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Old 29th July 2009, 03:35 PM   #11
GM is offline GM  United States
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FWIW, when I looked at the photos the other day I saw a rather innovatively laid out, high tuned (small front chamber) 6th order BP once secured/sealed to a surface with a pair of high Fs 'full-range' drivers to presumably add some surround ambiance and after taking a 'fresh' look just now I still believe it is. IOW, other than the layout, just another typical B@$3 alignment.

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Old 29th July 2009, 04:44 PM   #12
jbell is offline jbell  United States
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GM, I agree, it's typical B........ no highs no lows, gotta be ......

As for Chris' firebird http://www.parts-express.com/projec...roject=Firebird suggestion, that was EXACTLY what I had in mind, only using the 5 1/4" TB drivers, due to the limited height requirement.
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Old 29th July 2009, 05:22 PM   #13
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So Arno, what is your budget? Can the enclosure be any taller and still allow the top to be low enough when down? Are you a handy enough woodworker to make something shaped like the Bose unit so as to maximize the limited space you have available? While you still have it in your custody you may wanna trace its outline to a piece of cardboard, would save you some time if you do make your own unit eventually.

Just because Bose has made some new ultra high-tech 11th order NASA level enclosure y'all don't understand don't mean its time to break out the Bose HaterAde, maybe they are onto something here. I suppose it should sound good if there is any validity to my statement though.

How much was the Bose SubWoofer option new from Porsche? I wonder what they are goin for on eBay.
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Old 29th July 2009, 05:49 PM   #14
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Default Re: Please help me understand this subwoofer design

Quote:
Originally posted by jbell
GM, I agree, it's typical B........ no highs no lows, gotta be ......
OK, so are you saying you now agree that it's probably a 6th order alignment or just that whatever it is a typically performing B@$3 product?

Regardless, for a convertible/roadster, a 6th order alignment makes sense to me with 4th order, sealed, TL or TQWT a better choice overall for a typical closed in vehicle.

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Old 29th July 2009, 06:00 PM   #15
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Quote:
Originally posted by 901Fixer
I suppose it should sound good if there is any validity to my statement though.

How much was the Bose SubWoofer option new from Porsche? I wonder what they are goin for on eBay.
Yep........ The few on-line reviews I've read were mostly very negative plus the number of used units available.......... Nothing wrong with any of their system concepts IMO, just their implementation and especially their marketing strategy (my reason for trashing them every appropriate chance I get).

Dunno, I couldn't find it on-line, so was going to scope it out at the local dealer a few miles away. Didn't check fleabay, but 'make offer' ruled otherwise.

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Old 29th July 2009, 08:46 PM   #16
Nanook is offline Nanook  Canada
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Default ultimately

who cares?

the DIYsubwoofer picture is effectively the same thing as this Bose whatever you call it....

I think all can agree that almost anything else would be better implemented, and there are 4" dedicated woofers (not subs ) available at a very reasonable cost, that can provide enjoyable bass. Rear fill in a car of this type is a waste anyways...but bass isn't.

Just remember that whatever gets built (if that is the final goal for Arno), it will have completely different sounds when under the top or open air driving...
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Old 2nd August 2009, 03:11 PM   #17
Arno is offline Arno  Europe
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Sorry for my late reply, I've been swamped at work lately. Thanks to all for your replies and ideas, I really appreciate.

Two things that could be important. In the Bose box, the holes next to the woofers (red arrow) are not vents, there are sealed and are there for locking the box onto the shelf.
If the front chamber is actually vented, it is then through the 3" grills in front of the box (yellow arrow) but then the waves would have to travel through a very narrow channel (at the right of the yellow arrow) :

Click the image to open in full size.

I'm pretty sure it will be difficult to fit 5"1/2 speakers in there. I'd have to actually measure the space between the self and the roof when it's down, but I'm confident there's less than 5".

So what are my options ?

1 - Get a Bose box from eBay for 200 (Porsche sells it but the price is just silly) and find better (if possible) woofers to replace the Bose ones. This probably means finding the T/S specs of the Bose woofers, but then I'd also have to find the equipment to measure them.

2 - Make my own enclosure based on this Bose design. That was my first idea, because it allows for larger speakers than what the available height allows. But after reading your answers, it just seems too complicated for me to design.

3 - Make my own enclosure based on something else than the Bose box. I have to read more on the different ideas you already mentioned. I'll have to check if I can source the TB drivers in Europe.

4 - ???

I'm fairly good at woodworking and I've got tools, so building an enclosure, even a complicated one, is not a problem. However I realize that my knowledge is actually limited, I could design a vented box given T/S parameters, but more complicated enclosures are a challenge. I have to study more (any good pointers BTW?).

As far as budget, I'd like to keep it under 500 , else it won't pass the wife acceptance factor (this car is a money sink to her ;-). At least at first, I plan to use spare channels from my Audison amp that is already in the front trunk.

Again, I really appreciate the help.
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Old 2nd August 2009, 04:03 PM   #18
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Quote:
Originally posted by Arno
Two things that could be important. In the Bose box, the holes next to the woofers (red arrow) are not vents, there are sealed and are there for locking the box onto the shelf.
If the front chamber is actually vented, it is then through the 3" grills in front of the box (yellow arrow) but then the waves would have to travel through a very narrow channel (at the right of the yellow arrow) :

Click the image to open in full size.
Ok, that is pretty funny and probaly the source of most of the confusion here. They look more like ports/vents than any other item on the enclosure.
Since you can build something that is what I would do. Don't worry about designing it, just build whatever you like gets suggested here.
What brand of drivers are easily available to you? TangBand is great and very cost effective and all over eBay, sometimes shipped directly from China very reasonably. They definately aren't your only option though.
What will you be powering them with?
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Old 2nd August 2009, 11:54 PM   #19
Arno is offline Arno  Europe
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Quote:
Originally posted by 901Fixer What brand of drivers are easily available to you?
Major car audio brands, JL Audio, Focal, CDT, etc.


Quote:
Originally posted by 901Fixer TangBand is great and very cost effective and all over eBay, sometimes shipped directly from China very reasonably. They definately aren't your only option though.
I didn't know that brand, but I'll check it out.


Quote:
Originally posted by 901Fixer What will you be powering them with?
I currently have an Audisson LRX 4.300 with 2 spare channels that I'll use at first. If later I see that I need more power, I'll add a mono amplifier.
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Old 3rd August 2009, 06:20 AM   #20
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Default Re: Please help me understand this subwoofer design

Quote:
Originally posted by Arno
[B]
Inside the box :

Click the image to open in full size.

Click the image to open in full size.


Has anyone any clue on how this type of enclosure work?

Quote:
Originally posted by Arno
[B]Sorry for my late reply, I've been swamped at work lately. Thanks to all for your replies and ideas, I really appreciate.

Two things that could be important. In the Bose box, the holes next to the woofers (red arrow) are not vents, there are sealed and are there for locking the box onto the shelf.
If the front chamber is actually vented, it is then through the 3" grills in front of the box (yellow arrow) but then the waves would have to travel through a very narrow channel (at the right of the yellow arrow) :

Click the image to open in full size.
Arno,

1. I dont hink the 3" vent is for the bass. The 3" vent might well be for the 2.5" 'wide-range' also included as part of this system.

2. I suspect this is a variation of Bose 'wave-guide' system as used by their 'wave-guide' radio
http://autospeed.com/cms/title_The-B...2/article.html

3. Do not be constrained by the shallowness of the box. Dan Wiggins and ADI were able to design a 10" woofer that might be useable (thought the Qts seems a bit low for IB).
http://stereointegrity.com/forums/2645-post7.html

http://www.acousticdev.com/cms/index...ized&Itemid=60

Your best bet would be to fabricate a fiberglass box that is maybe a bit deeper and hence has more volume for maybe 2 6-8" woofers. Used in conjection with the W3-871, CHR70, FF85K or other such 3" wide range you should be able to produce better sound than Bose. Enjoy.

Just do not expect this system to do Trance, House, or Hip-Hop at loud volumes. For Jazz, Rock, Blues, etc.. it will do fine.
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