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Quad 12" Isobaric Ported Sub
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darkmatter View Drop Down
Old Croc
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Joined: 26 February 2005
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Points: 2425 		Post Options Post Options   Thanks (0) Thanks(0)   Quote darkmatter Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2017 at 2:36pm
Originally posted by FrederikMA FrederikMA wrote:

 
Unfortunately an "ms sans serif" problem doesn't allow me to enter hornresp to get exact values and take some pics for you at the moment.

My point is that this reactive component of a manifold introducers some very interesting elements of ingeneering including driver selection.

I think you simply need to download and install the font "MS Sans Serif Regular".
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snowflake View Drop Down
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Points: 3122 		Post Options Post Options   Thanks (0) Thanks(0)   Quote snowflake Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2017 at 3:46pm
Originally posted by Elliot Thompson Elliot Thompson wrote:

Manifolds are only good to 50 Hz. That would not be classified as a Sub in this day in age.

Best Regards,


why only good to 50Hz - surely that depends on the drivers and size of box?
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FrederikMA View Drop Down
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Points: 76 		Post Options Post Options   Thanks (0) Thanks(0)   Quote FrederikMA Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2017 at 5:04pm
Originally posted by Elliot Thompson Elliot Thompson wrote:

Manifolds are only good to 50 Hz. That would not be classified as a Sub in this day in age.

Best Regards,


Void Nexus X goes to 36Hz -3dB
http://voidacoustics.com/docs/products/Nexus_X.shtml



Edited by FrederikMA - 01 August 2017 at 5:14pm
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Elliot Thompson View Drop Down
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Points: 5175 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2017 at 8:08pm
Originally posted by FrederikMA FrederikMA wrote:

Originally posted by Elliot Thompson Elliot Thompson wrote:

Manifolds are only good to 50 Hz. That would not be classified as a Sub in this day in age.

Best Regards,


Void Nexus X goes to 36Hz -3dB
http://voidacoustics.com/docs/products/Nexus_X.shtml


Where did you see it says it is a Manifold? The Manifold is a patented design from Electro-voice from the 1980's that uses 4 or 2 18-inch Drivers.


Best Regards,
Elliot Thompson
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snowflake View Drop Down
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Joined: 29 December 2004
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Originally posted by Elliot Thompson Elliot Thompson wrote:

Originally posted by FrederikMA FrederikMA wrote:

Originally posted by Elliot Thompson Elliot Thompson wrote:

Manifolds are only good to 50 Hz. That would not be classified as a Sub in this day in age.

Best Regards,


Void Nexus X goes to 36Hz -3dB
http://voidacoustics.com/docs/products/Nexus_X.shtml


Where did you see it says it is a Manifold? The Manifold is a patented design from Electro-voice from the 1980's that uses 4 or 2 18-inch Drivers.


Best Regards,



you can see the manifold mounting on the picture in the link above. I haven't read the whole EV patent but I wouldn't think they would have limited it to 18" drivers, would they? patent will have expired by now anyway.
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Elliot Thompson View Drop Down
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Points: 5175 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 01 August 2017 at 9:55pm
Originally posted by snowflake snowflake wrote:

Originally posted by Elliot Thompson Elliot Thompson wrote:

Originally posted by FrederikMA FrederikMA wrote:

Originally posted by Elliot Thompson Elliot Thompson wrote:

Manifolds are only good to 50 Hz. That would not be classified as a Sub in this day in age.

Best Regards,


Void Nexus X goes to 36Hz -3dB
http://voidacoustics.com/docs/products/Nexus_X.shtml


Where did you see it says it is a Manifold? The Manifold is a patented design from Electro-voice from the 1980's that uses 4 or 2 18-inch Drivers.


Best Regards,



you can see the manifold mounting on the picture in the link above. I haven't read the whole EV patent but I wouldn't think they would have limited it to 18" drivers, would they? patent will have expired by now anyway.

I do not see an internal picture of the design so, I am not going to assume it is indeed a Manifold. From historical standpoint, Rog tends to create his own designs (with great pride) despite from a spectator point of view it resembles another design when it comes to bass cabinets. A prime example is the PD 1850/186 and the Cerwin Vega B 36.

Best Regards,  
Elliot Thompson
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RoadRunnersDust View Drop Down
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Originally posted by Elliot Thompson Elliot Thompson wrote:

Where did you see it says it is a Manifold? The Manifold is a patented design from Electro-voice from the 1980's that uses 4 or 2 18-inch Drivers.


The EV Manifold Technology is pretty much just about considering a moving diaphragm as a piston and loading them into a Manifold so as to unify their output.

It's used on the HF and MF units from the MT series, its not solely an LF principle, nor is it restricted to 18" drivers.

Turbo did something very similar with the V2 device on the later TMS-3s... Which, amusingly, used the same HF driver as some of the MT series HF units yet achieved a much better result (at the cost of expense)
www.guildfordcablecompany.co.uk
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Contour View Drop Down
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B36 and 186 horn have different folding.
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mobiele eenheid View Drop Down
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But from a spectator view (the outside) they might look the same, which is the point Elliot is trying to make.

That being said, you can see the drivers in the central (manifold chamber), that are mounted as they would in a manifold, you can see the ports and there's only about 40 litre per driver to play with, so there isn't exactly much else you can do that makes sense. The patent has expired and he is the first to cram 8 x 12" drivers in such a small enclosure.

Let's ask Aman Gebru!
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cravings View Drop Down
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i think that was the point elliot was making. that at a glance, they might appear similar. but they're actually different.
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FrederikMA View Drop Down
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So in the search for a high cabinet size to output ratio I guess it's about finding drivers with suitable Thiele Small parameters for a small volume reflex manifold or finding drivers with higher sensitivity to compensate for the reduced sensitivity of the isobaric loading. In practice i would suspect the reflex manifold to win out on sheer output to cabinet size, disregarding the allegedly reduced distortion of some kinds of isobaric loading.
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snowflake View Drop Down
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Originally posted by cravings cravings wrote:

i think that was the point elliot was making. that at a glance, they might appear similar. but they're actually different.


I thought people were saying they didn't know what was inside (although it seems likely they are a bass-reflex with manifold mounting).
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