Topic: Amplifier for SUBWOOFER

[JojoD818]

is_otam_ap,

ang hirap naman i-type ng handle mo.  anyway, minsan kapag ang singer ay lalaki at malalim ang boses talagang may sumasabit pa din na kaunting low freq voice. pero ako hindi ko na naiintindihan yun sinasabi pag sub lang pinakikinggan ko. 

pero you are in luck, dalawa na ang versions ko ng aking sub filter. isang simple at siyempre isang hindi simple. pero pareho lang madaling gamitin. 

eto yun bago version under testing pa sa lab. (hataw, may lab na ako)





yun first version hanap ko pa picture.

 

[is_otam_Ap]

 JojoD818
  sir pa PM naman ng price nung both simple and not simple  i'm very interested dito... paki pm na rin yung spec kasi sa 4ohms 100 watts pa taas ko po ito gagamitin salamat sa reply

[is_otam_Ap]

May supply ba itong nasa pic or input lang yun from amplifier?

[av_phile1]

If you can design a filter with a steep roll-off, say 24db per octave, that should greatly minimize hearing vocals from the sub.  Even if you put the cutover far below the threshhold of even the deepest human voice, if the roll-off is not steep enough, you can still hear that voice.  I think that's the problem with some first order filters.  6db per octave gives a very gentle roll-off so you can hear much  of the filtered frequencies even at moderate volumes.  But a steep filter is quite complex.

[JojoD818]

exactly, that's why some vocals still passes through. but as I said, if the vocals approaches or goes below the cut-off then you will surely hear it though it would be "unintelligent".

the one in the picture has 3 separate 12dB LPF cascaded for the cut-off frequency barrier, not including another adjustable 12dB LPF. the first 3 LPFs ensures that only the LPF with adjustable frequency passes through.

i think my website has one of my old 48dB Linkwitz-Reiley/Sallen Key LPF designs. however the F3 is fixed so no user adjustable frequency. kinda limited really.

May supply ba itong nasa pic or input lang yun from amplifier?

the red box is my dual rail bench psu and the rca are for input and output.

[rascal101]

If you can design a filter with a steep roll-off, say 24db per octave, that should greatly minimize hearing vocals from the sub.  Even if you put the cutover far below the threshhold of even the deepest human voice, if the roll-off is not steep enough, you can still hear that voice.  I think that's the problem with some first order filters.  6db per octave gives a very gentle roll-off so you can hear much  of the filtered frequencies even at moderate volumes.  But a steep filter is quite complex.

Just to add, you need at least an L-C filter to ensure you have steep roll-off. If you want a quickie, what I do is

+-----+inductor+-----------+------------+
                                      |                  |
                                 resistor              |
                                      |            capacitor
                                 capacitor            |
                                      |                  |
+--------------------------+------------+

You need to do some computation. Better get a college textbook or have some simulation software ready. That way it saves you from the hassle of the calculator.

Rascal101

[JojoD818]

rascal101,

are you proposing a passive filter in an active sub?

[rascal101]

I'm just proposing a filter before the sub-woofer circuit (amplifying device).

[is_otam_Ap]

parang nabasa ko na ito sa forum  kaya lang hindi ko na mabalikan  :'( ang alam ko meron ditong website na may computation ng filter circuit...

[JojoD818]

I'm just proposing a filter before the sub-woofer circuit (amplifying device).

i don't get what you're saying. 

you are proposing a filter before the sub-woofer circuit, which circuit? mine?

[hattori_hanzo]

Finally a subwoofer that is worth a penny hehehe! (Joke) just recently aquired a sub from a fellow Pdvd for only 4.9k (DTX 4.15) at makinis pa and not been repaired, sana maganda ang performance. my proposed 21" is now a dream again  :'( ....

Anyways got a good review from the DTX 4.15 and so far its meeting my demand (played Zorro 2 and jurassic park) the explosion from the "nitro glycerin" is really making things in the room move. I set it at 50Hz on a 9oclock volume. using the Yamaha RCA subwoofer output and using only LFE, and it really blew me. parang yung na ramdaman ko sa THX theater sa makati...

Then while playing Jurassic, T-rex foot steps literally vibrates the windows, kailangan na ciguro mag upgrade ng room acoustics hehehe!...

while playing audio, the sub seems so quite and retaining the 2ch Euros 8 towers sound, just the way I like it... parang the sub works only on HT while playing audio cd's the only 5 channels are singing...

Thanks kay sir Porky...     

Anyways maganda pala itong DTX 4.15 so far ...

[ATJr.]

my proposed 21" is now a dream again   ....

wow!!!! dream ko rin yan..

[is_otam_Ap]

I change my mind... instead of sub filter equalizer na lang bibilin ko hehe