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Cornwall IV


tipatina

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2 hours ago, ClaudeJ1 said:

The box resonance IS what makes the low bass below 100 Hz. If I agreed with you, we'd both be wrong. Besides, y'all are taking this way too seriously.

 

Not referring to something similar to a port tuning resonance but the box sound that escapes the port due to the old style ports.  Not box tuning such as helmholtz resonator. 

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5 hours ago, pzannucci said:

Not referring to something similar to a port tuning resonance but the box sound that escapes the port due to the old style ports.  Not box tuning such as helmholtz resonator. 

I was not referring to vent tuning at all but to vent noise generated by turbulence. All vents leak back wave upper range woofer noise from the cabinet to some degree, if the bounce is right nothing can stop that but brace work does help to brake up those reflections and can make for improvements in that regard. Passive radiators are better in this respect as the cone will both reflect/deflect some and damp a little some of those reflections. Vents are the most open to direct radiation and reflections while passives do present some resistance and damping to these noises. Vent noise is most noticeable when the vents are small causing chuffing and in some extreme cases whistling, rear placement of vents helps a great deal to reduce the obvious nature of such noises and it will result in a delay of those reflections in time reaching your ears (the longer the delay time the easier for your brain to ignore these sounds). Past the reflected upper woofer ranger reflections the only other thing that comes out of the vent is the narrow band of the tuning frequency which is usually around 5 or so Hz. wide, no other sounds come out of the vent. If you are hearing box sound they are being radiated by the box/cabinet walls. If you actually stop to consider the huge surface are of a cabinet when compared to the woofer even with the smallest of woofers and cabinets the box has a much greater radiating area and in fact  radiates more output (as noise) than the desired sound from the woofer. the highlights the extreme importance of brace work which seems especially overlooked in the audio world. When suggestions are put forward to include brace work many offer up age old and very tired comments such as "if the designer had intended them"...etc. to no end.

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I look forward to hearing both the new Cornwall IV along with the Heresy IV, myself!  But for some others, it seems they have already decided upon things without ever even hearing them, yet.  As usual, the modifications freaks are already planning their mods, it seems.  So far, though, nobody has mentioned liberal application of dynamat to all of the box panel interior surfaces...but I'm sure that is coming soon! 😉

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18 minutes ago, ClaudeJ1 said:

Ah yes, a more GENTLE air flow is presented with flares, but on the Cornwall, since the box is optimized for the K33, which has enough output up high to hand off the a higher frequency midrange point. But it's the cubic port area, and controlled reactance that makes a Cornwall, a Cornwall.  Regardless of those "Roman Number Things" that seem to follow all modern products (anyone want a Canon 5D Mark IV?).

ABSOLUTELY NOBODY IN HISTORY can beat the Brit cal .303 Lee-Enfield rifles model designations in confusing anybody...I think they INVENTED confusing designations, even to the point of RE-DESIGNATING specific models more than once!!  The Brits even have Harley-Davidson's "alphabet soup" model designations beat hands-down!! 

 

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3 hours ago, moray james said:

I was not referring to vent tuning at all but to vent noise generated by turbulence. All vents leak back wave upper range woofer noise from the cabinet to some degree, if the bounce is right nothing can stop that but brace work does help to brake up those reflections and can make for improvements in that regard. Passive radiators are better in this respect as the cone will both reflect/deflect and damp a little some of those reflections. Vent noise is most noticeable when the vents are small causing chuffing and in some extreme cases whistling, rear placement of vents helps a great deal and it will result in a delay of those reflections in time reaching your ears. Past reflected upper woofer ranger reflections the only other thing that comes out of the vent is the narrow band of the tuning frequency which is usually around 5 or so Hz. wide no other sounds come out of the vent. If you are hearing box sound they are being radiated by the box/cabinet walls. If yu actually stop to consider the huge surface are of a cabinet when compared to a woofer even with the smallest of woofer and cabinets the box has much greater radiating are and in fact in most cases radiates more output (as noise) than the desired sound from the woofer. the highlights the extreme importance of brace work which seems especially overlooked in the audio world. When suggestions are put forward to include brace work many offer up age old and very tired comments such as "if the designer had intended them"...etc. to no end.

Yes, two different problems, turbulence / pipe noise artifacts and box noise escaping through the port.  Something similar to midrange leakage.  Though based on the tuning, there can also be a resonant boominess from the box that you can hear in the CW.  The port type, length, and size can help resolve this along with quality bracing to insure it isn't from panels moving.  All this stuff does account for a quality speaker.

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1 hour ago, HDBRbuilder said:

I look forward to hearing both the new Cornwall IV along with the Heresy IV, myself!  But for some others, it seems they have already decided upon things without ever even hearing them, yet.  

 

Instead of assumptions, speculations and declarations why didn’t some of you just ask Roy to share information about the design changes...? 

 

Wouldn’t this have been a much better thread if instead some would have asked.......

 

   “Hey Roy would you tell us please what the many changes in the Cornwall IV have achieved by your Measurements Data and how does that correlate to what we may expect to experience when we have a chance to actually listen to the new design.”

 

miketn 

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11 minutes ago, Ziggurat said:

You need a date with Ian Skennerton 🙂

He's even older that I am....so I can just read his books, since the memory of most people over 70 years old requires keeping the books they write close at hand to check on what they are saying...just reading the book would probably be EASIER....and much quicker!  IMHO! 😉

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4 hours ago, HDBRbuilder said:

I look forward to hearing both the new Cornwall IV along with the Heresy IV, myself!  But for some others, it seems they have already decided upon things without ever even hearing them, yet.  As usual, the modifications freaks are already planning their mods, it seems.  So far, though, nobody has mentioned liberal application of dynamat to all of the box panel interior surfaces...but I'm sure that is coming soon! 😉

dynamat is not an effective method of damping cabinet walls except for a very few situations mostly small metal enclosures. Horns often require structural braces if straight, folded horns are by nature reasonably well braced but for high output designs bracing becomes important especially at the mouth of bass horns.

   In response to your comments with respect to the CW4 and H4, if the CW4 cabinet is approximately the same size and material build as all the other CW's then it is to be expected that the measured box talk will also be the same and likewise with the H4, what else would you or anyone else expect? This is simply stating the obvious and not an indictment of the designs they are what they are for a reason(s). All loudspeaker manufactures face the same issues and make the decisions they do based mostly upon the economics. Aftermarket DIY modification does not have to deal with the same set of constraints.

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1 hour ago, HDBRbuilder said:

He's even older that I am....so I can just read his books, since the memory of most people over 70 years old requires keeping the books they write close at hand to check on what they are saying...just reading the book would probably be EASIER....and much quicker!  IMHO! 😉

 

You speak in riddles!  I will let you off, Old Timer 😉

 

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2 hours ago, pzannucci said:

Yes, two different problems, turbulence / pipe noise artifacts and box noise escaping through the port.  Something similar to midrange leakage.  Though based on the tuning, there can also be a resonant boominess from the box that you can hear in the CW.  The port type, length, and size can help resolve this along with quality bracing to insure it isn't from panels moving.  All this stuff does account for a quality speaker.

The resonance of the box does not have to escape through the vent it radiates at very many time the active surface area of the woofer via the un braced cabinet walls. The boom/distortion you hear is the box panels resonating and all that radiation is distortion. A woofer cabinet can radiate more noise than the woofer in that cabinet outputs itself. Box talk is a serious problem and the solution is to stiffen the box so that its first structural resonant mode is placed above the pass band of the woofer in the box. How you stiffen the box is up to the designer to choose but brace work is generally the least expensive method.

   You are correct in that port size (in a vented design) and brace work will together go a long way to improving matters. Without brace work a box can only resonate, the only exception being very small cabinets using rigid wall materials.

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2 hours ago, mikebse2a3 said:

 

Instead of assumptions, speculations and declarations why didn’t some of you just ask Roy to share information about the design changes...? 

 

Wouldn’t this have been a much better thread if instead some would have asked.......

 

   “Hey Roy would you tell us please what the many changes in the Cornwall IV have achieved by your Measurements Data and how does that correlate to what we may expect to experience when we have a chance to actually listen to the new design.”

 

miketn 

He can't, @Chief bonehead is under exclusive contract to the Museum and is strictly forbidden from answering such a well formed question until AFTER the Bonehead gives his class. Kind of like baseball players only signing one brand of card.

 

First we have to know why Paul did what he did; and then we get to learn how that leads Roy to do what he does.  At least that what the Playbill says.

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On 9/9/2019 at 3:49 AM, mustang_flht said:

Here are the first images of the presentation of the Cornwall IV at the Rocky Mountain Audio Fest of Denver, but also Heresy with the new tweeter...

 

dyjr.jpg

 

 

 

 

 

 

I have not heard these yet, but logic leads me to think that the upgrades are worthwhile improvements, and if Chief bonehead says they sound better, then I believe that they sound better.

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11 hours ago, moray james said:

The resonance of the box does not have to escape through the vent it radiates at very many time the active surface area of the woofer via the un braced cabinet walls. The boom/distortion you hear is the box panels resonating and all that radiation is distortion. A woofer cabinet can radiate more noise than the woofer in that cabinet outputs itself. Box talk is a serious problem and the solution is to stiffen the box so that its first structural resonant mode is placed above the pass band of the woofer in the box. How you stiffen the box is up to the designer to choose but brace work is generally the least expensive method.

   You are correct in that port size (in a vented design) and brace work will together go a long way to improving matters. Without brace work a box can only resonate, the only exception being very small cabinets using rigid wall materials.

Agreed, my assumption (maybe wrong) is that the structural issues of the CW IV should have been mitigated.  A large paneled box with limited bracing will sound just like that, a box.

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11 hours ago, dwilawyer said:

He can't, @Chief bonehead is under exclusive contract to the Museum and is strictly forbidden from answering such a well formed question until AFTER the Bonehead gives his class. Kind of like baseball players only signing one brand of card.

 

First we have to know why Paul did what he did; and then we get to learn how that leads Roy to do what he does.  At least that what the Playbill says.

If we got answers, there wouldn't be a thread.   What fun is that.

 

What was that commercial with "Anticipation" :D

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22 hours ago, Marvel said:

I totally disliked the box boominess in the older models...

I totally agree. I had CWIII for a few months. The hump/coloration/resonance it had interfered with the midrange resolution.  Things became blurred and wooly compared to either my Forte I or Forte II, or even my Heresy III speakers.   I do not trust the CWIV will be much better in this area if it is not braced to address this issue. It probably will not be as I think there are far more Cornwall lovers than detractors.   I think some people like that resonance because it gives the illusion of a BIG sound.

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44 minutes ago, kink56 said:

I totally agree. I had CWIII for a few months. The hump/coloration/resonance it had interfered with the midrange resolution.  Things became blurred and wooly compared to either my Forte I or Forte II, or even my Heresy III speakers.   I do not trust the CWIV will be much better in this area if it is not braced to address this issue. It probably will not be as I think there are far more Cornwall lovers than detractors.   I think some people like that resonance because it gives the illusion of a BIG sound.

Bingo!

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1 hour ago, kink56 said:

I totally agree. I had CWIII for a few months. The hump/coloration/resonance it had interfered with the midrange resolution.  Things became blurred and wooly compared to either my Forte I or Forte II, or even my Heresy III speakers.   I do not trust the CWIV will be much better in this area if it is not braced to address this issue. It probably will not be as I think there are far more Cornwall lovers than detractors.   I think some people like that resonance because it gives the illusion of a BIG sound.

I agree with this statement so much it is worth repeating a third time. This is why I am a proponent for developing a Chorus III. Now I would like to hear thoughts on baffle diffraction and edge diffraction in a large box. My 30 year old JBL 250Ti solve those cabinet diffraction issues, are internaly braced and filled, and look good all at the same time. The only thing getting in the way of utilizing these well known solutions to well know issues, that I can come up with, is cost and profit margin. 

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