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Need help understanding PC speakers subwoofer setup

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Overspeed

Limp Gawd
Joined
Feb 21, 2008
Messages
227
Hello everyone. Recently I bought myself a new set of computer speakers ($150 on sale from $500). The specific brand/model is Simple Audio Listen as seen here:

http://www.simpleaudio.com/all-products/bluetooth-speakers/simple-audio-listen

The set includes two speakers. It has an optional 'subwoofer out' RCA jack labelled as 'full dynamic range'. This is where my questions come into play.

While the speakers sound great as is, I wanted to add a subwoofer to complete the sound. I bought a Polk Audio PSW111. as seen here:

http://www.polkaudio.com/psw111/d/1177

I am not overly knowledgeable in regards to speaker and audio specs. I am trying to understand the various switches, inputs and knobs on the subwoofer. I'm also trying to get my head around the meaning of 'full dynamic range' and 'LFE'. The sub has two RCA inputs... L and R-LFE. It also has a phase switch with options of 0/180. Finally it has a knob labelled 'low-pass' which goes from 60/90/120/LFE. I need some help choosing which input and settings to use that best pair with the speaker's RCA jack labelled as 'full dynamic range'.

Can someone please help me understand these options and get a better understanding of the connectivity and settings I should be using? Please and thank you.

@Overspeed

P.S. I currently have it set up as follows, though i'm not sure if it's correct/optimal.

Input: R-LFE
Phase: 180
Low-pass: 90 (see below)
Sub Volume: 40%

I find that the audio sounded bad when the low-pass knob is set to LFE, almost as though it was trying to process frequencies it shouldn't be.
 
Full Dynamic range means it puts out the full frequency range from (probably) 20-20,000 Hz. As long as you have a subwoofer with an integrated low-pass filter (which you do), it's fine.
Subwoofers are mono rather than stereo since low frequencies are generally non-directional (you can't tell where they're coming from). Either of the inputs should work - internally the subwoofer just sums the two signals together to form a single signal, so you really only need one. If you only have one connection use the one marked LFE, but honestly either will work the same.
LFE means "Low Frequency Effects" which is what is the ".1" of a "5.1" system. It's really for things that are more meant to be felt than heard, or to add additional "oomph". If it's set to LFE, then it's expecting just a low frequency signal from the source and doesn't do any filtering, which is why you hear more through it than you should. This setting should only be used with a source that puts out a dedicated pre-filtered subwoofer signal, like a home theater receiver/amp. For full range signals you need some sort of filtering. The "low pass" switch determines what frequency the subwoofer goes up to. This should be matched to how low your other speakers go, but ideally it should be as low as possible. It becomes easier to tell where the sound comes from at higher frequencies, so for a single sub it's best to cross as low as possible, but not lower than your main speakers or you'll miss out on some of the sound range. Your system uses 3" speakers, which honestly don't go that low without extraordinary measures. Sorry, it's just physics. My guess is that 90 would be a bit low to cross the sub, 120 might be better, but you will have to listen to tell. Try some test tones (http://plasticity.szynalski.com/tone-generator.htm) and see if you have big drop offs or rises in sound level at frequencies between 60 and 150 Hz.
The phase switch just determines if the cone of the speaker goes forward with a positive input or backward. This is used to adjust for how or where it is placed in a room. Just adjust it to what sounds best. Also, just adjust the volume to what sounds best since there are way too many variables based on speakers, distance, room size and placement, room materials, etc. for anyone to diagnose over the internet.
 
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@Fenris_Ulf, that is helpful, thank you. I have set the cross to roughly 110. After this change I can hear more bass in guitar strings and other bassy instruments. I will try the tone generator test as suggested.

Edit: okay, after running the test, I can hear tones from 14599Hz to 20Hz, though I can 'feel' the tones below 20Hz. Anything below 80Hz sounds awful to be honest. The sub box shakes and makes an unnatural sound below 80Hz. Listening to 14599Hz for a long time started to make me feel a bit strange. Was a fun test though. Certain frequencies would start a resonating vibration on various items in the room, each responding to a certain frequency. Fun times.
 
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These aren't really worth the $500 asking price though and NCOs actually is selling these for about $100, even lower than the massdrop price. This was reviewed by Linus (whose pretty green on audio) and he didn't even think it sounded as good as other lifestyle products at this price range.
 
If your sub sounds bad under 80Hz something is wrong with your setup, likely it's being overdriven with an I/proper gain setting.

Sub input to white (non lfe port), phase at 0, crossover around 90. Though either rca should work. I usually Split the sub out With A rca Splitter. The main issue imho is that the speakers are passing a full rang range signal to the sub, without any filtering... why a mono full range output, I can't understand
 
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