ScottG,
Very cool, particularly since I used to do humpback whale research in Alaska in a former life. Now, to me the real implication of this link is that a simple observation from nature has perhaps generated a paradigm shift leading away from the currently accepted theories. I'm not saying anything like that is at play with EnABL, but it can't hurt to be open to all possibilities.
Carl
Very cool, particularly since I used to do humpback whale research in Alaska in a former life. Now, to me the real implication of this link is that a simple observation from nature has perhaps generated a paradigm shift leading away from the currently accepted theories. I'm not saying anything like that is at play with EnABL, but it can't hurt to be open to all possibilities.
Carl
Carlp said:
It is cool.
Of course prop blades for wind generators would be a HUGE market.. As well as passenger and transport aircraft (and maybe its time for a "U3"), BUT I personally think that this coupled with the massive strides in solar power have the potential for essentially a very cheap upper atmosphere satellite network. (..i.e. a "network" of high altitude solar powered UAV's.) Thats IF the technology pans out.
As for Enable..
Functionally I don't "see" it doing much. Not the basic design, but rather the execution. IMO the pattern would need to be embedded into the diaphragm itself rather than simply residing on the surface or being a part of some lightweight surface layer. It just doesn't seem to be effecting enough mass in its current config. - UNLESS its used on a *very* low mass diaphragm that isn't particularly rigid. Given the right circumstances in a commercial design that has it embedded into the driver - then you might have something (..i.e. something that would actually attenuate the transmission to the surround and reduce the "rebound" from the surround back into the diaphragm).
soongsc said:
Sorry, I guess I misunderstand what you mean Soongsc. I posted the link to the ripple tank applet, because with it, you can create wave simulations that look just like those pictured. Suspiciously, right down to the colour scheme.
john k... said:
Well, I gathered that they were just a mock-up illustrating the difference between point and planar sources.
ScottG
I don't think you will see it doing anything. From the rest of your statement it "sounds" like you are about ready to try EnABL out on a driver. Low mass, high mass, stiff, limp, doesn't much matter. Bring an off axis picture to the other EnABL site and I will provide you with pattern placement details.
Couldn't agree more. This very disconnect appears to be the heart of the "mystery" that surrounds this simple set of patterns.
Bud
I don't think you will see it doing anything. From the rest of your statement it "sounds" like you are about ready to try EnABL out on a driver. Low mass, high mass, stiff, limp, doesn't much matter. Bring an off axis picture to the other EnABL site and I will provide you with pattern placement details.
Couldn't agree more. This very disconnect appears to be the heart of the "mystery" that surrounds this simple set of patterns.
Bud
BudP said:
It wasn't a literal statement..
However, while even under most testing you may not actually see much effect either - thats perhaps the point (..and NOT as you have represented).
Rather,
NOT that it doesn't show much effect (or is an extremely limited one), but rather that if utilized in a slightly different fashion it *may* well show a substantial effect.
With regard to my non-literal previous statement..
The one area I *can* "see" it effecting is with regard to surface reflections and upper freq. tonal behavior for a given driver. (..and of course effecting the higher freq. behavior does to some degree effect the *perception* of lower freq. behavior.)
The thing is though, the boundry layer itself may in many applications be contributing more, (perhaps much more), to this than the Enable pattern - and *that* is something most DIY'ers are unlikely to fully assess (regardless of any measured changes or not).
Perhaps limiting its current use even more is that this upper freq. tonal coloration can usually be avoided with a decently designed/implemented low-pass crossover (..and of course the exception would be tweeters).
Still, there are those that use full-range drivers (and often operated full-range). Additionally there are also those that will (for their own reasons), use drivers up "higher" then they ideally should (and/or with a lower order low-pass than is advisable for a particular design).
Still, it *is* speculation on my part - but I think not unreasonable speculation.
ScottG,
And some very good speculations at that.
I think it might be very informative for you to obtain, if you don't already have some, a pair of inexpensive two or three way speaker systems. Since I treated my first ever full range driver just a year or so ago, my previous work has been with multiway systems.
I have some 30 plus years of experience with multi way speaker systems. Some were pretty decent attempts at utilizing drivers within their "piston pass band" and many others were pathetic attempts to do so. For the systems that were serious attempts to use drivers correctly and also utilize their crossovers to mate those drivers correctly, the effects of EnABL were limited to those described earlier, in the original thread here.
http://www.diyaudio.com/forums/showthread.php?postid=1457401#post1457401
These effects are easily audible from about 200 Hz on up. They are noticeable in lower frequencies as a lack of "noise" in the portrayal of things like Bass Violas, the bottom keys in a piano, the pressure from a sousaphone, the ripples of force from a bass drum.
My personal systems have always been multiway, with all drivers and baffles patterned. Alex from Oz has worked out an interesting adaptation for baffles and bass reflex ports. I do not use single port bass reflex for low frequency propagation, so I have no experience with what he has discovered.
If you are going to speculate and perhaps experiment with embedded patterns, I think you should acquaint yourself with what the current state of this art provides. Certainly a couple of people have gone forward with experiments, Soongsc and Alex, and discovered results that have advanced beyond my applications. I applaud these endeavors and help where I can.
Bud
And some very good speculations at that.
I think it might be very informative for you to obtain, if you don't already have some, a pair of inexpensive two or three way speaker systems. Since I treated my first ever full range driver just a year or so ago, my previous work has been with multiway systems.
I have some 30 plus years of experience with multi way speaker systems. Some were pretty decent attempts at utilizing drivers within their "piston pass band" and many others were pathetic attempts to do so. For the systems that were serious attempts to use drivers correctly and also utilize their crossovers to mate those drivers correctly, the effects of EnABL were limited to those described earlier, in the original thread here.
http://www.diyaudio.com/forums/showthread.php?postid=1457401#post1457401
These effects are easily audible from about 200 Hz on up. They are noticeable in lower frequencies as a lack of "noise" in the portrayal of things like Bass Violas, the bottom keys in a piano, the pressure from a sousaphone, the ripples of force from a bass drum.
My personal systems have always been multiway, with all drivers and baffles patterned. Alex from Oz has worked out an interesting adaptation for baffles and bass reflex ports. I do not use single port bass reflex for low frequency propagation, so I have no experience with what he has discovered.
If you are going to speculate and perhaps experiment with embedded patterns, I think you should acquaint yourself with what the current state of this art provides. Certainly a couple of people have gone forward with experiments, Soongsc and Alex, and discovered results that have advanced beyond my applications. I applaud these endeavors and help where I can.
Bud
Yesterday John provided this link;-
http://www.acoust.rise.waseda.ac.jp/publications/happyou/icassp/icassp-oikawa-2005march.pdf
Figures 4, 5 and 6 show how CT averaging develops a steady state wave image.
This is fair enough because it was the intention for that project, but is it not the case that we can hear some of the lower level figure 4 abberations as they arise in real time, but which were averaged out ?
Also is it not likely that such reproduction abberations are likely to be greater at moments of drive change and especially with complex waveforms, such that any EnABL investigation needs to record changes in response to live signals.
Should this be the case, and in view of the fact that changes are likely to be greatest below one tenth of average level, if such examinations are completed digitally on live waveforms ( as opposed to already subtracted analogue waveforms ) then the bit/frequency resolution necessary prior to subtraction would need to be far in excess of that necessary for mere listening alone ?
Cheers ............. Graham.
http://www.acoust.rise.waseda.ac.jp/publications/happyou/icassp/icassp-oikawa-2005march.pdf
Figures 4, 5 and 6 show how CT averaging develops a steady state wave image.
This is fair enough because it was the intention for that project, but is it not the case that we can hear some of the lower level figure 4 abberations as they arise in real time, but which were averaged out ?
Also is it not likely that such reproduction abberations are likely to be greater at moments of drive change and especially with complex waveforms, such that any EnABL investigation needs to record changes in response to live signals.
Should this be the case, and in view of the fact that changes are likely to be greatest below one tenth of average level, if such examinations are completed digitally on live waveforms ( as opposed to already subtracted analogue waveforms ) then the bit/frequency resolution necessary prior to subtraction would need to be far in excess of that necessary for mere listening alone ?
Cheers ............. Graham.
More show and tell:
Affect of air mass load on vibration velocity across a speaker dust cover.
Affect of air mass load on vibration velocity across a speaker dust cover.
An externally hosted image should be here but it was not working when we last tested it.
G’day Daygloworange,
Thankyou so much for organising some measurement and testing for EnABL on ports and baffles.
There is so much potential with this aspect of EnABL because there is need to modify drivers to experience some of the magic that EnABL offers.
However, those that have already EnABL’d their drivers (or plan to) will find baffle and port EnABL is a wonderful compliment to their drivers.
Here are details of what I have done that consistently produce audible changes.
Block Materials
I have not used paint in any of my experiments.
I have successfully used the following:
a) Aluminium kitchen foil backed with double sided tape
b) The sticky sides of thin plastic bandaids
c) PVC Duct tape
The proposed adhesive backed vinyl should be fine for the tests.
I’m envious that you can get the pattern pre-cut – this will save a lot of time and energy.
EnABL Pattern
I follow the pattern dimensions exactly as described in the patent.
Variations of the pattern have produced some really interesting but strange audible effects.
However, in my experience, the ‘correct’ EnABL pattern seems to produce the best outcome sound wise.
Port EnABL
All applications of the EnABL pattern to ports have so far produced audible changes.
The common success factor I have observed is that the port/s being treated must directly load the driver.
I have been using around 9 – 10 block pairs and the size of the port to determine the block size. (See attached calculator).
I have only been able to apply the EnABL pattern at one end of the port (with the exception of one subwoofer, where the pattern was applied roughly halfway in).
Bass Reflex cabinets have so far provided obvious audible changes.
This is for both subwoofers and ported multi-way speakers.
I have Voight pipes, which are a hybrid between horn and MLTL (I think).
These have responded very well to EnABL port treatment also.
For Band Pass cabinets with an internal ported cavity, treating the final port does not seem to generate the same magnitude of change.
Ideally, you would need to EnABL the internal port/s as well.
For ported subwoofers with downward firing drivers, the driver is loaded by both the port and the space between baffle and the floor
So you will need to EnABL the baffle as well.
Ideally the subwoofer should be mounted on flat surface (concrete or MDF board) with the same dimensions as the baffle, and the EnABL pattern applied as well.
I have not EnABL’d a Back Loaded Horn.
BR port function is significantly different to that of a horn mouth.
Intuitively, for BL horns I would use 18 block pairs and calculate the block size based on [b/]4 x the shortest mouth dimension[/b] (assuming rectangular mouth).
Bud may be able to offer some input in regard to horns.
Baffle EnABL
I cannot say whether EnABL minimises diffraction on cabinet edges.
I do claim that there is an audible change that results from application of the EnABL pattern to baffles.
My Voight pipes have been my main workhorse for this.
I have cut and stuck hundreds of blocks of different sizes – very tedious and time consuming – but very rewarding.
I have also EnABL’d the baffles on bookshelf speakers and also small surround speakers.
To calculate block size, I followed Bud’s suggestion and use 18 block pairs and 4 x baffle width as the circumference (you can use the attached calculator for this as well).
The pattern should be applied one block depth from the edge of the baffle.
For listeners who have not experienced EnABL before, the audible change is most easily heard by EnABLing the baffle of one cabinet only and listening to them in stereo.
The speaker with the EnABL’d baffle usually sounds slightly quieter and the overall sound becomes strangely unbalanced.
New Ground – EnABL INSIDE Cabinets
I have been exploring the impact of applying the EnABL pattern inside the cabinet.
I have created audible changes over and above port and baffles EnABL by applying the EnABL pattern inside the Voight pipes.
I plan to provide a detailed post showing where the pattern has been applied and describing the changes.
It’s easier to apply what I know to an actual cabinet rather than describe it in abstract.
If you are able to provide details of the proposed test cabinet/s, I would be happy to do this.
Happy to answer any questions.
Cheers,
Alex
No one is grasping the import of john's posts
That's because no one is trying to understand the important point being made in john k's posts. Bud, you have not made a single comment that indicates any attempt at all to understand what any real data represents. Look at john's most recent post. Study the data, real data, measured data, then tell us what the implication of it is. Your answer will be enlightening as to your seriousness about determining what is really happening. The latest posted real, measured data has direct implications to the discussion about enabl.
I could not disagree more. There is no mystery. This disconnect will be connected when an analysis of the data in john's post is made. The implications in it are enormous to the discussion on enabl and added mass. Oops, sorry, I didn't mean to provide any hints.
This may be the cause of one of the primary differences in perception. It is still, though, simply a change in the frequency response as either a mic or the would detect at some nominal distance x from the driver. That is, it's the integrated output of the driver on that axis. The change, whatever it is and however it occurred, is without doubt measurable, as has been made clear a number of times. We know this to be a fact.
Are we going to go back to pure speculation on something that no one involved in this thread has the resources to determine, but has been shown (by john, again) to be without support through analysis of the physics? How about a bit more focus on that which we do know and that shows direct support for the classical mechanics (oops, sorry, there's another inadvertent hint).
It is interesting that for those in this thread who are doing any current mods to drivers in their own, personal systems, all mods are being done on full-range drivers. Must be a reason, could it be the fairly ragged upper-end frequency response that would be most highly affected by distributed mass on the driver (oops, there I go again, another inadvertent hint).
I thought that this thread was to be limited to technical, as in objective, aspects, not unsupported subjective opinion. This includes just about everything on ports and baffles to date. There's not a single piece of data provided by anyone on this. Let's at least keep this thread on-topic.
To reiterate, Bud, please tell us what you see in john's most recently posted real measurements, hard data that it is. There is one key point to be extracted from it. This is just the kind of data that you have repeatedly expressed interest in having provided. I'm interested to see if you recognize it.
Dave
BudP said:
That's because no one is trying to understand the important point being made in john k's posts. Bud, you have not made a single comment that indicates any attempt at all to understand what any real data represents. Look at john's most recent post. Study the data, real data, measured data, then tell us what the implication of it is. Your answer will be enlightening as to your seriousness about determining what is really happening. The latest posted real, measured data has direct implications to the discussion about enabl.
I could not disagree more. There is no mystery. This disconnect will be connected when an analysis of the data in john's post is made. The implications in it are enormous to the discussion on enabl and added mass. Oops, sorry, I didn't mean to provide any hints.
ScottG said:
This may be the cause of one of the primary differences in perception. It is still, though, simply a change in the frequency response as either a mic or the would detect at some nominal distance x from the driver. That is, it's the integrated output of the driver on that axis. The change, whatever it is and however it occurred, is without doubt measurable, as has been made clear a number of times. We know this to be a fact.
Are we going to go back to pure speculation on something that no one involved in this thread has the resources to determine, but has been shown (by john, again) to be without support through analysis of the physics? How about a bit more focus on that which we do know and that shows direct support for the classical mechanics (oops, sorry, there's another inadvertent hint).
It is interesting that for those in this thread who are doing any current mods to drivers in their own, personal systems, all mods are being done on full-range drivers. Must be a reason, could it be the fairly ragged upper-end frequency response that would be most highly affected by distributed mass on the driver (oops, there I go again, another inadvertent hint).
BudP said:
I thought that this thread was to be limited to technical, as in objective, aspects, not unsupported subjective opinion. This includes just about everything on ports and baffles to date. There's not a single piece of data provided by anyone on this. Let's at least keep this thread on-topic.
To reiterate, Bud, please tell us what you see in john's most recently posted real measurements, hard data that it is. There is one key point to be extracted from it. This is just the kind of data that you have repeatedly expressed interest in having provided. I'm interested to see if you recognize it.
Dave
Alex from Oz said:
Alex, most of your posts should be made in the other thread. That thread is on technique and you can say whatever you care to there. That was the reason for the split in the first place, was it not? All "testing" you have made has been nothing but unsupported subjective listening. I ask the moderators to state whether purely subjective perceptions are to be allowed in this thread. Bud tends to fall back into the subjective mode as well. Is this "technical" thread going to be allowed to diverge to perception?
Dave
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.