hey
All speakers have a "lowest point" on the frequency scale, and trying to produce frequencies below this will result in the speaker exceeding its mechanical limits (Xmax and Xmech).
This limit will be a combination of both the properties of the driver itself and also the cabinet design (air volume for reflex or horn length, compression ratio and chamber sizes, among other things, for horns)
If your only playing at extreamly low volumes it wont matter as much. It still wont produce those frequencies below its low point very well if at all, but the power will be low enogh that it does no long term damage.
When you start putting any sort of power into a speaker though you have to filter out the frequencies below this point otherwise you'll blow the speaker.
All sound systems will (or should!) have this.
Alan Star |
I guess what I am asking is ... are we not missing those very low frequencies then or does it just not really matter
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Well yes, technically your cutting out the frequencies below what the horn can safely produce, but this happens with ALL sound systems.
In general, horns will only get down to around 40 or so before they begin to become, relativly, pretty huge like the lab or Quake or a couple of others. Reflex may get down to low 30's (or maybe high 20's at a push) but wont have the same horn provided efficiency. Below these points all the frequencies are always high-passed out to save the speaker.
Alan Star |
are they somehow gained through clustering the boxes and the coupling effect created ?
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Kind of. Horn speakers, subs in particuluar, have a particuluar advantage though that you dont get from reflex ones. Until it reaches the open air, the air moving in the horn can only expand in a very limited direction (i.e. down the horn) and so is "harder" to move. This creates a bit of pressure against the movent of the speaker and acts like a spring, adding extra suspension and helping to keep the movement in check at the low end of the frequencies. How much it does this is affected, among other things, by the length of the horn and the cercrumference of the mouth.
Now, when you stack several horn speakers right next to each other, their horn outputs combine. For a small distance in front of the horn the air flow still follows (is coupled to) the path of the horn and the aparent horn length that the driver 'sees' is increased. Also, so therefore is the mouth area.
In practice, what this all means is that when the horns are stacked together you gain a length and mouth area on the horn and so a few more hertz, and can move the cut-off point of your high pass filter down a few hertz.
(I don't know the specifics of the Lab, i've never made one, thats just general for all horns.
k