haralanov wrote:

Are there any signs for worsened transient response of your midbass channel due to the sharp electrical filtering?

rickmcinnis wrote:

I would worry that there could be an interaction between your electrical filters and the filter formed by the horns themselves. I, too, like to trust my ears and I would ten to trust yours more than mine but nonetheless you have created quite a complicated filter with the mid-bass horn.  Akin to several Doctors giving a patient  drugs without considering how they will interact with what the other fellow has prescribed. My instinct is to simplify the chain of filters and see what happens.  I respect your search for perfection but sometimes only compromise is possible.

This is a very important question as since very beginning of the projects it was questionable if I would be able to get away with the back/top firing position of my midbass horn. So, as now, when the midbass horn project is over and horns fully integrated into Macondo and into the room, does the midbass horns indicate themselves as horns are in the “wrong” location? Was I able to hide that location of the horns by my integration techniques? Was it a mistake to plan the midbass horns at the Behind-Above location as I did? The reason I would like to cover these questions is because I feel that the content of this thread is in a way a good blueprint for somebody who would like to follow my steps and built a similar horns in your own house. Do not take my “steps” too literally. There are many rooms out there with many options to position and variance of horns at the “wrong” locations.  My positioning of the midbass horns is just one of the options, there are many others. So, without generalizing too much I would like to cover my view on general atypical horn positioning and  about my behind-above in particular.

It is my feeling that there is absolutely nothing that can beat presentation and imaging of a properly positioned midbass horn or perfect room setup with midbass horn. In the perfect scenario the midbass would sit on the sides of MF Island. I have depicted it a few months back:

I do not have this option and my objectives did not even comply with this schema. May objectives were to make the midbass horn INVISIBLE IN THE ROOM and TIME ALIGNED. I absolutely successfully addressed my adjective; do I pay any toll for it by sonic problem related to my midbass horn imaging? Yes and now, and to evaluate it a bit complicated.

Under normal circumstances, sitting in my home and listening music there is absolutely no indication that there is a pair of 42Hz horns in the attic. The sound is full and coming very much from Macondo; in fact it is almost like a freak show with 115hz horns look like reproduce the whole bass spectra. When most of the LF events sharpen then bass localizes as it come from upperbass horn. This part of very, very, truly very good. However, there are some harmonic sequences (and only in classical repertoire) where sound coming ONLY from midbass and there is no sound from other channels. During those moments the midbass horns do indicate themes. Two moments however need to be considered to understand it correctly. The moments where no sound coming from Macondo are VERY seldom.  Also during those momants the horn does not localize behind me but rather Behind-Above, where 70-80% come to Above. The sound does not localize Behind-Above or better to say Behind-Above-Above-Above but rather sound moved a bit up. If MF move up then we have imaging shift –it is very visible and annoying. When however the lower end a move a bit up it is much less attracts attention as there is no focusing point. The sound instead of moving up just begins to fill the room from ceiling – with some music it creates very good effect.

All of it is very hard to delegate in description. Do not forget that miss- integration of my midbass horn is something that I very deliberate is trying to learn to recognize and to acknowledge. So I am much peakier and more anal then an average listener. There is a huge possibility that an average listener would not even recognize the difference. Sometimes I can play 5-6 CDs before I get a feeling that Behind-Above micro-event let itself to be heard. So, it is not so much in face and the Behind-Above is very non-invasive event what it take place.

What can I recommend to the people who are considering the similar deals on Attic and afraid that the Behind-Above positioning would be too critical? Well, invest in your education, fry over to my place and see how the Behind-Above works. I will be demonstrating to you the worst of the Behind-Above character and you will be able to make your own evaluation if it worth for you to be concerned.

My personal feels is that Behind-Above character works fine and evaluating all pluses and minuses that I know now I would still go for exactly what I did. Yes, some of the imaging moments that I was able to get in my old room are not available in my new room. I do not related it to Behind-Above location of my midbass, it also, not the end of my journey and I might further up find ways to shape up the imaging.  In the end I feel that Behind-Above location was a success. There are some adverse moments but they would be in ANY location of the midbass. Even if I go for the perfect room setup depicted above then the horns would have MUCH MORE reflections caught into the mouth with all negative consequences to Sound. One of the greatest thing of my Behind-Above location is that the horn is loaded to practically to open air, have no reflections and therefore it decays very softly. The advantage to sound is so huge that in my view it overrides any other advantages of disadvantages. This is my personal view and I built my horn for my personal use. I do clearly see the advantages and disadvantages of the Behind-Above idea and I do feel that with good sensibility the Behind-Above location my be very much well performing.

Romy the Cat wrote:

When I have my old transformer 11:1 then I had the midbass horns calibrated so perfectly that you can tune a large symphonic orchestra by it sound. It was spectacularly stop-on setting with any type of music if played it never was too much or too little – it was perfection that might be taught in the hi-fi schools if they exists. But I did not have power and I went for 9:1. Since then I keep playing the modesty games, constantly rolling off .25dB….

Romy the Cat wrote:

The subject of midbass nasal sound is very interesting. In addition to all OTHER aspects that might lead to midbass honk I would like to note that there is one that is in my view greatly overlooked – the precision of response. What I said that my new midbass horn has absolutely no honk then it does not mean that it has no nasal artifact under any condition. If I drive the horn in wrong frequency range and at worn volume then it will have all possible problem. What I do say is that when I very fine tune the horn in respect to my other channel and make the horn to operate in the mode that I would call “proper balance”, then the horn does not exposit any sights of nasal tone. I kind of even miss this very fine honk as I do like it. Live sound has it as well, and a very fine touch of it from horn is something that I like. My horn does not have it or perhaps I need to drive it a .25dB harder somewhere, I just do not know at this point where. His is what I am learning nowadays.

Perhaps the bypassing or moderating the high-pass filters would so it, or modification of the throat’s profile or injection of things into mouth, or use some kind of reentry reflectors would do it… I have many ideas but I do not want to go and to try them, not to say the many of them will modify the sound of the horn to higher degree then produce honk. I do not want to change the sound of the horns; I juts wan to add some very very very minor honk, not any honk but  good honk…

Did anybody research the subject of deliberate good horn sound?

Romy the Cat wrote:

It is in a way ridicules. For years people who build of use horn fight with honk in horn, particularly in midbass-upperbass-lowerMF horns. I built my midbass horns and it has no honk, I mean no honk ever of any kind. Still, I am not content. As I wrote before I do look forward to get SOME very deliberate and very specific honk. My midbassis insultingly neutral, it has fantastic dynamic, fantastic behavior at super high and super low levels, free from any coloration, superb transients, very good discriminates color and set at very proper level in the room. Everything is great but at time I feel that it is too horn-neutral, not tone-sterile but horn-neutral. It sounds like very good quality direct radiator with 109dB sensitivity driven by 1kW amplifier. What I would like to do however is to make my midbass horn to have a very slight pouch of horn honk. Yes, I am taking about a injection to very deliberate non-neutrality and very premeditated coloration.  Sure I will not my horn to have honky sound, we are taking about a degree. I know exactly what I would like to distort in the sound of my horn and what result I would like to accomplish, I just have no idea HOW to do it. Perhaps the bypassing or moderating the high-pass filters would so it, or modification of the throat’s profile or injection of things into mouth, or use some kind of reentry reflectors would do it… I have many ideas but I do not want to go and to try them, not to say the many of them will modify the sound of the horn to higher degree then produce honk. I do not want to change the sound of the horns; I juts wan to add some very very very minor honk, not any honk but  good honk… Did anybody research the subject of deliberate good horn sound?

If it so then I am not very comfortable with idea that when I think about ULF I think about sound. It shall not be this way. From a different perspective what is “good honk”? The “good honk” is not a honk per say but rather a very special harmonic softness that certainly would not hurt my ULF channel. Did the ULF made my midbass horn to sound harder? It is very possible to be so. I wonder how I can test it? I have no way to modify the sound of my ULF and I have no way to change the ULF amplification, which is basically a transistor amp with all consequences of SS not able to produce proper bass. I would LOVE to try to drive my ULF tower with a powerful SET but where can I get 100W SET? I had a few threads hat covered the subject:

http://www.goodsoundclub.com/Forums/ShowPost.aspx?PostID=5200

http://www.goodsoundclub.com/Forums/ShowPost.aspx?postID=2136

… but I am not going to built anything  juts to “try”. It would be nice if I was able to borrow somewhere a SET amp that would be able to output 100-150W but then I realized that it would be most likely a full range set but I would need LF DSET. I might get as a test a power amp with 211/GM70 tube and to wind to it LF DSET transformer with huge inductance and no sections – it will give me some point of reference if it still be in class A. However, I am not convinced that what I am taking is coming from amp not from my drivers in woofer towers or from the way how my woofer towers are built (slightly over damped). Anyhow, I do feel that it does make sense in my search for “good honk” to move the accent from my midbass horn to my ULF thread. If I will do anything about the “good honk” then I will continue my talk in the other, more appropriate thread.

I was listening recently my Carl Schuricht’s Bruckner and I again noted what I am been noting for a while. I feel like my Midbass horns begin to sound a bit saggy. It is not too but and the degree of change is very minor. It is not even auditable at normal dally listening but if to observe the composite experience from multiple week then I say that the effect is there. Being me, if I acknowledge the problem then I do pay attention to the problem with much attention. Yes, I do feel that there was some very gradual change in my Midbass sound for the last 2 month or so.

Thinking what would it be I can propose two factors:

1)    My new Vitavox 15” drivers that were sitting in box for 60 years finally got broken-in completely.

2)    The high temperature at attic has softened the suspension of the drivers.

In both cases most likely the resonance frequency dropped for a few Hz that lead to a very mild sagginess of my midbass sound. I did not measure the resonance frequency nowadays, probably I shall… Most likely two processes worked together and second one strained the first on.

I have a remote humidity and temperature sensor sitting atop of the midbass horns back chambers. At the hottest day of this year so far with temperature of 94F I have at my attic 121F with attic venting off.  My attic does not have venting roof ridge and use side venting. I installed a powerful exhausting fan with thermostat, rated for twice size of my attic.  It cool attic very well but I did not note any improvement in sound since the exhausting fan went up. Indeed the difference is VERY mild…

What it boils down is that I think I need to revise the size of my back chamber in respect to new lower resonance frequency. It will take a little filling of the back chamber to drive the Fs up back to 42Hz. If I recalibrate the thing for summer, let say for 75F then during the winter I might put in the back change a very small heating element with thermostat and to stabilize the temperature. I still am contemplating it and not so egger to proceed. I like what I have now – the back change is empery as it would allow me to rotate the driver. The vintage 15-inshers with paper suspension need to be rotated 180/45 degree once a couple years if they are mounted vertically.