Please review my 3-way crossover

Hmmm, are you really after a structural bass boost by 6dB? As most of us here would not and Allen has designed a crossover essentially measuring flat (that is how it's meant from the recording). Apart from that, the room gain will add bass enough, depending on the setup up til about 9dB, apart from room modes.

The adding of drivers works thus: at relatively low frequencies (wavelength bigger than 3 times the diameter of the drivers) double woofers close to each other will produce double the sound pressure level at listening distance. By switching them in series, you'll bring the sound pressure of each woofer back to half the original level. So essentially, the series switching leads to +/- 0dB SPL, but at double the impedance (and half the current from the amp).

If you switch them in parallel however, you end up with +6dB SPL. You will need efficiency figures for your mid and tweeter that are in that new ballpark to successfully establish a speaker that is well-balanced. But hey, if you really want that bass-heavy (ear-tiring) set, no one here will stop you ;)

You are right, Allen made a great crossover and I am very grateful for that.
Thank you for your ideas and explanations. Definitely I won´t use paralel connection. I will think about series or just one woofer. Thank you very much.
 
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Hmmm, are you really after a structural bass boost by 6dB? As most of us here would not and Allen has designed a crossover essentially measuring flat (that is how it's meant from the recording). Apart from that, the room gain will add bass enough,
At the start daimler said "baffle step loss". This means he was reading an article that isn't thinking about the room. This is why we have always called it "baffle step compensation" instead. (daimler, just curious, where did you learn "loss"?)

I did apply just under 6dB BSC to the responses before I set the filters. The room will give some of that back, and take some more away with cancellations. It will be frequency dependent. Room placement is maybe the first thing to consider here. It is not a perfect solution but it becomes an important consideration.

So some aim for less that 6dB. Even though it is frequency dependent, if you can get the response smooth then you may take an average. Maybe this crossover will benefit from some adjustment when it is in its position because it is location dependent.
 
Allen, you are right. Loss was ment in free space not in room. I didn´t understand it well.
Thank you for explanation and once again thank you very much for awesome crossover, your patience and your help. I appreciate it very much and I am very grateful. I also want to thank all members who helped me and explained a lot of things to me.
 
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Vituixcad has a target slope tool. It is difficult to learn but it is useful.
 

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I have one more question.
It seems that two woofers in paralel increase SPL by 6 dB while is series lower the SPL by 6 dB. Is that correct?
Correct for parallel, incorrect for series.
Compared to one woofer:
Two parallel: double Sd area (+3db), half impedance (+3db) = +6db
Two series: double Sd area (+3db), double impedance (-3db) = 0db

Two in series have the same spl output as one woofer,
only advantage with series is lower distortion compared to one,
because each series woofer works at half voltage/excursion.
 
You might think again about the acoustic summing of two coherent sources that are close together wrt to the wavelength. And double the impedance = half the voltage across one woofer. Hint: half the voltage = -6dB. It's also important to discern sound power from sound pressure level.
 
Correct for parallel, incorrect for series.
Compared to one woofer:
Two parallel: double Sd area (+3db), half impedance (+3db) = +6db
Two series: double Sd area (+3db), double impedance (-3db) = 0db

Two in series have the same spl output as one woofer,
only advantage with series is lower distortion compared to one,
because each series woofer works at half voltage/excursion.

Thank you Danny.
By the way the speakers you made looks fantastic. Very interesting reading.
 
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So should I definitely use only one woofer?
No, that's not what I meant. This was about how acoustic summing works.

Regarding your design: For most domestic applications a 12", a 5" and a tweeter will do very well and the relative simple setup saves you the expense, the trouble and the design issues of bigger systems.

When you start with 2 x quite normal 12" woofers, midrange and tweeter power handling becomes an issue. Just because one obviously wants to play loud (otherwise there's no need for 2x12), thermal and max excursion limits of the drivers have to be considered in the design of the crossover (I won't start about power compression issues). This all if and only if the units are up to their task in the first place.

Bottom line: if you opt for 2x12, consider either 2 midranges or a bigger (7") midrange, those will give you more acoustic power per Watt and therefore less issues coupling them with two woofers. But this all will give you more trouble coupling to the tweeter in turn. And since you won't go for 2 tweeters, solutions with horns/waveguides come to mind. Hope I don't talk you out of your dream, but 3-way design isn't simple, let alone 3-way design with certain SPL requirements.
 
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Just to be funny, the solution to 2 tweeters is to use one and raise the crossover frequency. Now you need a four way.

The answer is to know what a driver can and should be capable of. How and where to use it. You don't normally wake up and think OK, today I will make a three-way speaker.
 
I do not need extreme power handling, I will listen in room about 25 m2 so I understand that 2 woofers are useless but I like that design. I understand what you mean and I am very grateful for explanation. Especially midrange will not be capable to handle so much power as 2 woofers could do but if I do not need more than 80-90 dB in distance of 4 m away of the speakers it should be OK, right? With theese 4 ohm speakers maybe about 2x20 W should be enough to have 90 dB in 4 m. Is that correct? Speakers will have sensitivity about 86 dB (based on crossover).
I was thinking about this 7" midrange
Dayton Audio - RS180-4 7" Reference Woofer 4 Ohm
but as Allen said, it may be useless especially with my power needs.
 
Few days ago I have finished my 3 way project so I want to thank all members who helped me with their advice.
Especially I want to thank to AllenB.
Allen, you helped me a lot and your crossover design is awesome. It works fantastic. Sound is crystal clear, mids and highs are briliant,
bass is strong, deep and tight and the sound is just perfect. This is exactly what I wanted to achieve.
I am enjoying hours of listening hi-res music every day and the sound is improving and after about 10 hours of playing it is much better than in the beginning.
Allen, once again, THANK YOU VERY MUCH for your kindness and help. You helped me make one of my dream come true so I am very grateful.
THANK YOU
 
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