The DQ10 and LXmini have something in common. Both have drivers dampened on their backside with felt. In the case of the DQ10 a driver has a sheet of felt covering the entire rear of a driver. The LXmini has a detached tube filled with stuffing behind a driver. Can someone explain the purpose of these two techniques, how they differ in effect and what change, if any, each has on Qts and Fs of the respective drivers?
Thanks
Thanks
If you look at Linkwitzlab.com you will see this explanation,
"With a 700 Hz LR2 crossover to a small, full-range and open-baffle driver, and with a diffusing as well as attenuating structure for controlling the rear radiation, the polar response tends towards cardioid behavior and reduces reflections from objects behind the speaker.
With directivity controlled in this way the LXmini becomes much less sensitive to room placement, while also gaining in 3D imaging precision."
I imagine the DQ10 designer was similarly looking to fine tune the rear radiation, but this is only speculation.
"With a 700 Hz LR2 crossover to a small, full-range and open-baffle driver, and with a diffusing as well as attenuating structure for controlling the rear radiation, the polar response tends towards cardioid behavior and reduces reflections from objects behind the speaker.
With directivity controlled in this way the LXmini becomes much less sensitive to room placement, while also gaining in 3D imaging precision."
I imagine the DQ10 designer was similarly looking to fine tune the rear radiation, but this is only speculation.
Thanks,
Yea, I already read that. But back in the dark recesses of my mind I vaguely recall that covering the back of a driver with felt will affect Qts and Fs. But I don't recall how. Anybody know what happens?
I don't see how the LXmini method will do that. But both methods should act as filters of a sort.
I have checked but cannot find a pic or spec of the back of the Seas Prestige FU10RB H1600-04. Is the voice coil vented through the magnet?
If not, there seems no need for the stuffed tube behind it. An appropriately dense, thick felt pad should do just fine. The tube might be there primarily to hold the driver in place and the filling helps control rear dispersion to a very limited degree.
Yea, I already read that. But back in the dark recesses of my mind I vaguely recall that covering the back of a driver with felt will affect Qts and Fs. But I don't recall how. Anybody know what happens?
I don't see how the LXmini method will do that. But both methods should act as filters of a sort.
I have checked but cannot find a pic or spec of the back of the Seas Prestige FU10RB H1600-04. Is the voice coil vented through the magnet?
If not, there seems no need for the stuffed tube behind it. An appropriately dense, thick felt pad should do just fine. The tube might be there primarily to hold the driver in place and the filling helps control rear dispersion to a very limited degree.
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Since the LXmini full range driver has a substantial gap between the basket and the structure behind it (only the magnet is inside the pipe) I would be surprised if driver parameters like Qts and Fs would be shifted substantially. As you observe the thing about a driver is you have to mount it somehow...if there is no baffle then you are pretty much stuck with mounting via the magnet structure. So you want to mount it, capture some of the back radiation and absorb it, make it visually coherent with the pipe supporting the low frequency driver and make it easy to build.
Engineering is often about taking many requirements and solving them with the simplest collection of bits.
Engineering is often about taking many requirements and solving them with the simplest collection of bits.
As complete speakers systems they are on different planets.
But, in both systems there is one driver operated as a dipole with a fibrous material behind it. That is the similarity I was trying to understand.
I was thinking of doing up a LXmini clone using the DQ10 style felt backing. But the drop in efficiency is significant so I will go LXmini style.
Thank you kevin and waslo. You gave me what I needed.
But, in both systems there is one driver operated as a dipole with a fibrous material behind it. That is the similarity I was trying to understand.
I was thinking of doing up a LXmini clone using the DQ10 style felt backing. But the drop in efficiency is significant so I will go LXmini style.
Thank you kevin and waslo. You gave me what I needed.
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