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Embarassing admission: speakers out of phase . . .

BrianZ

Active Member
. . . for the last 9 years. :oops:

i bought my Paradigm Studio 20 v3's in 2005 (learned about them in the S&V forum) and fairly quickly discovered one of the woofer drivers was bad. no sweat, the retailer sent me a new one, i installed it, problem solved. somehow i was convinced that i got the positive & negative right (don't remember now) and never gave it another thought. but over the years i had always i felt they sounded a little odd when you were front & center of them, but i perceived it as just kinda extra spacious. since so many reviewers talked about their excellent sound stage i just chalked it up to that. granted it was so wide as to be a kinda distracting, but i loved the frequency balance and the natural sound so much that i just kind looked passed it. "i guess i just don't like a wide sound stage as much as everyone else - no biggie." i preferred the sound when sitting just a little off center because when dead center the vocals tended to get kinda lost. in fact it always kinda bothered me that vocals really sounded best when i was in an adjacent room! and sitting right in the the middle also kinda made my ears kinda feel weird, like a tickle or tingle. i mean, i really should have known something was wrong. jesus, what an idiot. so i've spent the last 9 years occasionally tweaking their positioning in an effort to reduce the soundstage, lol. and don't even get me started on all the trouble i've had trying to dial in the sub i got last year.

anyway a couple months ago i took the 20's up to my bedroom to do some testing & auditioning while building a small & inexpensive bedroom system (settled on a set of PSB Alpha B1's). that 'spaciousness' in the 20's now sounded simply too weird to be ignored when directly compared to the Alphas, and that's when it occurred to me that it's possible i wired that replacement woofer wrong so many years ago. so today i finally got around to pulling out the woofers to compare and confirmed my suspicion. voila - my vocals are back up front & center where they should be. this is really embarrassing, not to mention how annoyed i am to have missed out on great sound for all these years. on the upside, it's like getting a great new set of speakers for free! but now i gotta start over in dialing in my sub.

did i mention what a f~cking idiot i am?
 
:laughing: Sorry man. It's totally understandable. It's so easy in this hobby to hear what we THINK we should be hearing, or what other tell us we should be hearing. I ran my main HT for several days with a blown tweeter in one of the mains before it occurred to me to wonder why some stuff seemed to sound a bit off-center.

Well as long as you still enjoyed your music for music's sake, it's no loss.
 
9 years is an extended time, which begs the question. Have you bothered to use an audio setup disc with polarity/phase section?

Rope
 
Rope said:
9 years is an extended time, which begs the question. Have you bothered to use an audio setup disc with polarity/phase section?

Rope

Uh, no. Was not even aware of such a thing. Willl it help me dial in my sub? Cuz I'd like to finally do that right and don't feel like shelling out for a nice neutral mic to use with the free audio testing software I have on the laptop.
 
The best audio portion (video section is useless) setup disc I have experienced is AVIA Guide to Home Theater. Perhaps others exist which are better, but that information will have to be supplied by others.

As Zing alludes to, a analog SPL meter is a must have for setting up an audio system.

Rope
 
Years and years and years ago I set out to build an unpowered subwoofer. It was at least partially inspired by an article I had read in Audio. ("Subwoofers" were really not known back then.)

I did my research, saved up my pennies, and then purchased two huge expensive 18" woofers. I drafted up the plans for the cabinet - to be crafted and internally braced with extra high density particle board. It was to be huge. Bigger than a big chest freezer.

Since I did not have the tools to properly fix and cut the pieces I had a local master carpenter do it for me.

I did the final assembly in my apartment - lots of screws and glue.

I mated the final sub to a huge power amp, hooked the whole thing up to my system (with a dbx100 in the loop), fired it up, and...

Lunch bag letdown. It was weak. Anemic. Pathetic. I had spent $$$$ and hrs&hrs and it barely made a peep. Dual woofers were moving like crazy, but no extra bass worth speaking of.

So I stripped out the woofers and luckily I was able to send them back for a full refund - just the shipping costs both ways out of pocket. The assembled cabinet was too big to get out of my apartment door. (Not sure what I was thinking there!) So I basically had to use a sledgehammer to disassemble it.

As I was finishing I happened to notice something about the speaker leads/posts. I had built in two sets of posts - one for each woofer, to be each driven by a single amp channel. But guess what?

Yup. Internally I had wired one of them in reverse. So the two woofers were firing 180 degrees out of phase.

Never told anyone this tale before.

I'm still embarrassed!

Jeff

ps. A few years later I tried my hand at a passive sub again - using four brand new 6.5" polk "woofers" and a 12" polk passive radiator that I had acquired in trade for a six pack of beer. Extra high density particle board again - but a much smaller cabinet. This time I was ultra careful with the wiring. It worked like a charm. I used it for well over a decade.
 
holy crap, Jeff! that totally sucks. thanks for sharing that. :)

and thanks Rope for the info on the Avia disc. off to Amazon . . .

and any recommendations on a cheap SPL meter?

like i said, i have this software on my laptop that displays curves as well as generating test signals (can't remember the name right now). but what i don't have is a linear testing mic so i haven't been able to use the software effectively, and so instead have been calibrating my sub by ear. not sure how the Avia disc and SPL meter work to accomplish this but i'll take everyone's word on it. i'm sure it will make sense once i get it all.
 
I might be mistaken, Rat Shack discontinued their analog SPL meter and offer a digital meter, which suck!

Without breaking the bank, I'd be inclined to d/l an analog app (.99-$3.00) and see what results are gained. However, the mic in your device comes into play in terms of accuracy.
:text-link:

Rope
 
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