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Amplifier Wattage With/Without Subwoofer

fohrums

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Hello Audio Science Review Folks,

I do not understand the Amplifier/Receiver Wattage differences when a subwoofer is used and when it is not. Besides knowing the rating of the speaker/subwoofer combination in terms of wattage for the appropriate amp are there anything else to consider?

When a subwoofer is included with a stereo speaker setup, is the the amp's power reduced?
 

Doodski

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The amps power is not reduced but it might be divided up differently to the various speakers depending on what system type you have. What do you have?
 
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fohrums

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Sure, my Audio Equipment are the following:

Audiovideoreceiver (or avr): Pioneer-vsx-1022
Speakers: Sony-sscs5-speakerbookshelfpair (6-ohms; 100w)
Subwoofer: Sony-sacs9-subwoofer (6-ohms; 115w)
 
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fohrums

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That is an extremely difficult read. Someone did end up saying - "Passive subwoofer filters (for the sub OR satellites) do not really work (post no. 42)." My style of listening is ipod at 75% volume and speaker at 30% to 75% in laymen's terms, because that has always seemed to prevent damage from my personal experience of what I consider something sounding dangerous from distortion/clarity.
 
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fohrums

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Pls. allow me to continue this discussion by asking another question in regards to Amplifiers/Speakers. This next question is about Power-ouptut via RMS/Dynamic (continuously safe vs. max total wattage capability). Let me know if "Dynamic-poweroutput isn't defined as Total-poweroutut".

The question is, for an amp that's 100w-rms & 150w-dynamic paired with a speaker that's 100w-dynamic safe to run in combitation with a subwoofer that's 120w-rms?

This is where I am confused about wattage total'ing because my subwoofer requires more power than my speakers. I will be helpful to clarify what i'm talking about, if needed.
 

FrantzM

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Hi

There is some truth to it. The majority of the power sent to a multiple drivers loudspeaker is spent in the woofers. If the woofer is asked to reproduce low bass ( things below 100 Hz) this tend to require more power. Using a subwoofer in a way where you send all the bass below 80 Hz (meaning you crossover at 80 Hz) to the subwoofer and the rest upward of 80 Hz to the main speakers, alleviates, even removes that load from the main amps which has now to send power to reproduce 80 Hz to 20,000 Hz.. which often is less than the power required to reproduce sounds below 80 Hz at substantial levels...
Oversimplified but I hope you get the gist of it ...
 

Another Bob

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To jump right to the bottom line, yes, your combination of equipment is "safe". In a more general sense, except in rare circumstances (that I don't think apply here) you will hear significant distortion before equipment damage from excessive volume occurs.

You don't really need to be concerned about "wattage total'ing". The subwoofer amplifier is independent of the amplifier in the receiver, and the efficiency of the subwoofer (how much sound power is generated per watt of amplifier power) will be different from your main speakers, which is part of the reason the subwoofer amplifier has its own volume control - to adjust for this mismatch.

You don't say whether you are connecting your subwoofer via the high-level (speaker wire) or line-level inputs. My recommendation is to use the line level (the pre-out on your receiver) and set your speaker size to "small" in the receiver's setup. This will prevent the very low bass signals from going to your main speakers, which has 3 benefits: 1) it reduces distortion in the main speaker, especially in the case of speakers with small woofers, like the 5" drivers in yours; 2) it reduces the load on your receiver's amplifier (this gets to the issue I originally thought you were asking about); 3) it minimizes overlap between the main speakers and the subwoofer, i.e., frequencies where both are playing, which can cause uneven response due to reinforcement or cancellation between the two.
 
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fohrums

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You don't really need to be concerned about "wattage total'ing". The subwoofer amplifier is independent of the amplifier in the receiver, and the efficiency of the subwoofer (how much sound power is generated per watt of amplifier power) will be different from your main speakers, which is part of the reason the subwoofer amplifier has its own volume control - to adjust for this mismatch.

There's amplifiers in subwoofers? My subwoofer does have those options of controlling volume by a gain knob and crossovers for high/low pass (3-knobs total). Since the crossover is on my subwoofer and not on my speakers wouldn't that limit the sound to the subwoofer only and not the other way around to the speakers?

You don't say whether you are connecting your subwoofer via the high-level (speaker wire) or line-level inputs...

I plan to use line-level for my next setup, but now I have it as speaker wire like so (notice high-level plugging from subwoofer to speaker as my sub has this capability):

Amp's Output -> Subwoofer Input / Subwoofer-out -> Speaker Input
 

Beershaun

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Yes. Your subwoofer has it's own built in amplifier. So it's not being powered by your receiver. The receiver has it's own crossover built in. So you should turn the crossover on the subwoofer up to the highest frequency it will go. You should let the receiver do the crossover work. that will avoid accidentally creating gaps in your frequency range between the receiver's crossover frequency and the subwoofer's crossover setting.

Use the "subwoofer pre-out" on your receiver to connect the sub. that way the receiver can manage the crossover.

https://www.sony.com/electronics/home-cinema-speakers/sa-cs9

https://www.pioneerelectronics.com/...ome/VSX-822-K_OperatingInstructions062612.pdf
 

Chrispy

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There's amplifiers in subwoofers? My subwoofer does have those options of controlling volume by a gain knob and crossovers for high/low pass (3-knobs total). Since the crossover is on my subwoofer and not on my speakers wouldn't that limit the sound to the subwoofer only and not the other way around to the speakers?



I plan to use line-level for my next setup, but now I have it as speaker wire like so (notice high-level plugging from subwoofer to speaker as my sub has this capability):

Amp's Output -> Subwoofer Input / Subwoofer-out -> Speaker Input

Most commercial subwoofers use a plate amp with the controls you describe. Most recievers are not capable of providing an amp channel for subs either (some HTIB setups do use such, tho). Probably only a low pass filter on your sub, tho...and if using bass management in your receiver then this should be maxed out or bypassed. You can use high level connections but if you have a bass managed sub pre-out that would typically be preferable.
 
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fohrums

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This is good to know, guys! Let's just say I am selling my current amp for a new one that's for stereo listening. With that said, with my subwoofer having it's own built-in amp do I now only need an Amplifier to match my Bookshelf Speaker's wattage instead of the subwoofer or should it match for both? Does this relate to what the plugging method is being either line-level or high-level? Thought I'd share this following video from someone who calmy explains things soothingly:
He just uploaded this recently and basically said that high-level is his preference by design. But, i've heard from this thread and even elsewhere to use line-level. I would love to understand the differences in terms of how I plan to upgrade my Pioneer amp for a Yamaha one with my speakers/subwoofer.

If your curious, the amp I plan to get is the Yamaha A-S501 ($550) or the Yamaha A-S801 ($900). Besides the the price difference of the two being 350-dollars - another difference is that the AS801 has built-in DAC that is supposedly really high-quality.

What out of the two amps will be a really awesome choice?
 
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Chrispy

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What does match your bookshelf power ratings even mean? Speaker wattage ratings are some of the most useless specs for a speaker IMO. Might warn you as to its limits but why would it dictate your amp choice particularly? You never plan to change speakers so you customize an amp purchase just for one use? Not me, and have no use for integrated amps outside of multich avrs. If I were going two ch only again I'd stick to separates myself, tend to get more capable amps that way and more flexibility for the rest.
 
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fohrums

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What does match your bookshelf power ratings even mean? Speaker wattage ratings are some of the most useless specs for a speaker IMO. Might warn you as to its limits but why would it dictate your amp choice particularly?

Isn't it because there is such thing as over-powering speakers to the point of damaging them?

You never plan to change speakers so you customize an amp purchase just for one use? Not me, and have no use for integrated amps outside of multich avrs. If I were going two ch only again I'd stick to separates myself, tend to get more capable amps that way and more flexibility for the rest.

Is this about separates in regards to Amp/Audioprocessor in combination as opposed to just using only an amplifier w/out the audioprocessor? If not can you give an example of what you mean by "Separates"?
 

Chrispy

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Isn't it because there is such thing as over-powering speakers to the point of damaging them?



Is this about separates in regards to Amp/Audioprocessor in combination as opposed to just using only an amplifier w/out the audioprocessor? If not can you give an example of what you mean by "Separates"?

With judicious use of a volume control not likely you'd be over powering them. If you don't trust yourself some units allow you to set a limit on the volume. I regularly use amps that could damage various speakers, but I don't....

An integrated amp is a combination of a pre-amp and amp generally, a receiver added a tuner; a modern avr is more about pre-amp/processor for audio and video, with on-board amplifiers and internet access. Separates is generally separating the pre-amp (or pre-processor) and amplifier and using specialized units otherwise (like a radio tuner way back when....internet access has largely made that not too interesting). An integrated amp can be a one box solution, if it has all you need.....
 
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RayDunzl

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Isn't it because there is such thing as over-powering speakers to the point of damaging them?

There is, but I never have, and prefer "big" amps.
 

Chrispy

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Also, you can take an amp with "ratings" within your speakers's capabilities but drive that amp beyond that rating into higher distortion levels and power levels.
 
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fohrums

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Back at it folks :cool:

Also, you can take an amp with "ratings" within your speakers's capabilities but drive that amp beyond that rating into higher distortion levels and power levels.

I understand this regarding damaging amps by too high of volume leven to the point of continuous distortion (along with what RayDunzl saying it vice-versa with speakers damaging due to high volume levels).

...But, i've heard from this thread and even elsewhere to use line-level. I would love to understand the differences in terms of how I plan to upgrade my Pioneer amp for a Yamaha one with my speakers/subwoofer.

This was not yet explained regarding line-level vs. high-level plugging for subwoofer to amp cable hookup. Let's start by me asking which is considered legacy and why would one be preferred over by design and purpose?
 

Beershaun

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Line level is the unamplified signal being sent out for an outboard amplifier. Typically this is via RCA output labelled "subwoofer" or "preamp out." Modern AVRs and integrated amps have built in digital signal processing and crossovers that allow you to split the signal between your main speakers and a subwoofer. It can apply filtering to remove low or high frequencies from the signal and adjust the time delay between the main speakers and subwoofer to match them up so they sound like one speaker.

High level outputs are your fully amplified speaker outputs that you connect to passive speakers. Some amplified subwoofers have high level speaker inputs so they can take the exact same signal your main speakers take in with damaging them. This can be useful if you are just using an amplifier and have no preamp or dsp to split the signal before amplification.
 
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