R,

Little suggestion should all else fail - you could have a rudimentary phase plug machined that would give you the same (or similar) compression ratio as the original but only one annular exit path. This might preserve the driver characteristics at LF but attenuate HF.

Just a thought...

Following this with great interest in any case!

Cheers,
cv

cv wrote:

Little suggestion should all else fail - you could have a rudimentary phase plug machined that would give you the same (or similar) compression ratio as the original but only one annular exit path. This might preserve the driver characteristics at LF but attenuate HF.

Well, I loved, loved it loved it… but today I decided to experiment with integration the new horn into the system and learned that it would be far much complicated and take more efforts. Below are 3 sweeps form listening position, Firs is the new horn alone with 18.3uF and 3mH coil.  Second is my Macondo alone. The third is Macondo and the new driver work together. 

I have spent an hour (uselessly it takes for me minutes or even seconds) to listening quite completed material and frankly speaking I hate what I heard. I did some adjustments but the pure Macondo allays was more interesting. The new horn added some heaviness in sound.  I was driving the volume of new channels down but even at minus 12dB (!!!) is feel that the new channel brings the elegance and chick if the Macondo upper bass and lower midrange down. Yes, sure the new channel creates a coupe dbs bulge at “heaviness zone”. However if I create the same bulge by my Macondo the upper bass channel than the bulge doe not bother me at all and practically not auditable.

The concussion is that most likely I need to roll off my upper bass sooner and sharper, reducing the penetration of the upper bass channel into the lower midrange channel. Also I have learned that the new channel much be ~ minus 6dB relative to the MF channels as if not then  it does move the image up. I was playing Carlo Maria Giulini magnificent performance of Brahms 4th (nope, not with Chicago but with… Wiener in 1989, good luck to find it!). What could be more strings devastating then the late Brahms? The recording is compressed and quite “flat”. The Macondo with new driver converted it into such a horrendous mess that it would be shame to name. Ironically Macondo without the new channel or … the new channel along played the recording way better. The same is with my beloved Cello and Piano sonata by George Walker – with the new driver it was laughably poor until I was driving the new channel at minus 18dB (!)

What it boils down so far that it would requires much more precision to set the arrangement with new horns to operate properly, however I do not know if I get any benefits then. Defiantly I will continue to play with it and hopefully I will find some kind of wining setting but so far the result is not worthy.

Rgs,
Romy the caT

I spend quite a few hours playing with the new channel trying to ingrate into Macondo but so far not successful.

Since the new channel and the Macondo upperbass horn have identical sensitively and identical impedance I figured that I would drive it from the same amplifier for a time being and now the new channel uses the same Super Melquiades upper bass amplifier and the upperbass horn. The crossovering is very elegant. The amplifier produces now from 50Hz to 800Hz, first order. The upperbass hors kicks-in with no filters at 100Hz and begin to roll off at 800Hz die to the amps roll off. The new channel is in parallel and sites behind one high-pass cap, picking up from ~600Hz -700Hz and dies out at ~1200Hz, since it works after 800Hz along with upperbass horn and gain 3dB. The response is fairly smooth and everything is very “cool”. What is not cool that it sounds like crap!

First thing first: the new channel honks. It does not honk when it runs stand alone, at least I was not able to detect it, but being incorporated into Macondo it screw up sound with ordinary old fashion, disgusting honk. There are many reasons of horns honking but usually it happens due to use of excessively low crossover point. I was lifting up the crossover to 1250Hz and it kills the honk but at the same time it killed the purpose of this horn. The only solution that I see in here is going for second order 500Hz -800Hz. It is what I will be trying next.

The second thing is an absolute mystic to me. The upperbass channel and the new channel crossed at 1000Hz do not sum but subtract amplitude at the listing position. Of could they are in-phase, and I checked it 32309756 times. But my RTA shows absolutely unambiguous that if the channels in-phase then the amplitude tanks but if I put the channels out-of-phase then I gain 3dB at crossover point, as I should in-phase. I have absolutely no explanation at this pint why it is so.

To be continuing…
Romy the caT

cv wrote:

That upper rolloff in the OPT comes from a number of distributed capacitances and leakage inductances in the transformer - it will not be a simple filter. Lots of transformers have weird resonances up at the top of their range. In fact, some makers rely on a resonance to push up the bandwidth. Otherwise, I vaguely recall that a well behaved transformer has a second order rolloff up top. Ie it's a very complex low pass filter with less predictable phsae shift. That's one guess for why the channels are not summing as you'd expect. I would think that relying on the OPT rolloff would be detrimental to sound. The load presented to the tube up there is going to be extremely reactive and screwy.

E-v-e-n-t-u-a-l-l-y!!! Eventually the new “fundamentals channel” horn sounds as it should being incorporated in my Macondo!  The key was the  second order. I really never drove compression drivers to their 500Hz as I always used upperbass horns that give me quite a luxury to utilize MF drivers in very sparing mode, using shorter MF horns with wider dissipation and less beaming. I was always suspect that the folks who use 500Hz 6dB/octave crossovers in typical the 330horn is horno-BS. Now I concluded that, at least with S2, and use 250Hz horn I can not go lover then 1350Hz…. Not god for my objectives to us the “fundamentals channel”

I put today second order into the game to lover the crossover point. The lover I able to go was ~500Hz arithmetically. I did not have correct values and the filter turned out to be something between Bessel and Butterworth. The response got was following:

The sound of the complete systems with the new hors? Absolutely wonderful – something that I, in a special way, was targeting and hoping. The transients at lover mid range become faster, somewhat “crisper” and more coherent but at the same time did not loose their “harmonic puffiness” (I will look it this further though). The lower MF got filed with very noble, typical for the Vitavox S2, tonal nuances with very high tonal contrast. Actually the entire sound became more transiently-realistic andmove even – very pleasant and very hoped feeling.

The honk? Not there anymore, although I still will raise the crossover point to >-500Hz. I am listening now the things that destroy practically any horn installation if any, even remote. signs of honk is hiding in a system: the contralto singers. The Marian Anderson’s Schubert and Ewa Podlles’ Tchaikovsky, Stravinsky and Mussorgsky - what would be more complex for the lover midrange and upperbass? The Podlles’ “Songs and Dances of Death” really got me and ....it is after hearing is many-many times…

I think that this “transient evenness” makes the total dynamic to perceive as slightly higher. I do not know why but it sounds this way, or perhaps today electricity is better tonight. Anyhow, it was the very first very positive result and I will capitalize on it. I did not asses imaging and many other factors but for a time being I’m ordering the coils for a perfect Bessel curve (will measure the impedance at the band-pass frequency) and will fine-tine the new drivers at 600Hz, second order. I begin to be very optimistic about the new horn…

Rgs,
Romy the caT

Yes. I’m exiting to see how the new horn I shaping up. Still I do not think that it is about second orders.  Obviously in context of 5 channels system, the more channels one gets then less room between them. I still feel that in order to do it correct my new channel should be no 250Hz but I would say 180Hz-150Hz and then I would still try to for a first order at 750Hz. In the barrow bandwidth satiation as I needed to get out of this driver the second order was God sent but at think point I do not know what kind negative manifestation it would have on overall system presentation. I will be able to see it when I put the second channel in use and tune the crossover more precisely.

I went for Bessel Q, 600Hz. Since I have no sensitivity burn I’m searching now for the series air-core coil with DCR of around <0.05R and 8-6ga wires.

The Vitavox barbarianism?  Yes, I know the CN458 schematic, opened it up as studied what they were trying to do.  I do not think that it is about barbarianism but about the typical for vintage solution luck of precision, accuracy and exactness. The imaging demands that Vitavox System CN191 had were very restricted, as any other corner loaded system. Also, did you have change to measure a properly installed CN191? I did. I do not have the file now handy but I remember that each channel (!!!) did something like this:

Sure, the decision to go for second order in their 330Hz horn was correct but was in beneficial? I do not think so. 

Still, generally the compression drivers that run all the way down and crossed at 500Hz never use first order; at least I did not see it. As I told above I never used drivers at 500Hz and now I see why people go for second order in this situation. Interesting that Vitavox when for 500Hz 12dB per octave for thier 330Hz but I do not feel that it is a “secure” cut off and I went for 600Hz 12dB per octave for 250Hz horn… I feel that ~700Hz of their RH330 would be more suitable cut off.

The Cat

Did today some critical listing. It is getting along very well. I would need some final adjustments of channels sensitivity (or tine the 6C33C)  and will wrap it up. I will post some general observations later on but for now there are a few sweeps.

caT wrote:

Adding 1uf more and the horn being to sound like Altec horns…

hagtech wrote:

Interesting.  I'm wondering here if this is the key to eliminating the honkiness I hear in most horn installations.  From your experiments, it seems that the low frequency extension is key.  Push it too far and it honks.  Is that correct?

Oh, yes, sure. In 80% of all cases people try to push out more LF out of their MF hours. An extra 20-30Hz threw a horn into honk and you are done.  Particular it is applicable with light rectangular horns, typical for Altec-JBL-Klipsh-Votavox. The typical rule of sum that a crossover should be one full octave above the horn’s cut off. However, from there is it necessary to look further as frequency at which horn honk has to do with other aspects as well: ugliness of profile, imperfections of expansion, type and quality of cone damping, absolute frequency, amont of front chamber compression relatuve to the air-mass of horn, relative mass of horn to the horn rate and few others...

hagtech wrote:

My guess is that folks often do the math for cutoff frequency and then run the horn too close to that point, or worse, include it in the transition (handoff) to the next driver down.

hagtech wrote:

I'm sure everyone here realizes the lower cutoff of a horn is quite abrupt.  I'm not sure what function it is, but the slope is steep.  That should correspond to some nasty phase shifts.  Maybe this is very simple.  Push the thing too far and it will honk.  Treat it with some respect and don't ask to much, it can sing.

1) Own roll off of the horn mouth
2) Second order filet kicks in
3) Own roll off of the driver

Rgs,
Romy the Cat

Got today the parts and finalized the “perfect” Bessel passive crossover for my new channel. The coils are regular air-core 2.5H and 7H, the caps are Theta 10uF and the small wirewound tuning resistors that kills ~1.5dB in the channel. When I put all together everything came together. What the beautiful result!!! The most wonderful in it this, beside the sound itself, is that by tuning the resistor -/+ 1 dB it is possible very precisely dial-in the weight of the MF balance and it affects presentation very-very-very interestingly. My initial intention was to put there a small L-pad but then I realized that after a couple days of listening and finding the correct balance I would not need it any adjustability in there anymore. I think it will be something between 1Ohm and 2Ohm dropping resistor before the first coils.

Sometimes what I have time and intention I will try to drive the thing with own amp and a line lever filters…

But for now, the chanall and the Macondo do very excellent, they well fulfills my expectations and I’ very happy Cat.

After the painstaking setting up of the new Macondo, measuring all distance, paralleling the horns and time-aligning everything, after the setting up a correct level of the new channel’s attenuation (it turned out -2dB was necessary) I spent some time to listing the altered Macondo.

The red thread is the diaphragm’s line of all channels. The extension of the top section of the woofer tower made intentionally to EQ the arriving tome to the listening position that is located much lower

The conclusion is very firm: the new channel will stay, permanently. The benefits of it are numerous and I would mention for a time being juts one of them: the tone. Audio people practically do not talk about tone, or something that I call “absolute tone” on context of audio playback. They do not do it because “absolute tone” is not a manageable properly in their intentions. Audio people (best of them) recognize “tone” as the property of recordings but they very rarely think of playback as something that might do discrimination of tone.  The various amplitude deviations of playbacks affect tonal characteristics of installations but when I talk about “absolute tone” I mean something very different just “tone”:

http://www.goodsoundclub.com/TreeItem.aspx?PostID=1249

The “absolute tone” is the absolute maximum of tonal complexity that a playback is capable to reproduces. It is like a violin. If we take for instance Amatis, Stradivaris or Guarneris then they might indicate a quality of “absolute tone”. It does not necessary mean that they under all conditions have better tone than some other best violins but under good conditions they are capabe to throw insultingly high (or interesting) tonal quality that might not be reached by “other” violins (particularly in ambient conditions). This absolute maximin amplitude of the “tonal sophistication” is not reachable by some "other" instruments, no mater what you do to them and how skillful players might be. The very same is with loudspeakers. They all have their “absolute tone” limitations. The audio people mostly do not consider them because the 99% of loudspeakers are “absolute tone” impotent. We do not really know where the “absolute tone capacity” derives from and audio engineers never cared to answer this question. Perhaps it is in materials or in design principles but I feel it rather in a sense of recognition and assessing of results – something that never was research seriously in audio.

Any discovery of audio elements that are capable for a higher degree of “absolute tone” is always accidental. Generally, some older drivers form 40s-50s: Altec, JBL, Western Electric, Klangfilm, Vitavox, Telefunken and few others had higher degree of “absolute tone” capacities but they all were horrible from other perspectives. The art of building Macondo, as any other acoustic systems that are “absolute tone minded” was to recognize and to embrace the best that those drivers can so but at the same time to make them to work in a totally unknown to them level of “precision” and in context of the more advanced and more demanding contemporary home-based horn system.  I stuck with Vitavox S2 driver exactly and only because it’s unreachable by any other known to me compression drivers “absolute tone”. Do not get me wrong. The Vitavox S2 is as crappy as any other vintage pro driver but I am dealing with it for a long time and I have learned how to treat it in order to get from it any more or less civilized sound. I feel that I had very-very serious “absolute tone” capacity in Macondo before the new channel was introduced. I think anyone who spend time, effort and common sense with many other best compression drivers might get good result out of them but it is imposable to jump of own head and any driver has own limits of “absolute tone”. I heard a lot of the best loudspeaker and I did not see many of them, if any, take “absolute tone” as far as Vitavoxed Macondo could (if electricity is good- the constant bitch of “absolute tone”). Partially it is difficult to fight with “absolute tone” at higher level of sensitivity where everything becomes much more complex.

The former version 4-ways Macondo was very good and did “absolute tone” at very-very serious level. It might sound like I’m juts a next typical Morons who just run my mouth about my gear. I would like to believe that it is not the case. For reasonable, not Moronic or interesting people I always was welcomed to put my actions behind my blabbering and actual to demonstrate Macondo sound. I know that some of you folks who visit my site were in my room and heard my inhalation. I hope it was adequate in relation to the verbiage that I express. However, there were always some areas that I would like to have taken further in Macondo. I will name just one of them.

The lower region of the clarinets, flutes, oboes, piccolos, recorders the mid regions of saxophones, bassoons, the entire family of the woodwind instruments and their relationship with “total sound filed” is very complicated subject for sound reproduction. Those sounds have tension; stress and “space” on real world but playback make them flat and un-granular. (The contemporary industry tendency to convert it into a miserable high pitch whistle and if the Morons doe not hear whistling the do not acknowledge “their quietly”). I always was looking for something that I call “frozen day sound” in woodwind instruments but at the same time I would like them to have the “absolute tone” AND be very-very soft (the contemporary drivers could not play “soft” and “crisp” as the same time). The new “upper fundamental channel”  moved the capacity of the “absolute tone” further, helping the “woodwind” problems,  by equalizing the transient evenness of my acoustic space but without violating the “absolute tone” constant. Very positive effect indeed…

http://www.goodsoundclub.com/TreeItem.aspx?postID=2768

I have to note that CDs do not go there where the NEW level of the Macondo’s “absolute tone” lives. Analog does or high sampling rate recordings do. I do not do today’s commercially available SACD (and sincerely feel that the people who do are Morons as they deal with very inferior materials and with very ignorant people). The 24bit is OK and the 88kHz-96kHz would do (I have no means to go for higher sampling rate and I do not know if it would be necessary). Anyhow, in the context of 24/88kHz the “frozen day sound” really blossoms and the New 5-ways Macondo can handle it better then before.

Now, I need a listening room twice larger for the New Macondo:-(

My playback was in “distraction mode” for a few weeks. The electricity is horrible nowadays, summer… The arrival of APS made me to reposition all components disconnect everything and the failure of the APS so far to do what I want it to do did not encouraged me to put all my playback back together. So, all my cap was sitting “as is”, disconnected, and have been listening for the shitty Denon table-radio driving tiny Mission speakers…

Eventually I got sick from it and put today Milq and Macondo back to service. Hm, it looks like the efforts were not as stupid as always assume. Although the electricity is still not good but it is still a different sound all-together…

I got a few new recordings today: the wonderful Japanese pressing of Knappertsbusch’s Bruckner 7 only not with Weiner but with Kolner Rundfunk from 1963. The Bruckner and Macondo is a very different subject, I have feeling that Macondo even made me to “get” Bruckner.  I listened a few other things but what actually was most thrilling experience was Joseph Schmidt album, the opera and operetta fragments. It hardly imaginable that I need all Macondo’s capacity to play recordings from 30s. Think again.

jessie.dazzle wrote:

I really appreciate the result of the 180Hz horn with the S2... Particularly in terms of "texture". It is responsible for such an important range...

Well, if you appreciate the lower knee of the S2 driver then wait unit you hear it’s perfomance with reduced dumping of the cone.

I have been trying to solve the dilemma why my 250Hz Tractrix does not allow itself to be loaded too closer to the horn rate. I was not able to go lower then 600Hz and their order (!!!) and it is not where I would like to be. When I was dropping the crossover point I was loosing the cleanness of S2 tone and it became muddy and nasal. I was and still am planning to do some modifications of the horn; I will post the pictures later on.

However, in addition to it, last nigh I decided to experiment with the damping of the driver’s cone. How pleased I was when with redaction of dumping I got instant improvement in the very direction I would like to have improvement. The channel began to response much lower and the most important the tone (with lower response) become absolutely free from any nasal colorations and from any dynamic congestions. I was listening again and again and was very pleased with the result (I was listening juts one Fundamentals channel).

I did not figure out how much the back chamber should be extended, my preliminary assessments that it should be for my horn made 4 times larger. I am seriously contemplating that if I will be ordering from my machine shop the extended S2 back chamber’s cover then to make it with adjustable volume (proposals are VERY welcome). As you can see on the picture the back plate should have larger (adjustable) chamber….

Well, this post would not be complete if I did not measure the thing, of course I did. I measured the lower knee of the S2 response in the Fundamentals Channel, way off the axis (~45 degree off). The channel is high-pass with one 25uF cap that makes around 400Hz, first order. In this animated image you will see one measurement (closed back) as a default S2 driver and another “with crack”. The crack was make by screwing off the back plate of the S2 drive for 1 turn and introducing (juts from one side) a  little, <1mm  crack between the diaphragm’s plate and the back chamber’s cover.

I really would like the Vitavox users who use the bottom region of S2 driver to pay very serious attention to my post above. The redaction of compression in this driver and dropping the resonance frequencies does impacts the lower knee sound of the driver very interestingly.

I am contemplating to modify or to make a brand new back chamber’s cover for S2 driver. In my new cover I would like to have an opportunity to gradually modify the volume of the back chamber. It would be not difficult to do with the gasket under the chamber’s cover but it would have own limitations (restricted Vmax) and problem with confortability. So I was wondering it I could make something more elegant.

I was thinking to make some kind of valve in the back chamber that would be adjustable from a very minor pressure drifting (.01 sq mm) to a relatively large, practically wide-open hole: 5-7 sq mm. Does anybody with mechanical skills could come up with some kind design ideas?