TL subs in the Attic? and Triangular Cabinets

[navin]

bass in non directional. i hear that often.. how come i can hear the subs in my car. my subs are i the trunk and I can hear the subs come on (the sub amp has a delay) after the main speakers (the 4 channel main amp delay i guess is shorter).

also in many systems (including ones that claim to be XOed at 100Hz or lower at 12db or faster) I can locate the sub quite easily.

I am not saying these systems sound bad but what I prefer is if the main speakers are full range and the bass is then augmented by a sub covering the same range as the LF of teh main speakers (Dave Wilson did this demo at the 2002 expo at the Hilton on 5ht Av. NYC - dont know if anyone of you were there - using WATT 7, Puppy and a Sub) then the sub is difficult to locate.

 

[planet10]

bass in non directional. i hear that often.

Mayb i should hace said that the waves flow over and ignore anything substantially smaller than the wavelength in question. So for the sub, it doesn't really matter if you can see the woofer cone or not.

dave

 

[ThomasW]

An externally hosted image should be here but it was not working when we last tested it.

With the design on the left there is increase risk of 'chuffing' unless the frame has 'aero' designed basket legs. The Adire DPL-12" and PE Titanic 10"/12" are such designs.

The design on the right has the potential for issues with phase cancelation given the distances between the drivers, in relation to the mains

The goal of the manifold array/plenum/outlet box is to create a high pressure zone similar to that of a compression driver. That zone should be free from obstructions

My experience with IB subs indicates that there is virtually no benefit to trying to cancel the harmonics with push/pull mounting.

When designing a IB it's important to remember that IB's are excursion limited not thermal limited when it comes to power handling. So it's necessary to use more displacement than would be needed with a typical 'box' design. 4-12's sound very good, 4-15"s make a world class sub.

Hope this helps...

Regards
Thomas

 

[planet10]

The design on the right has the potential for issues with phase cancelation given the distances between the drivers, in relation to the mains

This shouldn't be an issue at the sub-frequencies these will be used at.

The larger the driver excursion the more benefit you get from the push-push loading.

dave