I have a strange thing to share with you guys about the behavior of this speaker using a crossover with a screw terminal block that has steel components vs no terminal block (all Wago spring clip connectors).
The red trace is the speaker with the steel terminal block. It has a bass peak at 125Hz and sudden falloff at 100Hz. Green is the second speaker with the same crossover but no terminal block.
So I put the second XO on the first speaker (thinking the behavior was something strange about the woofer). But it ended up measuring nice and smooth like the green trace. So I redid the XO1 to eliminate steel terminal block and both speakers measure basically identically now. What is the reason that the steel terminal block wreaks such havoc on the frequency response? I would never have imagined the effect to be so significant.
The both match now, plus the bass behavior is smooth and the falloff is shallow.
The red trace is the speaker with the steel terminal block. It has a bass peak at 125Hz and sudden falloff at 100Hz. Green is the second speaker with the same crossover but no terminal block.
So I put the second XO on the first speaker (thinking the behavior was something strange about the woofer). But it ended up measuring nice and smooth like the green trace. So I redid the XO1 to eliminate steel terminal block and both speakers measure basically identically now. What is the reason that the steel terminal block wreaks such havoc on the frequency response? I would never have imagined the effect to be so significant.
The both match now, plus the bass behavior is smooth and the falloff is shallow.
It is worth seeing if the measurements agree after windowing out room reflections in case there was something that went unnoticed between measurements. It's hard to explain the differences just from the impedance curve. That said, I actually recently posted this:
https://www.diyaudio.com/community/...ion-measurement-challenge.407527/post-7577824
It doesn't seem likely that steel would cause this specific effect, but with all the weirdness I've observed with steel hardware I prefer to avoid it.
https://www.diyaudio.com/community/...ion-measurement-challenge.407527/post-7577824
It doesn't seem likely that steel would cause this specific effect, but with all the weirdness I've observed with steel hardware I prefer to avoid it.
It’s not room effects as the measurements were made at same spot and same mic location by simple swap of XO or speaker. The absence of room effects to the changes can be seen that they have the same response below 600Hz where that effect is greatest. The only other thing was I had maybe 6in of hand twisted wire from the steel terminal block to the XO parts just to keep the wires together. Could this coiling be interacting with the magnetic fields from the inductors? It’s
Kind of related, I've observed inductance of inductors change when I mount them on a PCB with a ground plane.
Yes, that’s a well known effect so we leave bare FRP board region beneath the inductor. This applies more to air coil vs iron core which are dominated by the core geometry.
Air coils radiate a lot of magnetic field and really communicate with each other more than you think, which is why they always need to be perpendicular to each other in orthogonal x y z orientation.
Demo of air coil crosstalk being enough to power another unconnected speaker.
Air coils radiate a lot of magnetic field and really communicate with each other more than you think, which is why they always need to be perpendicular to each other in orthogonal x y z orientation.
Demo of air coil crosstalk being enough to power another unconnected speaker.
One other thing to note is that within the first 3 sweeps to get a frequency response, the harmonic distortion can vary wildly. Sometimes going low, then high, but generally trending to high for first 10 sweeps. It’s not until deep bass excursion break in that it starts to go down again.
I know that break in happens from my own experience, but how intense the effect is depends of the way the driver is build. Soft suspension HIFI chassis show usually near to no effect at all, while tough PA driver may drop up to 10Hz in Fs. It is very interesting to see this in such well done measurements. Thank you!
I think it is a good idea to play some intense music, like heavy metal, on a brand new speaker, loud and for a few hours, before judging them. Anyway if, maybe 4 or 5 hours don't improve anything, I seriously doubt 100 hours more will make the speaker pleasant.
The problem I see is the opaque border to the Voodoo kind of "break in", that plagues many audiophile circles.
The real, physical break in does not have anything to do with the 100-2000 hour break in period many dealer and even some manufacturer talk about. In many markets people have a limited period of time, like two weeks, during which they can return anything bought online. So blaming the unsatisfying sound of a sold speaker on insufficient "break in" is a convenient way of getting over this period.
The customer may even hear some subjective improvement over time, because ones hearing adapts to non linear speaker response. Also, people start to select recordings that sound "good" and call those, a specific speaker may not be able to reproduce well, to be "bad recordings".
I think it is a good idea to play some intense music, like heavy metal, on a brand new speaker, loud and for a few hours, before judging them. Anyway if, maybe 4 or 5 hours don't improve anything, I seriously doubt 100 hours more will make the speaker pleasant.
The problem I see is the opaque border to the Voodoo kind of "break in", that plagues many audiophile circles.
The real, physical break in does not have anything to do with the 100-2000 hour break in period many dealer and even some manufacturer talk about. In many markets people have a limited period of time, like two weeks, during which they can return anything bought online. So blaming the unsatisfying sound of a sold speaker on insufficient "break in" is a convenient way of getting over this period.
The customer may even hear some subjective improvement over time, because ones hearing adapts to non linear speaker response. Also, people start to select recordings that sound "good" and call those, a specific speaker may not be able to reproduce well, to be "bad recordings".
I agree that a few hours is generally all that’s needed. But it should be several mm of cone motion and bass notes if possible.
I just cue up some pink noise with REW. Low-pass filter at 25Hz, turn it up until you've got the desired excursion, and leave the cones to wobble for a while.
Chris
Chris
My personal belief is that the spring terminal connectors are superior to screw terminals in almost all cases. The issue with screw connections is that the copper is quite ductile, and it will continue to deform after the screws have been tightened. This causes the terminal to loosen over time. The Wago and other spring connectors will maintain a constant pressure even if the wire compresses. I always go back and re-tighten screw terminals to make it less likely to fail. I am also using lever or other spring based connectors in all my work projects. They are both quicker to install and appear more reliable, or at least with my unscientific evaluations.
That is one reason I use copper alligator clips for almost everything. They rarely disappoint me.
Alligator clips are good for prototyping and testing, but the compression force is many times greater in the spring lever connectors. You have to pull really hard to separate them. I tug on the lever connectors to test them with way more force than an alligator clip would tolerate. IMO, the only thing better than the levers is a good solder joint.
The Wago’s are UL rated for 600v and 20A. Conductor material is copper and accepts up to 12ga wires. I find them super secure and do not seem to add any strange signal to my crossover circuits.
https://www.wago.com/us/wire-splicing-connectors/compact-splicing-connector/p/221-413
With a bag of Wago’s and a kit of major LRC values, I can prototype any crossover in 15 minutes typically.
After a week or so listening to a Wago-plank crossover, I’ll convert to P2P soldered connections with zip ties and stick that inside the cabinet. If it goes forther than that, I’ll have a PCB and custom components (L and C) made.
Here is what one of my typical development crossovers looks like in the Wago-plank version:
Then move to P2P soldered version:
Here is the production PCB version:
https://www.wago.com/us/wire-splicing-connectors/compact-splicing-connector/p/221-413
With a bag of Wago’s and a kit of major LRC values, I can prototype any crossover in 15 minutes typically.
After a week or so listening to a Wago-plank crossover, I’ll convert to P2P soldered connections with zip ties and stick that inside the cabinet. If it goes forther than that, I’ll have a PCB and custom components (L and C) made.
Here is what one of my typical development crossovers looks like in the Wago-plank version:
Then move to P2P soldered version:
Here is the production PCB version:
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Are the clear plastic bobbin coils in the production version the custom made ones you order from somewhere or are they available off the shelf from someone? curious who.
I have one of those component-Wago rat's nests sitting on my dining room table atm, haha, careful that from iron core doesn't scratch the finish -eek!
All the inductors on the production PCB are custom made. Even the capacitors are custom wound to the exact value (I am not limited by the usual values).
Here is the crossover that I designed for the Galion Audio transmission line speaker. Notice the custom labeling on the capacitors. The iron core inductor is also custom wound.
I finished the soldered P2P plank XO for the NX6A and AMT2-4 speaker. It’s all buttoned up and playing music now.
Here is the crossover that I designed for the Galion Audio transmission line speaker. Notice the custom labeling on the capacitors. The iron core inductor is also custom wound.
I finished the soldered P2P plank XO for the NX6A and AMT2-4 speaker. It’s all buttoned up and playing music now.
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Even minuscule changes ro the positions or stuff in the room can make a difference. Just apply some gating to get rid of the echoes and then check the harmonics of the anechoic data.
It was well controlled A/B test with only change being the XO assembly method. Nothing touched on the lab between the two measurements. So not a room boundary effect and note that it shows effects up at 450Hz, 750Hz and 1.5kHz. Well above regions of room boundary effects.
Btw, speakers all buttoned up and playing lovely music now. The soldered P2P measures identically to the Wago P2P.
Btw, speakers all buttoned up and playing lovely music now. The soldered P2P measures identically to the Wago P2P.
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Here are the measurements of the final soldered (red, blue) XO vs Wago (green) vs Steel terminal block XO (Grey - which had 7ohms padding vs final at 8.5ohms):
We can see that the steel is the anomalous one.
Here is just comparing final soldered XO Ch1 and Ch2 for clarity - look at the matching:
Here are the measured harmonic distortion plot sweeps for soldered XO Ch1 and Ch2, note that Ch2 the driver appears to have more inherent distortion near 100Hz, here is Ch2:
And here is Ch1:
We can see that the steel is the anomalous one.
Here is just comparing final soldered XO Ch1 and Ch2 for clarity - look at the matching:
Here are the measured harmonic distortion plot sweeps for soldered XO Ch1 and Ch2, note that Ch2 the driver appears to have more inherent distortion near 100Hz, here is Ch2:
And here is Ch1: