Question on subwoofers

[Jim H B]

Hi, I'm still fairly new to subwoofers, but do find that they can fill out the sound of my 2 channel audio setups nicely.

With the typical powered subwoofer, there are two inputs - a set of one or two rca inputs (LFE or line level), and inputs using speaker wire.

I usually use old school two channel stereo receivers, with no dedicated subwoofer output, but with outputs for two sets of speakers.

I assume I would use one set of speaker outputs for the two stereo speakers, and use the other speaker outputs to run speaker wire to the subwoofer - and make sure to set my receiver to output to both speaker outputs ( a + b).

My question - when using this type of input to the sub, does the amplifier in the sub still play a role, ie, does it amplify the speaker wire input?

Also - I know I can hook up my stereo speakers to the speaker wire outs on the sub, but for some reason, I'm hesitant to do that - I like the sound of my receiver, why not hook my speakers up to it? But I'm open to other reasoning, or experience in this area.

Thanks for any input.

 

[the skipper]

Ya kinda lost me here but I';; try to explain a speaker level subwoofer hookup/

Obviously, you connect your amp's speaker outputs to the sub's speaker inputs. You knew that.

Now, about your mains, you have several options:

The simplest is to simply keep then connected to your amp. No harm will come to your amp.
.
Some subwoofers do offer speaker outputs. All these do is take the signal from your main amp and pass them out to your mains. These are simply a convenience and don't affect the sound

But, some, not all, subwoofers will strip out the lows from your mains because the sub will be handling that. This might afford a cleaner sound since your mains won't be trying to reproduce the very low signals.

 

[orsen]

I usually use old school two channel stereo receivers, with no dedicated subwoofer output, but with outputs for two sets of speakers.

I assume I would use one set of speaker outputs for the two stereo speakers, and use the other speaker outputs to run speaker wire to the subwoofer - and make sure to set my receiver to output to both speaker outputs ( a + b).

yes and yes
also your reciever will not "see" a load caused by this method

Also - I know I can hook up my stereo speakers to the speaker wire outs on the sub, but for some reason, I'm hesitant to do that - I like the sound of my receiver, why not hook my speakers up to it? But I'm open to other reasoning, or experience in this area.

some subwoofers would relieve your main speakers of bass duty this way, from my experience, most do not and your mains will still be full range

 

[orsen]

the skipper beat me to it

 

[Jim H B]

Thanks guys, I appreciate the info.

I suppose one benefit of using the speaker wire outs on the sub to run your main speakers would be a clean cut off. For example, you would know that the mains are getting everything above 100hz, the sub getting everything below 100hz (assuming the sub doesn't pass the full range to your mains). No overlap.

 

[the skipper]

That depends on the subwoofer. Remember, not all subs roll off the lows. Most are just a straight pass through.

 

[Jim H B]

That depends on the subwoofer. Remember, not all subs roll off the lows. Most are just a straight pass through.

Got it, thanks. And it's funny how the manuals or the specs won't say anything about that. That's why we have ears!

 

[Jim H B]

Here's an excerpt from the manual for my Klipsch subwoofer manual


This is a little confusing to me - it seems to say that if I hook up my main speakers to the speaker wire outs on this sub, they will only be fed 120hz and above, regardless of where the Low Pass Control is set. Is that how you interpret it? So if you set the low pass control to 100hz, neither the sub, nor the mains would produce from 100hz to 120hz?

 

[spark1]

Got it, thanks. And it's funny how the manuals or the specs won't say anything about that. That's why we have ears!

If the sub has a high pass crossover for the main speakers, the manual will say so.

Otherwise, both the subs and the mains will receive a full range signal.

Just about all powered subs have an adjustable low pass filter, so as to set the point at which the sub rolls off (around the points where the mains start dropping off).

But yes, use your ears to get the best blend and avoid excessive low end.

 

[the skipper]

You have more options when you use the line level inputs. Then you can adjust the low pass frequency and level and these will affect the subwoofer only..These won't affect the speaker level outputs because you won't be using them.

These options are not available when using the speaker level inputs and outputs. You are stuck with what they offer. If you don't want the lows filtered out, connect your mains directly to the amp.

 

[spark1]

Here's an excerpt from the manual for my Klipsch subwoofer manual
View attachment 1407033

This is a little confusing to me - it seems to say that if I hook up my main speakers to the speaker wire outs on this sub, they will only be fed 120hz and above, regardless of where the Low Pass Control is set. Is that how you interpret it? So if you set the low pass control to 100hz, neither the sub, nor the mains would produce from 100hz to 120hz?

The adjustable low pass crossover affects only the subwoofer, regardless of how the sub is connected.

If the mains are connected to the speaker outs on the sub, the fixed high pass filter will block lows to the mains, starting at 120Hz. The roll-off is gradual, not a brick wall. The drop-off curve is defined by the design of the high pass filter.

The alternative is to connect mains directly to your amp/receiver, in which case both the sub and the mains are getting a full range signal...which of course the sub's low pass filter blocks all but the lower frequencies. The low pass filter affects only the subwoofer...not the mains.

The specific roll-off point (crossover point) is defined by the crossover point adjustment control.

 

[Grenadeslio]

If you look at the part you underlined it states "If this is provided by your subwoofer", I see four models mentioned, are you sure your model provides this feature?

If so the line level of 80hz is more preferable unless your mains are Minimus 7's or something along those lines.

I downloaded the manual for all three models and from what I could find online only the SW8 & SW10 have this feature.

 

[Jim H B]

The adjustable low pass crossover affects only the subwoofer, regardless of how the sub is connected.

If the mains are connected to the speaker outs on the sub, the fixed high pass filter will block lows to the mains, starting at 120Hz. The roll-off is gradual, not a brick wall. The drop-off curve is defined by the design of the high pass filter.

The alternative is to connect mains directly to your amp/receiver, in which case both the sub and the mains are getting a full range signal...which of course the sub's low pass filter blocks all but the lower frequencies. The low pass filter affects only the subwoofer...not the mains.

The specific roll-off point (crossover point) is defined by the crossover point adjustment control.

Very useful, thanks.

 

[Jim H B]

If you look at the part you underlined it states "If this is provided by your subwoofer", I see four models mentioned, are you sure your model provides this feature?

If so the line level of 80hz is more preferable unless your mains are Minimus 7's or something along those lines.

I downloaded the manual for all three models and from what I could find online only the SW8 & SW10 have this feature.

View attachment 1407115
View attachment 1407116

I took "provided by your subwoofer" to mean that your mains are hooked up to the speaker outs on the subwoofer - but you may be right - in that case I wouldn't know, because it doesn't say what models have that feature. I have the 10, which has a different amp than the 12 and the 15 models, but still has adjustable low pass filter.

My main problem with this sub is that it seems like it's either too soft or too loud, hard to get it to blend in well. I've been connecting my mains directly to the receiver, so they are getting full range. Maybe connecting them to the subwoofer speaker outs would help with the blending. 120hs cut off just seems too high though, but you never know until you mess around with it. And messing around is the fun part!

 

[spark1]

I took "provided by your subwoofer" to mean that your mains are hooked up to the speaker outs on the subwoofer - but you may be right - in that case I wouldn't know, because it doesn't say what models have that feature. I have the 10, which has a different amp than the 12 and the 15 models, but still has adjustable low pass filter.

My main problem with this sub is that it seems like it's either too soft or too loud, hard to get it to blend in well. I've been connecting my mains directly to the receiver, so they are getting full range. Maybe connecting them to the subwoofer speaker outs would help with the blending. 120hs cut off just seems too high though, but you never know until you mess around with it. And messing around is the fun part!

Not sure what I "may be right about"?

If your su has a high pass filter, it will only be usable if you connect your mains to the subwoofer's speaker outputs.

It appears that the high pass filter is at 120Hz if you are feeding the sub with speaker level output, and 80Hz if with line level output.

If true, you may find that blending the sub and mains is easier with line level input tothe sub.

 

[the skipper]

You may be overthinking this. What, exactly, are your mains?

I run my mains full range and adjust the sub so it starts cutting in where the mains fall off. It takes a bit of fiddling with the crossover and level controls but it works well.

The end result is that one really doesn't notice the sub until I turn it off. Then, the absence of the deep bass is quite noticeable.

Unless you consistently crank the bass control, it works well,

 

[spark1]

Not sure what I "may be right about"?

If your sub has a high pass filter, it will only be usable if you connect your mains to the subwoofer's speaker outputs.

It appears that the high pass filter is at 120Hz if you are feeding the sub with speaker level output, and 80Hz if with line level output.

If true, you may find that blending the sub and mains is easier with line level input tothe sub.

Ok, I looked up the manual for the SWII series.

At least wih that series, your options are:

• Connect mains and sub to your receiver via speaker terminals. No high pass filter in this scenario.
• Connect sub from receiver speaker terminals, and connect mains to speaker outs of the sub. Signal to mains is high-pass filtered at 120Hz.
• Connect sub to pre-out of receiver (pre out from receiver to line in of sub). Connect line out from sub to power amp in of the receiver. Connect mains to speaker terminals of the receiver. Signal from the receiver's pre out is high-pass filtered at 80Hz by the sub. This filtered signal is fed back to the power amp secton of the receiver, so any speakers connected to the receiver are high pass filtered. Note that this assumes the pre and power sections of the receiver are separable.
• Connect sub with line level output. If mains are connected to the speaker outs of the sub, they will be high pass filtered at 120Hz. If they are connected directly to the receiver, signal will be full range.

 

[Jim H B]

Ok, I looked up the manual for the SWII series.

At least wih that series, your options are:

• Connect mains and sub to your receiver via speaker terminals. No high pass filter in this scenario.
• Connect sub from receiver speaker terminals, and connect mains to speaker outs of the sub. Signal to mains is high-pass filtered at 120Hz.
• Connect sub to pre-out of receiver (pre out from receiver to line in of sub). Connect line out from sub to power amp in of the receiver. Connect mains to speaker terminals of the receiver. Signal from the receiver's pre out is high-pass filtered at 80Hz by the sub. This filtered signal is fed back to the power amp secton of the receiver, so any speakers connected to the receiver are high pass filtered. Note that this assumes the pre and power sections of the receiver are separable.
• Connect sub with line level output. If mains are connected to the speaker outs of the sub, they will be high pass filtered at 120Hz. If they are connected directly to the receiver, signal will be full range.

Excellent summary. Thanks so much guys. With the knowledge gained here, I reread the SWII manual, and it was much clearer. That's the power of AK.

I use a variety of speakers, from floorstanders to bookshelves. The ones I'm using currently, DLK Model 2's (great speakers) do pretty well down to around 70hz, thus my apprehension on the 120hz cross over. But I can sure see it for some Wharfldale Diamonds I have. I also have a variety of receivers, an integrated amp, a pre-amp & monoblock amp setup, and an a/v receiver with an actual LFE sub out. It looks like the Klipsch sub can handle all these scenarios.

I also got off on the wrong foot initially with the Klipsch sub - it had a hum, and then it was picking up radio interference (you could faintly hear police radios) - but both of these are actually addressed in the manual (the radio interference went away on its own when I moved).