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post #1 of 37 Old 08-15-2013, 04:49 PM - Thread Starter
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Hi guys,

Now that I have gotten a bit up to date with the current state of DIY subwoofer building, my first few questions are in regards to amp and impedance matching.

First of all, my new plan is to re-use my 2 HE-15 drivers in a sealed cabinet with the drivers opposing each other and in phase. I would also like to duplicate the cabinet and use my 2 Blueprint 1503 drivers in the exact same configuration. The problem is that the HE-15 and the Blueprint have different impedance/VC setups:

HE-15 - DVC @ 4 ohms each coil
Blueprint - SVC @ 4 ohms

I plan on using my Crown K2 to power them:

Stereo:
500 WPC @ 8 ohms
800 WPC @ 4 ohms
1250 WPC @ 2 ohms

Mono bridged:
1600 w @ 8 ohms
2500 w @ 4 ohms

Since each cabinet will need to be configured differently, I am trying to figure out the best way to connect the new subs to the Crown. The best I could come up with is:

wire both Blueprint drivers in parallel and connect them to one channel of the Crown - presents a 2 ohm load to the Crown - 1250 watts
wire both voice coils on each HE-15 driver in parallel (brings the load to 2 ohms for each driver) and then wire the drivers in series to present a 4 ohm load to the Crown - 800 watts

Does this make sense?

Would it be better to run the Crown in bridged mono mode and connect the 2 enclosures in series, thus presenting a 6 ohm load?

Or is there a better way?

Why am I doing this? - simply because I already have these drivers and amp, and the amount of money and effort to build a pair of boxes is minimal. I have owned and used several ported designs and a passive Radiator design, so now I want to try out sealed. And before you ask, yes, I have plenty of DSP power, so I can shape the in room response with no problems.
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post #2 of 37 Old 08-15-2013, 07:59 PM
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"Does this make sense?"

yes. different impedances on different channels is fine.

"Would it be better to run the Crown in bridged mono mode and connect the 2 enclosures in series, thus presenting a 6 ohm load?"

no, but I can't fully explain how bad of an idea this may or may not be.

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post #3 of 37 Old 08-16-2013, 05:47 AM - Thread Starter
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Great! Many thanks, LTD02! (for this and all of your help in the other thread)
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post #4 of 37 Old 08-16-2013, 06:19 AM
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Can you give us some specs for the drivers. Xmax & pe at least. I'm thinking that the HE's might be a bit underutilized w/ only 400w each. The HE box will end up ~2db down from the Blueprint box due to power. That may not be an issue, but I would want the most power going to the most capable drivers.

Also, are you sure that both drivers will have a similar q when installed in the same size box? I try to match the system q when I incorporate different drivers into the system.
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post #5 of 37 Old 08-16-2013, 07:45 AM - Thread Starter
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Thanks, nograveconcern!

Here are the specs:

HE-15

Fs: 26 hz
Qms: 6.0
Qes: .345
Qts: .326
Vas: 106.7 L
Re: 6 ohm
BL: 27.3 Tm
no: .529%
1W SPL: 89 dB
Cms: .145 mm/N
Mms: 257 grams
Rms: 7.0 kg/s
max: 35 mm
Sd: 720 cm^2
Vd: 6.5L total
PEmax: ~ 2000W

peak-to-peak excursion of 2.75”
displacement of over 6 liters

Blueprint 1503:

Original Published Specs:
Qts 0.3
Qes 0.32
Qms 7.9
Vas 132 liters
Fs 26.8 Hz
Re 3.6 ohms
Sd 804 cm^2
Xmax 25.9 mm
BL 22.1
SPL 91 dB
Pe 1000 Watts

From DUMAX report:
Qts 0.376
Qes 0.411
Qms 4.458
Vas 92 liters
Fs 25.52 Hz
Re 3.93
Sd 737 cm^2
Xmax 25.9 mm
BL 22.35
SPL 87.74 dB
Pe 1000 Watts

They look very similar to me, but I am certainly no expert. I plan on mounting all coil connections of all drivers on the outside of the box so that I can configure the drivers any way possible without having to open the box to change something. Also, my plan is to build a single box first, using the HE-15s) to see if I prefer the sound of a sealed cabinet. Right now the 2 Blueprint drivers are in rather large ported Sonotube cabinets, so I will be able to compare the new sealed box against a pair of Sonotube ported cabinets. I am hoping that I will prefer the sound, as a 22" cube is a heck of a lot smaller than the Sontube monsters, thus giving me more options for placement, as well as recovering a significant amount of real estate in my theater...smile.gif

If the experiment works out and I need another amp to power the sealed enclosures with more power, I would not mind picking up something cheap like a Behringer (iNuke or EP series) to help out.
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post #6 of 37 Old 08-16-2013, 08:47 AM - Thread Starter
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Quote:
wire both voice coils on each HE-15 driver in parallel (brings the load to 2 ohms for each driver) and then wire the drivers in series to present a 4 ohm load to the Crown - 800 watts
What happens if I reverse things - connect the 2 coils in series (brings the impedance to 8 ohms for each driver) and then wire the drivers in parallel to again present a 4 ohm load to the Crown? If I understand correctly, each driver would then get the full 800 watts, but each coil would then split the power (400 watts to each coil). Would this yield the same result?

And since you are taking a look at the specs, how do these drivers compare to the SI or Dayton drivers? These were the best of the best 12 years ago, but I'll bet a lot has changed since then. I could look at the specs on SI's and Dayton's sites, but the numbers really don't mean a lot to me. I used to judge the quality of a driver by its weight - the heavier the better. These drivers weigh in at 38 pounds each...smile.gif

Edit: Looking at the TC Sounds website (that's where the HE-15 came from), the HE-15 seems to be an ancient ancestor of the LMS-R driver they currently carry.
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post #7 of 37 Old 08-16-2013, 09:51 AM
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Quote:
Originally Posted by Bob Sorel View Post

What happens if I reverse things - connect the 2 coils in series (brings the impedance to 8 ohms for each driver) and then wire the drivers in parallel to again present a 4 ohm load to the Crown? If I understand correctly, each driver would then get the full 800 watts, but each coil would then split the power (400 watts to each coil). Would this yield the same result?
No, each driver would then get 400W if wired in parallel, each coil (4 in total) would get 200W.
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post #8 of 37 Old 08-16-2013, 10:36 AM
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Quote:
Originally Posted by Bob Sorel View Post

What happens if I reverse things - connect the 2 coils in series (brings the impedance to 8 ohms for each driver) and then wire the drivers in parallel to again present a 4 ohm load to the Crown? If I understand correctly, each driver would then get the full 800 watts, but each coil would then split the power (400 watts to each coil). Would this yield the same result?

And since you are taking a look at the specs, how do these drivers compare to the SI or Dayton drivers? These were the best of the best 12 years ago, but I'll bet a lot has changed since then. I could look at the specs on SI's and Dayton's sites, but the numbers really don't mean a lot to me. I used to judge the quality of a driver by its weight - the heavier the better. These drivers weigh in at 38 pounds each...smile.gif

Edit: Looking at the TC Sounds website (that's where the HE-15 came from), the HE-15 seems to be an ancient ancestor of the LMS-R driver they currently carry.

I would wire each HE to 2 ohms and run one off each channel of your amp. Or you can wire coils in series and bridge the amp. Same end result. If you like the result of the sealed subs then get another amp for the blueprints, or a bigger amp for the HE's and use the crown on the blueprints. I hate being amp limited. biggrin.gif

What happens if you try to add in the Blueprints running all 4 on that amp like you have in post 1 is that you end up gaining 3db for adding 2 more drivers, but losing ~2db because the HE's are getting ~1/3 the power. Net result is little to no gain.
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post #9 of 37 Old 08-16-2013, 10:39 AM - Thread Starter
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No, each driver would then get 400W if wired in parallel, each coil (4 in total) would get 200W.

Ok...basic questions:

1. If I connect 2 identical SVC speakers, in parallel, to a mono amp rated at 1000 watts, how many watts are dissipated across EACH speaker?
2. If I connect 2 identical SVC speakers, in series, to a mono amp rated at 1000 watts, how many watts are dissipated across EACH speaker?

In BOTH cases, is the answer 500 watts?
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post #10 of 37 Old 08-16-2013, 10:44 AM - Thread Starter
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Quote:
I would wire each HE to 2 ohms and run one off each channel of your amp.
Ya...that's the plan when I complete the first enclosure.
Quote:
If you like the result of the sealed subs then get another amp for the blueprints, or a bigger amp for the HE's and use the crown on the blueprints. I hate being amp limited.
What would you recommend, the iNuke 6000 or the EP4000? or something else?

Oh, BTW, the Crown K2 ratings are RMS, both channels driven. This is the best amp I have ever owned...no fans, yet barely gets warm to the touch, and it can output 1250 wpc into a 2 ohm load all day long without breaking a sweat.
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post #11 of 37 Old 08-16-2013, 10:53 AM
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Quote:
Originally Posted by Bob Sorel View Post

Ok...basic questions:

1. If I connect 2 identical SVC speakers, in parallel, to a mono amp rated at 1000 watts, how many watts are dissipated across EACH speaker?
2. If I connect 2 identical SVC speakers, in series, to a mono amp rated at 1000 watts, how many watts are dissipated across EACH speaker?

In BOTH cases, is the answer 500 watts?

You don't create watts no matter how you wire it. Each channel of the amp sees a total load and produces whatever power it is capable of at that load. That is then divided among the drivers and coils.

So the answer is 500w if both wiring combinations result in the same impedance.

If you have:

2 x 8 ohm drivers and wire in parallel to a 1000w @ 4 ohm amp each driver gets 500w.

2 x 2 ohm in series to a 1000w @ 4 ohm amp each driver gets 500w.

2 x 8 ohm is series to a 1000w @ 4 ohm amp each driver gets 125-150w.


Quote:
Originally Posted by Bob Sorel View Post

Ya...that's the plan when I complete the first enclosure.
What would you recommend, the iNuke 6000 or the EP4000? or something else?

The NU6K is -2db at 10hz. The NU3K and EP are -2 at 5hz. That would be the only neg for a sealed system with the NU6K. I do like class D for it's efficiency though.
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post #12 of 37 Old 08-16-2013, 11:04 AM
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Quote:
Originally Posted by Bob Sorel View Post

Thanks, nograveconcern!

They look very similar to me, but I am certainly no expert. I plan on mounting all coil connections of all drivers on the outside of the box so that I can configure the drivers any way possible without having to open the box to change something. Also, my plan is to build a single box first, using the HE-15s) to see if I prefer the sound of a sealed cabinet. Right now the 2 Blueprint drivers are in rather large ported Sonotube cabinets, so I will be able to compare the new sealed box against a pair of Sonotube ported cabinets. I am hoping that I will prefer the sound, as a 22" cube is a heck of a lot smaller than the Sontube monsters, thus giving me more options for placement, as well as recovering a significant amount of real estate in my theater...smile.gif

Modeled them. The HE is very similar to the SI 18 in max spl up to 80 hz. You get ~ 108db at 20hz from either one. The SI does it with less power though due to the higher sensitivity of being an 18. The blueprint is ~3 db less.

Both the HE and the blueprint model very similar in response. They should work well enough in a box of the same design. They are made to have a good q in a small box while not ever coming close to running out of excursion before exceeding PE. q of .707 is like 1.3 cu ft. I like how they graph, from an ULF efficiency perspective, in more like 3 cu ft.
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post #13 of 37 Old 08-16-2013, 12:05 PM - Thread Starter
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Thanks again, nograveconcern!
Quote:
You don't create watts no matter how you wire it. Each channel of the amp sees a total load and produces whatever power it is capable of at that load. That is then divided among the drivers and coils.

So the answer is 500w if both wiring combinations result in the same impedance.

If you have:

2 x 8 ohm drivers and wire in parallel to a 1000w @ 4 ohm amp each driver gets 500w.

2 x 2 ohm in series to a 1000w @ 4 ohm amp each driver gets 500w.

2 x 8 ohm is series to a 1000w @ 4 ohm amp each driver gets 125-150w.
Ok, now I get it. That makes sense!
Quote:
I like how they graph, from an ULF efficiency perspective, in more like 3 cu ft.
My proposed box has a net volume of ~4 cu. ft. before allowing for bracing and for the driver itself, so I will probably be pretty darned close to 3 cu. ft. Now remember that I am using 2 drivers opposing each other and in phase. Does this change anything?

Oh, and by the way, what program are you using to model this? Maybe it would be a good idea for me to pick it up?

Thanks again for your help...you really seem to have a good grasp on the concepts and particulars involved.
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post #14 of 37 Old 08-16-2013, 12:50 PM
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http://www.linearteam.dk/?pageid=winisdpro

is one option.

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post #15 of 37 Old 08-16-2013, 01:42 PM - Thread Starter
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I just downloaded and installed WinISD Pro 0.50a7 and entered the HE-15 parameters in the driver editor, but when I try to save it I get a window saying "parameter error list" and the window lists a bunch of "errors". I rechecked to make sure that I entered things correctly - like entering Vas in liters), but no go. The help button doesn't work either.

Am I using the wrong program?

Edit: Ahhh...as long I uncheck the "auto calculate unknowns" box, then I can save the data...smile.gif
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post #16 of 37 Old 08-16-2013, 01:47 PM
 
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probably just entered too many values or the wrong order.
http://gonecatfishin.net/Winisd.htm

1. Either Cone Diameter (Dd) or Effective Cone Area (Sd). These describe the physical size of the radiating surface of the driver.

2. Voice coil DC resistance (Re). This is the DC resistance of the drivers voice coil, it is what shows up when you use a multi-meter to measure it. It is NOT the drivers impedance!

3. I enter the drivers Moving Mass (Mms). This is the weight of the moving parts of the woofer.

4. BL, which is an indicator of the magnetic strength of the drivers "motor".

5. Suspension compliance (Cms) which is a number describing the compliance of the parts attaching the cone to the motor (spider and surround).

6. Mechanical damping factor (Qms).

7. Xmax
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post #17 of 37 Old 08-16-2013, 01:55 PM - Thread Starter
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Wow, that's a great guide...Thanks, JWagstaff, and thanks again to LTD02 for pointing me to the program!

I'll try again now using the guide...smile.gif

Edit: Ok, everything looks good now entering the parameters EXCEPT for the calculated Vd...I entered 35 mm for Xmax and WinISD calculated Vd = 2.52 liters. The manufacturer's specs say Vd = 6.5 liters. Is this discrepancy important?
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post #18 of 37 Old 08-16-2013, 02:11 PM
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Why don't they make drivers like the HE-15 anymore? frown.gif

This 10-20mm BS is getting old.
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post #19 of 37 Old 08-16-2013, 02:12 PM
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alternative method:

make sure all fields are clear, then
enter qes then hit tab, enter qms
hit tab a couple times and let it calculate qts
hit tab a few times to move to mms
enter mms, re, bl, le, sd, xmax, and pe
by using tab after entering each data, it will calculate what it needs to
i no longer get any conflicts
sometimes the specs calculated don't match exactly the manufacturer specs, but its only rounding type errors, so it is not material

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post #20 of 37 Old 08-16-2013, 03:10 PM - Thread Starter
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Hmmm...I need to look for a version that will run properly on Windows 7. The program ran fine at first, but now I keep getting "floating point division by zero" errors....arggghhh!

Anyway, when WinISD was running, I still got a very wrong calculated Vd no matter which method I used. There must be a better program somewhere, or at least something more up to date.

Edit: It looks like I have WinISD back up and running by running it in Win 98 compatibility mode...I'll just keep my fingers crossed that it continues to work...smile.gif

Edit again: I spoke too soon. WinISD will not run correctly no matter which compatibility mode I use...frown.gif

Edit yet again: Ok, I found a version of WinISD that seems to work perfectly! It is WinISD 0.7.0.900...MUCH better! biggrin.gif

But, I still have the Vd discrepancy, and I have a feeling that that parameter will be very important in modeling this driver.
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post #21 of 37 Old 08-16-2013, 03:50 PM
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I ran into that divide by zero error too, by setting the frequency range to start at 0hz. Pretty silly to not handle this better, but what I did was uninstall the program, then use Regedit (Windows Menu -> Run -> Regedit) to delete the records where the options settings were saved. I think I ended up just deleting all the records with WinISD references. Then after reinstalling everything was working again.
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post #22 of 37 Old 08-16-2013, 03:52 PM
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post #23 of 37 Old 08-16-2013, 03:53 PM
 
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go on their facebook page and download the newest version, it's way more up to date than the normal download link, its winisd alpha version
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post #24 of 37 Old 08-16-2013, 03:54 PM
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i'm running winisd 0.7.0.900 under windows 7 and it works fine. winisd pro under windows 7 blows up for me.

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post #25 of 37 Old 08-16-2013, 03:54 PM
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I'm using 0.7.0.9?
Not sure if it's old or new but it's the version with the white charted background.
I found the other version (alpha?) with the green and black background, kept crashing whenever I tried to open it or do random things.
This one seems to be pretty good up to date...

Edit: same as LTD smile.gif
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post #26 of 37 Old 08-16-2013, 04:23 PM - Thread Starter
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Yup, guys...found it...see my multi-edited post above...smile.gif

I now have the parameters for both the Blueprint and HE-15 drivers entered and saved properly. The only thing that still bugs me is the Vd discrepancy with the HE-15. Is this important?
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post #27 of 37 Old 08-16-2013, 05:37 PM
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glad you got it all sorted out!

what is the vd discrepancy? vd is xmax * sd * 2.

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post #28 of 37 Old 08-16-2013, 07:26 PM - Thread Starter
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I entered 35 mm for Xmax and WinISD calculated Vd = 2.52 liters. The manufacturer's specs say Vd = 6.5 liters. If I enter 6.5 liters for Vd, then WinISD calculates Xmax at 90.3 mm. Something is not right. See the list of specs in my second post.
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post #29 of 37 Old 08-16-2013, 09:37 PM
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35 mm = 3.5 cm

3.5 cm * 720 cm^2 = 2520 cm^3

there are 1000 cm^3 in a liter, so that is 2.52 liters displacement each way or 5.04 liters displacement total.

6.5 liters would require about 29% more excursion or xmax of 45 mm one way (which is 90 mm two way).

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post #30 of 37 Old 08-18-2013, 03:51 AM - Thread Starter
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Thank you, LTD02. You have confirmed that WinISD is calculating Vd correctly.

The problem, however (and the same happens with the Blueprint driver), is that, according to my research on the Web, both the HE-15 and Blueprint drivers have Vd in excess of 6 liters - this was one of the things that made these drivers so special at the time. AND the Xmax figures are also correct, so for whatever reason, the formula WinISD is using does not apply to these 2 drivers. I will not even pretend to understand why this is so, but if you search for info on the Web you will find threads talking about the high Xmax and the Vd in excess of 6 liters.

Since there is nothing I can do to correct this discrepancy in WinISD, my question is, will this discrepancy cause the program to model those 2 drivers incorrectly? Or is the discrepancy meaningless for the sake of modeling?

When I tried modeling either of the 2 drivers in a 3 cu ft sealed box, the results were horrible. F3 is around 65 hz - F10 is around 28.5 hz. If I model either of those same drivers in a ported enclosure, I can attain much better results by simply playing with the box size, port size, and port length. Outside of adding some serious parametric EQ to the sealed design, there is very little I can do to attain better low end extension.

Is this because of the Vd/Xmax discrepancy or do all sealed enclosures model this poorly?
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