Oh! Mr. Dave design of reverse polarity of tweeter seem work best. I will use your crossover design for my speakers. I am so gratitude to Mr. Dave's afford for helping other people whom lack of knowledge and experience. I am agree with Mr.Turbowatch 2 ( I have to listen more. I apologized for some of my manner, I will improve myself)
back to crossover, I want to know why reverse polarity of tweeter seem better than??? I never think about reverse polarity before because original NAC-61 has no Polarity reverse in tweeter.
back to crossover, I want to know why reverse polarity of tweeter seem better than??? I never think about reverse polarity before because original NAC-61 has no Polarity reverse in tweeter.
Troels doesn't post reverse null images for his LR crossovers. A personal choice I suppose.
The reason the tweeter polarity is reversed is:
a) you have a flat baffle
b) I have used a steeper slope on the SBNAC to damp the breakup and to get phase alignment with a flat baffle.
Now - 2 caveats with my crossover:
1. I have based this on simulation and not measurements. there's always a chance I've got something wrong
2. There is no off axis data to show you how the speaker will behave in the room / power response. that is - it may look good on-axis but may have more peaks and dips due to the slopes chosen as you move off axis. Without measurements, there is no certainty here
The reason the tweeter polarity is reversed is:
a) you have a flat baffle
b) I have used a steeper slope on the SBNAC to damp the breakup and to get phase alignment with a flat baffle.
Now - 2 caveats with my crossover:
1. I have based this on simulation and not measurements. there's always a chance I've got something wrong
2. There is no off axis data to show you how the speaker will behave in the room / power response. that is - it may look good on-axis but may have more peaks and dips due to the slopes chosen as you move off axis. Without measurements, there is no certainty here
Thank you very much all members and especially Mr. Dave for your help.
I would buy a couple of extra resistors so you can pad the tweeter down some more. Say 1 ohm and 2 ohm. Also make all resistors 10w. The resistor in the woofer circuit I haven't modelled for power handling but shouldn't need more than 10w. You could double up to be sure if you can't buy a 20w resistor. That is 2 * 1ohm in parallel
My 45Amp is only 2 watt and normal i listen soft not loud. Is 10 watt resistor at woofer not suffice?
The last crossover I posted had a 2 ohm tweeter resistor. This provides a "flat" on axis response, but you may find the tweeter too hot in your room. By using 3 ohms, then 4 ohms, here is how it pads down the tweeter
Light blue line = 2 ohm tweeter resistor
Medium blue = 3 ohm resistor
Dark blue = 4 ohm resistor
These changes do not require any other crossover changes.
Light blue line = 2 ohm tweeter resistor
Medium blue = 3 ohm resistor
Dark blue = 4 ohm resistor
These changes do not require any other crossover changes.
The SB17NBAC may have a peak as shown ~ 760Hz. I say may, as this is all simulated data, no off-axis measurements, so whether this peak is real or not I can't guarantee.
However, if you find vocals a bit "shouty" on the speaker. it could be this peak. I have added a notch filter highlighted below. you can see how it flattens the region. It does require quite a large inductor (4.7mH)
Impedance is not impacted (i.e. minimum is still 4.5 Ohms ~ 2700Hz
However, if you find vocals a bit "shouty" on the speaker. it could be this peak. I have added a notch filter highlighted below. you can see how it flattens the region. It does require quite a large inductor (4.7mH)
Impedance is not impacted (i.e. minimum is still 4.5 Ohms ~ 2700Hz
I found this measurement I took of the SB17NBAC35-4 (I have 2 waiting to go into a project). Although this gate is extremely short, there is no 760Hz hump. Unfortunately I can't recall the baffle size and measurement conditions. In otherwords, I don't think that notch filter will be needed:
Then notch filter is omit. I keep your original crossover schematic. If there is any adjustment and it is not much bother you. Please tell me about your revised crossover to prevent 760Hz peak. Thank you in advance.
I am so gratitude for you help so much. I think in case of 760hz peak can not correct by crossover. Maybe I use EQ in Jriver Media player software to adjust about 2db around that problem. However if crossover can be redesign to cope with it, I will be so glad to adjust.
I forgot you were using JRiver and if you do sense a peak, then EQ will be a good solution. I don't think it will be a problem though. so the crossover in post #37 still stands
https://www.diyaudio.com/community/...6adc000-4-frd-zma-sharing.403170/post-7450247
https://www.diyaudio.com/community/...6adc000-4-frd-zma-sharing.403170/post-7450247
The last crossover I posted had a 2 ohm tweeter resistor. This provides a "flat" on axis response, but you may find the tweeter too hot in your room. By using 3 ohms, then 4 ohms, here is how it pads down the tweeter
Light blue line = 2 ohm tweeter resistor
Medium blue = 3 ohm resistor
Dark blue = 4 ohm resistor
These changes do not require any other crossover changes.
Thank you so much mr. dave. I will add 1R resistor next to 2R resister to pad down the tweeter.
Light blue line = 2 ohm tweeter resistor
Medium blue = 3 ohm resistor
Dark blue = 4 ohm resistor
These changes do not require any other crossover changes.
Thank you so much mr. dave. I will add 1R resistor next to 2R resister to pad down the tweeter.
I missed this. If you only have a 2 watt amplifier, then 10w single resistors will be fine. Don't expect these speakers to play loud though with only 2w (i.e. these are 86dB with 1w/1m therefore 89dB peak at 1m with 2w).My 45Amp is only 2 watt and normal i listen soft not loud. Is 10 watt resistor at woofer not suffice?
I can't play loud in my bedroom. It will bother neighbor even i close windows and turn on air condition. The fine is expensive if he sue. I usually play around 60-72db max distance 2 meters. However i have 2nd amp 6n2 4p1l push pull around 8 watts.
Here are my files for the SB17
https://www.diyaudio.com/community/...ith-da25bg08-06-project-in-leak-boxes.358217/
Thread #8 I think.
https://www.diyaudio.com/community/...ith-da25bg08-06-project-in-leak-boxes.358217/
Thread #8 I think.
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