What's powering passive sub-woofer on a 5.1 or 7.1 AVR setup?

[happy hopping]

I am reading the manual of a mid end Denon AVR. Their sub-woofer out is just an audio signal. No actual power is given to send to the sub-woofer. Now, Focal has release a fancy passive sub-woofer.

SUB Utopia EM Colour Evo - Stackable high-definition subwoofer | Focal

SUB Utopia EM Colour Evo, Stackable high-definition subwoofer : enjoy the beauty of sound in the comfort of your own home with our Focal high-fidelity speakers. They reproduce the essence of music to delight the most demanding music lovers.

www.focal.com

if this sub-woofer is part of a 5.1 chnl. setup on a AVR, how does the sub-woofer gets its power?

 

[staticV3]

AVR->RCA->Monoblock Amplifier->Subwoofer

 

[Redacted]

Or just buy one of the hundred subs with a perfectly good built-in amplifier (usually Class-D) and a DSP for the crossover.
In any case, you'll need to blend in the sub with all the other speakers, which will either be a manual process or automated with some room correction tools.

 

[happy hopping]

Or just buy one of the hundred subs with a perfectly good built-in amplifier (usually Class-D) and a DSP for the crossover.
In any case, you'll need to blend in the sub with all the other speakers, which will either be a manual process or automated with some room correction tools.

I have 1 of those. The problem is some sort of ground loop humming sound. I don't know if that only happen to cheap sub-woofer, or any active power sub-woofer

 

[happy hopping]

AVR->RCA->Monoblock Amplifier->Subwoofer

so the timing of ea. signal is still going to be accurate? still controlled by the AVR?

on that link, there is a manual, the manual talks about a "power supply". Do they mean monoblock? or is there some sort of dedicated power supply? as the diagram in the manual shows a little power supply the size of a clothing iron

 

[Redacted]

I have 1 of those. The problem is some sort of ground loop humming sound. I don't know if that only happen to cheap sub-woofer, or any active power sub-woofer

Fix the ground loop* (if it's not just a fault in your specific sub or amp)! Much cheaper than buying new gear. And FWIW, my two powered subs are silent.

*My guess is you may also have other kit in circuit, maybe a turntable?

 

[happy hopping]

Fix the ground loop* (if it's not just a fault in your specific sub or amp)! Much cheaper than buying new gear. And FWIW, my two powered subs are silent.

*My guess is you may also have other kit in circuit, maybe a turntable?

no, I don't have money to buy any new sub-woofer. So I just put up w/ the humming sound

 

[Redacted]

so the timing of ea. signal is still going to be accurate? still controlled by the AVR?

Timing will be fine. You won't notice with subs anyway.
[Your AV arrangement seems like it has amps for the main speakers, but the bass-out port is not (yet) amplified, so adding a monoblock to power a passive sub, or using a sub with the amp built-in is likely adding a similar delay to the amps in the AV - get me?]

A class-D monoblock that is good enough to power a sub can very cheap. Say £50 cheap.

 

[Redacted]

So I just put up w/ the humming sound

I'm only saying that a bit of work is needed to figure out the reason for the hum. It may or may not be fixable with your present gear, but if you are happy with the hum, then no worries. If you don't want the hum, post a drawing of your gear showing hows every item connects - someone will be along to suggest things!

 

[happy hopping]

I have the AVR connects by basic copper wires to the front, left, right and rear right + left. Then I have a simple sub-woofer 20 to 25 ft. cable connects to the sub-woofer. The whole setup is 5.1. The brand is Klipsch.

the AVR is easily several hundred watt, so I have it connect to an independent wall plug because whenever I turn on the AVR, I don't want a drop in voltage affects the other equipment in my PC room. As such, the AVR circuity is NOT part of the sub-woofer circuit.

Now someone told me to avoid ground loop humming, they have to be in the same circuit. So as a test, I did connect the sub-woofer power plug to the AVR wall plug. No difference.

That's it. It's a very simple 5.1 setup.

 

[Kal Rubinson]

SUB Utopia EM Colour Evo - Stackable high-definition subwoofer | Focal

SUB Utopia EM Colour Evo, Stackable high-definition subwoofer : enjoy the beauty of sound in the comfort of your own home with our Focal high-fidelity speakers. They reproduce the essence of music to delight the most demanding music lovers.

www.focal.com

Wow. A passive (w/o power amplifier) subwoofer that still requires an AC source for EQ. Poor feature set.

 

[Spkrdctr]

The problem you having is that having a passive sub is not a modern type of sub. You have the choice of either getting a new sub (or used) that has its own power (which is 95%) of them or buy a powerful class D amp as the spec sheet said it can use up to 1000 watts. So, if possible I would go with a modern powered sub if you can't then look for a 1000 watt class D amp. Let us know how you end up setting it up. Sorry to hear about the humming issue. I know you will get it all set up even it takes a bit of fussing with it.

 

[EngineerNate]

Very mostly all pro-sound subs are powered by separate amps in a rack somewhere not colocated with the subwoofer itself.

There is no delay or timing issue associated with this vs the amp living inside the same box as the speaker driver. Electricity travels at the speed of light for all practical purposes. Interconnect lengths do no impact timing in any measurable way.

 

[staticV3]

so the timing of ea. signal is still going to be accurate? still controlled by the AVR?

Yes. Amplifiers do not add meaningful delay.

 

[Redacted]

Yes. Amplifiers do not add meaningful delay.

Only 5-20ms apparently (Wikipedia); probably less for a basic power amp, but with subs, nobody cares.

 

[Kal Rubinson]

Only 5-20ms apparently (Wikipedia); probably less for a basic power amp, but with subs, nobody cares.

Not so for analog amps, afaik.

 

[Redacted]

Not so for analog amps, afaik.

OK - I have no measurements. Just going by wiki.
What measurements are available?
My cheap oscilloscope is single channel, but if someone is willing to check the numbers, it would be interesting.

{and what are you saying is an analogue amp?]

 

[Ruediger]

A class-D monoblock that is good enough to power a sub can very cheap. Say £50 cheap.

It's a 13" sub and they recommend 500-1000W.

It's just 17k € - buying a decent poweramp could be expected.

When I match a sub with front-left on a desk I get 8ms added to front-left from that measurement. It makes no sense to me when looking at amps. Front-left goes to poweramp, sub out goes to plateamp in the sub. No extra appliance. It's probably the room/measuring position.

 

[Redacted]

I can't say I understand the OP setup, or what he needs to get done!
I'll leave it to the experts on ASR.
Anyone on a budget can check these kind of things out:

Xnuiasqe HIFI Sound Amplifier 1000W Power Amplifier Speaker Amplification Mono Digital Audio Amp Home Theater: Amazon.co.uk: Electronics & Photo

Free delivery and returns on eligible orders. Buy Xnuiasqe HIFI Sound Amplifier 1000W Power Amplifier Speaker Amplification Mono Digital Audio Amp Home Theater at Amazon UK.

www.amazon.co.uk

 

[Kal Rubinson]

{and what are you saying is an analogue amp?]

A tube- or transistor-based analog power amp. No controls/processing.
Class-D power amps begin to introduce some but still negligible latencies.