I currently have a pair of DIY speakers using the DA175 & DC28F with a textbook 8Ωx8Ω 2500hz LR2, Textbook Zobel & Textbook Fixed L-Pad.
They sound really good but there are definitely crossover issues to be worked out.
So.....I got ahold of a copy of XOver 3-Pro and started simming up crossovers.
I have spent countless hours trying to match the DA175 to the DC28F in flat response good phase tracking and decent impedance curves.
I have finally settled on an approximate 1600hz LR2 w/ zobel on the woofer and BW3 on the tweeter with fixed L-Pad.
Here is the data that I have come up with for the BW3 in comparison to the current Textbook crossover in place.
I have noticed that the Tritrix MTM has this tweeter LR4 @1450hz and I am wondering if my BW3 will be adequate.
They sound really good but there are definitely crossover issues to be worked out.
So.....I got ahold of a copy of XOver 3-Pro and started simming up crossovers.
I have spent countless hours trying to match the DA175 to the DC28F in flat response good phase tracking and decent impedance curves.
I have finally settled on an approximate 1600hz LR2 w/ zobel on the woofer and BW3 on the tweeter with fixed L-Pad.
Here is the data that I have come up with for the BW3 in comparison to the current Textbook crossover in place.
I have noticed that the Tritrix MTM has this tweeter LR4 @1450hz and I am wondering if my BW3 will be adequate.
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1600Hz crossover sounds very low. Not clear what you mean by Zobel on woofer either. Metal woofer would need some hard rolloff to avoid sounding harsh and metallic. Schematic helps. 🙂
Why reinvent the wheel? What was wrong with the Karma Indignia design?
No notch filiters, but looks OK to me.
Why reinvent the wheel? What was wrong with the Karma Indignia design?
No notch filiters, but looks OK to me.
Textbook can be far from reality. Read this : crossovers
These projects use true LR2 acoustic slopes :
The Seas ER18DXT ported two way
QUATTRO
Note you must offset the tweeter to achieve LR2 : stepped baffle (Stepped Baffle Study) or horn/waveguide tweeter, a workaround with a network delay line
Illuminator-Monitor
etc.
These projects use true LR2 acoustic slopes :
The Seas ER18DXT ported two way
QUATTRO
Note you must offset the tweeter to achieve LR2 : stepped baffle (Stepped Baffle Study) or horn/waveguide tweeter, a workaround with a network delay line
Illuminator-Monitor
etc.
There is also the 'Silver Al Ultimate Edition (UE)'. The AL's do a lot of things right.
My own thoughts- Keep the DC28 above 1.7kHz if possible, and 2kHz is really a golden-zone for it.
Later,
Wolf
My own thoughts- Keep the DC28 above 1.7kHz if possible, and 2kHz is really a golden-zone for it.
Later,
Wolf
Einric, anyone who talks about LR2 and LR4 has been hanging round Zaph Audio too much. The fact is GOOD circuits design themselves depending on the drivers. 😀
I have combined the best of the two designs into a conventional flat baffle speaker. I leave the box details to you.
I have combined the notched cone-breakup suppression of the Silver AL UE design with the kinder impedance and suppression of Fs tweeter resonance of the other Indignia design. The 3.5R series and 12R shunt resistors replace the single 7R resistor of the Karma Indignia for reasons Wolf will understand. This is a good thing IMO, but nothing stopping you trying a single 7R series resistor on the tweeter and no shunt 12R. I have added 1R to the woofer notch at 6.8kHz because high Q filters and overly deep notches are a bad thing in general. You may adjust tweeter level by varying the 3.5R resistor to taste. A very nice speaker, I reckon. 😎
I have combined the best of the two designs into a conventional flat baffle speaker. I leave the box details to you.
I have combined the notched cone-breakup suppression of the Silver AL UE design with the kinder impedance and suppression of Fs tweeter resonance of the other Indignia design. The 3.5R series and 12R shunt resistors replace the single 7R resistor of the Karma Indignia for reasons Wolf will understand. This is a good thing IMO, but nothing stopping you trying a single 7R series resistor on the tweeter and no shunt 12R. I have added 1R to the woofer notch at 6.8kHz because high Q filters and overly deep notches are a bad thing in general. You may adjust tweeter level by varying the 3.5R resistor to taste. A very nice speaker, I reckon. 😎
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Hi,
No good reason to use such a low DCR coil in the notch
position though then. Use a cheaper higher DCR coil.
rgds, sreten.
No good reason to use such a low DCR coil in the notch
position though then. Use a cheaper higher DCR coil.
rgds, sreten.
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That surprises me, because I thought everything about it was messed up. 😀
Polarity is wrong for a start, so it must image badly. Impedance dips very low too.
Is it meant to be time-aligned? Couldn't get that to work either. 😕
Below is the suggested schematic for the Silver ALS UE. After that is my sim effort with tweeter polarity corrected and the expected better phase alignment of a second order tweeter. The L-pad is plain wrong too IMO. I did much better with different values. 😎
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The two pictures I posted earlier are of the simulated crossover I was looking at building and the speakers I have already built.
The box is about .9cuft gross with a 34hz tuning.
My baffle width is 9" and height is 21-5/8".
I don't want to build a new box since the bass in this design is great for all my listening levels.
@ System7.....Is the scratch design you posted designed for the drivers in question?
They weren't labeled as such, just wondering.
I do like your simulation it gets the tweeter into a more comfortable range for my liking.
Must the 1.5mh be .60Ω? I have grown to like the P-Core inductors and at 1.5mh it has a dcr of only .16Ω.
I know this will effect the woofer response but will it be detrimental to the design or just give me more bottom end?
My simulated crossover does dip down to 1.5Ω in my simulations and that was the last thing I was trying to work out.
The box is about .9cuft gross with a 34hz tuning.
My baffle width is 9" and height is 21-5/8".
I don't want to build a new box since the bass in this design is great for all my listening levels.
@ System7.....Is the scratch design you posted designed for the drivers in question?
They weren't labeled as such, just wondering.
I do like your simulation it gets the tweeter into a more comfortable range for my liking.
Must the 1.5mh be .60Ω? I have grown to like the P-Core inductors and at 1.5mh it has a dcr of only .16Ω.
I know this will effect the woofer response but will it be detrimental to the design or just give me more bottom end?
My simulated crossover does dip down to 1.5Ω in my simulations and that was the last thing I was trying to work out.
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Shawn used measured plots to get there, so it was done correctly. How can you say it is bad if you've not heard it or measured it yourself?
Build it as-is.
Later,
Wolf
The redesign I did was based on the assumption that the original two designs were about right in the major respects. I really only raised the tweeter crossover a little from the indignia design to match the better Silver ALS bass filter. It was amazing that the Visaton drivers were so close in spec to the ones you bought. I see no reason to change your fairly standard box.
Inductor DC values will make very little difference going from 0.6R to 0.1R. Can you hear 0.3dB? 😀
@wolf_teeth, if you can't see that Silver ALS schematic is wired out of phase just by looking at it, or that the impedance goes unpleasantly low, you shouldn't be building speakers. Your blinkered defense disappoints me here, because you do some very good innovative stuff that I always read with interest. As with MarkK's ER18DXT speaker and the Sonus Faber Extrema designs, I clearly stated what was wrong with them and what was right with them. The science will win.
I didn't model it, alright- it's not my design. Typically, 12dB electrical filters will be wired out of phase- you should know that. Granted the Silkie extends lower than some other tweeters, so it has enough lowend to not automatically be 4th order acoustic rolloff.
If you want me to model it, I will, but let's look at a few things first-
Why are you getting a low impedance dip?
The reactance of the LC notch in combination with the 1st order LP coil will not allow a very low impedance dip because the increase of impedance with frequency keeps it above a certain point. Alone with the driver maybe, but with the LP coil- it should be fine.
The tweeter has a 12 in parallel, which yields a nominal sensitivity of 4.8 ohms, and then adds a 10 ohm resistor to that. Theoretically, the tweeter should be above 12 ohms for it's passband, which is also not an issue. Even in the plot you posted, the impedance dips to 4 ohms, which is also not an issue for most amplifiers.
Where did you get your plots? are they measured or spec-sheet? That can make a huge difference.
Again- it's not my design, nor have I modeled it; but it should be fine. I know Shawn and know he would not do something that ill in a xover design.
I'm only defending the design of a friend and the premise and how it sounded. I know for a fact the top-end was not rolled off.
In terms of the ER18/DXT from MarkK, I just think you don't understand the results he got. There is more to that design than you think, because Mark also knows what he is doing.
Believe me or not- suit yourself, but I know what I've heard, and I definitely trust those 2 designers. Thank you for your compliment on my behalf.
Later,
Wolf
wolfie, you are missing why the Silver ALS is bolloxed, much as I admire your blind defense of a friend at some level. The padded tweeter impedance of, say 14.8 ohms is simply underdamping the tweeter filter. It's almost like the tweeter is blown the crossover is resonating. That is why the impedance dips so low. Sort of thing that blows amplifiers fuses at best, or fries output transistors at worst. 🙂
The Silver ALS and MarkK's designs both have goodish notched woofer filters, But the rest is a mess in both cases. In MarkK's case, his tweeter notch is at 1.6kHz...far from the required 900Hz Fs of the SEAS DXT tweeter.
Don't waste time defending the indefensible. You are too talented. 😎
The Silver ALS and MarkK's designs both have goodish notched woofer filters, But the rest is a mess in both cases. In MarkK's case, his tweeter notch is at 1.6kHz...far from the required 900Hz Fs of the SEAS DXT tweeter.
Don't waste time defending the indefensible. You are too talented. 😎
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Hi,
There is only one person round here talking bollox about stuff they don't understand.
rgds, sreten.
There is only one person round here talking bollox about stuff they don't understand.
rgds, sreten.
Care to explain why I am wrong, sreten? I await your answer with great interest. This is, after all, a free forum. 🙂
Hi,
The requirements are not what you imply, and its not wrong.
The requirements are clearly stated, and then complied with.
Its clear to some why the notch is at 1.6KHz.
rgds, sreten.
Okaaaaayy......How does this apply to the DA175 w/ DC28F?
I'm not opposed to exotic crossover designs but there comes a point of diminishing returns on complexity.
Sooooo....I'm looking between the Silver AL "UE" and System7's design.
Both of which use a 12Ω resistor that parts express doesn't carry.
This leaves me with Madisound or Meniscus.
Is the 12Ω a critical value for some reason? Or will 12.5Ω be sufficient?
I'm not opposed to exotic crossover designs but there comes a point of diminishing returns on complexity.
Sooooo....I'm looking between the Silver AL "UE" and System7's design.
Both of which use a 12Ω resistor that parts express doesn't carry.
This leaves me with Madisound or Meniscus.
Is the 12Ω a critical value for some reason? Or will 12.5Ω be sufficient?
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