Wanted to get thoughts and opinions on my crossover design for a 2 way design I am working on. The woofers are 8" HiVi E8 and the tweeter is GRS RT1.R-8 ribbon. Also, does doubling the woofer require you to double the volume of the enclosure. As of now I am planning on a 100L ported design.
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The reason I added the L Pad was to lower the phase angle and raise the impedance. By removing it the impedance drops to 5.5 ohms and the phase increases to 47deg. Is this an issue?
Woofer attenuators should be avoided in good xo design. And I would try without tweeter attenuation as well.
Tweeter is 93dB and two woofers in parallel give 95dB at 2,83V, which gives you possibility to make 2dB of baffle-step correction without padding down the tweeter.
And 2-3dB of BSC is enough for average listening rooms.
Tweeter is 93dB and two woofers in parallel give 95dB at 2,83V, which gives you possibility to make 2dB of baffle-step correction without padding down the tweeter.
And 2-3dB of BSC is enough for average listening rooms.
^^ No, I don't see it as a problem, and if I did I wouldn't be fixing it in that way.
By the way, if higher impedance was your goal, why didn't you remove the 30 ohm resistor?
Additionally, you can show the ranges separately in XSim.
By the way, if higher impedance was your goal, why didn't you remove the 30 ohm resistor?
The phase angle of what part of the circuit?
Additionally, you can show the ranges separately in XSim.
This is good to know. I figured the tweeter would be too bright.
The frequency response was showing recessed mids so I tried to flatten it out a bit, but if 2-3 dB isn't too bad then I will leave it that way. The mids seemed very recessed without padding down the tweeter.
It was more to flatten out the curve, the mids were looking a little recessed. I will likely remove the pad on the woofers.
I wasn't sure of the effects of impedance phase on the amplifier and read that it doesn't affect most amps, but tried to keep it under 30 deg while keeping my frequency response flat. If this does not matter I could probably get a little more out of the drivers.
Without the pads it seems like they might be a little bright. +5 dB on the low end and +8 dB on the high end
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Don't worry about the amplifier, the impedance is OK at the moment.
Use the resistors with the tweeter.
Use the resistors with the tweeter.
I see.
Your sims dont show individual responses for drivers, but I believe recessed mids are mainly due to crossover. Woofer datasheet shows flat response 150-1500Hz.
After attenuator (R2, R4) is removed, woofer section of xo is now loaded with lower impedance, giving lower cutting point. If you aim at flat-like response, try to compensate with lower values of L1, C2, L3.
However, its possible some attenuation of tweeter is still be necessary.
indeed correct, I had to cross them somewhere between 2000-2500Hz.
Here is a little more tweaking. I guess the best practice would be to measure them in the enclosure, but this should be a good starting point.
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If planning for a 100L cab then do you a favor and try to design a 3-way. But a 3 way is really more difficult to design.
Your original plan is flawed by trying to cross a 8" bass to a ribbon tweeter. The bass can't go high enough to mate the ribbon with same dispersion, you end up in straining the tweeter or with a hole in the power response.
Ralf
Use WinISD for simulating the bass alignment.
2 x E8 will work well in 73 liter and tuned to 36 Hz
(not so impressive I think 😉 )
But fully agree with giralfino ..... crossing from a 8 inch to a ribbon is a no go.
It might work with a good 1" dome in a 8" waveguide.
Also using 2 woofers you'll need to do a it as a WTW (d'appolito) or as a 2.5 way, otherwise you have massive lobing ...
and for you Xover sim; have you taken the inductance of the woofer into account? ..... I can't find data for this ... you'll need a Z correction on at least the woofers (the rising of the impedance with higher freq)
Data sheet for the E8 https://www.swanspeakers.com/product/view?id=1176
2 x E8 will work well in 73 liter and tuned to 36 Hz
(not so impressive I think 😉 )
But fully agree with giralfino ..... crossing from a 8 inch to a ribbon is a no go.
It might work with a good 1" dome in a 8" waveguide.
Also using 2 woofers you'll need to do a it as a WTW (d'appolito) or as a 2.5 way, otherwise you have massive lobing ...
and for you Xover sim; have you taken the inductance of the woofer into account? ..... I can't find data for this ... you'll need a Z correction on at least the woofers (the rising of the impedance with higher freq)
Data sheet for the E8 https://www.swanspeakers.com/product/view?id=1176
I realized this after picking the drivers and modeling the xover though I thought I could get it to work. 100L was an approximation.
I was looking into making a waveguide for the ribbon. Though I don't see many people putting ribbons in waveguides. However, I did see a write up which makes me think this is possible.
I will look into woofer inductance.
The waveguide on the tweeter led me into exploring backloaded horn designs. I worked out alot of the math and modeled it in hornrsp. It seems like it could work.
Overall, it may not be a bad idea to consider other tweeters, though I do like a challenge.
If you can achieve the in-phase and frequency response through the crossover without woofer impedance compensation, and you are using solid state amps that can handle varying impedance, then remove the impedance compensation. In other words, I cannot see it helping you here.
R2 and C3 are not helping. If you want them to roll the woofer off they need to be on the other side.
Pay very close attention to your cabinet bracing with this design. The woofers are running well up into the critical mids in a ported design, so you'll need to dampen the rear mid wash into the cab very carefully. You'll likely need to play around with placement and type of materials used to do this.
Why have you switched off the driver responses? Switch off the system phase and turn on the driver phases.
No one has commented on:
a) the ribbon tweeter power handling
b) 8" woofer beaming
Although the HiVi woofer looks good on its 30 degree off axis response, you might find the 45/60 degree off axis responses are seriously down by 2KHz. Take this Scanspeak 8" discovery woofer:
Like your HiVi woofer, the 0 degree (black) is higher than the 30 degree (green) and this is due to breakup (which you want to avoid anyway). Notice the red curve is already 8dB or so down at 2KHz.
Now if you are crossing over at 2KHz - or worse 2,500Hz, then the off axis curves will be even lower in output and after you apply a crossover, all output will be down further still.
Most people won't crossover to an 8" or larger driver, unless they are using a compression driver, or waveguide loaded dome tweeter and probably won't go above 1.5Khz.
Since you are using a ribbon, most manufacturers tend to be optimistic about how low you can cross over their drivers, or add a bunch of caveats.
In your case a 2.5KHz crossover point for your ribbon might be the absolute minimum and may well need a 3rd or 4th order electrical crossover to provide enough protection.
I think what you will find is an even power response, where upper midrange / lower treble will be lumpy / low.
In otherwords, I'm not sure these driver combinations are optimal.
Are you planning on an WTW or TWW layout? The former will be better otherwise the centre to centre spacing will cause some serious vertical lobing issues between bottom woofer and ribbon.
For example, here is a 8" 2 way done right:
https://www.diyaudio.com/community/threads/daves-8-woofer-104mm-tweeter-speaker-build.397019/
a) the ribbon tweeter power handling
b) 8" woofer beaming
Although the HiVi woofer looks good on its 30 degree off axis response, you might find the 45/60 degree off axis responses are seriously down by 2KHz. Take this Scanspeak 8" discovery woofer:
Like your HiVi woofer, the 0 degree (black) is higher than the 30 degree (green) and this is due to breakup (which you want to avoid anyway). Notice the red curve is already 8dB or so down at 2KHz.
Now if you are crossing over at 2KHz - or worse 2,500Hz, then the off axis curves will be even lower in output and after you apply a crossover, all output will be down further still.
Most people won't crossover to an 8" or larger driver, unless they are using a compression driver, or waveguide loaded dome tweeter and probably won't go above 1.5Khz.
Since you are using a ribbon, most manufacturers tend to be optimistic about how low you can cross over their drivers, or add a bunch of caveats.
In your case a 2.5KHz crossover point for your ribbon might be the absolute minimum and may well need a 3rd or 4th order electrical crossover to provide enough protection.
I think what you will find is an even power response, where upper midrange / lower treble will be lumpy / low.
In otherwords, I'm not sure these driver combinations are optimal.
Are you planning on an WTW or TWW layout? The former will be better otherwise the centre to centre spacing will cause some serious vertical lobing issues between bottom woofer and ribbon.
For example, here is a 8" 2 way done right:
https://www.diyaudio.com/community/threads/daves-8-woofer-104mm-tweeter-speaker-build.397019/