Subwoofer hookup

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virtue

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Re: Subwoofer hookup
« Reply #20 on: 10 Jun 2014, 03:49 pm »
A capacitor forms a simple first-order cross-over.  So you're going to bleed at 6db/octave slope.  So there's some "nice" bleed.

Low frequency is lumpy.  You can fix it with digital cross-overs (Audissey), etc. or room treatment.

megabigeye

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Re: Subwoofer hookup
« Reply #21 on: 11 Jun 2014, 03:03 am »
Hoo boy!  You really lost me on that one!  Bleed?  6db/octave slope?  "Nice" bleed?  Sorry, I don't know what any of that means!

How does Audyssey work?  After a very cursory search, I just see it as being something built into some receivers?

At any rate, I think I'm going to try and leave well enough alone, at least for the time being.  I tend to get obsessed with the details sometimes and I have the feeling I may be making a mountain out of a molehill.  I'm going to try to ignore it for a little while and see if it "goes away."  I don't want to throw money at it just yet.

virtue

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Re: Subwoofer hookup
« Reply #22 on: 16 Jun 2014, 03:20 am »
The cut-over is not immediate.  If you cross at 70 hz, you'll get around 1/2 volume at 60hz and so on.  When you look at cross-over models you will see a summing of half-signals below the high pass and above the low pass.

virtue

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Re: Subwoofer hookup
« Reply #23 on: 14 Jul 2014, 12:01 am »
AFTER 2 DAYS, THE AMPLIFIER FRIED BECAUSE THE HIGH-LEVEL OUTPUTS GOT SHORTED SOMEHOW.  FAIR TO SAY THIS EXPERIMENT WAS A FAILURE.

I wanted to test the high-level subwoofer output myself and bought a Yamaha YST-SW315 from Amazon Warehouse (returns) for $236 delivered.  It's 10" paper cone, 250w.  Lots of power and pretty tight (although not Rhythmic).  It's not sunfire small but no bigger than I'd expected it to be for a down-firing design.  Footprint is slightly larger than my laser printer and fits fine under my desk.

http://usa.yamaha.com/products/audio-visual/speaker-systems/subwoofers/yst-sw315_black__u/?mode=model

The resistance between the high-level input channels (left input red & right input red) was 40k.  That's enough resistance so that virtually no current is crossing between channels, blowing up the amp.

AT SOME POINT DURING MY 2 DAY EXPERIMENT, THE SUB DID SEEM TO SHORT THE CHANNELS, KILLING THE AMP.  PERHAPS THIS OCCURRED DURING THE STAND-BY TRANSITION.  NOT SURE.

WITH THIS SUBWOOFER, CROSSING THE HIGH INPUTS IS A FAIL.

I'm letting the high-pass cross-over fade the low bass so the speakers don't see it.  Turning down the sub to 0% kills the low bass on the speakers, as it should.  I have the sub turned up 80% with the Stand-by enabled. 

Everything is coming through the amp as it should, including a very slight turn-on pop.  I don't hear any distortion although the audiophile in me "wonders."

The "high cut" allows crossing between 50hz - 150hz.  With these Tannoy 601s, 75hz or lower provides nice reinforcement that blends really well.   I'm losing some low-bass when I go all the way down to 50hz.  It fills in all the way to 75hz and then starts to get messy.

For small bookshelf speakers, this scheme will dramatically extend the life of your cones.  Tiny drivers just aren't made to do this kind of excursion.  Put your finger on the 10 inch woofer cone and ask yourself whether your bookshelf speakers should be trying to reproduce that.

NET-NET, WITH THESE TRIPATH AMPS, ASK ME TO CHANGE THE CAPS TO CUT OUT LOW FREQUENCIES FROM THE MAIN AMP.  PAY ONLY SHIPPING.

Seth





« Last Edit: 16 Jul 2014, 03:55 am by virtue »

megabigeye

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Re: Subwoofer hookup
« Reply #24 on: 15 Jul 2014, 01:42 pm »
Huh, I don't remember putting this in its own thread.  Good idea.  Thanks!

Thanks for experimenting with the sub high levels.  So you're not hearing any degradation in sound quality?  That was something I was a bit afraid of with my Dayton, but I remember being pleasantly surprised by what I heard.

I've left my setup using the One.3's sub out.  As I began to suspect, the horrible, huge mountain of frequency peak I was hearing at ~50Hz turned out to be more of a molehill.  Possibly not 100% perfect and ideal, but totally liveable. And I think it's just room acoustics, as it's actually worse where I sit on the couch.  More subdued in other parts of the room.

So I'm back to fully enjoying my One. 3!  Just thought I'd let you know.

virtue

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Re: Subwoofer hookup
« Reply #25 on: 15 Jul 2014, 02:21 pm »
Thanks for the update!

I don't hear a degradation in sound quality.

ericlp151

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Re: Subwoofer hookup
« Reply #26 on: 15 Jul 2014, 09:29 pm »
Personally I wouldn't run my speakers though an active sub.  If you want the purist sound, that just adds more connections and wire.

The crossover in a pair of bookshelf speakers sometimes has a choke set frequency for tweeters and sometimes a choke for midrange.   Depending on speaker specifications, whatever the woofer is rated at should be what the xover/choke is set for internally already in the speaker itself.  Usually the larger the speaker, the more bass is passed though.  Say, 55hz for a 6.5" woofer.  You can build your own choke. 

One can test this by going to youtube and search for subwoofer test tones.  Maybe the best way is to change out the output caps on the amp? 

It's obvious that 1 you don't want your woofer to produce the same frequency as your sub as they will cancel out each other and 2, you don't really want to play a midrange woofer at those levels since your pushing it to act as a sub and a mid range all at the same time and can distort or muddy the sound.  So the best way IMO, is to change the frequency coming from the amp itself. Tho, I'm not sure if that can be done (easily) on the one.3

Tho, if your just using a 3" driver (full range), you have no xover or chokes so you should be figuring out a way to protect that driver even more!  That is one reason why full range sounds better is because it doesn't have to run the sound through a xover/choke.

Best way to figure out where to place your subwoofer is place the subwoofer on the couch (listening area) and do the subwoofer crawl.  Basically crawl around the room to find out where it sounds best. 

Good Luck!

ericlp151

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Re: Subwoofer hookup
« Reply #27 on: 15 Jul 2014, 09:44 pm »
if there is a not an easy way to modify the amp.  One could get one of these.  Tho, it could affect the listening experience....

http://www.amazon.com/SX310-Pre-Amp-Electronic-Crossover-Subwoofer/dp/B001TE5YWU

Tho, you would have a lot of control on frequencies going into your speakers.  Might be just the ticket.

virtue

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Re: Subwoofer hookup
« Reply #28 on: 16 Jul 2014, 12:03 am »
A passive cross-over @ 100hz is vastly less damaging than something in the vocal range.

I would urge you to choose high quality equipment and listen carefully.

Cambridge is using a full-range mid-tweeters + woofer in its air line.  Most interesting.

virtue

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Re: Subwoofer hookup
« Reply #29 on: 16 Jul 2014, 03:50 am »
The fuse on my amp was blown this morning and the amp was dead.  I can only assume that this was a result of the subwoofer high-level input experiment, gone wrong.

JohnR

Re: Subwoofer hookup
« Reply #30 on: 16 Jul 2014, 06:25 am »
The fuse on my amp was blown this morning and the amp was dead.  I can only assume that this was a result of the subwoofer high-level input experiment, gone wrong.

Hi Seth, did you measure the impedance between the ground (black) connections on the sub?