Cornwall conundrum

[hamonrye]

I have been lurking for some time, hoping to find some information about upgrading my Cornwalls. Not much new has shown up.

I love the midbass to midrange dynamics they provide, but simply find that they need to have the midrange better integrated (padded down) to the tweeter, never mind the severe roll-off below 63hz ( I thought they were supposed to be rated to 1db- at 38hz ?)

My problem is that it appears that the only mods metioned here are the ALK crossover, and the Pro sound mid horn.

I am sure that the ALK Xover is well designed, but it turns the Cornwall into a 4 ohm speaker, and I am a devout SET user. SET's do not want to see such a dificult load (imp). Sounds like PP, SS territory. In fact I noticed most posters use Japanese SS receivers.

I have been told:

1) There are no better tweeter drivers available to increase high end frequency response?

2) That using an L-pad is the best way to integrate the midrange driver to the rest of the system

3) The tractrix horn has no bearing upon the poorly integrated mid-to-high region

4) To ignore the bass limitations.

Any comments on the above issues?

Feel free to send any info you have to my address.

Although I am about to sell them, I could still be nudged back into the fold.

kt66@teleport.com

Kevin

[mobile homeless]

Hmmm... This makes me wonder what your room is like, and what your source, amplification, and wire choices are currently. Also, which Cornwall?

I am running a Linn LP-12, Rega Planet, Cary SLP-70 modified preamp, Welborne Labs 2A3 Moondog Monos (3.25wpc), and 1977 Cornwall I with Alnico for mid and tweeter horns. For wire, I am using www.DIYCable.com Superlatve, Fat Ones, and Twisted Cross Connect for speaker wire.

I am getting EXTREMELY good low end down into the 30s as claimed (I am in a rather medium sized to small room) with very sweet, clear, and open highs that are not rolled off but very musically natural and true to the source. The Cornwalls easily displaced my previous favorite ProAc speakers putting them to second system status in a matter of minutes.

If your Cornwalls have the original Type B crossover that is VERY simple with two vintage oil caps I think going to the ALK would be a mistake. I happen to think the Type B are very, very musical and natural sounding and a perfect match with the wire and sources I am running. I think the Alnico are nice as well.

So, what year is your Cornwall? What is your room like?The rest of your system? And what are your musical tastes?

kh

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s y s t e m

Linn LP-12/Linn Basic Plus/Sumiko Blue Point

Rega Planet

Cary Audio SLP-70 w/Phono Modified

Creek OBH-12 Passive Preamp

Welborne Labs 2A3 Moondog Monoblocks

DIYCable Wire - Various

1977 Klipsch Cornwall I

Alternate Components:

EICO HF-81 - btw, perfect Cornwall match

ASUSA A-4 EL-34 UL

ProAc Mini-Towers

EICO HFT-90 Tube FM Tuner

Sumo Aurora Tuner

Nakamichi CR-7af>s>

[Klipschguy]

I don't hear what your hearing with my Cornwalls. Homeless mentioned something about your room configuration. I too, am curious. By far the best tweak you can do for Cornwalls is having them properly set up in your room. Deep in the corners will definitely help with the bass. In my huge room, I am getting useful output at 30 Hz. You can definitely feel the bass (tone controls defeated).

As far as the midrange is concerned, you could mess with the T2A autoformer taps and capacitors to change the relative outputs of the horns, but you need to be careful. (I'm not necessarily recommending this, just throwing it out there.)

Cornwalls are midrange foward (like all the big Klipsch), but this is something I personally love about them. I went through a lot of speakers before I arrived at my Cornwalls. They have the sound I was searching for. It may be time to expand your search and try some different speakers. Horns, I'm sad to say, are not for everyone.

No matter how many tweaks you do, a Cornwall is still going to sound basically like a Cornwall.

One last thing, try different amplification to make sure your dislike is not coming from your SET's. Just like horns, SET's are not for everyone (just a suggestion, I am NOT putting down SET's)

Hope you figure it out,

Andy

This message has been edited by Klipschguy on 12-14-2001 at 12:47 PM

[TBrennan]

Ham--IMO the biggest problem with CWs, and the Heritages in general, is the narrow directivity, in certain situations this lends a "fierceness" to the sound on axis. When I did the pro tractrix mod the sound was better dispersed and "mellower" on axis. Now that tractrix mid horn from the KP-301 only has a 60 degree pattern and 90 degrees is claimed for the K-600, the stock horn, I don't believe it. I have 90 degree Altec horns and believe me, they spread much wider than K-600s. Years ago I improved the sound of LaScalas by substituting wide pattern EV SM-120As for the K-400s. Anyway the cheapest and easiest thing to do would be to wire in an L-pad, I think the K-55 is a 16 ohm driver, MCM has 16 ohm L-pads. with the L-pad you;ll find out quickly if it's a simple midrange balance thing. There are certainly more extended horn tweeters than the EV T-35 used, the EV T-350 for one. There are others; various JBLs, Beymas, TADs, PAudios...I doubt anyone has heard them all. If you give-up on the Cornwalls and want a really well integrated 15" woofered-horn treble speaker with deep bass get a set of Altec 605 DuPlexes, those are what I traded my Cornwalls for, no contest. 605s are just as efficient, go deeper and have more punch too, are much smoother with no loss in clarity, I mean smooooth, a VERY refined speaker. Click on the little house to see my webpage with photos and an explanation of the Cornwall-tractrix mod.

[Stu Pidass]

I just have to pipe in here. I'll do you a big favor and take those big old horns off your hands. Just kidding. You'll be hard pressed to find a better sounding speaker anywhere near it's price. Like all vintage horns, these babies are unapologetically accurate. The basic "garbage in garbage out" is true for Cornwalls. Firstly they need to be driven by amplification that's a good match. Do a search on the BB and you'll find a wealth of previous discussion on this.

Another very big and often overlooked thing is speaker placement. As noted above corner placement will increase bass, however, it's been my experience that this comes at the expense of imaging and depth of soundstage. I prefer mine in from the corners and away from the back wall. They should not be closer to each other than the listener is from the midpoint between them. For example; if the speakers are 10 feet apart, the listener should be more than 10 feet from the midpoint between the two speakers. This will give you th ebest possible soundstage and imaging.

There are modifications you can do that are relatively easy, very cheap and are reversible. Wrapping the mid and tweeter with rope caulk is a favorite trick and also replacing the caps is another. I personally would not recommend messing with the crossover and definitely would not swap any drivers. I did, however come accross an interesting tid bit from another post. Sounds like it might be just what you need to tighten up and boost that bass. Here it is as follows:

"15 years ago the Cornwall still had screw terminals on the back.The entire speaker is wired with lampwire. I would recommend you cut off all the spade terminals that hook on to the crossover network. Strip them back 1/2" and tin. Bend this into a hook and then screw back onto the crossover. The problem is most likely in the ring terminals on the inside back of the speaker. Remove the two screws going through the back panel. Go to a hardware store and buy the same screw in brass. Scuff the head of the brass screw with a file.Tin it with solder. Do not tin the threads.Screw the tinned brass screw through the back panel into the input terminal.Cut off the ring terminals from the wire that goes from the back to the crossover network. Strip and tin it. Solder it to the heads of the brass screws. The impedance of a Cornwall is over 50 ohms in the midrange and most of the high end. A couple of ohms resistance from an oxidized screw and ring terminal will not be noticed here. The DCR of the woofer is around 3.5 ohms, a couple of ohms in series with this will cause a severe loss of bass. There is one other thing that could cause a loss of bass but this fix must be tried first. On an inflamatory note(putting out fire with gasoline): when you re-wire one of these speakers with 'monster' type cable 95% of the improvement in sound is due to the elimination of these bad connections."

[Colin]

I have the B-2 network on my 1982 Cornwall 1s and failing to get the ALK crossovers, I am currently playing with an inexpensive Equalizer with minor adjustments. This consists of a 12-dB cut at five kHz to tame harshness that supposedly comes from bounce-back of the crossover network. Actual in-room frequency response at my listening spot is very flat - within three dB from 50 to 10 kHz. This is where most of music is located on the frequency scale. A good portion of the music is handled by the mid-range horn. This sounds crisp and clear. There is also 3-dB dip at 800 Hz and a 3-dB peak at two kHz.

With a 12-dB boost at 30 kHz, my sub-woofers can reach a theoretically ideal response down to 25 Hz at normal listening volumes. But this, by the way, does not sound very good in practice. The bass is heard through out the house. A 12-dB boost at 16 Hz, the limits of the EQ, does little to greatly improve things, either imaging or cymbals.

I am looking at the ALK crossover as one of my next moves, but so far, I am happy with the EQ fix. One thing to note about the ALK though, is that they make the impedance curve very flat. This makes them an easy load to drive. I spoke to Al sometime ago about such low impedance rates and he said this would not be a problem for my 2A3 Paramours (there are lots of reasons why tube amps rated far below SS ones can drive the same speakers).

Since that time, I have learned that the range and sharpness of the impedance curve presents a difficult load to the amplifier, not just the level. This is one of the reasons why Krell's burly power amplifiers are so good at intimidating the independance of B&W's tough bass woofers. Although mobile and I would love to have a 16-ohm nominal impedance for our flea-powered amps to drive, my layman's understanding is that if the impedance curve is full of sharp spikes, not a slow hill, it may still present a "difficult" load for the amps.

Speakers like Coincident in Canada, by the way, are made for tube lovers with their high and flat 16-ohm impedance structure. I didn't look them up, but I believe Dunlavy speakers are also renown for their extremely flat frequency response along with very flat impedance.

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Cornwall 1s & Klispch subs; lights out & tubes glowing!

[WMcD]

Assuming Al's crossovers present a lower impedance, does your SET not have a 4 ohm tap?

Gil

[hamonrye]

You have reinforced my preference for this site. I appreciate all the info. I will fill in the blanks as requested. BTW, I do not for a minute doubt the high quality and design integrity of the ALK xovers, I am merely fishing for other ideas.

Gear:

VPI MarkIII table, audioquest arm, Grado Sonata cart

Modded Adcom GDA600 dac

Wadia WT3200 CD transport

Sansui TU9900 tuner

Heavily modded Quicksilver Audio preamp

Homebrewed 300B amps- triode connected,choke loaded,battery biased WE436a into (RC) 300B, to Audio Note outputs (for you tube rolling nuts like me)

Cables-mix of Cardas, Wireworld, and homebrewed digital

Alternate gear: B&W P-6 speakers, old Revox SS recording amp used as a headphone amp and backup test amp because of highish power, push-pull design.

I am using the Cornwalls in a somewhat restricted space, about the size of an average dining room. I have always been suspicious of bass problems with these room dimensions, considering the long wavelengths associated with frequencies much below 60 cycles.In fact, the most likely reason I may consider selling them. I can't change the room's dimensions.

Let us forget my bass issues for now.

I still wonder if I should be exploring such simple experiments such as L-pads, autotransformer tap dancing, or making my own autoxformers. I understand that the secondaries of output transformers can be used for just such experiments.

Anyway, you all have provided me with some ideas I will follow up on. Hell I may even get out the saw and put in the tractrix horn, and relocate the tweeters; vertical of course.

I really like the dynamics and effortless presentation of these horns. After looking over prices of old Altec,JBL, and TAD gear, this is as much horn as I am willing to pay for.

Thanks,

Hamonrye

[mobile homeless]

Colin, I know you aint listening here cause I've said this more than a few times...but have you thought of getting the original Type B network instead of the $500 ALKs? I see this on eBay every now and then and in my opinion, this would actually be a more musical move over the ALK. Based on shared information with people who's ears I trust, in addition to my own findings, I think the original oil capped, simple Type B would provide a cheaper and better alternative.

You are right about the benign load being a far more appealing load for SET amps. It's the dips and drops in impedance that does wrecks havoc on low watt tube amps, especially if the dip is in the bass.

I have heard a few of the cone driver offerings such as the Silverline Sonatas which offer a very easy load and are around 95dB sensitive. Personally, I thought the Cornwalls were a step up from the $6000 Silverlines which have gotten tremendous accolades. In essence, the Cornwall 1 with Type B crossover was the more natural sounding device; it definitely had more soul.

I dont have a single mod on my 77 Cornwalls, yet I am getting NO bright, harsh, highs or fatiguing, aggressive sound. I think your solution, thank goodness, will lie outside the equalizer. The less you can add to the signal, the better. Take a look around and see if you might find the Type B to give a try. I think the cost would be dirt cheap! What is your preamp again?

kh

ps - Wish I could talk you into some wire...

This message has been edited by mobile homeless on 12-15-2001 at 08:39 AM