Theoretically You could force a 25mm dome tweeter to do 15Hz but it`s obvious that this is not a good way of implementing the LR-Transform.
The LR Transform Circuit is excellent to extend low frequency response of a closed box driver combination when moderately designed.
The mechanical abilities of the drivers always determine to which limit You can push them with the LR-Transform.
If You encounter distortion with Your LR-Transform, You`d want a higher linear Xmax. or bigger cone area driver (or both, or more drivers) or to apply a more moderate target function.
You could also experiment with a HP-filter before the LR-Transform.
Not only can this limit low-frequency excursion of the driver to reasonable limits it also can prevent the LR-Transform circuit itself from possible clipping due to very high-gain conditions at low frequencies, depending of Your desired target function.
The LR Transform Circuit is excellent to extend low frequency response of a closed box driver combination when moderately designed.
The mechanical abilities of the drivers always determine to which limit You can push them with the LR-Transform.
If You encounter distortion with Your LR-Transform, You`d want a higher linear Xmax. or bigger cone area driver (or both, or more drivers) or to apply a more moderate target function.
You could also experiment with a HP-filter before the LR-Transform.
Not only can this limit low-frequency excursion of the driver to reasonable limits it also can prevent the LR-Transform circuit itself from possible clipping due to very high-gain conditions at low frequencies, depending of Your desired target function.
Hi Andrew,
it`s not exactly "built into".
The LR-transform - together - with the driver in the box result in an acoustical II-order High-Pass filter.
The LR-Transform, as the name implies, only transforms the II-order High-Pass driver (+box) parameters into new ones.
It doesn`t create an additional HP-filter.
Here ya go
Now I have to say Big Thanks to richie000boy for his help with measuring the loudspeaker T/S parameters and the other math involved. Also, I can only produce basic hand drawn PCB's, so as far as Audiophile and quality go, I'm limited in what I can achieve, with what I have to hand. The box was my cousin's and got a bit damp. The driver is a cheapy car job and the case for the electronics is a Mini ATX psu case. The amp is a Technics SU-V2, which is dead on one channel. Its running off of my PC soundcard at the mo. I have a hum I cant shift yet. I'm just pleased its running.
Mike
Now I have to say Big Thanks to richie000boy for his help with measuring the loudspeaker T/S parameters and the other math involved. Also, I can only produce basic hand drawn PCB's, so as far as Audiophile and quality go, I'm limited in what I can achieve, with what I have to hand. The box was my cousin's and got a bit damp. The driver is a cheapy car job and the case for the electronics is a Mini ATX psu case. The amp is a Technics SU-V2, which is dead on one channel. Its running off of my PC soundcard at the mo. I have a hum I cant shift yet. I'm just pleased its running.
Mike
Attachments
Closer on electronics
Hi all, here's a close up of the electronics.The op-amp you see is a TLO72. I didn't have a TLO71 to hand, so I had to hang the TLO72 off the board and use one half of it. The hum's getting anoying now. Any suggestions?
richie000boy has already said the powersupply is a bit too close to the first board,(the Input mixer/Phase switch). Maybe a new case with a different layout might help?
Cheers Mike
Hi all, here's a close up of the electronics.The op-amp you see is a TLO72. I didn't have a TLO71 to hand, so I had to hang the TLO72 off the board and use one half of it. The hum's getting anoying now. Any suggestions?
richie000boy has already said the powersupply is a bit too close to the first board,(the Input mixer/Phase switch). Maybe a new case with a different layout might help?
Cheers Mike
Attachments
Cheers Mike
If I can remember
Hi Charles, I lost a partition on my harddrive that contained all my data. I think I've gone from 58hz and I'm pushing for 30hz. It seems to reach low. I just got this horrible hum when there's no signal. Just been watching/listening to a Harry Potter film and Its good. Normaly I'd get a room full of bass which reached up to vocals, now it only makes a noise when its supposed to. In some dance music instead of bass fading away lower down, it seems to stay level!
Its just this hum!
Cheers Mike
Hi Charles, I lost a partition on my harddrive that contained all my data. I think I've gone from 58hz and I'm pushing for 30hz. It seems to reach low. I just got this horrible hum when there's no signal. Just been watching/listening to a Harry Potter film and Its good. Normaly I'd get a room full of bass which reached up to vocals, now it only makes a noise when its supposed to. In some dance music instead of bass fading away lower down, it seems to stay level!
Its just this hum!
Cheers Mike
Sorry Mike
Looks as if you posted while I was writing. And then I logged out. So I didn't get the part about the hum. It looks as if you either built a ground-loop or you are using insufficient mains filtering. Most probably the first of both.
Edit: Try to plug the LTF and the amp that is driving the sub into the same mains outlet as the rest of the system.
Regards
Charles
Looks as if you posted while I was writing. And then I logged out. So I didn't get the part about the hum. It looks as if you either built a ground-loop or you are using insufficient mains filtering. Most probably the first of both.
Edit: Try to plug the LTF and the amp that is driving the sub into the same mains outlet as the rest of the system.
Regards
Charles
Hi Charles
Hi, I've been trying wire the gnd up at various points. Seems like creating loops lessens the hum. Even connecting the chassis to the earth.My crossover is variable at 12db and fixed at 12db. Basicaly a 24db lowpass Linkwitz job. The variable section has a Linear pot wired to it, to allow me to tune it to my main speakers. The wires aren't screened. I figure if I moved it about, as its not mounted to the front panel, if it picked up anything it would change as it was handled. But nothing happens. I've added extra capacitance to the power rails, and that didn't help either.
As for ground loops, my wiring is of screened cable inputs and outputs.The tracks on the pcb's that carry the signal earths and automaticaly make up the 0volts rail for the power supply.The first board has a red, black and blue wire.Red and black carry plus minus volts and the blue connects to the gnd of the first board. Then the crossover and Linkwitz T. just use the Red and Black and don't have the blue. I've since wire extra earth wires here and there and only reduced hum by a small amount.
Everyone has said about Xmax and cone travel, well with this circuit,I'd say the cone doesn't travel that far and when I built the Circuit on Mr.Linkwitz's website(THOR), the cone didn't half move. Apparently its different to the Transform.
I can't wait to find out what it sounds like, when I've gotten rid of the hum.
Cheers Mike
(Where's richie000boy gone? Hope he's okay)
Hi, I've been trying wire the gnd up at various points. Seems like creating loops lessens the hum. Even connecting the chassis to the earth.My crossover is variable at 12db and fixed at 12db. Basicaly a 24db lowpass Linkwitz job. The variable section has a Linear pot wired to it, to allow me to tune it to my main speakers. The wires aren't screened. I figure if I moved it about, as its not mounted to the front panel, if it picked up anything it would change as it was handled. But nothing happens. I've added extra capacitance to the power rails, and that didn't help either.
As for ground loops, my wiring is of screened cable inputs and outputs.The tracks on the pcb's that carry the signal earths and automaticaly make up the 0volts rail for the power supply.The first board has a red, black and blue wire.Red and black carry plus minus volts and the blue connects to the gnd of the first board. Then the crossover and Linkwitz T. just use the Red and Black and don't have the blue. I've since wire extra earth wires here and there and only reduced hum by a small amount.
Everyone has said about Xmax and cone travel, well with this circuit,I'd say the cone doesn't travel that far and when I built the Circuit on Mr.Linkwitz's website(THOR), the cone didn't half move. Apparently its different to the Transform.
I can't wait to find out what it sounds like, when I've gotten rid of the hum.
Cheers Mike
(Where's richie000boy gone? Hope he's okay)
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