Curt Campbell's Halcyon build thread

Okay,

new measurements and pictures.

I have taken the set-up in our solarium, no walls just vynil. So no bass reinforcement or reflexions.

The bass is louder at 80 and 200 Hz inside.
315 Hz and 630 Hz are softer inside.
5 kHz and higher seems to be vynil reinforcement !!! No problems I hear nothing.
From 50 Hz to 160 Hz, the bass is 10 dB louder. (200 Hz inside)

I am tempted to try different wirewound resistors to rise the Alpair by 5 dB.

Freq - living room - solarium
20 54- 56
25 59 60
31 68 65
40 71 71
50 76 78
63 78 79
80 83 78
100 78 80
125 81 82
160 80 80
200 79 70
250 71 72
315 66 69
400 70 72
500 67 68
630 66 69
800 69 68
1k 70 base 70 base
1,25 73 71
1,6 73 73
2,0 73 74
2,5 72 74
3,15 70 72
4 70 72
5 68 75
6,3 67 73
8 70 78
10 62 68
12,5 64- 64
16 60- 60
20 k 60- 58

20240901_164524.jpg
20240901_164547.jpg
20240901_165910.jpg
 
Not the best plot as Apple Numbers is a bit limited. Got a >10dB peak/trough. I think something is broken. Not sure adjusting a resistor will fix. The way it is troughing makes me think the Alpairs are out of polarity from the SBs but I'd expect the Alpair response to pop up more as frequency goes up. However, series crossovers are a bit foreign to me. Also, the Alpairs may not be rising in frequency as much if the meter is off-axis.

I recommend the following:
1. Describe the test setup. Is this one speaker playing or both? Is the SPL meter on-axis with the Alpair? If not, how high are you placing the meter?
2. Verify all installed parts match the schematic. The pictures posted, can't determine values.
3. Sketch the schematic as implemented on the board and verify against Curt's schematic.
3. Retake and repost pictures so the crossover board is captured in its entirety in one shot with parts and wire leads labeled.
4. Test and label the wiring. Ensure there is continuity and they have correct polarity.
5. Check each driver is working (hook each one up on its own to an amp and play a test signal).

Also, did you get around to restuffing and tuning the bass section?


Screenshot 2024-09-07 at 16.19.39.png
 
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I have replaced R2021(8,2 Ohms) by a Solen wirewound 7,5 Ohms resistor. All frequencies vent up !!! low +3DB, mid +3 dB and high +3 dB ! So it is not much help.

Next I will check the SBA drivers polarity, double check that is as I already have checked once.
 
The R2021 is for the level adjustment over all, and the R2022 4.7 is paralleled with the 8.2 above the Fc of the 10uF cap for reduced padding in the upper register. If you like where the mids are, then leave the 8.2 alone. While I would not recommend shorting R2022 for the final fix, you could to see if this is the direction you need to go. I would possibly recommend paralleling a 3.3 or 4.7 resistor with the R2022 to lift it a bit more than Curt had it. It might be such that Curt's preferred polite top end is not what you prefer.
 
wolf_teeth,

but Curt suggested reducing R2021 ???? (see post no. 394). R2021 does seem to influence over all loudness. My measurements show that. I find 10 dB on average for the lows over the mids to be a lot. Maybe 5 dB would be fine for me.
 
wolf_teeth,

see also post 390, Curt states that R2021 adjusts the Alpair level.

You suggest to put a wire insted of R2022 to confirm it will rise the Alpair right ? Eventually putting two 4,7Ohms resistors in parallel instead of one right ?

thanks,

Walter
 
I have re-checked polarity, it is good. I have checked the schematic of the cross-over, as far as I understand it is identical.

wolf_teeth seems to have a point as changing the 8,2 resistor for a 7,5 one raised the volume of all frequencies.

Walter
 

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I recommend the following:
1. Describe the test setup. Is this one speaker playing or both? Is the SPL meter on-axis with the Alpair? If not, how high are you placing the meter?
both speakers playing, SPL in the middle at Alpair level,
2. Verify all installed parts match the schematic. The pictures posted, can't determine values.
done
3. Sketch the schematic as implemented on the board and verify against Curt's schematic.
done
3. Retake and repost pictures so the crossover board is captured in its entirety in one shot with parts and wire leads labeled.
done
4. Test and label the wiring. Ensure there is continuity and they have correct polarity.
done
5. Check each driver is working (hook each one up on its own to an amp and play a test signal).
Ouf! lots of work, this is a plan B for now. I am soldering directly in the living room. Waiting for wolf_teeth confirmation.

Walter
 
R2021 adjusts Alpair level related to the woofers above wherever the low xover point is. The R2022 adjusts for the rolloff of the topend to balance it out above the 10uF cap. If you use these close to a wall, you may want less resistance there.

Yes. You have stated my intention if you want more topend. You'll have to play with the resistance of R2022 as the smaller it gets, the higher the top octave output becomes. What I suggested by paralleling another 4.7 gives you 3-4dB more in the upper treble.
 
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4. Test and label the wiring. Ensure there is continuity and they have correct polarity.
done
5. Check each driver is working (hook each one up on its own to an amp and play a test signal).
Ouf! lots of work, this is a plan B for now. I am soldering directly in the living room. Waiting for wolf_teeth confirmation.

Walter
#4 - how did you check polarity on the Alpair? I had to put a AA battery across it's terminals to determine which was + as there was no distinguishing marks on the solder tabs. Not sure if the ones you have are different.

#5. If you hear music when sticking an ear up to each driver then good to go. No need to desolder.

At this point, with what wolf_teeth posted, I suggest using some same value resistors for R2021 and R2022 and some gator clip leads to see what combination gets you closer to proper balance.
 
We have good results here !!!

I have paired R2022 with another 4,7Ohms resistor. The graph shows the results.
I consider one dB as within the margin of error.
The dotted line is the original design.
The bass is the same. Only 200 Hz is 2 dB lower.
315, 400 and 500 Hz have higher output. 400 Hz being quite high.
1,25kHz, 1,6 and 2 kHz went down. It is flatter now but I wonder if a slight bump in this area is desirable or not.
Subjectively the sound is quite diffrent: bass seems right, not too loud but present. This is nice.
Mid and treble seem to have raised output and there is some bite to the sound. This is nice too.

Over time I will see if the pleasure stands. I wonder if an in between setup, let's say an additional 6.2 Ohms resistor insted of the 4,7 Ohm I just installed, would raise less the low mids and lower less the 1,25kHz to 2kHz region. And I guess the bass would sound a little louder.

Thanks for your help, comments welcome,

I have to go on vacations as of saturday.

Walter
 

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Metric version of Halycon. Adjusted for availability of some material e.g. MDF here is 18mm and the waveguide tube for the Mid-range has external dia. of 220mm. Hence is a little wider and the baffle is 36mm thick. Cut sheet list also attached. This gets cut and built in January - so will find out if there are any bad calculations at that time - but look good after much checking. Will post photos as it progresses.
 

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