* f(s)= 32.97 Hz
* R(e)= 2.63 Ohms
* Z(max)= 20.68 Ohms
* Q(ms)= 3.354
* Q(es)= 0.488
* Q(ts)= 0.426
* V(as)= 30.540 liters (1.079 cubic feet)
* L(e)= 2.80 mH
* n(0)= 0.21 %
* SPL= 85.40 1W/1m
* M(ms)= 402.80 grams
* C(ms)= 0.06 mm/N
* BL= 21.19
Dual 1.4 ohm copper coil (in series). Built this up just for the sake of using some unique softparts I had laying around. Motor is Shocker Signature Series, originally made by TC Sounds. Same slug stack as 4hp but with very tigt gap, 3" coil, and copper shorting ring. They do very well for SPL applications in car audio scene, but this seems to spec pretty well with the soft suspension and much higher MMS than I'd usually use on these.
I have it listed FS on a couple car audio forums, but nobody is biting (I have a lot of money into parts and shipping will be a big hit). I figure I could scoop up a nice plate amp and put it to other use in the meantime.
Any HT gurus here think this would do well for HT applications?
18hz tuning in 2.3 cubic foot will be interesting. I think Passive radiators are in order.
I know this basket has more than 1" of travel, so I'm figuring an inch each way with 100% of the gap full.
Thermally these coils are 4 layer 3" so continuous 1200W.... that's 1200W sine wave at 50hz, go on vacation, and they should still be functioning when you get back. Possibly a little more since the aluminum cone should conduct a bit more heat away from the coil.
Anyway, I'd say it should be about indestructible at 1200W and under. For normal types of music I'd feel confident feeding it double that.
Any passive radiator experts here? I have enough baskets, cones, spiders, and such to build up any combination of sizes I'd like. Would just need an idea of how stiff to make the suspension and how much mass to add.
EDIT *** I promise to add pics when I build a box ***
Hi hispls,
When entering you T/S parameters into Hornresp, using an Sd around 500 cm^2 the Hornresp calculated Cms is 9.30E-05 m/newton, the Mmd=244.5 gm, and so on... In other words, there may be a problem with the T/S parameters. From what I can tell with the current data a tappe horn would work nicely with this driver (Vnet=250-300L), and provide high SPls; but that's without correct T/S parameters. For a small box a sealed box with low end eq should work.
Bart's simulation does not show which T/S parameters he entered into WinISD to make it accept the driver.
As to passive radiators, I like to use Jeff Bagby's software: Loudspeaker Design Software
Regards,
When entering you T/S parameters into Hornresp, using an Sd around 500 cm^2 the Hornresp calculated Cms is 9.30E-05 m/newton, the Mmd=244.5 gm, and so on... In other words, there may be a problem with the T/S parameters. From what I can tell with the current data a tappe horn would work nicely with this driver (Vnet=250-300L), and provide high SPls; but that's without correct T/S parameters. For a small box a sealed box with low end eq should work.
Bart's simulation does not show which T/S parameters he entered into WinISD to make it accept the driver.
As to passive radiators, I like to use Jeff Bagby's software: Loudspeaker Design Software
Regards,
I just entered the numbers real quick, didn't check anything, sorry.
Too good to be true, right? 😉
Too good to be true, right? 😉
Possibly I used the wrong piston diameter in WT3 when I pulled them initially. Did another run just now using 10" dia as piston area with these results:
f(s)= 31.63 Hz
* R(e)= 2.90 Ohms
* Z(max)= 18.81 Ohms
* Q(ms)= 3.035
* Q(es)= 0.554
* Q(ts)= 0.469
* V(as)= 25.190 liters (0.889 cubic feet)
* L(e)= 2.82 mH
* n(0)= 0.14 %
* SPL= 83.47 1W/1m
* M(ms)= 362.50 grams
* C(ms)= 0.07 mm/N
* BL= 19.43
Slight varience from stretching out the suspension a bit with some play and probably a little just in innacuracy of WT3.
I have never run a horn before, but have always wanted to try. My biggest worry is the difficulty in mounting this thing. Motor alone weighs 70 pounds and you can bust up your fingers really easily trying to mount these.
Has anyone here made a horn with say 4HP motor or other ungainly sized driver?.
The best thing with WinISD is to enter particular parameters in a particular order, and let WinISD calculate the ones its wants to as it goes. WinISD is mathematically very specific (using exact maths rather than real world measurements), but entering parameters that way usually ends up in TSP's very close to the stated specs (close enough to model accurately).
I entered the parameters stated, let the software calculate SD, and used 1000 watts power and 25mm of one way xmax. Following the -6EBS design, I got 60 litres with a 15 hz tune and 1000 watts to work pretty well. The driver would remain within xmax down to 12hz (so you should get away without using a HPF) at 1000 watts, and the system would deliver about 110db in room max to about 14hz.
As for pr's, if you can choose an off the shelf pr with known parameters (Acoustic Elegance do some for example), we can model a cab. The cabs remarkably small anyway (for a -6 EBS design), so ported is probably the way to go for an LFE specific sub along the lines of an SVS Ported Ultra series type of subwoofer.
Just as an FYI, I have attached a copy of the TSPs I used. Those in blue are calculated by WinISD, and as they fall pretty close to those stated, I'd be willing to trust the sim personally.
Attachments
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Josh made a horn with a 80 pound TC Sounds LMS Ultra 5400 driver.
http://www.diyaudio.com/forums/subwoofers/189784-gjallerhorn.html
Data-Bass
I expect truth lies somewhere between measured and predicted TSP's. All in all, I think any varience will not audibly impact performance if it's < 5%
I don't see me spending a ton of money on PRs when I have a pile of baskets, spiders, cones sitting around, and can simply add fishing weights with glue to acheive desired mass. If someone can suggest a good size, relative stiffness of suspension, and mass, I'll build it myself with spare parts.
My main issue with tuning so low in 2 cube is that a port with sufficient area to be efficient and not whistle wouldn't really fit in the box. I like big port area, I wouldn't want it too narrow (height vs width ratio), and I'm not sure about having too many turns in a port? What I see is a box that could be 3.5 cubic foot gross become 6-7 cube after I fold up a port that actually tunes 2 cube down into the teens.
Dear lord!!! 😱 No way in hell I have the patience to put together something like that.
Ports are going to be difficult to implement in such a small cabinet and end up very long. pr's are probably the way to go. What I would do is look at something like the AE 18" pr's, model those, then try copy them. Your going to need at least 2 15 inch pr's IMO to get the most from this driver, or a single 18. Perhaps make the driver down firing and put a single 18 pr firing forwards? An AE 18 inch pr 1600 for example will get you to about 20hz in a 50-60 litre cab, but with very good output upto about 110db.
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Hi hispls,
The T/S parameters in Post #6 work better in Hornresp, so that's what I'll be using. Your new Sd is about the same as the TC Sounds Epic 12 (506cm^2).
I tried the numbers in Bagby's program, and used two of the TC Sounds VMP 12" as a starting point (that'll give you something to look at): TC Sounds VMP 12" Passive Radiator 293-680
The old rule of thumb PR_area = 2xSd seems to work in this case (see also: Post #10 by Moonfly). Also, I like the way Jeff Bagby integrated electronic filters into his simulation. A PR box will need a low-cut filter.
Regards,
The T/S parameters in Post #6 work better in Hornresp, so that's what I'll be using. Your new Sd is about the same as the TC Sounds Epic 12 (506cm^2).
I tried the numbers in Bagby's program, and used two of the TC Sounds VMP 12" as a starting point (that'll give you something to look at): TC Sounds VMP 12" Passive Radiator 293-680
The old rule of thumb PR_area = 2xSd seems to work in this case (see also: Post #10 by Moonfly). Also, I like the way Jeff Bagby integrated electronic filters into his simulation. A PR box will need a low-cut filter.
Regards,
Attachments
I have seen those commercially available PR's. I was really thinking about down firing the PR's and leaving the active driver for show, since I don't have any more cones as pretty as the one I used on this 12. Those fancy cones are expensive and hard to find.
Really leaning towards single 18" PR since I have a spare basket and a couple spare cones that I won't do anything else with.
I could also do 3 12" passives which are pretty cheap with the price at which I own 12" cones.
I suspect a single radiator would be optimum?
This is definitely very similar dimensions to the TC 12" aluminum cone. Quite different surround than what's commonly on their drivers. More similar to the cone on the Lightning Storm woofers (a 3hp variant made for Rockford Fosgate)
SO in your example if I made an 18" passive radiator with mass of 1600g, how stiff or soft should I try to make the suspension? Is this important? My gut tells me soft, but I haven't handled one of the production versions.
Hi hispls,
When you increase the surface of the PR you need to increase the tuning mass. As to the suspension, you need a self resonance in the PR (Fsp[Hz]) that is below the usage range of the enclosure. Usually the high mass involved with large PRs takes care of that. On the other hand the suspension has to be strong enough to support the high moving mass.
I started with the TC Sounds 18" PR in Bagby's software this time, it asks for a PR mass of 2936g. Again, note the low-cut filter.
Regards,
When you increase the surface of the PR you need to increase the tuning mass. As to the suspension, you need a self resonance in the PR (Fsp[Hz]) that is below the usage range of the enclosure. Usually the high mass involved with large PRs takes care of that. On the other hand the suspension has to be strong enough to support the high moving mass.
I started with the TC Sounds 18" PR in Bagby's software this time, it asks for a PR mass of 2936g. Again, note the low-cut filter.
Regards,
Attachments
You dont need to use a normal driver cone for the pr, not least as making it light doesnt really matter. A flat disc from MDF painted any colour you like would do the job just fine, and you would then add weight after that anyway. Ive had those pr's myself in the past, and the suspension is fairly loose, though thats probably how it feels due to the weight of a pr, you can see this in the specs for those pr's on the homepage for them. Pr's generally dont like to be fired down or up, and typically need to be kept vertical, so that means you would be restricted to having the pr on one of the cabs faces. All you really need for the pr is the basket, the surround and MDF cone, a spider, a tube on the rear of the cone to connect the spider to the cone, and your added weight. If you can employ a variable tune pr where you can alter the weight, you can experiment with your sub. AE have in the past offered that pr at upto 2100 grams.
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Wow 3KG is a lot of mass. Perhaps a stiffer suspension is in order to keep that under control (will that hurt system Q?)
I have heard of doing these with just a surround and MDF ring. I have good sources on cones with surrounds attatched, no good source on surrounds only. I do have some cones that I won't use for active drivers that are easy to spare towards the cause.
Variable tune is nice in theory, I'm not really sure what I can come up with for masses that will be easy to pop on and off. Lead disks with a hole in the center would be best as I could just add a bolt to the center of my cone (with MDF plug in there) and fix on with wing nuts. I'm leaning towards glueing on say 2KG of mass or some number that I know I'll not need less of, then having the option to add or remove some smaller pieces....need to hunt around for likely looking objects to add.
Vertical PR is a good thought. I do have some very stiff spider packs that I will probably never use, but I think that would shoot me in the foot for efficiency (why I don't use them on active drivers)
Thinking it won't be a bad idea actually. Will keep a smaller footprint that way.
I was also wondering if I'm tuning so low is subsonic filter really needed? Really how much sub 18hz material am I likely to run into?
Also consider the odds of me having more than a few hundred watts on this in the house any time soon are very slim
I just did a model with of a TL in Hornresp. f3 ~ 21 hz Total box size 2.4 cf. I think you would need to mount it "butt up", as the box is that small.
Basic Details:
S1= 350 sq cm (this is the closed end)
S3= 150 sq mm (open end)
Total length= 282 cm
Sub goes as close to the closed end as you can get.
Basic Details:
S1= 350 sq cm (this is the closed end)
S3= 150 sq mm (open end)
Total length= 282 cm
Sub goes as close to the closed end as you can get.
Footprint will still be the same because your cabinet still needs to be wide enough and tall enough for an 18 inch basket, and you will need a little clearance behind the pr for the drivers motor. This is the way I would go with a pr design though. Whether you need a HPF or not will really boil down to how low you can get your tune. For modern HT use, if your tuned higher than 15hz and listen at anything like moderate levels or more, you'll probably be best to implement a HPF.
Variable tuning with a pr is really just about altering the wieght of the pr. Some companies produce pr's that have a threaded bar in the center onto which a set of washers can be placed and bolted into position. If you measure your added mass then you can marry a specific weight to a specific tune once you measure the subs response. More weight results in a lower tune, but is more likely to push the pr to its excursion limits, so your looking for a balance.
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