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Powered Vs. Passive Subwoofer

Johnny Salam

Johnny Salam

JohnnySalami
I have a pair of 2-way Genisis bookshelf speakers running from a Nikko 3220 (which I may swap with either a Scott 335 or a Marantz 2200B) in my bedroom.

I would think a passive sub would be better because the crossover solves the problem of the small speakers in the Genisis trying to do the bass, and with the vintage reciever there isn't a subwoofer out.

Am I full of it? What are the advantages of powered subwoofers, especially with a more powerful amp in a bigger room?
 
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A powered sub gives you much more flexibility in balancing the sub with your other speakers. You can tune the volume level and also the crossover frequency that balances best with your satellites.
With a passive sub you have to design the crossover exactly right to accomplish the same thing. There's no adjustment unless you go back in and alter the passive components.
 
The powered sub will have a built-in crossover in the plate amp- run the receiver's speaker "outs" to the "in" speaker wire connectors of the plate amp (most have them, if it's at least half-way decent) and then from the "out" speaker wires to the Genesis speakers.

Many passives I've seen don't feature a built-in crossover on them- this includes, if I am remembering correctly, my NHT passives and my 3D acoustics passive.

I am either going to run a subwoofer external crossover from one of the two rca pre-outs on my pre-amp to a separate full-range amp, or use the second rca outs of my pre-amp to a dedicated sub amp that sits separate from the subs.


Benefits of a powered sub is less clutter, plug and play, easy-going.

Drawbacks are you're limited to that plate amp, sub must be able to plug into a wall outlet so sub must be close to one, and sometimes those plate amps bust, possibly due to vibration.

Benefits of a passive are you run whatever amp you want, where you want, and some external crossovers allow you lots of adjustment.

Negatives are you need room for that extra amp, and a fistfull of cables/wires to tie it in together.

But....


by bypassing the plate amp crossover, and using a high-end external crossover, you're allowing yourself some possible extra sound improvement.
 
My M&K passive sub has jumpers to crossover at different frequencies. it's a very good sounding sub. The down side of a powered sub is if the plate amp takes a dive you have a mess. The up side is much more adjustably (XO, phase, volume etc) and some even have a remote. :thmbsp:
 
Powered vs. passive

I've always looked at powered subs as, "This is it, there aint no more". Even when the sub is 'high-end', you're stuck with it's adjustments. Personally, I prefer passive because you can choose your own amp, crossover and equalization. Just a more flexible arrangement.
 
A powered sub works well with my vinatge amp. I run two shielded cables from the pre-amp out to the line in on the sub. I can set the crossover and level on the sub where I want to help out the low end of the mains (HPM-100). The CR 2020's pre-out is always "hot" and doesnt have to be jumpered to the pre-in.
 
Like 'um ALL...

I didn't mean to come off as being opposed to powered subs. Not at all. Sometimes, practicality dictates what type to use. I like powered subs as well. They ARE subs, afterall! Some out there will not use a sub, no matter how anemic their system may sound. To each his own. :thmbsp:
 
kfa888 said:
My M&K passive sub has jumpers to crossover at different frequencies...
Click to expand...

I didn't know that- pretty neat!

I should check my 3D Acoustics- I think, in retrospect, it actually might have a crossover for the other speakers to pass through.

The NHTs- I'll look at them too- but I'm still thinking with those it's all at the external amp (NHT sub amp)- a nice metal encased unit freestanding of the amp.


kfa888 said:
...The down side of a powered sub is if the plate amp takes a dive you have a mess....
Click to expand...


Agreed, though folk have been lucky to find replacement amps that fit.




kfa888 said:
...The up side is much more adjustably (XO, phase, volume etc) and some even have a remote. :thmbsp:
Click to expand...

This can also be achieved with external subwoofer crossovers- one of mine has phase, volume and crossover freq.
 
A passive sub basically is just an active sub minus the amp/crossover, so you can provide your own. And to the naysayers or those who don't know, their are some killer passive subs out there. Case in point, my NHT W1's have a separate active crossover and amps, so its really an active subwoofer system that's packaged differently.
 
It's all how you see it...

Inspiribomb said:
A passive sub basically is just an active sub minus the amp/crossover, so you can provide your own. And to the naysayers or those who don't know, their are some killer passive subs out there. Case in point, my NHT W1's have a separate active crossover and amps, so its really an active subwoofer system that's packaged differently.
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Excellent way of looking at it. :thmbsp:
 
Passive subs with suitably low xover point are good- if efficient enough! The very large inductor(s) needed to gain the low xover point will take a fair amount of power to just push the signal through! If you have a beefy enough amp to drive a quality passive at low oxover points, like 40~80hz, then there you go!
Personally I really like the older Velodynes "CT" series active subs. Built like tanks and sound very good and getting cheaper all the time!
DC
 
Clean, clean, clean.

Then there are those of us who rely solely on the electronic crossover/EQ to dictate what signals go into the amp, then into the subs themselves. This is a very clean and efficient method of marriage between driver and source. Nothing :nono: stands between the beast and it's food. :thmbsp:
 
dc270 said:
Passive subs with suitably low xover point are good- if efficient enough! The very large inductor(s) needed to gain the low xover point will take a fair amount of power to just push the signal through! If you have a beefy enough amp to drive a quality passive at low oxover points, like 40~80hz, then there you go!
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I keep reading that about passive crossovers here on AK, but it's just not true.

According to the PE component selection chart, for a 75 Hz single-pole lowpass, you need a 17 mH inductor with an 8-Ohm woofer, or half that for 4 Ohms. In Erse Super Q, the DCR is 0.515 Ohms. The loss in the inductor is a HUGE 0.54 dB.

The REAL problem with this approach is balancing with the "satellites." They have to be more efficient than the sub(s) and padded down to match. Sometimes you get lucky, though, with specific speaker combinations, and it's not necessary to do that at all.

Active solves all of that, if you have a second amp to dedicate to sub duty. An active crossover is less than $100 to buy or build for the purpose.... :yes:
 
Zilch said:
...Active solves all of that, if you have a second amp to dedicate to sub duty. An active crossover is less than $100 to buy or build for the purpose.... :yes:
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Forgive my ignorance on this, but when you say active crossover, are you meaning powered? I'm not following 100%.

I've got a powered external crossover, and a crossover that's external but not powered. Both have phase, volume and adjustable crossover knobs, but one is passive (non-powered), one is powered.

I've been told the powered units are better by some folk due to gain, othesr say the non-powered models are better due to their simplicity.

:headscrat
 
Johnny Salam said:
. . . I would think a passive sub would be better because the crossover solves the problem of the small speakers in the Genisis trying to do the bass, and with the vintage reciever there isn't a subwoofer out . . . .
Click to expand...

I think you might misunderstand. A passive sub may remove the lows from the Genesis speakers. But.... most powered subs have variable crossovers and level controls. Many have line level inputs and high pass outputs to the amp for the higher frequencies.

But one of the best things about powered subs is their improved linearity. Using sensors to monitor the woofer movement and adjust for inaccuracies.
 
thedelihaus said:
Forgive my ignorance on this, but when you say active crossover, are you meaning powered? I'm not following 100%.
Click to expand...
I'm meaning that the sub is powered, by a separate amp, basically, with an external line-level crossover. It's possible to do that passively, as well, but uncommon.... :yes:
 
Zilch said:
I keep reading that about passive crossovers here on AK, but it's just not true.

According to the PE component selection chart, for a 75 Hz single-pole lowpass, you need a 17 mH inductor, or half that for 4 Ohms. In Erse Super Q, the DCR is 0.515 Ohms. The loss in the inductor is a HUGE 0.54 dB.

The REAL problem with this approach is balancing with the "satellites." They have to be more efficient than the sub(s) and padded down to match. Sometimes you get lucky, though, with specific speaker combinations, and it's not necessary to do that at all.

Active solves all of that, if you have a second amp to dedicate to sub duty. An active crossover is less than $100 to buy or build for the purpose.... :yes:
Click to expand...

Zilch said:
I'm meaning that the sub is powered, by a separate amp, basically, with an external line-level crossover. It's possible to do that passively, as well, but uncommon.... :yes:
Click to expand...

Thank you. I've twin "outs" on my pre, so I can run the second outs to that passive or powered external crossover and amp combo.

Your time and response is much appreciated. Thank you.:yes:
 
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