Back to 2006 I had a thread “Adding one more spherical to Macondo.” The thread itself and the concept that it lead to - the Fundamentals Channel - turned to be a phenomenal success. I know, I know for someone it might appear like nothing but if you do run your playback with a dedicated, active Fundamentals Channel and you have option to dial it precisely to the rest of your Sound then you know the power.

My current Fundamentals Channel is 600 to 1000Hz in 250Hz tractrix driver by Vitavox S3 driver with old metal diaphragm. I however would like to run it from 300-400Hz but ether driver or horn did not allow me. So, I always would like to have larger horn, just a bit sub 200Hz and then to find a driver that would support lower crossover point and will furnish the sound quality that I would accept.

I however can’t not go for larger horn as I do not want to minimize clearness for tweeter and Injective channels. I also would like do not use tractrix for my Fundamentals Channel but to go for exponential profile and to drive it harder down. This all lead me to the idea that I need to go for rectangular profile with fixed height and to add opening on the side. The multi-cell architecture was a logical chose.  A regular 15 cell with my targeted height usually do 230Hz but I have unlimited width. So if I find somebody who can curve the thing to 18 or 21 cell then it might do.

I found a guy in England who agreed to do the 15 cell, 183Hz horn with 1.5” throat. The requirements’ were to have them made from soft wood, fill-able with sand and a few other things. The horns are semi-done, sitting in the room and ready to be tested. 

I am not diving in this project right now as I would like to wait a bit. I would like to beef up those multicells . I would like to think how I would mount it to the Macondo frame, How to finish them. The most important I would like to see if Macondo will be truly beneficial from this type addition: sonically, visually, ets… I never was multicells fun but Fundamentals Channel does not do any HF, so it might work. I initiated this thread and I will with time to post my observations about the use and accommodation of this new multicell. If everything tune well then I will add to Macondo but I at this point not wind about visual aspect.  The   multicells looks too much like loudspeakers. I might cover the multicells mouth with black caustic fabric or perhaps I will get softer on it after I paint them black…. I do not know, let see what will happen.

Romy,

I'm trying to understand your logic in choosing a multi-cell design (instead of a single-cell oval or rectangular 180Hz exponential horn of the same vertical height)... Was this in the interest of achieving a more diffused radiation pattern (less beaming) or possibly a desire to keep horn length short?


jd*

jessie.dazzle wrote:

Romy, I'm trying to understand your logic in choosing a multi-cell design (instead of a single-cell oval or rectangular 180Hz exponential horn of the same vertical height)... Was this in the interest of achieving a more diffused radiation pattern (less beaming) or possibly a desire to keep horn length short?

Oh, well. When I begin this think about the larger Fundamental Channel I was thinking about the rectangular 180Hz exponential horn. They I found a site that give me an idea that other options are possible. Ironically the site that gave me the idea was my own. If you look at home page, at the site center image then you might see a cartoonish of multi-cell horn. The fun part that I very much like the sharp curve of this horn and I thought that I will be able to do the same. I was talking with a few horn makers asking them for 21-23 cell horn that will have 160 degree opening. You the problem is that math to circulate the Multi-cell try assure the right curve of the side cell and as I understand it presume HF radiation. To make the long story short - I made 18 cell as I was not able to find anybody who do semi-omni 23-cell. That would be the lower MF only but people apparently do not get the DSET concept applied to horns.

Yes. The logic with multi-cell was coming from the fact that they would be shorter as I do not want the Fundamental Channel to be excurted too much further. And yes, wider radiation pattern also was my intention in the new room. The new multi-cell made to have 2” less height then my 250 Tractrix as in the spherical horn there are those chords from top and bottom. My initial idea was to have less cell in center – only one row and 2 extra vertical cells from sides – 22-24 cells, or to have sort of narrow middle with two multi-cell budges on the side. I would not able to find anybody who would go for the implementation such an ambition thing. It would be virtually a combination of 2 18-cell and one vertical rectangular combined together per channel. It is possible to build it but it is VERY difficult (if possible) to curves averting into the same 2” throat. It however might be possible if the condition will care only lower MF.

Here I am with my conformist multi-cell, it is not what I would like to but it is what I have. The idea was that if it does not work for Macondo then I will add it to my Altec 19 project. As I said I am not too pleased with visual aspect of the multi-cell. The whole beauty of the spherical shape is that it natural and it does not look like hardware makes efforts to produce sound.  The multi-cell makes hardware too much trying – I do not like it.  Might be I need to see how it works in black or might be I need to mount the multi-cell in place the  Fundamental Channel after I paint them and to see if the multi-cell will feel right. As now, the multi-cell feels like “it is not from there”….

I would not be surprised to learn that the impression of depth from multi-cells is the result of their creating a bit of what has been referred to on this site as the x-factor; a sort of cross-feed/expander effect (see discussion of Lamm preamps and x-factor). In one case we are talking about an electronic amplifier, in the other a physical amplifier. While it may be useful to describe the effect in similar terms, the means by which it is achieved in each case are obviously different.
 
So how might these horns be producing x-factor?
 
My hypothesis:
 
Multi-cell horns take what comes out of the driver and slice it into parts; in this case into 18 parts; each cell then processes a different part of the total; parts taken near the center of the throat are not the same as those taken near the periphery (especially given a throat of rectangular-section). Each part is processed in isolation; meaning in the absence of the total sum, which must be very different from allowing development in the presence of the total. The result is that the 18 parts exit the horn each having different "identities". This might be analogous to quintuplets (18-tuplets?) separated at birth, sent off to different boarding schools, then reunited. Or to a schizophrenic looking out the window. Or to a melting-pot culture as opposed to a society of clones.

Upon exit, the product of each cell, which lack different parts of the total, collides with or overlaps that of neighboring cells, resulting in a sort of fusion that does not occur with single-cell horns. The "offspring" that is the product of this fusion might be "healthy" and interesting.
 
If any of what I'm hypothesizing is valid, a multi-cell, round-section horn having its partitions evenly spaced and radiating from the center, would not produce the effect of depth, as this would result in a "society of clones"; the resulting "offspring" would be analogous to the product of inbreeding. Varying the spacing of the partitions and adding a second tier (a flare within the flare) should result in healthy offspring; the impression of depth.

If a multi-cell horn is analogous to a melting-pot society, a correctly implemented, single-cell horn might be analogous to the complete, right-living man of exceptional integrity (something even more rare than correctly implemented horns). A single, correctly implemented horn will not offer the x-factor of a multi-cell, but an audio system consisting of correctly implemented, single-cell horns should result in its own kind of x-factor.

jd*

My 18-cell is a classic 18-cell very similar of the one that the guy from Sweden built:

http://www.diyaudio.com/forums/multi-way/136964-construction-multicell-horn.html

The difference is that my multicell has 3 extra cells and outer skin that allow the horns to be filled it with sand.  I have some things that I like and do not like in my new horns but the construction of the multicell is pretty much irrelevant for what I care at this time.

 Running my 18-cell full-range with my Vitavox I do see all that I like and do not like with multicells full-range. But as I said above - that “depth” of the multi-dimensionality effect is not something that might is interesting. I think the key of multicell depth are in the fact that multicells acts as error randomizer.  The multicells are not perfect horns - the entrance to the multicell screen from throat is horrible, the individual cells are time misaligned to each other as they are angled, each neighboring cell acts as re-entry hors and many other problems that I might  call. But the nice thing about multicells and only about multicells with many multiple cells is that error of each cell is randomized and as result made undetectable.  As the result think we use with multicell horns the effect similar to the one what we in childhood when we “heard ocean” but closing large seashells to our ears.

One of the ugliest things with multicell is that fact the room is reflected in the horn. If you hear very careful then you can recognize that sound eco itself in multicell. It feels like multicell acts as an array of self-shorted Helmholtz resonators. Some people managed to do it even with a single cell horn (for instance the large conical Congent MF horn at CES had VERY strong this effect for some reasons). The multicell horn has this effect much stronger. However, I think if to recognize this effect and if to control it sensibly and creatively is possible.

So, what multicell my new 18-cell has to do with Macondo? Good question. First of all I would like it to be not 18-cell but 14-cell or 30-cell, the more is better.  The initial idea was to replace my Fundamental Channel with larger with restricted height but as now I can see that this idea will not work. The 183Hz slow opening horn is too long for my current Macondo frame and it will break time alignment among with a few other Macondo things.  It is possible to accommodate this 18-cell with Macondo but it will take to make another frame. I do not want to do it as I do not feel that cost-benefit will be significant.

Experimenting with my multicell I come to a very interesting idea that if I use multicell in HF-restricted more and driver via it only Fundamental Channels spectra then I can set my 18-cell way off the Macondo and try to attack with it the Macondos’ width-modulation.  I have written about it in the following article:

http://www.GoodSoundClub.com/TreeItem.aspx?PostID=15000

So, I think to position the multicell vertically on the outer sides of Macondo and to see if I will be able to convert my 18-cell into with-modulating channel. I would need to assess how it all works all together only what playback works perfectly it means that after my PP2000 come back. I will see if this type of Fundamental Channel offset will be useful. I think it will be but it will be necessary to set the thing up very sensibly. Below is a phonograph of the Macondo rig channel with added width-modulating multicell. The picture is made from the Listening chair and it gives an idea what I am trying to do.  The time will show if it works.

Regarding the drivers. Will see. There are a number of drivers out there that can go for 300Hz or lower but I do not know at this point what kind sound I would like to have from this channel.  It obviously will be some that would go lover then S2/S3 but I do not know how much transients the width modulator will handle. It is possible that the width-modulating multicell will demands a very soft sounding driver, so I will be looking in it with time. For now I need to paint this horn in black as soon as possible….

A few days back a Goto SG-555PS driver pop up for sale in Australia. My idea to try this Goto is because it has diaphragm in front and it would be easy for time-aliment. I was considering getting it but the price was too high for my need. If I know certainly that need this driver then I might pay but since I want just to test it them what options I have. The US distributor looks like do not have trail driver, so I do not think I have any options besides listen the comments of other and bet that it might work for me. As far as I concern this is an idiotic situation.

The Goto SG-555P driver look like will be OK match for my 183Hz horn.

http://audio-database.com/GOTO%20UNIT/unit/index.html

It said that optimal crossover is from 200Hz - 4kHz that might be very good for me. This time a near new pair of Goto SG-555PS went for $2800, in July a pair of them in less exiting condition were sold for $1800. So, I think $2K is a reasonable price for a pair of Goto SG-555PS in good shape.  In Japan the list price for Goto SG-555PS is under $3K and the street price 25% lower as usually.

I am still not at ease with Goto drivers. Might be it would be a good opportunity to try them. If I have somebody who sends me one of those Goto SG-555 for a few days…

Ok, I loaded the S3 driver into the new multicells, use my extra of bas sections as a pedestal for multicell, connected 2 extra bass channels to ULF amp and the multicells to full range amps with no crossovers. Yes, I got a VERY good width and the whole things dancing now more interesting. At the same time something that I do not like show up in sound. It is like you are very hungry and instead of fancy-shmancy cooked piece of sophisticated pork steak somebody give you an ordinary cooked piece of veal but large amount. Sure you not going to be hungry if you eat a half cow but the ceremony of eating become kind of different.

It is highly possible that to get this configuration to work as it might everything need be very painstaking calibrated and aligned – it is not how I have it now.  I am not planning to get anything done better unit I get my fixed PP2000 back, so it will be sitting as is.

There are 3 things that are very certain at this point:

1)      The main dispute with myself that I need to address: if I would like to have large side-located multicell with small throat driver and long horn or if I would like to have large throat driver with shorter multicell sitting in the position of my current Fundamental Channel

2)      If I do it again then I would do my multicell differently or request it to be made differently

3)      I don’t like that Macondo grows. It becomes to lose some elegance. Perhaps I need to redo the enter frame with respect of the new room and new listening distance? If I could outsource this task then it would be so great…

zanon wrote:

As a horn player, I sometimes introduce honk because it introduces a stress tone that feels louder, without actually having to play louder. THis gives me more dynamic flexibility, and I can communicate more extremes. I have never heard this introduced in playback

Zanon, first of all I would argue that honk used ONLY as “brass virtual clipping” in order to frost the cake of dynamic range. In fact I would says that if it always used this way then we might talk about coloration of the playing techniques. Sure as a human you make your judgment when to spice your loudness with honk and to which degree, this is the whole beauty. Second of all I would state that all brass instruments in one way or other tend to have honk and it never considered as especially negative characteristic.

Then we have a playback. Sure the methods and the means of creating sound by live people and by playback are radically different but the final result and the goals are very much the same. If so, then why we OK are with honk of live sound but reject honk of playback? Sure, live honk and playback honk are coming from different reasons and have different quality but this explanation will be final ONLY for the people who have wrong global perception of what playback does. Let me in extremely abridged forms to explain what I mean I it will take a next paragraph and then I will go back to the subject.

You see, 99.999% of audio people out there are under a stupid, illusionary believe that playback is just more or less accurate carbon copy of live sound and they are trying to make their home sound to mimics what they hear in symphony halls. So, as the result sit in their listening rooms around the face figures of Madame Tussauds and are trying to get inspiration from a raised Marilyn Monroe’s wax skirt.  The truth is that playback is a representative of live sound but it is a completely new sound, not the replica but rather a delegation of intend. This is a big subject and I do not want to go in there here but it needs to be very clear what I stay on it. Furthermore, when I meet audio people who do not understand (majority) or do not support my notion of playback as a NEW consciousness (contrary to replica) then I instantly deny to those people any presumption of audio normality and consider that they do not practice audio but “psychologc acupuncture by sound” ™.

Now back to the notion of honk in playback. If we agree that playback is not replica of original sound but new sound then why it shell not have own honk, or more accurately say the “impression of honk”? Of course it might. The key in my view is very clearly understand the nature of honk during live sound and played back sound. Live sound have honk as expression or as organic narrative. The useful honk in playback (we do not even consider honk as errors or mistakes of playback) has no knowledge about expressionism or about intention and understand ONLY phase/volume algorithms. I do not think that it is possible to make playback to produce honk properly without a dedicated honk modulator, the modulator that will run own logic, but I do not see why it might not be done so. I have for years one old metal “narow” horn that I still keep I plug from time to time and from which I get a phenomenally wonderful honk. If the volume of and the bandwidth of the horn are right then honk auditable only sometimes and give to sound (sometimes) that wonderful effect of “cold nose on brass”. It is very nice to soft let say the brass of Tokyo Philharmonic or even  Chicago Symphony. A proper amount and quality of honk does not soft them in volume but soft them in feeling, adding some humanity and palatability.

Sure brass shall be able to play clean but clean brass does not exist in my view. Do you remember that roaring opening sonority of the second movement of Tchaikovsky Fifth and the entrance of the horn? Try to visualize if as “clean” brass with any honk. What will have left - the air ring from pipe? The point is that proper tone and proper honk create positive venture on brass. It is not a problem in audio generally but in horn would we so afraid of honk that we do throw baby with water in my view…