"Mechano22" - a small 2-way speakers with linear on-axis and power response characteristics

[ernperkins]

There's also a very comprehensive Mechano thread over at audiosciencereview. They've created crossover pcbs, etc.

https://www.audiosciencereview.com/...ers-h-v-off-axis-measurements-included.41757/

 

[XMechanik]

Another episode from the "Mechano" series: a small 3-way design (7l) with drivers arranged for use "lying on side". Codename Mechano325.

The drivers:
DSA135-8 link
PC83-4 link
ND28F-6 link

Filter schematics and and charts:


THD -47dB or 0.5% (at 86dB)


Assembled crossover (3 filters):


Box dimensions: 290x174x263mm.
Only the tweeter is flush-mounted.


Midrange driver chamber


Total components cost was about 280EUR/pair (enclosures not included)

 

[motokok]

This could make the other budget 3-way thread redundant! Any chance of attaching all the xmachina project files?

 

[wolf_teeth]

Very similar to my Purveyor build. I used the same midrange. Nicely done, I like it!

 

[drummerdrewski]

@XMechanik What a fantastic little build! Thank you so much for your work in this world. Is this a sealed or vented design? I'm surprised to see an F6 of 40hz out of such a small driver.

 

[XMechanik]

Is this a sealed or vented design? I'm surprised to see an F6 of 40hz out of such a small driver.

It's a vented design with a slotted port on the back.

As for the low f6, this woofer has been optimized for application in small enclosures. Slightly reduced sensitivity also improves the final result in this aspect.

 

[drummerdrewski]

Wonderful, thank you. What was your tuning frequency of the vent in the enclosure to hit 40hz F6? @XMechanik

 

[XMechanik]

Here's NF chart of my tuning: c.a. 45Hz as I'm reading it. f6 is also an effect of 100Hz area correction in the crossover and adjusting the level of the rest of the characteristic to the level in this region.

 

[Jdodd16]

Can anyone help me with purchasing the crossover components in the US?
A bit new to the DIY speaker scene. I literally for the life of me cannot find this air coil anywhere online:

Jantzen Audio core coil 0.68mH / cylindrical / 0.162ohm / dr.1mm Fe 0.021kg / dia.20, length 40mm.

I searched for these exact specs on soundimports.eu as well and was able to find:

Jantzen Audio 000-0113 | 0,68 mH | 0,155 Ω | 3% | 13 AWG | Air Core Coil

Wondering if this is the correct one? But the impedance doesn't match exactly. Any help is greatly appreciated! Am looking to put together a pair of the mechano22's using a 3d printed housing (Have to modify @celstark's design on ASR: https://audiosciencereview.com/foru...axis-measurements-included.41757/post-2247946 for the dayton drivers)

 

[AllenB]

Normally you would use any appropriate 0m68H coil. Either one that has been made with crossover use in mind, or anything which has similar properties.

The use of an iron core is optional, but it helps to reduce resistance (which is of interest for matching to the original design). Some cores might not be appropriate for higher frequency use.

As for the resistance, the 0.162 vs 0.155 ohm is close enough. You might get away with a bigger difference, but at some point you'd want to view those differences in the simulator to decide whether their effect would be noticeable.

 

[Jdodd16]

Thanks Allen. Looks like I’ll download and learn that program to play with his crossovers with parts I can buy. Much appreciated.

 

[Jdodd16]

I have put together a list of components for these speakers in the US, comes to about 230$ - This seems restrictively expensive for a budget speaker, so will have to shelf this idea for now.

Speaker Crossover Parts List​

Inductors​

Component	Quantity	Unit Price	Total Price
3.7 mH Steel Laminate Inductor 18 AWG	2	$14.20	$28.40
Solen 0.82 mH Perfect Lay Inductors 14 AWG	2	$27.30	$54.60
Solen 0.68 mH Perfect Lay Inductors 14 AWG	2	$24.60	$49.20
Madisound 0.12 mH 19 AWG Air Core Inductor	2	$5.40	$10.80

Capacitors​

Component	Quantity	Unit Price	Total Price
Solen 11uF 400V Polypropylene Capacitor (Part #027-571)	2	$10.30	$20.60
Solen 9.1uF 400V Polypropylene Capacitor (Part #027-566)	2	$7.78	$15.56
Dayton Audio DMPC-8.2 8.2uF 250V Polypropylene Capacitor (Part #027-426)	2	$4.08	$9.16
Dayton Audio DMPC-4.3 4.3uF 250V Polypropylene Capacitor (Part #027-419)	2	$2.15	$4.30
Dayton Audio DMPC-3.3 3.3uF 250V Polypropylene Capacitor (Part #027-420)	2	$1.19	$2.38
Solen 0.47 mfd Fast Cap 630V PPE Series	2	$4.40	$8.80

Resistors​

Component	Quantity	Unit Price	Total Price
Jantzen Audio 0.18 Ohm 10 Watt Audio-Grade Superes Resistor (Part #255-937)	2	$6.75	$13.50
Dayton Audio DPR10-4.7 4.7 Ohm 10 Watt Precision 1% Audio Grade Resistor (Part #006-4.7)	2	$2.15	$4.30
Dayton Audio DPR10-2.4 2.4 Ohm 10 Watt Precision 1% Audio Grade Resistor (Part #006-2.4)	2	$2.15	$4.30
Madisound 12 Ohm, 25 Watt Wirewound Resistor	2	$1.20	$2.40
Madisound 10 Ohm, 25 Watt Wirewound Resistor	2	$1.20	$2.40

 

[mayhem13]

This is where you loose me…..$230 worth of XO components for $115 worth of drivers

 

[markbakk]

For the 3,7mH that one is ok. Wrt the other inductors: find those that set you back around $10/pair. Capacitors can be found cheaper elsewhere too I'd say, apart from professional distributors. And just use cheap low inductance wirewound resistors. People claiming that they can hear the difference sure will have a hard time proving such statements.

To help out a bit: 0,68mH-ish is just fine, like 0,82mH-ish.

 

[A4eaudio]

I have put together a list of components for these speakers in the US, comes to about 230$ - This seems restrictively expensive for a budget speaker, so will have to shelf this idea for now.

​

Check out https://www.jfcomponents.com/

Very good quality stuff for good prices.