Speaker Level Subwoofer Input: 1 sub per speaker?

Niber

Standard Member
Hi,
I recently bought a new setup, but found that the subwoofer I bought is a little underpowered. So I was thinking about buying a 2nd identical sub, but then I realized my amp only has 1 subwoofer output.
To make things worse, my amp doesn't have a volume-boost for the sub signal, so I can't use a Y-cable to branch the 1 output into 2 subs either (i suspect the signal will be too weak)

However, if I use the "speaker level input" on the subwoofer, then maybe I could connect one sub to left, and the other sub to right.

Does that sound like a good idea?

Gear:
*2x KEF Q950
*Cambridge ARX100
*1x SVS SB1000 subwoofer
Room: 40sq meters
 

gava

Well-known Member
Hmm, I'm slightly surprised, the SB1000 is not a particularly anaemic.

One advantage of having multiple subs is that you can reduce nulls in the listening position. I suspect this is actually your main problem at the moment, not that your sub is underpowered, but that it's in the wrong place for your main listening position, or you have a funny shaped room.

How did you go about positioning the sub?
 

noiseboy72

Distinguished Member
You can use a Y signal. There will be no drop in level, as the sub input will be high impedance and the sub output from the line output significantly lower impedance. This means the signal will not lose any level when split in this way.

You can just attach them to your mains using the speaker connection, but you will get less control of them that way.
 

Niber

Standard Member
You can use a Y signal. There will be no drop in level, as the sub input will be high impedance and the sub output from the line output significantly lower impedance. This means the signal will not lose any level when split in this way.

You can just attach them to your mains using the speaker connection, but you will get less control of them that way.
Interesting. In my previous setup this wasn't the case, I bought a Y shaped subwoofer cable and it lowered the subwoofer volume by about half. That was a budget surround receiver and some used Wharfedale SW150's.
Are you saying that this is because SVS subs are using a better method or something?

What less control are you refering to? I know that many receivers have great control of things like bass management, timing etc, but unfortunately Cambridge AXR100 has literally no settings about their sub-out.
 

Niber

Standard Member
Hmm, I'm slightly surprised, the SB1000 is not a particularly anaemic.

One advantage of having multiple subs is that you can reduce nulls in the listening position. I suspect this is actually your main problem at the moment, not that your sub is underpowered, but that it's in the wrong place for your main listening position, or you have a funny shaped room.

How did you go about positioning the sub?
Absolutely I can probably squeeze out more effect by experimenting with phasing and positioning, but realistically I don't think we're talking about doubling the effect. And in the case of my SB1000 it's ramped up to 100% max.

To use a metaphore, imagine if I complained that my car drove too slowly, even tho I had pedal to the metal all the time. If someone said there's a way to make it 5% faster, another might say that "the fact that you're always pedal to the metal is a sign that you need much more than just a tweak". Not sure if that logic applies to subs tho, it might be that having it 100% isn't a sign that it's struggling
 

noiseboy72

Distinguished Member
Interesting. In my previous setup this wasn't the case, I bought a Y shaped subwoofer cable and it lowered the subwoofer volume by about half. That was a budget surround receiver and some used Wharfedale SW150's.
Are you saying that this is because SVS subs are using a better method or something?

What less control are you refering to? I know that many receivers have great control of things like bass management, timing etc, but unfortunately Cambridge AXR100 has literally no settings about their sub-out.
If the level was dropping, there was a fault somewhere. Balanced 600 Ohm systems will only lose 3db - and that's with matching impedances. Unbalanced system are high impedance and there really shouldn't be any drop at all.

If you amp doesn't have any control, then high level speaker connection won't make any difference. I was referring to AVRs, which have bass control built in, so the crossover frequency and other bass management - such as defining the speaker "size" and in some cases EQ can be changed.
 

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