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Swapped K33Bs for Kappa15c


mwiener

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All,

 

I got some birthday money and decided to take the plunge.  PE had a sale on the Kappa15c over Thanksgiving so I picked up a pair for $100 each.  Put them into my 79 LaScalas which I have both the bass bin mod and the ALK universal cross overs.  My initial reaction was to immediately swap them back.  There was a noticeable loss in bass.  Then I started looking at the measurements.  I had an un natural 3db boost down at 43-44db with the K33b drivers,  That was hard to let go, but in my back of my mind I always knew that what I was hearing was not the way the recordings were supposed to be.   After listening for a while, I feel like the Kappa Cs bring a much more natural balanced sound.  I also think it does clear up the upper end of the bass to my ear.  At the sacrifice of some low end, but not a lot.  Recordings that used to sound muddy in that upper bass range sound less so.  Not a huge improvement, but I would say a subtle and noticeable improvement.  It's interesting now, every time I put something on for a critical listen, I tell myself the bass is missing.  Then with the first low note, I immediately change my mind.  With the K33b drivers there was almost always a low end presence that you always knew was there.  The Kappa15c drivers produce those low notes without that noticeable low end rumble.

 

The Kappa15c drivers are a drop in replacement.  That was about as easy as it could be.  I spent more time making a set cables to connect the new drivers than I did swapping them out.

 

I did some measurements both before and after.  I literally took a measurement, put my iPad fft recorder on pause, made the changes and took the second measurement all in a 4 hour period.  That way there was no question that all the settings were exactly the same when I took the measurements.

 

I noticed in several of the other posts that there was a lack of info comparing the two.  Hopefully the frequency plot below showing both the K33b and the Kappa15c will help.

 

Red is the Kappa15c, the other color is the K33b.

 

https://app.box.com/s/uyyechrmtbi28v5z5xxszhyipav3woge

 

Mike.

Edited by mwiener
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I know some woofers require a bit of break in time before they loosen up and sound their best. I'd recommend re-taking the measurements once you've logged at least 40 hours on the new drivers, you may get a little more low end output.

Edited by jjptkd
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I know some woofers require a bit of break in time before they loosen up and sound their best. I'd recommend re-taking the measurements once you've logged at least 40 hours on the new drivers, you may get a little more low end output.

 

I have some Eminence Delta 10A 10" pro mid/bass drivers that were just awful out of the box.  Low output, very tinny sounding, no bass whatsoever.  Mine took about 100 hours to break-in, now they sound great. 

 

For the record, some people don't believe in break-in for speakers and that's OK.  I have come to the conclusion that it's different for different speakers.

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Put them into my 79 LaScalas which I have both the bass bin mod and the ALK universal cross overs.
     What are your port dimensions and have you changed them since swapping in the 15c's?

 

 

Zim,

 

I have not changed the ports at all.  I have 4” diameter flared ports.  PE part number  268-352.  The ports have an 8” port length instead of 7”.  They actually are 9” overall, but the port mfg tells you not to count the length of the flare on both ends.  I am waiting for the software I use to have an impedance testing adapter for my test setup before I start playing with port tuning.

 

 

I came up with a better analogy for the K33bs versus the Kappa15cs.  I am sure everyone has used the loudness button popular on old mid/low end equipment.  When you hit the loudness button at a moderate volume you get an exaggeration of the low frequencies along with distorted bass.  With the K33bs installed it sounds like that exaggerated low end.  There is no distorted bass, but you do faintly hear the exaggerated low end.  The Kappa15c drivers don’t have that audible low end exaggeration, but they do carry almost all of the same bass content.  I doubt I will be swapping them back.  I am pretty happy with the Kappa 15c drivers.

 

I do plan on taking another measurement after I get some hours on them.  I have about 30 or so hours now.  Should be at the break in point about the 1st of the year.

 

Mike.

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