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Old 25th April 2004, 10:25 PM   #11
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Quote:
Originally posted by bigparsnip
Hm, 7dB down at 20 Hz does sound rather appealing, but that is starting to push towards big box teritory, once you have the volume of the two peerless units in there as well as an amp and the port tubes.

There is one Peerless XLS 10 and a 'slave' unit, no port tubes.
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Old 25th April 2004, 10:28 PM   #12
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Ah, fair point I hadn't thought about that, but is there any particular way in which the two need to ba aranged, for example, would it be posible to mount them on opposite faces of a smallish cube to give a decent result, or would this cause problems with the waves in the box and be a bit of a waste of the slave unit?
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Old 25th April 2004, 10:35 PM   #13
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Quote:
Originally posted by MikeB



It's very easy what's going wrong:
WinISD can't simulate the peerless XLS, because the XLS is designed for a passive radiator.
Using the XLS for a vented/bandpass/closed does not work !
It has an extrem low QTS.

In fact, an XLS 10 with a port tube DOES work. But since the volume is too big for a small system...

I'd suggest the Apex Jr Super 8" subwoofer. This is what the LDSG has to say about this driver: "A recent addition is the Super 8" compact subwoofer. A high-Q design well suited to sealed box or dipole mounting, it's impressed all who've heard it."
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Old 25th April 2004, 10:37 PM   #14
MikeB is offline MikeB  Germany
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I have seen a configuration with the 2 devices in opposite
directions, but it seems to be wrong.
A good example of how to implement the XLS is here:

http://www.lautsprechershop.de/hifi/bau_xa10.htm

Mike
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Old 25th April 2004, 10:50 PM   #15
SimontY is offline SimontY  United Kingdom
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Hello,

A passive radiator/slave driver gives the same result as a port, so you can model for a port - it's the same thing. Mounting it opposite to the Peerless would surely be the best option, as it will help to cancel some box movement.
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Old 25th April 2004, 10:53 PM   #16
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How on earth would you model this as a port though, as surely, just matching up the volumes of the two won't help as there is the extra suspension and mass to think about? But, looking at the link from MikeB above, I do think that the peerless is probably a bit much for my first project, and will probably build into something a bit bigger than I want (or need) as the moment, as I'm guessing you will still need a fairly large volume to get the best from the driver, even if it were mounted opposite the slave in a cubed box.
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Old 25th April 2004, 10:56 PM   #17
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Quote:
Originally posted by SimontY
Hello,

A passive radiator/slave driver gives the same result as a port, so you can model for a port - it's the same thing. Mounting it opposite to the Peerless would surely be the best option, as it will help to cancel some box movement.

I thoroughly agree. You can mount the amp module on one side, which leaves one side free (the front side?). Make sure the cabinet is well braced, considering the number of holes cut into the panels (and large holes at that ).
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Old 25th April 2004, 11:04 PM   #18
SimontY is offline SimontY  United Kingdom
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Ok, it has to mate with 'bookshelf' speakers, and it has to be small. So I'd say it ought to be sealed, for two or three simple reasons...

1 - sealed may match the quality of bass from the small speakers better than ported (passive radiator)

2 - small size suggests convenient placement which means most potential room gain, which may perhaps match the roll-off of a sealed box speaker better

3 - it's harder to go wrong, easier and cheaper (no radiator or ports to buy and fit in)

4 - it probably doesn't need the extra several dbs of spl a ported design will give

5 - sealed may be about 1/2 the size of ported (I think that's normal)
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Old 25th April 2004, 11:08 PM   #19
stee-b is offline stee-b  United Kingdom
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Have a look at http://www.bkelec.com/
They claim to have a XLS10 in an 18 litre sealed box giving -6 dB @ 17 hz

Cheers steve
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Old 26th April 2004, 06:31 AM   #20
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I recently completed a 12" sub in a sealed enclosure so far with good results.

For what you are trying to achieve an 8" driver in a sealed enclosure should work fine.

To get sub drivers to work below their resonant frequency read this http://sound.westhost.com/project48.htm , even though it applies to a 15" sub example.

As your box gets smaller you need to equalise the driver, feed it more watts and drive it harder to compensate for its natural rolloff. Using a Linkwitz Transform (LT) circuit achieves this. I have my LT PCB and will be trying it on my sub in the next few weeks.

If not an LT then choose a suitable long throw, low Fs 8" driver and model it using WinISD in the smallest sealed box that gives good response. Then put the box in the corner of your room and enjoy.

You could try modelling this driver.
http://www.adireaudio.com/diy_audio/.../adire/av8.htm
I have just used the adire DPL12 and it is great.

Howard
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