Dead Zone in practice room last night.

stflbn · #1 05-20-2011, 08:43 AM

Oddly i've never had this happen before.

Set up my RS210 cab and F1 head, and started band practice.
Played a low E on my low B-string and poink... no big sound... dead, hollow, weak...

Fiddled around for a while with it, but finally just lived without for the 3 hours.

Debugged it in my head as either being a string gone bad, or a something trapping that specific frequency in the room. (Eb, E and F on that B-string were all weakish, but the E note was the deadest.)

Got home after wife was in bed and changed the strings out to a new set, and this morning tried everything through the rig before I came in to work and everything sounds fine.

So it was one or the other... string or room anomaly.

I've had strings go bad like that in certain spots before, but I've never personally ran into an area in a room that was that specifically dead.

What I was most worried about was that my Big Al 5 had acquired a deadspot on the 5th fret of the B-string... that would have been 'bad'

:: shrug ::

.

craig.p · #2 05-20-2011, 08:56 AM

Hm. I've never played in a room that didn't trap out certain frequencies, and it depended on where you were standing.

If this is the first time it's happened to you in this room, then the first thing to check would be for things in the room that were different this time. Even one cab (or a kick drum, or a big empty Anvil case, etc.) in a different spot than usual can cause what you experienced.

stflbn · #3 05-20-2011, 09:12 AM

Well... it was just 2 of us hammering through some different material last night, so I "stupidly" plopped my rig down IN A CORNER on a concrete floor... :: sigh ::

I know better... yet I paid no attention to my actions.

I've dealt with boom or muddiness, but never a tight 1 or 2 note killing freq. zone.

I'll move the amp around Monday night and see if I can recreate it.

Odd thing though, is that the note didn't die as an open E string. Only if played on the B-string. Which made me think it was more of a string issue than a frequency issue. Not sure if the two would vary enough for one to drop out and other not where an open string has more overtones.

.

craig.p · #4 05-20-2011, 10:46 AM

I think you're on to it with your comment about overtones. They're more likely to come through room anomalies relatively unscathed. I mean in terms of not going completely missing, lol.

It's also possible the fretted string died earlier than the open string because the instrument's effective mass is different than it is when you play an open.

Could be many things together creating a "perfect storm." Room anomaly plus cab placement plus fretted note plus bad string (winding came loose?). Just guessing. Tough to say for sure w/o being there.

**BLDavis** · #5 05-20-2011, 11:07 AM

A lot of "gremlins" can be defeated by moving your cab a foot or so in one direction or another. If, the stage has room enough to allow it. If your stuck in a corner like I was last nite there aint much you can do.
B.

Fuzzbass · #6 05-20-2011, 11:16 AM

Dead spots happen, all right. At a bar I play monthly, I just have to deal with the fact that the lowest A note will just die. It's only that one bar.

stflbn · #7 05-20-2011, 12:19 PM

Monday we're going to try to recreate it, then defuse it.

I also didn't have my Grammapad with me. Would have been interesting to see if that had any effect. I usually do toss it in with me and keep my 210 on it.

JimmyM · #8 05-20-2011, 01:52 PM

the gramma pad won't have any effect on that. you probably just had your cab far away enough from a wall to cause cancellation at that freq. i play this one place where i have to put my b-15 directly against the wal to keep it from cancelling out notes. it's a boundary effect that changes with the distance away from the wall.

stflbn · #9 05-20-2011, 02:51 PM

ya, figured. The RS210's are rear ported to boot, so not sure if that has any effect.

dbase · #10 05-20-2011, 05:24 PM

I have had that problem only at practice. The room is smaller than when we play gigs. I found out that the organ player was using his left hand for the bass parts out of habit for when when he's playing alone. It would dampen my notes played from my amp. Turning up the bass volume will usually win out of the keyboard.

JimmyM · #11 05-21-2011, 01:53 AM

Quote:

Originally Posted by stflbn

ya, figured. The RS210's are rear ported to boot, so not sure if that has any effect.

nah, port placement is irrelevant. boundary issues are a function of placement regardless of porting. as a matter of fact, there is some sort of frequency chart that tells you what freqs you'll lose at certain distances.