Indeed it is and if Qts were anywhere as favorable for a sealed box, you'd do very well.
Its in a free air application (or infinite baffle if you prefer to look at it that way) not sealed
from what I can tell the suspension is a medium stiffness. not super stiff but not really loose. Maybe a very tiny tiny hair on the stiff side? its hard to tell but it seems pretty medium stiffness to me.
the cone material is a plastic. foam surround. and coaxial multi-way type speaker.
My idea that I wanted for these speakers is to build a large oversized sealed or ported box like 1 cubic feet or more even per speaker tuned to like 40hz for these speakers. maybe 34hz to get maximum output to these
the FS and suspension stiffness seems like its just average enough to be fine in all-around application of free air, sealed, or ported.
from what I can tell the suspension is a medium stiffness. not super stiff but not really loose. Maybe a very tiny tiny hair on the stiff side? its hard to tell but it seems pretty medium stiffness to me.
the cone material is a plastic. foam surround. and coaxial multi-way type speaker.
My idea that I wanted for these speakers is to build a large oversized sealed or ported box like 1 cubic feet or more even per speaker tuned to like 40hz for these speakers. maybe 34hz to get maximum output to these
the FS and suspension stiffness seems like its just average enough to be fine in all-around application of free air, sealed, or ported.
Last edited:
but then there would be hardly any output. I tried that with some boxes i got for these and at FULL VOLUME 10v RMS going to each speaker there was literally no bass below like 130hz completely no low end at all. 50hz was just barely there even. not impressive sounding at all and very lacking.
I removed the speaker terminals and left them hanging out of the box so theres a big hole in the box and that helped a little but still not enough airspace for them
these need a much bigger enclosure to really have any low end
I have some 4-inch speakers that actually hit hard almost like a car subwoofer down to like 45hz really good and dont even need much power because the box is tuned right and a good size to let the speakers have room to breathe
I need like at least 1 cubic feet or more to really get low end on these 6x9 speakers. too much inefficiency with just throwing more power to them. i want it to be at least halfway efficient
I removed the speaker terminals and left them hanging out of the box so theres a big hole in the box and that helped a little but still not enough airspace for them
these need a much bigger enclosure to really have any low end
I have some 4-inch speakers that actually hit hard almost like a car subwoofer down to like 45hz really good and dont even need much power because the box is tuned right and a good size to let the speakers have room to breathe
I need like at least 1 cubic feet or more to really get low end on these 6x9 speakers. too much inefficiency with just throwing more power to them. i want it to be at least halfway efficient
Speaking of efficiency, that is quite heavily tied to fs, being proportional to (fs³ * Vas / Qes) or (fs³ * Sd² * Cms / Qes) or (fs² * Sd² * Cms * (Bl)² / (Mms * Re)). (Just substituting using the formulas in the TSP article). Going by similar 8" woofer and fullrange chassis, I'd be guessing that this one may be hitting 90-92 dB / W / m with a bit of a following wind, maybe 88 without.
In a Closed Box (CB) speaker, drivers this size will require a decent amount of volume, depending on fs, Vas, Qts and desired box Q. A good-quality, low-Qts driver will require less than Vas (which tends to be on the order of 50-60 liters or so), but even then 1 cu ft (28 liters) still is on the very low end. A high-Qts driver, like most cheap ones are, may require substantially more than Vas, and I wouldn't be surprised to see 2-3 cu ft here. Ask a closed box calculator and ideally determine the required woofer TSPs for a better idea. (Damping material increases effective volume due to reduced propagation velocity, but the losses somewhat reduce efficiency as well. Hence why PA speakers tend to be rather sparse inside.) If size is not an issue, a CB speaker is not a bad DIY option due to its relatively low complexity and limited effect of internal cavity resonances (though their size means bracing / rigidity is kind of important). They are also well-behaved near walls or even corners.
Bass reflex enclosures can be made smaller with better bass level handling but also require lower Qts, besides the whole issue with their higher-order low-frequency rolloff that makes them an ill fit near surfaces or even corners - performance as designed may only be achieved floating in free air (well, on stands - this may turn out to be another viable option, assuming the added complexity of port design is not an issue). You'd think boundaries would be a common feature in speaker design software, but nope.
Some drivers have Qts so high that a sensible box Q can only be reached with an open (infinite) baffle, or not even then and it will never roll off without a bit of a resonance hump (Qts > 1). It's often the (Re / (Bl)²) term in Qes that messes them up, i.e. weak drive B*l - weak magnets, wide air gap for tolerance reasons. The ratio of moving mass Mms and compliance Cms also figures in, however (which in turn can also be expressed as ~ 1 / (fs * sqrt(Cms³) - so the lower fs and the weaker the suspension, the higher the Q). Now with Qts = Qms || Qes, you can still do one thing, and that's exploiting the 1/Rms term in Qms, i.e. making the surround very lossy. Can't imagine that's doing the efficiency much good though.
(The traditional "pecking order" of Qts requirements from high to low: open baffle > closed box > bass reflex > bandpass.)
In a Closed Box (CB) speaker, drivers this size will require a decent amount of volume, depending on fs, Vas, Qts and desired box Q. A good-quality, low-Qts driver will require less than Vas (which tends to be on the order of 50-60 liters or so), but even then 1 cu ft (28 liters) still is on the very low end. A high-Qts driver, like most cheap ones are, may require substantially more than Vas, and I wouldn't be surprised to see 2-3 cu ft here. Ask a closed box calculator and ideally determine the required woofer TSPs for a better idea. (Damping material increases effective volume due to reduced propagation velocity, but the losses somewhat reduce efficiency as well. Hence why PA speakers tend to be rather sparse inside.) If size is not an issue, a CB speaker is not a bad DIY option due to its relatively low complexity and limited effect of internal cavity resonances (though their size means bracing / rigidity is kind of important). They are also well-behaved near walls or even corners.
Bass reflex enclosures can be made smaller with better bass level handling but also require lower Qts, besides the whole issue with their higher-order low-frequency rolloff that makes them an ill fit near surfaces or even corners - performance as designed may only be achieved floating in free air (well, on stands - this may turn out to be another viable option, assuming the added complexity of port design is not an issue). You'd think boundaries would be a common feature in speaker design software, but nope.
Some drivers have Qts so high that a sensible box Q can only be reached with an open (infinite) baffle, or not even then and it will never roll off without a bit of a resonance hump (Qts > 1). It's often the (Re / (Bl)²) term in Qes that messes them up, i.e. weak drive B*l - weak magnets, wide air gap for tolerance reasons. The ratio of moving mass Mms and compliance Cms also figures in, however (which in turn can also be expressed as ~ 1 / (fs * sqrt(Cms³) - so the lower fs and the weaker the suspension, the higher the Q). Now with Qts = Qms || Qes, you can still do one thing, and that's exploiting the 1/Rms term in Qms, i.e. making the surround very lossy. Can't imagine that's doing the efficiency much good though.
(The traditional "pecking order" of Qts requirements from high to low: open baffle > closed box > bass reflex > bandpass.)
Last edited:
FWIW, IME best suited to TLs, whether round or oval, especially inverse tapered [TQWT] and mass loaded [vented] with the various Radio Shack drivers. Again though, while I have extensive experience with these types used for other than mobile audio it all ended in 2000, so working on nearly 20 yrs out of date [maybe].
GM
I have no way to measure the parameters of the speakers
plus they arent perfectly going to work in sealed or ported enclosures. allowing some small amount of air to escape out the front of the speaker where the coil gap is through the spider of the speaker from the inside of the box on the back of the cone cause of the design. they are coaxial ones and im not sure how you'd reliably test parameters on them because putting them in a box would make them act completely different because of the air escaping through the coil gap
plus they arent perfectly going to work in sealed or ported enclosures. allowing some small amount of air to escape out the front of the speaker where the coil gap is through the spider of the speaker from the inside of the box on the back of the cone cause of the design. they are coaxial ones and im not sure how you'd reliably test parameters on them because putting them in a box would make them act completely different because of the air escaping through the coil gap
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.