Umm...
How about this DIY?
Using a compressible fibrous or open cell material of initial thickness "a" and circumference "b" which is compressed by tightening an outside nut. Potentially to point of virtually complete seal.
The cross-sectional area of the interface between inner chamber and outer atmosphere seems to be important in this phenomenon so "b" can be larger or smaller to change it.
A high quality compressible material which can "spring back" after being highly compressed over time may allow the sound to be adjusted for some time into the future.
How about this DIY?
Using a compressible fibrous or open cell material of initial thickness "a" and circumference "b" which is compressed by tightening an outside nut. Potentially to point of virtually complete seal.
The cross-sectional area of the interface between inner chamber and outer atmosphere seems to be important in this phenomenon so "b" can be larger or smaller to change it.
A high quality compressible material which can "spring back" after being highly compressed over time may allow the sound to be adjusted for some time into the future.
Attachments
Quote from my post #87 :
"Aperiodic has a way of sucking the snap/life out of bass transients, at least IME. OVER-stuffing a sealed box can do this too."
I was NOT and am NOT recomending stuffing a cabinet to those levels, but merely pointing out what COULD be done, contrary to popular belief. To me, an aperiodic cabinet does much the same thing as an overstuffed sealed cabinet with regard to sound quality.
I too believe that too much stuffing can make for a non-optimal sound. I believe I mentioned that right away when I recomended a sealed enclosure to VanJerry. I said he should use the largest sealed cabinet he could get away with and stuff it to suit his taste.
"No. I prefer the driver to be mechanically well damped..."
This would refer to the Qms , no ? A lower Qms would translate to a driver with more mechanical damping ?
Perhaps the Cookbook isn't the best book out there, but I found it quite interesting with regards to his testing of stuffing materials in a decently scientific manner.
............................Blake
.......................Blake
"Aperiodic has a way of sucking the snap/life out of bass transients, at least IME. OVER-stuffing a sealed box can do this too."
I was NOT and am NOT recomending stuffing a cabinet to those levels, but merely pointing out what COULD be done, contrary to popular belief. To me, an aperiodic cabinet does much the same thing as an overstuffed sealed cabinet with regard to sound quality.
I too believe that too much stuffing can make for a non-optimal sound. I believe I mentioned that right away when I recomended a sealed enclosure to VanJerry. I said he should use the largest sealed cabinet he could get away with and stuff it to suit his taste.
"No. I prefer the driver to be mechanically well damped..."
This would refer to the Qms , no ? A lower Qms would translate to a driver with more mechanical damping ?
Perhaps the Cookbook isn't the best book out there, but I found it quite interesting with regards to his testing of stuffing materials in a decently scientific manner.
............................Blake
.......................Blake
VanJerry said:
Maybe half inside and half outside since you dont want to make a tube out of it but also have to remember, or at least consider, that material does not compress evenly just like springs dont compress evenly. But if you can break it down into several discs, or at least two then the compression of the material will be more uniform. Just a guess/idea based off of your unique thought.
Uriah
Yes, I can see both issues.
Probably all inside for aesthetics anyway. To be swappable from the outside the material would no longer be held by a bolt through its center so I'd add a little inside shelf to keep it from falling down and being hard to reach.
Multiples of smaller units would also be better due to the fact aperiodics need about 10 sq. in. of interface per cu. ft. of enclosure. Makes it tricky though to keep them equally tight. Probably help to mark treads every 5 turns with color coded perm markers. Would take a lot of these in a single multi-holed array for big boxes.
-jerry
Probably all inside for aesthetics anyway. To be swappable from the outside the material would no longer be held by a bolt through its center so I'd add a little inside shelf to keep it from falling down and being hard to reach.
Multiples of smaller units would also be better due to the fact aperiodics need about 10 sq. in. of interface per cu. ft. of enclosure. Makes it tricky though to keep them equally tight. Probably help to mark treads every 5 turns with color coded perm markers. Would take a lot of these in a single multi-holed array for big boxes.
-jerry
planet10 said:
David,
What do you think of just the enclosure used in World Design's WD25T? (ignoring it's a 2-way)
ie. Any advantage to having an aperiodic within a sealed enclosure when it comes to larger floorstanders using a big woofer component similar to the AN12 besides a final 12 dB/Oct roll-off?
-jerry
VanJerry said:
From the same guy that brought us the Dynaco A25.
http://p10hifi.net/tlinespeakers/FAL/box-plans/classicTL-revisited-WD.pdf
http://www.t-linespeakers.org/classics/dynaco.html
dave
I'm sorry, I gave the right pdf link for the WD25T but called it the WD25A by mistake. [I corrected this in the post] I'm referring to the one that uses aperiodic vents.
The whole cabinet is divided in half by an aperiodic vented upper floor. The idea is that the midrange and upper bass sees the upper chamber but the rest of the bass sees the whole sealed enclosure. A trick used by the WD25T that I see relevant to me because the AN12 forces such a large box, perhaps it's upper bass and midrange could also use help? Sort of a compromise between your position and Nihilist's?
Or, to keep the whole box aperiodic, a second aperiodic vent from the lower chamber to the outside...
The whole cabinet is divided in half by an aperiodic vented upper floor. The idea is that the midrange and upper bass sees the upper chamber but the rest of the bass sees the whole sealed enclosure. A trick used by the WD25T that I see relevant to me because the AN12 forces such a large box, perhaps it's upper bass and midrange could also use help? Sort of a compromise between your position and Nihilist's?
Or, to keep the whole box aperiodic, a second aperiodic vent from the lower chamber to the outside...
So David,
When you said you'd aim for a Qtc of 0.6 or so, and without meaning to ask you to run any sim or anything, what size Aperiodic would that ballpark at?
(I really have been trying but can't find anything online that would help me guesstimate myself...)
4 tries = 4 cabinets? or 4 adjustments to the vents?
When you said you'd aim for a Qtc of 0.6 or so, and without meaning to ask you to run any sim or anything, what size Aperiodic would that ballpark at?
(I really have been trying but can't find anything online that would help me guesstimate myself...)
4 tries = 4 cabinets? or 4 adjustments to the vents?
When David Dicks recommends a BR he recommends using 40"x14"x11.5" so this is pretty close. I know I know he recommends it for the whole range of ANs and thats odd, but it sounds good. I do believe it could sound better to, but the fact that it sounds good right now and that Nelson Pass is experimenting with the AN12 in OBs makes me to content right now to try anything else.
Going off of what Dave said about using more than one hole.... You could get around the weird compression of damping material this way. The more holes you make then the more uniform your compression could be. It solves the problem of compressing multiple layers by allowing to use one layer over many holes. On the other hand the air doesnt have to try very hard to get to the outermost holes and it does have to try harder to get to the innermost holes, so it might actually seem like a cone shaped port that is stuffed. Not sure but it makes sense that way to me.
Uriah
Going off of what Dave said about using more than one hole.... You could get around the weird compression of damping material this way. The more holes you make then the more uniform your compression could be. It solves the problem of compressing multiple layers by allowing to use one layer over many holes. On the other hand the air doesnt have to try very hard to get to the outermost holes and it does have to try harder to get to the innermost holes, so it might actually seem like a cone shaped port that is stuffed. Not sure but it makes sense that way to me.
Uriah
Hi udailey,
Well, I kinda knew going into this in the land of Thiele and Small that if I did want anything much better than Dick's infamous BR, pleasant as it may be to those who've heard it, getting guidance on the biggest AN wasn't going to be simple. My fall back was always the Cast 10" but after all the work the helpful people here have put into the 12" I'd be a tad worried of being tarred and feathered for starting up on that one
It's why I visualized a few separate multiples of the design - allowing air to get directly through each hole equally from all directions. Actually, having more than one such independently controllable unit makes for a powerful aperiodic experimentation platform as it allows you to open one more than another. It thus can simulate a variety of virtual materials that may not even exist yet by using pretty much a single standardized material.
But, I should mention that this aspect is a bit secondary right now as I struggle to even see which basic enclosure etc is even doable. I agree indications are the OB way wouldn't be anything as complicated for the large AN's. Too bad I don't have an extra few feet to accommodate this...
-jerry
Well, I kinda knew going into this in the land of Thiele and Small that if I did want anything much better than Dick's infamous BR, pleasant as it may be to those who've heard it, getting guidance on the biggest AN wasn't going to be simple. My fall back was always the Cast 10" but after all the work the helpful people here have put into the 12" I'd be a tad worried of being tarred and feathered for starting up on that one
It's why I visualized a few separate multiples of the design - allowing air to get directly through each hole equally from all directions. Actually, having more than one such independently controllable unit makes for a powerful aperiodic experimentation platform as it allows you to open one more than another. It thus can simulate a variety of virtual materials that may not even exist yet by using pretty much a single standardized material.
But, I should mention that this aspect is a bit secondary right now as I struggle to even see which basic enclosure etc is even doable. I agree indications are the OB way wouldn't be anything as complicated for the large AN's. Too bad I don't have an extra few feet to accommodate this...
-jerry
VanJerry said:
Yes, and no, respectively. It's just a variation on an aperiodic cabinet -basic damped / resistive vent approach, that's all, with a net volume of ~3.3ft^3 & is absolutely the smallest I'd consider going with one of these drivers & if you want to go this small, it's about the only available option while maintaining a reasonable FR. Trust me, you don't want to know how large a TL would need to be for these drivers.
Guidance on the AN12in isn't difficult. It's a driver & conforms to the laws of physics. Period. The principal issue is that it really does want a very big cabinet indeed. Doesn't matter if it's T/S based or anything else -it wants a big box. That last BR (with the peak at Fb) that I showed you for e.g. had nothing to do with Theile & Small -that was a trad BR alignment in use many years earlier.
OTOH, the AN 10in will work nicely in a much more manageable volume than the 12in (these things are relative) so is the canny choice of their entire range IMHO.
That is pretty darn good! Could you hazard a comparable Qtc on this? If it's not quite 0.6 how close can it get if size could be increased?
I was thinking of difficulty more in the sense of:
1. How unreasonable or insane was the size constraint I gave considering the VAS etc
2. The personal embarrassment I risked bringing it up.
Yes, that Cast AN 10in is looking pretty clever indeed. You know, with it's ample LF and HF response - I considered it sealed or aperiodic for the role of the 8in driver in a pair of mains featuring your 15 + 8 suggestion since then it would make an ideal matched timbre HT center on it's own. (Especially if I could nudge it towards an aperiodic roll-off of 80Hz as sealed I could only figure out an F3=97.75, Fc=80.85 and Qtc=0.6 at 34 liters.)
And thank you for your post on my new thread: How much can you add to a single driver design before risking its unique qualities? I appreciate how well it was on target and I hope it will help set the tone for other responders that follow. If you don't mind some very temporary duplication for a post or two, for the benefit of other newbies, I might ask you similar things in both threads.
Actually, it was your earlier suggestion to me below that inspired my starting it. I thought it was a very interesting solution indeed for the constraints I first stated: low volume weight/presence. I assume you were referring to the woofer sealed, but I imagine the 8in could be sealed for additional excellence in the midrange clarity needed in HT.
I'm not sure, now, in which thread it's best to ask you but might a crossover at 500, or 400, be just low enough to be minimally distinguishable from a crossoverless design? (This is just where I need that HT weight.) And secondly, again because it would only serve a very narrow and low freq range, would such a woofer only minimally impact the single source virtues like coherence of the single driver experience?
-jerry
I was thinking of difficulty more in the sense of:
1. How unreasonable or insane was the size constraint I gave considering the VAS etc
2. The personal embarrassment I risked bringing it up.
Yes, that Cast AN 10in is looking pretty clever indeed. You know, with it's ample LF and HF response - I considered it sealed or aperiodic for the role of the 8in driver in a pair of mains featuring your 15 + 8 suggestion since then it would make an ideal matched timbre HT center on it's own. (Especially if I could nudge it towards an aperiodic roll-off of 80Hz as sealed I could only figure out an F3=97.75, Fc=80.85 and Qtc=0.6 at 34 liters.)
And thank you for your post on my new thread: How much can you add to a single driver design before risking its unique qualities? I appreciate how well it was on target and I hope it will help set the tone for other responders that follow. If you don't mind some very temporary duplication for a post or two, for the benefit of other newbies, I might ask you similar things in both threads.
Actually, it was your earlier suggestion to me below that inspired my starting it. I thought it was a very interesting solution indeed for the constraints I first stated: low volume weight/presence. I assume you were referring to the woofer sealed, but I imagine the 8in could be sealed for additional excellence in the midrange clarity needed in HT.
I'm not sure, now, in which thread it's best to ask you but might a crossover at 500, or 400, be just low enough to be minimally distinguishable from a crossoverless design? (This is just where I need that HT weight.) And secondly, again because it would only serve a very narrow and low freq range, would such a woofer only minimally impact the single source virtues like coherence of the single driver experience?
-jerry
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