Combining sealed (EP800) and ported (EP600) subs ?
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Hi all -
In a post on Audioholics, it was suggested to me that running a sealed and ported sub together might result in sub-par performance due to "group delay." This was a new term to me, so I've researched it enough to understand what it means (slower delivery of certain frequencies in ported subs versus sealed), but don't know how much of a problem to expect it to be if I try to run both of these subs together.
While I'm not sure that I'll ultimately keep both of these subs anyway, I'd appreciate any advice on the matter.
Thanks.
Jason
Epic 80-800: HG Cherry
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Jun 2003
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axiomite
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axiomite
Joined: Jun 2003
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Oh, you do NOT want group delay.
Just send me the EP600.
bibere usque ad hilaritatem
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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shareholder in the making
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shareholder in the making
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To expand on Tom's idea, keep the 600 and send me the 800
Jason M80 v2 VP160 v3 QS8 v2 PB13 Ultra Denon 3808 Samsung 85" Q70
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Oct 2006
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axiomite
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axiomite
Joined: Oct 2006
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No no, they don't match. Send me both!
With great power comes Awesome irresponsibility.
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Jun 2003
Posts: 8,488
axiomite
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axiomite
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We're Helping!
bibere usque ad hilaritatem
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Feb 2008
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connoisseur
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OP
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Great, thanks all. Glad to hear I didn't have a real problem that couldn't easily be solved.
Epic 80-800: HG Cherry
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Dec 2003
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shareholder in the making
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shareholder in the making
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Jason M80 v2 VP160 v3 QS8 v2 PB13 Ultra Denon 3808 Samsung 85" Q70
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Jul 2006
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Founder, Axiom Upgrade Club shareholder in the making
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Founder, Axiom Upgrade Club shareholder in the making
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There was certainly no delay in this group's assistance.
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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shareholder in the making
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shareholder in the making
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We stand ready to help you as well, Charles. Just say the word.
I am the Doctor, and THIS... is my SPOON!
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Founder, Axiom Upgrade Club shareholder in the making
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Founder, Axiom Upgrade Club shareholder in the making
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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shareholder in the making
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shareholder in the making
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So if I get you to say no, I can have your EP600?
I am the Doctor, and THIS... is my SPOON!
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Jul 2006
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Founder, Axiom Upgrade Club shareholder in the making
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Founder, Axiom Upgrade Club shareholder in the making
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It may already be spoken for, unfortunately. It's up in the air.
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Dec 2003
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shareholder in the making
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shareholder in the making
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The magic around here is getting very strong, now we have an EP600 up in the air to go along with the floating Audyssey mic. I wonder if the moons are aligning or something.
Jason M80 v2 VP160 v3 QS8 v2 PB13 Ultra Denon 3808 Samsung 85" Q70
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Jul 2006
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Founder, Axiom Upgrade Club shareholder in the making
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Founder, Axiom Upgrade Club shareholder in the making
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I wonder if the moons are aligning or something. That made me think of Braveheart.
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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shareholder in the making
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shareholder in the making
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Braveheart.... the Care Bear?
Jason M80 v2 VP160 v3 QS8 v2 PB13 Ultra Denon 3808 Samsung 85" Q70
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Apr 2003
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shareholder in the making
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shareholder in the making
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Every man dies, not every man really lives with a kick-ass sub?
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Apr 2007
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connoisseur
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connoisseur
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so where is JohnK with a meaningful post when you need him?
-David
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Jun 2003
Posts: 8,488
axiomite
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axiomite
Joined: Jun 2003
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Seriously. Has there EVER been less actual discussion of a sincere and relevant question?
bibere usque ad hilaritatem
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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connoisseur
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OP
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I didn't want to be the one to say it, but since Tom/David started it, and now that we're on PAGE 2 of responses with no relevant information, any attempts at a serious answer? (by the way, if this is your way of exhibiting "meaningful response group delay," congratulations, you've done it!) Jason
Epic 80-800: HG Cherry
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Mar 2005
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axiomite
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axiomite
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Hi all -
In a post on Audioholics, it was suggested to me that running a sealed and ported sub together might result in sub-par performance due to "group delay." This was a new term to me, so I've researched it enough to understand what it means (slower delivery of certain frequencies in ported subs versus sealed), but don't know how much of a problem to expect it to be if I try to run both of these subs together.
While I'm not sure that I'll ultimately keep both of these subs anyway, I'd appreciate any advice on the matter.
Thanks.
Jason
Jason, I run a ported sub (Hsu VTF3 MkII) with two smaller 10" sealed subs. I'm not familiar with group delay, though. I'll check out that article when I get home. So far, I haven't noticed anything wrong with the set-up. If anything, I get a more even distribution of bass at my listening position. I just recently turned Audyssey off on my receiver and the bass seems a bit better on movies. By the way, I don't use the subs for music, only HT and games. Ideally, I want to get more ported subs to go with the Hsu. Why? Just to add a bit more thump and rumble to my movies. Oh, and Tom, you started it. . .
*********** "Nothin' up my sleeve. . ." --Bullwinkle J. Moose
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Dec 2003
Posts: 10,420
shareholder in the making
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shareholder in the making
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I did try the EP400 with my old ported sub and I had no discernable issues, but your situation involves so much better subs than those. I will guess that a phase adjustment could offset any delays that you might find.
Jason M80 v2 VP160 v3 QS8 v2 PB13 Ultra Denon 3808 Samsung 85" Q70
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Jun 2003
Posts: 8,488
axiomite
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axiomite
Joined: Jun 2003
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Started what?
Okay, here's my assessment...
1. Jason's room is too small - and the subject wavelengths too long - for him to possibly have meaningful response group delay that he can discern.
2. Jason loves to buy new A/V toys and tweak the bejeezus out of them. He's not going to stop.
3. We like Jason. And his stuff.
4. Nobody here knows diddly-squat about his problem or cares enough to learn.
5. Puppies are overrated.
6. Mark's room still sucks.
bibere usque ad hilaritatem
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Sep 2004
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shareholder in the making
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shareholder in the making
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Puppies are NOT overrated.
Good day sir!
I say: Good DAY!
Harrummmph...
::::::: No disrespect to Axiom, but my favorite woofer is my yellow lab :::::::
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Mar 2005
Posts: 7,463 Likes: 1
axiomite
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axiomite
Joined: Mar 2005
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Ha ha. We really try hard to answer questions from newcomers. If a forum vet asks something, though, we go into thread-jacking overdrive.
*********** "Nothin' up my sleeve. . ." --Bullwinkle J. Moose
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Feb 2008
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connoisseur
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OP
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I see that. I'll try going out on a limb and asking Alan to have a look at this thread (the first post at least). But don't let them stop anyone else from trying to answer in the meantime. Jason
Epic 80-800: HG Cherry
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Jun 2003
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axiomite
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axiomite
Joined: Jun 2003
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Answer what? Why Mark is channeling Dustin Hoffman in drag?
Oh, the thread topic. Right. Sorry.
bibere usque ad hilaritatem
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Dec 2007
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axiomite
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axiomite
Joined: Dec 2007
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Fred
------- Blujays1: Spending Fred's money one bottle at a time, no two... Oh crap!
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Dec 2003
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shareholder in the making
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shareholder in the making
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Jason M80 v2 VP160 v3 QS8 v2 PB13 Ultra Denon 3808 Samsung 85" Q70
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Apr 2007
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connoisseur
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connoisseur
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-David
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Apr 2003
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shareholder in the making
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shareholder in the making
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Something that comes easily unraveled with the slightest tug.
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Jul 2004
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connoisseur
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connoisseur
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To the OP…….
Considering the incredibly insightful responses you’ve received specifically addressing your question, you can assume with confidence that this crowd either does not know the answer, or they think the differences will be so insignificant that discussing them isn’t worth the effort.
Go ahead and use both subs if you wish. The differences in delay will be so slight, only a very small percentage of humans will be able to hear a difference.
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Jun 2003
Posts: 8,488
axiomite
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axiomite
Joined: Jun 2003
Posts: 8,488 |
Isn't that what I said already? I was irrelevant BEFORE Mike was irrelevant! Nice post 2300, though, my friend Is it cocktail hour yet?
bibere usque ad hilaritatem
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Feb 2006
Posts: 6,471
axiomite
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axiomite
Joined: Feb 2006
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I would like to point out that I was not part of the hijacking on at least one thread on the Axiom message boards.
That is all.
Bears, beets, Battlestar Galactica.
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Feb 2008
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connoisseur
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OP
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I'd like you all to know that Alan responded to my PM directly, and since none of you were any help and went out of your way to hijack my thread, I think I'll keep the information to myself for awhile! Take that!
Epic 80-800: HG Cherry
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Jun 2003
Posts: 8,488
axiomite
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axiomite
Joined: Jun 2003
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bibere usque ad hilaritatem
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Dec 2003
Posts: 10,420
shareholder in the making
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shareholder in the making
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Hey I did add my .02 worth of actual knowledge on the subject, ok maybe it was more like.005, but I did try.
Jason M80 v2 VP160 v3 QS8 v2 PB13 Ultra Denon 3808 Samsung 85" Q70
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Apr 2003
Posts: 16,441
shareholder in the making
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shareholder in the making
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The problem with your $.02 is that nobody carries pennies anymore so they couldn't give you change.
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Feb 2008
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connoisseur
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OP
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Hey Jay, good point... Here's what I owe you & mdrew (no one else is allowed to look).
Epic 80-800: HG Cherry
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Dec 2003
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shareholder in the making
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shareholder in the making
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Considering the first words are addressed to 'Jason' I think I quailfy to see the whole thing
Jason M80 v2 VP160 v3 QS8 v2 PB13 Ultra Denon 3808 Samsung 85" Q70
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Jul 2004
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connoisseur
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connoisseur
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I have to admit that this thread is one of most humerous I've read in a long time.....
2300 posts in four years.....crap, I need a life.
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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shareholder in the making
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Hi Jason and all,
Here are some informed comments on group delay at low bass frequencies. I posed the question to Tom Cumberland, Axiom's chief R & D engineer, who answered me this way:
"The issue of group delay can best be explained by moving a sub one to two feet in a given direction. This being said, there is group delay in everything that relates to room placement. Whether a sub is ported or sealed only affects its overall frequency response. Of course, a smooth linear response is the optimal performance from any loudspeaker. Simply moving a subwoofer around the room creates group delay. This movement, of course, helps remove the nulls and peaks in the frequency response in the room whether it is one sub or multiple subs."
I think this is helpful. There may be updates to this as I learn more.
Regards Alan
Alan Lofft, Axiom Resident Expert (Retired)
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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connoisseur
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OP
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Aww Alan, you broke the silence, and I really had these guys going! Seriously, thank you for reviewing my question and passing it along to Tom & others. It's nice to know it's not anything to be seriously concerned about, but if you hear from some of the other folks you mentioned you'd be asking, I'll look forward to hearing more. Even though it sounds like it's not going to cause a problem in my room, it's something I hadn't ever heard of before this, so it's interesting to learn more about it. Thanks again. Jason
Last edited by myrison; 10/31/08 10:33 PM.
Epic 80-800: HG Cherry
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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connoisseur
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OP
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For anyone interested, I found this report on group delay. It's fairly complicated and admittedly lost me at certain points, but what I read in the report seems to confirm that the difference between a good vented sub and a good sealed sub aren't likely to be large cause for concern. In this test, the difference of max delay between their vented and sealed sub was around 2 hundredths of a second. If anyone is up for more Q&A (a dangerous proposition I've seen), I'd be interested in a brief explanation of what the author means when he says that one system is a "second order system" and another is "a fifth order system." I've heard those terms before but do not understand the distinction. Jason
Epic 80-800: HG Cherry
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Jason, as Mike Drew suggested above, when I saw the question I frankly wasn't interested to either just comment that the difference was almost certainly insignificant or to research for an authority to lend some weight to that view. Since you've taken the time to find that good Audire explanation(which I hadn't seen before), I decided to try to retrieve some of the stuff that I'd seen in the past. One thing that stuck in my mind was this discussion by physicist and speaker designer John Murphy taken from some of his posts on an audio discussion group. Scrolling down to the June 2, 1999 post, his concept of relating the amount of group delay that might be audible to how many "cycles" it equated to at very low subwoofer frequencies seems quite powerful and the one cycle threshold for audibility that he proposed seems reasonable. As shown in his example there involving the ACI driver, the amount of group delay for even the vented system was well under one cycle. The difference between the vented and closed enclosures was still smaller of course, and even less likely to be audible. So, my view(not that I've spent much time pondering the question)has been that this isn't of real-world significance. As to the "orders" of the various enclosure types, the significance lies in how rapidly the response rolls off below the tuned frequency, which is quite important(and how the group delay at the lower frequencies increases in proportion to the steepness of the rolloff, apparently not very important). The rolloff is 6dB per octave per "order", e.g., a closed enclosure said to be 2nd order rolls off at 12dB per octave, a vented 4th order enclosure rolls off at 24db per octave.The way the numbering of the orders arises is through the analogy to electrical(rather than acoustical)crossovers which also create rolloffs. A first order crossover contains basically just one element(a capacitor in series with the tweeter, an inductor with the woofer)per driver and rolls it off at 6db/octave above(woofer)or below(tweeter)the selected crossover frequency. As more elements are added to the crossover to increase the steepness of the rolloff, the number of elements determines the order of the crossover; e.g., in a second order crossover both an inductor and capacitor are used for each driver, series capacitor and parallel inductor to the tweeter, series inductor and parallel capacitor to the woofer, resulting in a 12dB/octave rolloff. As more elements are added there can be 3rd order, 4th order, etc. crossovers with proportionally steeper rolloffs but also higher power losses in the crossover.
-----------------------------------
Enjoy the music, not the equipment.
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Founder, Axiom Upgrade Club shareholder in the making
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Founder, Axiom Upgrade Club shareholder in the making
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I love when I have just the vaguest idea what someone might be talking about.
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Dec 2003
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shareholder in the making
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shareholder in the making
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Glad to see I am not the only one .
Jason M80 v2 VP160 v3 QS8 v2 PB13 Ultra Denon 3808 Samsung 85" Q70
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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aficionado
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aficionado
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Dems lots o purdy wurds!
Epic 80 / SVS PB13 Ultra Denon 3805 / M2200 Outlaw Monos / Sammy 55" LED
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Feb 2008
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connoisseur
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OP
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John - thank you for the informative response. It only took us 4 pages as a group to get to this point , but it was worthwhile as I'm now learning something new. Thank you for taking the time to research and respond. Jason
Epic 80-800: HG Cherry
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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Joined: Dec 2003
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shareholder in the making
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shareholder in the making
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Only 4 pages!?, We must be slipping...
Jason M80 v2 VP160 v3 QS8 v2 PB13 Ultra Denon 3808 Samsung 85" Q70
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Re: Combining sealed (EP800) and ported (EP600) subs ?
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OP
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I don't even have the 800 yet. Give it time.
Epic 80-800: HG Cherry
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