Small 2-way speakers with linear on-axis and power response characteristics (Scan Speak and SB Acoustics drivers). H&V off-axis measurements included

[Bugless]

Can the port be 3d printed? Maybe out of abs or asa?

I printed the ports for my pair out of TPU. I got the idea after I noticed that my KEF LS 50 ports are a flexible material. Turned out great!

 

[Mr.Christiee]

In terms of audible results, MDF will be every bit as good as plywood, assuming you don't cheap out on the MDF.

But please be warned: MDF is nasty stuff. The fine, toxic dust gets everywhere if you aren't set up to control it aggressively. When I do cut it, I wear a serious respirator the whole time and also run a giant ceiling-suspended dust collecting filter for 8+ hours in my shop. The dust still gets everywhere. I've been moving more and more to baltic birch plywood.

My build of these is using plywood, for what it is worth.

Did you round the edges or bevel them in towards the tweeter waveguide?

 

[Raxumit]

Did you round the edges or bevel them in towards the tweeter waveguide?

I am still building them, midway through crossovers now. I'm reasonably confident I got everything right, but I decided to get a Dayton DATS unit to do impedance testing for a change, so I'm waiting for that to arrive.

I am thinking of putting a small roundover on the baffles, but I haven't made up my mind yet.

 

[tllw]

Thank you for sharing your design with us!

I am wondering if it is going to be trivial to swap the woofer with the one you are using in Mechano 24 - 12W/4524G00?

 

[XMechanik]

I suspect the result would be quite random and not worth the effort and cost. Using a different woofer would require redesigning the crossover.

 

[Mr.Christiee]

@XMechanik

I am looking to build a stellar little pair of bookshelf speakers. Something I'd be happy holding on to for life. Typically used in a small-medium sized room with a sealed sub. These definitely look like they fit the bill. I want to thank you for your time, energy, and efforts in designing/creating these.


QUESTIONS:

A) Mechano23 is best at what listening distance? Do they have a wide 'sweet spot' ?

B) Can the Mechano23 be sealed with foam port bungs for tricky placements? How much would that change the frequency response? Just low-end?

C) What frequency would you high-pass these at? (both in ported and also in sealed configuration)

D) Is it okay to chamfer the front edges of the baffle around the tweeter?

E) Any other 'premium' tweaks, upgrades, or modifications you would suggest/recommend?

Many thanks!

 

[yogurt21]

B) Can the Mechano23 be sealed with foam port bungs for tricky placements? How much would that change the frequency response? Just low-end?

I think it would make more sense to simply make them with a passive radiator instead of the port in this specific case. See this for discussion of this variant.

But this is a basic summary of different things you could do, as I've modeled for my own purposes:
- original design (green, bold) gives you the best -6dB extension
- passive radiator (yellow; shown without added weight) adds more upper bass sacrificing the -6dB extension a little bit; with added weight it behaves more like the original version
- fully sealed design (blue) just looses a lot of output below 150Hz
- then a higher port frequency variant (green; also has abt. 1l extra volume) boosts upper and middle bass output, but at a cost of a higher -6dB; but this makes sense mostly for using them without a subwoofer which I gather you plan to use

 

[Maiky76]

The simulations are good indications.

Discussion about the port limitations:

Small 2-way speakers with linear on-axis and power response characteristics (Scan Speak and SB Acoustics drivers). H&V off-axis measurements included

Such a nice design! I'm also from northern Europe and hope to get into DIY speakers. Do you have any advice about retailers for parts? Most chatter I see online order from partsexpress in the US. :/

www.audiosciencereview.com

Alternative with multiple ports:

Small 2-way speakers with linear on-axis and power response characteristics (Scan Speak and SB Acoustics drivers). H&V off-axis measurements included

Assembling and electronic work I am well acquainted with. However, I am new to from-scratch speaker builds. I do not have the facility or accommodations to do woodworking currently. Where would be the best place to get the panels cut? I've cut a bunch of speakers completely myself, but baffles...

www.audiosciencereview.com

make sure to read the follow up comments

Small 2-way speakers with linear on-axis and power response characteristics (Scan Speak and SB Acoustics drivers). H&V off-axis measurements included

Assembling and electronic work I am well acquainted with. However, I am new to from-scratch speaker builds. I do not have the facility or accommodations to do woodworking currently. Where would be the best place to get the panels cut? I've cut a bunch of speakers completely myself, but baffles...

www.audiosciencereview.com

A way to improve power handling under particular circumstances :

Small 2-way speakers with linear on-axis and power response characteristics (Scan Speak and SB Acoustics drivers). H&V off-axis measurements included

Trying to clarify some issues with google drive that flagged zip file with the software. Since this happened 8 months ago and I have no idea how to make any progress, it may never get resolved I'm afraid. If you're looking for other options, Github allows hosting .exe files without any issues...

www.audiosciencereview.com

A digression

If one wants to maximize power handling and SPL let’s say for a 2.1 or Home Theater configuration then
Box: 4.6L net (with actual resistor of the filter that would need to be changed)
FB~83.5Hz 2xMBR35 (14.5cm, 19.2cm2) or 1xMBR35 (cut down to 6.4cm after starting from a longer value ;-), 9.6cm2)
NOT optional Active 2nd order High-pass filter set to 95Hz with a Q of 0.62 (Home Theater amplifier?) can be simulated with WinISD (SOS HP filter)
This will provide close to optimal power handing / max SPL with no port issue. All the LF (below 80Hz) duties would then be fulfilled by one or multiple SWs.
96dB (above 120Hz) would barely exceed 1mm excursion on the LF driver, well within its capabilities.
In fact, the system becomes thermally limited i.e. the driver will burn before bottoming/breaking with about 101dB for 40W.
One would need to be careful not to damage the speaker because there will be no warning up until the driver is burnt.

 

[jaakkopetteri]

then a higher port frequency variant (green; also has abt. 1l extra volume) boosts upper and middle bass output, but at a cost of a higher -6dB; but this makes sense mostly for using them without a subwoofer which I gather you plan to use

While this alternative is great in terms of headroom, I would think it might have some "unnecessary" group delay. I think sealed would be nice for most if there's any DSP available to boost things up a bit around 100Hz

 

[yogurt21]

While this alternative is great in terms of headroom, I would think it might have some "unnecessary" group delay. I think sealed would be nice for most if there's any DSP available to boost things up a bit around 100Hz

Indeed it does:

13ms @ 60Hz should still be acceptable though.

 

[Maiky76]

A more precise comparison would be
1. to add the EQ if needed (sealed) and the High Pass filters required for coupling with a SW for all three systems.
2. compare the SPL when the Xmax is reached, not the Max SPL provided by Winsid which will be different if no Dynamic rage compressors (DRCs) are used.

That can be simulated by
1. increasing the signal until Xmax is reached at the upper hump (higher frequency one) in the driver excursion for PR and BR systems.
Sealed systems should have a nearly constant excursion.
2 add High Pass filter to have the same excursion at the lower hump and the upper hump in the driver excursion for PR and BR systems
3. readjust the signal to ensure Xmax is reached both at the lower and upper hump in the driver excursion
At that point, if no DRC are used, one has reached the Max SPL of the system or a good approximation of it.

Note that some drivers are thermally limited i.e. one can't reach Xmax before exceeding the driver the power dissipation limit.
Most are mechanically limited, Xmax is reached at a much lower power that it can handle. Some make funny noises even without bottoming and will limit the power handling.
That is where DRC are useful, one can limit the excursion of the system at LF while increase the SPL where it can handle more power.

 

[cfwotzka]

Just finished my pair and I'm simply amazed how good this speakers sound "out of the box".
Excellent job XMechanik, many congrats and many thanks for sharing!
My crossover ist external and currently only provisional made from the parts I had at hand. This speaker is worth to use selected good components for the crossover and
I will order accordingly.

 

[Maiky76]

A more precise comparison would be
1. to add the EQ if needed (sealed) and the High Pass filters required for coupling with a SW for all three systems.
2. compare the SPL when the Xmax is reached, not the Max SPL provided by Winsid which will be different if no Dynamic rage compressors (DRCs) are used.

That can be simulated by
1. increasing the signal until Xmax is reached at the upper hump (higher frequency one) in the driver excursion for PR and BR systems.
Sealed systems should have a nearly constant excursion.
2 add High Pass filter to have the same excursion at the lower hump and the upper hump in the driver excursion for PR and BR systems
3. readjust the signal to ensure Xmax is reached both at the lower and upper hump in the driver excursion
At that point, if no DRC are used, one has reached the Max SPL of the system or a good approximation of it.

Note that some drivers are thermally limited i.e. one can't reach Xmax before exceeding the driver the power dissipation limit.
Most are mechanically limited, Xmax is reached at a much lower power that it can handle. Some make funny noises even without bottoming and will limit the power handling.
That is where DRC are useful, one can limit the excursion of the system at LF while increase the SPL where it can handle more power.

Here are the results from WinISD:
No series resistor

Blue -> sealed for similar output above 50Hz
Red -> BR 8L 45Hz: stock tuning
Black -> BR 8L 53Hz: my take on BR tuning
Pink -> PR 8L 0g: SBA Oval PR with 0g added
Green -> BR Assisted: my advice for active system with a SW for frequencies below 80Hz (LF source not localizable)



Xmax as described in the previous post
Green -> BR Assisted: my advice for active thermally limited i.e. the signal is reaching the maximal power of the driver and therefore we maximize the SPL in the useful band when coupled with a SW above 80Hz.
The driver is well within its mechanical limits and the THD will be at worst similar to that of the BR/PR above 200Hz and better in the 80 - 200Hz range system in this usage case.

Transfer Function

Filter Transfer Function:
I have omitted the High Pass on the Sealed system as the Xmax is not reached at LF

SPL @ Xmax
Sealed system much lower SPL as usual.

Group Delay

IMO the sealed system would only make sense for a three way version of the speaker with integrated (sub) woofer crossed over above or at 200Hz.

 

[Clang2213]

In terms of audible results, MDF will be every bit as good as plywood, assuming you don't cheap out on the MDF.

But please be warned: MDF is nasty stuff. The fine, toxic dust gets everywhere if you aren't set up to control it aggressively. When I do cut it, I wear a serious respirator the whole time and also run a giant ceiling-suspended dust collecting filter for 8+ hours in my shop. The dust still gets everywhere. I've been moving more and more to baltic birch plywood.

My build of these is using plywood, for what it is worth.

Thank you for the answer! I will be careful with the MDF.

Since this is my first crossover build I'm a bit confused by the different parts used in the review sample and the picture of the crossover from XMechanic. For instance the 1.5mH coil from Solen from the review is off by 0.03 ohm and is an air core instead of an iron core, the 18uF capacitor is a Metallized Polyester capacitor in the review while it is a electrolytic capacitor in the picture from XMechanic, and the resistors in the review are 10w instead of 5w. My question is if any of this matters? Can I pick and choose components specifed by the review and XMechanic at random depending on what is easily available to me, or should I stick with a configuration that 100% matches either of them?

 

[Raxumit]

Thank you for the answer! I will be careful with the MDF.

Since this is my first crossover build I'm a bit confused by the different parts used in the review sample and the picture of the crossover from XMechanic. For instance the 1.5mH coil from Solen from the review is off by 0.03 ohm and is an air core instead of an iron core, the 18uF capacitor is a Metallized Polyester capacitor in the review while it is a electrolytic capacitor in the picture from XMechanic, and the resistors in the review are 10w instead of 5w. My question is if any of this matters? Can I pick and choose components specifed by the review and XMechanic at random depending on what is easily available to me, or should I stick with a configuration that 100% matches either of them?

I just grabbed all the parts suggested by Amir in his writeup. I haven't seen anyone flag his parts picks as problematic, so I'm pretty sure I'm fine.

I will say what little I know/have heard:

• Air cores are considered to be superior to iron core for speaker crossovers, but can be fine depending on the circumstance. There are iron cores in my ZDT 3.5's, for example, to save money when the designer thought it inaudible/worth the tradeoff. Here's an elaborate discussion.
• Electrolytics are cheaper up front but can die in the long term (15+ years I think). I've used electrolytics in the past, but always feel better when I don't. I have ended up using some of my speakers for 10+ years, so the modest extra cost makes sense for the potential lifetime of the speaker in my particular case.
• Small variances in resistance are not material as I understand it.
• I believe the 10W vs 5W is about power handling in the resistors. More power handling capacity is not going to hurt, so long as you have the right value.

Experts should interject here if I'm not right about anything.

The only problem I've had with the parts choices in Amir's review so far is they are bigger than those in XMechanic's crossover layout, and led to me shoving things around on the board. It's not terrible though.

 

[Clang2213]

I just grabbed all the parts suggested by Amir in his writeup. I haven't seen anyone flag his parts picks as problematic, so I'm pretty sure I'm fine.

I will say what little I know/have heard:

• Air cores are considered to be superior to iron core for speaker crossovers, but can be fine depending on the circumstance. There are iron cores in my ZDT 3.5's, for example, to save money when the designer thought it inaudible/worth the tradeoff. Here's an elaborate discussion.
• Electrolytics are cheaper up front but can die in the long term (15+ years I think). I've used electrolytics in the past, but always feel better when I don't. I have ended up using some of my speakers for 10+ years, so the modest extra cost makes sense for the potential lifetime of the speaker in my particular case.
• Small variances in resistance are not material as I understand it.
• I believe the 10W vs 5W is about power handling in the resistors. More power handling capacity is not going to hurt, so long as you have the right value.

Experts should interject here if I'm not right about anything.

The only problem I've had with the parts choices in Amir's review so far is they are bigger than those in XMechanic's crossover layout, and led to me shoving things around on the board. It's not terrible though.

Thank you again for the quick reply!

I see, that makes sense. My problem right now is that I'm based in Europe and therefore it is not economically viable for me to use Solen parts. I have been trying to find the exact parts used by XMechanic on soundimports but some are out of stock, like the 1.5mH iron core, with no restock date and some do not exist in the exact same variation at all. But if I have understood you correctly, I should be able to replace only those non available components with components from other brands with the same values as XMechanic's or Amir's components?

 

[XMechanik]

Thank you again for the quick reply!

I see, that makes sense. My problem right now is that I'm based in Europe and therefore it is not economically viable for me to use Solen parts. I have been trying to find the exact parts used by XMechanic on soundimports but some are out of stock, like the 1.5mH iron core, with no restock date and some do not exist in the exact same variation at all. But if I have understood you correctly, I should be able to replace only those non available components with components from other brands with the same values as XMechanic's or Amir's components?

You can use any components with the same or similar values. If their dimensions are different from those that I have used, the component arrangement on the pad and wiring diagram may need some adaptation.
If you're unsure if the value of the component you have is "close enough" you still can edit the component in the VituixCad to match it to your value and see the impact on the characteristics.

 

[Rick Sykora]

I just grabbed all the parts suggested by Amir in his writeup. I haven't seen anyone flag his parts picks as problematic, so I'm pretty sure I'm fine.

I will say what little I know/have heard:

• Air cores are considered to be superior to iron core for speaker crossovers, but can be fine depending on the circumstance. There are iron cores in my ZDT 3.5's, for example, to save money when the designer thought it inaudible/worth the tradeoff. Here's an elaborate discussion.
• Electrolytics are cheaper up front but can die in the long term (15+ years I think). I've used electrolytics in the past, but always feel better when I don't. I have ended up using some of my speakers for 10+ years, so the modest extra cost makes sense for the potential lifetime of the speaker in my particular case.
• Small variances in resistance are not material as I understand it.
• I believe the 10W vs 5W is about power handling in the resistors. More power handling capacity is not going to hurt, so long as you have the right value.

Experts should interject here if I'm not right about anything.

The only problem I've had with the parts choices in Amir's review so far is they are bigger than those in XMechanic's crossover layout, and led to me shoving things around on the board. It's not terrible though.
View attachment 377706

As is more of a board for mounting the components (rather than a circuit board), I find it simpler to keep the wiring on the top side of the board. Fewer holes are required and allows much easier confirmation that the wiring is done correctly.

 

[a4eaudio]

• Air cores are considered to be superior to iron core for speaker crossovers, but can be fine depending on the circumstance. There are iron cores in my ZDT 3.5's, for example, to save money when the designer thought it inaudible/worth the tradeoff. Here's an elaborate discussio

Regarding air vs iron core... Yes, sometimes cost is the deciding factor FOR THE DESIGNER. But once he has made that decision it's best for a builder to use the same kind of inductor IF POSSIBLE. The difference in DCR can affect the level of output and tonal balance. Sometimes it will be audible, but it's still a small difference so using one with different DCR isn't going to run the build.

 

[yogurt21]

Regarding air vs iron core... Yes, sometimes cost is the deciding factor FOR THE DESIGNER. But once he has made that decision it's best for a builder to use the same kind of inductor IF POSSIBLE. The difference in DCR can affect the level of output and tonal balance. Sometimes it will be audible, but it's still a small difference so using one with different DCR isn't going to run the build.

I think identical DCR air coils are available; if not, one can always go lower and compensate with a resistor.
My question is, just how impactful can the distortion of a single coil, not even wired in series with the driver, be?
I doubt it's very much.
It seems to me like the application of solid core here was quite judicious.