Subwoofer what is qtc

Recommended values for Qtc are from 0. A Qtc of 0. The diagrams below shows how to use Hornresp to design a sealed subwoofer system. Basically you enter some starting values on the "Parameters" screen and then adjust the value for Vrc the rear box volume until the combination of Qtc and response curve is to your liking.

Aaron Gilbert. Find More Posts by aaroncgi. In addition to the previous link I gave, which had the response shape at various frequencies for various values of Qtc, here is the "step response" of variious values of Qtc, and Qts in free air as well. The "step response" means one square pulse, I believe with the wavelength of the frequency of resonance. Anyway, you can see how transient response and overhang are different for different values of Qtc. The graph in the previous link I gave and this following graph will give you some idea of the tradeoffs between strong response and "overhand", "tightness", etc.

I think you should have the whole picture now. It is up to the listener to decide between how much amplitude he wants versus how little distortion and "overhang". It was reprinted in their Loudspeaker Anthology Part 1. The author is Richard Small, of Thiele-Small reknown.

Attached Images step response closed box. Believe Joe. What Grey is saying is only part of the story. With room gain a sub designed for flat anechoic response has way too much bass. You want your sub to roll off smoothlyin an amount just opposite that of your room gain. The downside is that this is often a pretty big box -- and if its your thing, won't give you the over exaggerated bass some like for their movies. Stay home. Respect the 2m bubble. Find More Posts by planet I would just like to add that research has shown the farther down the frequency scale we go, the less we are able to percieve distortions and overhang.

What is acceptable at 30 Hz might not be acceptable at Hz. Transient response and "overhang" vary with vented box alignment as well, but all of the common vented box alignments have worse step response than the Qtc. I'll be posting the step response of some common vented alignments in another thread, but not tonight. The difference is apparent. PS: I'm a vented box fan.

I like the extra output. But I think the people on this forum should be allowed to judge for themselves. Inertia said:. The higher the Qtc, the larger the resonant peak will be and the less the air in the box, as an envelope, will control the motion of the cone. Heavy things accelerate more slowly than light ones, so the voice coil and magnet assembly are designed accordingly.

Air compresses, but the cone's movement has less of an effect on a large volume than on a small one it's not compressing as much, in terms of percentage , so the air in a large box won't do as much to keep the cone from continuing to move. Everything resonates well at certain frequencies and really well at one particular frequency. For a speaker, this is the Fs. Think of bad damping as a drum with only one head. Tap it, and it keeps vibrating until it naturally diminishes but if you put a head at the other end of the cylinder, it doesn't "ring" as long.

Some music works better with a high Qtc, like Rap and Hip-Hop. Car stereos that were designed for this are sometimes called "one note wonder", because it only does one frequency really well. For the most even response and smaller peaks, more damping is better. A Qtc of. That would sound terrible for almost all other music. Transmission line and sealed box systems are generally much more neutral sounding.

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At resonance, the speaker's impedance increases dramatically. The speaker's impedance may go from 4 ohms to more than 20 ohms at resonance.