# Sub Woofer



## NairbD (Nov 12, 2011)

I just got my first sub. Polk Audio 10", 100 W


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## phreak (Aug 16, 2010)

Have you had a listen yet? Are you happy with it?


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## NairbD (Nov 12, 2011)

Hi Phreak. Yes, I've listened to it and am happy so far. Just heard about "Shack" so thought I see what help I can get with setting it up properly. I see you are from Red Deer. I lived in Calgary for a few years back in the day. Would have liked to get a Paradigm sub. but the Polk Audios were just under $100.00 US not bad for a powered sub. I just have to adjust the x-over and tone down the Volume...I like bass as much as the next guy but Boominess I hate! I sure miss Canada.:wave:


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## phreak (Aug 16, 2010)

What receiver and speakers are you running? The setup for your sub is influenced (maybe dictated?) by the rest of your equipment


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## NairbD (Nov 12, 2011)

Hi again Phreak. I have an Onkyo 807 my main L&R spkrs are JBL's from their Pro-line an 8" Woofer and 075 Tweeters (from about 1970) The Cabs are DIY bass reflex I made out of Walnut vineere plywood (3/4") MDF was not available back then... they are bookshelf size. My set-up is basically 5.1 with some decent Radio-Shack spkrs in the back. havent decided on what to use as a center channel yet. I tried to bi-amp the main spkrs but I didn't like the x-over freq that Onkyo provided. I hear they had a lot of complaints about it and a firmware fix was available for it by the time I was able to download the fix (I did not have highspeed internet at the time I got the receiver and now that I do... this fix is no longer on the website. So I'm going to try to come up with a passive x-over to correct the problem. I'm looking forward to downloading the spectrum analyzer that I can download from This site to help me with that as well as the sub.

Sure sounds like you've got quite a system.... I'm Jealous! :T


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## phreak (Aug 16, 2010)

I don't really see the point of bi-amping from a receiver and using a passive crossover downstream. This means you are amplifying the signal on extra channels, only to dissipate it back into heat again. A large extra load on the receiver with dubious benefit. Bi-amping may work well if the crossover is applied prior to amp, but even then is often not audibly better unless listening level is too high for the receiver on a single pair of channels. But hey, no harm in trying it out to see if it appeals to you. For setting up the crossover on the sub, just turn it up to max setting and let the receiver handle the LPF through Audessey. Don't expect the sub to grab you by the shoulders and give you a shake, it's rated -3dB point is 40hz. It should assist your mains nicely though.


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## NairbD (Nov 12, 2011)

Thanks Phreak. Your advise makes sense to me. think I'll "goof" with it and see what I can come up with but it certainly isn't worth spending any money on. I have enough resistors and caps to play with it and as you probably know, a hobby is just that... a hobby, and I'm retired now so what the . The one time I tried to bi-amp it, I didn't like it at all but you reminded me that I never ran that set-up thru Audessey so I'll see how well that handles it. Polk Audio also recommends setting the x-over for the sub to Max, (That is fully counter- clockwise=80Hz while fully clockwise is 180 Hz. just by sound I've got both the x-over and volume set to 11 O'Clock and in phase. I didn't like the way that Audessey had set that up... too boomy for me but I think that setting is best for LFE but I really use it to enhance my mains and extend the low frequencies for music. I'm just starting to think about the Video end of my sound system... eventually that may become quite important to me but since I can't afford a HDTV right now and I am basically a Music guy that is where my focus is now. I'll let you know what I come up with.

Thanks :sn:


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## phreak (Aug 16, 2010)

You are on the right track with the setup, I'm sure you will get everything tuned to your liking. Set crossover at 180 if using Audessey. If not, you will probably want to be around 80-120hz. Do you run your mains as large (full range) or small (Audessey sends bass to sub)?


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## deakon (Nov 16, 2011)

that should be a good and faithfull unit.


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## NairbD (Nov 12, 2011)

I currently have my main speakers set up as full range but if setting them up as "small" I will try that first I guess that should send most of the bottom end to the sub. My only concern is that if it sends anything above about 150 Hz to the sub that it may have too much too much directional information comming from the sub and I do not want to call attention to it's location aurally. But I will try it and see.... thanks Phreak for the advise You have already been quite helpful and have given me a lot to think about.


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## phreak (Aug 16, 2010)

No worries, the sub won't see 180 hz. The receiver will direct all LFE to the sub (which is 120 hz max) and the crossover setting in the onkyo will limit the upper bass going to the sub at your setpoint. THX recommends running 80hz crossover on all speakers and subs, but you may find other settings that sound better for your equipment, your room, and most importantly your ears. 80hz is a failsafe easy setting if you have decent and well matched equipment. With a underpowered sub and much better mains, crossover may be set lower or mains run full range. With a monster sub and tin can speakers, crossover may need to go higher. The only time to consider a crossover higher than 120 hz is if your speakers are the 3 inch squawk boxes that come with cheap HTIB systems (not very popular in the Shack). When using Audyssey the crossover on the sub should be set to highest frequency or bypass so that you aren't compounding the filters. If set at 80hz on the receiver and 80 hz on the sub, instead of a smooth roll-off the switch from sub to mains will be like a brick wall, which would be noticeable and objectionable. Ideally, you should not be able to hear where the sub stops and mains start.


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## NairbD (Nov 12, 2011)

Thanks again Phreak! I'll experiment with it. Can I use the Audessy mike with the REW program I downloaded from this site?


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## phreak (Aug 16, 2010)

I don't think so. For REW to be useful it needs a cal file to reference the mic output to room volume. Best to ask questions in the REW forum, they have some guys there with a vast amount of knowledge. As far as I know, the cheapest way to start is a laptop soundcard and RS SPL meter, but this has limitations. Do some reading at the REW forum, you will be reaching for Tylenol right away.


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## Mike P. (Apr 6, 2007)

Thread moved to Home Audio Subwoofers.


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