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Old 22nd January 2013, 12:48 AM   #1
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Default 3.5" sub in a huge box with a really large passive radiator?

How low can a high excursion 3.5" subwoofer go in this kind of box with a really powerful amplifier? (400 watt amplifier)
Not to kill the speaker but enough to drive the speaker Just under it's true limits without distorting or get too hot
And with a really large passive radiator in a big box?
How much bass could it really put out? Would you feel vibrations in your windows in your car? of course you may not see them but could you feel it?

Last edited by realflow100; 22nd January 2013 at 12:52 AM.
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Old 22nd January 2013, 01:24 AM   #2
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Maybe, if the car was inside the box, but maybe not, if the box was a lot bigger than the car.
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Old 22nd January 2013, 01:33 AM   #3
sreten is offline sreten  United Kingdom
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Hi,

I've yet to see you ask a question where you remotely understand
the consequences of the question, (nevermind taking any notice of
the answers you get), and basically you ask very obscure questions.

No 3.5" driver does 400W, period. The size of the box and the PR
is not simply a case of the the bigger the better and more bass,
it indicates your more interested in how you imagine things might
work than being interested in how they in reality actually do work.

Imagination is great, but reality bites when it comes to engineering.

The sensible maximum box size is related to driver Vas and
PR's generally only have to be double the area of the driver,
(more rigorously double the driver volume displacement).

rgds, sreten.
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Last edited by sreten; 22nd January 2013 at 01:52 AM.
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Old 22nd January 2013, 05:21 AM   #4
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Aside from the very valid points that sreten has pointed out,Maybe this online calculator can give you an idea of what kind of performance you can expect from any size driver regardless of how much power it might take,

Piston Excursion calculator

Cheers !!

jer
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Old 22nd January 2013, 05:46 AM   #5
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Location: Cascais
Quote:
Originally Posted by realflow100 View Post
How low can a high excursion 3.5" subwoofer go in this kind of box with a really powerful amplifier? (400 watt amplifier)
Not to kill the speaker but enough to drive the speaker Just under it's true limits without distorting or get too hot
And with a really large passive radiator in a big box?
How much bass could it really put out? ...
What's the size of the car to calculate room (car) gain?
Try the SEAS E0021-08S W12CY001
In a test BR box of: SEAS W12CY001-E0021-08S, VB = 40.0 L, FB = 20.0 Hz
a room gain of 10dB, F3=14Hz, máx.V=8.47 V, máx.SPL@0.50m=105.0 dB (2x drivers).
You can rock the boat...
(blue line with room/car gain)

Note: Why don't you use Bass Shakers instead?!
Aura Bass Shakers
Beyma SK07 16 Ohm Bass Shaker
Attached Images
File Type: jpg SEAS W12CY001-E0021-08S.jpg (59.3 KB, 306 views)
File Type: jpg seas-Excel-loudspeaker-woofer-4-5inch-12cm-E0021-W12CY001.jpg (7.6 KB, 301 views)

Last edited by Inductor; 22nd January 2013 at 06:10 AM. Reason: Bass Shaker
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Old 22nd January 2013, 06:30 AM   #6
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Location: Washington
Quote:
Originally Posted by sreten View Post
Hi,

I've yet to see you ask a question where you remotely understand
the consequences of the question, (nevermind taking any notice of
the answers you get), and basically you ask very obscure questions.

No 3.5" driver does 400W, period. The size of the box and the PR
is not simply a case of the the bigger the better and more bass,
it indicates your more interested in how you imagine things might
work than being interested in how they in reality actually do work.

Imagination is great, but reality bites when it comes to engineering.

The sensible maximum box size is related to driver Vas and
PR's generally only have to be double the area of the driver,
(more rigorously double the driver volume displacement).

rgds, sreten.
Any consideration or thoughts as to the legitimacy of realflow100..??
Perhaps realflow100 is just someone posing questions like these as a ruse!
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Old 22nd January 2013, 10:23 AM   #7
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i'm just asking a question to see what everyone thinks of my idea >.<
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Old 22nd January 2013, 10:29 AM   #8
mseidl is offline mseidl  Germany
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Quote:
Originally Posted by realflow100 View Post
i'm just asking a question to see what everyone thinks of my idea >.<
in my experience, you need a lot of small woofers. Not just one, more like 6.... but still 3,5" seems really small. I did hear a very good system once with 6 5" focal ws woofers in a 7th? order band pass box. but it was in a car. expensive and very elaborate. not deep by any means, but incredibly accurate.
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Old 22nd January 2013, 10:57 AM   #9
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The small driver won't excite enough air inside the cabinet to excite the PR much, and won't move enough air outside to make your windows move.

Bass needs air displacement, which is proportional to the square of the diameter, and the available excursion. A single 6 = 4x 3" drivers. You really won't get much low end out of a 3".

It'd also bottom out way before you hit 400w. The cabinet of which you speak would be so big that the driver won't "see" it much, so cone motion would go pretty much unrestricted = bottoms out with no power, like free-air.

Chris
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Old 22nd January 2013, 12:01 PM   #10
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I'm not talking a full 400 watts to it.. I mean't enough power so it runs just under it's top limits without overheating or getting slowly cooked.
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