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NEW PURIFI 8'' MWoofer [PTT8.0X04]

Adi777

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DIYers, how about the design a'la Revel Salon Ultima 2, but with Purifi transducers?
 

sarumbear

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OWC

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DIYers, how about the design a'la Revel Salon Ultima 2, but with Purifi transducers?
If we are talking about a non-compromise approach anything else than a 2-way monitor plus a multi-sub setup is a to much of a compromise in my books.

So having some big multi-way system just doesn't make any sense, even less so without a proper waveguide, unless your room acoustics are really really good.
Unless the woofers are purely doing the lower frequencies and are basically just a subwoofer in the same cabinet.
Although visually that would be a compromise for many people. A couple of subwoofers can be just made small and practically invisible.
 
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OWC

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Huge Open Baffle?
That's also possible, matter of taste at that point.

But going for open baffle for the lower frequencies doesn't make a whole lot of sense.

It most certainly helps, but still won't be able to get rid of all room modes.
Since they don't have a cabinet, the distortion caused by the (asymmetrical) compliance from the cabinet doesn't exist.
On the other hand, the efficiency of an open baffle is so extremely low due to the cancellation, this advantage is basically gone because of the much higher output power as well as the much higher cone excursion.

Especially compared to corner subwoofers, it's not a match in output power.

The asymmetry in a closed cabinet caused by the compliance of the cabinet, is mostly even order distortion, while an (much) higher cone excursion often results in odd order distortion.
Higher excursion also creates more inter-modulation distortion.
 
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Adi777

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That's also possible, matter of taste at that point.
I hope that I will be able to invite one person to listen to his large open baffles. I'll have a point of reference. You probably can't get better with OB than his speakers.
 

sarumbear

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sarumbear

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Huge Open Baffle?
I think his chart was measured on an open baffle. The drivers Qt is 0.34, as it can be seen that response is -12dB at 30Hz. You need to boost the power 8x to reach -3dB. Do you expect the distortion to stay as low as it’s shown?
 

sarumbear

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OWC

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Adi777

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I think his chart was measured on an open baffle. The drivers Qt is 0.34, as it can be seen that response is -12dB at 30Hz. You need to boost the power 8x to reach -3dB. Do you expect the distortion to stay as low as it’s shown?
I don't have idea, because I don't have experience. His OB have 8x 18 inch AE Dipol and 8x 12 inch AE Dipol. If I good remember these OB have 14Hz with -3 or -6dB.
 

OWC

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I think his chart was measured on an open baffle. The drivers Qt is 0.34, as it can be seen that response is -12dB at 30Hz. You need to boost the power 8x to reach -3dB. Do you expect the distortion to stay as low as it’s shown?
Linkwitz has a simple calculator on his website to calculate the difference between a normal closed box vs dipole.

The output of a subwoofer against the wall will be much higher, even (much) better for a subwoofer in the corner.
We are talking about at least 6-12dB which is already half the amount of excursion or more.
(or double for a dipole).
 

voodooless

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You spend all your cash on your Kef wall.. so priorities I guess… It’s cheaper than the equivalent number of Purifies though, isn’t it. On the other hand, so many subs distributed in a room will probably give you very smooth low end response.
 

OWC

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I don't have idea, because I don't have experience. His OB have 8x 18 inch AE Dipol and 8x 12 inch AE Dipol. If I good remember these OB have 14Hz with -3 or -6dB.
Having a dipole that low doesn't make any technical sense at all.
Below the first room mode there are no benefits anymore, the whole room basically becomes a pressure chamber.
 
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