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Getting subwoofers for the first time

Robert

Tapehead
On Monday I will take delivery of a pair of subs, the newly revamped SVS SB1000 Pro.

https://www.svsound.com/products/sb-1000-pro-subwoofer

Apparently multi sub is the way to go if you want best performance and avoid the issue of having that small sweet spot of perfection when it comes to seating.

In all my years in this hobby I've never run subs, and I suspect like many audiophiles it feels like you've failed when you just can't get a simple system with a stereo pair of 'speakers in a typical room to give great, even bass. But I'm giving in. I've done it with panel 'speakers but never got close to nirvana with boxes.

Part of this is being driven by me being absolutely in love with Kef LS50s. These things do almost everything I want and more used in a near-field arrangement pulled well clear of boundaries, up nice and high.
They nail vocals like few 'speakers I've encountered and the ability to disappear and just leave a performance in front of me is very addictive. Of course they are a very small box and lack the heft and muscularity of something able to go low with grip. The Kefs do pretty well - very well in fact for a small ported cabinet (and what a cabinet!) but I'd like more.

Needless to say, reading and research has begun in earnest and that's the reason for my post.
How do run your subs, how do you position them for best results and have you found any good articles or videos on multi-sub setup?

Not asking you to Google for me :) - I can do that, just looking to explore the pfm collective knowledge :)
 
I use an old REL Stadium with my Shahinians. I use the old method REL always recommended for setting them up. Basically:

Play some bass heavy music and turn the xo point up and the volume (adjustment isn’t needed yet).

Then, move the sub around (a friend helps) until the output is loudest at the listening position.

Once in that position, which may well be limited by space considerations but, even then, small adjustments of a few degrees or centimetres can make significant differences, adjust the phase until output at the listening position is maximised.

When these steps are complete, leave the volume highish and adjust the xo point. Turn it as low as it will go and gently bring it up to the point you hear audible duplication of what the speakers are doing. Back off a little.

Then adjust the volume. It’ll likely need to be very low but experiment over several days in small steps and enjoy. Mine works a treat.

Of course, you can just use DSP...
 
Thanks K
The SVS subs have some DSP built in, so would a miniDSP be needed?

Assuming Keith is referring to high-passing the LS50 with the miniDSP.

That's an option for later - it would mean changing my integrated amp for a pre and power set up but I plan to see where just using the quite comprehensive DSP within the subs gets me first.
The LS50 can be run closed box and in that mode they start rolling away at around 100Hz. Ideally you want electrical high pass.

Thanks for the replies - keep them coming :)
 
On Monday I will take delivery of a pair of subs, the newly revamped SVS SB1000 Pro.

https://www.svsound.com/products/sb-1000-pro-subwoofer

Apparently multi sub is the way to go if you want best performance and avoid the issue of having that small sweet spot of perfection when it comes to seating.

In all my years in this hobby I've never run subs, and I suspect like many audiophiles it feels like you've failed when you just can't get a simple system with a stereo pair of 'speakers in a typical room to give great, even bass. But I'm giving in. I've done it with panel 'speakers but never got close to nirvana with boxes.

Part of this is being driven by me being absolutely in love with Kef LS50s. These things do almost everything I want and more used in a near-field arrangement pulled well clear of boundaries, up nice and high.
They nail vocals like few 'speakers I've encountered and the ability to disappear and just leave a performance in front of me is very addictive. Of course they are a very small box and lack the heft and muscularity of something able to go low with grip. The Kefs do pretty well - very well in fact for a small ported cabinet (and what a cabinet!) but I'd like more.

Needless to say, reading and research has begun in earnest and that's the reason for my post.
How do run your subs, how do you position them for best results and have you found any good articles or videos on multi-sub setup?

Not asking you to Google for me :) - I can do that, just looking to explore the pfm collective knowledge :)

Enjoy the journey!

I’ve not set up duals before but it’s certainly on the wish list. I like the REL way but I believe that works on the assumption that you’ve got plenty of space to move the sub around the room. This is not the case for me now, so I have to use dsp. I’ve got some room correction, subtle, in my Meridian processor that I use. minidsp also ideal I’d say and is not too expensive.

if I were setting duals or more I’d be using REW and re watching this video quite a few times! It assumes you have the minidsp.

SVS are pretty helpful so worth emailing the support team in the US.

 
Assuming Keith is referring to high-passing the LS50 with the miniDSP.

That's an option for later - it would mean changing my integrated amp for a pre and power set up but I plan to see where just using the quite comprehensive DSP within the subs gets me first.
The LS50 can be run closed box and in that mode they start rolling away at around 100Hz. Ideally you want electrical high pass.

Thanks for the replies - keep them coming :)

Earl Geddes' work on multi-sub setup is widely respected - but it usually involves three or four subs, rather than a pair. Worth reading anyway, maybe. Google will give you loads on it.

Another thought: if you do, in the future, want to run separate pre and power amps, and want to high-pass the mains, you could also try a simple passive line-level network, rather than running your mains through an extra layer of processing. See: http://www.troelsgravesen.dk/High-Pass-Filter.htm
 
That's an interesting pairing.

Not sure what the rest of the system is but i'd expect a reasonably high crossover to take some load from the KEFs. Maybe 85? you can go higher with stereo subs.

I use paired subs and they have ended up in the front corners a bit closer to listening position than the mains, about 6" closer.

I guess if the KEFs need a little air around them that could be a pain. i'd agree with irb.

Spend plenty of time setting up
 
Thanks all for the info and links- much appreciated.

One of the subs just arrived so I'll be able to make some initial measurements and tests. Prefer Arta to REW as you can load it into a tablet, plug Ina UMIK-1 and walk the room taking real times plots.

Have you looked at the Kef KC62? I’m looking to try one of these with my Metas.

I did look at the 62 initially as it's the natural choice for the LS50.
However it is expensive and for sure a lot of the cost has been allocated to getting good results from a very small box. For the price of one 62 I could buy a pair of 12"driver units from a reputable subwoofer company with full DSP. Larger for sure but I didn't fancy blowing £3K on a pair of 62s as an experiment.

Worst case here is that if I don't like them on music I'll set them to play at the very lowest frequencies, well below where the Kef's are rolled off and use them to add some shake rattle and thump to movies.
 
Thanks all for the info and links- much appreciated.

One of the subs just arrived arrived so I'll be able to make some initial measurements and tests. Prefer Arta to REW as you can load it into a tablet, plug Ina UMIK-1 and walk the room taking real times plots.
Go old skool, stick the Sub in the sweet spot seating position, play some bassy tunes and crawl the room listening for the best locations.

Close the door or the family will think you’re nuts or looking for loose change :)
 
Before DSP, common advice was to "locate the sub where it is the loudest". I'm curious about the logic of this advice. A sub is going to drive room modes and nulls differently at different locations relative to a particular seating position.


Placing the sub hard against the front wall, for example, is going to maximise excitement of the front-to-rear wall axial mode and will therefore sound loudest at this frequency (typically around 40Hz in an average UK room), but not necessarily the loudest at frequencies higher than this.

Before the advent of room measurement I'd have thought better advice would have been to play a recording of a bass guitarist 'walking' up the fretboard and position the sub where all of the notes sound the most equal in volume with no deep 'holes'.

RTAs make this job much easier, but I suspect best results will still be achieved with DSP so that phase/timing is optimised.
 
Seconding the choice of more than one
SVS SB1000 Pro and about the suggestion to look into Earl Geddes multi sub approach (who in few words advocates the use of three subs) and would look into the Swarm multi subwoofer array too.
As for the main speakers, maybe that's just me but I would not use any dsp on those.
 
Go old skool, stick the Sub in the sweet spot seating position, play some bassy tunes and crawl the room listening for the best locations.

Close the door or the family will think you’re nuts or looking for loose change :)

Haha luckily just me here so I can go completely nuts all weekend :)
 
just unboxed one and here it is beneath an LS50 for scale.
Interestingly it fits perfectly inside those Ikea record storage units and I have those running along the entire back wall of the room. So if one sub ends up along the back wall it sit in one of those near the floor.

Very solid thing and looks superbly built. Definitely good material value for £630.

PXL_20210424_181313647 by Rob Holt, on Flickr
 
Plug the ports of the LS50s, measure the response. You should get a 2nd order high pass with a corner frequency of about 80Hz. Use this as your crossover frequency.
Set the subs for 4th order LR rolloff at 80Hz.
Arrange for a 2nd order filter for the LS50s at 80Hz, this will add to the 2nd order rolloff of the speakers themselves and provide excellent integration with the subs.
Position the subs near to the LS50s.

You will benefit from:
1) Reduced distortion because the LS50 doesn't have to do large excursions (at LF)
2) Reduced group delay due to there being no port output
as well as the obvious 3) extended bass response and increaed loudness capability
 
I’d have a look at the Neumann KH750 DSP subwoofer. It has inbuilt DSP, and associated alignment software and app, and measurement microphone. Also supports multiple sub configurations. Neumann used to make anti-subs too - ie active bass absorbers, but they stopped. The 750s are more money than the subs the op is getting, but he wouldn’t need extra DSP boxes. And Neumann are very professional, engineering led company with measurements and graphs in abundance. Even if you don’t fancy the speaker, there’s lots of interesting stuff in the set up documentation that might help.
https://en-de.neumann.com/kh-750-dsp
 
Thank you Robert for documenting your sub experience. Like you say it seems like sacrilege in some audiophile circles to use a sub and I've never gone there, will be interesting to hear what you think it adds / takes away from the music when you get it dialed in.
 
My experience of subs: unbox them, plug them in, turn them on, over the next few months alter the cutoff, phase and level, gradually reducing the impact of each, keep turning them down until you can’t hear the slowness and lack of coherence, realise they are now actually off, box them back up and sell them.
 


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