Qts is one of the Thiele-Small parameters of a loudspeaker. The Qts of a speaker is the driver's Q at resonance (Fs), due to all losses. The Q is the speaker's relative damping ability, or a measure of the driver's tendancy to resonate at it's Fs (resonant frequency.)
The Qts of a subwoofer determines the type of box the speaker is best suited for. Qts < 0.30 - ported Qts = 0.30 - 0.50, use ported or sealed. Qts > 0.50 sealed
How much of a difference in Qts is there between 0.50 and 0.51? Would that 0.01 difference mean I would definitely need to use a sealed enclosure?
I purchased my subs based on SQ reviews, but I still want plenty of bass. I was planning on a vented enclosure until you sent me these numbers. Should I just forget about the ported box?
Q factors: Used to describe the driver's damping (lossiness), and is derived from the sustain time, which is the ratio of stored energy to dissipated energy. Basically, how long the cone will flutter at the resonant frequency. High Q numbers mean an underdamped driver and low Q numbers mean an overdamped driver. You can consider Q factors as the tendency to resonate at Fs.
Qms: The mechanical Q of the driver. It gives you an idea of the suspensions damping characteristics, in relation the driver's moving mass, suspension compliance, and suspension loss (damping). High Qms indicates a heavy assembly (cone, voice coil, etc) and/or a loose suspension. Opposite for a low Qms.
Qes: Electrical Q of the driver, defines how strong the motor is and how well the motor can push against its suspension and its mass. A low Qes means either the driver has a low moving mass, a really high motor force factor, or a really loose suspension. A high Qes driver indicates the opposite.
Qts: Overall Q, determined from Qms and Qes combined. It is the ratio of stored-to-dissipated energy for the entire driver, and tends to be dominated by Qes. A low Qts means a light moving mass, loose suspension, or strong motor. High Qts means a weak motor, a high moving mass, or a tight suspension. This is very important in enclosure consideration.
Try plotting your sub in WinISD to look at enclosure considerations.
jonathan... cud u look at my thread like "eperienced help for my avalanche please" or somethign like that.... id greatly appreciate it i;ll check it tomorrow.
High Qts subs are used ported only for strict SPL use. They typically have a very tight suspension, which provides a high resonant frequency and produces a very high, peaky response at and around tuning, good for SPL, bad for SQ. The descriptions above are relating to a true SQ application, where you would be getting the best results in overall damping, frequency response, and performance.