Sub-Woofer Connection Question

[Dougal]

I'm on a learning curve here, so please bear with me;-)

 

Current setup is:  Optical cable from PC to 'SMSL SA-50 Plus' amp/dac.  Phono/RCA from there to Q-Accoustics speakers.

 

I want to add a sub but the only outputs on the amp are the four phono outs to speakers.

 

Can you guys please advise how to hook up a sub please?  I'm assuming it must be an 'active' sub (not yet purchased)

 

Thanks

[jcn3]

according to the pic that i found of the sa-50 plus, there is no rca/phono line level out on this unit -- only connections for speakers.  you should be using speaker cables to the speakers.

 

there are subs that can accept speaker level signals.  the setup in this situation is  sa-50 >>(speaker wire)>> sub >>(speaker wire)>> speakers

 

[Dougal]

4 hours ago, jcn3 said:

according to the pic that i found of the sa-50 plus, there is no rca/phono line level out on this unit -- only connections for speakers.  you should be using speaker cables to the speakers.

 

there are subs that can accept speaker level signals.  the setup in this situation is  sa-50 >>(speaker wire)>> sub >>(speaker wire)>> speakers

 

Of course yes.  Quite why I called them phono/rca is beyond me. The outputs are just using speaker wires with banana plugs.

 

Is there a formula of any sort to establish what power sub is appropriate?

The amp is rated at 50w per channel and the Q-Acoustic speakers are are rated the same at 50w rms and 6 ohms.

[Guidof]

REL make subs that are designed to be connected from the speaker level outputs of an amp.

[mansr]

4 hours ago, Guidof said:

REL make subs that are designed to be connected from the speaker level outputs of an amp.

I have one of those. Works as advertised. Affordable too.

[wgscott]

6 hours ago, mansr said:

I have one of those. Works as advertised. Affordable too.

 

They are great when they don't fail (as the first one did) or ignite in your living room (as the second one did).  But I got #3 at half price.  Somehow I take comfort in the fact that you have one too -- I was pheeling quite the audiophool.

 

As for the OP, there are a bunch of brands that have speaker-level inputs.  Velodyne for example usually have them.  

[Dougal]

Is this the type of input/output I need?

[mansr]

4 minutes ago, Dougal said:

Is this the type of input/output I need?

That should work.

[wgscott]

23 minutes ago, Dougal said:

Is this the type of input/output I need?

 

Yes, and you also have two choices:

 

(1) use the input and output, which will allow you to use the crossover within the sub, thereby sending the low frequency to the sub and the higher frequency to the speakers.  This is the preferred method with bookshelf speakers and others that don't have a good low frequency response.

 

(2) use only the input, in parallel with your speakers.  This will work with full-range speakers, and allows the low frequency signal to be reproduced by the speakers and the sub.  You really have to pay attention to sub placement and relative phase, but it could potentially sound better.

[Dougal]

Many thanks for the help guys. I appreciate it.

[Dougal]

Are these subs likely to be as poor as the prices suggest?  They're about all I can afford for now;-(

 

http://www.ebay.co.uk/itm/Fenton-10-Active-Powered-Hi-Fi-Subwoofer-Home-Cinema-Bass-Bin-Speaker-200W/152703454727?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

 

http://www.ebay.co.uk/itm/10-HI-FI-HOME-CINEMA-ACTIVE-SUBWOOFER-SOUND-SYSTEM-150W-RMS-FRONTFIRE-BASS-SUB/201126494880?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

 

http://www.ebay.co.uk/itm/200-WATT-ACTIVE-SUBWOOFER-8-BLACK-HOME-HIFI-CINEMA-BASS-SPEAKER-POWERED-SUB/152059311188?hash=item236770f454:g:REgAAOSw44BYf8LR

[left channel]

One does tend to get what one pays for. But if you tell us about your speakers, we might be able to better assist you in selecting a sub.

[Dougal]

16 minutes ago, left channel said:

One does tend to get what one pays for. But if you tell us about your speakers, we might be able to better assist you in selecting a sub.

Small Q-Accoustics 3010 speakers

https://www.qacoustics.co.uk/q-acoustics-3010-compact-bookshelf-speakers-pair.html

 

apologies, I thought i'd listed these in 1st post.

[left channel]

Have you considered a subwoofer from the same manufacturer? They claim "the 3070S subwoofer perfectly complements all Q Acoustics 3000 and 2000i series stereo and center channel speakers".

 

I see four good reviews on Amazon UK, which shows it in stock at four UK dealers starting at a lower price than I see in the States. The only review with less than five stars anywhere is by an American who said it is a good match for music and not home theater speakers, which is true...

 

Apparently he still doesn't know he's embarrassed himself. We're doing a lot of that these days.

[left channel]

.

[Dougal]

16 minutes ago, left channel said:

Have you considered a subwoofer from the same manufacturer? They claim "the 3070S subwoofer perfectly complements all Q Acoustics 3000 and 2000i series stereo and center channel speakers".

 

I see four good reviews on Amazon UK, which shows it in stock at four UK dealers starting at a lower price than I see in the States. The only review with less than five stars anywhere is by an American who said it is a good match for music and not home theater speakers, which is true...

 

Apparently he still doesn't know he's embarrassed himself. We're doing a lot of that these days.

I have indeed, but at almost 3 times what i can afford right now, sadly its out of the question:-(

[left channel]

Might be worth waiting a few paychecks. The right sub can make a big difference in the right system. Some may unbalance it.

 

For a smaller slice of wages, would you consider a different amp with a sub out jack, to give yourself more options?

http://www.ebay.co.uk/itm/SMSL-A2-TDA7492-2-x-40W-Stereo-Amplifier-with-Sub-Out/322222227602

 

I have that one. You can always put your current amp back on eBay when you're done with it.

 

 

[Dougal]

21 hours ago, left channel said:

Might be worth waiting a few paychecks. The right sub can make a big difference in the right system. Some may unbalance it.

 

For a smaller slice of wages, would you consider a different amp with a sub out jack, to give yourself more options?

http://www.ebay.co.uk/itm/SMSL-A2-TDA7492-2-x-40W-Stereo-Amplifier-with-Sub-Out/322222227602

 

I have that one. You can always put your current amp back on eBay when you're done with it.

 

 

Looks like that amp doesn't have the optical input like mine. Do you think I'd miss it with my setup?  My music is supplied to the amp/dac via the optical output of my PC.

[left channel]

Yes, sorry, I'm probably opening up a whole new "can of worms" for you with USB input. Perhaps you should just experiment with one or two of those Chinese subwoofers. You can always put them back on eBay too.