Adire Audio

[ThomasW]

Here are the current "specs" from Dan Wiggins after the DUMAX testing of the 15" "Tempest"

Fs: 18.6 Hz
Qes: 0.40
Qms: 6.3
Qts: 0.377
Vas: 275L
Xmax: 17.1mm one way
Pmax: 750W
Sd: 780 cm^2

These I added from the "old" specs
Re: 2.95 ohms
Le: 1.98 mH
SPL: 88.3 dB SPL @ 1W, 1m (91.3 dB SPL @ 2.83 Vrms)


snip>>
"Basically, you'll have over 2.6L of displacement, and LOTS of power handling. We've run 1000W into the unit for the high side of an hour without a thermal breakdown (15 Hz sine wave, 100L sealed box)"

So post your design questions and models here. We'll try to optimized performance




theAudioWorx
Klone-Audio

[Patrick Sun]

Okay, Thomas, here's mine:

I think these will be my sub specs for the next Sunosub II:

I'm using 0.18 ft^3 for the Tempest driver volume displacement (am I off on this estimate?)

1 Tempest 15" driver
Tuned to 19Hz
10.2 ft^3 of internal volume
Three 4" ports (24.1" each) - vent mach 0.03
43" internal height
24" wide sonotube
3.5" of total endcap thickness (both endcaps)

Total sunosub height (w/o legs) = 46.5"

This gives me a very flat frequency response from 20-90Hz with no appreciable sloping off of the low end.

Here's the WinISD specs:

Driver : Shiva15
Project by : sun
Project for : you
--
Number of drivers : 1
Box type : Vented
Box size : 10.200 ft^3
Tuning frequency : 19.00 Hz
Vent : 3 vent(s)
24.1 in length for each
4.0 in round

Relative
Freq Gain SPL
[Hz] [dB] [dB]
20.00 -1.39 86.91
25.00 -0.35 87.95
30.00 -0.43 87.87
35.00 -0.49 87.81
40.00 -0.48 87.82
45.00 -0.45 87.85
50.00 -0.41 87.89
55.00 -0.37 87.93
60.00 -0.33 87.97
65.00 -0.29 88.01
70.00 -0.26 88.04
75.00 -0.23 88.07
80.00 -0.21 88.09
85.00 -0.19 88.11
90.00 -0.17 88.13
95.00 -0.16 88.14
100.00 -0.14 88.16
How does that look?

BTW, here's my justification on why I made the choices I made for this particular design:

The reason I'm using 24" wide sonotube is because I have a 65" section of the tube leftover from my 1st Sunosub.

I'm using three 4" vents because I don't have enough width for both the 15" driver and an 8" port. I am using 3 ports to reduce the vent mach to lessen port noise.

I'm using 10.2 ft^3 of internal volume because that's about where I get a flat response from 20-80Hz without much fanfare given the T/S specs from the Tempest driver (it seems to want "see" about 10 ft^3 of internal volume for a flat response). The F3 is around 18.5Hz (F3 = Frequency of the 3dB break point on the low end, 3dB is the half power output level). This is close to the tuned box frequency FB=19.

If I went with two 15" drivers, I'd have to go up to almost 20 ft^3 of internal volume, and that's just too large of an enclosure for me (though the added SPL would be nice).

I could compromise, keep the internal volume around 10 ft^3, and put 2 drivers in it, but my F3 would be raised to around 24.5Hz, but I'd have a higher SPL for the rest of the low end response. If I went to 15 ft^3 of internal volume, the F3 goes to 20.5Hz.

For a single 15" driver, tuning to anything lower than 19Hz didn't look too appetizing to me (based on the low end response/SPL output).

Dan Wiggins suggested I go for a FB tune of 16Hz (this helps to protect the driver from unloading under its FB/F3 ~ 15Hz, but when I plug it into WinISD, the low end response isn't too flat, it slopes downward starting around 65Hz until it gets to around 20Hz for its F3 at a consistent slope. Should I ignore what WinISD is showing me for a tune of 16Hz and go for it? This seems to be akin to a SVS 16-46 sub (though mine would be wider).

Here's the 16Hz tuned WinISD specs:

Driver : Shiva15
Project by : sun
Project for : you
--
Number of drivers : 1
Box type : Vented
Box size : 10.200 ft^3
Tuning frequency : 16.00 Hz
Vent : 3 vent(s)
35.2 in length for each
4.0 in round

Relative
Freq Gain SPL
[Hz] [dB] [dB]
20.00 -2.86 85.44
25.00 -2.18 86.12
30.00 -1.76 86.54
35.00 -1.44 86.86
40.00 -1.19 87.11
45.00 -0.99 87.31
50.00 -0.83 87.47
55.00 -0.71 87.59
60.00 -0.61 87.69
65.00 -0.53 87.77
70.00 -0.46 87.84
75.00 -0.41 87.89
80.00 -0.36 87.94
85.00 -0.32 87.98
90.00 -0.29 88.01
95.00 -0.26 88.04
100.00 -0.24 88.06

Okay, I'm done now.




PatCave; HT Pix;Gear;DIY Projects;DVDs; LDs

[ThomasW]

Hi Pat

Both the (Fb 16, F3 22.44Hz) or (Fb 19, F3 22.12Hz) look very good. Yes the Fb 16 starts rolling off earlier, but has a much slower overall roll-off curve. So I'll agree with Dan W. on this one, and say go with the Fb of 16.

BassBox 6 Pro models this as a 10.29 cu ft, with 3-4" ports 33.35" long.

I don't see any significant problems with it at all.

I haven't yet figured out how to put the graphs in a post. But both the Fb=16 and Fb=19 have very smooth roll-off plots.

I think you've got a winner here :B




theAudioWorx
Klone-Audio

[Patrick Sun]

Thanks, Thomas!

I'll see how tuning lower will affect my sub height (probably an inch or two with the longer ports).

Re: graphs - If you are able to do a screen copy and dump that into paintbrush and save it, and then convert it to a jpg, then I would think it's possible to show graphs on here using the [ img ] tags if you move them to a webpage site's storage.




PatCave; HT Pix;Gear;DIY Projects;DVDs; LDs

[Kyle Richardson]

BTW, Where did the Tempest name come from? I never heard an official nameing from Adire Audio.

Here are 2 options I am trying to decide on:
225L tuned to 20Hz or
225L tuned to 18Hz

Both have an F3 right about 20Hz but the 18Hz will roll off a little more gently. I will be putting 500 watts to this and want to prevent the driver from bottoming out. What do you guys think? The 18Hz will prevent this a little better, but I lose a little output in the 20-30Hz range. Let me know your opinions.

[ThomasW]

Pat

Thanks I know about the "post to web and img stuff", I was just being lazy and "hoping" I could "cut & paste" the plot in.

Kyle

I don't know about the derivation of the "Tempest" name. I suspect that Dan "mentioned" it in an email, since there's nothing on the Adire site that even mentions the driver.

The first info (months ago) regarding the 15" was on the "bass-list". The initial Shiva offering was posted there as well.

http://www.hayenga.com/basslist.html

The Fb 16 Hz 10.29 cu ft/291 liters looks VERY good. If you can live with an enclosure that's 1/3rd bigger. :E

If not the performance differences between Fb 18, 20 in a 225liter box are going to be small, and possibly not very audible in the real world given variations in construction techniques, and port lengths

Even if you use a lower tuning and bigger box, I wouldn't be too concerned about driver bottoming. Dan W's post about running the "Tempest" with 1000 watts for an hour with a 15Hz sine wave, pretty much says it all about power handling. So not to worry about bottoming with your 500 watt amp. :B




theAudioWorx
Klone-Audio

[KennyG]

Thomas, we might as well continue our IB discussion here.
Can you discuss the sound/output differences between this ported designs and a good IB, both true and one that's in a box, say...3 times the Vas of the drivers used. (specifically twin tempests)

[ThomasW]

Hi

Well I'll have to "guess" a little.

Before building the IB, I had 2 Audax pro 15"s in a slot loaded config. This was a sealed box and the Qtc was 0.5 This is considered "critically damped" These sounded quite good and were also a good match for the "speed" of the big ESL array.

But the "true" IB is in a league of its own. Nothing I've ever heard anywhere, at any price is it's equal. There is "detail" in the bass.

I've help some friends build to Shiva sealed "tube" subs in the last couple of months. So I have a good "reference" for that performance as well.

So to try and answer your question. If you can build at 3X Vas, you should get VERY GOOD performance. Now I'd recommend loosely filling each enclosure with polyfill. At a rate of 1 lb/cu ft. This will effectively increase the "apparent" size of each box 25%. With the 3X Vas and polyfill, you'll be approaching the 4X Vas considered "ideal" for a sealed enclosure IB.

Here are some thoughts on the construction of your boxes. Make the driver openings so that the 2 drivers can be as close together as possible. An example of this would be as if you were making a vertically standing TL where each driver was at the top of it's enclosure. Then lay the boxes down. Or make long "tubes" with the driver mounted like a standard "tube" sub. Put the tubes side by side so the drivers are as close together as possible. The result will be that they "acoustically couple" and function like one big driver. This is especially beneficical in the upper regions of the frequency band where the sub is operating.

You'll also probably want a pretty "stout" amp to drive them




theAudioWorx
Klone-Audio

[JonMarsh]

Now lets see, guys, work with me, I'm thinking that maybe four of the Adire 15" might be a good way to go for a sub for the SLAMM's.

I like the FB 16 alignment Dan is suggesting; the gradual slope roll off is an asset in my experience; indicates better transient damping, and the bass rise present in most rooms with any reasonable positioning more than compensates.
To control cone loading and get real output to at least an octave below the X1's will require strong output capabiity down to 15Hz, at least.
So, if I want to do a sub for my X1 "maxi-monitors", a 15-16 Hz tuning sounds great to me, and the extra output capability and power handling are certainly desirable to keep up with the SLAMM's. But, where oh where on earth will I put four 10 cubic foot boxes?!?!?! Each 15" cabinet will be a bit bigger than the existing X1 bass bin. This is going to start to look more like a "Greatful Dead" PA system than a home stereo! But, cone area counts, and I just can't see trying to use a "Carver Cube" to get 118 dB at 15 Hz. Neither can Carver.

Pondering my options,

Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[KennyG]

So if I read this right, Thomas you're saying the best sub-in-a-cabinet would be as follows: Twin 15's stacked on top of each other (say 1 inch apart) in a cabinet 4X Vas, in this case Vas is 550 liters, so that's a cabinet roughly 3ft X 4ft X 7ft... :E That just might fit behind my couch, but if you never hear from me again, you'll know my wife scalped me. :W

[ThomasW]

Kenny

You misunderstand about the Vas for a sealed IB using multiple drivers. For "box" modeling with standard software for a "normal" sealed of ported enclosure if 2 drivers are being used, the Vas doubles. But...............

If you goal is to reproduce a "in-a-box" IB then use 2 boxes, one for each driver. EACH box must be roughly 825L or 29 cu ft, that's 3 Vas! If you want to put both drivers in a single box, then the box size has to be 6 Vas, that's 58 cu ft. No human would be able to move this without a forklift :B

Or for something much more reasonable use the Fb 16Hz tuning discussed above that Dan Wiggins recommends. Each box (tube) is 10 cu ft. This is probably a more reasonable solution to the ("I don't want to be scalped by my wife situation")




theAudioWorx
Klone-Audio