Extending upper frequency range of Cornwall 1

[Westeagle]

Hi Folks!

 

I recently purchased a pair of Heresy ii's and am very much enjoying them. These are my first set of Klipsch speakers after having had a prejudiced view that horns sounded harsh and honkey. Boy was I ever wrong. I really love the Heresy's and their natural aliveness.

 

So now I'm looking at upgrading, and have come across a pair of Cornwall 1's from the early 80's that are for sale. They are abut a 3.5 hour drive from me, so it's not easy to go out and just audition them.

 

From what I can gather online, some people say that the tweeter starts to drop off around 16kHz. The Heresy ii's tweeters are very satisfying to me and was wondering if these opinions I have heard about the Cornwalls were accurate? I am fortunate to be able to hear up to 20kHz, so speakers that roll off at 16k don't cut it for me.

 

It appears that I cannot find a reliable frequency response graph online to prove or disprove how high the tweeters go. The tweeters are K-77.

 

My question to the community is: do these really cut off at 16kHz, and if so, are there any 3rd party replacements for the k-77 tweeters that go up to 20kHz that would be recommended?

 

Thanks very much!

 

Westeagle

[wuzzzer]

I believe that the CT120 and CT125 tweeters from Bob Crites will extend the frequency higher than stock.

[PrestonTom]

The OP would do himself (and others) a favor by not posting the same question in several different Klipsch forums.

It becomes to difficult to see "who has said what". I won't bother.

 

[yamahaSHO]

CT-120's will extend the frequency.  That said, in your position, I'd just keep the Heresy's and get a sub. 

[OO1]

On 12/19/2020 at 4:49 PM, Westeagle said:

 

 

My question to the community is: do these really cut off at 16kHz, and if so, are there any 3rd party replacements for the k-77 tweeters that go up to 20kHz that would be recommended?

 

 

the K77 can reach 16-17khz with original EV  diaphragms -  the k77 is unique , by the way it sounds ,

 

[yamahaSHO]

For reference, the Crites CT-120 use the B&C DE-120, but with a horn to make it work. 

[garyrc]

I like the K77 tweeter in the Cornwall I, and elsewhere, such as in my Klipschorns. 

 

I have both Khorns with K-77s, and Heresy IIs like yours.  Neither sounds better in the tweeter range to me, both now, and back when I could hear 20K Hz.

 

The K77s sound rich, clean and detailed.  Several writing here like the Crites version better, but a few don't.

 

Frequency response probably isn't as important as distortion levels, within reason.  Distortion figures are rarely published.  Klipschorns (with K77) typically have very low distortion.   Direct comparisons are difficult to come by; most (including the following) are what statisticians call "free floating."  But here are some figures at very high volume -- 105 dB at ~14 feet, THX full scale (fs) for the loudest peaks for sound higher in pitch than 80 Hz.  2% was taken to be the level at which the distortion is becoming audible.

Speakers	IM distortion at 105 dB at ~ 14' (fs)	Harmonic distortion at 105dB at ~ 14' (fs)
Klipschorn	2.00% Becoming Audible	0.25%
AR 4-way AR 98RS	2.7%  Audible	~3% Audible
Fried Studio 4	10% Audible & Annoying	4%  Audible
Platinum Studio 2	7% Audible and Annoying	1.9% Becoming  Audible
From reviews by Heyser, Keele, Jr., and others.		..

           

 

In looking at K77 curves, you will probably be looking at Electrovoice T 35 curves, because the K77s are highly selected T35s.

Klipsch would order a bunch of T35s, and run curves and other measurements on them, and keep the best to become K77s, and send the rest back to EV.  So, the K77s should be the cream of the crop.

 

Here are some K77 curves.  I believe a Cornwall I crosses over into the tweeter at 6K Hz, so the graph is of interest around there and above.  The red curve is a K77 that came out of a Klipschorn.  They were plotted at different levels only to allow you to read them clearly.

Here is one I ran, with 1/3 octave smoothing.  In case you can't see it well enough, it crosses the line at 12.44 KHz, and ends at 17K (the 1 in the numeral 17 is cut off), down about 4 dB.

 

Hear is a histogram of a KEF studio monitor.  KEF is one of the most respected speaker makers.   !5K here is down about 5 dB. See what happens when it hits just about 16K:

Now, here is what may happen when you get into a room -- just in the bass--at least they claim this  is typical room response:

 

Here is a full range example  with studio monitors in a presumably a good control room, before treatment, By Jesco in Acoustics insider:

       LEFT                                                                                                        RIGHT

 

Now here are 2 elite loudspeakers, in a listening room, but spatially averaged and with 1/3 octave smoothing. 

Wilson Sophia Series 3, spatially averaged, 1/3-octave response in AD's listening room (red); spatially averaged response of AudioNote AN-E/SPe HE in AD's room (blue). [Stereophile]

 

Let's look at the top end.   The Sophia is down about 5dB at 11K and about 6.5 dB down at 12.5K.  True, it springs back up at about 14K, the is about 5.5 dB down at 15K.  And at the 20 K you wanted?  It's down 28 dB.  This reputed to be one of the  best speakers in the world.  Back then you could have it for about  $17,000 for a pair.   To be fair, many reviewers want the high frequencies to drop at the top of the  treble.  Some get upset if it doesn't, or label the speaker "Bright."  Others advocate the Harman target curve in which the bass is much louder than the treble.  Most slopes I've seen have the loudest bass 9 db louder than the highest treble.  In the one below, as they say, "after equalization" it's more like 10 dB, with 16KHz 15 dB below the loudest bass..

In experiments, listeners tended to think such a curve was FLAT and NATURAL.

 

With my Khorns with the K77, I like the bass about 7 dB higher than the treble, but I usually don't curve the treble down at all.

 

You can use absorbers, diffusers, bass traps, Helmholtz Resonators, electronics, etc. to fix much of this, but then you'd be down the rabbit hole, for sure.

 

[jjptkd]

14 hours ago, Westeagle said:

From what I can gather online, some people say that the tweeter starts to drop off around 16kHz. The Heresy ii's tweeters are very satisfying to me and was wondering if these opinions I have heard about the Cornwalls were accurate? I am fortunate to be able to hear up to 20kHz, so speakers that roll off at 16k don't cut it for me.

 

My question to the community is: do these really cut off at 16kHz, and if so, are there any 3rd party replacements for the k-77 tweeters that go up to 20kHz that would be recommended?

 

Thanks very much!

 

Westeagle

Hello, I wouldn't worry about the tweeter if you've found a decent deal on a pair of Cornwalls go pick them up and try them out for yourself in your own listening space, that is really the only way to tell if you're going to like them or not. As mentioned above Bob Crites has a few different tweeter replacement / upgrade options if you end up finding the tweeters to be lacking. Personally I really like the CT-120, made a really big difference in the Heresy HIP's I had.

 

 

[Westeagle]

Thanks very much for your responses! It's good to hear different perspectives and the fact that there are options out there.

 

H

[mustang_flht]

Your last option is the superb horn small MAHL by Dave A, they are available in aluminum or wood. You can add the driver you like: B&C DE120 / 110/110, Faital Pro HF102, driver 1"... or even change it later if you want, you will be free.

 

 

 

 

 

[ClaudeJ1]

On 12/20/2020 at 7:25 AM, jjptkd said:

Personally I really like the CT-120, made a really big difference in the Heresy HIP's I had.

Agreed. I measured one from @DizRotus

It's good.

[SpeedLimit]

Hello, did you take b&c DE120 in 8 ohms or 16 ohms ?

[OO1]

8 ohms -

[SpeedLimit]

Thank you RandyH000

 

So for my Clone Scala with the AL-3 crossover, if i resume, i need Eminence Kappa 15C woofers (4 ohms), Atlas sound pd-5vh squawkers (16 ohms) and B&C DE120 (8 ohms), is that right ?

[OO1]

43 minutes ago, SpeedLimit said:

 

So for my Clone Scala with the AL-3 crossover, if i resume, i need Eminence Kappa 15C woofers (4 ohms), Atlas sound pd-5vh squawkers (16 ohms) and B&C DE120 (8 ohms), is that right ?

Correct -this is how the AL-3 is designed ,  had you chosen 16 ohms for the tweeters , this would result in a lower current draw to the tweeters- from the network -

[SpeedLimit]

great, thanks for helping me choose the right model, I will order a pair of  DE120 in 8 ohm  (B&C DE120).

[SpeedLimit]

ordered instantly, all I have to do is wait for the package to reach me

[Montego]

On 12/19/2020 at 11:47 PM, garyrc said:

I like the K77 tweeter in the Cornwall I, and elsewhere, such as in my Klipschorns.

 

The K77s sound rich, clean and detailed.  Several writing here like the Crites version better, but a few don't.

 

 

I'm one of the few.  I just returned my 1967 Cornwall II with CT125s and B-2 crossovers to their original configuration.  They sound good both ways but I prefer the k77s.