Lowpass Necessary?

CarlosT · 17th December 2006, 10:02 PM

Another unloved child from the Full-Range...

I just bought some full-range Audax 5.25" drivers and the tweeter already has a high pass cap. The vendor recommended that I leave things alone since the woofer would "naturally roll off" and would not need a low pass filter. Does this sound right? Would the woofer not waste energy and sound muddied "naturally rolling off" without a lowpass filter? Sounds simple enough for a little driver.

Here are the specs

http://www.madisound.com/pdf/audax/vp130g2.pdf

Do you guys buy this natural rolloff concept? Would it sound better with a simple first order lowpass coil?

Cal Weldon · 17th December 2006, 10:41 PM

Hi Carlos,

If Audax designed it that way, it probably sounds fine. Keep in the mind that the impedance of the woofer rises with the frequency so it might not be wasting the power as you suggest. How do you like them?

phreeky82 · 17th December 2006, 11:28 PM

i let my 8" cheapos naturally roll off and it sounds fine.

such speakers only sound "muddied", as you call it, because they are rolling off and only playing the lower frequencies.

just a cap would give a shallow drop off on the tweeter and lower freq and may well match the woofers natural roll off quite well.

i'd recommend you give it a go and see what it sounds like for yourself. is it going to be all that hard to change it afterwards if you don't like the result?

CarlosT · 18th December 2006, 02:26 PM

Thanks. Because of other complications and for simplicity, I'm also evaluating using a nice Vifa single midwoofer with no crossover or anything. See my related "Kids Boombox" thread.

17th December 2006, 10:02 PM	#1
CarlosT diyAudio Member Join Date: Oct 2006	Lowpass Necessary? Another unloved child from the Full-Range... I just bought some full-range Audax 5.25" drivers and the tweeter already has a high pass cap. The vendor recommended that I leave things alone since the woofer would "naturally roll off" and would not need a low pass filter. Does this sound right? Would the woofer not waste energy and sound muddied "naturally rolling off" without a lowpass filter? Sounds simple enough for a little driver. Here are the specs http://www.madisound.com/pdf/audax/vp130g2.pdf Do you guys buy this natural rolloff concept? Would it sound better with a simple first order lowpass coil?

17th December 2006, 10:41 PM	#2
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	Hi Carlos, If Audax designed it that way, it probably sounds fine. Keep in the mind that the impedance of the woofer rises with the frequency so it might not be wasting the power as you suggest. How do you like them? __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting

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17th December 2006, 11:28 PM	#3
phreeky82 diyAudio Member Join Date: May 2003 Location: Townsville, Australia	i let my 8" cheapos naturally roll off and it sounds fine. such speakers only sound "muddied", as you call it, because they are rolling off and only playing the lower frequencies. just a cap would give a shallow drop off on the tweeter and lower freq and may well match the woofers natural roll off quite well. i'd recommend you give it a go and see what it sounds like for yourself. is it going to be all that hard to change it afterwards if you don't like the result?

18th December 2006, 02:26 PM	#4
CarlosT diyAudio Member Join Date: Oct 2006	Thanks. Because of other complications and for simplicity, I'm also evaluating using a nice Vifa single midwoofer with no crossover or anything. See my related "Kids Boombox" thread.

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