So here’s a test that may interest some AND a question for those here with more experience with big cones than I have. Apologies in advance for the long-winded explanation.
I’ve been paring a 96db 12 inch pro woofer from parts express to a homemade planar in a smallish baffle 21 wide by 30 tall. The planar is about 12 inches square and with Fs set at 150 hz it is solid from about 200 hz on out to 20K. Some trap and rake work to get a level response. I find the best crossover for this setup is 18db at 300 hz on the woofer and 6 db on the planar. Lower crossovers did sound better in some ways particularly on the woofer BUT the planar is getting weak and stressed down there, so I landed on 300hz
However after much listening and playing with cross points it seemed to me that the woofer may not be quite up to the clarity of the planar in the midrange. It just didn’t seem as clean as the planar and there was some hardness on some male voice and some muddy blurry sound on some drum decay. Things were better with lower crossover points BUT the planar is weak down there.
So I did some measurements on the woofer and I see an ugly “tail” in the CSD plot in the crossover region despite smooth FR through this range. (See the tail in attached pics CSD between 300 and 700 hz). At this point I thought it would be great to have a woofer that didn’t exhibit this trait to do more listening test and see if it really matters.
I had two thoughts. 1- a woofer that behaves more like a piston through this region like an exotic honey comb cored skinned thing or maybe an aluminum cone unit ? OR, 2- is it simply that I just need a higher quality and more refined woofer?
After looking, I find that I cannot answer the question on a standard woofer that’s simply more refined. The data is not available. AND I find that exotics like skinned honeycomb or aluminum are rare and expensive and a bit lacking in wanted sensitivity.
So I decided to do a crude brut force test and just make a “piston” myself. I have some experience making foil skinned foam cored “bricks” ha, similar to what was done years ago by KEF I believe. Although my example is hardly to their standard, they do easily exhibit piston like behavior through the region im concerned with here. So, I shaped some polystyrene foam with a combo of cheez grater and the 12 inch PE cone lined with 80grit sand paper strips as the finishing work. See pics for a good laugh. This gave me a solid wedge of foam that fit snugly into the 12 inch cone. From there I sprayed the foam with adhesive (3M super 77) and skinned it with .001 inch thick Al foil, then sprayed the cone and wedged the thing in. Perfect fit.
Sure enough the “tail” in the CSD plot between 300 and 700 hz was gone. Sensitivity took a 4 db hit but I compensated for that by padding down the planar.
Now I almost wished I didn’t do this because it sounds noticeably better than the stock 12 inch woofer and the result was exactly as I had hoped. Everything in the midrange sounds cleaner and more believable, more real sounding. Piano is more convincing, male voice hardness was noticeably better but not completely eliminated, the decay of drum hits went from muddy blurry to sounding real and tuneful. Good stuff
I say “almost wished I didn’t do this” because of course once ya hear it you have a hard time settling for what ya had and now Im on a mission to either make my own skinned foam core cones ( something lighter than simply shoving in a big plug as I did) OR, I hope get an answer from someone here with more experience with big cones to convince me that I really only need a better quality standard paper cone woofer.
So after all that my question is this….. Do the more expensive but standard build woofers like the B&C or the Eminence for example move through this area (300-700 hz) with usefully less energy storage than these 12 inch pro parts express woofers do? I would much rather buy than go on the long development process of making a light foil skinned cones similar to what LEAK did years ago.
Perhaps there is someone here that has enough experience comparing and or measuring different big cones and may know what performs through this region usefully better than the humble parts express units ??
Spending a small fortune buying 3-4 pairs of higher quality woofers is just not in my budget so anyone with real knowledge here would be truly appreciated!
I’ve been paring a 96db 12 inch pro woofer from parts express to a homemade planar in a smallish baffle 21 wide by 30 tall. The planar is about 12 inches square and with Fs set at 150 hz it is solid from about 200 hz on out to 20K. Some trap and rake work to get a level response. I find the best crossover for this setup is 18db at 300 hz on the woofer and 6 db on the planar. Lower crossovers did sound better in some ways particularly on the woofer BUT the planar is getting weak and stressed down there, so I landed on 300hz
However after much listening and playing with cross points it seemed to me that the woofer may not be quite up to the clarity of the planar in the midrange. It just didn’t seem as clean as the planar and there was some hardness on some male voice and some muddy blurry sound on some drum decay. Things were better with lower crossover points BUT the planar is weak down there.
So I did some measurements on the woofer and I see an ugly “tail” in the CSD plot in the crossover region despite smooth FR through this range. (See the tail in attached pics CSD between 300 and 700 hz). At this point I thought it would be great to have a woofer that didn’t exhibit this trait to do more listening test and see if it really matters.
I had two thoughts. 1- a woofer that behaves more like a piston through this region like an exotic honey comb cored skinned thing or maybe an aluminum cone unit ? OR, 2- is it simply that I just need a higher quality and more refined woofer?
After looking, I find that I cannot answer the question on a standard woofer that’s simply more refined. The data is not available. AND I find that exotics like skinned honeycomb or aluminum are rare and expensive and a bit lacking in wanted sensitivity.
So I decided to do a crude brut force test and just make a “piston” myself. I have some experience making foil skinned foam cored “bricks” ha, similar to what was done years ago by KEF I believe. Although my example is hardly to their standard, they do easily exhibit piston like behavior through the region im concerned with here. So, I shaped some polystyrene foam with a combo of cheez grater and the 12 inch PE cone lined with 80grit sand paper strips as the finishing work. See pics for a good laugh. This gave me a solid wedge of foam that fit snugly into the 12 inch cone. From there I sprayed the foam with adhesive (3M super 77) and skinned it with .001 inch thick Al foil, then sprayed the cone and wedged the thing in. Perfect fit.
Sure enough the “tail” in the CSD plot between 300 and 700 hz was gone. Sensitivity took a 4 db hit but I compensated for that by padding down the planar.
Now I almost wished I didn’t do this because it sounds noticeably better than the stock 12 inch woofer and the result was exactly as I had hoped. Everything in the midrange sounds cleaner and more believable, more real sounding. Piano is more convincing, male voice hardness was noticeably better but not completely eliminated, the decay of drum hits went from muddy blurry to sounding real and tuneful. Good stuff
I say “almost wished I didn’t do this” because of course once ya hear it you have a hard time settling for what ya had and now Im on a mission to either make my own skinned foam core cones ( something lighter than simply shoving in a big plug as I did) OR, I hope get an answer from someone here with more experience with big cones to convince me that I really only need a better quality standard paper cone woofer.
So after all that my question is this….. Do the more expensive but standard build woofers like the B&C or the Eminence for example move through this area (300-700 hz) with usefully less energy storage than these 12 inch pro parts express woofers do? I would much rather buy than go on the long development process of making a light foil skinned cones similar to what LEAK did years ago.
Perhaps there is someone here that has enough experience comparing and or measuring different big cones and may know what performs through this region usefully better than the humble parts express units ??
Spending a small fortune buying 3-4 pairs of higher quality woofers is just not in my budget so anyone with real knowledge here would be truly appreciated!
Attachments
Would 4 six inch drivers give you the same surface area, but have pistonic behavior though the frequency range?
Cool idea though. I wonder if some expanding foam left in a speaker (sat on its magnet) would self level.
Cool idea though. I wonder if some expanding foam left in a speaker (sat on its magnet) would self level.
If you want advice for a higher quality woofer.
Specify which 12" you have now.
Desired range from xx to 300.
And sensitivity / desired volume levels.
Specify which 12" you have now.
Desired range from xx to 300.
And sensitivity / desired volume levels.
Im sure they would BUT now your into very low impedance if all in parallel and in my experience series parallel combos don't work well. A 16 ohm version would come to 4 ohm if anyone made such a thing but likely limited X max and I would really like to stay at 8 ohms
expanding foam that comes in the can at the hardware store is very soft, not really up to this task and doesn't level out but could just shave it off level. However I think there are expanding urethanes that come in a two part mix which is much harder and unfortunately denser and heavy. Ultimately If I want to move in this direction it will be learning how to fab actual cones to get the moving mass down somewhere close to standard cone. Dont really want to go there but.......
"If you want advice for a higher quality woofer.
Specify which 12" you have now.
Desired range from xx to 300.
And sensitivity / desired volume levels."
As mentioned Im presently using a Parts Express 12 inch Pro woofer
I would like it to be a 15 ich OR even an 18 inch, I believe if 15 inch will need about 10mm X max but less if an 18?
the woofer must traverse the region of 300 - 700 better than the PE woofer as explained in my original post
Sensitivity needs to be close to 96 db/watt give or take a db or 2
It will be crossed over at 18 db oct at 300 hz in open baffle. not concerned about getting really deep BUT suspect an Fs around 40 hz +- 5 would serve well in my application. I can modify suspensions to get a higher Fs IF a proper cone has a really low Fs like 15-20 wich will likley be trouble in my application
Specify which 12" you have now.
Desired range from xx to 300.
And sensitivity / desired volume levels."
As mentioned Im presently using a Parts Express 12 inch Pro woofer
I would like it to be a 15 ich OR even an 18 inch, I believe if 15 inch will need about 10mm X max but less if an 18?
the woofer must traverse the region of 300 - 700 better than the PE woofer as explained in my original post
Sensitivity needs to be close to 96 db/watt give or take a db or 2
It will be crossed over at 18 db oct at 300 hz in open baffle. not concerned about getting really deep BUT suspect an Fs around 40 hz +- 5 would serve well in my application. I can modify suspensions to get a higher Fs IF a proper cone has a really low Fs like 15-20 wich will likley be trouble in my application
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The closest that i know to your wanted specs is the Faital 15HF530 (8ohm version). Maybe some of Acoustic Elegance will also fit (but they are hard to get with little info about them public). All those are not cheap altough.
yea thats what Im thinking BUT it sure would be nice if we could get some energy storage data from these manufactures. Seems to me with all the work Ive done personally with developing ribbons that that info is critical to getting top class sound AND it seems from my experience here the same is true. That darn PE woofer had a very smooth response BUT as stated its sound was questionable and the elimination of the stored energy in the 300-700hz range took it to another level
Also maybe someone here knows, but it seems to me that ALL the more "pistonic" woofers have a rising response up to where they go off with a bang. They dont seem to have a level response but a gently rising response until they get to the sharp peak. Isnt that riseing response the textbook response of a pure piston? AND if the cone exhibits a level response rather than a rising response isnt it because all the mechanical properties of the cone have been manipulated around well damped resonances and thus will have stored energy in the CSD?
I suppose the impedance plots we see advertised with these cones would be a heads up?? to what Im talking about here BUT so many are graded such that its hard to see with any resolution whats going on. I have noticed now that im looking that sure enough the exact area im talking about often show wiggles in the impedance curve right in this area.
I have built many larger planar bass units and they all show this rising response similar to piston action cones and extreem clarity that just seems to be missing in "well behaved " larger woofers taken to 3-400hz.
The stock PE cone I used has a level response BUT the foil skinned unit has a gently rising response on axis up to point where it rings hard around 2khz.
Seems to be any cone that has a level response cannot be piston action?
I suppose the impedance plots we see advertised with these cones would be a heads up?? to what Im talking about here BUT so many are graded such that its hard to see with any resolution whats going on. I have noticed now that im looking that sure enough the exact area im talking about often show wiggles in the impedance curve right in this area.
I have built many larger planar bass units and they all show this rising response similar to piston action cones and extreem clarity that just seems to be missing in "well behaved " larger woofers taken to 3-400hz.
The stock PE cone I used has a level response BUT the foil skinned unit has a gently rising response on axis up to point where it rings hard around 2khz.
Seems to be any cone that has a level response cannot be piston action?
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Parts express sellls transducers, not making them?
Can one assume that you mean the Dayton audio PA310?
So what does then account for the rising response, past the drivers mass break point (fhm) ? Because it is certainly not pistonic action.
And you should add one more factor when it comes to a drivers roll off /level response? namely Inductance and it's effect on the FR and extension.
There will be modes in the driver caused by it's diameter and geometry. Well damped might be a better solution then not.
A 15" will typically have it in the 3-450 hz range fx. Well damped or not.
Most drivers today get 0% attention in that regard in the first place. Surround coating, damping agents on cones etc. is very few that does.
Also difficult to find a lot of stored energy plots for large mid-bass/bass drivers.
Also be aware different scaling on the CSD plots, some just do to -20db some goes to -50. With enough resolution there all drivers will have stored energy.
The first hint would be the impedance curve, it is usually visible.
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Not that hard.
Data-bass review and forum =TD15M and TD18H. (Some info have been removed due to his TD18 issues/bad experience etc).
Justdiyit has measurements of the TD15M. https://www.justdiyit.com/acoustic-elegance-td15m/3/
The TD15X has been measured by Hificompass , just under the previous name Lambda.
Augerpro has measurements of TD12M and TD15X, Dipole,IB etc in his Drivervault, might have to go through archive
FX: https://web.archive.org/web/2020103...e.com/site/drivervault/driver-measurements/15
Acoustic Elegance forums has measurements, again go through Archive.org to dig.
And so on.
If the OP is focusing on clean decay in the normal band, hes better served looking at a well damped driver, but that brings him to exotics like TAD, Fostex and JBL etc.
thanks Arez
yes dayton audio PA310
sounds like the issues in the 300-600 hz range are in every large woofer and that well damped is the practical way to deal with them but most cones simply not refined in this respect?
Here is a glass skinned honeycomb cored 15 inch cone that I assume is attempting to avoid trouble in this area
https://www.madisoundspeakerstore.c...stics-sb42fhcl75-6-15-fiberglass-cone-woofer/
I assume similar approach with LEAK and KEF with their Al foil skinned foam cored woofers years ago?
I have not heard any good ones yet and have always been surprised by the attraction to the 2 way monitor with a compression driver crossed at 700-1Khz. Seems to me trouble in the area 300-600hz on the big cones is a poor match to the compression drivers performance? Is it simply that I have no experience with a "well damped " cone in these designs?
yes dayton audio PA310
sounds like the issues in the 300-600 hz range are in every large woofer and that well damped is the practical way to deal with them but most cones simply not refined in this respect?
Here is a glass skinned honeycomb cored 15 inch cone that I assume is attempting to avoid trouble in this area
https://www.madisoundspeakerstore.c...stics-sb42fhcl75-6-15-fiberglass-cone-woofer/
I assume similar approach with LEAK and KEF with their Al foil skinned foam cored woofers years ago?
I have not heard any good ones yet and have always been surprised by the attraction to the 2 way monitor with a compression driver crossed at 700-1Khz. Seems to me trouble in the area 300-600hz on the big cones is a poor match to the compression drivers performance? Is it simply that I have no experience with a "well damped " cone in these designs?
Looks clean enough?
Very consistent all the way to 1k.
Its well damped, paper pulp with a thick 'epoxy' coating, with coated/damped surround, also the surround is not 100% round etc.
Not to everyones liking though.
It's alnico "brothers" behaves slightly better.
Rohacell core fx makes it stiffer, but the higher breakup mode will generally also be larger in amplitude.
Your suggested SB42 was measured by hificompass.com, find info there.
Stiffer cone then paper, higher breakup freq around 900-1k, but there are secondary resonances carrying downwards.
excellent but outside my pay grade ha
thanks for your help Arez
I think I have what I need now to move forward
thanks for your help Arez
I think I have what I need now to move forward
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