Tapped Horn and reactance annulling

[wonderfulaudio]

Hi,

In simple terms, what is rectance anulling?
Is it relevant in order to better design a TH?
What are parameter of a good driver for TH from reactance anulling perspective?

Thanks,
WA

 

[Bern Wansen]

Hi,

In simple terms, what is rectance anulling?
Is it relevant in order to better design a TH?
What are parameter of a good driver for TH from reactance anulling perspective?

Thanks,
WA

Search wiki for what is reactance. It is a formula that specifies a frequency range on your speakers that steals power from your amp and produces nothing after that specific range. Well, for sealed boxes with the speaker behaving more like a spring (cone suspension + air compressed inside enclosure + coil inductance and capacitance) gives a roll off with just one peak in frequency range response SPL. Horns in other hand are not smooth in freq. Response, this changes the number of peaks/ ressonace frequencies of your to more than 1. I.e you have, lets say a peak at 73Hz, another at 120Hz, another at 230Hz and so on, for horns. And sure, cases that represent abysses in all that. All these can be mathematicslly described in terms of reactance component in a trivial (or very hard to deduce) equation.
It is import yes. Just dont build a horn that gives total cancellation in the range your speaker works the best 😉

 

[GM]

The horn must ideally be hyperbolic [M or T = 0.5] and tuned to the mean [Fc] of its BW [Flc-Fhm], ergo the further away from this flare factor, the less it works, so for the typical parabolic flare used here, of marginal use.

No, just another design 'tool' for specific apps.

You need to start with a [much] higher Fs driver, making many 'sub' woofers needing to be tuned down in the single digits unless a high Qes' is used and since tuning is so far below Fs, takes a lot of power handling to get even a modest output.

Flc = Fs*Qes'/2

Fhm = 2*Fs/Qes'

Qes' = Qes + any added series resistance: mh-audio.nl - Home

GM