bass department, almost like adding a subwoofer, since the output below 30 Hz

I NEED this.   I'll be joining the party soon. I already swapped the tweeters with Dave A MAHLs and DE10 tweeters.   I LOVE this combo as I have posted elsewhere and spent plenty of time listening on two sets of speakers now to fully recommend this upgrade.   Great work gentleman. I ordered the woofers today as well 

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12 hours ago, ClaudeJ1 said:

I'm not disputing that it's a better mid range for you, it's just that publishing a mod that doesn't require making any sawdust is easier to do and is a better "bang for the buck." A newer, bigger throat,  mid range will be done in V. 2.0.......................maybe. Or just go buy a Cornwall IV when it's released, that seems to be the way to go for a true Klipsch fan anyhow, vs. a cheapskate DIY guy like me! (there are more of us than your think). Besides, it's only money, right? Don't worry, you'll make more.

Hi claude.  The kappalite 3015lf-4 you speak of for the cornwall upgrade, would that woofer be a good pick for a cornscala?     

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3 hours ago, mopardave said:

Hi claude.  The kappalite 3015lf-4 you speak of for the cornwall upgrade, would that woofer be a good pick for a cornscala?     

YES, of course, since it's, essentially, the same box and port volume.

 

Horn loading any of the Eminence drivers reduces the cone excursion. The venerable Klipshorn was once built out of Clear Plexiglas so that PWK could VISUALLY (laser interferometry??) measure the actual woofer excursion (Xmax) at what he considered "full acoustic output" (120 db??) This was found to be about 1/16th of an inch (1.5 mm), which the Kappa 15C can easily do with it's 2.5 mm Xmax specification, even in a LaScala or Belle. The Kappalite 3015 LF-4, with it's super strong magnet as well as greater mass (and mass rolloff) is the perfect driver for Bass Reflex. Eminence literature even says so. WHY? because of it's almost 11 mm Xmax capability. Yes it produces more IM distortion than a Khorn, but even with PWK's use of the same K-33 driver for a Khorn AND a Cornwall, you had the same performance differential of the two radically different types of enclosures. So, basically, then, that part of the design a wash, since we are all aware of those trade-offs.

 

IOW, for a similar acoustic output, you can't change the inherent distortion characteristics of a Bass Horn vs. a Bass Reflex, but by allowing the driver to have greater Xmax, you get a slightly lower cutoff frequency in a Cornwall box and port resulting in more bass output overall, while handling more WATTS in the process, according to the manufacturer specification. This is never a problem with modern solid state amplifiers, now is it? The reason that this woofer costs more is it can handle more power with those heatsink fins and Neo magnet, but in Home Use, you won't be straining them much, even at "stupid loud" levels, which I've already tried!!

 

I got mine to "disco levels" with only 30 Watts. I know this, since my Super Cornwalls have built in LED meters on the front panels to monitor the input at the speaker terminals!! This coincides with the roughly 6 db difference in sensitivity between a Cornwall and a Klipshorn (meaning a Khorn would need only 7.5 watts to do the same thing, hence, it's lower IM distortion). The Cornwalls, with K33's have always been able to produce what many reviewers have called "AWESOME BASS," this driver just make it just a little more awesome.......................dare we say "SUPER Awesome?"

 

Again, everyone has different size ROOMS, and a different definition of "Stupid loud." But that is beyond the scope of this text..............................

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11 hours ago, ClaudeJ1 said:

YES, of course, since it's, essentially, the same box and port volume.

 

Horn loading any of the Eminence drivers reduces the cone excursion. The venerable Klipshorn was once built out of Clear Plexiglas so that PWK could VISUALLY (laser interferometry??) measure the actual woofer excursion (Xmax) at what he considered "full acoustic output" (120 db??) This was found to be about 1/16th of an inch (1.5 mm), which the Kappa 15C can easily do with it's 2.5 mm Xmax specification, even in a LaScala or Belle. The Kappalite 3015 LF-4, with it's super strong magnet as well as greater mass (and mass rolloff) is the perfect driver for Bass Reflex. Eminence literature even says so. WHY? because of it's almost 11 mm Xmax capability. Yes it produces more IM distortion than a Khorn, but even with PWK's use of the same K-33 driver for a Khorn AND a Cornwall, you had the same performance differential of the two radically different types of enclosures. So, basically, then, that part of the design a wash, since we are all aware of those trade-offs.

 

IOW, for a similar acoustic output, you can't change the inherent distortion characteristics of a Bass Horn vs. a Bass Reflex, but by allowing the driver to have greater Xmax, you get a slightly lower cutoff frequency in a Cornwall box and port resulting in more bass output overall, while handling more WATTS in the process, according to the manufacturer specification. This is never a problem with modern solid state amplifiers, now is it? The reason that this woofer costs more is it can handle more power with those heatsink fins and Neo magnet, but in Home Use, you won't be straining them much, even at "stupid loud" levels, which I've already tried!!

 

I got mine to "disco levels" with only 30 Watts. I know this, since my Super Cornwalls have built in LED meters on the front panels to monitor the input at the speaker terminals!! This coincides with the roughly 6 db difference in sensitivity between a Cornwall and a Klipshorn (meaning a Khorn would need only 7.5 watts to do the same thing, hence, it's lower IM distortion). The Cornwalls, with K33's have always been able to produce what many reviewers have called "AWESOME BASS," this driver just make it just a little more awesome.......................dare we say "SUPER Awesome?"

 

Again, everyone has different size ROOMS, and a different definition of "Stupid loud." But that is beyond the scope of this text..............................

Sweet!  Thanks Claude.  These will have the B&C 120 and 85 drivers with an ALK universal.  Kappa 3015-4 it will be.  I see that woofer is also offered in an 8ohm, any difference between the 2?

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13 minutes ago, mopardave said:

Sweet!  Thanks Claude.  These will have the B&C 120 and 85 drivers with an ALK universal.  Kappa 3015-4 it will be.  I see that woofer is also offered in an 8ohm, any difference between the 2?

Since the name of the game for bass reflex is to pull as much current as possible from the power amp to try and "catch up" downard attenuated horns, you NEED the 4 ohms to do that. Using 8 ohm woofers would make matters worse, so no 8 ohms woofers need apply. This is true for all speakers with Solid State amps. BTW. Tubes and bi-amping are another matter altogether and also beyond the scope of this text.........(can you tell I like this expression?).

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46 minutes ago, ClaudeJ1 said:

Since the name of the game for bass reflex is to pull as much current as possible from the power amp to try and "catch up" downard attenuated horns, you NEED the 4 ohms to do that. Using 8 ohm woofers would make matters worse, so no 8 ohms woofers need apply. This is true for all speakers with Solid State amps. BTW. Tubes and bi-amping are another matter altogether and also beyond the scope of this text.........(can you tell I like this expression?).

Yeah, that's cool.  I will be sure to get the 4ohm versions.  Thanks again claude.  Glad I waited on buying woofers. Was gonna get the 15c.

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On 11/25/2018 at 1:01 PM, ClaudeJ1 said:

When you throw cost into the equation, spending the extra $800-1,000 it takes for new mid horns and drivers kicks in a cost/benefit ratio that is pretty low vs. all the other aspects of the mod. So, where do we stop?? No question that a 2" modern horn and driver are superior to the venerable K600/K55 combination in the distortion department, but not bandwidth. (If K600 is so "bad" why did Bob Crites spend huge money to refurbish the tool to make more K600's under his own name?, or even sell a new K55G in the process??). So, I sincerely doubt that someone would buy a pair of used Cornwalls and add $1,700 worth of mods with diminishing returns. I'd like to keep the cost of the mods about the same as the cost of the used Cornwalls BEFORE the remaining parts are sold on Ebay. If someone wants to go further (Super Cornwall 2.0??) after that, they can request I turn loose all my curves on 2" driver and horns..............fair enough???

 

Said like a true photographer....  engineer!

 

:emotion-21:

 

(seriously, the attention to your detail is superb!!)

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On 11/5/2019 at 12:17 PM, Bacek said:

I'm not talking about driver I'm talking only about a horn. 300hz cutoff tractrix horn for 2 inch driver is shorter by 12cm then 1 inch version. I guess it will allow to fit any 2 inch driver in cabinet capable of fitting 1inch driver horn combination.

Yes, that is usually the case. Agreed. Look at SEOS horns and you will see they support your observations here.

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Cant wait to see these done with the MAHLs in so that you can get moving on the super Cornwall 2's.  LOL.  I have a set of non super Cornwall 2's that are waiting.  Woofers have been on the shelf, goldwood 450's and other various horns and Dave shipped me out a pair of the large MAHL V2's last night, so lets get moving Claude!  LOL  Love your work!

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14 minutes ago, Pete H said:

Cant wait to see these done with the MAHLs in so that you can get moving on the super Cornwall 2's.  LOL.  I have a set of non super Cornwall 2's that are waiting.  Woofers have been on the shelf, goldwood 450's and other various horns and Dave shipped me out a pair of the large MAHL V2's last night, so lets get moving Claude!  LOL  Love your work!

I got a big laugh about "let's get moving." Thanks for that and the rest of it. It is encouraging, but most likely after the holidays.

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3 minutes ago, ClaudeJ1 said:

I got a big laugh about "let's get moving." Thanks for that and the rest of it. It is encouraging, but most likely after the holidays.

I was laughing when I typed it.  I completely understand as i typically have 20 different things going on which is why I have parts that have been on shelves for a while.  Not to get sidetracked about the super 2, just wondering if you have considered what mid driver yet?  

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1 hour ago, Pete H said:

I was laughing when I typed it.  I completely understand as i typically have 20 different things going on which is why I have parts that have been on shelves for a while.  Not to get sidetracked about the super 2, just wondering if you have considered what mid driver yet?  

Too many options, not enough time right now.  But I did have time to update the Tweeters with DaveA's sMAHL 2.0 lenses, since they curved so well, I thought I would listen for while, so you can go back and revisit the first post, as of 11/9/2019 today!

 

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5 hours ago, Randyh said:

can you please update us on the build components so far -

DaveA's latest Tweeter,  sMAHL with B&C DE-120 driver, Eminence  Eminence Kappalite 3015 LF-4, and recap your Crossover. Also think about going to 4 uF on the tweeter instead of 2 uF, the compromising of you may choose a 3 uF or a 3.3 uF for the super picky!!

 

 But why didn't just go to the first post, which I updated? Also, the DASH FOUR means it's 4 ohms, not 8 ohms, in case there is further confusion about the difference. It's not a religion with me, but I don't believe in ever using 8 ohm woofers, unless you are using 2 of them in Parallel in one cabinet. Almost all modern amplifiers (except for stupid tube amps) are designed to work with 2-4 ohm loads. As a matter of fact, if you adapt a Car Amplifier for home, they can drive 1 ohm (not for the squeamish, though).

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