Unpowered subwoofers are better than powered ones.

[Pyrrho]

Unpowered subwoofers are better than powered ones. There are several reasons for this:

First of all, you don't have the amplifier being so vibrated as one that is built into the cabinet, so the amplifier is less likely to fail. Second, if the amp ever does fail, it is much easier to replace if it is not built in. Third, you can select whatever power you want with it. If you have an old amplifier (in a receiver or whatever) that can handle the impedance of the subwoofer, you don't have to buy a new amplifier at all. With, for example, the unpowered SVS subwoofers, they are fairly efficient, and you may be surprised by how much bass you can get from a low powered amp. Remember, it takes a doubling of power to get just a 3 dB increase in volume, so if you had half the power of the installed amp, you would only lose 3 dB in possible volume (forgetting about peaks for a moment, which may mean you are less likely to miss anything, as you are unlikely to be constantly driving the woofer at maximum power), and you lose only 6 dB of maximum volume if you have only 1/4 of the power of the built in amp, and you lose only 9 dB of maximum volume if you have only 1/8 of the power of the built in amp. So even if your extra amplifier is not very high powered, you can still get good results. And, of course, you can select an amplifier that is as powerful as the built in one, or even more powerful, if you wanted.

Also, if you are using the subwoofer with a Dolby Digital surround system, your receiver/preamp/processor has a dedicated subwoofer output that deals with the crossover for you, so paying for a crossover built into the subwoofer is a waste of your money. So all you need is a power amp with a passive sub.

Fourth, many people experience difficulties with "automatic on" subwoofers. Those stupid auto signal sensing things are not a good idea, as it must turn on only AFTER the music starts. And then they shut off if the music is quiet for an extended period (or with a subwoofer only signal, if there is no deep bass for a while).

The solution to the problem is to buy unpowered subwoofers, use a separate power amp, and an automatic switched outlet strip, such as:

http://www.smarthomeusa.com/Shop/Sma...pecifications/

where one plugs in one's receiver or preamp into the "control outlet", and the subwoofer power amp into one of the automatically switching outlets. It works great. I know, I am using one of these strips with the power amp for my SVS CS-Ultra subwoofers.

With the setup I suggest, it turns on as soon as the receiver or preamp turns on, and turns off only when the receiver or preamp is shut off. So it does exactly what it should do, unlike those stupid signal sensing automatic on circuits.

I do not plan on ever getting another subwoofer with a built in amp. In my opinion, it is just asking for trouble.

 

[Pwner_2130]

Hold on just a second there are a couple advantages of powered subs:

- They do not require any extra knowledge or setup
- The well-made subwoofers offer extended warranties
- A powered sub allows for a lighter, less powerful, and therefore cheaper amplifier, which helps low-budget people into the hobby
- Powered subs can be used for any HT setup as long as the Amp has a subwoofer output.

 

[j_garcia]

My sub is passive but I still use a subwoofer amp designed to handle the demands of driving a subwoofer for hours on end. I have no problem with my auto on/off circuit.

Most subs include their own crossover because not all systems are exactly the same or have bass management; a compromise as with all things electronic to accommodate the variety of people and systems out there. Also having it self contained is actually a lot simpler and the vibration utlimtely doesn't affect the internal amp as much as you seem to suggest.

You make it sound like you've stumbled onto something that nobody else knows. The earliest subs were almost all passive.

 

[Pyrrho]

Hold on just a second there are a couple advantages of powered subs:

- They do not require any extra knowledge or setup

I don't think it requires any special knowledge to hook up a separate amplifier. The only added connection is between the amplifier and the speaker, and if one cannot handle doing that, one cannot hook up the main speakers to a receiver.

Unless, of course, one also wants the automatic on feature, in which case one must know how to use an outlet strip. Again, this is easy.

- The well-made subwoofers offer extended warranties

You can buy an extended warranty on just about anything. I will grant, however, that some well made subwoofers with built in amplification are likely to give years of trouble free service. But if they do fail, they are more of a bother to deal with.

- A powered sub allows for a lighter, less powerful, and therefore cheaper amplifier, which helps low-budget people into the hobby

As mentioned in the opening post, one may use a low powered amplifier with an unpowered subwoofer. And very many of us have an extra amplifier laying about (perhaps built into a receiver), so it can be cheaper to buy an unpowered subwoofer. Compare the SVS CS lines with the PS lines, and you will see that if you already have an extra amplifier, you can save quite a bit. And even if you don't, the difference in cost is enough that one can pick up a used amplifier (and with the higher end models, a new amplifier).

- Powered subs can be used for any HT setup as long as the Amp has a subwoofer output.

Any receiver or processor that has Dolby Digital in it has bass management built in, so any receiver with Dolby Digital can be used with an unpowered subwoofer with a separate amp.

 

[Pyrrho]

My sub is passive but I still use a subwoofer amp designed to handle the demands of driving a subwoofer for hours on end.

Any decent amplifier is designed to run for hours on end. What matters is that the amplifier be able to handle the impedance and be able to produce adequate power.

I have no problem with my auto on/off circuit.

You are lucky. Just do some searching in these forums, and you will find that many have problems with theirs.

Most subs include their own crossover because not all systems are exactly the same or have bass management; a compromise as with all things electronic to accommodate the variety of people and systems out there.

This is true, and can make a difference for 2 channel or very old surround systems. However, if one has Dolby Digital, one has bass management built into the receiver/preamp/processor.

Also having it self contained is actually a lot simpler

No, it is not a lot simpler. With an unpowered subwoofer, the only necessary added connection is between the amplifier and the speaker. And if one wants it to automatically turn on and off, then one will need to be able to handle plugging things into a power strip like the one for which I provided a link. This is not rocket science. If one can handle hooking up the rest of a surround system, one can manage these things as well.

and the vibration utlimtely doesn't affect the internal amp as much as you seem to suggest.

I do not mean to suggest that all built in subwoofer amplifiers are unreliable. However, the vibrations are not going to do it any good. You wouldn't put your receiver on top of your subwoofer, would you? Or stack your power amps on top of it, would you?

You make it sound like you've stumbled onto something that nobody else knows. The earliest subs were almost all passive.

I am sorry if it seems that way; it is not the impression I wished to give. If I were the only one to think of such a thing, there would not be manufacturers of unpowered subwoofers. Obviously, I am not the first person to think of unpowered subwoofers, or the advantages of them. However, I think a lot of people never give the matter any thought, because most subwoofers these days are powered.

 

[Seth=L]

Most people view less boxes as a positive. I would only get into passive subs if I was doing full blown separates. There are also many more active subwoofers available in the market today.

 

[Pyrrho]

Most people view less boxes as a positive.

I agree that, all else being equal, fewer boxes is a positive. It takes up less space to have the amplifier built in. And, as others have noted, it is a little easier to hook up (one less connection is required). Those are real advantages, and if one is in a tiny apartment, it might be necessary to go with what takes up less space.

But often things get better by having more boxes. I personally have had repeated troubles with built in amplification with a subwoofer, and have read too many posts in which people complain about problems that they have had with built in amplifiers in subwoofers to ever want to buy a powered subwoofer again.

I would only get into passive subs if I was doing full blown separates. There are also many more active subwoofers available in the market today.

Yes, the selection of powered subwoofers is greater. However, the highly regarded SVS has several models of unpowered subwoofers that are worth considering.

 

[Smarthomeusa]

Hey guys .. I don't mean to intrude. I'm the webmaster for smarthomeusa.com .. I just wanted to let you know that the link posted on this thread was somehow automatically shortened and therefore results in a 404. The page you wanted was

smarthomeusa.com/Shop/Smart-Energy/Item/LCG3/specifications/

Let me know if theres anything else I can do for you .. (including discounts

Thanks guys

 

[Buckeye_Nut]

Unpowered subwoofers are better than powered ones. There are several reasons for this:

First of all, you don't have the amplifier being so vibrated as one that is built into the cabinet, so the amplifier is less likely to fail.

For me, the entire argument falls apart right there. Any well-built subwoofer cabinet will provide the most vibration-free and stable platform for electronics in any theater room. The entire room and it's contents might be disturbed (if you failed to rattle proof the contents), but the sub itself should remain vibration free & rock solid.

If you must display expensive china in your theater....the safest place should be directly on top of the subwoofer

 

[j_garcia]

I have plenty of room so having an external amp doesn't bother me, however the space that my amp is taking up in my rack to keep it out of sight could still be used for other things...

You don't need a plug strip like the one mentioned, most external / pro amps have some sort of on/off mechanism these days, such as a 12v trigger or even signal sensing abilty like a sub amp.

 

[Pwner_2130]

I concur. I have yet to see a powered sub made with a cabinet that is susceptible to vibration.

 

[Pyrrho]

Unpowered subwoofers are better than powered ones. There are several reasons for this:

First of all, you don't have the amplifier being so vibrated as one that is built into the cabinet, so the amplifier is less likely to fail.

For me, the entire argument falls apart right there.

It is odd that you regard one reason that is independent of some of the others as being somehow necessary for the others. Regardless of the issue of vibrations, if the amplifier ever does need to be replaced, it is clearly easier to do when it is separate. Additionally, regardless of the issue of vibrations, with a separate amplifier, one may choose whatever amplifier one wishes. Regardless of the issue of vibrations, if one happens to have an acceptable power amplifier laying about, one can save money buying an unpowered subwoofer instead of a powered one (in cases where one has the option to go either way, as, for example, with SVS with their PC [powered] and CS [unpowered] lines). Regardless of the issue of vibrations, some people have experienced difficulties with the subwoofer automatic on feature. So why do you imagine that everything rests on the issue of vibrations?

Any well-built subwoofer cabinet will provide the most vibration-free and stable platform for electronics in any theater room. The entire room and it's contents might be disturbed (if you failed to rattle proof the contents), but the sub itself should remain vibration free & rock solid.

If you must display expensive china in your theater....the safest place should be directly on top of the subwoofer

So, in keeping with your theory, do you place your audio equipment on top of your subwoofer, or do you really not believe what you say?

The next time you use your subwoofer on something with loud, deep bass, I suggest placing your hand on top of the cabinet and observe whether or not you feel anything, and compare that with how it feels when the subwoofer is off.

 

[Gimpy Ric]

Too me, buying a sub without a built in amp would be like buying a Ferrari 430 without the engine. Sure, you could shoehorn a small block chevy in there, but hell, whats wrong with the 32 valve engine designed for it?

Non Powered subs are so '80's .

 

[Pyrrho]

I have plenty of room so having an external amp doesn't bother me, however the space that my amp is taking up in my rack to keep it out of sight could still be used for other things...

Very true. As already admitted, a separate amplifier takes up more space, which, in some cases, can be a problem.

You don't need a plug strip like the one mentioned, most external / pro amps have some sort of on/off mechanism these days, such as a 12v trigger or even signal sensing abilty like a sub amp.

Very true, with many amplifiers. However, not all have a 12v trigger, and then, if it is very powerful, such an outlet strip is useful. (Also, if the amplifier is very low powered, it might be possible to plug it into a switched outlet on a receiver, but one would want to be careful about the power consumption in such a case, so that one does not exceed the power rating of the switched outlet.) The point of bringing up the outlet strip is that one can have a properly functioning automatic on feature with any separate amplifier (well, with that outlet strip, any amplifier that draws, in combination with the receiver, no more than 15 amps), if one wishes.

 

[Pyrrho]

I concur. I have yet to see a powered sub made with a cabinet that is susceptible to vibration.

The next time you use your subwoofer on something with loud, deep bass, I suggest placing your hand on top of the cabinet and observe whether or not you feel anything, and compare that with how it feels when the subwoofer is off. If you feel something, you can be sure that the built in amplifier "feels" it too.

 

[Pyrrho]

Too me, buying a sub without a built in amp would be like buying a Ferrari 430 without the engine. Sure, you could shoehorn a small block chevy in there, but hell, whats wrong with the 32 valve engine designed for it?

Non Powered subs are so '80's .

I think you might be misunderstanding the point. I am talking about using a separate amplifier with the subwoofer rather than a subwoofer with a built in amplifier. Typically, this means one would use the subwoofer line level output of a receiver to connect to a separate amplifier, which is connected to the subwoofer. Doing this is, in my opinion, better than using a subwoofer with a built in amplifier.

As for the size of the amplifier, with a separate one as I suggest, one may get one as powerful as one wishes, just like one may select whatever amplification one wants with one's main speakers. (Obviously, some choices would be foolish, like an amplifier rated for nothing less than 8 ohms used with a 2 ohm speaker, but there are no more issues with selecting an amplifier for an unpowered subwoofer than with selecting an amplifier for one's main speakers.)

See, for example:

http://www.svsound.com/products-sub-cyl-csultra1.cfm

 

[sst]

One thing that is not mentioned is quality of amplification. An external amp e.g. a powerful receiver or Class AB amp provides "higher quality/distortion free" power with fast delivery as needed. So if you are listening to music , a subwoofer powered by class AB amp will sound better than a powered subwoofer with a class D amp ( Class D amp provides low quality power or higher distortion at a slower delivery rate)

 

[Warpdrv]

Also lets not forget, that there are not alot of Plate Amps avail as a really high power or high quality, therefore.... Many people don't have the option of using a built in amp when DIY....

 

[Buckeye_Nut]

The next time you use your subwoofer on something with loud, deep bass, I suggest placing your hand on top of the cabinet and observe whether or not you feel anything, and compare that with how it feels when the subwoofer is off.

I assure you that my subwoofer is more vibration free than the entire room and it's contents during movies.

If you place your hand on your subwoofer during a loud action sequence, and if you feel more vibration by touching your sub than you can detect by placing your hand on room walls (or contents) at any location within the room....... then it's time you treat yourself to a subwoofer upgrade

 

[Pyrrho]

The next time you use your subwoofer on something with loud, deep bass, I suggest placing your hand on top of the cabinet and observe whether or not you feel anything, and compare that with how it feels when the subwoofer is off.

I assure you that my subwoofer is more vibration free than the entire room and it's contents during movies.

If you place your hand on your subwoofer during a loud action sequence, and if you feel more vibration by touching your sub than you can detect by placing your hand on room walls (or contents) at any location within the room....... then it's time you treat yourself to a subwoofer upgrade

What you are saying does not make any sense. If a subwoofer is capable of moving everything in the room, surely it is capable of moving itself.

I get the distinct impression that you have not tried what I suggested. I can feel the vibrations from EVERY subwoofer that I have placed my hand on, when it is producing deep bass. I guess you imagine that I need to upgrade my SVS CS-Ultras to something better....