Out of Phase Bass

Tim G. · 3213

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Offline Tim G.

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on: August 05, 2011, 03:18:02 PM
I recently threw together some "bazooka" type speakers (based off the John Swenson design) using some FE206E Fostex speakers.

Setup:
Foreplay w/ Anticipation
Line Level BSC (currently setup with pots for tweaking)
Paramour's w/ Iron Upgrade
FE206E

Overall I have been pleasantly surprised at how good some cardboard tubes can sound, but the bass is always the elusive part.  I noticed that the bass seemed diffuse and thin (mids and vocals are very nice, and the fostex's don't beam like they have in other cabinets)  I wired one of the speakers out of phase just for a quick test and sure enough the bass was nice and full and the vocals were out of phase.

Any thoughts on what might be happening?  I could understand a little bit with a crossover in the mix but full range sans crossover I'm not sure where to go.   Any suggestions would be appreciated.

Thanks
Tim



Offline Grainger49

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Reply #1 on: August 05, 2011, 03:35:45 PM
All the music is coming through coherently except the bass?  That doesn't make sense.  If you get a good center image for the voices that indicates the system is in phase throughout.  The bass should be in phase too. 

Could it be the BSC messing with the low frequencies?



Offline Tim G.

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Reply #2 on: August 05, 2011, 03:45:15 PM
Absolutely, that is what seemed really weird to me.. and certainly that would make the most sense, and I can't say I took the simple step of removing the bsc to compare. (I wonder if I screwed up the wiring on the bsc and somehow got something swapped around)  I will do that and see what it sounds like. 

And yes the soundstage with these is actually quite good, I have always thought the fostex speakers beamed too much and always preferred my Straight 8's but in this configuration they really setup a sound stage as nice as the S8's.




Offline Grainger49

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Reply #3 on: August 06, 2011, 04:04:36 AM
I have Herbie Mann (Live) At The Village Gate.  I have had this album a long time and the flue always sounded odd.  

Sometime in the 70s I bought a Technics four channel scope.  On this scope normal stereo sound appeared straight up and down with some side to side spread.  Playing the Herbie Mann album I saw that the flute appeared as a horizontal line.  The flute was recorded in stereo but 180 degrees out of phase with the music.  I swapped the speaker lead on one speaker then the flute was solidly in the center and everything else sounded odd.  

This to say some recordings are not carefully phased, even studio albums.  

So does the bass seem out of phase on all recordings?
« Last Edit: August 07, 2011, 01:42:48 PM by Grainger49 »



Offline Tim G.

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Reply #4 on: August 07, 2011, 10:11:52 AM
Well..it wasn't the bsc circuit, I removed it and there wasn't much of a difference.  But I did end up setting these in my normal listening position and that resolved the issue completely.  It must have been some weird room interaction, I noticed when I was tinkering with the bsc that if you stood right between them the bass sounded like it should.   Where they are now they are pointing 90 degrees around from where they were pointed in the first place.  Found some sort of bass sucking sweet spot!

I had no no idea they could get something that out of whack in a recording, but I remember that is how I first learned hoe to use a scope.  I had one hooked up to a stereo I had in my room and had it on almost all the time I listened to music...just because it looked cool...

Thanks for the suggestions
Tim