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Old 2nd October 2006, 07:50 AM   #41
v-bro is offline v-bro  Netherlands
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maybe you can glue it in there under an angle...
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Max. cone displacement can be several foot on any speaker!Too bad it can be done only once......
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Old 4th October 2006, 10:15 AM   #42
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Ok new question. How do you regulate a speakers impedance through its frequency range? For example, this sub I threw on WinISD, peaks at 215ohms at 36.3hz.

What does that do for sound?
What does it do to the amp?
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Old 4th October 2006, 04:55 PM   #43
v-bro is offline v-bro  Netherlands
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It peaks on the resonance frequency, this is the frequency on which the cone takes the least power to move, still the frequency spectrum should stay even, because it only gets very little power on that freq.

Immagine it would stay an even load of for instance 8 ohms, the cone would simply pop out the basket when you play the resonance freq.

As the amp produces less power at higher impedance the combination of the dynamic loudspeaker and amplifier works! Providing the loudspeaker had been designed well.

The only thing it will do to the amp is giving it an easyer ride..

The effect of filter components between the amp and the drivers are much more dramatic. If you really want to screw up the soundquality use impedance correction networks (RLC network) in such a filter, or amplifier decoupling stages. The amp can "feel" a much greater load (and become hot!) from some type of filters.
But enough on that, explained before that I would advise to filter on the inputs of the power amp....

Input the driver impedance -to calculate the filter- the average impedance the driver shows round the crossover freq. and you'll be a lot more accurate on the calculations... ( just estimate this when reading the driver's impedance curve, most dynamic loudspeakers(drivers) have one or two peaks in the curve round the res.freq. and the impedance will mostly rise up to the higher freqs).

Dunno if you can read through this, hope I've been helpfull....
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Old 4th October 2006, 05:43 PM   #44
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A passive crossover for a sub is just not worth considering, for the reasons you are discovering. But wait until you see the size (and price) of the inductors required.
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Old 4th October 2006, 07:59 PM   #45
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Quote:
Originally posted by v-bro
Dunno if you can read through this, hope I've been helpfull....
It helped a lot, thanks. That spike to 215ohms made me nervous because I knew I would lose a lot of power, but since it wont effect my FR and just gives the amp a break, I am all for it!


Quote:
Originally posted by richie00boy
A passive crossover for a sub is just not worth considering, for the reasons you are discovering. But wait until you see the size (and price) of the inductors required.
Yeah, I'm not considering anything passive, because like you said, the components would cost way too much. I bought a Behringer DEQ2496 that I will use as my sub preamp/eq/xover.

Boosting with an EQ increases your group delay, correct? Cutting, however, should be just fine?
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Old 4th October 2006, 09:16 PM   #46
v-bro is offline v-bro  Netherlands
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Passive components are only expensive when they have to filter the hurricane-size power amp-out signal(to the speakers).
I am currently listening to a 4.60 US dollar (subwoofer) filter that works just fine!

Many people misunderstand that the values needed to filter line-signal (very low current/voltage signal this is!) are so small that even when you filter very low freqs the size and price of even the most exotic is still very small...

Even the very best of filters like the marchand xm46 (24db/octave) cost only 65 dollars per channel for a kit. (no matter the XO freq.)

http://www.marchandelec.com/ftp/xm46man.pdf

http://www.marchandelec.com/xm46.html (look at the specs!!)

They also custom build them!(but this one can be built for under 20 dollars for sure)....

Funny thing is, I asked people on this forum whether they would know the schematic for this one, nobody came up with this link.
I just found it myself (strangely enough it must've always been there....).
I can tell you my neighbours have heard me cheer for sure!

The filter appears to be more basic than I even thought, you can make any type of filter this way for very little buck.

And as this one is LC instead of RC (I'm currently using with 10db insertion loss) the losses will probably be very minimal....

Gonna build this one real soon!

Keep ya'll posted..
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