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

[Bicep]

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. :/

 

[somebodyelse]

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. :/

https://www.soundimports.eu among others - I don't think anything would be too hard to find.

 

[D!sco]

Congratulations on the review. Your hard work certainly paid off.

 

[dcibel]

Well done! It's surprising how well of a PIR you've got with just a basic sharp cornered rectangular baffle.

 

[Maiky76]

@XMechanik, as I said in the EQ post that's a great effort with only off-the-shelf components and simple woodwork,
I noticed that in your simulation the LF is not drooping as much as in the NFS data. Not sure why.
Maybe near field measurement inaccuracy?

The simulation of the 8L + tuning to 45Hz seems to match the NFS data characteristic
If I may, after doing a bit of simulation for the box tuning I would suggest tuning the cabinet to 51 - 53Hz instead.

That would result in a flatter response (up to +2dB above 50Hz) and most probably remove the need for EQ IMO (outside of room integration obviously).
The LF will be attenuated slightly but the power handling higher above 50Hz (about +3dB) so more usable in the useful bandwidth of the speaker.
All in all for a smaller speaker it might be a better compromise especially if listened louder.

 

[Inertiaman]

@XMechanik, as I said in the EQ post that's a great effort with only off-the-shelf components and simple woodwork,
I noticed that in your simulation the LF is not drooping as much as in the NFS data. Not sure why.
Maybe near field measurement inaccuracy?

The simulation of the 8L + tuning to 45Hz seems to match the NFS data characteristic
If I may, after doing a bit of simulation for the box tuning I would suggest tuning the cabinet to 51 - 53Hz instead.

That would result in a flatter response (up to +2dB above 50Hz) and most probably remove the need for EQ IMO (outside of room integration obviously).
The LF will be attenuated slightly but the power handling higher above 50Hz (about +3dB) so more usable in the useful bandwidth of the speaker.
All in all for a smaller speaker it might be a better compromise especially if listened louder.

Any chance you've computed the port dimensions for such tuning?

 

[D!sco]

It’s an off the shelf port so you just bandsaw a few mm off and call it good usually.

 

[J49]

Incredible. Nice work @XMechanik and thank you again for sharing this design.

My build came in around $300-350 usd for drivers and x-over components. Outstanding performance per $.

 

[somebodyelse]

It’s an off the shelf port so you just bandsaw a few mm off and call it good usually.

It's an adjustable telescopic one, so both easier and reversible if you don't like the result.

 

[D!sco]

It's an adjustable telescopic one, so both easier and reversible if you don't like the result.

Also means you could adjust it for each room. Neat. Way better than a precision port, even.

 

[ta240]

Just when I started thinking DIY speaker designs were pretty much all overpriced, underperformers that have been propped up for years by legend and myth about how amazing they are, this comes along.

 

[DualTriode]

Port resonance and high distortion as per Amir’s review. And powered. Good deal. But I bet this sounds better.

Hey it is a 5 inch woofer. Sure turn it up to 96dB it will distort.

Show me a reflex port and I will show you resonance.

Good job @XMechanik .

Thanks DT

 

[Ulf]

This really makes me want to get into DIY! @XMechanik, I realise I am asking for free stuff here, but if you made a youtube video showing off the speaker you would get a lot of views

 

[Maiky76]

The surface of the port is too small relative to the active surface of the driver (about 11%).
Even at moderate SPL the air velocity in the port exceeds 5% of the speed of sound (343m/s) which is one of the criteria to dimension a port.
The port will be non linear very quickly (as the SPL increases) and restrict the output of the system at LF.
I am not sure what level is used for the NFS but it might already be the case during Amirm'smeasurements.

If you look at the review you'll see that the resonance just above 1k that matches the expected peak at 1100Hz and is only about 10dB down compared to the main output.
Could be better... but I understand the convenience of the solution adopted by @XMechanik

For the following sims I have included 0.77R in series with the driver because of the Xover I was lazy to do the Xover sim and check the actual value....

The sizes
45Hz -> 150mm instead of 145mm (my calculation are 3.5% different from the actual recommended port length not significant IMO)

52Hz -> 106mm, first resonance predicted at 1600Hz

The point is: DIY!
So I would recommend a port that provides better linearity (larger diameter) tuned to 51 - 53Hz instead.

 

[Gringoaudio1]

The surface of the port is too small relative to the active surface of the driver (about 11%).
Even at moderate SPL the air velocity in the port exceeds 5% of the speed of sound (343m/s) which is one of the criteria to dimension a port.
The port will be non linear very quickly (as the SPL increases) and restrict the output of the system at LF.
I am not sure what level is used for the NFS but it might already be the case during Amirm'smeasurements.

If you look at the review you'll see that the resonance just above 1k that matches the expected peak at 1100Hz and is only about 10dB down compared to the main output.
Could be better... but I understand the convenience of the solution adopted by @XMechanik

For the following sims I have included 0.77R in series with the driver because of the Xover I was lazy to do the Xover sim and check the actual value....

The sizes
45Hz -> 150mm instead of 145mm (my calculation are 3.5% different from the actual recommended port length not significant IMO)
View attachment 366821

52Hz -> 106mm, first resonance predicted at 1600Hz
View attachment 366817
The point is: DIY!
So I would recommend a port that provides better linearity (larger diameter) tuned to 51 - 53Hz instead.

I have seen the standard box and port calculators online where you enter the T/S parameters but none that create port sizes given an input tuning frequency. Can you point me in the right direction please? Thanks.

 

[Bartez2000]

@XMechanik
Can I buy it as a ready-made loudspeaker?
Thanks!

 

[Chris*42]

The surface of the port is too small relative to the active surface of the driver (about 11%).
Even at moderate SPL the air velocity in the port exceeds 5% of the speed of sound (343m/s) which is one of the criteria to dimension a port.
The port will be non linear very quickly (as the SPL increases) and restrict the output of the system at LF.
I am not sure what level is used for the NFS but it might already be the case during Amirm'smeasurements.

If you look at the review you'll see that the resonance just above 1k that matches the expected peak at 1100Hz and is only about 10dB down compared to the main output.
Could be better... but I understand the convenience of the solution adopted by @XMechanik

For the following sims I have included 0.77R in series with the driver because of the Xover I was lazy to do the Xover sim and check the actual value....

The sizes
45Hz -> 150mm instead of 145mm (my calculation are 3.5% different from the actual recommended port length not significant IMO)
View attachment 366821

52Hz -> 106mm, first resonance predicted at 1600Hz
View attachment 366817
The point is: DIY!
So I would recommend a port that provides better linearity (larger diameter) tuned to 51 - 53Hz instead.

...or use a PR and there will be no port resonance, SBAcoustics for example offers PRs with twice the Sd of the woofer - but this increases the price...

 

[Hifihedgehog]

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?

 

[silverD]

This knock-down cabinet is 0.03 ft^3 smaller. The baffle is almost the exact same, just not as deep as the OP design.

 

[mga2009]

Thanks @XMechanik very nice design!!

If using in a small HT with 3+ SW, would you recommend a sealed alignment?? Any changes on the volume or XO?

Cheers!