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MikeFord

Epic CF-4, tweeter down

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Short version; CF-4 needs tweeter diaphragm or driver replaced.

 

My usual snails pace, over the last three days I finally shuffled around our living room and parked my Forte's and hooked up the set of Epic CF-4 speakers I bought about a year ago.

 

These are freaking heavy speakers, 108 lbs each, much grunting and groaning, finally hit play and ..... one tweeter isn't working. OTOH seems like the other 5 drivers are fine, but a bit more checking is on the table before I do anything. Not fair to compare with one bad tweeter, but the sound is VERY different from my Forte speakers.

 

Anybody has a spare tweeter driver that is known good, I will either buy or send mine off to Crites for repair. I may do that regardless, but I am also considering use of EV DH1506. Kicking myself on the EV as there was a pair local to me for $75 and I was too busy to go buy them. I always like to get a good item back to proper stock operation condition before making any changes, but I do have the usual list of mods at the back of my mind.

 

These are not the first version, info I think is in my sig. Ultimately they will be used with a subwoofer with the mains high passed no lower than 60 hz, so the ports may not matter.

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1 hour ago, MikeFord said:

but I am also considering use of EV DH1506. Kicking myself on the EV as there was a pair local to me for $75

Agree, you missed it.  :(

 

According to Crites website, the K-63  can no longer be repaired because the diaphragm is no longer available.

 

I have CF-4's with the 1506.  It's a nice upgrade but not huge and I would say the going rate for those 1506 pr is $200 shipped, when you can find them.  Any less than that and you found a deal!  A pair will fit nicely into a USPS pre-paid box at $16.35.  They come up on the used market regularly but not frequently.  When I was looking it took 3 months to find them.

 

I've already sold my K-63-KN or I would offer them to you.  I sold my pair to forum member @Sammyd.  You might reach out to him to see if he has a single.

 

The 1506 will not require XO mods and screws right in.  It is heavier than stock so putting in a brace or shelf for them to sit on is recommended.  The K-63 weighs 4 pounds, the 1506 is 12 pounds, you don't want to crack that horn lens.  You can see the shelf in the pic below.  It is the cross brace that has the thicker wood holding the shelf.  I used pine 1x3 or 1x4, and I think it was the latter.  Don't use MDF.

 

My horn lens has 11oz of clear Pure silicon caulk on the back.  If you mod your lens like I did, use the PURE silicon caulk.

 

 

58f1c03d16378_EVDH1505andK-63IMG_4292.JPG.579087c256d76609c7c31340c8c8d2dd.JPG

EV DH1505 and K-63  IMG_4281.JPG

EV DH1505 and K-63 IMG_4285.JPG

IMG_4347.JPG

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Living in Socal has its perks, one is that there are hundreds of studios and sound companies. I've even seen, back in the day where I had zero idea of what they were, TAD drivers at a local swap meet along with a bunch of gear from a guy who specialized in gutting out old studios. Now I have list of stuff to keep an eye out for, but don't see that much lately. Ebay is the bane of good local deals.

 

Why pine vs mdf, pine and most solid wood will have big resonance point?

 

 

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1 hour ago, MikeFord said:

Why pine vs mdf, pine and most solid wood will have big resonance point?

I was told to use a hard wood when making braces, it doesn't necessarily have to be pine.  MDF being essentially saw dust doesn't have much structural strength when cut into narrow strips.

 

I am not worried about the resonance of the brace, but think of the outside surface as if it were a drum head.  If you give it the "rap test" with your knuckles (I use a drum stick because I can hear the pitch more clearly) you will notice a certain sound.  If you brace (dampen) the surface with your hand the pitch changes and does not vibrate as much. 

 

I braced the cab with the idea I wanted to reduce a non-accurate nasal sound and some harshness I heard in the HF that I wanted to get rid of.  With the addition of the bracing, the 1506, the damped horns and some fibre fill the pitch came down about 1/3 of an octave and the CF-4's became the most accurate speakers I have ever heard.

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8 hours ago, MikeFord said:

Short version; CF-4 needs tweeter diaphragm or driver replaced.

 

My usual snails pace, over the last three days I finally shuffled around our living room and parked my Forte's and hooked up the set of Epic CF-4 speakers I bought about a year ago.

 

These are freaking heavy speakers, 108 lbs each, much grunting and groaning, finally hit play and ..... one tweeter isn't working. OTOH seems like the other 5 drivers are fine, but a bit more checking is on the table before I do anything. Not fair to compare with one bad tweeter, but the sound is VERY different from my Forte speakers.

 

Anybody has a spare tweeter driver that is known good, I will either buy or send mine off to Crites for repair. I may do that regardless, but I am also considering use of EV DH1506. Kicking myself on the EV as there was a pair local to me for $75 and I was too busy to go buy them. I always like to get a good item back to proper stock operation condition before making any changes, but I do have the usual list of mods at the back of my mind.

 

These are not the first version, info I think is in my sig. Ultimately they will be used with a subwoofer with the mains high passed no lower than 60 hz, so the ports may not matter.

There is also a possibility that the speaker taps for the highs have come loose and that is why the horn is not working. That happened to one of mine years ago, the horn stopped working. I unscrewed the 6 screws around the terminals and pulled out the crossover network and saw that the nut behind one of the terminals had come loose and so the signal was not passing through,  retightened it and then back to normal.  Worth a quick check before searching for a replacement. On another note, just to be sure, the metal jumpers between the terminals are there, right. 

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10 hours ago, wvu80 said:

The 1506 will not require XO mods and screws right in. 

Do you have any test results to verify this.  The CF-4 crossover has correction circuits in it to specifically correct the output of the K-63-KN driver.  It is hard for me to understand how those correction circuits would be right for any other driver.  Not impossible I suppose, but unlikely.

 

Bob Crites

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43 minutes ago, BEC said:

Do you have any test results to verify this.  The CF-4 crossover has correction circuits in it to specifically correct the output of the K-63-KN driver.  It is hard for me to understand how those correction circuits would be right for any other driver.  Not impossible I suppose, but unlikely.  -Bob Crites

No, I don't have any test results.  I know what you are saying and I know the frequency range to which you are referring.  I agree, it would be informative to see the charts.  Let me explain a bit more how this started.

 

When I first got the CF-4 a couple of years ago they were bone stock.  I loved the "in-your-face" articulation, in the HF section in particular, but my ears heard a couple of things.

 

1.  They were not accurate.  IE, a piano did not sound like a piano, it was a bit nasal.

2.  I could hear a harshness in the HF.  Once I heard it, I could not "un-hear it" if that makes any sense.  The harshness bothered me every time I listened.

 

I read on this forum how some others had modified their CF-4 with the EV DH-1506.  The K-63 screwed off easily, the 1506 screwed back in neatly.  Others had suggested the 1506 was a "magnitude" better than the stock K-63.  Although I wanted to hear an improvement there was either little or none.  With the K-63 on the left speaker and the 1506 on the right, I couldn't honestly say one was better than the other.  They each sounded like the other, with maybe a little better sound with the 1506.  Mustang Guy listened to them and felt the same way.

 

I then made a lot of little changes. 

  • Braced the cabs, little audible change. 
  • Damped the horns with a tube of silicon caulk.  It made an audible difference in the "knuckle rap test" but no discernible difference in A/B test.
  • Removed two of the 3/4" foam sheets in the bottom of the speaker, added back in about a pound of polyfil.  I believe the polyfil was the single best thing I did, even though I knew I was likely losing some efficiency

At this juncture they were sounding real good.  I added a 15" sealed sub and they went from good speakers to great.  There now was incredible dynamics even with my decade old Pioneer AVR.  The harshness was GONE, the accuracy to my ears was now the best I have ever heard.  In terms of reproducing the full range of a piano these easily bested my 1978 Khorns, stock or modified.

 

I believe all the little changes and the big change to the 1506 made a BIG audible change overall.  That is totally anecdotal, totally my opinion,  I don't have the skill or the equipment to test them but I would also like to see some results if they were available.

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A little Google did not locate TS parameters for the DH1506, but EV does have data sheets that show eq networks, but all before the amp, not directly to the speaker.

 

OTOH how different are various HF compression drivers? Seems to me most are made to roughly be interchangeable.

 

Any tricks or gotchas I should be aware of when opening these speakers up (pulling the tweeter and checking the crossover)?

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2 hours ago, MikeFord said:

A little Google did not locate TS parameters for the DH1506, but EV does have data sheets that show eq networks, but all before the amp, not directly to the speaker.

 

OTOH how different are various HF compression drivers? Seems to me most are made to roughly be interchangeable.

 

Any tricks or gotchas I should be aware of when opening these speakers up (pulling the tweeter and checking the crossover)?

See .PDF attached for 1506 specs.  It does list a XO with charts and graphs but I didn't see TS parameters.

+++

dh1506.pdfdh1506.pdf

Some CD's are legitimately more efficient than others.  I once added a SEOS 12 w/Denovo DNA-360 to my CF-4 just for a goofy non-scientific experiment.  In a very short listening test with some jazz recordings I could hear NO difference.

IMG_3763.JPG.74854713e465067da876acae413d2349.JPGIMG_3764.JPG.2e40591566cde88f0645db7a7c46b26c.JPG

 

+++

 

Pulling the drivers is straight forward.  Unscrew the horn from the front with a Phillips head screwdriver it will come out easily. 

 

IMG_4330.thumb.JPG.46cdde4657fc17b7dfacea89025dd2ed.JPG

If you are adding bracing then entire front motorboard will unscrew as well,

 

 

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On 4/15/2017 at 7:34 AM, shiva said:

There is also a possibility that the speaker taps for the highs have come loose and that is why the horn is not working. That happened to one of mine years ago, the horn stopped working. I unscrewed the 6 screws around the terminals and pulled out the crossover network and saw that the nut behind one of the terminals had come loose and so the signal was not passing through,  retightened it and then back to normal.  Worth a quick check before searching for a replacement. On another note, just to be sure, the metal jumpers between the terminals are there, right. 

 

BINGO

 

Pulled the tweeter horn just now and Red post was loose with the wire hanging. Checked the driver and 7 ohms, so should be good.

 

Seems weird to me, but the wire that was loose has about an inch of blue shrink and is tied in a knot (not tight).

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