Yes, also the example in this paper, is rather extreme between a BL of 8 and 40.
In reality drivers with a similar performance, cone excursion etc are often similar.
Even more so if you want to have a nice linear BL(x) curve (which the paper doesn't take into consideration).
I don't even think that this example is practically possible for woofers with a low Fs and a decent amount of cone excursion as well?
In our example it's a difference between a BL from around 8.5 and 11.
Sure for anything else that you use above Fs, it's obvious.
But that was obvious to begin with?
All other things equal, which in reality they never are.
In reality drivers with a similar performance, cone excursion etc are often similar.
Even more so if you want to have a nice linear BL(x) curve (which the paper doesn't take into consideration).
I don't even think that this example is practically possible for woofers with a low Fs and a decent amount of cone excursion as well?
In our example it's a difference between a BL from around 8.5 and 11.
Sure for anything else that you use above Fs, it's obvious.
But that was obvious to begin with?
All other things equal, which in reality they never are.
Raising BL lowers GD in the LF as well, strengthens Qes, thus increasing damping but no loss in LF efficiency. Consequence of increased filter? Thats a consequence?
27BL above vs 270BL below
Le will change the start up transient performance but the effects are not as drastic as some describe.
0Mh above and 10mh below.
And finally 100mh
27BL above vs 270BL below
Le will change the start up transient performance but the effects are not as drastic as some describe.
0Mh above and 10mh below.
And finally 100mh
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BL, mass, and Le are now, not very meaningful...We can just look at frequency response and Q... My ideas about mass and distortion vs spl are really issues of rigidity and inertness of the cone, Until we get inside the enclosure, where BL faces new mechanical resistance, and the Higher BL to mass ratio, stays truer to the Free air performance than the low BL driver. Send it???
Why do I feel like it makes sense that the higher a drivers HF extension, the better it can handle multiple frequencies well below the HF cutoff? HF extension is a show of force, of potential max resolution.... complex signal is the challenger of the drivers capability of said resolution, No? Like, the higher a driver can play, is saying, I can play this many oscillations per second. Going from a single frequency and then adding more frequencies, isn't this the same as asking of more oscillations per second from the driver? For example....Can we not say that a driver that is playing 20hz, 200hz, 2000hz, and 20khz, is being asked of 22220 oscillations per second? A driver playing from 50hz to 60hz is playing at least 605 different oscillations?
Yeah I guess that way of thinking gets Flawed by excursion.... but do you get the direction of my thought train? is there some truth to what Im describing.
Why do I feel like it makes sense that the higher a drivers HF extension, the better it can handle multiple frequencies well below the HF cutoff? HF extension is a show of force, of potential max resolution.... complex signal is the challenger of the drivers capability of said resolution, No? Like, the higher a driver can play, is saying, I can play this many oscillations per second. Going from a single frequency and then adding more frequencies, isn't this the same as asking of more oscillations per second from the driver? For example....Can we not say that a driver that is playing 20hz, 200hz, 2000hz, and 20khz, is being asked of 22220 oscillations per second? A driver playing from 50hz to 60hz is playing at least 605 different oscillations?
Yeah I guess that way of thinking gets Flawed by excursion.... but do you get the direction of my thought train? is there some truth to what Im describing.
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Well, as I noted here, Le govern's the driver's transient response, so the wider its BW, the better controlled it is in theory, ergo the higher it can be XO'd or use a lower order.
This is no different than we perceive a wider/fuller BW the lower its fundamental; this really becomes obvious when tuned really low and in HT can really make those Dinosaurs a bit too real for many children and some adults IME after tuning down to ~14 Hz.
There use to be a local on the forums whose wife is (was? decades ago now) Atlanta Symphony's 1st chair violin and he tried everything from a small 4"? 'FR' driver BLH to OBs, et al, to make as near as 'close enough' replica of her practicing, but it took a 6 Pi corner horn woofer (bottom cab) with the little 4"? (naturally rolled off above ~8 kHz) in a sealed cab mounted at his wife's seated ear height (she) deemed it a true replica even when playing as hard/loud as she could, the 'stumbling block' of his previous designs.
Anyway, some 'food for thought' re my goal of 'Is it live or is it Memorex'.
This is no different than we perceive a wider/fuller BW the lower its fundamental; this really becomes obvious when tuned really low and in HT can really make those Dinosaurs a bit too real for many children and some adults IME after tuning down to ~14 Hz.
There use to be a local on the forums whose wife is (was? decades ago now) Atlanta Symphony's 1st chair violin and he tried everything from a small 4"? 'FR' driver BLH to OBs, et al, to make as near as 'close enough' replica of her practicing, but it took a 6 Pi corner horn woofer (bottom cab) with the little 4"? (naturally rolled off above ~8 kHz) in a sealed cab mounted at his wife's seated ear height (she) deemed it a true replica even when playing as hard/loud as she could, the 'stumbling block' of his previous designs.
Anyway, some 'food for thought' re my goal of 'Is it live or is it Memorex'.
Well, the driver is launching them off different areas in a ~pistonic way up to the VC frequency, then in seeming random TL modes based on the diaphragm's design, materials, coatings and finally all the HF that 'fits' on the dustcap is ~pistonic, so wouldn't think it had hundreds of oscillations or seems like it would have an underlying hum to it.
Is that for sure? It seems higher Bl (assuming same Re) creates higher and more reactive electrical impedance with broader peak around resonance. So higher Bl not reduces LF efficiency, just creates a different electrical impedance and actually increases LF efficiency.
Just compare the data of 2 similar woofer, one with relative low motor force (high Qts) and one with higher motor force (lower Qts), the electrical impedance of the lower Qts driver is higher in the LF region around resonance despite the fact it have lower Re:
http://www.dibirama.altervista.org/...vox-380-2000ob-woofer-15-8-ohm-1200-wmax.html
http://www.dibirama.altervista.org/...aital-15pr400-8-woofer-15-8-ohm-800-wmax.html
We've discussed this.. it's no different to signals on a cable, this time it's cone position rather than current magnitude.
Question.... Is Le the final say or is it the impedance plot? I ask because I find woofers with low Le that have impedance rise sooner than another driver with higher Le.
This driver has an Le of 1.8mh but yet impedance rise is not bad, crossing 20ohms at 5k... Scrolling through the 21" woofers on the database, a 21" with le lower than 1 is not a thing... How does Le and Diameter play together?
This driver has an Le of 1.8mh but yet impedance rise is not bad, crossing 20ohms at 5k... Scrolling through the 21" woofers on the database, a 21" with le lower than 1 is not a thing... How does Le and Diameter play together?
Le – Voice coil inductance, in millihenries (mH), typically measured at 1 kHz for woofers. So this parameter is given by the physical properties of the coil. The real measured impledance is what matters - you can see unwanted resonances there and it interacts with passive crossover components.
Checking different diameter (membrane aera) woofers with the same voice coil and magnet construction, the larger one always have higher Le.
Le as used in specs is an approximation. In the real word the VC inductance is not a constant value but varies with frequency. There are several different models to approximate this effect. The only importance for Le IMO is in a passive crossover. For active or very LF X-overs it does not play a significant part.
I think that I agree with you, but the verbiage around here is so loose that it's hard to tell what is being claimed. People use "efficiency" when they mean "sensitivity", and visa-versa, and may not even know the difference.
Okay, I'm not sure about that the same motor but larger cone leads to higher Le, probably was a too early call.
I agree, this can be misinterpreted. To clarify, in my view the efficiency is dB/W and the dB/V is the sensitivity (aka Voltage sensitivity).
And as well as Le varying with frequency, it also varies with position of the voice coil, not much for "better" drivers.
Klippel measurements of the SI HT18 at Xmax show the Le going from around 1.9mH coil in to over 4mH coil out.
Anyway, here are a positive example for the claim. Exactly the same motors but different cones sizes:
https://faitalpro.com/en/products/LF_Loudspeakers/product_details/index.php?id=201050130
https://faitalpro.com/en/products/LF_Loudspeakers/product_details/index.php?id=201060135
https://faitalpro.com/en/products/LF_Loudspeakers/product_details/index.php?id=201070135