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Old 24th March 2008, 12:01 PM   #111
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More show and tell:

Affect of air mass load on vibration velocity across a speaker dust cover.

Click the image to open in full size.
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Old 24th March 2008, 12:59 PM   #112
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Quote:
Originally posted by Daygloworange - Post #97
Alex,

In the interest of further attempting to scientifically measuring the reported effects of EnABL, I'd like to try and replicate your results (and/or others') and have them tested, to try and determine a correlation between what is subjectively reported and what is measured with speaker measuring equipment and techniques.

BudP and Dave from Planet 10 have agreed to be part of a controlled experiment with speaker drivers.

I've managed to enlist Al from RAW Acoustics to measure some off the shelf speaker drivers that both BudP and Dave from Planet 10 are then going to treat after the raw drivers are broken in and measured by RAW.

Both BudP and Dave will then independantly receive each, some of the broken in (and measured) drivers, treat them, then send back for post treatment measurements by RAW.

We then plan on having the (post EnABL treated) drivers sent to another facility for tests as well, to check for discontinuity between final (post EnABL) measurements.

I'd also like to see if we can measure any effects that have been reported about EnABL being successfully used to minimize diffraction on speaker cabinet edges, and effects on ports in speakers.

Based on what I have read, we can do this in a non destructive way with a decal type EnABL pattern.

If you can provide me dimensions of the patterns that yield the best results in both those instances (and the most effective applications), I can have them reproduced by having a colleague of mine cut the patterns.

We can have the patterns computer generated, and cut on a plotter out of adhesive backed vinyl material used in the graphics industry, which comes in various thicknesses. We can have those patterns weeded and pre-masked for easy application on baffle edges and speaker ports.

Just so there is no disconnect, I'd like clear instructions on how to replicate the most successful EnABL treatments on baffle edges and ports, and their correct application.

If someone has files drawn up, I can reproduce those. Short of that, if you can provide me with dimensions and measurements, I can draw them in CAD myself and then have the EnABL patterns cut and pre-masked, then sent to RAW for testing.

We will provide full details and documentation of how we will replicate the patterns, and how we conduct the tests.

In the interest of full disclosure, I'd like to keep all correspondances about this here in this thread, instead of private messages.

Cheers
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
Attached Files
File Type: zip enabl block size calculator - v2.0.zip (19.4 KB, 1490 views)
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Old 24th March 2008, 01:26 PM   #113
dlr is offline dlr  United States
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Default No one is grasping the import of john's posts

Quote:
Originally posted by BudP
ScottG
I don't think you will see it doing anything.
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.

Quote:

Couldn't agree more. This very disconnect appears to be the heart of the "mystery" that surrounds this simple set of patterns.
Bud
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.

Quote:
Originally posted by ScottG

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.)
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.

Quote:

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)
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).

Quote:

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).
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).

Quote:
Originally posted by BudP

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.
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
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Old 24th March 2008, 01:30 PM   #114
soongsc is offline soongsc  Taiwan
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Quote:
Originally posted by john k...
More show and tell:

Affect of air mass load on vibration velocity across a speaker dust cover.

Click the image to open in full size.
I take it that when they say internal pressure it means inside a chamber where the DUT is?
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Old 24th March 2008, 01:38 PM   #115
dlr is offline dlr  United States
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Quote:
Originally posted by Alex from Oz


Here are details of what I have done that consistently produce audible changes.

(snip)

Happy to answer any questions.

Cheers,

Alex
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
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Old 24th March 2008, 01:44 PM   #116
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Quote:
Originally posted by dlr

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
dlr,

Perhaps you should re-read Daygloworange's post.

Cheers,

Alex
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Old 24th March 2008, 01:45 PM   #117
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We would prefer if this thread concentrated on the objective side, however whilst this excludes subjective ratings, it doesn't exclude application techniques where they might have a measurable effect.
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Old 24th March 2008, 01:51 PM   #118
dlr is offline dlr  United States
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Quote:
Originally posted by pinkmouse


We would prefer if this thread concentrated on the objective side, however whilst this excludes subjective ratings, it doesn't exclude application techniques where they might have a measurable effect.
This will open it up to everything, whatever it might do.

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Old 24th March 2008, 02:01 PM   #119
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Quote:
Originally posted by soongsc

I take it that when they say internal pressure it means inside a chamber where the DUT is?
Obviously inside the chamber.
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Old 24th March 2008, 02:04 PM   #120
Carlp is offline Carlp  United States
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Quote:
I thought that this thread was to be limited to technical, as in objective, aspects, not unsupported subjective opinion.
Here, here. And since we can't speculate on whether or not there is even anything to measure, and theory says virtually nothing will happen, and data we've seen so far says almost nothing happens, this thread will now be closed for lack of anything to talk about...



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