It is not about Dynamic Range per say but about dymick differences that I feel and that I care with good ULF he effect of rising of acoustic and tonal pressure is instant, very soft but absolutely instantaneous. Live music has feel like literally infinite dynamic range of ULF and little infinite dynamic headroom.  I do not compare live and recording music but I am talking about perception during live and reproduced music.

Thinking about it I asked myself if dynamic amplitude is something that we truly deal with in ULF.  My feeling that it is not. I feel that dynamic amplitude have very little different in ULF, it is like feeling of tsunami if you are in a middle of the ocean.  If you paid attention then you know that explicit proper compression of ULF has practically no negative effect to Sound, so the dynamic amplitude is very much not the key that I would look for.

What I think I am after is a rate change of ULF, of the very leading edge of the wave to be as distinctive as possible.  So we are taking about transient of ULF, however, because it ULF I think there is a very interesting kink on the whole story, the kink that might be overlooked by everyone, and it certainly is being overlooked by me.

Let pretend that we look visually at the front of pressure ways. It would be obvious that the higher ratio between in-wave pressure and background pressure would do better “rate change”. So, what would smear the sharpness of pressure build up? Surprisingly (of not surprisingly for the readers of my site) this morning it hit me that the problem might be in the driver time alignment.  The morons would say “not again” but the Morons did not note that I did not say “drivers time alignment” but I said “driver time alignment”. Let me to explain.

I notice that my woofer array towers worked superbly in my old room but now as much in my new room. There are many reasons why but there is also one moment that I think is overlooked. In the old room my woofers were facing directly to me but in my new room they are way out of my view. What does it is affect? Well, the woofers are 10”, some people use 15, 18 or more inch woofers. The pressure produces by a woofer originated by the woofer surface and since the surface is large then origination surface has dimensions. We know that the time misalignment or the arrival difference between let say left and right side of MF drivers, are responsible for lateral attentions of drivers and for the restricted dispersion diagram.  With bass driver we do not care as we feel that the wavelength is too long. Well, for sure at bass the dispersion patter does not change so much. However, what I propose is changing with facing-off the woofers is the density of the bass leading front. 

With 18”woofer located at 45 degree to listening spot the leading border of the pressure wave will have 9” of smeared edge, where the pressure from the closer and further side of the woofers did not arrive yet. This all very simple to test with a regular woofer firing in face and off face. What is not so simple is to develop attention to the specifics that need to be listen. You might recognize a sort of not “softness” but rather elasticity of attack when woofer’s sides are not aligned to itself. This elasticity might not be unpleasant; in fact it is pleasant but it pleasant only in context of a single canal. This pleasure might not work in context of larger picture of your sound, the way how it does not work in my case.

Again, what I described above is not uncontroversial but I would like you to know that this view do exist in me and if I could then I would like to have the ULF woofers face directly to my listening chair.

I am I wondering if my dissatisfaction with my new ULF channel is not the problem of my but the problem of the new PP2000 lower bass.

http://www.RomyTheCat.com/TreeItem.aspx?PostID=15046

at the time I start fine tuning of the ULF channel I have already used the new generation of PP2000. It might be not related but it also might the source of the problems why I do not have the lower bass as clean as I use to have. I would need to run my lower bass from PP2000 buttery to see how it goes. It would be interesting if it turns out that it was not my small woofers but the new PP2000’s bad sound in lower bass what it runs from AC.

Romy the Cat wrote:

Aura made their 1808 driver in 80s and most of the 90s and it was wonderful. It had huge high-temperature neodymium magnet, unique magnet geometry with underhung 4" edgewound aluminum voice coil.  It was the only 18-inchers underhand voice coil ever produced. The finny part that despite of the underhand configuration it had 98dB sensitivity with 2” total excursion – what a motor! The driver had paper cone, cloth suspension and had phenomenal articulation at lowest frequencies. The 1808 was suggested for 20 Hz - 200Hz but it did not sound good even at 80Hz. The Aura 1808 had free air resonance at 24Hz and required enormous sealed enclosure of 14-16 cu feet.  Wilson Audio used the Aura 1808 in their unfortunately-ported XS subwoofers and soaked from their relatively small enclosure an extra 19dB of port noise at 20Hz. Rgs, Romy the Cat

Rakesh, I moved your post to this thread as I feel it is more relevant here, I hope you do not mind. You ask yours the very same question that I ask myself. I do not have definitive answers to them:

oxric wrote:

I am presently considering an opportunity to buy some very old Aura Sound 1808 drivers, but not the Leviathan you enthused about in the quote above. My understanding is that the fairly low Qts would make the original (non Leviathan) less suitable for use in a sealed enclosure. However it also sounds as if it might work in such an enclosure if it was big enough, i.e. 14-16 cu feet. I have never liked ported enclosures but would that not be the only way the 1808 should be used?

If I use 1808 then I would never use it in ported enclosure, in fact I would not use ported enclosures for any driver in ULF channel.

oxric wrote:

I am also very tempted by the McCauleys 6174 or Maelstrom 21" but they are somewhat more expensive in Europe....

This is very legitimate concern. I have 4x1808 drivers and they might be my candidates to come up with my ULF channel but for the last 10-15 years as Aura stopped to be made there are a lot of new drivers made. How good they are comparing to Aura? I have no answer and I did not see a lot of taking about it out there. The complexity of this question is that there are a lot of variables involved:

1) Proper implementation of a given driver
2) Different people have different room condition
3) Different amps damps the bass cones differently
4) Different people have different reference points what constitute the “proper” bass.

So, in my view unless you know a person, set with him/her in the same room and compare the notes and exchange reference point about bass while listening a give reference Sound, then there is no reasons to exchange view about bass. I think the only way to learn what is “better” it to try different drivers in the different configuration and enclosures, this is how we develop the acquired taste and this is how I discovered drivers for my Macondo. I did not develop acquired taste in bass drivers. Back in 2002 I use a single 1808 driver in a large, probably 24 cu feet box. I liked the result but my objective was not 20Hz-40Hz but 9Hz. Looking back I am not sure that I would like the same result now but it was different room, different playback and the different me… I today would not trust to me 10 years back…

oxric wrote:

For what it's worth, this consideration is part of a larger question, which is what would be the ideal ULF solution for pretty much the same Macondo set-up that you have, being used in a fairly large room of 25x21 feet with a ceiling height of 8ft? I have been thinking of the line array that you are using but I am wondering whether a pair of 1808 or even a line array made out of 6 such drivers, 3 on each side stacked vertically might not prove a more versatile solution ( somewhat extreme admittedly, but with a view to the future when I will have a bigger room with higher ceilings).

Yes, this is all that I would like to know as well. Do not put too much into line array subject. You do not have a room to form proper line-array with those drivers and at that frequency. A pair of 1808 or similar drivers would be between then a single drivers but I do not think that it will be due to forming as proper cylindrical wave…

oxric wrote:

Obviously there is no question that I will be able to listen to any of these solutions so any thoughts or even considerations that I ought to keep in mind, are welcome. With regard to drving them, whilst I know that the ULF section of the Melquiades can drive the Scanspeak 10" line array, I am of course not sure whether that would be satisfactory with the Aura Sound 1808...

I use my two Scanspeak 10" towers, 8 drivers as a ready to go temporary solution. I drive them with Yamaha B2 amp, it is pure DC amp. I would not say that I like the result. It does help to my midbass horns to get reference to sonic ground but in a way it compromises the midbass lower end. My plans are find the final solution with PurePower and get my all properly working regenerators back. Then in context of a proper for bass electricity (VERY important) to tune my current 10" towers and to get best they can do. It is possible that my current towers juts do not setup up properly – I never did the final fine tuning. If in the end of my “fine bass tuning” I will not be satisfied with results then I will go for experimenting with large drivers. I have space, interests to the subject and the stupidity to do so, but it will be the final touch…

Rakesh,

Yes, life is too short but the definition of belter ULF channel is not something that one might learn during "a project next coming weekend". The most important in audio is a state of realization and obtaining this state is a matter of time I am afraid. Let pretend that tomorrow I will build/buy some kind of speaker that would do the perfect ULF channel for me. The main question would be: the perfection of that ULF channel is something that the driver and enclosure demonstrate or it is something that I am able to recognize?

There is a huge amount of people in audio who do anything doable but who failed to develop of understanding and interpretation of results. You can see tone of them at DIYaudio.com forum and at many other locations – they move hand and do actions but their projects do not advance them from listening and human perspective. This is why I never like the entire DIY community.

What I am trying to say is that the ultimate ULF channel is not only a combinations expensive driver in some kind of enclosure. The most valuable in an ultimate ULF channel is not a driver but the vested amount of system owner thoughts about what kind bass she/she is willing to get. This understanding comes literally with years. You can buy drivers; recruit a carpenter, build or by enclosures but it would serve only a solution but not satisfaction. The satisfaction is fulfillment of objectives and in my estimate a person need first to develop well formed  objectives, very clearly visualize the result and ONLY then, after the concept is conceived and clearly indentified, ONLY THEN the person might render the objectives.

http://www.goodsoundclub.com/Forums/ShowPost.aspx?PostID=432

With all frankness I thought that I have a very clear idea how I would like my sound from ULF to be. I have been thinking about it for years, looking what other do and visualizing how different I would like it to be in my own playback. However, the last few months, since I finished my midbass project, my views slightly changed. Nowadays I would like to have less ULF to midbass integration and I would like my ULF NOT to be a continuation of Music but rather to be a separate stand-alone awareness of Sound.  It is not as bad as it sound in writing and it need to be demonstrated, not explained at a web site. Unfortunately I can’t demonstrate it even to myself and I have the notion as a pure fiction of my mind, sort of a hallucination, a dream that I would like one day to render as a reality.  I do not have an itch about it, I perfectly might go along without it, using ULF as they are but if I do something about my ULF then I would like to navigate explicitly to what I want.

Romy the Cat wrote:

The most important in audio is a state of realization and obtaining this state is a matter of time I am afraid. Let pretend that tomorrow I will build/buy some kind of speaker that would do the perfect ULF channel for me... What I am trying to say is that the ultimate ULF channel is not only a combinations expensive driver in some kind of enclosure....The satisfaction is fulfillment of objectives and in my estimate a person need first to develop well formed  objectives, very clearly visualize the result and ONLY then, after the concept is conceived and clearly indentified, ONLY THEN the person might render the objectives. http://www.goodsoundclub.com/Forums/ShowPost.aspx?PostID=432

Romy the Cat wrote:

...Nowadays I would like to have less ULF to midbass integration and I would like my ULF NOT to be a continuation of Music but rather to be a separate stand-alone awareness of Sound.  It is not as bad as it sound in writing and it need to be demonstrated, not explained at a web site. Unfortunately I can’t demonstrate it even to myself and I have the notion as a pure fiction of my mind, sort of a hallucination, a dream that I would like one day to render as a reality.

Romy the Cat wrote:

However, the last few months, since I finished my midbass project, my views slightly changed. Nowadays I would like to have less ULF to midbass integration and I would like my ULF NOT to be a continuation of Music but rather to be a separate stand-alone awareness of Sound.

oxric wrote:

I believe that although you may be wrong to make a difference between ULF and the rest of the frequency range….

oxric wrote:

I see a number of logical flaws with this view and I was hoping someone else, who may have a similar feeling to yours, would try to expand on it before I and/or others start discussing or criticising what is not a fully fledged argument. The first view must be right. Without integration, and a homogeneous sound to start with, the result is complete chaos. In fact one can only look at your system to see the high order of integration ….

oxric wrote:

A second objection is that why single out the ULF channel? For instance, why not make the midrange a separate 'stand-alone awareness of sound' or all the channels to varying degrees? You have never previously and I do not think you are now making a change in your need to integrate these channels. So it looks to me that for your view to even start making sense that there must be something about ULF that makes it different to other channels, including in fact the mid-bass and upper-bass. What could that be?

oxric wrote:

I of course undertand that there is a difference in the way we perceive ULF when it comes to the way human hearing operates. I however cannot see a biological or anatomic rational that would require us to treat the integration of ULF any differently.

oxric wrote:

Could it be something about our exposure to ULF in commercial or domestic installations is so inherently flawed that we need a new language to capture the potential of the lowest frequency range? I am not convinced. I hope that as your ULF channel evolves you will tell us more about this rather novel and indeed revolutionary idea that the aim maybe is not to integrate the ULF as a 'continuation of Music but rather to be a separate stand-alone awareness of Sound.'

Romy the Cat wrote:

The major minor thing remains to find different lower bass. I said “minor” thing as my lower bass is not bad, in fact I do insist that it is very proper lower bass as I did set it up lately properly…..Despite that I insist that my currant bass is the PROPER bass I still would like to have slightly different, I have a feeling HOW it shell sound but I do not know at this point how to express it to myself in the format that I would be able to understand or implement. The things with bass will be continuing but without emergency of any kind.

Romy the Cat wrote:

However, the last few months, since I finished my midbass project, my views slightly changed. Nowadays I would like to have less ULF to midbass integration and I would like my ULF NOT to be a continuation of Music but rather to be a separate stand-alone awareness of Sound.  It is not as bad as it sound in writing and it need to be demonstrated, not explained at a web site. Unfortunately I can’t demonstrate it even to myself and I have the notion as a pure fiction of my mind, sort of a hallucination, a dream that I would like one day to render as a reality.  I do not have an itch about it, I perfectly might go along without it, using ULF as they are but if I do something about my ULF then I would like to navigate explicitly to what I want.

I do think about my lower bass, trying to get what I want. My current bass is very “integrated” and very musical. It low, it is large, it is extended and it is in away grandeur and it has nothing close with faulty Hi-Fi impressiveness. It never take over sound and never indicate the “bass efforts”. It is what it is and listening music with this bass I have no motivations or need to improve anything in lover bass.

However, I do have interests to have my bass to act differently.  What I would like is not the change of bass itself but the change how my room is being filled with bass. I mean I would like to be able to sense that my bass channel is on while my playback is not playing. I mean I would like to bias up my room by some excessive ULF pressure from my lover bass channels. The properly ULF biased room eats bad sounds. The LP clicks, the tape hiss and any other externals noises become not to be noticeable and the room gets that feeling of “space of empty opera theater.” The ULF channel us a mechanism to extend the boundary of the pool into which one dives – the larger pool the less back reflections from the pool boundaries…

I kind of know how to get the ULF to do the “boundaries bias” but what I reach any more effective ULF biasing I do corrupting my auditable lower and midbass. So, I kind of looking and understanding what kind alternative lower bass I might have in order the lower room biasing bass to be a separate entry with my musical lower bass. I do not have a solution yet and I am keep thinking about it. Right now I am waking around my clients offices, knocking the walls and desks and listening how they response. I am looking for an inspiration, perhaps in a wrong places...

Romy the Cat wrote:

My current bass is very “integrated” and very musical. It low, it is large, it is extended and it is in away grandeur and it has nothing close with faulty Hi-Fi impressiveness. It never take over sound and never indicate the “bass efforts”. It is what it is and listening music with this bass I have no motivations or need to improve anything in lover bass. However, I do have interests to have my bass to act differently.  The properly ULF biased room eats bad sounds. The LP clicks, the tape hiss and any other externals noises become not to be noticeable and the room gets that feeling of “space of empty opera theater.” The ULF channel us a mechanism to extend the boundary of the pool into which one dives – the larger pool the less back reflections from the pool boundaries… I do not have a solution yet and I am keep thinking about it. Right now I am waking around my clients offices, knocking the walls and desks and listening how they response. I am looking for an inspiration, perhaps in a wrong places... Rgs, Romy the Cat

Romy the Cat wrote:

The properly ULF biased room eats bad sounds. The LP clicks, the tape hiss and any other externals noises become not to be noticeable and the room gets that feeling of “space of empty opera theater.” The ULF channel us a mechanism to extend the boundary of the pool into which one dives – the larger pool the less back reflections from the pool boundaries…  I am looking for an inspiration, perhaps in a wrong places... Rgs, Romy the Cat

Paul S wrote:

Rakesh, if Romy's ULF is "faultless" at this point, then he should play the lottary - once.  Perhaps part of the quandry stems from confusing "bass" with ULF.  Once you let go of that, it better falls into place. As for the pops, clicks, tape hiss, etc., in the best cases they are present without interfering with the music.  Ideally, all extraneous noise can be minimized and/or "set aside" from the music, and there are actually rote ways to facilitate this, and Romy has either included his observations about ULF in this context or he has included the noise issues in the context of "ULF" features. One more thing is the "groove echo" foreshadowing of change that may make us at least appear to be out of sync with our own manifestos.  And every so often, a change makes the need for it clear.

oxric wrote:

If the issue is merely to recreate a better sense of the live performance….

oxric wrote:

As for the use of the multi-cell, I understand why you did not go for it much better now. It is interesting to note that aesthetic considerations can sometimes preempt something that was nonetheless deemed beneficial in other respects. Life, even our pursuit of perfection in our audio systems, has to be a balancing of priorities after all..

I have with bass not a problem but dilemma. I do not have problematic bass but I have a dilemma how to supplement my current bass with ULF without affecting my current bass. Adding ULF defuses my current bass, renders the bass phasing to be more generic and I will not tolerate it.

So, let analyze the situation and to build some rational behind it. I own 3 major ingredients– I have a great all together bass, I know what I would like to get as a result and I know how to discriminate successes and failures. What I do not know is the reason why my current ULF does not do what I want what I run it at full throttle. So, let analyze the possible reasons for underperformance.

1)      Instrumental problem: wrong ULF transducers wrong amplifiers.

2)      Implementation problem: wrong crossover frequency and slope.

3)      Timing problem, including the horizontal alignment.

Do I have instrumental problem? Possible. I would like to have larger drivers with resonant frequency of 11-12Hz. I do not have such drivers. The 10 drivers that I do have are 20Hz driver and it is very low. My problem is that I do not have just 12 of them but I have 24 of them. If I engage all of them then I will have an equivalent of ten 18” drivers – a LOT of displacement volume at true 20Hz and with very linear excursion. The amplification? I still think about it. Frankly the Instrumental subject might underperform but it is in my estimation is NOT the main reason. The character of the ULF sound and the way how ULF crap over my general bass advise me that I need to look somewhere else.

Implementation problem. As long as I spent time with placing with my ULF crossover it might be not enough time. I still might have wrong everything and the reasons why I was not a able to make the things to work in the way I want to is because the Timing Alignment.

This brings me to the last subject: the arrival aligned and the axis alignment. We so much believe that alignment s not relevant to bass that we do not even think about it. What we are taking about axis alignment we feel that for that low frequency the wavelength is so long that time difference in arrival from right side and left side of woofer is irrelevant. It might be all true but might be THAT is responsible for smearing of my bass by my ULF? I know that in my old place I had absolutely no problem with ULF but in my old place ULD and bass was reproduced by the same channel. What however was also in my place – my bass towers were in time- aligned position and the woofer were looking directly at me – there was no right/left side of driver misalignment.

So, looking for those 3 candidates I think I need to filter out the Timing problem first and if it is a factor then it will crap over other reasons. So, no matter how much my aesthetic inclinations protest me to do it I need to bring my ULF section right outside of Macondo, time-alight them and to see what happens. I think it has to be the burst step…