Volti does it again!

IPC made terrific gear.  In particular, I like their IU 1000 compression driver that has a diaphragm just like a Western Electric 555 diaphragm.  This driver was made in the 1930's and 1940's and I would put it up against any midrange driver made today. 

I don't think that Volti, or any other modern builder has access to compression drivers as good as these old drivers.  The modern ones that sound very good are VERY expensive, such as Goto, ALE and Cogent drivers.  I do think that modern manufacturers can make good horns for their drivers--either new designs or replicas of old horns.  I've heard a few such modern horns.  Volti appears to be quite successful with making practical horns that can be fitted into reasonably sized cabinets.  Still, there is something about the "weight" and sense of authority of a larger format horn that makes one dream of owning such systems and the room that can fit those monsters.

I run a smaller vintage horn (KS12025) which is a two-foot wide by 6-inches tall metal sectoral horn.  It is a straight horn which makes it too big to fit into a practical cabinet (it sits on top of the woofer cabinet).  My compression drivers are Western Electric 713b's.  The sound is quite good and is free from excessive horn coloration, but, when this driver is put on large format horns, it is evident that size does matter in horn-based sound.  I don't have the room or the money to even think of an upgrade.  That has left me with upgrading the crossover which I am in the process of doing.  

Please understand that these are just my own thoughts on this subject. It’s not like I was tutored by the man himself about this. But based on my experience in designing and building midrange horns, here’s my thoughts on the Klipsch K400 horn used in the La Scala and Klipschorn loudspeakers.

In the beginning, Mr. Klipsch had a terrific folded horn design (Khorn). Compact and fitted in the corners of just the right sized/proportioned room, these bass horns produce solid bass down into the low 30’s and have a way of surrounding the room with bass that I’ve not heard from any other speaker. The Khorn bass horn cuts off naturally at about 400hz on the upper end, no crossover needed. Mr. Klipsch needed a midrange horn/driver combination that could reach down to 400hz to integrate with the bass horn. He chose a midrange horn size that would fit comfortably under the tophat design of the Khorn and then manipulated the design to lower the Fc of the horn by lengthening the throat of the horn, creating a long, narrow pathway for about half of the length of the horn. It is obvious to me that the unusually elongated throat of the K400 is ’pushing’ the horn beyond it’s ’comfort zone’ and causing the characteristic honky, colored, and harsh sound that the horn is known for. But it does reach down to 400Hz! The goal was met, but at a cost.

Twenty years ago or so, someone was building midrange replacement horns for La Scala and Khorns that had the same mouth size/shape to be a direct replacement. The horn was much shorter though. Still with a 1" throat, but not elongated. I tested and listened to a pair of these in my Khorns, and indeed they did sound less colored and harsh than the stock K400 horns. However, there was a problem. They didn’t extend down to 400Hz, leaving a ’hole’ in the response between the mid and the folded bass horn. Could be overcome somewhat in La Scalas, which have bass horns that can extend up higher than 400Hz to meet the midhorn with the higher Fc, but no chance with the Khorns. This exercise demonstrated to me how Mr. Klipsch took a ’normal’ exponential horn design and lengthened the throat to lower Fc. The replacement mid horn with a shorter/normal throat would get down to 600Hz and the longer throat K400 down to 400Hz - but at the cost of sound quality.

Nowadays, modern compression drivers are much more capable than they ever were. Machining tolerances, modern materials, and modern manufacturing processes enable compression drivers to produce lower mid frequencies with very low distortion. A modern compression driver with a 2" outlet and 3-1/2" diaphragm feeding into a 2" throat horn is capable of covering low-mid frequencies in a typical listening room with much greater ease. It is no longer necessary to push the design Fc of a horn by constricting the throat. A shallower design with a 2" throat that fits under the tophat of the Khorn can cover down to 400Hz with ease, and with no unwanted colorations, glare, or harshness that plague older and lesser quality designs. Think of it this way, the modern compression driver can cover more of the load, not requiring the horn to do as much.

Why does Klipsch still use the K400 horn in their speakers? It really is one of the worst sounding midrange horns ever produced. I just did the demo today for a customer who visited here to listen to my speakers. I spoke through the K400 and then spoke through my V-Trac horn. The difference is night and day. Charlie left here today with a pair of Lucera speakers in the back of his van and a big smile on his face. The demo of how different horns can sound I’m sure had a little to do with that. It certainly didn’t hurt.

So why? Perhaps it is because the Khorn has an iconic sound that Klipsch simply cannot change. People are used to a certain sound from the Khorn. Making a big change to the sound would be kinda like making Wonder Bread into a healthy slice of bread that you can no longer squeeze into a little ball in your hand. lol. Is Wonder Bread still made? Or how about New Coke? Remember that one? How did that go over?

I don’t know, it’s a theory.

Greg

You pose a very good question and point Greg. For instance the pizza I grew up on in my side of town is known to be not that popular among people who claim to know better, or “Foodies”… but for me, it’s a must have once a week. Many others too as the pizzeria always seems to be busy. The same could be true for what people want in a sound signature, or aesthetic. What we’re used to, we grew up with. Or what was an important sound experience in our lives. For instance when I open a new record I get a slight smell that takes me back to opening my dads record cabinet.. 

Hey Folks,

Quick story of a visit to Volti Audio.  Before Greg moved to Tennessee from Maine and a week before his visit to our brother, Art Dudley's (RIP) home in New York, a friend and I demoed his Vittoras for a friend in CA.  Jeremy had fallen in love with the fine woodwork at a show.  Greg had graciously set up the threesome on the long wall of his "Paul Klipsch dimensioned" living room space.  At that time, I was unaccustomed to larger spaces and horns in general.  Greg said he had vacillated in using the short or long wall.  He was still locking in the crossovers, driving the pair with less than 2 watts of tube power, a Canadian amp designed for him.  I had brought a small batch of CDs and we settled in. 

The glory of a full range horns was fully in evidence.  Since then, I have experienced 10 years of sharing a huge space with a nearby friend, sampling modded corner Tannoys...in nearfield, vintage AR9s, King stats, Dynaudio, Von Schweikert, others.  I've forgotten Greg's CD player, but it was one of the day's best.  The musicality of the digital source shone through, yet lacking some detail, especially by today's standards.  My flavors focus on truth of timbre and a detailed soundstage.  I suspect the short wall would have increased and enlivened detail, we agreed.   

Greg tossed in some rock and cranked that little SET amp with a shrewd grin.  I was looking for the exits...NOT because of distortion, rather, sheer clean, powerful volume.  He had the Vittora's 18" sub locked-in and man!  Winning the day were cuts from "Let Your Voice be Heard," Cantus, a men's choral group recording by Phile's former Chief Editor, John Atkinson.  The space of that college hall is captured, and the sound spread, glorious!

Art Dudley, to me so qualified in many ways...great ear, musician, hands-on turntables & loudspeakers, likely THE best audio story writer and plain-truth evaluator ever, found the Vittoras a bargain.  (for me, TAS's HP paved the way in DESCRIBING SOUND.)  Imagine if Art had allowed himself the luxury of room tuning!  I respect his choice of an untreated room for reviewing but am somewhat saddened he didn't get to live with a well-tuned room at home.  Today, one wonders of his thoughts surrounding the BACCH crosstalk-cancelling DSP?  I've had the Plug-In since last August and cannot find a negative.  Yes, it changes lots of overdone studio stuff, however, who's to say what is better around that?  On minimalistic recordings, for me, truth of timbre increases atop the spacial stuff.  The future.  

I found Greg to be a no-nonsense, fair-minded businessman with a great passion for his craft and love of music.  An artisan.  His sincerity and directness brought back the days when a handshake was enough.  Greg, if you chance onto this, thank you again for a memorable experience.  Continued great success to you and your wife and your lifestyle choices.  Tim G

More Peace, Pinthrift                   (bold print for old eyes)