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Multi-Way Conventional loudspeakers with crossovers

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Old 31st October 2012, 11:21 PM   #41
tinitus is offline tinitus  Europe
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midrange
with your words, it tames the impedance rise
inductors gets more effective(bigger) with lower impedance
and, gets smaller with higher impedance
the result of rising impedance is a less effective inductor
tho your 2mH is quite big
you might want a smaller zobel, to be only effective at higher frequency, in the upper midrange passband

in any case, in this kind of simple filter, the zobel have positive effect in regards of phase
but needs to be very finely adjusted to do this
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Old 1st November 2012, 11:52 AM   #42
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Actually the inductor on the tweeter is .2mH...quite small...and the tweeter has a built in LCR network in it already...I think that's what Steve was counting on...

Yesterday though, I reversed the polarity and had really good results...tamed that midband energy...so that means the series RC network is running on the negative side of the tweeter...

In Steve's xover, the tweeter is reversed already...I'll keep it like that for this trial and report back...

I'm hoping parts will be in early next week
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Old 1st November 2012, 12:14 PM   #43
tinitus is offline tinitus  Europe
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paralel inductor on tweeter cuts the lowest frequencies from the tweeter
in paralel its function is the opposite as to being in series
the same goes for caps
as for the tweeter 0.2mH being quite small, yes
means it cuts early
Dissi's 0.3mH looks more right, or normal

there is no standard one size fits all, ofcourse not
but with this filter some components and values are often very similar
but ofcourse always a little different
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Old 1st November 2012, 12:23 PM   #44
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Sideways, someone asked before but I will ask again. Is there any chance of posting your frd and impedance measurements of your drivers? If you can't do the simulation yourself, I'm sure there are others who would be happy to plug them in and give them a run.

I'm not sure if PCD was one of the sims you tried, it is great as you can see the results in real time as you change things, you need microsoft excell to run it though. Loudspeaker Design Software I personally use PCD for getting in the ball park, and then change over to speaker workshop to do optimisations.

Tony.
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Old 1st November 2012, 12:28 PM   #45
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K...understand now about what you are saying...that wouldn't be hard to tweak afterwards...and I think the reason it is cutting out early is because we are basically letting the Morel run it's course naturally...

Hey Tony

I do actually have PCD but I couldn't figure it out enough to work LOL!!! And they say the DEQX software is complicated...it was a walk in the park in comparison for me...must be because I'm old...I like wizards
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Old 1st November 2012, 12:33 PM   #46
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there are a lot of places to put things in PCD I will admit it's knowing which ones that are important that helps a lot. If you do your measurements on a single axis (ie not on axis with each driver, say half way between the two) then you don't have to worry about all of the offset stuff, and you just start off with a standard network. and go from there.

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Old 1st November 2012, 03:41 PM   #47
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I'd like to know how Dissi arrived at that 2nd order crossover really. It could be very good, but I wonder what sort of data it was based and what considerations came into it. sideways wanted something low order initially but I thought the tweeter looked awkward on first order and overlapped with the bass badly, hence the second order treble. The bass might be good on a single coil because it has little cone breakup.

This is all guesswork really since Morel don't make it easy. The Visaton tweeter is an unusual beast with built in LCR correction of Fs resonance, but it also has an odd frequency response when you filter it as a result. You probably wouldn't go far wrong with the generic Visaton 3kHz crossover and a bit of padding, but time will tell.

Meantime two interesting things to read. Thanks to wintermute's knowledge of Morel.

Lynn Olson on the problems with first order filters and "LGWAG" speakers:
Can you have sparkling treble but without sibilance
All his posts in that thread are enlightening as usual.

Secondly, the MOREL lowdown, why they are not for tightwads and why we (well, all except sreten and Zaph...LOL) like them:
LDSG - Morel recommendations
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File Type: jpg Visaton_3000Hz_Generic_Crossover.JPG (35.1 KB, 58 views)
File Type: jpg Aequal_root2_Steen_Duelund_filter.JPG (34.6 KB, 56 views)
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Well, there it is! Best regards from Steve in Portsmouth, UK.
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Old 1st November 2012, 04:45 PM   #48
Dissi is online now Dissi  Switzerland
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I have two independent measurements of the Morel HU 621: manufacturer data sheet and HobbyHiFi 6-2007 (german loudspeaker magazine). Both are quite similar. I'm very sorry to say, but the driver has a series of perturbations starting from 1.5 kHz and is actually better suited as woofer in a 3-way. For that reason and to get a better phase at 2.2 kHz, I did choose a 2nd order low-pass.
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Old 1st November 2012, 05:18 PM   #49
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Quote:
Originally Posted by wintermute View Post
(ie not on axis with each driver, say half way between the two) then you don't have to worry about all of the offset stuff,
While a single axis is true, typically you measure on the tweeter axis, not in between. You would not extract phase on the single-axis measurements.

If you use individual measurements of each driver's axis, you can then extract phase and take advantage of the Power Response, off-axis sliders, and different listening axis if you like. You do have to enter offsets, but this makes the tool more versatile than a single-axis design.

Later,
Wolf
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Old 1st November 2012, 06:14 PM   #50
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For a single axis, you would measure on the intended listening axis, whatever that may be. If you take a combined response on the same single axis, you can enter the physically-measured y-offsets, overlay the combined measured response with the PCD summed response of the other two measurements, and objectively determine the true z-offset by getting the summed response to match the measured combined response. Phase and the off-axis sliders remain useful tools with a single-axis measurement when done this way, as long as you aren't measuring from too close.
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