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What to do with Some nice Cornwall IIIs? Part Deux...


aceinc
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As mentioned in another thread "What to do with Some nice Cornwall IIIs?I have acquired a very nice looking pair of Cornwall IIIs. I am an audio hobbyist, not an audiophile. I like to tinker. I think I can make things better, which I sometimes can.

 

Which brings me to the potentially controversial point of this thread. Should I tweak the Cornwall IIIs?

 

I have yet to pop the woofer out of one yet, but in looking in the port, feeling the cabinets while they are playing and knuckle raps, there may not be much bracing and "sound damping" material in the cabinet. Additionally in tapping the midrange horn it has a plastic "ring" to it, which sounds like it is in the bandpass of the speaker. Has anyone pulled the woofer out and poked around a CW III?

 

My thoughts on tweaks are all physical (not electronic);

 

  1. Add 1" x 2" hardwood bracing.
  2. Put either egg crate foam or rock wool on the walls leaving room for the port to breath.
  3. Apply 1/4" mass loaded vinyl rubber to the outsides of the body of the horn(s)
  4. If the woofer frame is stamped steel, apply  mass loaded vinyl rubber to the to the woofer frame.

 

The main purpose of the tweaks is to reduce any coloration of the sound reproduced by the "deadening" the cabinet and anything which might resonate. I would expect these changes would improve the SQ somewhat, but not dramatically change the characteristics of the speaker.

 

One of the dilemmas is; If i execute all of these tweaks with utmost precision, nothing will be visible externally, however the speakers will no longer be "original." Since these speakers are large, and I am not sold on whether they can replace my existing main speakers I may be selling them soon. People who know Vintage Klipsch may be put off by the tweaks, decreasing their value.

 

On the other hand If the tweaks make a positive difference it may make me want to keep them.

 

What are your thoughts?

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Relax, sleep, study, work or meditate with the crackling sounds and views of a burning fire. This Ultra High Definition (UHD) video of a fireplace can be used to create a peaceful and calming atmosphere and bring a feeling of warmth and coziness in your home or place of work.

 

 

 

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58 minutes ago, moray james said:

Relax, sleep, study, work or meditate with the crackling sounds and views of a burning fire. This Ultra High Definition (UHD) video of a fireplace can be used to create a peaceful and calming atmosphere and bring a feeling of warmth and coziness in your home or place of work.

 

 

 

Sure, now you've got me thinking about who is changing the logs, and without a fireplace screen is the entire building going to burn down. Good job😰

 

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Welcome.

 

I would first decide if they have a long term place in your system.  If they do, yes tweak and brace away.  If not, then leave them alone; they’d be easier to sell unmolested.

 

And get a video of a fire extinguisher, just in case.

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11 hours ago, aceinc said:

The main purpose of the tweaks is to reduce any coloration of the sound reproduced by the "deadening" the cabinet and anything which might resonate. I would expect these changes would improve the SQ somewhat, but not dramatically change the characteristics of the speaker.

I'd be surprised if you hear any change at all--to be honest. 

 

One issue in what you're proposing is that you're also not proposing to measure the effects of your tinkering at the same time to see if you're introducing SPL response issues.  [This seems to be a systemic problem with "tinkerers" here on this forum (but not on some other forums).]  Buy yourself a calibrated microphone (I recommend a UMIK-1) and start measuring the output with Room EQ Wizard (i.e., "REW", an outstanding shareware application).  I think that you'll find that changing the room placement slightly, moving around the furniture, and adding a little absorption and perhaps diffusion at the right places will be much more effective than all of your proposed fixes detailed above. 

________________________________________________________________________________

 

As far as the Cornwall itself, in my view the loudspeaker has perhaps three issues:

  1. the tweeter is a little harsh, although this is difficult to see in REW measurements
  2. the midrange horn is a little outdated (relative to the Cornwall IV)
  3. the tweeter to midrange time alignment is off by a factor of 2-3 full wavelengths at the crossover frequency--nominally 5 kHz.

(Note that I didn't say anything about the bass bin or woofer performance, which is all that you proposed to address, above.)

 

These issues can be corrected, but what you'll wind up with is a different sounding loudspeaker if you correct the issues, for instance: 

  • Tri-amping with a DSP crossover will be able to correct item #3, above (or moving each tweeter to the top and the back of its cabinet, then dialing in the position finely using measurements to get the tweeter in the right place for midrange time alignment).
  • Changing to a K-510 horn and good 2" compression driver, which eliminates items 1 and 2 above (i.e., thus changing to a two-way and bi-amping), and thus produces a really outstanding sound reproducer.  You could do this by placing the mid-high K-510-like horn with 2" compression driver on top with the bass bin either upright or lying on its side to get the mid-high horn/driver closer to the woofer.

These two changes will not permanently affect the configuration of the Cornwall IIIs that you have--i.e., it's quite easy to reverse the changes if you're going to sell them. 

 

These are improvements--ones that you can measure and definitely hear.  However, it does require that you learn to do some things that you probably don't know how to do presently.

 

Chris

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2 hours ago, Chris A said:

I'd be surprised if you hear any change at all--to be honest. 

 

One issue in what you're proposing is that you're also not proposing to measure the effects of your tinkering at the same time to see if you're introducing SPL response issues.  [This seems to be a systemic problem with "tinkerers" here on this forum (but not on some other forums).]  Buy yourself a calibrated microphone (I recommend a UMIK-1) and start measuring the output with Room EQ Wizard (i.e., "REW", an outstanding shareware application).  I think that you'll find that changing the room placement slightly, moving around the furniture, and adding a little absorption and perhaps diffusion at the right places will be much more effective than all of your proposed fixes detailed above. 

________________________________________________________________________________

 

As far as the Cornwall itself, in my view the loudspeaker has perhaps three issues:

  1. the tweeter is a little harsh, although this is difficult to see in REW measurements
  2. the midrange horn is a little outdated (relative to the Cornwall IV)
  3. the tweeter to midrange time alignment is off by a factor of 2-3 full wavelengths at the crossover frequency--nominally 5 kHz.

(Note that I didn't say anything about the bass bin or woofer performance, which is all that you proposed to address, above.)

 

These issues can be corrected, but what you'll wind up with is a different sounding loudspeaker if you correct the issues, for instance: 

  • Tri-amping with a DSP crossover will be able to correct item #3, above (or moving each tweeter to the top and the back of its cabinet, then dialing in the position finely using measurements to get the tweeter in the right place for midrange time alignment).
  • Changing to a K-510 horn and good 2" compression driver, which eliminates items 1 and 2 above (i.e., thus changing to a two-way and bi-amping), and thus produces a really outstanding sound reproducer.  You could do this by placing the mid-high K-510-like horn with 2" compression driver on top with the bass bin either upright or lying on its side to get the mid-high horn/driver closer to the woofer.

These two changes will not permanently affect the configuration of the Cornwall IIIs that you have--i.e., it's quite easy to reverse the changes if you're going to sell them. 

 

These are improvements--ones that you can measure and definitely hear.  However, it does require that you learn to do some things that you probably don't know how to do presently.

 

Chris

While I did not propose before & after analysis, I assumed this is common practice to the point of not mentioning it. I

I am not as diligent about recording my results (my scientific method is suspect) I do use REW with a calibrated microphone and do before & after graphs. If you look at the other post, you'll see an REW graph of the speakers in their current environment. I fully admit my knowledge & expertise in electronics is limited, however I do try to crowd source to compensate.

Triamping with DSP is not a potential solution for my situation. Although if I put this into the main system, the sound processor has Audyssey which will do room correction at the macro level.

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6 hours ago, DizRotus said:

Welcome.

 

I would first decide if they have a long term place in your system.  If they do, yes tweak and brace away.  If not, then leave them alone; they’d be easier to sell unmolested.

 

And get a video of a fire extinguisher, just in case.

 

3 hours ago, VNC Studio said:

Maybe focus on room treatment and speaker isolation first rather than potentially damaging the speakers.

This brings up the cart & horse conundrum. If they don't perform better than what I have I will sell them. If it takes tweaking to make them sound better then...

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if you are having this much trouble figuring this out you should leave the CW3 alone sell them and purchase something you like better than your maggies. There are very few direct radiators which will produce the sense of size and space that a dipole does. A direct radiator loudspeaker can be modified to present a similar spatial sound as a dipole speaker but it is not a simple thing to do and you have no experience with such projects so it is not a recommended project.

   I get the feeling you would prefer a turnkey solution. Why sell your maggies anyway they are nice speakers what is it that you are looking for that they do not deliver?

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10 hours ago, DizRotus said:

Welcome.

 

I would first decide if they have a long term place in your system.  If they do, yes tweak and brace away.  If not, then leave them alone; they’d be easier to sell unmolested.

 

And get a video of a fire extinguisher, just in case.

This. And you can ship them to me. I have use for them

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The left CW III is original the right CW III is modified with additionally installed wooden bracing

 

You can use "MDF" or better "Birch tree-Multiplex" Wood for the construction. We did it from one big piece of Wood. You have to check the real distance from inside front to back, but add 2 or 3 Millimeter because front and back will move a little bit to outside when putting the construcion inside the box. One important detail/feature of the construction is to stabilize the woofer and mid-driver at his back side. Because it hangs normaly free inside the box. And this is not good. So you have to check the distance/place of the back position of Woofer and mid-driver. There we do a threaded into the wood to push the driver against the front of the loudspeaker. Now, the realy powerful movements of the driver while playing music become silent. Because of that, the dynamic become much more accurate.

 

 

 

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47 minutes ago, MicroMara said:

The left CW III is original the right CW III is modified with additionally installed wooden bracing

 

You can use "MDF" or better "Birch tree-Multiplex" Wood for the construction. We did it from one big piece of Wood. You have to check the real distance from inside front to back, but add 2 or 3 Millimeter because front and back will move a little bit to outside when putting the construcion inside the box. One important detail/feature of the construction is to stabilize the woofer and mid-driver at his back side. Because it hangs normaly free inside the box. And this is not good. So you have to check the distance/place of the back position of Woofer and mid-driver. There we do a threaded into the wood to push the driver against the front of the loudspeaker. Now, the realy powerful movements of the driver while playing music become silent. Because of that, the dynamic become much more accurate.

 

 

 

I was looking for pictures of the inside of the CW III. Thanks for posting this video.

Is the foam shown inside the cabinets in the video original, or added?

 

I noticed the chips in the cabinet around the horns. Is this likely to happen when I remove the horns? Is there anything I could do to avoid it?

 

It appears you brace the front & back panel only. Is there any concern about the top & sides?

 

Do you have any other photos or videos of the CW III tweak/upgrade process?

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Had some inside picture from the CW III`s somewhere, but need to find them first. It´s the original foam . Normal wood screws are used. It is normal that these  leave chips in the cabinet. This happens when you screw in the screws. Just screw the screws on the horns carefully, nothing happens . The front and rear of the cabinet have the greatest natural resonances. These must be reduced. The top / bottom and side panels are statically stable. You can get in touch with : mail@der-klangarchitekt.de . They speak englisch .

 

 

 

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