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In the Forum: Horn-Loaded Speakers
In the Thread: Good midbass is complicated, if not unobtainable.

Post Subject: TH design priciplePosted by Jorge on: 9/30/2013

Skushino. Yes TH is designed to play 2 octaves and no more, this derives from the design which actually uses a labrynth, in the shape of a horn, to return (and amplify) the back wave of the driver to the front and add its strenght to the output, now on phase, of the front wave of the same driver. Of course it can be stated that a time delay might be introduced though, but not too noticeable at this low ranges. In order to make the back wave come around to the front one designs a specific lenght for a specific frequency: For example, your 20 hz TH would be designed for a 40 hz wave to go around, and it would be usable from 20 hz to 80 hz, one octave below and one above, before terrible distortions begin to wreak the front wave. This is why fourth order Xovers are necesary as Low pass and High pass at these frequencies. Using a TH beyond this range is not reccomendable. You cannot change these frequencies without changing the lenght.
Now if you design a TH for 70 hz, you can use it from 35 hz up to 140 hz, and that could match up to your 142hz front Upper Bass horn.
With this solution you completely eliminate the need for a Folded horn midbass channel, that was my point since the begining.
Either lower you Upper bass solution with a bigger horn to play down to 100hz or raise your bass solution to play 140 hz.
But, of course you can make the folded horn and tell us how it sounds! I would be very interested.

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