Help with 2.5/3 way
Hi friends,
After debating about a good quality 2way many people suggested going 2.5way. After research and a lot of thought what makes more sense is to keep my floorstanders, and make them sing.
The floorstanders are made by morel but the original drivers were cheap quality. I tried sb acoustics sb16pfc25 and sb29rdc and even with the morel crossover, which is way wrong since the SB16 drivers are 8 ohm and sb29rdc 4ohms (morel woofer/mid was 6ohm and Tweeter 8ohm) the sound is much better.
The mid driver is at a separate 12 liter sealed box and the bass driver is at a separate 35 liter reflex box
The front baffle measures at 20cmX94cm
The configuration is woofer-mid-tweeter
Here is where I need you guys to step in.
I can do it 2.5way. In that case should I cut holes at the wood that separates woofer and mid in order to unite the volume for both drivers?
Should I keep it 3way adjusting the crossover to the new drivers and keeping the separate volume for mid and woofer?
A friend who has experience, simulated the 2.5way as is(separate volume for each driver) and get these results. What do you think of his design?
Going 3way instead of 2.5way with 6inch midbass drivers, does it makes sense?
Hi friends,
After debating about a good quality 2way many people suggested going 2.5way. After research and a lot of thought what makes more sense is to keep my floorstanders, and make them sing.
The floorstanders are made by morel but the original drivers were cheap quality. I tried sb acoustics sb16pfc25 and sb29rdc and even with the morel crossover, which is way wrong since the SB16 drivers are 8 ohm and sb29rdc 4ohms (morel woofer/mid was 6ohm and Tweeter 8ohm) the sound is much better.
The mid driver is at a separate 12 liter sealed box and the bass driver is at a separate 35 liter reflex box
The front baffle measures at 20cmX94cm
The configuration is woofer-mid-tweeter
Here is where I need you guys to step in.
I can do it 2.5way. In that case should I cut holes at the wood that separates woofer and mid in order to unite the volume for both drivers?
Should I keep it 3way adjusting the crossover to the new drivers and keeping the separate volume for mid and woofer?
A friend who has experience, simulated the 2.5way as is(separate volume for each driver) and get these results. What do you think of his design?
Going 3way instead of 2.5way with 6inch midbass drivers, does it makes sense?
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There are some issues you need to consider with the 2.5 way design. The fact that you can double your radiating area at low frequencies is a tremendous advantage. However, the design of the low woofer's slope is a real exercise in compromise. If your woofer slope is too shallow relative to the mid-woofer, the woofer will retain significant output at the crossover frequency with the tweeter but at a different distance and phase angle from the mid-woofer. This complicates integration. Many successful 2.5 way designs I have seen use a slightly steeper slope on the lower woofer to further decrease output relative to the mid-woofer. You have a very shallow slope with the 2.7 mH inductor interacting with the driver's coil inductance.
The other issue is some downward lobing caused by the phase angle of the woofer relative to the mid-woofer. In his Nomex 164 MkII design Troels Gravesen accounts for this by tilting back the baffle, even above and beyond the tweeter offset. This is a very good design to study. He uses separate networks on each woofer.
Designing a 2.5 way can be a rewarding experience. There are however, additional issues to consider. I have found that with 2.5 ways it is essential to run your testing and simulations at various listening elevations.
The other issue is some downward lobing caused by the phase angle of the woofer relative to the mid-woofer. In his Nomex 164 MkII design Troels Gravesen accounts for this by tilting back the baffle, even above and beyond the tweeter offset. This is a very good design to study. He uses separate networks on each woofer.
Designing a 2.5 way can be a rewarding experience. There are however, additional issues to consider. I have found that with 2.5 ways it is essential to run your testing and simulations at various listening elevations.
I am not familiar with your CAD program but the one thing I notice is that you have zeros for the XYZ location of each driver. This seems to indicate the simulation assumes all three drivers are concentric radiating from the exact same point. This will not provide you very useful information. The z axis value difference between the mid and tweeter is usually critical in establishing the response around the crossover. With a 2.5 way the Y axis value relationship of the drivers also increases in importance since the two woofers have a significant overlap region.
If you can't determine the actual acoustic center of your drivers, SB provides in their website some information on relative acoustic center differences between their drivers. This should help you with the Z values. Without that I am afraid the curves are not very useful.
If you can't determine the actual acoustic center of your drivers, SB provides in their website some information on relative acoustic center differences between their drivers. This should help you with the Z values. Without that I am afraid the curves are not very useful.