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Multi-Way Conventional loudspeakers with crossovers

Crazy crossover possible?
Crazy crossover possible?
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Old 15th February 2020, 01:01 AM   #41
ntell411 is offline ntell411
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open baffle 33" W x 55" H where I gain 6db boost from floor reflection for woofers and IF they could be run parallel as 4 ohm load then another 3db boost in sensitivity. The DCR of the coil is 1.48 ohms which would add resistance to the pair and keep them above 4 ohms which is preferred; this is why I didn't think the full ranger was going to cause problems with overpowering the bass units and it's true sensitivity is not 100db but closer to 95 according to others who have measure them.
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Old 15th February 2020, 01:03 AM   #42
ntell411 is offline ntell411
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Speaker L-Pad Attenuator 100W Mono 1" Shaft 8 Ohm They use a potentiometer so are variable.
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Old 15th February 2020, 01:05 AM   #43
Galu is offline Galu  Scotland
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Quote:
Originally Posted by ntell411 View Post
true sensitivity is not 100db but closer to 95 according to others who have measure them.
My posts have been based on the sensitivity information you first supplied, so the goalposts have now changed in your favour!
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Old 15th February 2020, 01:19 AM   #44
Galu is offline Galu  Scotland
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Quote:
Originally Posted by ntell411 View Post
IF they could be run parallel as 4 ohm load
In that case, why not reconsider my post #2.
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Old 15th February 2020, 01:19 AM   #45
ntell411 is offline ntell411
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Great, a small victory! Both you and AllenB have been very helpful but this is not easy for me to understand. My goal was to use 2 woofers for increased bass, increased sensitivity with one Full ranger in an open baffle configuration with the least amount of crossover components possible-preferable just an inductor. I was also going to either suspend in free air or make a pyramid shaped top to the speaker baffle so that there would be minimal area around the full ranger thus significantly reducing its low frequency output and not cause interference with the 2 woofers. I still think it can work if I ran 2 woofers in parallel with the inductor (8+8)/2=4 ohms + 1.48 ohms (coil)= 5.48 ohms while the full ranger is still an 8 ohm load and less sensitive??? It may be time for a glass of Hennesy at this point while I mull over all of the great suggestions you guys have made!
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Old 15th February 2020, 01:25 AM   #46
ntell411 is offline ntell411
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absolutely. thanks!
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Old 15th February 2020, 01:27 AM   #47
Galu is offline Galu  Scotland
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The DC resistance of the coil is already included in the impedance figure, it does not add to it.

I still think my post #2 is the solution. The component values would be easy to calculate for the inductor in series with the 4 ohm woofer combination and the capacitor in series with the 8 ohm full range. This is the correct way to produce the desired amplifier load.

P.S. Just saw your last reply!
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Old 15th February 2020, 01:28 AM   #48
AllenB is offline AllenB  Australia
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Crazy crossover possible?
Quote:
Originally Posted by Galu View Post
I wonder what power rating the L-pad resistors would have to be to safely match the higher sensitivity full range with the woofers?
I once ran 100dB mids/highs HP@300Hz on about 0.5W, so knocking that down 6dB and wanting to reach the same levels would have taken 2W all up.
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Old 15th February 2020, 02:25 AM   #49
jjasniew is offline jjasniew  United States
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@ntell411 - Generally, going with separate amplifiers makes the option of doing crossover at the line level - versus the speaker level - a distinct possibility. Certainly more inconvenient than being able to just use one amp, but offers greater flexibility.

Also, if you do that, you can enter the world of DSP processing. This allows you to create your "crossover" in software using an app and immediately see how you like its sound. I've done this using a miniDSP (V1...) and while I dont like its overall sound for listening pleasure, it still allows me to quickly and easily try different responses - the equivalent of circuit topologies in R's, C's and L's - in a small fraction of the time it would take to buy components and build.

For example, my "initial guess" was 250Hz. I quickly found out I dont want to cross there - by listening. Then I tried 70 - OK. Let's see if I can nudge it a bit higher, try 100. Good. You can do this almost as fast as I can type these words - a no brainer decision from my perspective.

Once you get a sound you like (or have measured as Good) dialed in, then you can attempt to replicate it in an all-analog hardware design. As a DSP line level crossover abstracts what it's doing in a language we all universally understand, I'm sure many here would be able to show how to do exactly that. Line or at speaker level.
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Last edited by jjasniew; 15th February 2020 at 02:33 AM.
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Old 16th February 2020, 07:29 PM   #50
ntell411 is offline ntell411
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Just to clarify: When I look at the impedance graph of the Goldwood woofer, it dips below 6 ohms at certain frequencies from 40-250hz so that if I use two of them in parallel (<6+<6)/2=<3 leading to<3 ohm load to amplifier. The inductor I want to use (low pass at 250hz) has a DCR of 1.48 ohms. Would that raise the overall impedance of the woofers above 3 ohms and make it a safer load for the amplifier as I prefer one amplifier for the entire system.
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